Helium resource in Weihe Basin is abundant and holds great potential for exploration and development. Based on the research process related to helium resource in Weihe Basin，the exploration history，helium source rock，helium carrier and groundwater system，theoretical models of helium accumulation，resource quantity forecast，and prospect priority were summarized，and the existing issues and countermeasures for key techniques in helium exploration and development were discussed. Research findings show that：（1）Helium resource in Weihe Basin was discovered in 1970s，including methods of gravity，magnetics，geochemistry，seismics，and drilling，as well as the latest deployed five helium exclusive exploration wells. However，the exploration level remains low.（2）Helium source rocks widely distributed in the basement and south margin of Weihe Basin show significant potential for helium generation. The effectiveness is closely related to key factors，such as the content of radioactive elements of Th and U，formation age and characteristics of geological structure. The Late Paleozoic coal-bearing strata may remain in the deep basin，providing a carrier gas source for the upward migration of deep helium. Helium-rich natural gas is closely associated with groundwater，and the carrier gas and formation pore-pore water are important carriers for helium migration and enrichment. Based on the genetic method，the effective helium resources in Weihe Basin are estimated to be 33.8×10⁸ m³. Considering the overlapping characteristics of geothermal energy，biogenic gas and helium resource in Weihe Basin，Huazhou-Tongguan area is identified as an important target area for comprehensive exploration and development of multiple resources.（3）The helium exploration well drilled into Archean metamorphic rock basement and IndosinianYanshannian granite. Formation conditions of helium-rich natural gas in Huazhou exploration area are controlled by various factors，such as helium source rock，deep faults，and effective sealing conditions.（4）The exploration and development of helium resource in Weihe Basin still faces several problems and challenges，such as inability to accurately assess helium reserve，significant difficulties in exploration，need for improvement in key engineering technologies，and the requirement for further study of economic sustainability. In response，the related countermeasures have been proposed，including strengthening seismic data processing and technology research of helium downhole engineering，optimizing the matching technique of safe drilling，and trying to carry out the related work about extraction and concentration of helium at wellhead.

Based on analogies from modern sedimentary satellite imagery，integrated with core，well-logging， and production dynamic data，the microfacies types and distribution characteristics of anastomosing rivers from Member 4 of Miocene Guantao Formation in Lindong area of Dongying Sag were analyzed. The reservoir sandbody was characterized，and a multivariate classification model was established. The results show that： （1）The anastomosing rivers in Lindong area can be divided into four microfacies： channel，natural levee，crevasse splay，and interchannel. In plan view， channel sandbodies exhibit an anastomosing network with low-sinuosity single channel segments， while confluences form moderate-to-high-sinuosity interconnected channels. In crosssection，sandbodies exhibit flat-topped and convex-based lenticular geometries，locally superimpose to form “sand walls”，exceeding 10 m in thickness. Natural levee sandbodies distribute on both sides of the river channels， with width of 18-430 m；in cross-section，display as wedge-shaped， with thickness less than 3 m. Crevasse splays develop sparsely，showing fan-shaped geometry in plan view，and in cross-section they form wedgeshaped thin layers， with thickness of 3-5 m. Interchannels extensively develop，accounting for 43%-70% of the study area.（2）Guantao Formation anastomosing rivers share similarities with the modern Nenjiang anastomosing river in terms of sedimentary environment，microfacies，hydrodynamics，and geomorphic evolution. Its channel sandbodies exhibit NW-SE direction of long-axis and display contiguous distribution with favorable continuity in plan view.（3）Single channels in the study area are small-scale，with width of 65-170 m and thickness less than 5 m，developing two types of architectural splicing patterns： channel-channel connectivity and channel-natural levee contact.（4）Production performance post-waterflooding and tracer dynamic analyses show that singlechannel sandbodies are developed in injection-production well along the NW-SE provenance direction，preferential waterflooding/tracer migration paths aligned with paleochannel orientation. Interchannel mudstones and lowpermeability natural levees act as flow barriers.

Based on the theory of continuous accumulation and the data of seismic，drilling ，master logging， well logging and core testing，the hydrocarbon accumulation conditions of Jiufotang Formation in Ludong Sag of Kailu Basin were studied from multiple aspects，including the tectonic sedimentary evolution background and its controlled source rocks，reservoirs，and reservoir characteristics of the Jiufotang Formation. The continuous accumulation patterns and favorable exploration targets in this area were clarified. The results show that：（1）Ludong Sag presents a single-fault half-graben configuration，where the steep slope zone serves as the main source supply area of the original sedimentary source，while the gentle slope zone is the main uplift and denudation area in the late stage，the main part of the original sedimentary subsidence center exists in current structure. The sedimentation of Jiufotang Formation is controlled by the staged activities of the sag-controlling fault. In the sedimentary stage with low sedimentation rate and relatively shallow water conditions，large fan deltas are developed in the steep slope zone，and the sand bodies are in the state of“pervasive sand distribution”.（2）Two source rock intervals are identified in Jiufotang Formation in the research area：tuffaceous mudstones in lower member of Jiufotang Formation and oil shales（Oil Groups Ⅰ-Ⅲ）in upper member of Jiufotang Formation，both of them are good source rocks with low maturity to maturity. The principal source rocks are the oil shales（Oil Groups Ⅰ- Ⅲ），with the chloroform bitumen‘A’of 0.48%，TOC of 4.47%，total hydrocarbon of 2 377 mg/L，organic matter type mainly consisting of type Ⅰ and Ⅱ₁，and vitrinite reflectance of 0.64%. A small amount of conventional sandstone reservoirs are developed in the underwater distributary channel of the fan delta front. The tight sandstone reservoirs are widely and continuously distributed，and the lacustrine carbonate reservoirs are developed in the center of the subsag. Influenced by the effects of provenance supply and water environment，the storage space of different types of reservoirs develop sequentially. Intergranular（dissolved）pores in coarse sandstones， intragranular dissolved pores in fine sandstones，matrix dissolution pores in dolomitic mudstones，and carbonate dissolution pores are widely developed. Thick dark mudstone developed in Shahai Formation can be used as regional cap rock（. 3）The source-reservoir in the subsag area is integrated，and with superior preservation conditions. Different types of reservoirs are continuously developed. Conventional oil-tight oil-shale reservoirs are successively developed on the plane，and multiple types are superimposed vertically. Houhe and Jiaolige fan bodies have shown promising exploration results，while Kuluntala and Qinghe fan bodies are favorable areas for exploration.

Based on analysis and experiment data of fluid inclusions, hydrocarbon generation thermal simulation, TOC, physical properties and casting thin sections, combined with burial-thermal history, the geological condition, accumulation process, and main controlling factors of Miocene Sanya Formation in Yingdong slope area of Yinggehai Basin were systematically studied, and hydrocarbon accumulation models were established. The results show that: (1) The organic matter type of Miocene Sanya Formation source rocks in Yingdong slope area of Yinggehai Basin is dominated by humic kerogen, with average TOC values of 0.77% and 1.21% in the northern and southern sections, respectively. The average TOC value of Oligocene coal-bearing source rocks is 1.41%. The evolution characteristics of Oligocene and Miocene source rocks in Yingdong slope area are as follows: early shallow burial, long-term immaturity-low maturity stage, late rapid deep burial, short-term rapid entry into maturity-high maturity evolution stage. The evolution degree of source rocks in the near-sag area of the southern section is the highest, followed by the slope area of the southern section, the near-sag area of the middle section and the northern section, and the evolution degree of the slope area of the middle section is the lowest. The average porosity of reservoir in the northern section is 13.56%, and the main peak of permeability is 0.1-1.0 mD. The average porosity of the southern section is 11.53%, and the main peak of permeability is 1.0-10.0 mD, the permeability is significantly better than that of the northern section, and the reservoir space is mainly composed of dissolved pores. The composite transport system composed of continuous active strike-slip faults, derived fractures and large-scale sandbodies with relatively good physical properties ensured the efficient three-dimensional migration of natural gas.(2) The natural gas component of Sanya Formation is mainly CH₄, with a median volume fraction of 83.16%, mainly coal-type gas. Natural gas of the northern section mainly comes from Sanya Formation and the underlying Oligocene, while the maturity of natural gas in the southern section is 1.3%-1.7%, significantly higher than that of the northern section, mainly from the underlying Oligocene.(3) Characteristics of Sanya Formation gas reservoir are"multi-stage continuous filling and late-stage accumulation". Both the northern and southern sections have undergone three-stage of oil and gas charging, with the main charging period being Pleistocene. The main charging time of oil and gas in the southern section(3.5-1.0 Ma)is earlier than that in the northern section(2.2-1.0 Ma). The filling abundance of the southern section is higher than that of the northern section.(4) Accumulation characteristics of Sanya Formation are"strike-slip fault controlling hydrocarbon, source superimposed tectonic activity controlling reservoir, superposition of strike-slip fault activity-fracture overpressure activation controlling transportation". The source rock evolution, transport efficient and reservoir features are the main controlling factors for natural gas accumulation.

