Despite technological advances in lab instruments, grain-size analysis has many limitations, such as low speed. A theoretical method of determining grain size based on spatial autocorrelation coefficient of simulated rock section was proposed. Firstly, spatial autocorrelation coefficient was obtained from a group of known distribution grain size of rock section. Secondly, an unknown distribution grain size of rock section was used to calculate spatial autocorrelation coefficient. Finally, linear least squares method about spatial autocorrelation coefficient was solved with constrains. In order to show the feasibility and availability of this method, a serial theoretical rock sections were simulated by random ellipse process. Relationship between spatial autocorrelation coefficient and grain size of simulated rock section was analyzed. With the decrease of offset or increase of grain size of rock section, spatial autocorrelation coefficient is increasing. Grain size distribution of simulated rock section was determined accurately. For example, gritstone was separated into 0.5～1.0 mm, 1.0～1.5 mm and 1.5～2.0 mm, whose computed percentages are respectively 55.8%, 24.6% and 20.2% by the proposed method, closing to the actual values, and the variation trend is same as the actual.

The organic-rich shales of the second member of Kongdian Formation （Ek₂） are developed very well in Cangdong Sag, Huanghua Depression. Research on geochemical characteristics of the shales is highly significant for the shale oil resource evaluation. Based on collecting and sorting the research results of predecessors, additional core samples were taken to carry out tests and analysis of organic carbon, rock pyrolysis, chloroform bitumen “A”, kerogen maceral and vitrinite reflectance. Single well numerical simulation of burial and thermal history and geochemical evolution sections were also
studied. Organic-rich shales of Ek₂¹, Ek₂² and Ek₂³ were all evaluated as the best source rocks. The types of organic matterare mainly of ⅠandⅡ₁ , with small amount of Ⅱ₂ and Ⅲ. Immature to low mature shales are mainly distributed in central uplift zone, while the organic-rich shales in slope zones are at low maturity to maturity stage. The organic-rich shales of Ek₂ began to generate and expulse immature to low mature hydrocarbon in early Eocene and reached the peak in the late sedimentary period of Guantao Formation. Then with being continuously buried deeply, the source rocks could entered into
low mature to mature hydrocarbon generation stage and the conversion rates of hydrocarbon generation is as high as 60%.

Aiming at the current status that low salinity water flooding has been applied to pilot test abroad while in China there is little research, this paper analyzed the current research status and existing problems, and proposed prospects for low salinity water flooding. It is concluded that for sand reservoirs, the main mechanisms of low salinity water flooding are similar to alkaline flooding, fines migration and the wettability alteration caused bymulti-component ion exchange, while for carbonate reservoirs, the mechanismof lowsalinitywater flooding is wettability alteration caused bymulti-component ion exchange. Crude oil properties, reservoir rock properties, formation and injected water salinity and reservoir temperature can all influence the effects of low salinity water flooding. The main problems lie in the unclear mechanisms, low salinity water source limitation and reservoir adaptability. Finally, it is pointed out that low salinity water flooding can be combined with current oilfield development techniques, coal bed methane production techniques, development techniques for low permeability oilfield and high water-cut oilfield, which will form new economical, environmental-friendly and great potential techniques for enhanced oil recovery.

The response surface regression analysis technique is an integrative method for optimization procedure. It not only can build continuous curved surface model, but also can form response surface to estimate the interaction of the influence factors, which can make up the shortage of traditional single factor experiment. This technique is firstly applied to carbon dioxide drive numerical simulation, and the influencing factors are analyzed. The good result shows that response surface regression analysis technique can be used for experiment design and analysis in petroleum research.

Based of X-ray analysis, conventional logging data combined with multielement nonlinear regression and grey theory analysis are applied to determine the clay mineral content in the area where is poor in natural gamma ray spectrometry log. The result shows that the method is accurate for determining the clay mineral content, so it can provide theory foundation for reservoir evaluation and sensitivity analysis.

