The main target for oil and gas exploration of strongly compressional faulted fold zone should be focused on anticline trap. Based on comparison and analysis of the present oil and gas exploration activities mounted in the thrust belts on the northern and southern peripheries of Tianshan Mountain and in the southern and northern segments of Longmen Mountain as well as Chuandong high steep anticline, it is concluded that major oil and gas discoveries are closely related to desirable anticline traps and good storage conditions in the areas with the similar structural characteristics and geological conditions. Buried anticline is good both for trap type and storage condition. The domestic oil and gas exploration practice in the past decades indicates that buried anticline is far better than surface anticline in terms of the number of oil and gas fields (reservoirs), reserves and production in strongly compressional faulted fold zone, with a further rising trend at the current time. Therefore, buried anticline has an important and irreplaceable position in oil and gas exploration of strongly compressional faulted fold zone and should draw attention from exploration experts. Oil and gas exploration of strongly compressional faulted fold zone should follow the principle of òsearching the underground relatively simple buried anticline from the complicated surface anticline,ó thus achieving satisfactory exploration results and bringing exploration activities under good cyclic periods.

Based on analysis of geological structural pattern of Qikou Depression and Combined with structural dynamic mechanism, this article focuses on the influences of the depression on the conducting system and reservoir system as well as its influences on oil and gas accumulations. The results indicate that the NW-SE Paleogene complex fault graben structure and the N-S complex duplex fault graben structure of Qikou Depression were mainly controlled by Cangdong extensional fault system and Qikou extensional fault system, forming Paleo-landform pattern on the plane with a multiple of convexes and concaves and creating favorable space for development of lithological oil and gas reservoirs. The influences exerted by the structural pattern of Qikou Depression on controlling oil and gas accumulations can be found in such ways: When oil and gas were migrating, the main faults controlled oil and gas accumulations while the secondary faults transformed oil and gas distribution, forming the advantageous conducting systems. Favorable reservoir belts, structural slope breaking belts and favorable traps developed at the time of oil and gas accumulations. Based on the previous studies of oil and gas accumulations model, four patterns of accumulations were summarized as follows: steep slope accumulations model, gentle slope accumulations model, stairsbroken near-source accumulations model, and basin-inside slope breaking accumulations model. With exploration targets optimized, good results were achieved in the actual drilling efforts.

N¹² formation of Wunan Oil Field is a set of sand-shale thin interbedding deposit, forming some sand sheets and lenticular bodies. Those sand bodies are the main target horizons of Wunan Oil Field. The grain size of reservoir rock is relatively fine, mainly fine sand and fine sandstone. Calcite of rock is well cemented and high in content. The diagenetic stage of the studied reservoir is from the late A period of early diagenesis to the early B period of early diagenesis. Hydrocarbon source rock released a large amount of organic acid in the late A period of early diagenesis, forming the secondary porous development zone in the sandstone. The reservoirs pores are mainly residual intergranular pores and intergranular dissolved pores. The physical properties of reservoir are poor. The porosity of the reservoir is low to super-low while the permeability is super-low to ultra-low, belonging to the scope of compact sandstone. Thanks to the effect of compactness on the mudstone and sandstone interbedding under the background of saline lake basin sedimentation, the fluids were drained into sandstone from mudstone, leading to cementation of calcite in the rock. This is the main factor for rock compactness in the research zone.

This article elaborates the petroleum characteristics and reservoir types of the Paleogene-Neogene half graben-like rifts in the eastern part of China mainly in terms of six aspects-fault system, types of structural trap, distributed formations, contact relations, types of sand body, and basement. Deep sag belt is elaborated not only as sourcing area but also as reservoir area. Based on the analysis, rift basin is divided into single-rift type and dual-rift type. Each single-rift depression can be divided into three secondary structural units-steep slope belt, deep sag belt and gentle slope belt. The article focuses on the development conditions and distribution laws for various subtle oil and gas reservoirs in deep sag belts where there are no l