Yin’e Basin exhibits relative low degree of hydrocarbon exploration，and the distribution law and exploration direction of oil and gas require further clarification. By analyzing the oil and gas exploration history of Yin’e Basin，the exploration progress and existing problems in different stages were sorted out，the drilling understanding was summarized，and the reservoir types and exploration direction were clarified. The results show that：（1）Yin’e Basin has experienced four exploration stages：reconnaissance，comprehensive evaluation，key depression exploration and overall understanding. Taking Cretaceous-Jurassic and Carboniferous-Permian as the target layers，as the research of oil and gas accumulation conditions in the basin gradually deepen，and great progress has been made.（2）During the stage of reconnaissance，gravity-magnetic，electrical，and seismic were applied to delineate the distribution range of key sags and deployed two-dimensional seismic. In the stage of comprehensive evaluation，taking Mesozoic as the target layer，the tectonic units of the basin were divided，and the low-yield oil flow was discovered in Chagan and Lujing sags according to the high-point hydrocarbon-controlling model of fault structure. In the stage of key depression exploration，taking Mesozoic and Upper Paleozoic as the target layers，and the industrial oil and gas flows were achieved in Hari Sag，Guaizihu Sag and Tiancao Sag. However，debates persist on whether oil-producing series belong to Mesozoic or Late Paleozoic. In the stage of overall understanding the basin and the re-division of tectonic units，the current structure of the basin were clarified. It was pointed out that Carboniferous-Permian was the fold basement of the Mesozoic faulted basin，and hydrocarbon accumulation models of Mesozoic lithologic reservoir and pre-Mesozoic buried hill were established. The oil and gas are mainly distributed in small-scale area of the lower part of each Mesozoic dustpan-shaped faulted gentle slope，and the resources are relatively scattered.（3）Yin’e Basin is a Mesozoic faulted basin developed on the folded basement of the Hercynian orogenic belt. The main oil and gas producing strata and oil and gas sources are Mesozoic，and Upper Paleozoic has experienced different degree of deformation and metamorphism，with limited hydrocarbon potential. The unconventional oil and gas reservoirs，such as thick lacustrine mudstone and argillaceous shale in Mesozoic Cretaceous and Jurassic are the key targets for next-phase exploration of the basin.

The exploration of Jurassic coal-rock gas in Qaidam Basin is in its early stage and has great exploration potential. Based on outcrop，drilling，seismic，and experimental analysis data，the distribution and quality characteristics of Jurassic coal rock were analyzed. The reservoir formation conditions were evaluated from four aspects： gas generation capacity，reservoir conditions，reservoir-cap assemblages，and gas-bearing properties. And reservoir formation models and resource potential were clarified. The results show that： （1）Jurassic coal rocks in Qaidam Basin are mainly distributed in Middle-Lower Jurassic Hushan Formation，Xiaomeigou Formation，and Dameigou Formation，with large thickness，wide distribution area，distributed from the surface in front of the mountain to the hinterland of the basin（buried at a depth of nearly 10 000 meters），strong gas generation capacity，providing good material foundation for the generation of coal rock gas. The coal rocks are mainly semi-bright coal and bright coal，with high vitrinite content（average volume fraction of 65.5%）. Characterized by high volatile matter and ultra-low moisture content ，the coal rocks have good quality（. 2）The lithologies of Jurassic coal seams in the research area are mainly mudstone，carbonaceous mudstone，and coal rock， with coal rock thickness of 1.0-80.0 m，an average TOC value of 57.60%，an average hydrocarbon generation potential（S₁+S₂） of 79.9 mg/g，hydrogen index reaching up to 165 mg/g，and burial depth of over 4 500 m in the basin hinterland. R_o is generally greater than 1.5%，and can reach up to 3.5%，indicating strong overall gas generation capacity.There are four types of pores，such as pores，microcracks，residual tissue pores，and mineral intergranular pores. High proportions of meso-macropores provide reservior conditions rich in free gas. Two types（coal slurry and coal sand）of reservoir-cap assemblages are formed in the lacustrine sedimentary environment（3）Jurassic coal seams in the research area develop two types of reservoir formation models： self-generation and self-storage， and lower-generation and upper-storage. The preliminary estimate of coal-rock gas resources is 2.32×10¹² m³， with great exploration potential. Middle Jurassic in Yuka-Jiulongshan area and Lower Jurassic in Niudong-Lenghu area represent the most favorable exploration targets for deep coal-rock gas in Qaidam Basin.

Based on the fine structural interpretation of seismic data，Triassic synsedimentary faults in Kuqa Depression of Tarim Basin were studied by using the impression method，and the pre-sedimentary paleomorphology of Triassic was restored，and their controlling effects on sedimentation were clarified. The results show that： （1）Triassic of Kuqa Depression develops four rows of synsedimentary reverse faults，including Kubei fault， Bashi-Yiqicreek fault，Kela-Yangbei fault and Keshen fault，which are structurally stacked，and the front zone reaches the south of Kelasu tectonic belt. （2） Triassic paleogeomorphology is distributed in an east-west direction，with the South Tianshan orogenic belt in the north and the foreland basin uplift in the south. The central part is the structural low part of Kuqa Depression，which is constrained by the local low bulge，and develops Wushi Sag，Baicheng Sag and Yangxia Sag. The northern boundary of the prototype basin is located 24-51 km north of the current basin boundary，and the area of the prototype basin is 11 913 km² larger than that of the present basin.（3）The sedimentation and evolution of Triassic in the study area are controlled by the paleotectonic pattern，which is generally manifested as a wedge-shape that gradually thickening from south to north，with a tendency of thickening from west to east，and the distribution of strata in the north-south direction is asymmetrical. Due to the weakening orogeny of South Tianshan，Triassic has a complete foreland basin extrusion-relaxation pattern.Okhobrak Formation develops fan delta，the lower part of Karamay Formation and Huangshanjie Formation are semi-deep lake and deep lake sediments.The upper part of Huangshanjie Formation and Tarichik Formation are the transformation of the flood plain from the semi-deep lake and deep lake to the meandering river，which vertically constitutes a complete sedimentary cycle of continental lake basin evolution. The ascending walls of the syngenetic reverse faults all have the function of secondary provenance，and form a good spatial combination of reservoirs and caps in the lower wall，which is a favorable potential exploration field.

Through the incorporation of bedrock governing equations，fracture governing equations，and thermal-hydraulic-mechanical（THM）coupling relationships，and aidded by COMSOL software，numerical simulation research on the development of CO₂-EGS hot dry rock reservoirs via horizontal wells under multicluster fracturing conditions was conducted. The results show that：（1）The established mathematical model reconstructed THM coupling relationships，modified the functional relationships between fracture porosity/permeability and stress，and improved the variations of CO₂ density，viscosity，and specific heat capacity with pressure and temperature.（2）Considering the thermal compensation effects of bedrock，cap rock，and surrounding rock，a multi-source thermal compensation numerical simulation method was proposed，and a numerical model for CO 2-EGS hot dry rock reservoir development via horizontal wells under multi-cluster fracturing conditions was established.（3）Using the numerical model，the evolutions of the temperature field，seepage field，and stress field of hot dry rock were discussed，revealing that the horizontal well patterns，the configuration of multicluster fracture networks，and the properties of supercritical CO₂ directly influence the evolution process of CO₂- EGS.（4）The controlling factors for CO₂-EGS hot dry rock reservoir development via horizontal wells were identified as the THM coupling mechanism，horizontal well pattern parameters，and multi-cluster fracture network parameters. Compared with TH coupling，THM coupling increases the produced fluid mass flow rate by 5.76%， shortens the heat extraction period by 3.3 years. The reasonable horizontal well pattern parameters are one injection well and two production wells，with a horizontal well length of 1 250 m，and a well spacing of 300 m. While the optimal fracture network parameters are a fracture spacing of 75 m，fracture width of 3 mm，and fracture height of 40 m.

In recent years, well Dongba 1 in Penglai Gasfield in central and northern Sichuan Basin has obtained industrial gas flow through testing in Cambrian Longwangmiao Formation. Based on relevant data such as core samples, thin sections, cathodoluminescence, conventional logging, imaging logging, and geochemical information, the reservoir characteristics, genesis, and distribution patterns of Longwangmiao Formation in Penglai Gasfield, northern central Sichuan Basin were systematically studied. The results show that: (1) The high-quality reservoir of Longwangmiao Formation in Penglai Gasfield are mainly composed of oolitic dolomite, followed by doloarenite. The reservoir space is primarily karst caves, needle-like dissolved pores, residual intergranular dissolved pores, and intragranular dissolved pores, accompanied by a few fractures. The overall porosity mainly ranges from 2% to 6%, and permeability is mainly 0.001-1.000 mD, characterized as a low-porosity and low-permeability reservoir. The reservoir types of Longwangmiao Formation can be divided into karst cave type(with an average porosity of 4.2% and permeability of 0.209 mD), dissolved pore type(with an average porosity of 3.6% and permeability of 0.052 mD)and pore type(with an average porosity of 3.0% and permeability of 0.034 mD), with the former two being high-quality reservoirs.(2) The development of high-quality reservoirs is mainly influenced by sedimentary facies, penecontemporaneous meteoric water dissolution, penecontem-poraneous dolomitization, shallow buried bedding karstification, and structural fractures. Among them, shallow buried karstification has significant impact on high-quality reservoirs in the western study area.(3) High-quality reservoirs are mainly distributed in the PS15 wellblock in the western region, with thickness generally over 10 m and locally exceeding 30 m. They are also distributed in the PS8-PY1 wellblock in the eastern region, with thickness generally ranging from 8 m to 15 m.

