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01 April 2008, Volume 29 Issue 2 Previous Issue    Next Issue

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Re-Understanding of Some Problems about Petroleum Migration and Accumulation LI Ming-cheng 2008, 29 (2):  133-137.  Abstract ( 103 )   PDF (1048KB) ( 204 )   Save In a primary subsiding hydrocarbon generative basin, the migration or accumulation of hydrocarbon is an episodic and continuous differential process that accomplished in (20~40)×106 a. Darcy flow and diffusion flow have the flowing rate in mudstone at 3~5 m/106 a and 4~18 m/106 a, respectively, they can occur at the same time and convert each other. The premium pathway and the direction for petroleum migration are different in concept, the former is controlled by rock make-up, and the latter is controlled by sedimentary facies and structural feature. The preliminary study shows that over 70% of oil and gas fields are located on the direction of premium pathway for petroleum migration. The sealing intensity and closure of trap are divided into three types of combinations, which are the main control factors for in-situ oil-gas distribution. The sand lenticular body-formed reservoir is resulted from multi-dynamic interactions and multi-phase state conversions and closely related to the quality and thickness of muddy source rocks as well as the sand physical property and occurrence. The study shows that the global oil reserves age and the giant oilfields median age are 29×106 a and 35×106 a, averaging 41×106 a and 55×106 a in existing age, respectively; Big-and medium-sized oil fields and gas fields average 120×106 a and 70× 106 a in natural forming age, respectively. References | Related Articles | Metrics

Structural Evolution and Petroleum Accumulation in Luliang Uplift, Junggar Basin QU Guo-sheng, MA Zong-jin, LU Bing, ZHANG Jin, ZHANG Ning, TIAN Ye 2008, 29 (2):  138-142.  Abstract ( 127 )   PDF (1046KB) ( 369 )   Save Based on the analysis of five sedimentary-tectonic zones and fault systems, this paper discusses controls and framework of the Early Permian basement fault on depression of multi-stage cap rocks in Luliang uplift of Junggar basin. It is determined preliminarily that the fault system of Luliang uplift is composed of Sangequan-Lunan and Dishuiquan-Shixi dextral oblique strike-slip fault belts. The caprock fault is controlled by the basement fault in Luliang uplift, forming the arcuate tree type fault system dominated by Sangequan and Dishuiquan oblique strike-slip systems near EW direction. Luliang uplift can be classified into 2 first-class structural units, 6 second-class structural units, 15 third-class structural units and 26 fourth-class structural units. Sangequan and Dishuiquan deep lithospheric strike-slip fault systems could be as pathways for hydrocarbon accumulation. Some small folds in dextral distribution along the upper wall of NE faults might become spaces for petroleum accumulation. The regulation of hydrocarbon migration and accumulation in Luliang uplift assumes tree type thermal supplies from deep crust, oil-gas migration from south to north and segmented accumulation along the uplift. References | Related Articles | Metrics

Study on Basin-Range Coupling Along Northwestern Margin of Junggar Basin XU Jian-dong, MA Zong-jin, QU Guo-sheng, LI Jun 2008, 29 (2):  143-146.  Abstract ( 93 )   PDF (568KB) ( 386 )   Save Based on the field survey and combined with the results interpreted from the artificial seismic exploration along the line between Karamay and Emin, the basic structural model of basin-range coupling along the northwestern margin of Junggar basin is discussed, showing that in section, it is a large double-thrust system with great complexity; in plane, this NE-trending structural zone is separated into 3 segments and 12 sub-segments by the segmentation indications proposed in this paper. The comparison between sedimentation and tectonic feature for different segments suggests that the thickness of sediment layers varies greatly in the sedimentary cap rocks; the tectonic segmentation of front thrust belt behaves both in time and in space, which exhibits not only in 3 segments, but also in 12 sub-segments. Finally, the relation between the oil-gas fields and the basin-range coupling structural model is discussed, pointing out that NW-trending cross fault and the 3rd NE-trending structural belt are of important significance in oil-gas potential prediction in this area. References | Related Articles | Metrics

