Tarim Basin in Early Palaeozoic was not a uniform one, and after then it underwent multi-stage basin formation, multi-stage development, and multi-stage reconstruction. Finally it evolved into an overlay one. As a result, the Lower Palaeozoic of the Basin was characterized by multi-source hydrocarbon generation, multi-stage hydrocarbon generation, multi-stage migration and accumulation, multi-stage reservoir formation and multi-stage reconstruction. The factors controlling the oil-gas reservoir formation of Lower Palaeozoic could be summarized as òsource control, uplift control, slope control, surface control, fault control, and facies controló. Compared to the exploration idea of òselecting zone by determining bottomó of primary type basins of the Mesozoic and Cenozoic era in East China, the exploration idea of Tarim Basin should be òto select zone by determining sourceó. On the basis of confirming effective hydrocarbon kitchen, through the study and determination of fault, unconformable surface, transport layer, and the favorable exploration zone related to hydrocarbon kitchen, the exploration strategy of favorable zone might be determined as òdominated by exploration for oil, gas, or oil and gas simultaneouslyó, according to the thermal evolution degree of source rocks.

Through the research on Permian System on the west slope of Mahu sag in Junggar Basin, it is verified that the dolomite reservoir of Fengcheng Formation is favorable for acquiring large-scale high-quality and high-efficiency reserves. These reservoirs are mainly dolomite siltstone and arenaceous dolomite, formed in stable and low-energy still water environment, where microfractures developed. The development degree of fractures, the layout relationship between dissolved pore and fracture, and the volume of dolomite in reservoirs are key factors influencing whether the quality of reservoirs is good or bad. The area where high-quality reservoir of Permian Fengcheng Formation is generally where the dolomite reservoir of the first member of Fengcheng Formation is horizontally and stably distributed and thick vertically and the gypsum reservoir of the second member of Upper Fengcheng Formation developed. At the same time, the area is located at the fault zone or fracture developing zone.

Qikou sag has more than 40 years of oil/gas exploration history. It has become more and more difficult for exploration, and the development demand is getting more and more urgent. Faced with the new situation, based on the rich resource, Dagang Oilfield emancipated the mind, transformed the exploration idea, advanced òthree wholes, four finenessó exploration procedure, i.e. whole acquisition, whole study, whole evaluation, fine target processing, fine target study, fine scheme design, fine organization and implementation, and strengthened the research and exploration of slope area lithologic reservoirs. As a result, the Oilfield discovered three-hundred-million-tonnage reserves zone in Qibei slope, Chenghai fault developed slope and Binhai fault nasal shape structure and its slope. Some important recognition and experience have been obtained from the exploration practice of slope area lithologic reservoirs. They are of great significance to step up future exploration of the slope area lithologic reservoirs in Dagang Oilfield

Dynamic hydrocarbon accumulation theory is built on the practice of petroleum exploration in China, and is a body of systemabout petroleum exploration which is about the comprehensive evaluation of petroleum geology and the hydrocarbon accumulation and distribution. The theory developed and further improved the pattern of comprehensive petroleum geology evaluation and exploration, from static to dynamic state, from presentation to genesis and motion. This paper proposed the concept of dynamic hydrocarbon accumulation theory and its ideology. Three basic principles (the principle of interaction and relativity, the principle of oil and gas resources and their time-space distribution, and the coordinating and matching principle of trap system and charging system), the new cognitions and analysis methods were described in detail. The system and its features of dynamic and comprehensive evaluation and integrated exploration of petroliferous basins were analyzed based on above theories. At last, according to the history and status of petroleum exploration of Tarim Basin, this paper evaluated the risk composition of petroleum exploration and the optimal target management systems comprehensively.

