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01 January 2019, Volume 36 Issue 3 Previous Issue    Next Issue

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Conditions of Shale Oil Accumulation and Distribution of Favorable Areas in China YANG Weiwei, FENG Yuan, YANG Yong, FU Xiaoyan, FENG Yongjiu 2015, 36 (3):  1-1.  doi: 10.7657/XJPG20150301 Abstract ( 128 )   PDF (300KB) ( 155 )   Save Shale oil resources are rich in China. To clarify the petroleum geologic characteristics the shale oil accumulation conditions of China抯 petroliferous basins is of great significance for finding out the favorable distribution areas of shale oil reservoirs. The conditions of shale oil reservoirs include the large?scale organic?rich mudstone/shale layers with moderate thermal maturity and sapropelic kerogen that provide material for shale oil accumulation; the interlayers with relatively good permeability or shale with fractures that are favorable shale oil reservoirs. In China, the Paleozoic, Mesozoic and Cenozoic lacustrine middle?thick organic?rich mudstone/shale intervals are of better conditions for shale oil accumulation, which are the major domains of shale oil reservoirs, including Permian strata in Junggar and Santanghu basins, Triassic stratum in Ordos basin, Jurassic stratum in Sichuan basin, Cretaceous stratum in Songliao basin, and Paleogene strata in Bohai Bay, North Jiangsu, Jianghan and Nanxiang basins. Among them, the Triassic Yanchang formation in Ordos basin and the Cretaceous Qingshankou formation in Songliao basin are the best in shale oil geologic conditions Related Articles | Metrics

Geochemical Characteristics andOrigin Types of MidDeep Natural Gas in Dongfang AreaYinggehai Basin TONG Chuanxin1,2, MA Jian3, PEI Jianxiang2, XU Xinde2, LIU Ping2 2015, 36 (3):  1-1.  doi: 10.7657/XJPG20150302 Abstract ( 85 )   PDF (300KB) ( 192 )   Save In order to make clear the accumulation patterns of mid?deep natural gas in Dongfang area of diapir zone in Yinggehai basin,this paper studied the geochemistry, distribution of natural gas in high temperature and high pressure zone, and their relationship with gas accumulation based on the researches of diapir activity, using the geochemical analysis technology. The results indicate that there exist three types of thermogenic gases mainly generating from Meishan formation, including the matured coal?related gas, the high?matured and CO2?bearing coal?related gas, and the high?matured and CO2?rich coal?related gas; there are multistage mixed charging natural gases in high temperature and high pressure zones in diaper core and near it, which are characterized by strong late reworking, and there is a large amount of early charging gas in D13?2gas field; such a distribution and charging period in the diapir belt and surroundings are closely related to the diapir activity intensity differences. The influencing range of Diapir D1?1is about 10km, beyond which the quality of natural gas is getting better, and dominated by alkane?rich gas Related Articles | Metrics

Petroleum Geological Significance of Geochemical Anomalies in Meath Braque Area in Kuqa Depression, Tarim Basin LIN Yuxiang1, ZHU Chuanzhen1, ZHANG Gang2 2015, 36 (3):  1-1.  doi: 10.7657/XJPG20150303 Abstract ( 70 )   PDF (300KB) ( 170 )   Save By means of influence factors correction and trend fitting analysis methods, this paper studied the characteristics of geochemical background and geochemical anomaly distribution in Meath Braque area in Kuqa depression of Tarim basin. The results show that lines along Heiying?1well?Meath Braque?Carlo Kangxia, Sarah Hitam?Heiyingshan, and near Manchu Tamu have high value of geochemical explorative index, also they are the main distribution areas of geochemical anomaly. According to the anomaly level, combination and configuration relationship of the single geochemical index, it was divided into sixteen comprehensive anomalies. Based on the structural position, distribution and combination relationships of these geochemical anomalies, this area was divided into five comprehensive anomalies regions, among which there are only one most favorable area and two favorable areas. Integrated with the oil and gas geologic conditions in this area, it is suggested that the central annular anomaly zone could be the most favorable area for further petroleum exploration Related Articles | Metrics

