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01 January 2019, Volume 34 Issue 5 Previous Issue    Next Issue

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The Discovery, Characteristics and Prospects of Commercial Oil and Gas Layers/Reservoirs in Sichuan Basin LUO Zhili1, HAN Jianhui1, LUO Chao1, LUO Qihou2, HAN Keyou2 2013, 34 (5):  1-1.  Abstract ( 228 )   PDF (2515KB) ( 997 )   Save The oil and gas exploration efforts in Sichuan basin have been more than half a century. As a mature exploration or high mature basin, eight industrial/commercial gas reservoirs and one oil reservoir were found from the Late Proterozoic Sinian system to the Jurassic red bed, people called it“full basin gas and half pot of oil”, so Sichuan basin is a unique basin among petroleum basins in China. The discoveries and experiences of the oil and gas explorations are worth reviewing and summarizing, the hydrocarbon accumulation characteristics and prospects are worthy of probe and outlook, so as to strengthen the confidence that more oil and gas resources will be found. According to the experiences of the researches and explorations of the oil and gas fields in Sichuan basin, the authors consulted a large number of relevant information, analyzed the main characteristics and current situations of various industrial/commercial oil and gas reservoirs and accumulation, and put forward some conclusions and suggestions that Sichuan basin still has great oil and gas prospects, their exploration is promising, etc., which could be as references for the colleagues and decision makers Related Articles | Metrics

CoalForming Characteristics of Cenozoic Petroliferous Basins in Offshore China ZHANG Haitaoa,b, ZHU Yanminga,b 2013, 34 (5):  1-1.  Abstract ( 60 )   PDF (1926KB) ( 380 )   Save Starting from the basic factors affecting coal forming, this paper discusses the features of tectonic, climate, sediment and provenance, correlates the coal?bearing strata in Bohai Bay basin, South Yellow Sea basin, East China Sea shelf basin, the Pearl River Mouth basin, Qiongdongnan basin, Beibu Gulf basin and Yinggehai basin, and reveals the Cenozoic coal seam distribution characteristics in these China’s offshore basins. The results show that there are three coal?forming stages in these basins, with general environment for coal forming, numerous coal layer, thin thickness, low coal rank and local extension, and the coal?forming eras gradually become newer from north to south and from west to east, the main coal?forming stages are consistent with the tectonic events and the climate events Related Articles | Metrics

The logging Evaluation of Source Rocks in Permian Tight Oil Reservoir in Northern East Junggar Basin JIAO Cuihua1, WANG Qinghui1, XU Huaimin1, ZHAO Lei1, YI Zhen1, LI Lin2, WU Jian3 2013, 34 (5):  1-1.  Abstract ( 57 )   PDF (459KB) ( 183 )   Save The geochemical analysis data of the core and rock debris samples show that high quality lacustrine source rocks are developed in the 1st Member of Pingdiquan formation of Middle Permian in north of the eastern Junggar basin, with kerogen types ofⅠandⅡ1. In order to comprehensively understand and evaluate the source rocks, this paper develops proper the identification and evaluation methods of the source rocks in this area by means of the well log information calibrated by the core geochemical analysis data. The TOC of source rocks is calculated by many methods, such as the modified acoustic?resistivity superposition, the multifactor statistical regression, the petrophysical volume model of source rocks and the differences between the DEN porosity and NMR porosity. The relationship between pyrolysis hydrocarbon S2 and TOC is developed by the geochemical analysis data, by which IH is also calculated. And the source rocks maturity evaluation is based on the relationships between IH and thermal alteration index (ITA), ITA and Ro. Case study indicates that such methods are good for application, and can be as a powerful evidence for estimation of the tight oil resources amount in this area Related Articles | Metrics

