The regions of Hunan and Guangxi，which were in the composite position intersected by a variety of Tectonic system in Devonian，and developed a unique“platform- depression-dome-basin”sedimentary system. Formation of Devonian were eroded badly in Hunan and Guangxi Provinces，which merely remained in Nanpanjiang depression，Qianxinan depression，middle and west of the Guizhong depression，Shiwanshan Basin and Xiangzhong depression. Researching on various sedimentary facies symbol in residual formation，9 types of sedimentary facies were recognized，which dominated in the marine environment. The followed conclusions were obtained from the difference comparison of sedimentary environment：Nanpanjiang depression and Guizhong depression are mainly of depression-platform sedimentary system；Xiangzhong depression is mainly of clastic tidal flat and restricted（open）platform sedimentary system，and Shiwanshan basin is mainly of undercompensation basin. Sedimentary mode of study area was displays the feature“depression surrounded platform，depression connected”. Facies differential degree of sedimentary evolution，the tectonic movement and magmatic activity have good sedimentary response relation.
Strata found in Well Le2X in Hepu Basin are mainly off-white，variegated and purple-red，and dark mudstone is thinner than others，only Jiuxikeng group of the Pliocene is thicker，but its bury is not deep，and belongs to prematurity stage. The Chuanjiang fault block structural trap of Well Le2X is basically clear，but the traps is without basic hydrocarbon source conditions and is away from the hydrocarbon source supply system，resulting in the fault block traps becoming empty traps， which is the main reason for the failure drilling. Therefore，in-depth analysis of the low mature source rocks and hydrocarbon source supply system，comprehensive prediction and delineation of favorable migration and accumulation of enriched zone of low mature oil and gas and bio-gas within effective hydrocarbon source supply system，should be the key to oil and gas exploration research in Hepu Basin.
The I Oil Group in Member 2 of Zhujiang Formation in A Oilfield is the main reservoir. It’s production status shows that the type，sealing ability and spatial distribution of the interlayer severely affect the reservoir development effect. Through analyzing the core observation，thin section identification and physical analysis，we consider there widely exist calcareous， argillaceous and physical inter-layers. The calcareous interlayer most seriously affects the development. Because of the few well numbers，sparse well network density and limited coring，we cannot study the spatial distribution of interlayer of the whole district only by distinguishing intercalations from the core and logging. On the basis of finely dividing and correlating layers，sedimentary microfacies，the research makes full use of horizontal section information，combines well and seismic， unites geophysical information and successfully predicts the three-dimensional spatial distribution of interlayer by analyzing the model，which is established due to the innovative application of seismic cooperative sequential Gauss simulation on sedimentary facies tract conditions. The predicted results are agreed with the dynamic production，it provides a strong basis for oilfield production and measures for tapping potential of remaining oil.
Leikoupo Formation has a large amount of resources，but in addition to the previously found Wolonghe，Moxi gas reservoir，no other reserve of scale has been found. With the progress of exploration of the marine strata in western Sichuan，especially further degree of exploration，the T2l1 1 gradually exhibits its good exploration prospects. Based on Leikoupo Formation determination，and according the field profile，debris samples，oil drilling and test data analysis，we think that the sub-section of the T2l1 1 belongs to the reservoir controlled by shale facies which is similar or equivalent to Moxi and Wolonghe reservoirs. Structural traps and fault development in the area are conducive to oil and gas migration and accumulation. Comprehensive analysis reveals that the most favorable exploration zones are the Zhongba—Shuangyushi belt in the front north of Longmen mountain and the Meishupu—Jiulongshan belt in the front of Micangshan mountain.
By using of core and close spacing log information，the lithologic features and log response features of the calcareous intercalation in delta front reservoir of Shengtuo Oilfield were proposed systematically. on that basis，we recognize the distribution pattern of calcareous intercalation in high-resolution sequence stratigraphic framework based on the accurate strata correlation. The biogenesis mechanism was presented to improve the genetic model of calcareous intercalation. The study shows that the distribution of calcareous intercalations has selectivity，which is always in the top of sandbody formed in short-term downward base level cycle. The extension scale of calcareous intercalation in strata profile is not big，and always transits to be muddy or silty depositional interface，which shows the calcareous intercalation as an approved sequence interface or subdivision interface of composite sandbody in the delta front reservoir. The areal distribution of the calcareous intercalation is correlated with the depositional microfacies，which is selectively located in the regional debouch bar near the subaqueous distributary channel in a single depositional unit，and presented as separate lump shape. The intensive tulotomoides terrassa are found in the calcareous intercalation，and the subsistence and aggregation patterns of tulotomoides terrassa coincided with the selective distribution pattern of calcareous intercalation，which indicates the biogenesis mechanism.