Petroleumrderly Accumulationegularity and Exploration Significance in Kuqa Depression, Tarim Basin LIN Tong1,2, RAN Qigui2, ZENG Xu2, WEI Hongxing3, SUN Xiongwei3 2015, 36 (3):  1-1.  doi: 10.7657/XJPG20150304 Abstract ( 84 )   PDF (300KB) ( 236 )   Save The phenomena of associated coexistence of a variety of oil?gas reservoir types are more common in many basins. However, the current studies are only for a single type of reservoir in terms of petroleum existence or enrichment regularity. Taking Kuqa depression of Tarim basin as an example, the regional spatial distribution characteristics and rules of various reservoirs in this area were analyzed, and thought that the reservoirs in Kuqa depression have the rule and characteristics of petroleum“orderly accumulation”in regional and spatial domains. The orderly accumulation rule is mainly shown in three aspects:1) the order of the distribution of hydrocarbon components in different reservoirs; 2)the continuity of spatial distribution order of reservoir?forming dynamics, and 3) the order of the reservoir preservation mechanisms, all of which formed the associated coexistence of different types of reservoirs in space in Kuqa depression. This breakthrough of recognition is of great significance for further petroleum exploration in Kuqa depression. Related Articles | Metrics

Hydrothermal Processand Its Effect on Cambrian Carbonate Reservoirsin Tadong Area SHAO Hongmei1,2, LU Xi2, LI Guorong3, MENG Xianghao3 2015, 36 (3):  1-1.  doi: 10.7657/XJPG20150305 Abstract ( 58 )   PDF (300KB) ( 202 )   Save Hydrothermal activity played an important part in the formation of dolostone reservoirs in Tadong area (eastern Tarim basin). By applying the technologies of rock thin section microscopic identification, cathodoluminescence analysis, carbon and oxygen isotope analysis, trace element, rare earth element analysis, etc, the hydrothermal process and formed Cambrian hydrothermal dolostone reservoirs in Tadong area were studied. There are two stages of hydrothermal processes with transformed effect significance on the Cambrian carbonate reservoirs, and corresponding rock mineralogical and geochemical identification marks of the two hydrothermal processes are established. The Stage?Ⅰhydrothermal process took place in the Middle-Late Ordovician, its transformed effect on the Early Cambrian consolidateddolomites was dominated by formation of fractures rather than on the Cambrian microcrystalline limestone, marl and mudstone intervals. The Stage?Ⅱ hydrothermal process took place in late hercynian at the end of Permian, and its transformed effect created wide distribution of hydrothermal dissolution and formed Cambrian important dissolution fractured?vuggy reservoirs in this area Related Articles | Metrics

Application of Paleogeomorphic Genesis Assembly Identification Method to Recovery of Paleokarst Landform in Major Blocks of Tahe Oilfield, Tarim Basin CAO Jianwen1,2, XIA Riyuan2, ZHANG Qingyu1,2 2015, 36 (3):  1-1.  doi: 10.7657/XJPG20150306 Abstract ( 65 )   PDF (300KB) ( 237 )   Save In view of paleogeomorphology controlling the formation and distribution of karst reservoirs, this paper explored the application of paleogeomorphic genesis assembly identification method to restore the pre?Carboniferous paleokarst landform in the major blocks of Tahe oilfield. Firstly,4kinds of two?grade geomorphic units (karst platform, karst slope (upper), karst slope (lower), karst intermountain basin) are presented, and then landform identification factors are added to further divided the paleokarst landform into10kinds of three?grade geomorphic units, by which the identification precision of paleogeomorphic landform can be improved. Also, combined with the karst development features and hydrocarbon reservoir properties in micro?geomorphic units, the relationship between petroleum production and geomorphology is analyzed to provide powerful basis for prediction of karst reservoirs in Tahe oilfield Related Articles | Metrics

Characterization of Reservoir Rhythm and Application to Toutunhe Reservoir of Shinan21 Well Block in Junggar Basin JIANG Zhibin, FENG Lijuan, QIN Jianhua, LIU Wentao, QIAN Chuanchuan, LUO Zhixing 2015, 36 (3):  1-1.  doi: 10.7657/XJPG20150307 Abstract ( 57 )   PDF (300KB) ( 152 )   Save The water?flooded rules in Toutunhe reservoir of Shinan?21well block in Junggar basin are greatly influenced by reservoir rhythm. The bottom of positive rhythm zone is heavily water?flooded, the middle?upper part is weakly water?flooded, while the reverse rhythm area is overall heavily water?flooded. In order to find the reservoir area of positive rhythm with less water?flooded risk, the method of interlayer permeability ratio was adopted to confirm the critical value for reservoir rhythm classification, so that determine the positive?rhythm reservoir distribution area. Also, the model for prediction of the weakly water?flooded reservoir thickness was developed to further optimize the well locations and reduce the risk of adjustment. The methods for characterization of reservoir rhythm and prediction of weakly water?flooded reservoir thickness are of high probability and good agreement with the new adjustment wells, and can be applied to other massive sandstone reservoirs with low permeability Related Articles | Metrics