The reservoir classification study is important work for managing scientifically the reservoir and raising the effects of oilfield development．In view of the reservoir characteristic parameters，the reservoirs are classified by cluster analysis method on the basis of the similar relationship of the reservoir features，which overcomes the influence of human factors．According to the attribute value of each category．the discriminant functions are established．The multibank discriminant methods are applied to calculate the probability of the standard type for unknown reservoir,and then the similar degree with the standard one is decided．Thus the type of the unknown reservoir is determined accurately． The result shows that the use of these two kinds of mathematical methods can classify and manage the reservoir scientifically．

Seismite is a type of catastrophic deposits with recognizable evidence for seismic activities and sequence. According to core observation and description, many deformation structures with seismite characteristics are recognized within sandstone and shale sedimentary strata of Paleogene continental faulted basin in Yangxin Subsag, such as micro-faults, earthquake fissures, liquefaction sandstone veins, water-escape structure, vibrational liquefaction deformation structure, seismic pillow structure and associated structure, etc. The vertical sequence of seismites in Yangxin Subsag, in ascending order, is underlying unshocked layer, micro-faults layer, autoclastic shattered breccia layer, vibrational liquefaction deformation structure layer, seismic pillow structure and associated structure layer, liquefied homogeneous layer and overlying unshocked layer, which corresponds to different earthquake intensity respectively. The discovery of seismites can be used to analyze the intensive activity stages of basincontrolling boundary fault, and seismite itself is a kind of potential reservoir, so it has important geological significance for studying earthquake event deposit.

Shale gas is one of unconventional gas resources and stores in organic rich shales and mudstones as free gas and absorbed gas in pores developed in organic matter and mineral matrix. Shale gas accumulation is considered as a cumulative gas charging within organic rich shales, and the organic rich shales serve as gas source, reservoir and seals. The gas origin in shale gas reservoirs could be thermogenic, biogenic or the mixing of both. The feature of low porosity （<10%） and low permeability （μD～nD） in shales requires hydraulic fracturing to enhance pore connectivity for achieving commercial gas production. A success of shale gas development in the United States is a typical model of comprehensive integrating between shale gas geological characterization and petroleum engineering technologies. Shale gas exploration in China is in its early stage but shows a great resource potential. The low-level shale gas survey, immature technologies for shale gas development, unclear understanding of main controlling factors of shale gas reservoirs, the lack of the theory and model of shale gas accumulation are challenging issues for shale gas success in China.

As petroleum exploration goes into a more and more mature stage, deep clastic reservoir is becoming an important new area for exploration in the oil-gas basins. The research of deep petroleum exploration is focusing on the mechanism of the clastic reservoir evolution. The formation mechanism of the deep effective clastic reservoir is complex and closely connected to the sedimentation, diagenesis and tectonism. Sedimentary environment is the prerequisite and foundation for forming effective reservoir. Secondary pore produced by the main constructive digenesis vastly improves reservoir physical properties. Depositional environment and diagenetic conditions that can prevent or slow down diagenesis effectively is conductive to the reservoir physical properties, including low geotemperature, rapid burial history, abnormal pressure, gypsum-salt bed effect, hydrocarbon inject, grain coats and fluid activity, etc. During the evolution of deep reservoirs, tectonic compaction reduces the pore volume, while the structural fractures improve the seepage ability of the reservoir porosity, forming effective fractured reservoir. Thus, the reservoir forming mechanism was suggested with the deposition, dissolution and tectonism being fundamental, key and occasion respectively. Through using modern technology, conducting the diagenesis modeling experiments and using new methods with the inter-discipline knowledge, have already become the main development trends of the research of the forming mechanism of the deep effective clastic reservoir.

With the decarbonization of energy worldwide，natural hydrogen，as a primary energy，has gained widespread interest for its carbon-free emission and renewability. However，natural hydrogen has not yet to be explored in China. Through the review of the main geological settings and genesis of natural hydrogen with a high content（greater than 10%）discovered worldwide，the beneficial geological factors for natural hydrogen accumulation were systematically summarized，and the exploration prospects of natural hydrogen in China were evaluated based on the exploration and development status of natural hydrogen abroad. The results show that：（1）Global high content natural hydrogen is mainly developed in ophiolite belts，rift valley，and Precambrian iron-rich strata，mainly inorganic genesis，and the serpentinization process of iron-rich minerals is the most critical source of natural hydrogen，followed by degassing in the deep earth and water radiolysis.（2）High-quality hydrogen sources and good migration channels are the prerequisites for hydrogen enrichment，and the sealing ability of the cap rocks is a key element for the formation of natural hydrogen reservoirs. When natural hydrogen is used as associated gas，the traditional cap rocks can seal it，but may be difficult to form effective sealing when its content is high. The rift valley environment，ophiolite development areas，and the fracture-developed Precambrian iron-rich strata are the favorable areas for the exploration of hydrogen-rich gas reservoirs.（3）Many countries and regions abroad have formulated plans to explore，develop，and utilize natural hydrogen. Mali has realized commercial exploita‐tion of natural hydrogen，and the United States and Australia have also successfully drilled natural hydrogen ex‐ploration wells.（4）The areas with high hydrogen content in China are highly compatible with hydrogen-rich geological conditions，and the prospects of natural hydrogen exploration are good. The Tan-Lu fault zone and the peripheral rift basin areas，the Altyn fault zone and the basin areas on both sides，and the Sanjiang orogenic beltLongmenshan fault zone and peripheral basin areas have great natural hydrogen exploration potential. China should carry out the survey work of natural hydrogen as soon as possible，strengthen the research on hydrogen reservoir accumulation process and potential evaluation，and carry out research on exploration technology，ex‐traction and separation technology，and storage and transportation technology，to prepare technological reserves for large-scale development and utilization of natural hydrogen.