The low-resistivity annulus is the strong evidence of available oil and gas，and the effective means of judgement of oil and gas layer，especially the low resistivity oil and gas layer. Based on the flow equations of oil and water two phases，the seepage driving velocity is derived during mud filtrate invaded formation，and the process of forming low-resistivity annulus was analyzed. The high frequency induction log can get five resistivity curves at one time. From the reaction of the curves，we can see there are three manifestations for low-resistivity annulus and they are R07 the lowest，R10 the lowest，R11 the lowest， respectively. The paper analyzed the formation process of low-resistivity annulus and reservoir characteristics through the three manifestations. Some examples of the three manifestations of low-resistivity annulus and the process result from high frequency induction log were presented，the results shows that we can quickly tell the reservoir is oil layer，water layer or oil-water layer.
In order to solve the partitioning problem on the bottom boundary of lower Silurian Longmaxi Formation，based on previous researches，with the macroscopic and microscopic observation of outcrops and drilling cores and the analysis of well logging，mineralogical and geochemical data in Sichuan Basin and its peripheral areas，the differences between Longmaxi and Wufeng Formation show that there are higher limy content，many brachiopods，low GR and high RT logging values，high calcite content and lower TOC values in the top of Wufeng Formation，while the bottom of Longmaxi Formation have none limy content，none brachiopods and abundant graptolites，high GR and low RT logging values，high clay and quartz content， highest TOC values. The study suggested that the detection of limy content and comparison of log are the fast and accurate methods of demarcating Longmaxi Formation bottom boundary in practical operation，and it can provide some theoretical basis for furthermore shale gas exploration in Longmaxi Formation of Sichuan Basin.
The massive fine-grained sandstone developed from the thick mudstone lager powder of late Miocene deposits in shallow yellow stream group in Yingge Sea Basin is the recent gas exploration hotspot. The reservoir is sand vertically stacked multi-stage，and changes fast horizontally. Though tectonic evolution and ancient deposition setting control the distribution and evolution of third-order sequences framework within Huangliu Formation，they do not control the distribution of depositional systems or reservoir sand bodies. Compared with the classic submarine fan phase，typical deposition characteristics can hardly be found in this depositional system like obvious fan body sub-phase differentiation，main waterway，levee，etc. It is considered as a channel sand bodies’ combination of small-scale，fast migration，and thick accumulation. In the article，it is called non-typical Turbidity current，using different channels + spring current to show this sedimentary characteristic. The studies suggest that the unstable continental slope setting controls the distribution of sand bodies in four-order sequences by means of controlling the Palaeogeomorphology and sedimentary source rechargement. According to the hydrodynamic characteristics and accumulation styles of the channel deposition，the sand bodies are further divided into the sub-erosion channel，migration channel and filling structure. Among them sub-erosion channel and filling structure have good reservoir conditions，that can be new gainful exploration targets.
The oil shale resources，which buried in 500～1 500 m，are about 6 813×108 t tones in China. The in-situ conversion process（ICP）is still in its infancy in China and were preliminary studied by oil shale pyrolysis，micropores and permeability experiments in different temperature. The oil shale pyrolysis is classified as 3 stages：dehydration，pyrolysis and mineral decomposition. During these stages，the physical and chemical reaction occurred in different，micropores and permeability of oil shale were evolved in different extent，of which the major changed is pyrolysis stage. We studied the temperature distribution of ICP with the unsteady mathematical model. It shows that the shale oil productions can begin after 5 years heating，the duration of productions maintains at least 2 years.
To solve the difficulty problems，which the stochastic geological model is uncertain，the paper presented the response-surface proxy model to carried out the uncertainties method and its research process. The uncertainties with the geomodel can’t be easily and correctly disclosed with respect to the process of the stochastically modeling that is limited by computer’s capacity and time consumption. In the whole process，some following crucial things should be considered seriously. All uncertainties with the geomodeling should be fully taken into account in compliance with the geological characteristics of reservoirs. Sensitivity analysis would be carried out prior to the generating of proxy model. The sampling algorithms for generating both the training and the validation models could be different from the predicating of the target through proxy model. The probabilistic distribution of the target variables（oil in place as an example）can be understood through proxy model to a great extent. Therefore，these stochastic geomodels can be picked out with respect to the probabilities in terms of the target. In this sense，risks and potentials for the development of a reservoir can be appraised further based on the uncertainty studies.