Major Controlling Factors and Exploration Directions of Stratigraphic Reservoirsin Junggar Basin LIU Chuan-hu, ZHUANG Wen-shan 2008, 29 (2):  147-151.  Abstract ( 99 )   PDF (497KB) ( 220 )   Save Junggar basin is a composite basin superimposed by different kinds of proto-type basins with well developed stratigraphic reservoirs. Four types of stratigraphic reservoirs mainly exist in this area such as stratigraphic overlap reservoir, truncated stratipraphic unconformity reservoir, downcutting channel sand reservoir and basement buried hill reservoir, which are characterized by various types, large scale, multi-strata and paleogeomorphology-controlled time-space distribution. The major controlling factors for these stratigraphic reservoirs in this basin include multiple high-quality source rocks, unconformity transporting capacity, high quality reservoir belts and multistage tectonic movements. The stratigraphic reservoirs are classified into two reservoir models. One is "near source and selfgeneration" and the other is "far source and mixed genration". It is concluded that the uplifts in inner and surrounding Junggar basin are favorable exploration targets to find out large-scale stratigraphic reservoirs. References | Related Articles | Metrics

Deep Hydrothermal Activityvs Petroleum Origin in Jiuxi Basin SHI Lan-ting, WANG Bin-ting, ZHENG Rong-cai, ZHANG Jing-lian 2008, 29 (2):  152-154.  Abstract ( 101 )   PDF (257KB) ( 203 )   Save Following the development of several decades, Yumen field in Jiuxi basin has not been depleted. Recently, Liugouzhuang-Kulongshan field is discovered and its origin of petroleum causes concerns. The study shows that there exist dolomite, albite, illite and lots of metal hydrothermal minerals in Xiagou formation of Lower Cretaceous in Qingxi sag of Jiuxi basin. It is a deep hydrothermal activity with abundant alkali and hydrocarbon mantle fluid. The geosciences transect research reveals that a low-velocity and highconductive layer occurs in the mid-crust of Jiuxi basin. The Pb isotopic geochemical mapping suggests that Jiuxi basin is located on highly changing zone in Pb isotopic geochemistry. These features indicate that Jiuxi basin is an area with strong crust-mantle interaction, and its petroleum could be originated in inorganic origin. Such an idea means that Jiuxi basin will be better prospective in petroleum exploration in the future. References | Related Articles | Metrics

Hydrothermal Activities vs Coal Origin in Ruqigou Coal Mine ZHANG Hu-quan, ZHANG Jing-lian, WEI Ping-sheng, CHEN Qi-lin, WU Wu-tong 2008, 29 (2):  155-158.  Abstract ( 101 )   PDF (278KB) ( 236 )   Save The hydrothermal activities including quartz vein (silication), dolomitization, chloritization, illitization and pyritization and the widely distributed basalt in Ruqigou coal mine in western margin of Ordos basin indicate that there exist mantle fluids in the basin since it is in rifted environment. And the geoscience transect reveals that there is a low-velocity and high-conduction layer in the deep crust of the basin, which contains abundant Na+ , K+ , Mg2 + and Hydrocarbons. These constitute the main components of coal and form highmetamorphic anthracitic coal. It is concluded that coal is not only formed by plants, but also by deep mantle fluids. References | Related Articles | Metrics

Characteristics of Bitumen Trace Elements and Rare Earth Elements of Coal in Southeastern Margin of Ordos Basin LI Hong-ying, HE Ying, YANG Lei, LIU Yang-jie 2008, 29 (2):  159-162.  Abstract ( 101 )   PDF (373KB) ( 227 )   Save Chloroform bitumen A has been extracted from coal and coal gangue in southeastern margin of Ordos basin. The trace elements and rare earth elements in it are tested and analyzed, which provide some geochemical information for revealing the geochemical characteristics of coal in this area. The study suggests that the original materials for forming coal in southeastern margin of Ordos basin are most likely from the upper crust. References | Related Articles | Metrics