Surface and subsurface seismic conditions are very complicated in bare carbonate rock area in the south, which is typical karst geomorphology. Surface lithology of the area is mostly limestone and karst, and the conditions for fracture development, excitation and receiving are complicated. As a result, single-shot quality varies a lot and signal-to-noise ratio of acquired data is usually low with different topography and surface conditions. So conventional seismic acquisition methods could not work well. Systematic research was conducted on the designing method for seismic pattern layout of the area, comparing and analyzing advantages and disadvantages of different layout. Through continuous practice, a layout of òwide line+curved line+high fold+long arrangementó was explored, and the survey line was optimized using high-accuracy remote sensing data on the basis of sufficient demonstration. This did not only improve the single-shot excitation and receiving effect, but also enhanced overall quality of seismic data greatly. At the same time, seismic work became easier in the mountain to certain degree. The seismic pattern layout has high adaptability, and expected result of layout optimization was achieved in the area.

Lithology discrimination of volcanics is the basis and key to volcanic reservoir evaluation. Taking the volcanics in Santanghu Basin as example, the volcanics lithology in Carboniferous Kalagang Formation is complicated; lava, volcanoclastic rock, and transition rock developed in the Formation. Aimed at the difficulties in lithology discrimination, on the basis of delinating the rock mass range of volcanics based on regional gravity and magnetic data, physical quantity including gama, resistivity, compensated density, and interval transit time sensitive to lithology is selected; detailed calibration is conducted on core and thin section data. Crossplot is used to set up the log response discrimination mask of volcanics, realizing log lithology discrimination of volcanics and then correcting geological logging lithology precisely. This provides solid basis for volcanics exploration in Santanghu Basin

Along with the exploration and development of oil-rich depressions up-grading to a higher level, the exploration, amid at complex fault-block, lithologic trap, low amplitude structure and thin reservoir, has entered a stage of detailed exploration. Thus, precision requirement of new acquisition seismic data imaging is also getting higher and higher. Up to now, seismic data acquisition in China most uses the array with multiple vibrators. This method will influence the precision of seismic imaging. In this paper, forward modeling and actual field seismic acquisition data analysis showed that vibrators combination had greater impact on the direction of static correction and imaging accuracy of geological bodies. More than one source combination, arranged parallel to the combination, produced relativelysimple error change and strong regularity. This is a relatively good combination. Vibrator portfolio also affects the accuracy of statics. Generally speaking, the smaller the array length, the higher the accuracy of statics

Velocity data is the basis of 3-D velocity field. Making comprehensive use of VSP data, velocity spectrum data and acoustic logging data can help establish a high-precision 3-D velocity field. In the process of 3-D velocity field, surface smooth processing is comparatively troublesome, and the 3-D velocity field after the gridding surface smooth processing usually holds larger storage space. The proposed block polynomial surface fitting method can effectively make up for the deficiency. The 3-D velocity field obtained from this method used in seismic data interpretation horizon calibration could provide more accurate T-D conversion relationship for the well without VSP or seismic log. On horizon calibration work, seismic data interpretation workers can also avoid blindness. This method has been applied in actual oil development and achieved good results

Many gas wells were discovered in Z blocks, and the number of gas layer is larger in single well and the total gas is thick. In the seismic profile, the gas-bearing event features in higher thickness, dropping down and low frequency. There are many reasons for òbright spotó in this area, and the gas and gas-water layer of different saturation is strong in amplitude. Studies suggest that it is not difficult to identify the distinction between the water and gas, but the quantitative prediction of gas saturation. In this paper, based on pre-stack inversion and rock physics analysis, perturbation experiments were conducted to identify the sensitive parameter for saturation and obtained the sensitive parameter and the relationship between the density and saturation. Finally the relationship was used to examine the application effect in overseas oil and gas basins.

East Venezuela Basin is a large asymmetric foreland basin which has rich oil and gas resources. It went through three evolution phases since Paleozoic: rifting phase (late Triassic to Jurassic), passive margin phase (Cretaceous to Eocene) and foreland basin phase (Oligocene to today). Vertical sedimentary strata can be divided into three megasequences: pre-Cretaceous sequence, Cretaceous sequence and post-Cretaceous sequence. Marine shales and carbonates of the Guayuta Group and Tigre Formation are the main oil and gas source rocks in the East Venezuela Basin. The maturity of oil source rock is decreasing from north to south. Oil and gas in the northern hydrocarbon kitchen migrated stepped and long distance to the southern slope edge by faults and sand body. Anticlinal, faulted, stratigraphic and lithologic traps are commonly found in the basin. There are two mainly sets of hydrocarbon plays, structural traps/structuralstratigraphic traps/ stratigraphic traps assemblages in the Oficina Formation and structural traps assemblages in the Naricual Formation. Four potential exploration targets exist in the basin: sedimentary sequence of passive margin from Cretaceous to early Miocene, foredeep of the central basin, heavy oil belt in the southern basin and offshore of the eastern basin.