The Effect of StrikeSlip Faulting Throw on Hydrocarbons in Northern Slope of Tazhong Area, Tarim Basin ZHANG Xinchao1, SUN Zandong1, ZHAO Junsheng1, PAN Yangyong2 2013, 34 (5):  1-1.  Abstract ( 70 )   PDF (1524KB) ( 265 )   Save Petroleum distribution in carbonate reservoirs of Ordovician in northern slope of Tazhong area are affected by N-E strike?slip fault, and the hydrocarbon enrichment is controlled by the fault throw. But the fault throw is difficult to calculate due to deep?buried reservoir, low resolution and signal to noise ratio of 3D seismic profiles describing the reservoirs distribution as well as the too?small horizontal fault throw and the varied vertical fault throw of this strike?slip fault. The further analysis of the 3D seismic data shows that the strike?slip fault was of the feature of N-W extension and formed extensional?apart regions with different widths along the fault strike. A method is then proposed in this paper for calculating the strike?slip fault width and height of extensional?apart regions to indirectly recognize and determine the fault throws. The results indicate that this method can be used to recognize the hydrocarbon distribution in this area, because of its high agreement to the strike?slip fault development regularity and good coincidence to the oil?gas distribution in this area Related Articles | Metrics

Analysis of Faulting Structure in Aman Area in Tarim Basin LIU Yalei1,2, HU Xiufang3, LIU Yunxiang4, WANG Yueran4, WEN Lei2, ZHANG Qiang2, LI Yuejun2 2013, 34 (5):  1-1.  Abstract ( 67 )   PDF (1828KB) ( 232 )   Save The fine seismic data interpretation shows that the Permian normal fault is mainly developed in Aman area in Tarim basin, and its tectonic style is dominated by "graben and horst"; the Cambrian-Early Ordovician stretching structure and the Middle?Late Ordovician compressional structure may also exist, but unable to be recognized on the seismic profiles due to late?stage destruction, all of which finally came to being a stabilized state in Cretaceous in the study area. It is suggested that the Cambrian stretching structure is related with the cracking of Rodinia supercontinent; the Middle?Late Ordovician compression structure is shaped due to the Caledonian-Early Hercynian collision orogenesis of the Kunlun mountains; Early Permian stretching structure is a product of the volcanic activities caused by mantle plume movements in the large igneous province. Contrastively, in the Cretaceous, the faults stop growing and the strata deposit stably into almost unchanged sizes in the study area. Finally, the structural evolution characteristics and the oil exploration prospect in Aman area are discussed Related Articles | Metrics

The Sedimentary Facies of Member-3 of Quantou Formation in Xinli Oilfield, Songliao Basin LI Junjun1, WANG Zhizhang1, ZHANG Zhihuan1, CHENG Guojun2 2013, 34 (5):  1-1.  Abstract ( 55 )   PDF (1183KB) ( 173 )   Save The systematic studies of the sedimentary characteristics, sedimentary microfacies and sedimentary evolution of the 3rd member of Quantou formation in Xinli oilfield of Songliao basin show that during the deposition of the 3rd member, the basement of this basin was in slow settlement and gentle terrain, and the meandering river sediments were formed under the background of alternating humid and arid climate appearance. This paper identified 6 types of sedimentary microfacies, such as point bar, abandoned channel, flood land, natural levee, crevasse splay, flood plain, and presents the plane graph of sedimentary facies, which could be as a geological basis for further exploration and development in this oilfield Related Articles | Metrics

Analysis of Main Controlling Factors of ReefFlat Karst Reservoir in Zhonggu15 Well Area in Tarim Basin WANG Zhenyu1, YANG Fei1, YANG Haijun2, PAN Wenqing2, SUN Chonghao2, LUO Yanan2 2013, 34 (5):  1-1.  Abstract ( 58 )   PDF (3361KB) ( 223 )   Save The Ordovician Lianglitage formation in Zhonggu?15 well area of central Tarim basin is of reef?flat karst reservoir, but different from other areas in this basin in horizon. It is mainly distributed in grain limestone bank of reef?flat facies of the third member of Lianglitage formation, and then in algal?laminated cryptite in lime mud mound. The main reservoir spaces consist of vug, cave and fracture, belonging to low?porosity and low?permeability reservoir. In accordance with the data analysis of the thin?section, diagenesis texture and microelements, it is recognized that the reservoir formation is closely related to the reef?flat karst and late burial karst reconstruction in the period of the third member deposition Related Articles | Metrics