Log Description for Reef Flat Reservoir—An example from Tazhong No.1 slope break XIAO Cheng-wen, ZHU Xiao-min, HAI Chuan, LI Jin-fu, LIU Xing-li, WU Yuan-dong 2008, 29 (2):  163-165.  Abstract ( 108 )   PDF (773KB) ( 419 )   Save The lithology of reef flat reservoir of Upper Ordovician in Tazhong No.1 slope break is dominated by carbonate rocks with variety and complexity of spaces of reservoir, which brings about difficult evaluations of it using well log data. This paper presents the space type and the reservoir type by means of log data integrated with core, experiment and well test information, including corresponding response characteristics and response models to calculate the pore parameter, fluid property and hydrocarbon saturation of each type of reservoir, thus realizing characterization and quantitative evaluation of such reservoirs. With these techniques, the coincidence rate of well log interpretation is improved from 65% to over 90% , and many old wells have acquired high production by reinterpretation. The recalculated parameters of reservoirs allow this area to add additional hundred-million-ton reserves. References | Related Articles | Metrics

Sequence of Diagenesis Evolution of Upper Ordovician Carbonate Rocks in Tazhong Oilfield, Tarim Basin ZHOU Bo, JIA Cheng-zao, GU Jia-yu, LI Qi-ming, WU Guang-hui 2008, 29 (2):  166-169.  Abstract ( 130 )   PDF (893KB) ( 225 )   Save Some high-quality reservoirs exist in Lianglitag limestone member of Upper Ordovician in Tazhong platform margin in Tarim basin, which have become significant targets for petroleum exploration breakthrough in recent years in this area. This paper presents indepth study of diagenesis evolution of the carbonate sediments in lithology and sedimentology, including the establishment of relevant lithology identification standards for each diagenetic stage and the cross section of diagenesis evolution for coring sections of single well as well as regional distribution and abundance of cements in various diagenesis stages and their variations of diagenesis. The results are helpful to research the controlling factors of reservoir development in this area. References | Related Articles | Metrics

Mechanism of Episode Petroleum Migration Along Faults Down LUO Qun, SONG Zi-xue 2008, 29 (2):  170-171.  Abstract ( 103 )   PDF (488KB) ( 205 )   Save The analysis of fault activity and hydrocarbon migration and accumulation in Fuyang reservoir in northern Songliao basin suggests that this reservoir could not be explained simply by overpressure allowing hydrocarbon to migrate down along faults rather than by the model of intermittent overpressure releasing along faults and episodic counterflow/accumulation, which is the main reason of mature hydrocarbon from Qinshankou source rock migrating down along faults for a long distance. Such a model can not only explain that it is the fault that carried the oil and gas migrating down in condition of overpressure, but also provides theoretic basis for petroleum long-distance counterflow migrating down along faults. Also, it is pointed out that the underlying strata and the deep strata with overpressure in this area are favourable for petroleum exploration. References | Related Articles | Metrics

Petroleum System in Yanqi Basin MA Qiang, YAO Ya-ming, JIN Wei-ping, ZHANG Qin-fu 2008, 29 (2):  172-175.  Abstract ( 145 )   PDF (456KB) ( 153 )   Save Yanqi basin is a Mesozoic-Cenozoic coal-bearing basin formed on the Hercynian folded basement. Based on the basinal evolution, hydrocarbon source rock condition, reservoirs, cap rocks, reservoir-cap rock assemblage and trap types, this paper suggests that there are two major petroleum generation and accumulation events in this basin. The Jurassic petroleum system occurs in Bohu depression which can be divided into the northern sag petroleum system and the southern sag petroleum system in plane and into Jurassic primary petroleum system and Tertiary secondary petroleum system in longitudinal direction. References | Related Articles | Metrics

