The 3rd and 4th members of Jialingjiang Formation (J3-4) concentrate in the periphery and extended part of the core of Luzhou palaeohigh, while no gas reservoir has been discovered in the core of the palaeohigh. The main cause is that there are no gas generating conditions in the core. At the gas source zone, there are no faults in the gas source zone that are connected with the J3-4 reservoir. Denuded by the Indochina movement, the core of the palaeohigh has no cap rocks like the J4 gyprock. Research shows that the palaeokarst gaps and bores are the basis of J3-4. After evolution for several times, the J3-4 reservoir is combined into the reservoir with complicated palaeostructures, and it is not limited by structures any more. Even though there are palaeokarst gaps and cracks in the syncline, the J3-4 reservoir has broad exploration prospect. Therefore, further exploration will focus on the periphery, the extended parts in the west and east of the core of the palaeohigh.

Oil and gas exploration wells concentrate in the rifted basins with high hydrocarbon enrichment and large area in east China. They are mainly distributed in the medium-deep strata of Paleogene, and nonstructural traps take the dominant. It is concluded that the exploration failure is caused by hydrocarbon sources, reservoirs, traps and their preservation, engineering, and etc.. Research on exploration failure in the past three years shows that the main cause is the traps and their preservation, reservoirs take the second place. To realize the exploration targets in complicated lithologic traps, lowamplitude structures, complex small faulted blocks and deep structural traps, high-resolution seismic acquisition techniques with high signal-to-noise ratio and reservoir predicting techniques need to be improved.

This paper discusses the buried-hill development in northeastern Jiyang Depression from the perspective of tectonic movement. It is pointed out that the buried-hill development in the area has experienced tectonic movement for several times, such as the Indochina movement, the Yanshanmovement, and the Himalayan movement. According to the effect of fault movement on buried-hill development and the structural location of buried hills, the buried hills in the area are classified into five types, i.e., the gentle-slope block fault buried hill, the steep-slope detachment buried hill, the monadnock buried hill, the buried hill shapes like a hill over the slope, and the strike slip nappe buried hill. Horizontally, the buried hill in the area has the laws as follows: Hydrocarbon enrichment of the lower uplift is higher than that of the uplift, but it is lower than that of the buried hill. It is the highest in the buried hill next to the boundary of oil sags and faults.

Many late Jurassic to early Cretaceous rifted basins developed in deep Songliao Basin. The hydrocarbon enrichment degree of the basins varies a lot from each other. According to the research of more than 50 rifted basins, it is found that the different geological conditions result in the difference. The geological conditions include: the location of fault depressions in the basin, the difference in the structure of fault depressions, the activity intensity and periods of the controlling fractures, and the volcanism. Among them, the location of fault depressions in the basin and the difference in the structure are the most important. These rules can be important reference to the evaluation of the strategic area selection of peripheral fault depressions in deep Songliao Basin.

The single fault depression of Dongpu Basin evolves into median fold with two low-lying lands and slope because of the structural movement, and the generated different rift systems interlace and cut mutually. North-East (NE) tensional rift systems with echelon, gradual change, partition characteristics mainly developed in the area. The system is with the rule that it coexists with positive structures and it grows at the sand body's brim, also its generation is related with regional tenso shear function, structural event style, lithologic factor, interconversion of the stress condition, structural setting and boundary condition, so the structures and hydrocarbon accumulation get more complicated and the exploration for oil and gas becomes more difficult in the area.

2D stimulated experiment on oil migration and accumulation in interlayer heterogeneous sands is carried out by taking different filling ways. It is shown that the routes of oil and gas migration and oil zones vary a lot from upward sands with different heterogeneity, i.e., different permeability contrast, under different filling ways and energy conditions.When the permeability contrast is small, the sands with medium permeability in the middle tend to become the oil layers and the routes for oil and gas migration, as compared with the sands with high permeability in the lower part and the sands with low permeability in the upper part. When the permeability contrast is big, the sands with high permeability in the lower part will become the oil layers and the routes for oil and gas migration, as compared with the sands with medium permeability in the middle and the sands with low permeability in the upper part. Under steady conditions, oil zones are the same by the ways of lateral filling and fault filling, the oil saturation features in "rhythm" vertically. Under fault episode filling conditions, oil area gets larger, sands with medium and high permeability become oil beds, and the migration efficiency in high-permeability sands gets higher.

Based on conducting marine carbonated reservoir research on one exploration area in the Sichuan Basin, according to the characteristics of field seismic data, the factors resulting in amplitude distortion are analyzed. Combined with the OMEGA SPS (seismic processing system), research and development of key pre-stack image processing technologies with true amplitude are emphasized for application. Refraction tomographic static correction is applied to iterative correction of near surface models, aiming at reducing the difference between the travel time calculated and the first-arrival picking value and developing near surface models with high accuracy. So the problem of static correction caused by horizontal change of near surface velocity is solved. Non-surface consistent residual statics is applied to solve the problem of residual high-frequency statics caused by the outcrop of high-velocity layers. Nonlinear abnormal noise attenuation of separate frequency and time variation is applied to eliminate the noise with abnormal amplitude and frequency of shots,meanwhile, the relative amplitudes among effective signals will be not been changed. False pre-stack time image caused by heterogeneous offset distribution is wiped out based on the application of regularization technologies, so common imaging gathers and angle gathers with true amplitude are obtained. Through pre-stack amplitude-preserved processing, the relative amplitudes among pre-stack common imaging gathers are kept well in the studied area, the signal-to-noise ratio and resolution are improved greatly. Therefore, the amplitude near the target layers of calculated angle gathers feature in obvious variation. Pre-stack inversion and fine interpretation in marine carbonate gas reservoirs are fulfilled successfully.

