Abstract:Based on the research of the development of boundary faults and their controls of hydrocaronon accumulation in the shallow sea of the eastern part of Jiyang Depression，the tectonic zone of buried hill draped structural belts was divided into three types：single fault-low uplift，double faults-middle uplift and multiple faults-high uplift. The reservoir-seal assemblages in the single fault-low uplift of the buried hill draped structural belts are the best，and good assemblages can occur in each layer. There are different trap types such as lithology trap，structural trap，stratigraphic trap and composite trap.The lithology traps and stratigraphic overlapping traps developed in the lower of the third member of Shahejie Formation and the lower of Dongying Formation in the double faults-middle uplift of the buried hill draped structural belts，and the drape trap and the lithology-structural trap developed in the middle and upper of Dongying Formation. The stratigraphic overlapping traps mainly developed in the multiple faults-high uplift of the buried hill draped structural belts，and the reservoir-seal assemblages generally have poor condition for hydrocarbon accumulation. The next exploration targets are Es3 stratigraphic oil reservoir in Kendong Uplift，Ed lithology oil reservoir in Changdi Uplift and Chengdao Uplift.

Abstract:Combined with the latest research progress of gravity flow deposition theory at home and abroad，the sedimentary characteristics，formation mechanism and sedimentary models of the gravity flow sand bodies in the Sha3 member of the slope zone in the southern part of the Bonan Sag in Zhanhua Depression were studied systematically using core data，granular analysis，well logging and other information. The research shows that the gravity flow sand bodies mainly include sliding-slump sand bodies，sandy debris flow sand bodies and turbidite sand bodies based on the rheological characteristics and sediment support mechanism in the study area. The sliding-slump sand bodies distribute dispersedly with abundant synsedimentary deformation structures；the sandy debris flow sand bodies are thick and massive with floating mud gravel inside；the turbidite sand bodies area mainly composed of thin layer sand and mudstone with the coarsening upward succession. The sliding-slumping sand bodies are mainly distributed at the upper part of the slope zone；the channel microfacies dominated by sandy debris flow sand bodies and the channel edge microfacies dominated by turbidite sand bodies develop at the middle and lower part of the slope zone，which presents a belt-like distribution. The channel end microfacies dominated by sandy debris flow sand bodies and the interchannel and the sheet sands microfacies dominated by turbidity sand bodies distribute in the sag zone，which presents a fan-like distribution. According to the distribution law and formation mechanism of gravity flow sand bodies in the study area，the sedimentary model of gravity flow sand bodies in the slope zone of rifted lacustrine basin was established under a multi-source，mud-rich and sand-less condition.

Abstract:It is of scientific important to understand the spatial and temporal order of Cenozoic structure deformation in the Western Qaidam Basin，which can improve the study on the uplifting process of the Tibet Plateau，and it also provides a new method of“exploring oil based on structure”. In this paper，the latest seismic data，borehole data and core data acquired from the Western Qaidam Basin in the last few years were used to study the spatial and temporal order of structure deformation in the Cenozoic based on the growth strata analyzing method. Study results indicate that：①the overall structure deformation in the Cenozoic of the Western Qaidam Basin is getting younger from SW to NE；②the distribution of the tectonic deformation in the Cenozoic of the Western Qaidam Basin is stratified in the time domain and spatial domain，which was resulted from the progressive transformation of the structure displacement along the detachment surface；③the western part of Yingxiongling structure belt and the Kunbei and Wunan areas are the most favorable exploration areas. The eastern part of Alar and Yingxiongling structure belt and the northern part of the Western Qaidam Basin are the secondchoice，while the areas from Eboshan to Huanggualiang are risky.