Hydrocarbon Accumulation Stages and Model of Shizigou Structural Oilfield in Western Qaidam Basin LI Yan-jun, JIANG Bo, ZHANG Yong-xi, SI Dan, HAO Xiao-mei, ZHANG Yong-mei 2008, 29 (2):  176-178.  Abstract ( 101 )   PDF (620KB) ( 280 )   Save This paper affirms the hydrocarbon source, studies the fluid inclusion and homogenization temperature based on the source rock thermal evolution and reservoir geothermal history in Shizigou field. By means of staging theory of petroleum generation, migration and accumulation, it is suggested that there exist three stages of hydrocarbon accumulations in Shizigou structure, they are E3 2, late N2 1 and late N2 3, which correspond to E1+2 primary oil generation stage, E1+2-E3 1 peak oil generation stage and E3 2 peak oil generation stage of source rocks, respectively. Finally, according to the process and history analysis of hydrocarbon accumulation, this paper presents the corresponding reservoir formation models in this area. References | Related Articles | Metrics

Origin of Heavy Oils in Xinlicun Oilfield, Dongying Sag LIU Hua, JIANG You-lu, GONG Yong-jie, ZHOU Yan 2008, 29 (2):  179-181.  Abstract ( 138 )   PDF (614KB) ( 189 )   Save Xinlicun oilfield located in eastern Dongying sag is characterized by normal crude associated with heavy oil which occurs mostly in structural high far from oil source. The analyses from fluid property, crude composition and geochemistry show that the heavy oil reservoir is in good condition of preservation in late period, slight microbial degradation, featuring low-maturity oils in half salt-saltwater lacustrine source rocks. The original heavy oil is resulted from low maturity and long distance migration, which reduces the lateral seal to faults and is favorable for forming reservoir. Moreover, as a kind of plugging zone, the heavy oil in this area plays an important plugging role in successively hydrocarbon accumulation. References | Related Articles | Metrics

Estimation of Oil Cracked Gas Resources in Tarim Basin HE Xun-yun, WANG Zhao-ming, HE Xiao-su, YANG Wen-jing, YANG Lan-ying, XIAO Zhong-yao, HU Jian-feng 2008, 29 (2):  182-186.  Abstract ( 93 )   PDF (817KB) ( 176 )   Save On the basis of previous studies, this paper presents the inverse estimation of oil cracked gas resourcesaccounting for 40%～ 52% of the total natural gas resources in ancient cratonic area in Tarim basin, and the forward estimation of it accounting for 49% of the total, according to theories of petroleum generation, migration and accumulation as well as petroleum system. The results show that Tarim basin is rich in oil cracked gas resources, mostly distributing in Tadong (eastern Tarim)area and Maigaiti slope, partly in Tabei (northern Tarim)and Tazhong (centre Tarim)areas. References | Related Articles | Metrics

Development of 3D Structural Model for Folded Basement in Junggar Basin ZHANG Ning, QU Guo-sheng 2008, 29 (2):  187-190.  Abstract ( 79 )   PDF (700KB) ( 207 )   Save The studied progress on basement property of Junggar basin is briefly introduced. Based on available information about various terrains, structures and deep geophysical explorations, with geographic information software (GIS)and GOCAD 3D modeling software, the translayer phenomena existed in geo-structural data in Junggar basin are corrected, and the sequence-structure model is developed. Moreover, according to the contact relationship between the folded basement and the cap rocks in the basin, the primary model for the folded basement is given, and constrained and corrected using the deep geophysical prospecting data, followed by providing a recent and valuable folded basement model for study of the cap rocks and basement structures in Junggar basin. References | Related Articles | Metrics

Char acteristics of Huoerguosi-Manasi-Tugulu Structural Belt in Junggar Basin PENG Tian-ling, YAN Gui-hua, CHEN Wei, XIAO Li-xin 2008, 29 (2):  191-194.  Abstract ( 122 )   PDF (1534KB) ( 295 )   Save Huoerguosi, Manasi and Tugulu anticlines belong to the second row of structures in piedmont thrust-fold belts in Junggar basin. By means of balance cross-section construction and fault-fold theory, 2D structural modes for these three anticlines are developed. The interpretation and correlation among them in old-new and 3D seismic profiles show that such a row structure is a superimposed combination shaped by early fold and late thrust breakthrough as well as mid-deep structures. References | Related Articles | Metrics