Structural Characteristics of Carbonate Platform Margins in Lower-Middle Ordovician of Tarim Basin and Related Hydrocarbon Implication MENG Xiangjie1, GAO Zhiqian2, FAN Tailiang2, LIN Jianpin1, LIU Tuanhui1, XI Zengqiang1, CUI Lihua1 2015, 36 (3):  1-1.  doi: 10.7657/XJPG20150308 Abstract ( 54 )   PDF (300KB) ( 240 )   Save The carbonate platform margins of Lower Paleozoic are an oil?gas enriched region. The seismic, logging, core and outcrop data from this area reveal that the structural types of the platform margins of Middle-Lower Ordovician in different areas in Tarim basin are big different. Tabei area (the northern Tarim) occurs in steep retrogradation rimmed margin type, Tazhong area (the central Tarim) in steep aggradation rimmed margin type, Taxi’nan area (the southwestern Tarim) and Awati area in weak aggradation?progradation ramp types, and Ta’nan are (the southern Tarim) is in weak aggradation?progradation steep?ramp type, with inheritance inter?platform slope facies. The comprehensive study of structure, deposition, paleo?environment and diagenesis, shows that:1) Tabei and Tazhong areas were located in the windward side with steep slope gradient of margins in Early-Middle Ordovician, and Taxi’nan and Awati areas were located in the leeward side with ramp slope gradient;2) Tectonic subsidence rate from platform to basin in Tabei area was fast when the synsedimentary occurred, the structures of platform margin were on style of retrogradation; while Tazhong area changed slowly, the structures on style of aggradation. It is suggested that the structures of platform margins are affected by paleoclimate and tectonic subsidence rate. The comparisons of carbonate platform margins are in favor of the reconstruction of lithofacies palaeogeography and the prediction of vertical?lateral distribution of favorable shoal reservoirs, and it is meaningful for petroleum exploration extension from platform margins to inner platform of Lower-Middle Ordovician in Tarim basin Related Articles | Metrics

Depositional Model for Lacustrine Beach Bars of Huangshanjie Formation in Tabei Area,Tarim Basin TANG Wu1, ZHONG Mihong2, TIAN Jianhua1, ZOU Mengjun1 2015, 36 (3):  1-1.  doi: 10.7657/XJPG20150309 Abstract ( 64 )   PDF (300KB) ( 131 )   Save To find out characteristics and controlling factors of beach?bar sand bodies in a terrestrial down?warped lacustrine basin is of great significance for lithologic reservoir exploration in it. In this paper, the characteristics of beach bars of transgressive systems tract and highstand systems tract of Huangshanjie formation of the Upper Triassic in Tabei area (northern Tarim basin) were analyzed in detail, based on the drilling, well log and3D seismic data. The results show that five microfacies are identified in the beach bars, including bar body, bar edge, interbar, beach sand and lake bay, with each microfacies having different sedimentary characteristics. The beach bars mainly develop in the northwestern and northeastern Tabei, dominated by northwestern Tabei on the plane, and in other areas they are isolated distribution. The formation of beach bars is closely related to the special paleogeomorphology setting, hydrodynamic environment, lake level change and provenance supply. Finally, based on the analysis of sedimentary characteristics, distribution and controlling factors of the beach bars, the depositional model for such beach bars in the down?warped lacustrine basin is established Related Articles | Metrics

A New Method for Calculating History Matching Precision of Reservoir Numerical Simulation YU Jinbiao 2015, 36 (3):  1-1.  doi: 10.7657/XJPG20150310 Abstract ( 56 )   PDF (300KB) ( 202 )   Save In view of the problem of hard to quantitatively calculate the history matching precision of reservoir numerical simulation at present, this paper presents four error characteristic values of history matching by in?depth analysis of the history matching errors, which can be used to quantitatively describe the characteristics of the whole history matching and display error distributions at each time period, and then a quantitative matched standard is established to evaluate the history matching quality of the reservoir indexes and single well indexes. Based on this standard, a new method for calculating history matching precision of indexes of reservoir and single well is proposed to quantitatively represent the precision of the history matching and evaluate the reliability of models. The case study indicates the practicability of the method Related Articles | Metrics

