From analysis of resources distribution types and controlling factors of Quaternary biogas in Sanhu region in Qaidam Basin, three occurrence ways of biogas are pointed out: the low-rate structural traps, the lithologic traps, and the widely distributed water-soluble form. The exploration focus is the North Slope area, the Yanhu-Yabaer area, the low-rate structural traps in the west and sags. The lithologic pinchout traps in the S-N slopes, the low uplifts and slopes in the basin, and the lens in the lake basin are the future exploration targets.Water-soluble natural gas exploration is heuristic exploration direction in the area

Two large volcanic-sedimentary cycles developed in Early Cretaceous in deep Xujiaweizi Fault Depression in Songliao Basin, i.e. the first and third members of Yingcheng Formation. Each volcanic cycle features in multi-period and intermittent eruption, and the volcanic rocks of each period are overlaid spatially. According to the volcanic characteristics, volcanic phase sequence, and rock rhythm combination characteristics, combined with the correlation between sedimentary formations and volcanic rocks at the intermittent period, the first and third members of Yingcheng Formation are divided into three eruption periods, i.e. Yc1 1, Yc1 2, Yc1 3, Yc3 1, Yc3 2, and Yc3 3 from bottom to top. Volcanic rocks of different eruption periods vary a lot in structure, facies, lithological composition, reservoir types, and degree of oil and gas enrichment. The division is of great significance to the identification of the law of regional volcanic activity, the study on distribution of volcanic facies, and the oil and gas distribution and enrichment.

The Zongbayin Sag is subordinate to the depressions in the middle of East Gobi Basin in Mongolia. It is a Meso-Cenozoic sag formed on the Paleozoic fold basement, of which basins are superimposed and depression-faulted of inversion type. The Early Cretaceous rift basins take the majority and they experience four stages of development, i.e., faulted subsidence, faulted inversion, depression subsidence and depression inversion. At the stage of depression inversion at the end of Early Cretaceous, Zongbayin early synsedimentary slope was transformed into thrusting with broken nose, because of the sinistral strike-slip of Zongbayin fault along the arc-shaped cross-section. So the "framework of three bulges and two depressions" of the Zongbayin Sag takes shape now. Same as other sags in the Erlian Basin, the Zongbayin Sag is part of rift basin groups in Northeast Asia. However, it is located in the transitional region of the extensional structures in the east and the compression structures in the west, of which the geotectonic environment is more like the top of the Mongolia arc structures. So there is similarity but with difference between the Zongbayin Sag and other oil-rich sags in the basin. They have similar history of structural development, complex inner structures, NE and NNE fracture system. But they have different basin types and development periods, different sag structure and framework, different causes and formation time of local structures

Lunnan buried hill reservoir is a super large carbonate reservoir, with the relative height 1000~1500m, the acreage 10000km2, and the buried depth 4100m. The main reservoir is the Ordovician carbonate karst weathering crust cracks-cave system. Above the hill, there is a giant thick Ordovician or Carboniferous mudstone onlapped on the slopes as a capping formation, but an area of more than 80km2 in the top is covered by thick Triassic waterbearing sandstone, so a top-window area comes into being. It is just because of the top window that a special type of reservoir is formed, i.e. the topopening buried hill reservoir. In this type of reservoir, oil and gas are mostly accumulated in the slopes surrounding the hill. The upper area near the top is water area or oil/water bearing area. The oil-water interface in the reservoir is tilting, and the oil-gas accumulation has unique hydrodynamic features.

Niuxintuo Sag is the first rifting sag in the west of Liaohe Depression, of which Es4 is the most complete. Faults research shows that the uplift and dextral strike-slip of structural cycles of Eocene and Late Oligocene leads to the formation of reverse faults on the east and west sides of Niuxintuo Sag. A series of extrusion, strike-slip, and extensional faults come into being, different types of structural styles are formed, such as extrusion structure, flower structure, and nasal fracture structure. Fracture determines the distribution of source rocks and reservoirs as well as the oil and gas transporting system. The development characteristics and hydrocarbon potential of different petroliferous zones are determined by different fault zones. So the research on development characteristics of different fault zones is of great significance to the optimization and evaluation of favorable petroliferous zones and traps.

Early Paleogene-Neogene of the Dafeng-Xinghua region has been affected by extensional strike-slip, presenting a structural framework of òearly fault depression and late sagó. Research shows that hydrocarbon accumulation in the region has the laws as follows: the reservoir distribution is controlled by the hydrocarbon-generating center, the scale of reservoirs is determined by the size of sags, to discover good sand bodies is very important because the oil bearing series is single and the individual reservoir is thin and changes fast horizontally, the large fault leading to deep sags is critical to oil and gas migration and now oil reservoirs are located in the vicinity of the large fault. In addition, the activity of most reservoirs with the characteristics of lateral sealing has ceased before source rocks get mature. Structural traps are favorable oil and gas accumulation zones, so structural reservoirs and structural-lithologic reservoirs generated from small complex faults are the main types. Taken together, the main idea of "to discover oil in traps in oilrich sand bodies based on faults" is put forward.

47 large and medium gas fields in China is based on low abundance of reserves, the second is high and middle abundance of reserves, and the least is ultra-low reserves. The method of estimating gas diffusion loss is set up by using the Fick?s law, and the gas diffusion loss of the 47 gas fields is estimated. Results show that the diffusion loss of different gas fields varies a lot. The minimum is only 0.92×108m3, while the maximum is 2286.81× 108m3. The latter is over 2200 times higher than the former. Through the research on the correlation between reserves abundance and diffusion loss of gas in the 47 gas fields, it is shown that the lower gas reserves abundance is, the greater gas diffusion loss gets, and vice versa. Gas diffusion loss is an important cause of the decrease of gas reserves abundance of large and medium gas fields in China.