Water hydraulic fracture treatments are widely used in of exploitation for tight gas reservoirs such as shale gas because of its low cost and little damage to formation′s permeability. In the process of fracturing，turbulence effects，particle-particle and particle-wall interactions are important factors which affect proppant transportation and settling behavior. Because conventional proppant settlement calculation methods don′t consider the two-way coupling of fluid-solid and solid-solid，Euler-Euler twophase flow model is established to study the proppant transportation and settling behavior in the process of water-fracturing. Turbulence effects and friction stress between high concentration particles are taken into consideration to study the particlewall interaction，and Johnson-Jackson boundary conditions are also considered. By using this model，the two-phase flow of fracturing fluid and proppant in the slot under different inlet-velocity position，particle density are studied. The simulation results coincide with experimental results well，which verifies the effectiveness of the model used. In the meanwhile，the effect of these parameters to proppant transportation and settling law is also discussed in the paper.
Because the dynamic evaluation methods of CO2 miscible drive is not enough comprehensive and systematic，and also the improved water flooding chart is not suitable for the evaluation of the CO2 miscible drive，we first define the type A gas flooding characteristic curve. Then on the basis of it，we have derived the relational expression between the equivalent gas rate and recovery degree，and draw the calibration chart. We use this chart to predict the biggest increased recovery of Y block after injecting CO2，and by comparing with the scene results，we find that two of them are consistent. So the results that the chart is a good predictor of the biggest increased recovery after injecting CO2. In general，this method is more significant for the block’s further development.
At present，the calculation methods of stage injection-production ratio only considered a single factor，such as formation pressure or water cut；however，the stage injection-production ratio is controlled by many factors，such as formation pressure，water cut and cumulative water-oil production ratio in real development. To solve the problem，we derived the relationship formulation of stage injection-production ratio with cumulative oil production，formation pressure and water cut using the semi-logarithmical curve of cumulative water injection with cumulative oil production，combining the material balance equation of closed reservoir. Then two calculation formulations of stage injection-production ratio were further derived using the relationship formulation of cumulative oil production with water saturation and the two relationship formulations of relative permeability with water saturation. At the end，calculations of stage injection-production ratio using the above two calculation formulations for an example closed reservoir with water-injection development history showed that the new calculation methods are applicable and useful.
The pipe flow and reservoir fluid form a coupled system. Therefore，a mathematical model is proposed，which is capable of solving pipeline flow system and reservoir fluidity system. In pipeline system，Drift-flux model has been used to elucidate multiphases flow process with consideration of the influence of viscosity increasing of polymer solution. And Darcy laws have been used to describe reservoir fluidity system. On the basis of that，the decoupled solution has been given， the decoupled calculation has been completed by exchanging boundary conditions（wellbore pressure，multiphases flux and polymer concentration on perforations）. As a result，the convergence difficulties of coupled solution have been improved effectively. And the validity is verified by using business software. Results indicate that Drift-flux model can be effectively used to study the multiphases flow in pipeline with polymer solution；and the decoupled solution can efficiently solve the coupled flow process of pipeline and reservoir. Compared with the coupled solution，error is less than 5%. And the computing speed is 10 to 100 times of the coupled solution.
There are several vertical reservoirs in A Oilfield，and the greatly different reservoir physical properties，different fluid properties，and the disperse reserves. Because of these factors，in the cause of commingling water injection or commingling oil production，some problems caused by reservoir heterogeneity will gradually arise，which include serious injected water breaking through in single layer，quick increase of water cut，different reserves producing，unequal oil recovery and lower reservoir oil recovery. So how to improve the recovery is very important in the vertically heterogeneous reservoir. This paper uses numerical simulation technology to conduct the single and composite factor sensitivity analysis under the condition of commingling production by A oil field homogeneous model，and reservoir production characteristics，development evaluation and development index are compared in different development method by the actually heterogeneous model. In the end，we recommend technology development program practical in Oilfield，and put forward Oilfield development technology strategy and measures.
servoir is at the middle-later period of exploitation，calibrating and improving the recovery of the waterdriven sandstone gas reservoir and adjusting the development plan are very important. Before this，studying the residual gas can provide an accurate parameter for recovery calibration work. Adopting the co-current spontaneous imbibition experimental facility we tested the residual gas saturations of the sandstone samples from DH gas reservoir. The results revealed that initial gas saturation had an important effect on residual gas saturation，and porosity and permeability had a little influence on maximum residual gas saturation. The experimental results could coincide with Land’s model very well，but not with the Agrawal’s model. Based on the initial gas saturation of DH gas reservoir to the formula we calculated the residual gas saturation of DH gas reservoir. And by using the result of residual gas saturation we analyze the countermeasure of enhancing nature gas recovery of DH gas reservoir in the future.