Abstract:There are potential for tight oil in the Shahejie Formation in Bohai Sea area. Geological characteristics and forming conditions of tight oil were researched in the Shahejie Formation in northeastern subsag of Laizhou Bay Sag，which is based on the well drilling，well logging，geological log and seismic data and combined with the core observation，thin section analysis and a lot of laboratory analysis data about geochemical and reservoir physical property. The research results show that there are geological conditions for tight oil in northeastern subsag of Laizhou Bay Sag，where oil and gas mainly accumulate in the widespread effective reservoirs that are interbedded or contacted with high-quality hydrocarbon source rocks. Dark gray mudstone，deposited in semi-deep and deep lacustrine facies withⅡ1 type kerogen，distributes widely in the third member of Shahejie Formation，which provides sufficient oil source supply for tight oil formation. Large-scale rapidly deposited delta sand bodies in the Shahejie Formation provide storage space for tight oil accumulation. Alternativelydeposited layers of high-quality hydrocarbon source rocks and large thick good reservoir result in a good relationship between source and reservoir，which provides benefit configuration conditions for near-source hydrocarbon accumulation. Abnormal pressure provides driving force for charging during the hydrocarbon accumulation period for tight oil formation.

Abstract:Middle-shallow crude oil is mature and light with the characteristics of low-density，low-viscosity，low-chill point，waxy，low-sulfur and colloid in No.2 Structural Belt of the Nanpu Sag，which is not biodegraded basically. Based on the geochemical characteristics of source rocks and crude oil，the source rocks are divided into Type I and TypeⅡ，which are respectively distributed in Es3+2 and Ed. The Type I source rock is better than the TypeⅡ. The crude oil can be divided into Type A，Type B and Type C. Type A oil has lower gammacerane content，while Type B oil has higher gammacerane content. The regular sterane C27，C28，C29 of the three types of crude oil are characterized by the typical features of“√”，“L”and “V”. The kerogens are from both lower hydrobiont and higher plants，which are formed in lacustrine environment characterized by weakly oxic to weakly reducing fresh water. Type A and Type B crude oil are respectively related to Type I and Type Ⅱsource rocks，and Type C of crude oil is from both Type I and TypeⅡsource rocks. On this basis，the source of different crude oil could be determined，and according to the relation of the source and the reservoir，the model of oil and gas migration and accumulation in middle-shallow reservoirs was established. The faults act as paths for upward migration of deep oil and gas. The crude oil types and petroliferous property in both side of the faults are controlled by fault sealing. Abnormal high pressure in deep stratigraphy provides driving force for the migration of deep oil and gas. The relationship between source rocks and faults influences the distribution and type of the middle-shallow crude oil.

Abstract:Many underwater distributary channels develop generally at the braided river delta front，which also controls the distribution of other microfacies，so it is important for well pattern deployment and oilfield management to determine the distribution and superposition of underwater distributary channels. The braided river delta front develops in the Shahejie Formation in the east of JX Oilfield. The channel sands overlay each other vertically and connect each other laterally because of swinging of underwater distributary channels. If the channel sands are in the same underwater distributary channel，they connect well with each other. If not，they are poorly connected. The pressure of oil well is low in the oilfield at present，but the injection well presents the appearance of overflowing，which seriously affects the development effect and reduces the recovery ratio. The distribution patterns of channel sands in underwater distributary channel that parallel with the provenance are determined through analyzing depositional marks，deposition characteristics and sand description by application of well and seismic combination，and they become thinner and change into mudstone finally. Channel sands in underwater distributary channel that perpendicular to the provenance deposit in parallel or overlay each other. Their thickness is characterized by thick-thin-thick and their lithology is characterized by sand-clay-sand. The results verified by dynamic materials are accurate and reliable. The development measures in the research area are adjusted based on distribution patterns of reservoirs，and finally has gotten much better results.