Adsorption Equilibrium Prediction of Shale Gas Pool Based on Adsorption Potential Theory WANG Qing, NING Zhengfu, ZHANG Rui, YANG Feng, ZHAO Huawei, L?Chaohui 2015, 36 (3):  1-1.  doi: 10.7657/XJPG20150311 Abstract ( 70 )   PDF (300KB) ( 218 )   Save Taking the Niutitang black shales of Lower Cambrian in Sichuan basin as an example, high temperature and high pressure isothermal adsorption experiments were conducted at35℃, 50℃, and 65℃. Based on the adsorption potential theory, the adsorption data were processed, and the adsorption potential and adsorption volume of methane on shales were calculated. Then the adsorption characteristic curves were plotted, from which the adsorption isotherms models were predicted. The results show that effect of temperature on the adsorption characteristic curves is greater, but such an adsorption is a physical one, its acting force is mainly dispersion force independent of temperature, therefore, the adsorption characteristic curves of methane on shales are of invariance of temperature, and the curves in different temperatures appear to be superposition each other. The adsorption prediction model can forecast gas adsorption capacity at other temperature and pressure conditions by adsorption data at one temperature as required. The case study indicates that the prediction results fit well with the experimental data, and the average relative error is less than3% Related Articles | Metrics

Optimization of Long Core CO2 Huff and Puff Experimental Parameters in Low Permeability Reservoir, Yanchang Oilfield HUANG Xiaoliang1, JIA Xinfeng2, ZHOU Xiang2, ZHENG Shanping3, YAN Wende1, YUAN Yingzhong1 2015, 36 (3):  1-1.  doi: 10.7657/XJPG20150312 Abstract ( 85 )   PDF (300KB) ( 281 )   Save By experiment of long core samples from low permeability reservoir in Yanchang oilfield, the effects of cyclic injection volume,soak time, pressure decline rate, gas injection process and gas injection rate on low?permeability reservoir development by CO2huff?n?puff process were studied. The results show that the first cyclic CO2 huff?n?puff is the key of production, its soak time should keep stable pressure followed by opening well for production, after which the production can be conducted without keeping stable pressure at any cycle.And appropriate low gas?injection rate may well overcome the influence of the model heterogeneity, hence reducing the negative impact of gas fingering on reservoir exploitation Related Articles | Metrics

Laboratory Experiment on Asynchronous Crosslinking System for Deep Profile Control CHEN ZehuaZHAO XiutaiWANG Zengbao 2015, 36 (3):  1-1.  doi: 10.7657/XJPG20150313 Abstract ( 64 )   PDF (300KB) ( 151 )   Save An asynchronous crosslinking system for deep profile control using organic chrome crosslinking agent and phenolic resin crosslinking system was developed . The following formula was screened out as the optimum system:5000mg/L HPAM+0.02%organic chrome +0.2%phenolic resin. The experiment results show that the first crosslinking time of the system is about30h, and the second crosslinking time is about 90h; the first crosslinking strength is0.02MPa, and the second crosslinking strength is0.062MPa. The influencing factor of the gelling properties of the system, including temperature, salinity and pH were investigated. The character of the system is that the total dosage of the crosslinking agent is low, and the cost is low; the viscosity of the system can increase quickly in short term through the first crosslinking, which inhibit the leakage of the gel and its infiltration into low permeable layers; the strength of the gel can be enhanced greatly through the second crosslinking. The system can be applied to the the strong heterogeneous formation with large pores or developed fractures Related Articles | Metrics

CBM Reservoir Characteristics and Productivity Prediction in Liulin Area ，Ordos Basin 2015, 36 (3):  1-1.  Abstract ( 61 )   PDF (300KB) ( 242 )   Save This paper analyzes the coal seam distribution，fracture development characteristics，roof?floor lithology，permeability，reservoir pressure，reservoir temperature，gas saturation，adsorption characteristics in Liulin area of Ordos basin. According to these parameters，this paper establishes the reservoir model. Integrated with the production performance，the reservoir model is adjusted after history matching by COMET?3. Finally，production prediction of Well L8indicates that the CBM cumulative production will be459.05×104m3 and the recoveryfactor will be56.12%in15years. The paper comes to a conclusion that the reservoir is favorable for CBM development，and CBM in Liulin area has high value for commercial development Related Articles | Metrics