Lacustrine Dolomitic Pattern of Permian in Fengcheng Area in Northwestern Margin of Junggar Basin YIN Lu1, QU Jianghua2, QI Liqi2, CHEN Yongbo1, XU Duonian1, WANG Bin1 2013, 34 (5):  1-1.  Abstract ( 71 )   PDF (1200KB) ( 229 )   Save The terrestrial lacustrine dolomite with dolomite content ranging from 15%~80% and 24% in average was found in Fengcheng area in northwestern margin of Junggar basin, which belongs to dolomitic rock or dolomite?contained rock, being greatly different from the typical dolomite in rock composition and genetic mechanism. Based on the rock?mineral, paleontological and geochemical characteristics of the dolomitic rocks, it is suggested that the dolomite of the Fengcheng formation was formed in the sedimentary environment with highsalinity, high Mg/Ca ratio and strong reduction. The laminated dolomite was formed in the penecontemporaneous period; while the dolomites in Xiazijie formatin and Wuerhe formation were formed by the fact that their magnesium ions were originated from the deep hydro?therm and the metasomatism caused with calcium ion in the early carbonate cements Related Articles | Metrics

Methods for Forecasting Development Index in Production Decline Stage CHEN Yuanqian, LI Jian, LEI Zhanxiang, LI Yunbo 2013, 34 (5):  1-1.  Abstract ( 100 )   PDF (431KB) ( 308 )   Save The production decline stage is a main stage of oilfield development, and forecasting oilfield development index in this stage is an important task for oilfield management. The main forecast methods include production decline method, forecast model method, water drive curve method and reservoir numerical simulation method, of which the production decline method is the most effective method. The method is independent of reservoir types and drive types, it can be used when an oilfield enters into the production decline stage. Based on the commonly used exponential decline principle, this paper proposed the methods for forecasting production, total cumulative production,total recoverable reserves, remaining recoverable reserves and reserve?production ratio of an oilfield in this decline stage. The case study shows that these methods are practical and effective Related Articles | Metrics

Well Pattern Adjustment of Thin and Bottom Water Reservoir with Low Magnitude and MidHigh Permeability in Luliang Oilfield, Junggar Basin CAO Wenjiang1, FAN Xibin1, XU Xuecheng2, SHI Guoxin2, LU Jianguo2, TAN Jianhua2 2013, 34 (5):  1-1.  Abstract ( 61 )   PDF (1962KB) ( 329 )   Save Based on the conventional well logging data of flooded layers interpretation from intensive translayer wells and injection?production interwell translayer wells in 2008—2012 in the thin and bottom water reservoir with low magnitude and mid?high permeability of Cretaceous Hutubihe formation in Luliang oilfield of Junggar basin, detailed reservoir geological model and numerical simulation model were developed, by which such problems as the size and extensional direction of thin mud and calcareous sandwich as well as the oil?water transi?tion zone were dealt with, obtaining satisfactory production history matching results and good agreement with the actual flooded location and thickness. And the remained oil distribution and waterdrive regularity of this reservoir are properly determined. Also, the reasonably optimizing well pattern adjustment mode for this reservoir is proposed for the first time. This will be helpful to the subsequent improvement of water flooding system, the waterdrive efficiency enhancement and EOR in this oilfield as well as a reference for study of similar reservoirs development Related Articles | Metrics

A New Method for Prediction of Volumetric Sweep Efficiency in WaterDrive Oilfield TANG Lin, GUO Xiao, DENG Qinyue, LU Jing, LENG Runxi 2013, 34 (5):  1-1.  Abstract ( 61 )   PDF (526KB) ( 178 )   Save In order to accurately and simply predict volumetric sweep efficiency, based on the characteristics of water?drive oilfield and the previous studies, a new relationship between volumetric sweep efficiency (Ev) and water cut (fw) under the various oil?water viscosity ratios is proposed and analyzed using Yu’s water?drive curve. And then, the three types of water?drive curves such as Type?C curve, Zhang’scurve and Yu’s curve are correlated by case study. The results show that when b ranges from 0.1 to 10, the Ev?fw relationship curve gradually changes from concave type to linear type, and when the fw reaches over 60%, the Ev amplitude increases; when the fw reaches over 80%,Ev curve appears in upwarp?like increase with the fw curve. It is concluded that the calculation method for volumetric sweep efficiency based on Yu’s water drive curve is better than those based on the Type C and Zhang’s water drive curves in application and precision Related Articles | Metrics