Abstract:Low amplitude structure developed in Jurassic Yanan Formation in the southern section of Tianhuan Depression.Due to the influence of complex tectonic evolution of the conterminous southwest margin，it is difficult to reveal the regularity of hydrocarbon accumulation in the low amplitude structure. So exploration deployment is difficult. In order to improve the prediction effect of low amplitude structure of the Yanan Formation in the southern Tianhuan Depression that is covered by 2D seismic data，tomographic static correction technology was optimized to solve the problems of long and short wavelength imaging，and therefore the precision of low amplitude structure mapping can be improved. After that，reverse linear noise suppression technique based on data reconstruction was used to reprocess the data which have problems of strong interference and low signal-to-noise ratio in loess tableland area. On the basis of fine processing，by using subtle velocity field，variable-velocity and small grid of large-scale mapping，the“fasle-high”caused by high-speed conglomerate-interlayer was removed and the structure can be mapped correctly. Finally，the trend surface analysis was utilized to highlight the local structure heights. Nineteen low amplitude structures were determined based on comprehensive use of the integration of data process and interpretation mentioned above. It has been proved by drilling that the low amplitude structure prediction technique has a good effect on low amplitude structure prediction in area that is covered by 2D seismic data.

Abstract:The Late Permian coal-accumulating area in northwestern Guizhou is an important coal-forming area in south China. So it is necessary to strengthen the geological research and to clear sequence stratigraphic framework as soon as possible. Compared with the traditional methods of using the core and logging data to divide the sequence with many subjective human factors，the wavelet transform technique has advantages of dividing sequence stratigraphy quantitatively. The relationships of sequence structure in northwestern Guizhou with time frequency energy spectrum and wavelet curve were analyzed to build up the wavelet transform models of transgressive system tract and highstand system tract of the study area.The energy clusters in the transgressive system tract gradually increased from deep to shallow，and moved from small scale to large scale；the energy clusters in the highstand system tract gradually decreased from deep to shallow，and moved from large scale to small scale. The third-order sequence was divided according to the sequence interface recognition results，the features of wavelet curves and the variation of time-frequency energy spectrum. Finally，the coal measure strata of Longtan Formation in the study area were divided into 4 third-order sequences and 8 system tracts，and each sequence was composed of transgressive system tract and highstand system tract while the development of lowstand system tract was not obvious. The division results show that the sequence boundaries defined by wavelet transform are consistent with those defined by the traditional methods.

Abstract:Coalbed methane content is an important indicator of CBM resources assessment，development deployment and economic evaluation. By analyzing a large number of experiments，the main controlling factors of the coalbed methane content in Block XX of Kgalahari Basin were studied. The studies show that the vitrinite in organic macerals of coal experienced the gelation function and the inertinite experienced the silk-coalification function. The coal rich in vitrinite has higher methane content and stronger adsorption ability，while the coal rich in inertinite has lower methane content and weaker adsorption capacity. Coal rank controls the production of coal-bed methane and the development of coal reservoir pore and cleat. When the vitrinite reflectance（Ro）is less than 0.5%，a small amount of biogenic gas is generated and the primary pore is well developed in coal. The adsorption ability of coal seam is poor and the content of coalbed methane is low. When the Ro value ranges from 0.5% to 4.0%，the organic matter experiences thermal degradation and thermal cracking，a large quantity of methane was generated. Along with the increasing of the Ro values，the degree of micropores and cleats development in coal increase gradually as well as the specific surface and the gas content. When the Ro value is above 4.0%，the degree of micropores and cleats development in coal decreases as well as the specific surface and the gas content. Coal ash is negative correlated with coalbed methane adsorption capacity. When the coal ash content is less，the adsorption capacity is stronger and the coal bed methane content is higher. Good preservation condition can be achieved when the rock in coal seam roof is dense and low in permeability and the wells are far away from the fault，and thus the coalbed gas content is relatively high.