In order to standardize overseas oil reserves evaluation,a method for classifying and categorizing overseas lithologic reservoir reserves,determining lithologic boundary,o il bearing area and effective thickness was proposed. The results show that:（1）Reserves classified as P generally require a development plan approved by the company or the government of the resources country. P1 reserves are calculated based on wells with commercial production or commercial test flow rates,and their area is usually determined by the drainage area of the production wells and the range limited by the known gas bottom or the known oil top and oil bottom. The reserves within half the distance from the P1 reserves boundary to lithologic boundary are P2 reserves,and the reserves within the range from P2 reserves boundary to lithologic boundary are P3 reserves. If there is no oil water contact within the trap or cannot be determined yet,P3 reserves should be determined based on the spill point of the trap. If there are significant changes in lithologies or reservoir physical properties,P2 reserves can be determined by extrapolating one development well spacing based on P1 reserves,and P3 reserves can be determined by extrapolating one development well spacing based on P2 reserves.（2）When the distance from a class P reserve well to the pinchout line of a permeable reservoir is no more than 3-4 times the development well spacing,for medium to high porosity and permeability reservoirs,the pinchout line can be directly determined as the lithologic boundary,while for low porosity and permeability reservoirs,the minimum effective thickness contour line that can meet the class P reserve standard is determined as the lithologic boundary. The oil and gas bearing area should be comprehensively delineated by lithology boundaries,oil（gas）water contact,tight layer sealing zones,etc,the wells within the area should meet the class P reserve standard. For oil and gas reservoirs with identified fluid interfaces,the fluid interfaces used to delineate oil and gas bearing area should be confirmed by drilling and coring data or testing data. For oil and gas reservoirs with unidentified fluid interfaces,the oil and gas bearing area should be determined by extrapolating the lowest confirmed bottom boundary of the oil and gas producing layer or the effective thickness value through testing.（3）The determination of the effective thickness of P1 reserves should have reliable formation testing data or sufficient logging data and have demonstrated its production capacity. The determination of the effective thickness of P2 reserves usually lacks conclusive testing data and has not confirmed its production capacity. Due to the uncertainty in rock physical interpretation,there is significant uncertainty in the effective thickness of P3 reserves.（4）It is recommended to use the volumetric method for evaluating lithologic reservoir reserves. The application example in TP oilfield in Ecuador has confirmed the effectiveness of the classification and categorization of lithologic reservoir reserves and reserves evaluation method.

By reviewing the development history，main research progress，and development direction of artificial intelligence technology in the field of geophysical exploration（geophysical exploration）both domestically and internationally，the advantages and challenges of intelligent geophysical exploration were summarized，and solutions were proposed. The results show that：（1）Geophysical technology was integrated with artificial intelligence technology in the second wave of artificial intelligence development. Thanks to the exponential growth of data volume in the field of geophysical exploration，the rapid development of hardware computing power，and the emergence of new deep learning frameworks，intelligent geophysical technology has developed from early machine learning to current deep learning，and has achieved a large number of research results in seismic data processing and interpretation.（2）At present，intelligent geophysical technology is widely used in the construction of tag sets，denoising，fault detection，layer and sequence interpretation，seismic facies classification and anomaly detection，lithology identification and reservoir development，and seismic inversion imaging，greatly improving work efficiency，reducing work costs，overcoming the subjectivity and unreliability of manual interaction and experience，and helping to break the bottleneck of traditional geophysical technology.（3）The development of intelligent geophysical technology faces challenges such as a lack of publicly available label datasets，a lack of intelligent frameworks to solve problems in the field of geophysics，and the lack of an intelligent development platform suitable for sharing in the field of geophysics. These challenges can be addressed by addressing data infrastructure，building intelligent platforms，conducting basic research on network architecture，and combining it with application scenarios. In addition，the development direction of intelligent geophysical technology also includes the following aspects：research on intelligent seismic imaging methods，reservoir imaging methods，oil and gas big data mining，intelligent risk assessment and intelligent decision-making，and research and development of supercomputing software equipment.