In view of the factors that the diagenetic mechanism of volcanic reservoir is different from the conventional depositional sandstone reservoir，the micro-pore structure of the volcanic is more complex than that of sandstone reservoir. The movable fluid saturation of Xushen，Changling and Dixi volcanic gas reservoirs were systematically studied by using the centrifugal experiment，NMR，constant-rate mercury injection and CT technology. The experimental results indicate that the suitable centrifugal force used to obtaining the irreducible water saturation in centrifugal experiment is 2.76 MPa. The micro-distribution feature of the movable fluid corresponding to different permeability reservoir is different. The larger the permeability，the greater the proportion of the movable fluid controlled by the larger throat. 0.100 mD is one of the critical permeability values when the reservoir permeability larger or less than it，the micro-distribution feature of the movable fluid is different. The average of the movable fluid saturation of the three gas reservoir is 23.62%. The CT image and constant-rate mercury injection experimental results suggested that the reservoir fracture and pore-to-throat ratio are the main factors affecting the movable fluid saturation.
To solve the problem of proppant backflow during the flowback progress in fracturing at Sulige gas field，a kind of fracturing fiber was prepared. The suitable size and adding concentration in fracturing fluid were also determined in this paper. By simulating the model of enforced crack closure and the model of proppant sinking rate，we developed the optimization software of fibers anti-backflow of proppant，which could give useful messages for flowback of fracturing fluid and for controlling the proppant backflow. The testing results of fiber-added fracturing and controlled discharge show that the prepared fibers meet the need of anti-backflow of proppant in Sulige area. The use of fracturing fibers not only decreased the backflow but also increased rate of drain blowout；moreover，it also reduced the damage chance of needle valve and gate valve during the flowback.
The heavy oil relative permeability curve is an important parameter in heavy oil reservoir performance prediction. The error in the relative permeability test caused by experimental factors will result in wrong information for reservoir development analysis. Due to the long exit end pipeline and more dead volume in the high temperature relative permeability test，the oil-water phases flowing law in the exit end pipeline of core holder and method of dead volume calibration will have important effect on relative permeability experimental results. The phenomenon of non-piston like displacement and pressure hysteresis effect have been discovered based on the water flooding experiment of heavy oil in the exit end pipeline. The breakthrough recovery and ultimate recovery factor decrease with increasing oil viscosity and water drive velocity，and the metering oil volume is behind the data corresponding to the pressure. The conventional data correction by oil volume deducting space volume of pipeline may lead to the deviation of experimental results from the actual flow behavior，so a new method of data calibration is proposed.
The solid particles in the injecting water directly affect injection pressure and the degree of formation damage in low permeability sandstone reservoir. The paper studied the injection of three different sizes of solid particle，whose D90（the cumulative particle size distribution of solid particle in the injecting water exceeds 90%）is 1.24，5.05，9.91µm. and we studied three kinds of injectivity water for the degrees of damage on oil phase permeability，and investigate the impact on the recovery. The results show there are problems on injectivity in core of permeability less than 1 mD when particle size，D90，is larger than 1 µm. However，when the permeability of core is larger than 1 mD，the problem goes away. As D90 increases，the degrees of oil permeability damage increases and the water flooding recovery reduces. As the permeability grows，the solid particle of larger particle size plugs the flowing channel in small and medium-sized pores，reducing water-flood sweeping ability. Seen from chart of permeability damage，when the core permeability is greater than 10 mD，the particle size，D90，can be 5 µm.
In order to study the factors that affect the effect of barium sulfate scale inhibition，three kinds of scale inhibitors named ZX–101，TH–1 and TH–607B that resistance barium sulfate（strontium sulfate）were screened out to make experiments of temperature，salinity，concentration of Ba2+ and SO2-4 impact on barium sulfate separately by static scale inhibition method. The results show that these three inhibitors have shown great performance for barium sulfate scale，they can prevent scaling of barium sulfate effectively. Their inhibition efficiency first increase and then decrease with the increasment of temperature and salinity，and when the inhibitor concentration increases the inhibition efficiency increases. When the temperature is 65 ℃， SO2-4 concentration is 0.55 g/L，salinity is 73 g/L，inhibitor concentration is 0.1 g/L and the concentration of Ba2+ increases from 0.64 g/L to 1.28 g/L，these three kinds of scale inhibition efficiency gradually decrease，respectively from 96.55%，97.65%， 98.04% down to 82.80%，87.83%，84.49%. While Ba2+ concentration is 0.8 g/L，inhibitor concentration is 0.08g/L and the concentration of SO2-4 increases from 0.10 g/L to 0.60 g/L，their inhibition efficiency increase from 90.64%，96.49%，93.57% to 99.79%，99.28%，99.79%，and then begin to decline，eventually drop to 93.72%，91.09%，80.06%.