Application of Fiber Mixed Sand Fracturing in Karamay Oilfield ZHANG Jinga, LI Jiaqib, CAI Xianpinga, JI Yongjuna, XIE Shouchanga, CHENG Haoa 2013, 34 (5):  1-1.  Abstract ( 56 )   PDF (1292KB) ( 438 )   Save Based on the geologic characteristics of Karamay reservoir in Karamay oilfield, the full?range fiber mixed sand fracturing technology is designed as a measure for stimulation of next step. XJ?carbon fiber laboratory experiment was made for evaluation of the fiber transverse sand?consolidated property, vertical sand?suspended property and fiber?mixed proppant’s fracture long?term flow conductivity.The optimized fiber?mixed concentration of 0.9%~1.2% can completely meet the needs of the operating sand carrier, with little impact of its long?term flow conductivity. The selected domestic special fiber pump and its connection module reduce the cost, improve the precision and increase the efficiency. The cases study from 25 wells and layers indicates that the average daily fluid volume is increased by 3.2 times, the daily oil production increased by 4.4 times after fracturing measures than the measures before, with the incremental single well production of 325 t on average, the total incremental output of 8 130 t. The effect is remarkable Related Articles | Metrics

Application of Tomographic Static Correction Technoique in Fujin Basin LIU Yiwen, LIN Juan, YIN Lili, ZHENG Hongming, ZHAO Yong 2013, 34 (5):  1-1.  Abstract ( 58 )   PDF (5628KB) ( 346 )   Save In theory, the present tomographic static correction technique can be used to deal with the inversion of surface structure model under any complex surface condition. Because of the influences of field acquisition geometry design, initial model, equation solutions and smoothing factor, etc, the precision of tomographic inversion model and static correction still fails to meet the need of seismic imaging of such a complicated exploration area. Aiming at the problems of lower high?frequency precision, border effect and cross?point closure existed in application of tomography to complex surface area, this paper describes a series of methods applied in actual data processing, based on the surface structure characteristics in Fujin basin, and the distinctive effect indicates that the imaging quality of seismic data processing has been further improved, and the technique may be popularized for application to the other similar complex exploration areas Related Articles | Metrics

A New Method for Improving Fracturing Volume in UltraDeep Fractured Reservoir HAN Xiuling1, XIONG Chunming1, ZHOU Fujian2, ZHANG Fuxiang3, LIU Xiongfei2 2013, 34 (5):  1-1.  Abstract ( 67 )   PDF (1111KB) ( 312 )   Save Core mechanical experiment and block in?situ stress modeling along with theoretical analysis, numerical simulation and case study have been conducted to investigate the shear fracture mechanism of natural fractures during fracturing in ultra?deep fractured reservoir. It is suggested that natural fractures become shear failure when pore pressure reaches the natural fracture opening threshold, and the natural fractures with weak surface cementation and the dip angle of nearly 60° are more likely to happen for such a shear failure. Pumping pressure and pore pressure assume a relationship of linear increase, but all natural fractures are difficult to achieve fully opening. Hydraulic fractures tend to opening along natural fracture development segment in the current working conditions. The failure of rock is hard to make by fracturing and some natural fractures in a favorable orientation can not be opened. By optimizing pump rate, sand volume and pumping procedure, the stimulated reservoir volume or fracturing volume can be improved, and better results have been obtained in field application Related Articles | Metrics

Effects of ZeroOffset VSP Offset on TimeDepth Relationship LUO Bin, LUO Yong, JIANG Li, ZHENG Hongming, KANG Yueping 2013, 34 (5):  1-1.  Abstract ( 57 )   PDF (6068KB) ( 218 )   Save Conventional VSP offset correction is a method based on the premise of underground medium isotropic homogeneity, using distance relationship among wellhead, shot point and observation depth location to correct longitudinal time deviation caused by offset. With increase of anisotropy and decrease of observation depth, the corrected time error given by this method may increase and can not meet the requirement of the user on the VSP data accuracy. In this paper, a new offset correction method with the goal of horizontal homogeneous degree of reflection two?way travel time is presented, using the mid?value of travel time?depth curve before and after conventional correction to correct the time of VSP time?depth relationship. The case study shows that this method can improve the accuracy of the time?depth relationship, with error reduced more than 50% of the time. In addition, the geologic horizon calibration combined with time?depth curve can be used to quantitatively determine the intervals affected by the offset through determination of the critical travel time and critical depth,thus realizing more reasonable use of VSP data Related Articles | Metrics