The exploration and development of shale gas in the U. S. is progressing fast, which also leads to the development of tight oil. Tight oil is the oil accumulating within the shale system, including black shale with very low permeability, argillaceous siltstone and interbeded sandstone. Tight oil can be free oil or absorbed oil. It is a continuous reservoir of self-generation and self-storage. The development of tight oil in the U. S. mainly performed in Bakken, Eagle Ford, and the Barnett shale zone. Bakken shale has oil resource of 230×108 t and recoverable resource of 5.9×10⁸ t. Bakken shale located within the U. S. has oil of 3.7×10⁸ t and similar amount of associated gas. Its cumulative oil production since 2 000 is about 2.8×10⁷ t. Eagle Ford shale produces oil in the northern part, annual oil production of about 2×10⁵ t. Barnett shale has average undiscovered oil resource of 1.4×10⁷ t, ofwhich undiscovered tight oil resource is 4.8×10⁶ t. At present, Barnett shale has more than 8 000 producing wells, mainly produces oil in the northern part, gas in southern part. Up to the end of 2009, the cumulative oil production of “tight oil zone” has reached 7.7×10⁶ t. China is a country rich in black shale. It is expected that the exploration of tight oil will get breakthrough soon.

By using field emission scanning electron microscope, this paper observed and described the size, shape, distribution and seepage characteristics of micropore in dark shale in northern and northwestern Guizhou. Based on the genesis, the pores were divided into three categories: primary sedimentary pores, secondary pores and mixed pores. Based on the development location, the pores were divided into ten sub-categories, such as intergranular pores, intra- crystalline pores, fossiliferous pores, organic matter pores and so on. The influencing factors for the pore development and the pore evolution characteristics of shale were discussed, which has important theoretical and practical significance forthestudyonshalereservoir.

Chang 8 member of Yanchang Formation is the major reservoir in Jiyuan Oilfield. With the development of oil and gas exploration, the areal heterogeneity of the reservoir has become an obstacle for further exploration and development, so the fine sedimentary facies description is particularly significant. Based on the analysis of sediment provenance and facies indicator, it is considered that Chang 8 member ofYanchang Formation is controlled by the provenances fromthe northwest and northeast, experienced the transformation from delta plain to delta front, and deposited distributary channel sand body which is superimposed vertically and continuous laterally. The physical properties of Chang 81 layer under different subfacies and different sources are contrasted. The result shows that the reservoir property of delta plain in Chang 81 layer is better than that of delta front, and the reservoir property controlled by the provenance fromnorthwest is better than that controlled by the provenance from the northeast. The favorable reservoirs of Chang 8 member are predicted, and it is considered that the reservoir in the northwest of Jiyuan Oilfield has great hydrocarbon potential.

In order to solve the problems of low opening rate caused by directional gas channeling in the middle and later stages of CO₂ flooding development in low permeability reservoirs, poor overall development results and potential safety issues, numerical simulation and laboratory experiments were used to analyze the effects of anti-controlled gas channeling, to ensure the production rate of oil wells and other technical methods. The results show that the CO₂ of water-gas alternating is more uniform and the oil recovery efficiency is better than that of gas injection, wheel injection and continuous gas injection. When the monthly CO₂ injection-production ratio is 1.7 to 1.8, it can simultaneously maintain the mixing capacity and prevent gas channeling, so as to decrease water cut and increase oil production. In view of gas channeling characteristics of oil well, different flow pressure control standards were formulated to maximize the CO₂ flooding effect. The pressure field changes can be adjusted by periodic oil recovery, which can increase the frequency of oil and gas contact to promote mixed phase and expand the volume of CO₂. The periodic oil recovery effect of typeⅠgas wells is better than that of type Ⅲ gas wells and the continuous oil recovery. The safety production is effectively guaranteed by adjusting the injection production ratio and controlling the reasonable production pressure difference, installing the wellhead control valve and setting up wellhead single well tank regular pressure relief. The results can provide technical reference for the development of CO₂ flooding test and promotion in Jilin Oilfield and the same kind of oil reservoirs in China.