Naiman Sag of Kailu Basin has developed unique trona deposit, which is paragenetically associated with salt and crude oil. Based on the data of seismic, logging data, drilling core laboratory analysis, the lithology assemblage, ore characteristics, deposit features and distribution patterns of the trona deposit in Cretaceous Yixian Formation were clarified. Meanwhile, the genesis and patterns of the deposit were investigated in terms of paleostructure, paleoclimate, sources of ore-forming materials, and their coupling relationships. The research results indicate that: (1) The Yixian Formation deposit of Cretaceous in Naiman Sag is characterized by deep burial, steep dip, fault development, thin individual layers and numerous interbeds. Ore body shape is approximately elliptical, with a north-south distribution direction and a lenticular distribution pattern featuring thickened centers and thinning edges. Two sedimentary sequences are developed: A soda-lake type sequence (mudstone-dolomite → trona → mudstone) dominates the deposit margins, while a saline-lake type sequence (mudstone-dolomite → trona → halite → trona → mudstone) prevails in the central zone. On the plane, trona-saline trona-salt distribute in an annular pattern. (2) The deposits are generally oil-bearing. Within mudstone layers, crude oil occurs in intergranular pores of fine clastics, inter-crystalline pores of clay minerals, fractures, and kerogen. In trona and salt layers, hydrocarbons primarily reside in mineral inter-crystalline pores and fractures, cleavage fractures, inclusions, and lattice defects. (3) The trona deposit in the study area is a ternary coupled mineral model of “paleogeomorphology-paleoclimate-volcanic activity”, the deposition of Yixian Formation constituted a closed lacustrine basin. Sodium ions (Na⁺) were continuously supplied to the basin by sodium-rich andesitic rocks in the periphery. The decomposition of organic-rich mudstone produces considerable CO₂, which increases the concentration of CO₂ in brine. The frequent volcanic activities during the Yanshan period led to the upwelling of deep-seated hydrothermal fluids and mantle-derived gas through faults, providing a large amount of CO₂ and Na⁺ -rich hydrothermal fluid. A persistent arid climate towards the end of Yixian Formation resulted in extreme concentration of the lake water, reaching saturation and precipitating trona or halite. Subsequent diagenesis formed the present trona deposit.

Using time-frequency electromagnetic method, residual magnetic force, and high-precision 3D seismic data, combined with data from drilling, logging, well testing, and laboratory analysis, Carboniferous volcanic reservoir characteristics of the eastern Junggar Basin were studied. And distribution zones of favorable reservoirs were predicted through numerical model analysis. The results show that: (1) Multiple thrust faults are developed in Carboniferous of the eastern Junggar Basin, presenting an overall tectonic framework of alternating uplifts and sags interconnected by faults. Denudation mostly occurs in the positions of uplifts. Volcanic reservoirs mainly distribute in Jimusar Sag, Jinan Sag, Fukang Sag, and Gucheng Sag. Lithologies are mainly basalt, andesite, rhyolite, and volcanic clastic breccia.(2) Carboniferous volcanic oil and gas reservoirs in the study area are characterized by a fissure-type volcanic eruption mechanism, with dominant lithofacies being explosive facies and effusive facies. The explosive facies mainly distribute in the central area, while the effusive facies mainly distribute in the eastern and northern areas, showing a linear or banded distribution in the plane, which has a good matching relationship with the fault distribution.(3) The development of volcanic reservoirs in the study area is controlled by weathering and leaching, lithofacies assemblage, and fracture development degree, with weathering and leaching being the main factor. The reservoirs are closer to the top interface of Carboniferous, their physical properties are better.(4) The favorable reservoirs in the study area are mainly volcanic breccia of nearvent explosive facies, andesite and basalt of effusive facies, mainly distributed in the western, central, and southeastern parts of the study area. Among them, the physical properties of volcanic reservoirs in the paleogeomorphic high-lying parts and slope zones in the western area are the best.

Based on core thin section analysis，X-ray diffraction analysis and logging data，the reservoir structure characteristics and main control factors of the M oilfield median buried hill and the BZ19-6 low buried hill in Bohai Sea area were studied. The results show that：（1）Longitudinally，the weathering zone reservoir in M oilfield median buried hill reservoir is well developed，and the pore-fracture type is dominant. The fractures in BZ19-6 low buried hill reservoir are particularly developed，and the weathering zone and the inner zone are dominated by fractured reservoirs. There are obvious differences in burial depth，source-reservoir contact and vertical zonation among different types of buried hill，lead to the differences in the microstructure of reservoirs in terms of pore throat space.（2）Multi-stage tectonic movement causes the differences in the zonation of different types buried hill reservoirs，paleogeomorphological structure restricts the plane distribution of buried hill reservoirs and the migration direction of organic acids，and weathering leaching indirectly improves the reservoir structure of different types of buried hills，and its improvement degree is controlled by buried hill fractures and weathering environment.（3）Different types of buried hill high quality reservoir development zone，have different characteristics. The BZ19-6 low buried hills high quality reservoirs are mainly concentrated in the deep inner fracture zone，and the M oilfield median buried hills are mainly distributed in the weathering zone at the top of the buried hills.

Sequence characteristics and structural combination characteristics of faults of the oil and gas bearing strata of Paleogene Pinghu-Baoshi Formation in the northern section of Baochu slope zone of Xihu Sag in East China Sea Basin were studied by using drilling core，logging and 3D seismic data. The paleogeomorphology was restored through DepoSpace sedimentary domain modeling and sequence stratigraphic boundary difference method. Based on the dip attribute of paleogeomorphology，the types of slope breaks were quantitatively classified，and the sand control mechanisms of different types of slope breaks were explored. The results show that： （1）Paleogene Baoshi-Pinghu Formation in the northern section of Baochu slope zone in Xihu Sag was divided into three structural zones from west to east： the Jinlong Mountain，Longyi Mountain，and Yuanlong Mountain. 7 thirdorder sequences have been identified，with 3 in Baoshi Formation and 4 in Pinghu Formation. In the research area，faults develop and can be divided into 5 fault combination patterns， such as sliding fault step，parallel fault step，graben barrier combination，flower like structure，and“Y” -shaped combination.（2）The slope break in the research area can be classified into fault slope break（level Ⅰ），landforms slope break（level Ⅱ）and sedimentary slope break（level Ⅲ）. The sand control mechanisms of the 3 types of slope break are different. Fault slope break is significantly affected by structural fault，landforms slope break is affected by both structural bending and sedimentary transformation，while sedimentary slope break is mainly affected by sedimentary erosion. （3）4 types of sand control patterns develop in the research area，including fault-landforms slope break broom shaped sand control pattern of the graben barrier fault combination of Jinlong Mountain，landforms-sedimentary slope break sand control pattern of Longyi-Yuanlong Mountain，multi-stage broken step fault slope break sand control pattern of Longyi-Yuanlong Mountain，parallel fault trough fault slope break sand control pattern of Jinlong-Yuanlong Mountain.（4）In the research area， the slope breaks control the development of sedimentary bodies. The footwall of level Ⅰ slope breaks often develop landslide deposits with distant landslides，the footwall of level Ⅱ slope breaks develop steep slope deposits，and the footwall of level Ⅲ slope breaks develop gentle slope deposits. Branch waterways often flow through the area with smaller slope angles on level Ⅱ and Ⅲ slope breaks， and they are prone to form slope fans at the foot of level Ⅰ and Ⅱ slope breaks when flow through them.

Conventional inversion techniques yield low prediction accuracy for reservoirs with low well density， thin single-layer thickness，and strong heterogeneity. A multi-level sparse regularization inversion method based on seismic frequency division was proposed using matching pursuit and Wigner-Ville distribution time-frequency methods，sparse theory，and Bayesian theory. The model data was tested and the inversion method was applied in the reservoir prediction of the second member of Dongying Formation in Shijiutuo Uplift of Bozhong Sag.The results show that： （1）The main idea of seismic frequency division multi-level sparse regularization inversion is to use the Matching Persuit Wigner-Ville distribution technique（MP-WVD）to decompose seismic signals into large，medium，and small scale frequency bands. Based on that，Bayesian theory is employed to construct a multi-scale sparse inversion objective function，applying L2，L1，and L0 norm constraints to the large，medium，and small scale inversion processes，respectively.A hierarchical iterative strategy is adopted： the largescale inversion results as prior constraints for the medium-scale inversion，and then the medium-scale inversion results as prior constraints for the small-scale inversion，with the final inversion result derived from the smallscale inversion.（2）The model data testing results show that： MP-WVD time-frequency spectrum exhibits stronger energy concentration than continuous wavelet transform（CWT）and S-transform time-frequency spectra， with higher resolution in both time and frequency directions，effectively overcoming the cross-term interference issue present in the WVD transform.（3）The application of seismic frequency division multi-level sparse regularization inversion in the reservoir waves of the second member of Paleogene Dongying Formation in Shijutuo Uplift of Bozhong Sag shows that： the results of the P-wave impedance inversion are in good agreement with the sonic log-derived acoustic impedance. It also provides higher resolution than the sparse pulse inversion results， with superior vertical resolution， offering more accurate characterization of thin layers.