Establishment of New Water Drive Characteristic Curve and Application in Xinjiang Oilfield GUO Feng1, TANG Hai1, QIU Zigang2a, WANG Yuhua2b, YAO Min2a, FAN Xibin2a 2015, 36 (3):  1-1.  doi: 10.7657/XJPG20150314 Abstract ( 57 )   PDF (300KB) ( 93 )   Save The water drive characteristic curves is widely used in water drive reservoir development, while most of the traditional water rive characteristic curves are single curve. In this paper, a new type of water drive characteristic curve is established based on two traditional water drive characteristic curves, and the dynamic data of Xinjiang oilfield development are fitted by nonlinearity using regression oftware, and the relationship graphics of cumulative production vs. water cut and water cut vs. recovery percent of recoverable reserves are lotted. The case study indicates that this new type of water drive characteristic curve is practicable and reasonable in prediction of water ut rising pattern, and it can not only be applied to common reservoirs at high water cut stage, but also applied to low permeability reseroirs at mid?high water cut stage Related Articles | Metrics

Unit Pressure Drop Method for Gas Production and Application to Gas Field Development YAN Zejiang1, QI Tao2, ZHOU Nan1, LIAO Wei1, DU Guo1, ZHANG Gangqing1 2015, 36 (3):  1-1.  doi: 10.7657/XJPG20150316 Abstract ( 87 )   PDF (300KB) ( 84 )   Save In order to understand gas reservoirs, find out the problems during gas field development and formulate the reasonable working system, the unit pressure drop method for gas production was proposed. Based on the principle of molar weight conservation, the material balance equations of the constant volume and abnormal pressure condensate gas reservoir were established, by which the expression of unit pressure drop for gas production was derived. The case study shows that the unit pressure drop for gas production appears increasing and then decreasing along with the pressure reducing, which is mainly related with propagation of pressure wave and deviation factor. By comparison of the actual curves with theoretical curve, we can determine if water invasion or other problems are happened. This method is simple in calculation and better in applicability Related Articles | Metrics

FactoryLike Drilling Technology of Cluster Horizontal Wells for Tight Oil Development in Jimusaer Sag, Junggar Basin WEN Qianbina, YANG Hua, SUN Weiguoa, CHEN Weifenga, ZHANG Ningb 2015, 36 (3):  1-1.  doi: 10.7657/XJPG20150317 Abstract ( 69 )   PDF (300KB) ( 161 )   Save The practical experiences of tight oil development abroad indicate that the combination of proper engineering technologies with factory?like operation pattern is an important tool for economic and efficient production of tight oils. Based on the characteristics of tight oil in Jimusar sag of Junggar basin, this paper recommended a factory?like drilling test of cluster horizontal wells as follows: 1)12wells in a drilling pad were arranged, the horizontal section extensions paralleled to the minimum principal stress orientation, and the distance between adjacent sections was 300m, with the horizontal?section lengths of1300m and1800m; batching drilling operation pattern was adopted, with3?well drilling for each of rig;2)five?section profile was used for three dimensional horizontal well in track design, realizing the fine track control by combination of screw rod directional tool with rotary steering drilling tool; 3)the optimization of wellhead spacing is run by hydraulic drive slide rail for quick rig moving; 4)constructing central treatment station to maintain or treat drilling fluid for increaseof repeating utilization factor of drilling fluid. Case study shows that the average rate of penetration of factory?like drilling can reach 9.19m/h, increased by5.87%compared with conventional drilling; the average drilling cycle is64.88days, shortened by19.65%; the repeating utilization factor of drilling fluid reaches28%. Hence using this drilling technology can effectively reduce the cost, improve efficiency and/or benefit Related Articles | Metrics

