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 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.

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%.

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．

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.

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.

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.

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.

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.

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.

 

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.

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.

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.

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.

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.

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．

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.

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.

Shale gas reservoir has low permeability, in which fluid hardly flow and wells have smaller production capacity. The production decline trend of shale gas reservoir is largely different from conventional gas reservoir. The study on shale gas production decline trend is a reference to predict future production changes, development indices and indicators, subsequent adjustment of development measures. Based on Arps decline equation and generalized Weng’s model, a new model, compound decline model was proposed. Because the compound decline model has more general applicability rather than Arps decline equation, it was applied to shale gas production decline trend analysis in this paper for the first time. Then the changing parameters and influencing factors of compound decline model and Arps decline equation used on shale gas production were computed and analyzed. Comparing the compound decline model with the Arps decline equation in case of practical application in Haynesville shale and Barnett shale, it was tested and verified that there are great differences between the production decline trends of two categories of shale gas field.

Currently, the high water cut oilfield in eastern China have met many technical bottleneck problems that underground oil-water systems need to be rebuilt and well-patter need to be improved further. Based on the development data from 47 foreign high water cut sandstone oilfields, the waterflood development characteristics of foreign high water cut oilfields were summarized, and the redevelopment techniques and measures in high water cut stage of them were analyzed in detail. Furthermore, the new theories and technologies on geology, reservoir engineering and technology were also discussed. These measures adopted in foreign high water cut sandstone oilfields can provide certain guidance for improving waterflood recovery efficiency in similar oilfield of eastern China.

 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.

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.

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 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.

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.

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.

Velocity es timation and modeling technique is a key issue in exploration seismic. As a typical inversion problem, velocity estimation should be carried out under the framework of Bayesian estimation. However, a series of techniques for velocity analysis and modeling are developed by the petroleumindustry. In viewof the present situation of research and application of velocity estimation and modeling technique, we try to analyze the current velocity estimation methods under the framework of Bayesian estimation. All the existing velocity estimation methods can be incorporated into the following two objective functions: the best correlation criterion （the best focusing criterion） in the image-domain or the least error criterion in the data-domain. The gradient-guided local optimization method and Monte Claro method can be used to estimate the seismic velocity in different scales. Under this framework, we can analyze the common features of all the currentmethods, and develop new methods and techniques for velocity estimation.

Shale oil is liquid hydrocarbon reserved in effective argillaceous source rocks with free phase, adsorbed and dissolved phase. Recent years, America has achieved great success in commercial shale oil production, whereas shale oil research in China is still in its infancy with more related theory innovations. Based on shale oil characteristics and experience of American shale oil exploration and development, this paper analyzed and summarized the research progress and some significant cognition in shale oil forming conditions, reservoir features, accumulation mechanism and evaluation method at home and abroad. The systematical comparison of shale oil characteristics between China and America shows that Chinese shale oil mainly deposited in semi-deep and deep lacustrine, and black shale spreads widely, featured by great thickness, complex structures with frequent sandy interbedding. Preferable shale rich in organic matter usually coexists with other lithologies in laminated texture, and the kerogen type of organic matter is predominantly sapropelic with R_o of 0.5%～1.2% and TOC more than 2.0%. Relative high content of fine-grained carbonate and clay exceeding 50% results in a poor reserving capacity. Hydrocarbon-generation condition and reserving capacity significantly control lacustrine shale oil accumulation, simultaneously with additional preserving conditions taken into account in strong tectonic activity areas, such as in the rifted basins. Mixed-type and fractured-type shale oil overall have a huge exploration potential, and the matrix-type follows. In order to promote shale oil research and realize shale oil production earlier in China, the fundamental researches should be on the basis of theories study, and prominently focus on hydrocarbon occurrence, micro pore structure, retained oil accumulation mechanism, structurepreserving condition, evaluation system and resource evaluation method. The purpose of these studies is to provide theoretical guidance for the high efficient exploitation of shale oil in China.

The lateral prediction becomes more difficult because of the strong heterogeneity of carbonate reservoir. A measurement is presented in this paper, which determines seismic response of reservoir by horizon calibration of two-step method and seismic interpretation, predicts the distribution characters of carbonate reservoir with analysing many different kinds of seismic characters including amplitude,frequency, signal-to-noise ratio, and especially waveform, and delineates favorable reservoir zones inTazhong A area.