Abstract:Productivity prediction is of great significance to reservoir development optimization. Based on the geological characteristics of carbonate reservoirs and the development characteristics of fractured vertical wells，a unsteady compound productivity model for the fractured-vuggy carbonate reservoirs was established. The Laplace space solution was obtained by Laplace transform，and the production curve was plotted by stehfest numerical inversion. Cases results show that the accuracy of the model was verified by the comparison of the results calculated by the new model with the actual production data. The change trend of dimensionless production curve shows that the fluid flow can be divided into seven stages：linear flow in artificial fracture，transition flow A，linear flow in natural fracture，bilinear flow in natural fracture and artificial frac ture，transition flow B，matrix linear flow and boundary control flow. The analysis results of influencing factors show that the storage ratio has an effect on early and late stage of productivity. The early stage of productivity is lower when the relative storage ratio between natural fractures and artificial fractures is larger. The larger the relative storage ratio between the matrix and the dissolution pore，the smaller the later productivity. While the medium-term productivity is affected by the channeling coefficient. The higher the channeling coefficient，the lower the drop rate of the medium-term productivity.

Abstract:After physical property change of radial pore medium saturated by single phase fluid was analyzed under low-frequency vibration，influence of low-frequency vibration oil recovery on the actual reservoir flow with various pressure gradients near the wellbore may be known. The control equations for elastic wave propagating were established，which shows the influence of the low-frequency vibration on the initial flow of the radial reservoir. Considering the consistency of directions of elastic wave and initial Darcy flow around the wellbore，physical model meshing was made according to the mapped meshing and boundary mesh refinement to weaken the boundary spurious reflection. By comparing coupled vibration flow with Biot flow and initial radial flow based on finite element simulation of COMSOL system，it is demonstrated that the numerical simulation can reveal the effectiveness of periodic changes of reservoir physical property under the influence of the low-frequency vibration according to the difference in semi-analytical solution. The research results present that the coupled vibration flow is not simply equal to the sum of Biot flow and initial radial flow. The low-frequency vibration has obvious function of increasing the seepage velocity and permeability and decreasing the injection pressure in the radial flow field when the vibration source is in the injection well；the effect is more obvious near the injection well. The local maximum pressure decrease ratio reaches 40%，and the action range with significant velocity increase is 10 m to the center of wellbore. The effect is more obvious at lower permeability and higher porosity.

Abstract:It is generally believed that a long ellipsoid drainage area could be formed during the horizontal wells production，but the actual drainage area is just one part of the ellipsoid for the thin reservoirs that are sealed at the top and bottom.According to the seepage law of thin reservoirs，the three-dimensional flow problem was divided into two parts，including the horizontal plane elliptic flow far from the wellbore zone and the vertical plane radial flow near wellbore. Based on the principle of hydroelectricity similarity，Lame coefficient of the elliptical coordinates was introduced，and the productivity formula of horizontal wells was established for the thin reservoirs. But a complete ellipsoid drainage space could be formed in the thick reservoirs，which could be divided into a pseudo cylinder and two hemispheres. The productivity formula of horizontal wells in the thick reservoirs was established by introducing average short half axis theory and mass conservation principle as well as the equivalent flowing resistance method. Through the comparison and analysis of the deduced formula and the other five classical productivity formulas，the average deviation of the horizontal well productivity calculated by the new formula in the reservoirs of different thicknesses is less than 2%，which shows that the calculation results are reliable.

Abstract:To offer better guidance to the physical simulation experiment scheme and model parameters design of water flooding in low permeability carbonate reservoirs，the similarity theory on the oil-water two-phase seepage simulation was analyzed further. Starting from seepage theory of deformation media，mathematical model of nonlinear flow for dual porosity media was established considering variation regularity of stress sensitivity of permeability and starting pressure gradient.The similarity criteria of physical water flooding simulation in the low permeability carbonate reservoir was deduced by analytic equation method. The dimensionless equation was solved using IMPES method，and the principal and subordinate relations of various similarity criteria were determined quantitatively by distortion and sensitivity analysis，which were verified by the results of stress sensitivity experiment and water flooding experiment. Results show that this model veritably represents the regularity of water flooding in the low permeability carbonate reservoir. Twenty-one similarity criteria have various effects on objective function. When the model and prototype are not completely similar in the physical simulation design，the permeability and saturation of the porous medium and the viscosity and density of multiphase fluids should be given priority，as well as the pore structure similarity.