Fuzzy Evaluation Method forScreening Target Horizontal Wells in Heavy Oil Reservoirs by CO2Huff and Puff Process LI Yahui1, PENG Caizhen1, LI Haitao1, ZHONG Jibin2 2015, 36 (3):  1-1.  doi: 10.7657/XJPG20150318 Abstract ( 55 )   PDF (300KB) ( 132 )   Save Heavy oil exploitation benefit can be improved by CO2 stimulation process. Any horizontal well CO2 huff and puff should be selected by the geological conditions and performance of candidate wells. Combined with related data and numerical simulation results, comprehensive consideration of reservoir properties, fluid characteristics and horizontal well length, this paper put forward the horizontal well location selection evaluation index system and grading method suitable for heavy oil reservoirs by CO2 huff and puff process, and concrete approaches and steps by means of fuzzy evaluation theory and information entropy theory.31wells data of CO2 stimulation in X reservoir were used to verity the proposed method. The verification result is accordant with the actual situation, showing that the proposed method is feasible, and can provide reference and guidance for similar heavy oil reservoir development with horizontal well CO2huff and puff process Related Articles | Metrics

Application of Seismic Sedimentology to Organic ReefBank Body Identification in Y District LIU Ling1, WANG Feng2, LIU Yuxia3 2015, 36 (3):  1-1.  doi: 10.7657/XJPG20150319 Abstract ( 65 )   PDF (300KB) ( 235 )   Save Seismic sedimentology is applicable for prediction of plane sedimentary facies in isochronal element by means of seismic lateral resolution. It is applied to lithologic interpretation of the seismic profile without obvious characteristic changes. Y district is characterized by big buried depth of organic reef?bank body, low resolution of seismic data, not obvious reflection characteristics in the seismic profile. With the guidance of seismic sedimentology, this paper optimized the seismic attributes under the control of paleogeomorphology by using spectral decomposition data, qualitatively characterized the scale and boundary of the organic reef?bank body; and using double?plane interpretation method, verified the interpreted reef?bank body in which the plane attributes were projected on the seismic profile, thus largely reducing the multiplicity of solutions of geological bodies and improving the prediction precision of the reservoirs. Finally, by using colored inversion technique which does not depend on any model, the reef?bank reservoir’s thickness can be quantitatively predicted, and a set of technologies for prediction of organic reef?bank carbonate reservoirs is then established in this paper Related Articles | Metrics

Application of Techniques of Seismic Sedimentology for Nonmarine Basin in Pubei Area in Songliao Basin LU Husheng1, TANG Wenlian2, LI Peijun3, WEN Gangfeng4, LI Jun3, ZHANG Xianguo1 2015, 36 (3):  1-1.  doi: 10.7657/XJPG20150320 Abstract ( 76 )   PDF (300KB) ( 133 )   Save Seismic sedimentology is a new research field proposed during studies of the marine strata abroad in recent years, but its application to continental lake basins is urgently required to explore in technique. This paper analyzes the limitations of such three key techniques of seismic sedimentology as90°?phase conversion, strata slicing and frequency decomposition interpretation, and points out that the90°?phase conversion technique needs comprehensive consideration of the matched geologic body thickness and the frequency components of seismic data; strata slicing technique can be used for interpretation of sedimentary facies, but need to adopt different ways of slicing, according to different types of sedimentary facies;3D visualization sculpture technique of geological body can be applied to seismic sedimentology, solving3D interpretation problem of complex reservoir sediments Related Articles | Metrics

Confirmation and Significance of Lianglitage Formation of Upper Ordovician in Maigaiti Slope,Tarim Basin CAI Xiyao1, ZHAO Lina2, LI Huili1, ZHANG Zhili1, CHENG Junfeng2 2015, 36 (3):  1-1.  doi: 10.7657/XJPG20150321 Abstract ( 69 )   PDF (300KB) ( 303 )   Save Through in?depth analyses of the lithostratigraphy, biostratigraphy, logging stratigraphy and carbon and oxygen isotopes of the Ordovician from new wells in the Maigaiti slope, the Lianglitage formation of the Upper Ordovician in this area was confirmed to be unconformity contact with underlying Yingshan formation of the Middle?Lower Ordovician and overlying Yimugantawu formation of the Lower Silurian. The Lianglitage formation is dominated by grey, yellow?gray, brown?gray micrite, sand?cutting micrite, sparry grain limestone with thickness of90~140m, intercalated with a little purple calcareous mudstone, in which conodont biozone ofYaoxianognathus neimengguen sisoccurred and theδ13C in coring section ranges from0.3‰to0.9‰. Compared with the sections of Tazhong (down hole)?Bachu outcrop area, the Lianglitage formation lacks the lower part (4~5members). There existed three suits of favorable reservoir?cap rocks assemblages developed in the Ordovician strata in Maigaiti slope: a set of most favorable reservoir (Yingshan weathering crust karst?like grain limestone)cap rock (Lianglitage micrite) assemblage; a good reservoir (Lianglitage reef flats)?cap rock(Lianglitage reef cover micrite or Sangtamu mudstone assemblage; a favorable reservoir (Lianglitage grain limestone)?cap rock (Lower Silurian mudstone) assemblage Related Articles | Metrics