The PreStack Depth Migration Velocity Model for Complex Geological Structure in Southern Margin of Junggar Basin: Modeling and Effect LUO Yong, ZHANG Long, MA Junyan, XIAO Lixin, LIN Juan 2013, 34 (5):  1-1.  Abstract ( 72 )   PDF (4504KB) ( 384 )   Save Dushanzi area in the southern margin of Junggar basin is characterized by complex near?surface structure, up?steep and down?gentle geological structure style, fault development and very complicated wave fields, which give rise to difficulties in the pre?stack depth migration in this area. This paper presents the key procedures for the seismic pre?stack depth migration velocity model (PSDM) applied in Dushanzi area: (1) making full use of well data to establish interval velocity map, and eliminate the influence of near?surface Xiyu conglomerate on the underlying interval velocity; (2) making restricted correction of the seismic velocity using drilled well velocity data and improving the accuracy of the velocity model with along?layer coherent inversion; (3) establishing the 3D velocity model based on the 2D grid to ensure the closure of space and time in 2D grid velocity field. The case study shows good imaging effects by using the PSDM technology Related Articles | Metrics

Application of FrequencyDivided Imaging Technique to Identification of Volcanic Eruption Cycles ZHU Chao1, HUANG Geping1, GONG Qingshun1, WU Yiping2, JIANG Junchao2 2013, 34 (5):  1-1.  Abstract ( 65 )   PDF (2998KB) ( 231 )   Save Volcanic rocks dominated by eruptive facies are developed in the third member of Aershan formation of Jurassic in Saihantala sag in Erlian basin, with thin thickness and few wells penetrating into the rocks. It is suggested from well data analysis that there exited four stages of volcanic eruptions in Aershan period. In view of the strong heterogeneity of such volcanic rock bodies, this paper presents the exploratory application of frequency?divided imaging technique to the identification of volcanic eruption cycles. By improving resolution of the seismic data, the scale and thickness of each eruption cycle are effectively predicted, providing a powerful support for petroleum exploration of volcanic reservoirs in this area Related Articles | Metrics

Acidification Effect Evaluation and Influencing Factors Analysis of Horizontal Gas Well with Heterogeneous Damage YUAN Lin1, LI Xiaoping1, XIAO Qiang2, SUN Fei3, ZHOU Changhong4 2013, 34 (5):  1-1.  Abstract ( 72 )   PDF (716KB) ( 204 )   Save Near the wellbore of a Horizontal well, there also exist damage zones, besides, it is in heterogeneous distribution and affected by the anisotropy of strata. Therefore, it may impact the productivity of the horizontal wells. This paper proposes a flowing physical model for the acidizing zone near the wellbore, based on the heterogeneous distribution of skin factor along the wellbore, by which a formula for the skin factor after acid treatment is given through considering the fact that the acidizing radius is greater or less than the radius of damage zone. According to the formula, the Joshi’s productivity formula is modified, meanwhile, the influences of horizontal section length, strata anisotropy coefficient, damage zone permeability and the maximum distance of mud immersion zone on the acidification effect are studied. It is concluded that horizontal section length, gas layer thickness, strata anisotropy coefficient, damage zone permeability and the maximumdistance of mud immersion zone are the main factors that affect increase productivity after the acid treatment of horizontal gas wells Related Articles | Metrics

Optimized and Fast Drilling Technology for Tight Oil Reservoir of Permian in Jimsar Sag in Junggar Basin JIANG Jianwei1, DENG Yi2, QU Gang1, XIN Fei1 2013, 34 (5):  1-1.  Abstract ( 66 )   PDF (450KB) ( 274 )   Save The tight oil reservoir drilling in Jimsar sag of Permian in Junggar basin is faced with several problems such as poor and slow rate of penetration, poor wellbore stability, serious blockage during tripping, etc. According to different geological conditions, a series of new drilling technologies were used to improve drilling speed in this area in 2012, including high?efficiency PDC bit, self?oscillating rotary percussion drilling tools, Torkbuster, etc, which allowed the drilling penetration rate to be improved and the complex damage rate to be decreased significantly or obviously Related Articles | Metrics