Based on TOC testing，rock pyrolysis，casting thin section，scanning electron microscope analysis， the source rocks，reservoirs and hydrocarbon accumulation conditions of Shawan Sag in Junggar Basin were comprehensively studied. The results show that：（1）Triassic Baikouquan Formation in Shawan Sag of Junggar Basin is a gentle slope shallow water retrograding fan delta deposits，and develops two types of favorable sand bodies：fan delta front sand body and shore shallow lake facies coastal sand dam sand body，with the distribution characteristics of horizontal connection and vertical superposition. The lithology is a positive cycle of “coarse at the bottom and fine at the top”. The overall physical properties of the reservoir are ultra-low to low porosity permeability，with an average porosity of 7.8% and an average permeability of 2.38 mD. The physical properties gradually improve from bottom to top，the third member of Baikouquan Formation are with the best physical properties，obviously controlled by sedimentary facies. Moreover，the inhibition of cementation by chlorite cladding，the porosity enlargement by albite dissolution，and the overpressure formed by continuous hydrocarbon injection all have important effects on the development of high-quality reservoirs.（2）Baikouquan Formation reservior has continuous hydrocarbon injection from multiple sets of source rocks（mainly of high-quality source rocks in salt lakes of Fengcheng Formation）. The source-reservoir configuration type can be clasified as vertical configuration and lateral configuration，and their tightness controls the degree of oil and gas enrichment. The subfacies reserviors of fan delta front are widely distributed，with a large area and porosity mostly greater than 15%. It also develops efficient transport system such as high-angle deep faults，unconformity surface，sand body. The overlying regional cap rocks provide superior reservoir conditions.（3）A series of nose-bulges developed along NW direction，close to the source，are favorable structure exploration areas，and the slope break zones are favorable exploration area for lithology.

Taking Permian Emeishan Basalt Formation in southwestern Sichuan Basin as a case study，based on petrological characteristics and nuclear magnetic resonance relaxation mechanism of basic volcanic rocks，the effects of internal magnetic field gradients and paramagnetic mineral content on T₂ spectra were analyzed by using a combination of numerical simulations of internal magnetic field gradients and variable echo time NMR experiments. A new method for characterizing the pore structure of basic volcanic rocks was proposed. The results show that：（1）The volcanic reservoirs in the study area are mainly composed of basalt volcanic clastic lava，calcareous breccia lava，and basaltic rock. The mineral composition of both calcareous breccia lava and basaltic volcanic debris lava is mainly composed of calcite，quartz，plagioclase，and clay minerals. The average mass fractions of clay minerals are 27% and 32%，respectively，with chlorite accounting for 84% and 33% of clay minerals，respectively.（2）The content of paramagnetic minerals（chlorite+iron containing minerals）in basic volcanic rocks is relatively high，which can generate strong internal magnetic field gradients during NMR measurements. Under high internal magnetic field gradient，as echo time increases，the main peak of the T₂ spectrum shifts toward shorter relaxation times，the overall spectrum area gradually decreases，and lead to a smaller nuclear magnetic porosity. The larger the internal magnetic field gradient value，the more distorted the geometric shape of the pores and the smaller the pore size. The internal magnetic field gradient has the greatest impact on calcareous breccia lava，followed by basaltic volcanic debris lava，and has the least impact on diabase porphyry.（3）Establishing a porosity correction formula based on relative error of nuclear magnetic porosity and paramagnetic mineral content through data fitting，converting T₁ spectrum into pore size distribution based on the feature that T₁ measurement is almost not affected by internal gradient magnetic field，establishing the relationship between the geometric mean value of T₁ and T₂ spectrum，correcting the peak shift of the T₂ spectrum，converting T₂ spectrum into pore size distribution，and then T₂ NMR pore structure evaluation can be achieved（. 4）The relative error between nuclear magnetic porosity calculated by this method and the logging porosity is 15%，the relative error of the average pore throat radius between calculated by the method described and from CT digital core experiment is 6%，the distribution of the basic volcanic rocks in the study area are highly heterogeneous，mainly consisting of small and medium-sized pores throats.

In recent years, breakthroughs have been achieved in ultra-deep carbonate oil and gas exploration in Tarim Basin, and hydrocarbons have been discovered across multiple strike-slip fault zones in Shunbei area. Based on seismic profile interpretation, taking the southern section of Shunbei No.5 strike-slip fault zone as an example, the hydrocarbon sources connectivity, transport capacity, and reservoir modification capacity of the strike-slip fault zone were analyzed, and their controlling on hydrocarbon accumulation was discussed. The results show that: (1) Strike-slip fault zones in Shunbei area of Tarim Basin play three crucial roles in ultra-deep carbonate hydrocarbon accumulation: hydrocarbon sources connection, hydrocarbon transport, and reservoir modification. Integrated multiple factors, a semi-quantitative assessment criterion was established to categorize hydrocarbon source connectivity into three types: strong source connectivity, moderate source connectivity, and weak source connectivity. (2) The development of two sets of gypsum salt rock formations (Awatage Formation and Wusongge'er Formation) in Shunbei area has affected the across layer transport of oil and gas. The gypsum salt layer can be classified into three types: escape thinning type, fracture uplift type, and uplift thickening type. The thickness of the gypsum rock layer decreases at the location of strike-slip fault development. When the fault is active, oil and gas easily break through the blockage of the gypsum salt layer and migrate upward. Under the influence of compressive stress, the gypsum salt layer is prone to develop branch faults that intersect with vertical main strike-slip faults, resulting in strata fragment. Oil and gas can be injected into the upper strata of the gypsum layer through small-scale branch faults and fragmented strata, thereby facilitating oil and gas transport. (3) Reservoir spaces in deep carbonate rocks in Shunbei area are mainly caves, vugs, and fractures, which exhibit distinct seismic characteristics of fracture + "beaded reflection", fracture + "chaotic reflection", and fracture + "weak reflection". The reservoirs mainly consist of fractured zones formed by tectonic stress, and subsequently superimposed by deep hydrothermal fluid modification. Fractures can be classified into high-angle fractures, oblique fractures, irregular fractures, and induced fractures. (4) Three enrichment models can be identified in Shunbei area: "strong sourcing-efficient transport-superior reservoir-premium enrichment" "strong sourcing-weak transport-superior reservoir-moderate enrichment" "weak sourcing-weak transport-poor reservoirpoor accumulation".

Significant breakthroughs of shale gas exploration of Cambrian Qiongzhusi Formation in Deyang-Anyue aulacogen and its periphery of Sichuan Basin have obtained，which exhibit substantial exploration potential. Based on data of drilling core，well logging，and seismic profile，a study was conducted on subdivision and distribution characteristics of Qiongzhusi Formation，and the controlling effects of aulacogen paleogeomorphology on sedimentation was deeply analyzed.The results show that：（1）Cambrian Qiongzhusi Formation in DeyangAnyue Sichuan Basin can be divided into eight sub-layers，sub-layers 1，3，5 and 7 are dominated by mudstones， while sub-layers 2，4，6 and 8 are mainly siltstones. Each sub-layer can be accurately identified through sedimentary cycli-city，logging curve characteristics，lithology（color and composition），and biogenic features.（2）The geomorphic units（intratrough deep-water zone，intratrough slope zone，and uplift zone extratrough）within DeyangAnyue sub-layers exert decisive control on the development of Cambrian Qiongzhusi Formation. Qiong-1 Member （sub-layers 1-6）is a filling deposition controlled by a rift trough，with high-value thickness areas in both the north and south，and the sedimentation range gradually expands over time. In contrast，Qiong-2 Member（sublayers 7-8）has transformed into a widespread sedimentation，with high-value thickness areas distinctly shifted eastward.（3）The aulacogen governs the development and distribution of high-quality source rocks from Qiongzhusi Formation. Four organic-rich shale reservoirs（sub-layers 1，3，5，7）and their overlying tight argillaceous siltstone caps（sub-layers 2，4，6，8）form an effective source-reservoir-cap assemblage，with“source-reservoir inversion”accumulation model. Multiple sets of stacked source-reservoir-cap assemblages inside the aulacogen and along its margins dominated the formation of large-scale lithological oil and gas reservoirs in Sinian-Cambrian. High-quality shale reservoirs within the aulacogen and mound-shoal body lithological traps along the trough margin platform zone are the two key targets for next-phase exploration.