Abstract:According to the current imperfections in the study of low-permeability reservoir classification，a low-permeability block in Xinjiang was selected as an example. Firstly，the classification parameters were selected. Secondly，combined with the distribution of the actual reservoir classification parameters，preliminary reservoir classification boundary of this block was given. Finally，the reservoir classification parameters were characterized and analyzed comprehensively by the reservoir numerical simulation technique，and the influence degree of each parameter on the productivity was evaluated，which are in the descending order as follows：threshold pressure gradient，permeability，pressure sensitivity factor，effective porosity，oil viscosity，movable fluid percentage，mainstream throat radius and clay mineral content in ascending. By assigning weights to each parameter according to the influence intensity，the reservoir comprehensive classification coefficient was constructed，an eight-element comprehensive classification method was proposed. This method was applied to draw the scatter diagram of actual single-well production distribution in the target block. It is found that the reservoir comprehensive classification coefficient is consistent with the single well production of the block，and the accuracy of the method has been proved. Finally，according to the on-site classification criteria for the target block based on oil production capacity，the reservoirs were divided into 4 types based on the level of productivity using this method.

Abstract:The two-dimensional，two-phase seepage problem in dual-porosity medium is hard to derive its analytical solution when the imbibition effect of fracture-matrix was considered. By introducing the concept of travel of time（TOF），the two-dimensional，two-phase problem is simplified into a one-dimensional，two-phase problem. Along the streamline，the characteristics method can be used to solve the analytical solution of dual-porosity medium. Taking the five-spot well pattern for example，the effect of imbibition of fracture-matrix on the water flooding development in the dual-porosity medium was analyzed，and the calculation methods of saturation distribution for homogeneous and heterogeneous reservoirs were given respectively. Research results shows that the advance speed of water flooding front in the dual-porosity medium is fast，and the water breakthrough quickly occurs in production well in the dual-porosity medium. However，the water cut increas? es slowly after water breakthrough because of the existence of imbibition effect. The crude oil in the matrix system is recovered by the imbibition effect of fracture-matrix，therefore，water flooding is an effective method to develop fracture-pore carbonate reservoirs. The research results provide an effective analytical model for the research on the development characteristics of water flooding in the dual-porosity medium.

Abstract:The ultra-deep gas reservoir in the Keshen Gasfield is characterized by complicated geological conditions，poor seismic data and great difficulty on gas reservoir description，making it a world-class challenge of exploration and development. To understand the characteristics of gas reservoir deeply，long distance multi-well and multi-azimuth interference well-testing was carried out in many gas reservoirs of Keshen Gasfield. Accurate multi-well interference data were acquired and verified by both positive and negative authentication. Approaches like extremal value analysis，investigation radius method and so on were employed to analyze the tested data，which was also compared with numerical simulation results based on the geologic study of the gas reservoirs. The results of investigation show that the interference signals in the developed area of Keshen2 gas reservoir are strong，indicating that the reservoir is highly connected with the well-developed natural fractures. Few faults or dominant fractures appear. The fracture permeability is above Darcy level. Obvious interference signals were detected between Keshen5 and Keshen11 gas reservoirs，which means that the two gas reservoirs are interconnected and proved to be the same one. Results from numerical simulation show that the connectivity in the west area is better than that in the east. This technology has realized quantitative analysis of fractured gas reservoir in Keshen Gasfield，which is of great significance for the effective exploration and development of ultra-depth，high-pressure and fractured tight sandstone gas reservoirs.