The heavy components of heavy oil have a great influence on the stability of emulsion. In this paper，taking heavy oil of a Xinjiang reservoir as an example，we assayed its basic properties such as density，viscosity，solidifyig point and acid value. After separated heavy oil into saturates aromatics，resins and asphaltenes by polarity separation，we tested the basic properties and element content of the four components，Asphaltenes can stabilize the interfacial film of emulsion，and the water extraction is at the minimum and stability of emulsion is at maximum when the asphaltene content is 0.5% and resin content is 4.0%. The small amplitude oscillation experiment tests on simulation oil emulsion interfacial rheological behavior revealed that in the resin/asphaltene model oil emulsion，complex modulus（E∗）increases first increased and then decreased with the passage of time. When the asphaltene content is 0.5%，the resin content is 4.0%，after 2 000 s the complex modulus（E∗）is at the maximum and the emulsion is stable.
Blooey line is the one of indispensable ground equipment in gas drilling，which has potential safety hazard in high pressure and high yield gas well drilling，but it is usually ignored in common. Because of solid particle erosion in high speed air flow，failure destruction of blooey line occurs mainly in bending joint. Based on erosion destruction of bending joint，we launch the study of erosion destruction mechanism and mathematical model，and carry on the theory discussion on erosion angle of attack，erosion function，erosion coefficient of particle shape and the stress of the solid particle. At the same time， this paper established the CFD finite element model and the angle of bending joint can change arbitrarily，which quantitatively simulates erosion rate of multiphase flow containing solid particles to blooey line bending joint under different conditions and do erosion mechanism research，and there is a series of CFD simulation study under the limitation flow rate（100×104 m3/d and 50×104 m3/d）in different sand content. Finally，obtained quantitative relation curves between erosion rate and the angle of joint，it provides the theoretical basis for the blooey line bending joint structure optimization in this paper.
With the rapid development of horizontal well drilling technology，the staged reservoir stimulation technology and supporting tools of horizontal wells has become increasingly popular. As a component of the staged reservoir stimulation tool to communicating reservoir and wellbore，shiftable sliding sleeves are used to stimulate reservoir and to improve oil，gas and water management throughout the life of the well. Because of the large shifting force and extended reach required to operate sliding sleeves in horizontals，the coiled tubing（CT）is typically used for sleeve management. But there is some uncertainty to ensure sleeve shifted successfully by observing the change of surface load and there is a possibility of misuse. At the same time， this method can’t determine the sleeve position，so if the operation is not fully in place，CT operation was needed again. To solve this problem，this paper introduces a new shifting tool which is connected by CT with fiber. This tool can shifting sleeve by locating sleeve position precisely and monitoring string load，pressure and temperature in the downhole；by processing and interpreting the measurement data on the ground，the operators can judge the situation downhole accurately and switch sleeves reliably. It also can determine sleeve position by the change of CCL curve to save a lot of cost and time caused by operational errors.
The particularity of the deep separate flood layer，the formation high temperature and the open hole completion in Tahe Oilfield’s Ordovician carbonate reservoir，the failure of open hole packer K341 in pre-injection test well cause the injection test failure. To analyze the reasons for the failure，the paper established the mechanical model of the ultra-deep pipe string of separate zone water injection and calculated the K341’s creeping quantitative relative to the casing packer with hydraulic anchor in different working conditions of the injection test pipe string and under the combined action of the mechanical effects. The results show that the K341 will produce 0.3∼0.6 m creep variable when the Y241 packer is in the process of setting after the K431 packer is worked and this directly causes the damage of the K341 packer. To solve the problem，we draw up the creep preventing technical measure of the ultra-deep open hole separate zone water injection pipe string and optimize structure of injection string. That is installation of bumper sub，optimization structure of packer K341 to keep the working pressure with packer Y241，installation of centralizers at both end of packer K341 to protect element when down to the wellbore.