Combined with well logging data analysis，mineral composition testing，scanning electron microscopy analysis，thin section observation，pore permeability analysis，nitrogen adsorption testing，and methane adsorption testing，the research of petrological characteristics，physical properties，pore structure characteristics，gas potential，and gas-bearing properties of Ordovician Wulalike Formation shale reservoir in the western margin of Ordos Basin were conducted. The results show that：（1）Ordovician Wulalike Formation in the western margin of Ordos Basin is dominated by dark gray to gray black mud shale，these mud shales exhibit stable distribution and have a thickness of about 78.9 m. The mineral composition is mainly quartz，with a brittle mineral mass fraction of 70.98%-90.32% and a brittleness index of 50.03%-71.16%.（2）The porosity of shale reservoirs in the research area is generally less than 0.1%，and the permeability is generally less than 0.01 mD. The pore types are mainly fractures，nano-micron micropores，and intergranular dissolved pores. The microscopic pore volume is 0.016 27-0.033 73 cm³/g，mainly micropores and mesopores. （3）In the research area，main types of organic matter of Wulalike Formation shale are Type Ⅰ and Type Ⅱ₁，and TOC can reach to 1.54%，the organic matter is in high maturity to over maturity stage，with a maximum methane adsorption mass volume of 0.99 m³/t under experimental conditions of 30 ℃. The highest shale gas mass volume in logging interpretation is 3.4 m³/t. Compared with typical high-quality shale reservoirs at home and abroad，its organic matter abundance is relatively low，the content of brittle minerals is relatively high，and the gas content is at a moderate level，indicating great potential for shale gas exploration.

Based on core observation，thin section identification，cathodoluminescence analysis，fluid inclusion testing，and U-Pb dating technology，the characteristics of petrology and fluid activities of Middle Permian Qixia Formation in southwestern Sichuan Basin were analyzed.The mineral filling sequence and stages of hydrocarbon accumulation were systematically revealed，and the reservoir formation models were clarified.The results show that： （1）The reservoirs of Permian Qixia Formation in southwestern Sichuan Basin mainly distribute in the Qi-2 Member，mainly composed of fractured-vuggy dolomite reservoirs formed through dissolution modification，followed by limestone reservoirs. The reservoir space is predominantly composed of inherited dissolution pores and fractures，which are mostly filled with calcite（2）Qixia Formation reservoirs in the study area exhibit three stages of mineral filling within the pores and cavities，sequentially developed as follows： The first stage is fine-medium crystalline dolomite（Late Permian，253.0±12.0 Ma），characterized by the development of saline fluid inclusions，reflecting low-temperature hydrothermal activity during Late Permian tectonic uplift. The second stage is saddle shaped dolomite（Early Triassic，244.2±9.5 Ma），coexisting with medium to high maturity blue-green fluorescent hydrocarbon inclusions and saline fluid inclusions，with homogenization temperature of 110-115 ℃， indicating hydrothermal fluid and crude oil joint filling during the early stage of Indosinian movement. The third stage is medium-crystalline calcite（Late Jurassic，158.0±38.0 Ma），accompanied by high maturity blue fluorescent oil inclusions and high-temperature saline fluid inclusions，with homogenization temperature of 180-185 ℃，corresponding to the secondary migration of deep crude oil driven by Yanshanian tectonic thermal events. （3）Qixia Formation hydrocarbon reservoir in the study area are mixed-source supply of hydrocarbons formed by two sets of source rocks from Cambrian Qiongzhusi Formation and Middle Permian. The hydrocarbon accumulation process have experienced two key charging stages，namely the initial charging of hydrocarbons in Early Triassic to form the paleo-oil reservoir and the re-charging of deep crude oil in Late Jurassic to adjust and shape the paleo-oil reservoir.

The deep to ultra-deep oil and gas exploration of Mazhong structural belt in Mahu Sag has gradually become a hot field in Junggar Basin. Based on organic geochemical analysis data of rock cores and hightemperature thermal simulation experiments，the organic matter abundance（TOC），hydrocarbon generation potential（S₁ + S₂），hydrogen index（HI）of Permian Fengcheng Formation source rocks in Mazhong structural belt of Mahu Sag were systematically analyzed，and the hydrocarbon conversion rate and gas generation potential of the source rocks were estimated.The results show that：（1）The average TOC of Permian Fengcheng Formation source rocks in Mazhong structural belt is 1.2%，the average hydrocarbon generation potential（S₁ + S₂）is 5.6 mg/g， and the average hydrogen index（HI）is 380 mg/g.The hydrocarbon conversion rate of organic matter is high upto 90%，mainly for oil generation，with a cumulative oil production rate of 829 mg/g. The cumulative gas production rate during the high-mature to over-mature stage is 40 mL/g，and the gas production is relatively low，accounting for only 4.3% of the total hydrocarbon generation.（2）The structural formation period of Mahu and Mabei anticlines is earlier than the main hydrocarbon generation and expulsion period of Fengcheng Formation source rocks，and the reservoir properties were poor，with weak intensity of oil and gas charging.（3）The burial depth of source rocks in Mahu anticline is generally greater than 6 000 m（R_o greater than 1.6%），and hydrocarbon generation has basically stagnated. Moreover，a lack of temperature and pressure conditions for crude oil cracking into gas results in insufficient gas supply and a lack of material basis for forming large-scale gas reservoirs. The burial depth of Mabei anticline is relatively shallow，and the surrounding source rocks are in the mature to high mature stage（R_o being 1.0%-1.5%），which has the potential to form tight light oil reservoirs.

Based on the data of drilling，logging and core，the characteristics and formation mechanism of Triassic Chang 8 tight sandstone reservoir in Huanqing area of Ordos Basin were analyzed by thin section observation，mercury intrusion experiment，nuclear magnetic resonance，then the main controlling factors for enrichment of tight oil were clarified. The results show that：（1）Chang 8 tight sandstone reservoir in Huanqing area is mainly composed of lithic feldspar sandstone and feldspar lithic sandstone，with low compositional maturity （average 0.97）. The main reservoir space types are secondary pores，and intragranular pores and kaolinite intergranular pores can be seen . The porosity ranges from 5.50% to 12.60%，with an average value of 9.50%. The permeability ranges from 0.09 mD to 3.43 mD，with an average value of 0.79 mD. The reservoir is commonly of small pore throat radius，with an average pore throat radius of 0.12-0.16 um and the maximum pore throat radius of 0.49-0.62 μm. The high permeability is mainly contributed by the large pore throat.（2）The evolution about diagenetic and reservoir of Chang 8 reservoir in the study area are as follow. In the early diagenetic stage A，calcareous cemented tight sandstone was formed by injection of calcareous carbonate supersaturated pressure release water into sandy sediments，and the cementation was mainly calcite. In the middle diagenetic stage A，the organic acid fluid was injected into the tight sandstone along the hydrocarbon generation pressurized fracture to dissolve calcite cementation and feldspar detrital particles，and some of the reservoir space were formed.（3）The formation of Chang 8 tight oil reservoirs are controlled by slope background，high-quality source rocks，largescale distribution of river sand bodies and good source-reservoir configuration.The oil and gas are concentrated in the tight sandstone reservoirs close to the source rocks，and the sandstone with large thickness has a better oily content.

Coal-rock gas in Permian Longtan Formation of Sichuan Basin exhibits a wide distribution range， with great resource potential. Based on macro-distribution of coal rock，and comprehensive analysis of organic geochemical，physical property-pore structure，and isothermal adsorption experiments of rock cores，the reservoir characteristics of coal-rock gas in Permian Longtan Formation of Suining-Hejiang area were studied，and its exploration prospects were evaluated. The results show that： （1）Coal rock of Longtan Formation in Suining-Hejiang area is deposited under shore-swamp environment. The coal rock is characterized by large total thickness， multiple layers， and thin single layer thickness. The main coal group is C17-20 coal， with a thickness of 1.0-5.9 m， and the single layer thickness of the main coal seam is 1.0-4.5 m.（2）Coal rock in the study area is mainly bright coal and semi-bright coal， with good coal structure， high vitrinite content and low ash content.（3）The physical properties of the coal-rock reservoirs are good，and the organic pores and inorganic pores are synergistically developed. A lot of micropores and microcracks are beneficial to the adsorption of coal-rock gas， reservoir transformation and gas seepage. The total gas content of coal rock in the study area is high，with a mass volume of 16.4-30.5 m³/t，and of which free gas accounts for 25.8%-37.1% of the total gas content. Within a certain range of buried depth， both the total gas content and free gas proportion increase with the increase of buried depth.（4）The coal-rock reservoir-cap assemblages of Longtan Formation in the study area develop well， mainly develop coal-mud assemblage and coal-sand assemblage. The coal-mud assemblage is with the best reservoir formation condition. Highyield wells have confirmed that the study area has good exploration prospects for coal-rock gas exploration. It is predicted that the favorable area of coal-rock gas is 6 431 km²， with the resource of 2.53×10⁸ m³.