Deliverability analysis of horizontal well is the basic work of getting economic benefits, and it provides basis for horizontal well optimization, perfecting work system, production dynamic analysis and adjustment. At present, there are twomethods of deliverability calculation for horizontal well, namely analytical method and simulation method. The deliverability prediction methods for conventional horizontal well, multilateral well, fractured horizontal well and horizontal well pattern are summarized. The birth and development of deliverability analysis theory are reviewed, the new advances at home and abroad in the deliverability analysis theory and methods are introduced, the problems exists are expounded, and the development direction is pointed out, which will be helpful for improving the application of horizontal well in oilfield development.

The importance of stratigraphic reservoir exploration is rising day by day on the condition that the field of national oil and gas exploration is transferred fromstructural reservoir to litho-stratigraphic reservoir. On the basis of the former research, this paper centers on the unconformity and classifies the stratigraphic trap into three types: the on- lapping typed trap above the unconformity, the barrier typed trap belowthe unconformity and the truncation type of trap between the former unconformity and the later unconformity according to the difference of trap mechanism. This paper summarizes the formation mechanism of stratigraphic reservoir from the strength and the structure of the unconformity. Furthermore, authors point out the distribution law of different type of stratigraphic reservoirs and exploration suggestion for different type of stratigraphic reservoirs. Finally, this paper points out some theories and techniques which are in great need for stratigraphic reservoir exploration.

Provenance analysis is one of the most important aspects in the research of sedimentary basins, and it is of great significance in studying the relationship and the interaction between basins and hills. At present, lots of experts put forward many kinds of analytic procedure, but they cannot constitute a system. This paper summarized the study ways from four aspects: the determination of source area, the analysis of parent rock features in the source area, the determination of moving path and the tectonic setting of source area, and established a frame of approaches about provenance system. In different sedimentary basins, according to the abundance of geological data, qualitative analysis and quantitative analysis should be combined and many kinds of study ways should be made up for each other. Only in this way, the conclusion of the characteristics of provenance system would be scientific and reasonable.

As the key in the process of reservoir modeling, facies modeling provides reservoir framework for the simulation of the reservoir parameters. Based on the analysis of several commonly used facies modeling, it was presented that using shale content and comprehensive well log interpretation to reconfigure lithofacies in lithofacies modeling, which is available for the work area without sufficient accurate sedimentary microfacies study. The principle and importance of the variogram were expounded. A set of effective methods was suggested referred to the problems occurred in the process of variogram calculation. The effectiveness of these methods has been proved in practice.

Large shallow-water deltas in depression basin contribute to the main potential increase of onshore lithologic reservoirs in China. The Baoqian delta of the Upper Cretaceous in southern Songliao Basin and the modern Ganjiang delta in Poyang Lake were analyzed. The particular focus was put on the paleo-environment, depositional features and growth pattern of this type of delta.(1)Depression basins are favorable for large shallow-water deltas. Unconfined morphology results in the frequent rise and fall of lake-level,which controls the delta dimension in dip direction.(2)There are two different types of deltas in the Upper Cretaceous of southern Songliao Basin. One is deep-water delta characterized by lobe shape and easily-identified depositional facies, mainly including distributary channels,mouth bars,and interdistributary bays. Another is shallow-water delta characterized by bird's foot shape and obscure boundaries between depositional facies,mainly including distributary channels and interdistributary bays,with mouth bar less developed.(3)The remote sensing for modern sedimentary systems reveals the evolution of Ganjiang middle delta in Poyang Lake in recent 50 years,showing the transition from disperse branch shape to connective network shape.(4)Large shallow-water delta in depression basins is a complex consisting of several deltas formed in multi-scenarios. The sand-bodies of distributary channels are the most significant reservoir and carry massive lithologic reservoirs. They are distributed horizontally in a net pattern and control the distribution of lithologic reservoirs.