To study the feasibility of non-repeating acquired time-lapse seismic reservoir monitoring，this paper uses 3-D Gaussian ray-beam forward simulation to simulate and analyze illumination of reservoir，quantifies the impact of different geometry parameters on bin-received energy of reservoir，and finds that the main factors affecting the magnitude and uniformity of bin-received energy of reservoir are distribution of offset and azimuth，namely the magnitude of max-offset and the number of receiver-line. When velocity variation of reservoir has less effect than geometry parameters variation on the magnitude of cell-received energy，it is more necessary to conduct the conforming matching for geometry of time-lapse seismic datasets. The key point in this step should be rebinning and matching of distribution of offset and azimuth in bins. It has proved to be able to efficiently reduce the seismic respond deviation in non-reservoir and amplify it in reservoir by geometry-matching for a set of non-repeating acquired real data from block S56.
To further study the gas source controlling factors of gas hydrate formation in Shenhu deep water zone of the northern in South China Sea，this paper focuses on the survey area of hydrate in Shenhu area，and analyzes the influence of various gas source supply conditions by the basic survey data and results of drilling in the area. The main results are as follows：（1）in the shallow area，about 400～1 200 m under the seabed，there are good conditions for biogenic gas formation and the potential Bio-gas source rocks，and it has great potential for the production of the biogenic methane gas；（2）in the deep area，the early Tertiary area，Wenchang Formation and Enping Formation are two main source rocks and can provide some thermogenic gas for gas hydrate formation；（3）Gas hydrate reservoir was formed in the deep areas，where deep thermogenic gas migrates upwards to shallow ground by faults or diapers，then，biogenic gas and thermogenic gas were enriched in the stability region of hydrate by lateral migration.
The Chinese marginal basin is located at the most active Cenozoic era，which is formed by the interaction of Eurasia， India-Australia and the Pacific plates，and its southern marginal basin is still subjected to the impact of the South China Sea cracking and expansion and many other factors，so the rift-depression double-layer structure basins have formed，which have different types，such as extensional or composite strike-slip-extrusion type. The sedimentation has filled in the basin，which is mid-deep lake face strata and hydrocarbon source rocks in the early phase of the Paleogene rift Valley，coal-bearing strata and hydrocarbon source rocks in the late phase of the Paleogene rift，and marine strata and hydrocarbon source rocks in the Neogene depression，which has laid a foundation for oil and gas formation. Due to the impact of the regional geological setting， the characteristics and thickness of the marginal basin crust has gradually graded features from the continental margin area to the deep ocean basin area. The basin subsidence deposition center has gradually migrated to the deep ocean basin，which results in the terrestrial heat flow and geothermal field increasing gradually to the ocean basin，coupled with the space-time mutual coupling configuration between advanced new tectonic movement and source supply system，which ultimately controls and restricts the law of oil and gas distribution and enrichment in marginal basin.
Based on previous researches of sedimentary structure of Changxing Formation，and combining with reorganization of sequence boundary，logging and lithology data，Changxing Formation in Jiannan Area has been divided into two three-order sequences and five fourth-order sequences，the development of reservoir and transverse distribution of sedimentary facies within fourth-order sequence in Changxing Formation have been studied in this paper. According to the calibration of fourth-order sequence on seismic section and time-slice map of strata，taking system tract of fourth-order sequence as mapping unit，the evolution of sedimentary facies is also discussed. The results indicate that the lower three-order sequence experienced three times relative fall of sea level，the organic reef and bank mainly developing in the stage of HST；in the upper three-order sequence，exposed organic bank with lithology of dolomite is widely distributed，but the scale is smaller than that of lower three-order sequence and the distribution range moves to the central part of study area gradually.
Shunxi Area of middle Tarim Basin is located in the northwest pitching end of Katake uplift. Lianglitage Formation reservoir of Ordovician is mainly fracture-cavity reservoirs. The studies show that cracks can be divided into the structural ceacks and non structural cracks. The structural cracks can be divided into vertical fractures，oblique fractures（high angle fractures，low angle fractures）and horizontal fractures；the non structural cracks contain pressure dissolved stitch seam fractures and diagenetic fractures；the oblique fractures is relatively more than vertical fractures and horizontal fractures，and trend of oblique fractures is mainly NW，NWW，followed by NE. Structural fractures have three stages of activities：late Caledonian— early Hercynian，late Hercynian and Indosinian—Yanshan periods. Further studies show that tectonic stress field， fracture，lithology，physical property and layer thickness is closely related to the crack. The crack growth is conteolled by local structural high，key parts，turning point，the junction of the brittle fracture，lithology，physical property and thickness of strata. Cracks in the area have very important significance in petroleum geology，which can not only be used as good reservoirs，and also favorable channel and in some extent it can expand karst effect；in the oil and gas migration and accumulation process， cracks are good oil and gas migration channel for karst effect，plays a vital role in oil and gas accumulation.