To solve the problem of fine evaluation of microfractures in limestone reservoirs，based on the prin‐ciple of acoustic propagation，acoustic physical experiments were carried out under different fracture conditions （fracture dip angle and fracture aperture），and a characterization model of fracture parameters was established to quantitatively analyze the effects of fracture inclination and fracture opening on shear wave attenuation. The model has been applied to the first member of the Paleogene Shahejie Formation in Caofeidian area，Bohai Bay Basin. The experimental results show that：（1）Five groups of artificial fracture cores with different inclinations， including 0，25°，40°，55° and 70°，are designed in the acoustic physics experiment of microfracture cores in limestone reservoirs. 9 PET films of 25 μm，50 μm，100 μm，150 μm，200 μm，300 μm，400 μm，500 μm and 1 000 μm were used as 9 different fracture aperture degrees. The acoustic wave frequency was maintained at 250 kHz，and the transverse wave waveform under 9 fracture aperture conditions was measured for 5 groups of cores respectively. 32 channels of waveform data were continuously collected for each group of experiments，and the optimal waveform signal was obtained by filtering 32 channels of waveform through noise filtering program and superposition.（2）The acoustic physical test results show that the shear wave attenuation is greatly affected by fractures，and the attenuation trend gradually slows down with the increase of fracture aperture. The attenuation coefficient increases logarithmically with the increase of fracture aperture. When the fracture aperture is less than or equal to 300μm，the attenuation coefficient is more sensitive. Under the condition of the same fracture aperture degree，the shear wave attenuation coefficient decreases with the increase of fracture dip angle when the fracture dip angle is 0-40°，and increases with the increase of fracture dip angle when the fracture dip angle is greater than 40°.（3）The fracture parameter characterization model（Formula 3）is obtained based on the core physical experiment.（4）The relative error of fracture opening degree obtained by the fracture parameter characterization model in the first member of Paleogene Shahejie Formation in Caofeidian area of Bohai Bay Basin is 4.57% and the mean absolute deviation is 18.9 μm，indicating a high agreement.

In consideration of homogeneous reservoirs with stress sensitivity and changing wellbore storage effects of wellbore fluids，oil-gas two-phase flow well testing model of horizontal wells was established， typical well testing sample curves were drawn， and the sensitivity of related parameters was analyzed. The results show that： （1）Applying mathematical methods such as Laplace transform，Duhamel principle，perturbation transform and Stehfest numerical inversion to seek the solution of establied model， numerical solution in real space was obtained.（2）According to well testing theory curves obtained from established model，four main flow stages can be identified： changing well storage and skin effect influence stage，early-time radial flow stage，horizontal well linear flow stage，and late-time pseudo-radial flow stage.（3）Changing wellbore storage effects influence the early-time seepage stage， total conductivity capacity becomes greater as changing wellbore storage coefficient increase. The length of horizontal well influences the early-time linear flow stage， the discharge area enlarges and the bottomhole pressure drop amplitude decreases when the horizontal well becomes longer. The stress sensitivity influence the late-time radial flow stage，as the stress sensitivity coefficient increases，the drop amplitude in permeability also increases. The flow resistance of oil and gas two-phase flow increase while oil saturation become bigger.（4）Using established model to match the measured pressure buildup well testing data，with high fitting accuracy and good consistency between the interpreted reservoir parameters and geological knowledge， the accuracy of the established model is verified.

Based on structural characteristics and sand body geometry features，the structural-lithologic trap types of Cretaceous in Longhupao Oilfield of Songliao Basin were identified and classified by utilizing data from rock cores，master logging，well logging，and production dynamics. The main controlling factors for reservoir formation were studied from three aspects，such as source rock conditions，oil source transport fault，and the relationship between structure and sand body configuration. Oil and gas accumulation models of different types of traps were summarized. The results show that：（1）Cretaceous structural-lithologic traps in Longhupao Oilfield are mainly developed in Putaohua oil layer，with three microfacies ，such as underwater distributary channels，estuary bar，and front sheet sands，which maintain the characteristics of thin and narrow sand bodies in the delta front subfacies controlled by the northern source.（2）The structural-lithologic traps in the study area can be divided into three categories：fault-lithologic traps in the western slope zone，nose shaped structural-lithologic traps in the eastern nose shaped structural zone，and fault-nose shaped structural-lithologic traps in the central subsag zone. They can be further subdivided into eight subtypes：fault-strip sand type，fault-sheet sand type， fault-lens sand type，nose shaped structural-strip sand type，nose shaped structural-sheet sand type，nose shaped structural-lens sand type，fault nose-strip sand type，and fault nose-sheet sand type.（3）The formation of structural-lithologic traps in the study area is jointly controlled by“source-fault-reservoir-potential”. Source rocks from the first member of Qingshankou Formation provide sufficient oil and gas resources，oil source faults serve as vertical migration pathways for oil and gas，and the relationship between structure and sand body configuration controls the enrichment of oil and gas within traps.（4）There are three types of structural-lithologic trap accumulation models developed in the study area：fault-lithologic trap accumulation model of“vertical transport of oil source faults and enrichment of favorable sedimentary microfacies”，nose shaped structure-lithologic trap accumulation model of“lateral transport of sand bodies and enrichment of positive structures”，and faultnose shaped structure-lithologic trap accumulation model of“fault and sand composite transport，and enrichment of connected sand bodies or thick sand bodies”.

Permian Wujiaping Formation in Nanya area of eastern Sichuan Basin has obtained high-yield industrial gas flow，which shows great shale gas exploration potential in the study area. Based on the characteristics of regional tectonic evolution，combined with drilling，logging，and seismic data，the structural features and their control over the generation，storage，and preservation of shale gas were analyzed. The results show that：（1）Nanya syncline area in eastern Sichuan Basin has undergone three tectonic movements，shaping the current pattern of barriertype fold belts. Faults can be classified into 5 levels，level Ⅰ faults in NE-SW direction are the main ones，with a fzult space greater than 300 m. This type of fault has a significant destructive effect on shale gas preservation. （2）“Kaijiang-Liangping”trough，formed by extensional stress provides a favorable location for the formation of deep-water shelf facies shale in the study area. Tectonic movements cause uplift and subsidence of the strata， directly affecting the thermal evolution of organic matter within the shale. The primary hydrocarbon expulsion period occurred during Jurassic，while the main gas generation phase was the early period of Middle Jurassic-Early Cretaceous.（3）The micro-fractures and nano-scale pores formed by tectonic activity provide storage space for shale gas. The reticular fracture system matches the direction of the maximum horizontal principal stress，effectively improving the physical properties of shale and facilitating the migration and enrichment of shale gas. Faults are the main channels for the escape of shale gas，and the preservation of shale gas is mainly affected by level Ⅰ faults. The deployment of well locations should be at least 1.5 km away from level I faults.（4）Tectonic activity has an important impact on the generation，storage，and preservation of shale gas，and“moderate structural transformation，effective reticular fractures，and complete sealing system”are the key factors for shale gas reservoir formation. Nanya syncline area is a favorable area for shale gas exploration in eastern Sichuan Basin.

Through a"three-step"complex network fracture seismic comprehensive prediction technology, the seismic quantitative prediction of fracture development intensity and scale in different orientations and phases of the tight sandstone"fault-fracture body"reservoir of Xujiahe Formation in northern Sichuan Basin was carried out.The results show that: (1) The technical workflow of seismic prediction is as follows: Utilize high-resolution frequency-division ant tracking based on deconvolution generalized S-transform, to predict fracture phases and orientations by constructing a discrete grid model. Establish QVAZ equation for azimuthal attenuation elastic impedance based on the theory of attenuation anisotropy, and combine group sparse inversion to achieve prestack quantitative prediction of fracture density. Integrating the above two technologies for complementary advantages and overlapping analysis, complete the spatial description of complex network fractures.(2) The fractures in the "fault-fracture body" tight sandstone reservoir of Triassic Xujiahe Formation in Tongjiang area of northern Sichuan Basin mainly develop near faults, and their direction align with fault trends. These fractures are mainly of tectonic origin, local anticlines strata display relatively stable development. The tensional fractures associated with the folding process are not the sweet spots of the "fault-fracture body"reservoir, but the intersection of multiple large-scale fractures is a favorable area for the development of complex network fractures.(3) This method can perform high-definition identification of low sequence level faults, reducing the impact of low signal-to-noise ratio and lithological mutations in complex structural areas, avoiding the false appearance of fractures that may be caused by local stratigraphic folds, reducing the dependence of traditional methods on seismic data signal-to-noise ratio, and predicted interlayer micro-fractures with high resolution. The predicted results are in good agreement with the FMI interpretation and testing productivity of actual drilling. Based on this method, the newly deployed well M15 obtained industrial gas flow of 10.35×10⁴ m³/d in the fourth member of Xujiahe Formation during gas testing.