The formations from the Upper Sinian toMiddle Triassic in Sichuan Basin are marine deposits and mainly composed of carbonate rocks. Through 50 years petroleum exploration, fifteen carbonate gas-bearing beds have been found in the basin. Among them, carbonate rocks of Upper Sinian and Cambrian have been completely dolomitized, and the others also have dolomitization more or less. There are various explanations for the genetic model of dolomite in marine carbonate reservoir in Sichuan Basin, mainly including: protogene, penecontemporaneous, reflux, meteoric-seawater mixing water, burial, hydrothermal fluid, leaching of basalt and biogenesis. Dolomite reservoir is regarded as one of the most important carbonate reservoir, and the dolomitization is the prerequisite for the development of high-quality carbonate reservoirs in Sichuan Basin. The burial dolomitization and meteoric-seawater mixing dolomitization of marine carbonate rocks have been widely queried, and there are two taphrogenesis events and related extensive fluid activities in marine carbonate rocks in Sichaun Basin, so hydrothermal dolomitization could be more widespread than previously thought in Sichuan Basin.

Reservoir microscopic pore structure directly affects the reservoir storage and permeability, so the research on reservoir microscopic pore structure characteristics can help to carry out reasonable classification evaluation of reservoir, and find out reservoir distribution law, improve the productivity and recovery ratio of oil and gas. Based on a large number of relevant literatures, this paper summarized and expounded the origin, test methods, theory research progress and comprehensive evaluation of reservoir microscopic pore structure, analyzed the main existing problems in the research of domestic reservoir microscopic pore structure, and pointed out that the research of the domestic micro structure is mainly based on traditional methods, having the problem of insufficient combination with domestic actual geological condition and lack of quantitative research.

A majority of oil and g as reserves have been discovered that are located in the Mesozoic a nd Cenozoic fault basins of terrestrial facies in eastern China. These basins have different sizes and types with great discrepancy of reserves, whereas most of oil and gas fields that have been discovered and developed are obvious structural trap. With the continual enhancement of Chinese hydrocarbon exploration activity,the difficult increasing and type transferring,the targets of hydrocarbon exploration have been changed to subtle li thologic and stratigraphic trap. Therefore it is much necessary to analyze and research the characteristics of depositional filling at different structural zone during different evolutive phrases in this basin in order to provide geological theories and science evidences for the exploration of lithologic and stratigraphic trap.Dongying Sag belongs to Jiyang Depression of Bohaiwan Basin, which is a typical lake basin of half-garben with the terrestrial coarse clastic deposits. The depositional filling pattern and extensional characteristic of sandstone within Dongying Sag are very representative to study this type of basin.So,the paper emphasized that Dongying Sag has been analyzed from both spatiality and timein the view of sedimentology. A set of corresponding relationship has been expatiated that structural characteristic directly controls the depositional filling characteristics,climate straightly determines the property of deposits, sediment supply and lake-level changes mainly dominate the patterns of spatial depositional filling.The depositional filling model and corresponding relationship in the v arious structural zones during each evolutive stage have finally been summed up. These results can provide help and evidences for hydrocarbon generation and distribution in faul t basin of terrestrial facies.

There are many methods for seismic impedance inversion. Aiming at the methods of generalized linear inversion , the key techniques are discussed here , such as iterative impedance inversion , regularization method , resolution of impedance inversion , the statistic and mean square deviation used to control the inversion quality , secondary smooth filtering and the constrained impedance inversion. And a great of modeling computation are carried out . Referred to the methods of recurrence impedance inversion , the main techniques are analyzed in the aspects of the wavelet and reversed wavelet extraction , the effect of noise on reversed wavelet extraction and so on.

Clay mineral is an important component part of reservoir, and its content and feature have a great effect on oil field development. The identification of the clay mineral types by using natural gamma- ray spectroscopy log method was discussed. The result showed that using natural gamma- ray spectroscopy log could not only identify the types of the clay mineral, but also determine the content of the clay mineral in the reservoir, which could provide effective reference for the development plan of oil field.

The studies on strontium isotope have received rapid development s in all fields of sedimentology, with the continuous development of dissolution technology for strontium isotope samples of marine carbonate, testing method for diagenetic alteration and strontium isotope database of marine sediment s in the period of geologic history. Strontium isotope is applied to carry out the researches in the aspect s of the provenance analysis, dating marine sediments, paleoclimate and paleoenvironment analysis, water-rock interaction and hydrogeochemistry. The latest progress and development t rends in these fields are discussed.