The exploration practice proves that the phenomenon of the oil and gas backflow exists in Chezheng Depression， the physical simulation experiments of the oil and gas accumulation confirmed that there are two types of oil and gas intrusion in hydrocarbon migration process，i.e. fracture as migration channel and the sand body framework as migration channel，the former is the important channel of the oil and gas backflow，however molecular replacement is the formation mechanism，and the oil and gas pool is of small size. the latter in sand body framework for migration of oil and gas intrusion，is that pressure difference controlling petroleum downward migration is an important driving force. The desired maximum pressure depends on the related physical property of sandbody，and it can form large-scale oil and gas reservoirs. The research provides theoretical support for the expansion of deep oil and gas exploration in petroliferous basin.
Evaluation on water flooded layer in the sandstone reservoir is a complex and difficult problem which has persecuted oilfield workers for many years. It is a new field of geochemical investigation for evaluating waterflooded layer by geochemical logging，which may be an effective and new way for finding residual oil in the secondary development stage. Based on the depth analysis on the mechanism of the watered-out oil layer，gas chromatogram，pyrolysis chromatography and coring data， the evaluation model of waterflooded layer and interpretation chart are established by calculating the parameter of porosity，oil saturation，oil displacement efficiency，and so on，which provides the quantitative calculation and qualitative identification for the evaluation method of waterflooded layer in the sandstone reservoir. The method is applied in the D group of C area in B Field of A Basin. The result indicates that the effectiveness is very great，with the agreement rate of 95percent compared with the result of well testing interpretation. The study revealed that the chemical logging method is applicable with great utilization value，which lay the foundation for the scheme adjustment and the enhancing oil recovery of the oilfield in the mid-late period of oilfield development.
For the fractured carbonate reservoir，fractures are effective reservoir space and primary channels. But the development of fractures is complex and the reservoir has strong heterogeneity. The normal geological modeling methods are not applicable to the fracture modeling. This paper takes X Oilfield in the Middle East Region as an example and establishes the technology of fracture modeling on a scale of fracture zones，medium-size fractures，and small-size fractures based on convergent multi-source information including geology，well-logging，seismic，and dynamic data. It is first proposed by the authors that the fracture reservoir facies model is established on the combination of the deterministic model and stochastic model method. Under the constraints of facies model，the development intensity bodies at different scale of fractures are established. Finally，a discrete fracture network（DFN）model and fracture property model are generated by means of DFN modeling and parameter field equivalence. In general，this paper discusses and studies a set of fracture modeling method converging with multi-source information on the basis of different scale of fractures for the complex carbonate reservoir.
With the well pattern successively infills，the distributing tend of reservoir sandbody is gradually determined，the distributing characteristics of sandbody in vertical direction can be accurately recognized according to the logging data，but that in horizontal direction is difficulty to be identified. Aiming at the problems of the heavy tasks and the ambiguity on the recognition of a single channel on well-tie sections，the technique of well-seismic and inversion to predict the boundary of a single channel in composite sand body was proposed in the paper，and the river channel boundaries were further proved by the logging curve characteristics. Four typical indicators of the single river channel in composite sand body are recognized on the inversion sections，8 synchronous but not simultaneous single channels are identified clearly by sandstone poor belt conditions of the seismic inversion plan. With the single channel recognition achievement，good effects are obtained on the injection-production relation and remaining oil tapping，which shows a good application prospect.
Xu 2 Gas Reservoir，which is in Xinchang Gas Field in western Sichuan Basin，is a typical low-permeability and tight clastic gas reservoir. Due to the complicated geological conditions and serious heterogeneity in this area，the gas-water layer distribution is very complicated，and the bound water’s content is high. The boundaries of resistivity between gas reservoir and gas-water layer are blurred，so that some mistakes arise in log interpretation. We use kernel principal component analysis and support vector machine，also known as KPCA–SVM model，which is based on particle swarm optimization（PSO），to solve the problem. Firstly，the model extracts non-linear properties of variables by kernel principal component analysis（KPCA）， and then inputs the properties of a variable into the support vector machine（SVM）. And in the identification process，we use the particle swarm optimization（PSO）to seek the optimization algorithm. Finally，the gas-water layer identification is implemented in the SVM. We applied this model to gas & water layer prediction of Xu 2 Member gas reservoir of Xinchang Gas Field，and the recognition result is in line with the actual situation of the study area.