Model method, reflection method and tomographic method are common datum static correction methods at the present time. Summarization and analysis of the fundamental principles of various static correction methods and applicable conditions indicate the precondition that all of them are based on the surface consistency and vertical penetration of near surface by seismic reflection. However, under the complicated geological conditions, particularly in the region where static correction of long wavelength exists, it is difficult to meet the assumption of surface consistency. In fact, when the abnormal zone of velocity exists, seismic waves seldom propagate vertically. The distance for the statics and rays to go through near surface is closely related to the velocity. In reflection seismic exploration, far and near offset reflection waves can generate different statics at the time of penetrating near surface. If this phenomenon is used as a principle for to judge the abnormality of target formation as the abnormality of near surface, the problem of long wavelength static correction in the abnormal zone of surface can be solved. This article elaborates on this method, which has desirably solved the static correction problem caused by the near surface abnormality since it was used for production.

Exploration degree is high in Jizhong Depression. Nearly all large-scale buried hills suitable for exploration and with small buried depth have been brought under exploration. However, exploration degree is relatively low for deep buried hills, which have a great potential for exploration and become the main exploration field at the present time. To improve the quality of seismic data and imaging precision for deep buried hills and meet the demand for exploration of super-deep subtle oil and gas reservoirs, the study has been made in light of the characteristics of deep buried hills and their inner curtains, such as large buried depth, strong subtleness, serious attenuation of seismic wave energy absorption, complicated seismic wave field, low signal-noise ratio and resolution of data, difficulty of imaging, strong heterogeneity of reservoir, difficult identification of the shapes of buried hills and their inner curtain traps. The study led to development of four key technologies-wide-azimuth high-intensity acquisition technique, low-frequency acquisition and processing technique based on target formation response frequency, technique of combining time domain with seismic exploration, and technique of quantitatively predicting heterogeneity of carbonate rock reservoir. Those technologies significantly improved the energy of seismic data and signal-noise ratio with abundant lowfrequency information and good imaging results. Deep buried hills and their inner curtain faults became clearer while the shapes of traps are easier to be identified. Good exploration results were achieved at the same time.

To solve the bottlenecks of He-3 sandstone reservoirs of Sulige Gas Field, such as thin thickness and small differential of wave impedance of effective reservoirs and enclosing rock, the prestack inversion and AVO property analysis technologies are adopted to acquire the elastic parameters of reservoirs after the sensitive parameters of reservoirs are determined by logging petrophysical analysis, thus predicting the lithological characters, physical properties and gas-bearing characteristics of reservoirs. The study indicates that the horizontal wave impedance and Poisson?s ratio of this zone can be used to effectively identify the lithological characters. The intersection point of vertical wave impedance and Poisson?s ratio and the intersection point of elastic impedance of different angles can be used to predict the gas-bearing properties of reservoir, improving the accuracy of reservoir prediction and success rate of drilling wells.

With exploration continually unfolding in Liaohe Oilfield, the demand for 3D seismic data, high-resolution 3D seismic data in particular, is higher and higher during the stage of reservoir-aimed oilfield development while its application is more and more extensive. Therefore, it is a realistic task at the 3D seismic data processing stage to use high-resolution processing technology for further improvement of seismic data quality and tap the potential for application of seismic data for reservoir development. The study is aimed to solve some actual problems, such as inadequate resolution of seismic data for the main targets in Ma-19 Block-- Es1, Es2 and Es3, unclear distribution of micro faults, and difficulty in deployment of horizontal well. Based on geological research of the targets and analysis of well data, the study of reservoir-aimed high-resolution processing technology covers five areas, such as amplitude-preserving, expansion of CRP trace gather frequency band, and pre-stack inversion. The processing method sees significant changes as compared to seismic data processing in the previous exploration stage. The study is focused on seismic processing technology for reservoir development of the oil fields for the first time, effectively helping the processing technology extend into the development field. Meanwhile, the study has accumulated precious experience for Liaohe Oilfield to promote fine pre-stack inversion at the next stage.