 

The volcanic reservoirs of Carboniferous in Xiquan area of Junggar Basin are characterized by smallscale volcanic body, and the main controlling factors are not clear. On the basis of core observation and thin section identification, combined with logging, analysis and test data, a statistical analysis of the lithologies of Carboniferous in Xiquan area was carried out. The main controlling factors of reservoir physical properties and its distribution law were analyzed. The results show that the lithology in the southern structural belt is mainly composed of andesite, volcanic breccia and tuff, and mainly tuff, sedimentary rock and andesite in the northern structural belt. The reservoir properties in the southern structural belt are obviously better than that in the northern structural belt, of which the main controlling factors are lithology, lithofacies, tectonic movement and weathering leaching. The volcanic facies, such as volcanic breccia and tuff in the southern structural belt, the overflow facies of andesite in the northern structural belt, and their overlap zones with the structure highs and the fracture development, are favorable plays for hydrocarbon exploration.

Taiyuan Formation in eastern Ordos Basin is typical tight sandstone reservoir, with high content of clay minerals, so it has great influence on reservoir evaluation and natural gas exploration. Based on the analysis of petrography and geochemistry, the characteristics and origin of clay minerals of sandstone reservoir of Taiyuan Formation in eastern Ordos Basin were studied. The result shows that the reservoir sandstone of Taiyuan Formation is with high content of clay minerals, which is mainly of illite and kaolinite. The illite is characterized by high content of Al₂O₃ and K₂O and low content of FeO and MgO, and the Al₂O₃ content of kaolinite is more than that of typical kaolinite. Sr/Ba ratio of illite and kaolinite is less than 1. Meanwhile, illte and kaolinte are enriched in LREE, depleted in HREE, characterized by downwards sloping and some extent of δ Eu and δ Ce anomaly. Petrographical and geochemical characteristics show that illites and kaolinites are all related with hydrothermal fluid. Combined with tectonic-burial history and authigenic diagenetic minerals sequences, it is revealed that hydrothermal diagenesis began with the early Cretaceous thermal anomaly in Ordos Basin. Hydrocarbon fluid formed by thermal evolution of coal-bearing source rocks came into reservoir sandstone of Taiyuan Formation, which leads to the hydrothermal alteration to form large quantity of illtes, kaolinites and other authigenic minerals.

Seismic reservoir is a boundary science，which is based on seismic data，geology，logging，drilling，testing，oil extracting and analysis assay data，to study the change of reservoir lithology，appearance characteristics，space types， pr0perties and fluid features in three．dimensional space and build reservoir mode1．Seismic reservoir is suitable for every stages of the hydrocarbon exploration and development．It is under the guidance of sedimentology，reservoir geology and seismology ，and based on the organic combination of seismic data，geology and logging．Logging analysis， seismic reservoir prediction，reservoir fluid prediction，reservoir modeling and 3D visualization are the key technologies for seismic reservoir．The greatest advantage of seismic reservoir is that it extends the reservoir parameters into 3D space in the range of seismic resolution and can'ies out reservoir modeling and 3D visualization．

On the basis of clarifying the conception of reservoirs, according to the history of the research on reservoirs, it is an inevitable course of history that stratigraphic-lithologic reservoirs are regarded as an important part in the petroleum prospecting. The category, genesis and prospecting features of stratigraphic-lithologic reservoirs are summarized, and three typical examples are analyzed.

The evaluation methods of development effect applied in water drive oilfield were evaluated, including states-balance method, systemic dynamic analysis method, fuzzy comprehensive analysis method and grey system method. After analyzing the advantages and shortcomings of each method, it is pointed out that the states-balance method and fuzzy comprehensive analysis method are more suitable for water drive oilfield. The problems and development trend of these evaluation methods in the process of application and research are discussed. The research result has significance on guidance and reference for the optimization and research of evaluation methods for water drive oilfield development effect.

For the requirement of petroleum exploration, logging techniques develop rapidly. Several logging techniques are analyzed. High resolution array induction, microresistivity image well logging, three component induction resistivity logging and cross dipole acoustic logging tool are favorable for the research on formation heterogeneity and anisotropy. Nuclear magnetic resonance logging, cable formation test and sidewall coring improve the recognition of formation fluid. Recently, new logging technique of electrokinetic logging is proposed. The measuring principle and apparatus composition of new techniques from Schlumberger, Halliburton, Atlas, Computalog and Russia are introduced, which is helpful for the development of our current scientific research and production. The current status and difference of the logging technologies in China are discussed, and the developing direction is pointed out.