The passive continental margin basins of South Atlantic Ocean, controlled by the rifting and persistent drifting of South Atlantic Ocean, shared the same regional tectonic evolution background. However, due to the asymmetry and imbalance of the opening of South Atlantic Ocean, the development and hydrocarbon potential of basins of both sides varied. The hydrocarbon of eastern South America concentrated in big-Campos basins, typical passive continental margin basins with integrated developing phases, including prerift, syn-rift, transitional and post-rift phases, and each phase had its own unique features, developing pre-salt and post-salt petroleum systems. Whereas, the hydrocarbon of West Africa focused in Lower Congo Basin and Niger delta. Although the integrated features of Lower Congo Basin looked alike the big-Campos basins, the discrepancies of accumulation elements were still obvious. Besides, from south to north, the evolution phases of basins descended. When coming to Niger delta in the middle ofWest Africa, the Niger delta only experienced syn-rift and post-rift phases, and was dominated by Tertiary petroleum system. This paper focused on the formation and evolution of the major petroliferous basins of South Atlantic Ocean and their control over hydrocarbon accumulation. The comparative study could be used as a guide to screening of strategic petroleum provinces overseas

Africa has rich oil and gas resources, 15 petroleum basins developed in the coast of West Africa, with the exploration area being as high as 3.31 million square kilometers. Three sets of main source rocks and four sets of main reservoirs developed in the basins of the coast, and there are four important exploration domains here, including mature and new ones. The development and violent activity of salt rock and extremely thick mud rock exert great effect on hydrocarbon reservoir formation. Now 2095 oil and gas fields (reservoirs) have been discovered in 15 basins here, and there are still huge resources to be discovered, which are expected to reach 116.9 billion bbl oil equivalent. In recent years, many large oil and gas fields have been discovered in the salt basin group in middle of West Africa, the Niger Delta Basin, and deep water area of Cte d'Ivoire Basin, upholding a vigorous campaign for deep water exploration in West Africa. Viewing from exploration potential and hydrocarbon enrichment degree, West Africa is the most important strategic basin of oil and gas exploration for Chinese oil companies in West Africa. Considering the basic petroleum geologic conditions, exploration degree, exploration potential and other non-geologic factors (such as investment environment, politics and economy, relationship with China, and safety, etc.) based on comparative analysis, it is suggested that Chinese oil companies focus on the deep water area of strike-slip pullapart basin group in middle ofWestAfrica (mainly in Congo Fan Basin and Kwanza Basin), and Niger Delta Basin, and strengthen the study on hydrocarbon reservoir formation conditions and exploration potential in Southwest Africa basin group (mainly the basins in the coast of SouthwestAfrica), northern salt basin group (mainly the Sierra Leone-Liberia Basin and Senegal Basin). The basins mentioned above could be the reserve battleground of Chinese oil companies in West Africa, if they have certain exploration potential.

Rankin Platform is an important gas-condensate prolific zone in the North Carnarvon Basin. The platform has been uplifted in the Early Jurassic, and became a depo-center again in the Cretaceous. The thick Middle and Upper Triassic Mungaroo Formation is an important exploration target in the platform. Although gas accumulations in the platform have been sourced from multiple formations, the Middle and Upper Triassic Mungaroo Formation is the important proved source rock for gas. This source rock generates gas for quite a few reservoir-source rock combinations. Barrow-Dampier sub-basin is the terminal area for hydrocarbon migration. Because the Barrow and Dampier areas receive slightly different hydrocarbons, and the gas discoveries in the north of the platform have more condensate content than those in the south. Well developed structural traps, good seal and multiple source rocks may account for the concentration of gas accumulation in the platform