Abstract:Rock resistivity parameters are important data for reservoir oil saturation evaluation and reserve calculation by logging data. Laboratory core testing is the only way to obtain rock resistivity parameters. Influencing factors on the test results of rock resistivity parameters for the low permeability sandstone reservoir in Shengli Oilfield were analyzed from two aspects of experimental methods and experimental conditions. By means of factor comparison experiment，the influence of displacement method，displacing fluid，temperature，confining pressure and brine salinity on cementation exponent m，saturation exponent n and lithology factor a and b was discussed. The research results show that quasi-static displacement process of semipermeable plate method is similar to the oil accumulation of the oil reservoir whatever the displacement media is. The rock resistivity parameters is not sensitive to the experiment temperature，but is influenced by confining pressure and formation water salinity greatly. At last，technique of laboratory measurement of rock resistivity parameters for the low permeability sandstone reservoir was determined. Experimental water was prepared using the formation water with the same salinity，the semipermeable plate method was applied for water drive by gas or by oil，effective overburden pressure was simulated on the condition of indoor temperature，and the rock resistivity parameters of the low permeability sandstone reservoir were tested.

Abstract:The influence of gas injection cycle，production pressure and permeability on the huff and puff effect of tight oil reservoir in the Lucaogou Formation of Jimsar Sag of Junggar Basin were analyzed through the physical simulation experiment of N2 huff and puff of the cores. The results show that cycle recovery rate decreases and the huff and puff effect becomes worse with the increase of huff and puff cycle；after 5 cycles，the cumulative recovery rate is increased by 6.81%-13.88%，which was about 2.5-3 times of that of elastic depletion，but the oil recovery is increased mainly in the first three cycles. Low production pressure and high permeability can bring larger cycle recovery rate and higher utilization of injected gas，and thus the effect of huff and puff is better. According to the experiment results，it is considered that there is feasibili? ty of N2 huff and puff in the study area. When the reservoir permeability is low，it is necessary to take measures such as fracturing and acidification to improve the reservoir permeability and the huff and puff effect，but the huff and puff should not exceed three cycles.

Abstract:Low permeability reservoir has poor physical properties and small pore throat，so it has great seepage resistance in the process of water flooding. It is difficult to establish an effective displacement pressure gradient between injection wells and production wells. It is very important to establish a description method about seepage resistance and study the influencing factors and feature of seepage resistance change of water flooding in low permeability reservoirs. A mathematical model of seepage resistance gradient of the water flooding in the low permeability reservoir was established based on the law of conservation of mass flow of oil and water. The variation feature of the seepage resistance gradient was analyzed by the function of the change rate of seepage resistance gradient，which provides a macroscopic characterization method of seepage resistance gradient of water flooding in low permeability reservoir. Theoretical analysis shows that the seepage resistance gradient shows nonlinear feature in the process of water flooding in low permeability reservoir，which increases first and then decreases with the increase of water saturation. There is a maximum seepage resistance gradient in water flooding of low permeability reservoir，which is related to water injection rate，fluid viscosity and reservoir permeability.The higher the water injection rate，the larger the maximum seepage resistance needs to be conquered；the higher the oil viscosity，the larger the maximum seepage resistance needs to be conquered；the lower the reservoir permeability，the larger the maximum seepage resistance needs to be conquered.

Abstract:In order to improve the recovery of the reservoirs with strict conditions，new type of chemical agent was selected，and the effect of hydrophobically associating polymer on the dynamic interfacial tensions of straight and branched chain betaine solutions against kerosene have been studied. The influence of oleic acid in the oil on interfacial tension of betaine systems were investigated. The experiment results show that for both kerosene and model oil containing oleic acid，the mixed adsorption of hydrophobic part of hydrophobic associated polymer and straight chain betaine ASB will lead to the reduction of interfacial tension because the large spaces exist between hydrophobic chains of ASB，which comes from the large size of hydrophilic part in betaine molecule. The compact film will be formed by branched chain betaine BSB because the size of hydrophobic part matches its hydrophilic part. Therefore，the adsorption of hydrophobic part of associated polymer will destroy the tight arrangement of BSB film and result in the obvious increase of the interfacial tension values.