Because of the many factors influencing the resistivity of carbonate reservoir and the complex conductive mechanism， it is difficult to identify the reservoir and interpret the property of fluids. On the basis of pore-structure physical model， we simulated the resistivity of reservoir，and analyzed the factors which affect the resistivity of reservoir. The factors include the throat size，the resistivity of formation water，and the resistivity of matrix，and the vuggy size，and so on. At last，the influencing degree to resistivity of reservoir is discussed and the reason of abnormal resistivity in carbonate is interpreted in this paper. The resistivity of reservoir gradually reduces with the throat diameter increasing，and increases as the resistivity of matrix and formation water increases. Vuggy extension influence on resistivity along the direction of the current is higher than that along the vertical current direction. With the vuggy size along current direction increasing，the resistivity reduces. The effect of throat diameter on the resistivity of reservoir is bigger than vuggy size. The effect of throat diameter on the resistivity of completely water-saturated rocks is bigger than on completely oil-saturated rocks，but for the resistivity of the matrix and the formation water，the extended direction and size of the vuggy，the condition is opposite.
Baimiao Gas Field belongs to a tight sandstone condensate gas reservoir which is characterized with complicated structure，deep burial，poor reservoir property，high content of condensate oil，showing small differential pressure，high formation pressure. Gas well fracturing stage generally has a higher capacity. But with the condensate blockage flow channel in the near wellbore area precipitation，the production fast declines and the stable production period shortens. The vertical well technology has been used in the development of the gas field，which is of low recovery degree and poor development effect. The development of horizontal well can increase the production rate and the recovery of gas reservoir. According to the geological characteristics of the gas reservoir，and through in-depth study of the geological characteristics，we recognize the local structure and the distribution rule of reservoir. Horizontal well test was carried out to study the development of this kind of gas reservoir. We optimized 2 horizontal wells and obtained initial effect which has a certain guiding significance for the rational development of tight sandstone gas condensate gas reservoir.
There is abundant petro-resources with great development potential in the ultra-low permeable reservoirs located in Ordos Basin；however，it is difficult to increase the production rate of single well drastically as the formation is of poor reservoir properties and strong heterogeneity. According to the characteristics of ultra-low permeable formation，the study is carried out focusing on horizontal well pattern，well drainage direction，parameters of horizontal section and producer-injector spacing，to establish the effective displacement pressure system. According to the studies，the research results show that the well pattern is the crisscross row pattern，which is the joint cloth well for the horizontal and vertical wells；the artificial pressure crack pattern is the dumbbell-shaped；the density of artificial fracture is 2/（100 m）；the length of horizontal section ranges from 700 to 800 m；the producer-injector spacing ranges from 700 to 800 m；the row spacing is about 150 m. Based on the research results for the horizontal well pattern design，the average initial production rate of single horizontal well in ultra-low permeable reservoirs is about 8.0 t/d，which is 4 times of the average production rate of vertical well. This proves that this method can improve the well production rate of ultra-low permeable reservoirs drastically.
The existence of start-up pressure gradient of reservoir has a great impact on the reservoir producing extent，the bigger the start-up pressure gradient，the poor the the reservoir producing extent. Based on the mechanism of fluid flow from the low permeability reservoir，the relationship between the start-up pressure gradient and permeability relationship of the study area were established by the in-situ early bound water production performance of single-phase data and well test material and well test method. we also analyze a typical well group pressure driven between the injection wells and production wells gradient features. By comparing values of reservoir permeability and reservoir fluid permeability values corresponding to the size，we determine whether the fluid within the reservoir may flow. This quantitative analysis of low permeability reservoir interwell reserves producing condition provides the reference for determining interwell residual oil distribution provides of similar reservoir.
Based on the reservoir architecture model of Gangdong Oilfield，the matching between lateral accretion shale bedding of point bar and flood pattern is analyzed. The effects of different well networks on the development efforts are studied respectively，including vertical well，horizontal well and sidetracking horizontal well. The results show that，a better development effect can be obtained with a low ratio of injection-production wells and the line of wells vertical to lateral accretion shale bedding when row pattern is utilized for exploitation. In horizontal wells development，when the horizontal section is perpendicular to incident lateral accretion shale bedding，remarkable effects can be achieved. The horizontal section should be keep away from injection wells when sidetracking horizontal wells were drilled out for potential tapping. In this study， remarkable potential tapping results were achieved when the horizontal section was three lateral accretion shale bedding away from injection wells，and horizontal section crossing with lateral accretion shale bedding at a 45-degree angle. The results of study are applied to completion of injection-production pattern horizontal wells and sidetracking horizontal wells with the good effect of oil increment.