TubingCasing Annular Space in ESP Wells CHEN Dechun1, LI Ang1,2, GAO Li3, ZHU Zejun4, JIANG Dong4 2013, 34 (5):  1-1.  Abstract ( 69 )   PDF (963KB) ( 246 )   Save In view of characteristics of large discharge capacity, wide application and convenient management of electrical submersible pumping (ESP), combining with poor lifting efficiency and low wellbore flowing in deep heavy oil reservoir, the technology for blending light hydrocarbon above pump in tubing?casing annular space in ESP wells is studied. The influences of the thermolysis of submersible motor, cable and parameters of blending light hydrocarbon are comprehensively considered. According to the law of the conservation of heat energy, a temperature calculation model for blending light hydrocarbon above pump in tubing?casing annular space in ESP wells is developed.The influences of temperature and volume of blending light hydrocarbon and diluting depth on the temperature distribution of wellbore mixed fluid are analyzed. The study shows that with increasing of temperature of blending light hydrocarbon, the temperature of output fluid closed to the wellhead increases, it is favorable for surface transportation of crude oil. With increasing of the volume of blending light hydrocarbon, the temperature of output fluid closed to the wellhead increases, while that of closing to diluting depth decreases slightly. Output fluid temperature also decreases slightly with the addition of diluting depth, but almost maintains from diluting depth to wellhead. This study has important values of theory and application for optimization of such lifting technology parameters Related Articles | Metrics

Analysis of Geological and Geomorphic Features and Possible Risk Factors of Rili-Lufeng Segment in ChinaBurma Oil Pipeline MA Xiaoli1, ZHU Yun2, ZENG Xin1, HUANG Cheng1 2013, 34 (5):  1-1.  Abstract ( 97 )   PDF (1261KB) ( 158 )   Save The geomorphic types of domestic segments along China?Burma oil pipelines appear in mountain, hill, plain and mountain valley, etc., across multiple drainages and rivers, characterized by complicated terrains and drastic ups and downs. The regional tectonic locations of the segments are in less stable and unstable areas, some in active fault zones, with obvious surface dislocation and earthquake geological tectonic conditions. Most segments of the engineering geology have highly corrosive soils. The investigation and analysis suggest that such natural disasters may possibly occur as earthquakes, landslides, mud?rock flow, collapse and landslips, ground subsidences, flooding,soil liquefaction, etc. These unpredictable disasters will be the nonnegligible risk factors after Rili?Lufeng oil pipeline goes into operation Related Articles | Metrics

The Sustainable Development of Daqing Oilfield Needs Support of New Theory of Oil Generation LI Ruyi, GUO Zhanqian 2013, 34 (5):  1-1.  Abstract ( 74 )   PDF (1766KB) ( 292 )   Save A sustainable development of an oil and gas field needs a continuous supply of oil and gas sources, so does the Daqing oilfield.The exploration practices show that there exists biogenic oil ? gas supply in Daging oilfield, because, its volcanic activity surrounding Songliao basin is very activ. So Songliao basin is a basin of igneous rock intrusion. The volcanic or igneous rocks can be taken for granted to transport oil and gas originated by volcanic activity to Songliao basin. Also, the crude oil with color like quartz inclusions“oil” contains some“elements” that do not exist in biological or organic materials found in Daqing exploration area. All these indicate that there exist abiogenic or inorganic crude oils in this area, which provides theory and the practice supports for the sustainable development of Daqing oilfield Related Articles | Metrics

Distribution of Tricyclic Terpane and Sterane with Application to OilSource Correlation in Southern Turgay Basin CHEN Anding1, ZHAO Junfeng2, QI Jianhua3, SHAO Manjun3 2013, 34 (5):  1-1.  Abstract ( 82 )   PDF (2260KB) ( 375 )   Save The source rocks of Aryskum depression in southern Turgay basin are mainly in Middle?Lower Jurassic, which contain three types of kerogen, i.e. humic?sapropelic, sapropelic?humic and humic ones, being at low mature?mature and locally high mature stages. Aryskum depression has a structure in alternative arrangement of sags and swells, in which oil and gas generally occur in sags with multiple sets of sources rocks and store in swells. So the oil sources is difficultly distinguished by the difference and similarity of sedimentary environment and kerogen properties between the sags and the strata. According to the data analysis, sterane in the crude oil is divided into four distribution types of Ⅱ1, Ⅱ21, Ⅱ22, III and tricyclic terpane into two series with 11 distribution types. Using "the unknown peak" of tricyclic terpane to distinguish source rocks in different sags and using distribution assembly of sterane?tricyclic terpene to find out specific position of the source rocks, by which the oil?source distinguishing problem is successfully solved Related Articles | Metrics