Seismite is a type of catastrophic deposits. The characteristics and geological significance of seismites are summarized. The rock types, seismic sequences, distinguishing marks of seismites and the contrasts among seismites, tsunamites and seismoturbidites are introduced. Based on the former research, six seismic sequences are proposed, which are composed of seismites, tsunamites, seismoturbidites and background deposits. Seismites take a significant part in the studies on the interpretation of tectonic evolution, sedimentology and reservoir geology.

Based on the mercury penetration analysis of more than 300 samples and analysis result s of more than 260 casts and more than 100 image pores , and referred to the classification criterion about clastic reservoir , especially low permeability reservoir , the low permeability sandstone reservoirs in Ordos Basin were divided into four types and four sub-types. The four types include low permeability reservoir ( I) , extra-low permeability reservoir ( II) , super-low permeability reservoir ( III) and tight reservoir ( IV) . Among them extra-low permeability reservoir and super-low permeability reservoir are the main reservoir types of Triassic Yanchang Formation in Ordos Basin. According to t he characteristics of t he pore structure and petrophysics and the classification criterion of the reservoir thickness , they are divided into two
sub-types respectively.

 In order to study the heterogeneity of shale mineral components, this paper analyzed the CT scanning images of shale by using digital image processing techniques, studied the distribution characteristics of shale mineral components, and discussed the relationship between the content of mineral components and fractal dimension. The research results show that the density of shale mineral components on the CT image is much greater than that of organic matter and micro pore structure, so the mineral components are easy to identify. At the same time, the distribution of shale mineral components have fractal characteristics, showing a certain self-similarity, and the fractal dimension of mineral components can reflect the heterogeneity of mineral components. The study on shale heterogeneity based on CT images is an effective supplement of shale reservoir evaluation, and it can guide the evaluation of shale brittleness.

South Turgay Basin is an important oil-bearing basin in central south Kazakhstan, which is a rift basin of Mesozoic. The struct ure character is grabens separating horsts. Aryskum Trough in the south is the main depression and oil kitchen , including four NW-SE direction grabens from west to east. The oil fields found are located in the arches and slopes. The main genetic unit is Jurassic-Cretaceous series , and several regional unconformities exist through the sediments. Lower-Middle Jurassic mudstones are mainly source rocks, the principal reservoirs are the clastics of the Middle-Upper Jurassic and the Lower Cretaceous Formation, and early Cretaceous mudstone is regional seal. Although during more than 20 years exploration course, most large-size reserves have been found , there are many exploration potential fields. Except for the structure traps, the stratigraphic traps of Jurassic-Cretaceous Formations at the graben flanks and the basement weathered crust of Paleozoic are the future exploration directions.

Aimed at the shortage of classification evaluation for extra- low permeability reservoirs, several new techniques developed in reservoir research are introduced in recent years. Four classification evaluation parameters for extra-low permeability reservoir are proposed, including effective porosity, mainstream throat radius, movable fluid saturation and start-up pressure gradient. The reservoir classification evaluations are carried out to nine blocks. The results show that the seepage capacity and effective reservoir space could be effectively reflected. This classification method will be important to guide the oil/ gas field development.

Compared with general seismic techniques, VSP can remove noise effect more effectively and improve vertical resolution. Combining 3D seismic profile and core, the key layers are calibrated, their relations can be made definitely, and fine seismic attributes analyses is processed. Amore accurate geological model is set up and the reservoir heterogeneous can be made clearly by using VSP image. Taking Nanshanwan area for example, the thin sand of Putaohua oil layer can be recalibrated using VSP time-depth table, and its bottom can be interpreted accurately. The reservoir is predicted by several attributes analyses, and sedimentary facial map is established to put forward favorable exploration targets.

Inspired by the development of shale gas and the decrease of natural gas price, the investors kicked off shale oil exploration and development. U. S. A has been obtained huge benefit from shale oil, and the shale oil resource potential is also huge in China. Based on the previous study on shale oil resource potential of basins in eastern China, the comparative study on geochemical characteristics of shale oil between U. S. A and China has been done. The research results indicate that the oil saturation index（OSI） can be used as an effective index for judging the shale oil intervals, combined with the carbonate mineral content, brittle mineral content and the interbed. The results also show that the OSI values of Jiyang Depression are similar with that of Monterey, Barnett and Eagle Ford shale. At present, the shale oil exploration of China should be aiming at the hybrid type.