The zeolite found the southern region of West Qaidam Basin is mostly analcime. Grainy and massive zeolite is distributed in sandstone intergranular holes, cracks, and carbonate emposieu. The zeolite in the region can be formed by both metasomasis and mid-low temperature epithermal deposition. Analcime is distributed in sparry calcite cement, while natrolite is in quartz and feldspar clastic particles. Analcime is distributed in sparry calcite and early calcite cement is wrapped in natrolite cement, which shows that the formation of zeolite is later than that of sparry calcite. Massive zeolite is mainly developed in reservoirs, and mostly in oil and gas bearing intervals

In Hailar basin, the structure of lithological profiles is complex, not only containing volcanic lava and normal sedimentary rocks, but containing transitional volcanic lithology. Based on a large number of core experimental analysis and detailed log data analysis, major lithological types and distribution laws in Nantun Formation and the strata below the Formation are summed up.What?s more, the variation of log response correspondent with major lithology is analyzed in details. The result of log response analysis provides basis for complex lithology identification in the basin.

Of this century, basin modeling has stepped into a hard time of its development. The famous overseas commercial software corporations have still been working hard and have made some progresses in different aspects. Furthermore, some new comers in this field have joined in. From 1990s to the beginning of the century, basin modeling in China remained international level on the whole, so we have a good base for development. As a long-term research problem, 3-D hydrocarbon migration and accumulation modeling facesmany difficulties and challenges, such as accurate algorithmfor simulation equation, considering and quantitatively processing fault and other geological factors, the reconstruction of intermittent mutation processes of hydrocarbons, and the rebuilding of paleo-hydrodynamic process etc. So the main trend for future basin modeling development will be: to enhance the application of 3- D geological attribute modeling and 3-D structural modeling, to implement interactive modeling for each critical stage under the guidance of hydrocarbon migration and accumulation rules in line with geological laws.

During the rolling exploration in the Huanxiling Oilfield, on the basis of the formation mechanism and fine description of the low-resistivity reservoir, by integrating geology, logging, and core information, and fully using information of oil wells, testing and oil extraction is conducted by selecting suspicious layers of typical wells. Favorable development results are obtained, and the breakthrough of òfinding oil in the wateró in lowresistivity reservoir is fulfilled. Substantial oil and gas reserves are discovered as well. All this accumulates substantial valuable experience for the identification of low resistivity reservoirs.

Simulated annealing of multi-parameter optimization is the simulated annealing wave impedance inversion with some constraints, including S/N ratio, adjacent-channel correlation, deviation of initial model, and threshold value of reflection coefficient. The method can avoid the objective function value into a local extremum and has global optimum solutions. The principles of this method are introduced in this paper. The procedures are high-resolution processing, synthetic seismogram and horizon calibration, wavelet extraction, initial model establishment, simulated annealing inversion, and adjustment of multi-parameter restraints. The actual data processing indicates that: 1) compared to conventional wave impedance inversion, the method can improve the resolution of seismic data inversion; 2) the fault position in coherent slices of original data and coherent slices of wave impedance are coincide with that in structure maps, but the latter can provide a better criteria for fault interpretation than the former.

In Jilin Oilfield, with the development of exploration technology, the old channel evolves into the preferred target for lithologic exploration because of its characteristics like good physical properties and high productivity. But channel identification is still difficult in seismic interpretation because of the limitation of seismic data quality. In view of the actual geological condition of the fourth member of Quantougou Group in Changchunling Region, based on seismic attribute analysis, frequency scanning, characteristics inversion, seismic facies analysis, and visualization sculpture, the methods for old channel identification are carefully selected. The working flow of the method applicable to oil channel identification in Jilin Oilfield is figured out, offering technical support for the development of capacity-building and deployment of exploration wells.

Because of natural weathering, inadequate storage conditions, required routine observation and sampling, how to avoid core loss and its custody has become a more serious problem. To solve the problem, the construction of digital core library is carried out in the Huabei Oilfield. Now a comprehensive core digital network system has been completed. The system can not only reduce repetitive damage to core, more importantly, it is more convenient for researchers to analyze graphic core information, which can help improve exploration and development as well as decision-making.

Kazakhstan is located in the north of CentralAsia, belonging to the southern margin of Laurasia, i.e., the southern margin of Craton and Kazakhstan plates in East Europe. Late Paleozoic continental margin basins, such as the Pre-Caspian Basin, are formed in the region. The closure of Paleo-Tethys results in the continental collision between Tulan Platform (the Amu Darya---Middle Caspian Sea) and Laurasia, followed by the formation of a series ofMesozoic rift basins. There are 11 large sedimentary basins in Kazakhstan, commercial oil and gas has now been discovered in five, that is, the Pre-Caspian Basin, the Mangishlak Basin, the North Usturt Basin, the South Turgai Basin, and the Chu-Sarysui Basin. Kazakhstan is one of the richest oil and gas countries in Central Asia and even in the whole world, of which the recoverable oil and gas reserves reach 55 × 108tand 3 × 1012m3. The country also has great exploration potential, especially in the Pre-Caspian Basin where the recoverable oil resources to be discovered is up to 60 × 108t.