Formation Conditions and Segment Corelation of the Giant OilGas Fields in Passive Continental Margin Basins in West Africa WEN Zhixin1, WAN Lunkun1, WU Yadong2, HE Zhengjun1, WANG Yonghua1 2013, 34 (5):  1-1.  Abstract ( 79 )   PDF (1916KB) ( 783 )   Save Based on plate tectonics theory and various useful information or data, this paper presents the formation and evolution procedures of the coastal prototype basins in West African, the stage correlation of paleo?sedimentary environment changes and their controlling effects on the giant oil?gas fields’formation conditions, and develops the hydrocarbon accumulation modes for the giant oil?gas fields in such three stages and four types of basins. It suggests that the three? segment basins in this area underwent three prototype stages such as the Late Jurassic?Early Cretaceous intra?continental rift stage, the Early Cretaceous intercontinental rift as a transition stage and the Early Cretaceous passive continental margin as a drift stage in West Africa. In the south segment formed the rift sequence structural?lithologic mode, due to little passive continental margin sequence; in the middle segment, the salt?bearing basins were characterized by transitional intercontinental rift halite, with the upper and the lower drift marine and rift lagoonal sediments which are all as premium source rocks,whereas the halite and marine shale as premium cap rocks, forming“dual?source and dual?seal”mode; in the north segment, the transitional basins were of great thickness of drift marine sediments, where narrow shelf and steep slope gave rise to drift turbidite sand bodies mode. Also, Niger delta basin with the unique high construction base formed“delta turbidite sand body”mode, in which the inner?ring rolling anticline belt is of the richest oil and gas, and giant oil?gas fields have been found in the turbidite sand bodies in the central anticline belt with muddy anticline belt and the outside?ring thrust and compressional anticline belt Related Articles | Metrics

The Seismic Velocity Modeling Technology in the Salt Region,Red Sea Basin: Study and Application ZHANG Yonggang1, ZHUANG Xijin1, L? Fuliang1, FAN Guozhang1, WANG Haiying2 2013, 34 (5):  1-1.  Abstract ( 60 )   PDF (3416KB) ( 194 )   Save Salt stratigraphic development is one of the main features in the Red Sea basin, which is characterized by coastal salt layer affection by proximal sediments, the mixed sediments of evaporates and sandstones/mudstones with the stratified shape. Due to salt’s fluidity and overlying unequal pressure, the salt layer was deformed, forming giant salt domes and swells and the content of evaporate is relatively higher. Four key technologies are applied for the salt layer’s velocity fine modeling in the salt basin region. The anomalous value’s elimination of stacking velocity spectrum ensures the accurate development of the velocity model. The split processing of salt layer with upper piercing formations guarantees the conterminous conformability of velocity and salt layer interfaces. The correction of pseudo?well computed velocity on the velocity model assures the rationality of the velocity field. The interval velocity forward simulation confirms the velocity model’s feasibility. Through the study and application of the salt region’s velocity modeling technology, the pre?salt structure reliability,trap scale and closure can be effectively identified, which are of great significance in the early stage of complex salt basin exploration Related Articles | Metrics

Crude Oil Characteristics and OilSource Analysis of Mesozoic in the North Yellow Sea Basin Crude Oil Characteristics and OilSource Analysis of Mesozoic in the North Yellow Sea Basin 2013, 34 (5):  1-1.  Abstract ( 79 )   PDF (1484KB) ( 196 )   Save The North Yellow Sea basin is one of China’s low degree of prospecting area where the crude oil found at present is produced in Lower Cretaceous. It has the characteristics of high density, mid?high wax and low sulfur, belonging to typical lacustrine mature crude oil, without obvious biological degradation. The GC, GC?MS and carbon isotope composition analyses of the crude oil and the Middle and Upper Jurassic source rocks are conducted and the oil?source correlation is made in this paper. The results indicate that the characteristics of the carbon isotopic composition, isoprene, terpane and sterane biomarker, stable carbon isotopic compositions of the individual n?alkanes are different from the Middle Jurassic source rocks. The crude oils could come from the lacustrine mature source rocks with good kerogen type and parent materials dominated by low aquatic organisms Related Articles | Metrics