Carbonate seismic reservoir is a branch subject of seismic reservoir．The particularity，research approach， content，method and key techniques of carbonate seismic reservoir are briefly expounded．And it is proposed that carbonate seismic reservoir is the key of great breakthrough for carbonate reservoir exploration and development，which will promote the development of carbonate reservoir exploration．

The generation of hydrate has brought a lot of difficulties in processes such as gas extraction, gas gathering and so on. The establishment of forecasting model is a puzzle in hydrate prevention and cure. The advantages and disadvantages of four commonly used forecasting model are summarized. The statistical thermodynamics principle is used to establish gas hydrate forecasting model, and five main factors that affect gas hydrate formation are analyzed, including the gas composition, temperature and pressure, ion concentration, acidic gas and inhibitor added. This forecasting model is applied in Luojiazhai gas reservoir, and the result shows that the predictive values are consistent with the experimental results. The establishment of gas hydrate forecasting model is significant for hydrate prevention and guiding gas production.

Based on the analysis of 230 inclusion samples of the second and fourth members of Xujiahe Formation in Hexingchang area, the characteristics of hydrocarbon inclusion and hydrocarbon-bearing salt water inclusion combining with burial history are used to define the gas reservoir formation time. The process of hydrocarbon accumu-lation in the study area is as following：The two main peak homogenization temperatures of the fourth member of Xujiahe Formation ranges from 77 ℃ to 98 ℃ and from 118 ℃ to 120 ℃ respectively, and the corresponding hydrocarbon accumu-lation stages are middle-late stage of Middle Jurassic and middle stage of Late Jurassic, with the former as the main accumulation stage; The main peak homogenization temperatures of the second member of Xujiahe Formation ranges from 95 ℃ to 106.1 ℃, from 119.8 ℃ to 127.1 ℃ and from 134.5℃ to 140.1 ℃ respectively, and the corresponding hydrocarbon accumulation stages are from the late stage of Late Triassic to the early stage of Early Jurassic and late stage ofMiddle Jurassic.

Based on the mathematical and physical theory of wave equation, the full waveform inversion, travel-time tomography, least squares migration and migration velocity analysis can be included into a same inversion frame. Based on Bayes theory, this paper analyzed and compared these methods. It is proved that the full waveform inversion can use most seismic information, but the overlying of different information increases the difficulty of its usage. Under the guidance of signature waveform inversion, the characterized information were extracted to carry out seismic inversion, and several schemes were analyzed and compared theoretically.

Alarge number of experimental and field data showthat starting pressure gradient exists in low permeability reservoirs and fracture is more sensitive than the matrix for stress. Based on dual porosity/dual permeability Darcy seepage flow mathematical model, pressure gradient and stress sensitivity are introduced. A seepage flow model in fractured low permeability reservoir is established, and a full-implicit simultaneous solving and examples calculation are carried out.

Exploration is a kind of creative activity. Cultivating creativity is very important for strengthening searching ability in exploration. The author considers that setting up strategic target and to pic and satisfying high-level demands,such as dedication to the work, are good for inspiring creativity. Building up a better collective environment may benefit creativity development, and strengthening self-cultivation could improve creativity.

Low frequency noise is the main problem of the pre-stack reverse-time migration section. The figure noise removal mechanism based on Laplacian operator and the raising mechanism of the pre-stack reverse-time migration are analyzed. Laplacian operators are used to carry out the pre-stack reverse-time noise suppressing experiments in stacking image domain, common imaging domain and common shot domain respectively, and the results are compared with highpass filter method. The numerical simulation results show that the low-frequency reverse-time migration noise is mainly caused by the inaccuracy of migration velocity, and other reasons of low-frequency reverse-time migration noise are the inconsistency of wavelet form between numerical simulating wavelet and numerical records and the application of the correlation type reverse-time imaging condition. The noise suppressing effects based on the Laplacian operator in the above different domains are obvious, and the result in common shot domain is the best. The above methods in three domains are better than that of the conventional high-pass filter method, the formation detail characteristics of the processed section are clearer, and the horizontal cophasal axes of the common imaging gather are correctly depicted.