Opinions and Understanding on the Stratigraphic Subdivision of Kuishan Formation WANG Jingping1, LIU Huancheng2, LI Qitao2 2015, 36 (3):  1-1.  doi: 10.7657/XJPG20150322 Abstract ( 83 )   PDF (300KB) ( 124 )   Save On the foundation of clearing up Kuishan formation’s stratigraphic division, this paper makes observational study on the stratigraphic features in outcrop area and coverage area. Kuishan formation lithology is dominated by quartz sandstone with variegated shale and siltstone of varying thicknesses. There are four common rock types: multi?layered sand?shale interbed type, thick sand with thick mud type,upper thick sand?lower thick shale?bottom sand type, and single thick sand type. Kuishan formation in Shandong province was single thick sand type, whose definition is too narrow. This paper suggests that Kuishan formation should be redefined as stratigraphic unit which is dominated by thick hard dense (feldspar) quartz sandstone, with shale and siltstone of varying thicknesses, and the top takes thick hard dense (feldspar) quartz sandstone as boundary with Xiaofu River formation, the bottom boundary is taken by A0 bauxite layer or horizons corresponding to it. Such a definition of Kuishan formation is the same with the top and bottom boundaries of the production field, and helpful to maintaining continuity and succession of stratigraphic division data available and avoids a lot of rework in stratigraphic subdivision and correlation Related Articles | Metrics

Advances in Fan Deltaic Sedimentology ZHANG Changmin，ZHU Rui，YIN Taiju，YIN Yanshu 2015, 36 (3):  1-1.  doi: 10.7657/XJPG20150323 Abstract ( 99 )   PDF (300KB) ( 202 )   Save The advances about sedimentological study of fan deltas were reviewed based upon a great database of numerous research literatures at home and abroad，including 1)definition，classification and terminology;2)lithofacies and sedimentary sequences characteristics;3)depositional models and 4)research methodology. It is suggested that classifications for fan deltas should be more practical in their applications，the hydraulic and geomorphic parameters from modern delta front，and the most important rock characters from the ancient stratigraphic records should all be considered. The hydrodynamic principle should be involved in interpretation of the lithofacies of fan deltas.More studies are needed to analyze the controlling effects of tectonic movement，climatic vibration，sea/lake level changes and depositional autocyclic processes on the formation of fan dealtaic depositional sequences. Fan delta models type may increase with time and new methods such as flume experiment，computerized forward modeling and geostatistic stochastic simulation may be used more frequently in fan delta sedimentological research in the future Related Articles | Metrics

Gravity Flow Research Review and Gravity Flow Type of Baikouquan Formation in Mahu Slope Area KANG Xun1, JIN Jun2, HU Wenxuan1, YANG Zhao2, CAO Jian1, WU Haiguang1 2015, 36 (3):  1-1.  doi: 10.7657/XJPG20150324 Abstract ( 58 )   PDF (300KB) ( 401 )   Save The history and actuality of gravity flows researches at home and abroad were reviewed, including the gravity flow formation mechanism, sedimentary process and development sequence, etc., and the classification models and identification characteristics of gravity flows were analyzed, pointing out the possible gravity flow types in glutenite combination. Based on these results, the development characteristics and depositional fabrics of Baikouquan glutenite in Mahu slope area of Junggar basin were systematically observed and studied. It is suggested that five types of gravity flows, such as debris flow, grain flow turbidity current, flood mudflow and sandy debris flow, are mainly developed in the Baikouquan formation. According to the typical cores lithology descriptions, the identification marks for various gravity flows are presented, and the corresponding sedimentary sequence models are established in this paper Related Articles | Metrics