As the oil and gas exploration goes further, more and more oil and gas resources are discovered. How much oil and gas remain to be discovered in mature oilfields is an important question for petroleum geologists. The paper presents the exploration benefit approach to assess remaining oil potential in the Jinhu Sag, North Jiangsu Basin, and briefly discusses the principles and steps of the exploration benefit method in oil and gas resources assessment. Research shows that the oil and gas reserve undiscovered in the Jinhu sag is about 3320~36701 ×04t. Practice proves that the exploration benefit method slides over the problem of oil and gas genetic mechanism in reason and reduces the subjective impact on oil and gas resources evaluation effectively, which makes the results of oil and gas resources evaluation more objective. So the method will have broad prospect for application

According to the exploration in Changyangdian buried-hill of Raoyang sag, systematic ideas aiming at buried-hill exploration are developed preliminarily. Firstly, the comprehensive geological characteristics and complicated relationship between oil and water are analyzed, and exploration targets are determined. Then high-precision 3D seismic acquisition techniques and pre-stack migration processing techniques are fully utilized, and the quality of seismic data is improved. At last, accurate seismic data interpretation is made and accurate trapping is fulfilled. Based on the comprehensive evaluation on oil sources, reservoirs, and sealing conditions, a new accumulation model-new source, paleo sealing and reservoir formation- is developed. Finally a new buried-hill trap, i.e., the Chang 3 well buried hill is fulfilled. Plenty of oil and gas stream is obtained in Wumishan Formation.

The data of geology, well logging, core analysis and capillary pressure test are comprehensively used for analyzing the characteristics of Chang2 low resistivity zones in Jiyuan area. The calculation model of Reservoir parameters is established with the features of low resistivity zone.Water content ratio is used for quantitative evaluation on the low resistivity hydrocarbon reservoirs. Practical production data from 23 wells proved the above methods and standards are feasible, by which the method is proven for easy and effective application.

In this paper, the essential ideas and condition factors on economical value of onshore natural gas fields in China are analyzed preliminarily, and then the interrelated geological factors are discussed. Conclusions are deduced as follows. Firstly, the depth of reservoir and the sand parameters of natural gas fields have direct correlation with development investment. Secondly, geographical elements and corresponding material parameters of natural gas deposits exert greater effect on production cost. Thirdly, reservoir abundance, efficiency thickness, reservoir porosity, permeability, and types of onshore natural gas field have greater impact on gas production. On the basis of production per km-well per day, the economic production factor-weighed and computing formula of onshore natural gas fields in different capital, cost and price is approached, then the economic estimation criteria in different onshore natural gas fields are formulated, and some examples of typical onshore natural gas fields in China are analyzed, including the Sebei-1 gas field, the Changqing gas field, the Kela-2 gas field, the Hetianhe gas field, the Wubaiti gas field, the Wen-23 gas field and the Qianmiqiao gas field.

The information construction has entered into a new stage, the 'departments barriers' and the 'information isolated island' have been eliminated. Information integration is realized. At present, the information systems of exploration and development are incompatible, the information construction of operation andmanagement is weak. It does not correspond with themanagement system featuring in the integration between exploration and development and the operating system focusing on project management. To enable information construction to serve intensive exploration management and become the strategic resources of exploration, we should eliminate the idea which emphasizes too much on networks and information technology, but neglecting data and information management technology, focusing on the establishment of information integrated system, beginning from the overall program of strengthening leadership, changing concepts, and doing well in exploration information construction, carrying out resources integration of exploration information of different departments.

In Kolzhan area, land sources, carbonate rock and mud shale of Devonian and Lower Carboniferous are the main source rock, and they feature in thick source rock, high abundance of organic matter and favorable hydrocarbon conditions. Carbonate rocks with strong heterogeneity are major reservoirs. In addition, two sets of source-reservoir-cap assemblages combinations of self-storage reservoir and below generation-up reservoir developed. Kungurian salt of Permian is of the vast majority of the high-quality regional cover in the basin, of which traps are dominated by structural and stratigraphic traps and reservoirs are mainly distributed in subsalt anticline structure. Through the analysis of the forming conditions of the basin, with well K drilling in Kolzhan area, it is shown the subsalt hydrocarbon accumulation is dominated by the structural traps and reservoirs in the area, and to find effective traps is the direction of exploration for oil and gas in the area in the future.

Image basins and hydrocarbon fluids are developed during the evolution of the earth under sphere movement and gravitational differentiation. Hydrocarbon fluid exists in the mantle fluid in the spheres of the earth and it is a kind of supercritical heat generating and transporting fluid with high compression, high density and high energy. It is composed of organic compounds with extremely strong reducing property, and the components are H, H2, CH4, and CO. The earth has four high pressure gas-spheres al least, such as the gas-sphere in the outer core, the gas-sphere in the upper mantle, the gas-sphere in the middle crust, and the gas-sphere in the upper crust, The hydrocarbon fluid in the gas-sphere features in high energy, high pressure, high temperature, strong chemical activity, and high penetrating capacity. Lower image basins are the best choice for storing hydrocarbon sources. To find low-velocity bodies in upper image basins where deep large faults developed and correspond with each other is the basis for discovering large oil and gas fields