The geological structures and pressure systems of Cretaceous Yageliemu Formation in Kelasu structural belt of Kuqa piedmont are complex. The development of natural fractures has significant impacts on the reservoir flow capacity. Focused on evaluation effectiveness of fracture reservoirs from Cretaceous Yageliemu Formation， permeability sensitive parameters such as fracture width，stress-fracture angle difference，and friction coefficient were optimized to establish a fracture effectiveness index（FEI）classification standard based on in-situ stress through multi-parameter coupling. The results show that：（1）The permeability boundary between effective fractures（unfilled or semi-filled）and ineffective fractures（fully filled）of reservoirs from Cretaceous Yageliemu Formation is around 0.2 mD. Increasing fracture width can improve the reservoir permeability.（2）High stressfracture angle differences and high normal stress reduce fracture effectiveness by influencing fracture closure. While high friction coefficients improve fracture effectiveness by increasing shear slip between fracture surfaces. （3）Based on the weights of various in-situ stress parameters that affect the fracture effectiveness，the FEI evaluation standard was established. Applying this FEI evaluation standard to classify and evaluate the reservoirs in the study area，the proportion of Class Ⅰ and Class Ⅱ effective fractures in the central part of the study area is higher， indicating better reservoir effectiveness. Towards the east and west，the proportion of such fractures decreases， resulting in poorer reservoir effectiveness.

Based on the identification of Permian-Jurassic unconformity in Junggar Basin，the erosion amount was estimated through a combination of stratigraphic trend analysis and sedimentation rate methods. Then paleogeomorphology was characterized using impression method，and the impact of ancient landform evolution characteristics on oil and gas accumulation was analyzed. The results show that：（1）Three first-order unconformities（C/P，P/T，J/K）and three second-order unconformities（P₁/P₂，P₂/P₃，T/J）can be identified in PermianJurassic of Junggar Basin. The denudation area of Permian is mainly located in the southeast and northwest of Zhongguai uplift and Dabasong uplift，with a small amount of denudation in the eastern uplift zone. The denudation area of Triassic is mainly located in the northwest margin of the basin，while the denudation area of Jurassic is mainly located in Chepaizi-Mosowan paleo-uplift and the eastern part of the basin.（2）In the study area，Early Permian showed fault depression，normal faults controlled the west and the strata terminated，the eastern strata overlaid on the slope，and Middle-Late Permian presented a multi-depositional center pattern of uplift and depression. Triassic experienced overall subsidence，with three relatively large sedimentary centers. In Early-Middle Jurassic period，the terrain was flat with minimal topographical fluctuations. During Middle-Late Jurassic，the southern part of the basin experienced severe subsidence due to tectonic activity，resulting in a topography characterized by high in the north and low in the south.（3）The evolution of Permian-Jurassic paleogeomorphology in the study area has a significant influence on the distribution of sand bodies and source rocks. The source rocks developed in the sedimentary center of Lower Permian basin and the glutenite in the uplift area formed a good near source source-reservoir combination. During Middle Permian，the rapid eastward expansion and the pattern of multiple sedimentary centers provided favorable conditions for the development of source rocks. The paleouplifts at the basin margin in Upper Permian significantly controlled the distribution of sand bodies. In Triassic， rapid basin subsidence led to the formation of a deep-water lake basin，depositing a thick layer of source rocks. The flat terrain during Middle-Lower Jurassic provided favorable conditions for coal seam development.

Upper Permian Leping Formation of Pingle Depression is an important coal measure strata in south China， with favorable conditions for the formation of coal measure shale gas reservoirs. Mineral composition， organic geochemical characteristics， pore types， pore structure， and influencing factors of pore development of Leping Formation coal measure shale reservoir in the west section of Pingle Depression were studied through testing methods， such as thin section identification， X-ray diffraction， organic geochemical analysis， scanning electron microscopy， high-pressure mercury intrusion， low-temperature N₂ and CO₂ adsorption， and exploration prospects of shale gas were explored. The results show that： （1） The coal measure shale of Permian Leping Formation in Pingle Depression of Lower Yangtze region is mainly composed of detrital grain， mud and charcoal， with high content of brittle minerals and good fracability. TOC content of coal measures shale is relatively high， kerogen types are Ⅱ₁ and Ⅲ， and thermal evolution reaches high maturity to over maturity stage. （2） The porosity of shale is mostly 3.75%-4.67%， and the permeability is 0.006 2-0.009 1 mD， with low-porosity and low-permeability characteristics. The pore types are mainly intergranular pores， intragranular pores and microcracks， with fewer organic pores. （3） Average pore volume of shale is 0.020 2 cm³/g， average specific surface area is 15.02 m²/g. Mesopores contribute the most to the total pore volume， while micropores contribute the most to the total specific surface area. The pore size is characterized by “multi-peak” distribution. （4） Quartz and carbonate minerals can promote the development of mesopore and inhibit the development of micropores. The increase of quartz content reduces pore heterogeneity， and the increase of carbonate minerals improves pore heterogeneity. Clay minerals and organic matter can promote micropores development and inhibit mesopore development. Clay minerals increase pore heterogeneity， while organic matter strengthens pore homogeneity. （5） The coal measure shale in the study area exhibit good fracability， hydrocarbon generation potential， reservoir capacity， and with good preservation conditions. Yang-qiao， Fengcheng， Fujiaxu， and Taiyangxu are selected as favorable areas for coal measures shale gas exploration， with Fengcheng area being the primary target for further exploration.

Based on core observations of hand specimens，rock thin section identification，well logging data analysis，and seismic profile interpretation，the petrological characteristics，sedimentary facies distribution，reservoir characteristics，and source-reservoir configuration relationship of the fourth member of Sinian Dengying Formation in the west part of Deyang-Anyue Rift of Sichuan Basin were characterized，and the main controlling factors for reservoir formation and hydrocarbon accumulation were clarified. The results show that：（1）The fourth member of Dengying Formation in the west part of Deyang-Anyue Rift develop two subfacies：restricted platform and platform margin. The restricted platform subfacies can be further divided into three microfacies： mound-shoal，platform flat，and platform depression. The platform margin subfacies can be divided into two microfacies：mound-shoal and inter-shoal sea.（2）High-quality reservoirs of the fourth member of Dengying Formation are mainly composed of the algal grainstone，algal-clotted dolomite，and algal-laminated dolomite in the mound-shoal microfacies. The types of reservoir spaces are diverse，such as pore type，karst cave-pore type，and fracture type，mainly consisting of framework pores，intergranular dissolution pores，intercrystalline pores，intercrystalline dissolution pores，and karst cave. The reservoirs of the fourth member have undergone multistage diagenetic modification，the main destructive diagenetic processes include compaction，cementation，and filling， while the constructive diagenetic process is multiphase dissolution.（3）The main controlling factors for hydrocarbon accumulation in the fourth member of Dengying Formation in the west side of the rift mainly are paleo-rift control on source rocks，lithofacies and karst control on reservoir quality，paleo-uplift control on hydrocarbon accumulation，and late-stage structural control on traps.

Based on the latest core well data， characteristics and hydrocarbon accumulation process of karst reservoir in the 3rd member of Maokou Formation（Ma3）in Hechuan-Tongnan area of central Sichuan Basin were determined through analysis of carbonate rock petrology， inclusion petrography and fluid inclusion homogenization temperature. The controlling factors of reservoir development was clarified，and favorable exploration areas were preliminarily predicted. The results show that： （1）In Hechuan-Tongnan area，the reservoir lithology of Ma3 is dominated by bright crystalline-muddy microcrystalline bioclastic limestone，with reservoir spaces characterized by structural enlarged dissolution fracture-vug and pore. Formed fracture-vug karst reservoir is characterized by ultra-low porosity and ultra-low permeability，mainly composed of fractures，with an average porosity of 2.04% and an average permeability of 0.210 mD.（2）Three stages of mineral filling are developed in Ma3 of the research area，from early to late，which are intergranular cemented powder-fine crystal calcite，fracture-vug filling finemedium crystal calcite，and fracture-vug filling medium-coarse crystal calcite. The homogenization temperatures of fluid inclusions developed in the three stages mineral filling are 90-106 ℃，111-136 ℃ and 173-193 ℃，respectively. There are three stages of hydrocarbon filling and accumulation，including the Late Triassic paleo-oil reservoir formation period，early Jurassic paleo-hydrocarbon reservoir formation period，and Middle-Late Jurassic cracked paleo-gas reservoir formation period.（3）The development of karst reservoir in Ma3 is jointly controlled by epigenetic karstification and tectonic fracture activity. The favorable area of karst and tectonic overlap in reservoir development is 2 139 km²， mainly distributed in the central part of the study area.

Based on drilling, logging，2D and 3D seismic，core analysis，well tie comparison and seismic inversion，the research of hydrocarbon reservoirs in Yongjin Oilfield of Jurissic Xishanyao Formation in Monan Slope of Junggar Basin was carried out. The main controlling factors of hydrocarbon accumulation and enrichment of Monan Slope were analyzed from perspectives of sequence stratigraphy，sedimentary system，trap conditions and transportation system，and favorable zones were predicted. The results show that：（1）Jurassic Xishanyao Formation in Monan Slope of Junggar Basin is a third-order sequence，which has undergone a process of progradationretrogradation.The red mudstone developed across time at the top boundary of Jurassic in Monan Slope is widely distributed throughout the area，and can be used as a regional cap rock.（2）The high-quality sand bodies are developed on large scale in the third member of Jurassic Xishanyao Formation.The beach sand in the inner leading edge and the shore-face sand bar in the outer leading edge of the wave-dominated delta are effective reserviors. The internal mudstone serves as the top and bottom plates，lake-bay mudstone laterally seals，providing a superior conditions for the development of lithologic traps.（3）The Indosinian-Yanshanian strike-slip faults connect deep oil sources and can serve as oil source faults. During the Himalayan，low-angle large-scale thrusting nappe faults horizontally developed and transported oil and gas upward，serving as favorable channels for hydrocarbon migration.（4）The intersection of the shore-face sand dam trap zones in the outer leading edge of the wave-dominated delta in the third member of Xishanyao Formation in the north of Monan Slope and the Dadonggou fault zones of Himalayan is favorable zone for further exploration.