To solve the imaging bottlenecks in the seismic exploration of complicated structural zones in Bohai Sea region, such as for the secondary fault development zone, high steep structural zone, regional velocity abnormality zone and buried hill inner curtain zone, this article comes up with a technical method which is based on high-resolution velocity model building and uses Gaussian beam depth migration for improvement of complicated structural imaging quality. High-resolution velocity model building is for the purpose to work with TTI velocity model and use high-resolution tomographic inversion technology to obtain more accurate model. Gaussian beam depth migration method is the high-frequency asymptotic time harmonic solution of elastodynamic equation concentrated near rays. It overcomes the shortcomings of standard ray method that the amplitude changes sharply and non-fixedly near the caustic surface. It can also ensure normal response from complicated structures. Actual data processing indicates that joint application of the two technologies improves imaging quality of high steep structures and complicated faults in Bohai Sea region, thus improving the quality of seismic data.

Focusing on the development characteristics of shallow-water multiple in LD zone of Bohai Sea, a complete set of joint shallowwater multiple attenuation technique is proposed in this article. First of all, the SWD approach is used to eliminate most of short-period multiples related to the sea bottom. Secondly, the 2D surface-related multiple suppression approach is used to effectively eliminate the remaining surface-related long-period multiples. Thirdly, the Radon transform is used to separate the residual multiples after 3D harmonization. Finally, the high-precision Radon transforms used to attenuate multiples in the CIP gather after pre-stack time migration. This method reasonably combines the SWD technology with the traditional multiple separation technology to attenuate multiples. Processing of offshore seismic data from Bohai Sea region indicates that the above-mentioned method can effectively attenuate shallow-water multiples. The joint shallow-water multiple attenuation processing technique is fast and simple while the amplitude is well kept after processing of seismic data.

The study is focused on the largest carbonate rock oil and gas field in the southern part of East Siberia -- Yurubcheno-Tokhomskoye Oil and Gas Field. Based on geological and geophysical data and backed by GIS system, the study adopts the comprehensive analysis method for multi-element information to scrutinize the information on the fractures of different sizes in the carbonate rock oil field in the light of fractural origin and development laws. The seismic data are used to identify regional Riphean reservoir development zone and predict fractural development zones caused by structural fractures of different sizes. The Riphean fractural reservoir is brought under comprehensive evaluation for the purposes to determine the principle for classification of reservoir-appraising factors, establish the database of multielement fracture information that influences reservoir development, build thematic map by means of space analysis model, and conduct topological calculation and drawing. The high-yield zone is predicted on the basis of the above-mentioned work in the efforts to make a comprehensive analysis of the information on multi-element fractures of different sizes and space relations. The advantages of this method are to maximize collection of various fractural information, establish a magnitude database of relative information, and facilitate rapid selection and comparison of information and thematic space analysis. This study makes full use of geological characteristics of oil and gas fields and wisdom of experts and optimizes fractural information to effectively serve actual production of oil fields

Lower Congo Basin is one of the hydrocarbon abundant margin basins of West Africa passive continent. With a large number of oil and gas discoveries made particularly in the deepwater zone, the area has become the hot spot for oil and gas exploration. The characteristics of hydrocarbon accumulations in the deepwater zone of the basin are very complicated. Two sets of source rock developed in the area: pre-salt marine and post-salt lacustrine source rock. There are three sets of favorable reservoir-caprock assemblages-deep layer, middle layer and shallow layer. The current exploration has confirmed that the upper Neogene turbidite sandstone and deep Albian carbonate rock reservoirs are the two main targets. Comparatively speaking, the physical properties of reservoirs are good with a desirable matching relation between reservoir and cap-rock. The middle and shallow layer assemblages are mainly the structural-lithological traps while the deep layer assemblage is mainly the near S-N and salt rock-related structural traps. All the elements of the reservoirs are well matched in terms of time and space. Based on the study of the reservoir elements, three favorable accumulations models are established for the post-salt marine source rock and Neogene turbidite sandstone reservoirs, post-salt marine source rock, and Lower Cretaceous carbonate rock reservoirs and pre-salt lacustrine source rock and Lower Cretaceous carbonate rock reservoirs in the deepwater zone of Lower Congo Basin