Pore throat structure is a key factor that affects the reservoir and seepage capacity of tight sandstone reservoirs, and its fine characterization is very important for the exploration and development of tight reservoirs. The pore throat structure and fractal characteristics of the tight sandstone reservoir of Triassic Chang 8 member in Fuxian area of Ordos Basin were studied by various testing methods, such as casting thin section, physical property analysis, and mercury pressure. The influence of pore throat structure on reservoir physical property were clarified. The results show that: (1) Pore types of tight sandstone in Triassic Chang 8 member in Fuxian area of Ordos Basin are mainly dissolved intergranular pores and feldspar dissolved pores, while throat types are mainly lamellar and curved lamellar. According to the displacement pressure, average pore throat radius, and maximum pore throat radius, reservoirs are classified as three categories. From type Ⅰ to type Ⅲ reservoirs, pore sorting and connectivity gradually deteriorate, pore throat radius gradually decrease, and the pore throat full aperture is 0.001-10.000 μm.(2) The pore throat structures of the three types of reservoirs in the research area all have triple fractal characteristics, with large-scale pore throats (D₁) > mesoscale pore throats (D₂) > small-scale pore throats (D₃). Larg-scale pore throats have complex pore throat networks and relative large fractal dimensions due to strong dissolution, while small-scale pore throats have regular morphology and relative small fractal dimensions due to strong compaction. According to the weighted results, the total fractal dimension(D_T) of the pore throats ranges from 2.05 to 2.44, with an average value of 2.26. From type Ⅰ to type Ⅲ reservoirs, the average D_T gradually increases, and the heterogeneity of the pore throats gradually strengthens.(3) The permeability of Chang 8 tight sandstone reservoir is mainly controlled by the average throat radius. D_T, D₁ and D₃ are negatively correlated with average pore throat radius, reservoir porosity and permeability, and positively correlated with displacement pressure and sorting coefficient, indicating that the more complex pore throat structure results the poorer pore connectivity, sorting and reservoir physical properties. The correlation of D₁ with porosity and permeability is the best, indicating that the physical properties of Chang 8 reservoir are mainly affected by large-scale pore throat. Reservoirs with larger average throats, higher proportion of large pores, and lower fractal dimension are of higher quality.

With Cambrian Qiongzhusi Formation shale of well ZX01 in Zizhong area of Sichuan Basin as the case study, a new method was proposed to identify laminatedion developed intervals and bedding structures by extracting the equivalent micro-conductivity curve (EC) from FMI images to construct a lamination concentration curve(LC). LC curves response characteristics of shale bedding structures were discussed, and the application effectiveness of the LC curve in lithofacies identification and shale gas"sweet spot"evaluation was analyzed. The results show that: (1) An improved Criminisi algorithm was used to restore FMI dynamic images, extract the EC curve from the restored images, perform spectral analysis on the curve, compare the frequency distribution differences between laminated intervals and massive intervals, and perform Fourier band-pass filtering to obtain a laminar signal-enhanced curve. Absolute value and envelope processing were then applied to derive a curve (LC) reflecting the degree of laminar development.(2) Laminated intervals in the first member of Qiongzhusi Formation in the study area mainly distribute in sub-layers 1, 3 and 5, with LC values generally greater than 0.16. LC values of bedded structures are below 0.16, while LC values of massive structures are the lowest.(3) When using machine learning models for shale lithofacies identification, incorporating the LC curve as a feature input improved lithofacies recognition accuracy by 3%. The LC value exhibits positive correlations with TOC, brittleness index, free gas content, and adsorbed gas content, and exhibits a weak negative correlation with porosity. Higher LC values indicate more developed laminations, higher TOC content, and higher brittle mineral content. During hydraulic fracturing, intervals with higher brittleness index are more conducive to fracture propagation, and the development of superimposed laminations can form a complex fracture network system, which increase shale gas well productivity.

Comprehensively utilizing overpressure logging response characteristics，basin numerical simulation， fluid inclusion analysis，drilled core observation，and thin section identification，combined with the analysis of geological conditions for natural gas accumulation，the overpressure characteristics and genesis mechanism of Miocene Meishan Formation gas reservoir in Ledong-Lingshui Sag of the deep water area in Qiongdongnan Basin were analyzed. The coupling relationship between reservoir strong overpressure formation and natural gas accumulation process was explored，and the reservoir formation mode was clarified. The results show that： （1）The pressure of Meishan Formation in Ledong-Lingshui Sag ranges from 49.74 to 95.76 MPa，with a pressure coefficient of 1.37-2.09，which is overpressure-strong overpressure. The pressure structure of a single well shows a typical double-layer overpressure structure. In the early stage，overpressure was mainly controlled by un‐dercompaction，while in the late stage，it was jointly controlled by hydrocarbon fluid pressurization and undercompaction.（2）Natural gas in the study area is jointly sourced by Oligocene and Miocene source rocks，with three stages of oil and gas charging. The first stage（6.0 Ma）was liquid hydrocarbon charging，the second stage （2.7 Ma）was hydrocarbon gas charging，and the peak period of reservoir formation was 1.9-1.0 Ma. The third stage（1.8-1.2 Ma）was CO₂ charging.（3）The strong overpressure in Meishan Formation reservoir in the study area is closely related to the process of natural gas migration and accumulation. Overpressure provides a key driving force for oil and gas migration，which is conducive to the formation of pressure relief channels，such as fractures and microcracks. The multi-stage injection of hydrocarbon containing acidic fluids leads to organic acid dissolution and transformation，effectively promoting the development of secondary dissolution pores. Late overpressure has a positive impact on the preservation of reservoir pores. Meishan Formation natural gas reservoir has the characteristics of“multi-source hydrocarbon supply-overpressure drive-vertical fracture transport-multistage filling-large sand body aggregation-preferential enrichment of near source overpressure dissolution type reservoirs”

To address the challenges in interpreting oil saturation in low resistivity reservoirs using conventional electrical logging methods, an evaluation method based on a random forest optimization algorithm was proposed, and was applied in low resistivity reservoirs of Jurassic Yan’an Formation, Huanqing area, Ordos Basin. The results show that: (1) An oil saturation interpretation model was established using random forest regression algorithm, the Nutcracker Optimizer Algorithm (NOA) was introduced to optimize the hyperparameter tuning of the random forest. By integrating core and logging data through machine learning training, an NOA-optimized random forest saturation model (NOA-RF) was established. (2) NOA method accelerates the training speed of the random forest model, it takes 26.17 minutes to identify the globally optimal hyperparameter combination,which is 36.18 minutes faster than conventional grid search. It also improves the fitting accuracy of the oil saturation model by 96.6%, outperforming grid search by 83.9% and Archie’s method by 45.2%. (3) NOA-RF model achieved a correlation coefficient up to 0.977 9 between predicted and core actual oil saturation in Huanqing area low resistivity reservoirs, with oil-water layer identification accuracy of 93.33%, representing 53.33% improvement over Archie’s method.

The geological structure，formation and evolution of the aulacogen， and its control on the accumulation and distribution of oil and gas are the key issues in the study of rift basins，which are of great significance for deep and ultra-deep oil and gas exploration in craton basins. Based on the study of the geological structure and oil-gas geological conditions of the typical aulacogen in Dnieper-Donets Basin（DDB），combined with statistics of oil and gas fields in the basin， the oil-gas accumulation conditions of the DDB were explored by using seismic and drilling data. The results show that： （1）The syngenetic rift period in the DDB controlled the development of the source-reservoir combination.The folds and faults developed in the post-rift period are the key to the trap formation.The salt structures（salt diapir and salt flow movement，etc.）not only facilitate the migration and accumulation of oil and gas，but also ensure the sealing of the cap rock.There are two oil-gas accumulation models： fault-controlled oil（gas）migration and accumulation； salt structure-related oil（gas）accumulation.（2） The oil and gas resources in the basin are mainly stored in Carboniferous-Lower Permian.Horizontally controlled by faults，it is concentrated in the central fault zone of the basin，while it is more scattered in the north-south fault terrace zone. On the whole，oil and gas are distributed in a belt along the fault zone and its surrounding areas， showing the distribution characteristics of gas production in the southeast and oil production in the northwest. （3）The syngenetic rift period sedimentary structure of the aulacogen has great potential. The fault zone has strong controlling effects on hydrocarbon migration and accumulation， and spatial distribution of oil and gas. As an important area of deep to ultra-deep oil and gas exploration in craton basin，the aulacogen can be a key direction for future research and exploration.