Analysis of Subsidence History of Zhusan Depression in Western Pearl River Mouth Basin LV Xue-ju, XIAO Li, LIN Zheng-liang, YUE Yong 2008, 29 (2):  195-197.  Abstract ( 107 )   PDF (863KB) ( 320 )   Save The back-stripping analysis of Tertiary subsidence history in Zhusan depression shows that its subsidence feature is closely related to the structural evolution and depression sedimentation of Pearl River Mouth basin. In the early Oligocene, the subsidence of Zhusan depression was mainly controlled by tectonic movement with big value of subsidence rate and rift filled by the lake, being in stage of fault and source rock development. In the late Oligocene, the depression entered into stage of fault and depression, controlled by tectonic movement and subsidence after rift, slowing the subsidence rate, shaping regional reservoir body with multi-set sand-shale sediments. By the end of Oligocene, the subsidence rate was increased, forming better regional muddy cap rocks in this area. References | Related Articles | Metrics

Geochemistry of Biogas Source Rocks of Neogene in Baoshan Basin LIU Si-bing, SHEN Zhong-min, LUO Xiao-ping, CHEN Yi-cai 2008, 29 (2):  198-201.  Abstract ( 86 )   PDF (401KB) ( 178 )   Save The analyses of organic carbon content, soluble organic matter, group composition, vitrinite reflectance and rock pyrolysis parameter from gas source rocks in Baoshan basin show that most samples have reached to criterion of oil generating rock on the stage of immature. The chromatographic analysis of saturated hydrocarbon indicates the weak oxidation/weak reduction environment appeared in stage of organic matter deposition, supplied dominantly by higher plants. The soluble organic carbon isotope study suggests that the organic parent materials in Well Baocan-1 are dominated by high plants with swamp facies in sedimentary environment. References | Related Articles | Metrics

Evaluation of Source Rocks of Well Shaxin-1 in Southwestern Margin of Qaidam Basin QING Ying, LUO Jin-hai, ZHANG Jing-yi, LIU Gui-hua, GAO Xue-feng 2008, 29 (2):  202-205.  Abstract ( 102 )   PDF (714KB) ( 213 )   Save The study on the comprehensive evaluation about the abundance of organic matter, type and maturity in dark mudstone of Paleogene and Neogene, ddrilled in Well Shaxin-1 on the structural belt of Shizigou-Youshashan in west deression of Qaidam basin and the oil-source correlation in the major layer of E3x and N1s of this well with its adjacent wells show that main part of the dark mudstone in Well Shaxin-1 is medium source rocks with organic matter of Type Ⅱ1 and Ⅱ2 . The source rock of N2 2s is in stage of low maturity, while those of N1s-E3x have entered mature stage. The correlation of oil sources indicates that the oil source from Well Block Shaxin-1 differs from adjacent wells areas and it assumes self-generating and self-storage type, which constraints the scale of hydrocarbon accumulation in some extent in Well Block Shaxin-1. References | Related Articles | Metrics

Fuzzy Comprehensive Appraisement of Selected Areas for Coalbed Mathane in Eastern Sag of Liaohe Basin ZHAO Zhong-ying, WANG Yu-lin, SUN Xiang 2008, 29 (2):  206-208.  Abstract ( 83 )   PDF (192KB) ( 222 )   Save Liaohe basin is one of domestic basins with coal, oil and gas resources. Its eastern sag contains coal bed that has characteristics of wide distribution, big thickness, low metamorphic grade and deep buried depth. It is significant to appraise the selected areas of coalbed methane in this sag for optimizing the exploratory areas and developing the conventional oil-gas and non-conventional coalbed methane resources. This paper chooses the coalbed cumulative thickness, gas content, gas saturation, reserves abundance of coalbed methane, coalbed continuity and cap rock condition as factors for assessment to develop a fuzzy comprehensive appraisement model adaptable to the studied area. The assessment result indicates that Rehetai-Sanjiepao area and Oulituozi area in the eastern sag are more favorable, the former is of big thickness, good continuity and shallow buried depth of coal bed, being as the most favorable area for coalbed methane exploration in this sag. References | Related Articles | Metrics

Controls of Tan-Lu Fault on Paleogene Depositional System in Qingdong Sag LI Chun-rong, XIN Ren-chen, LI Jian-ping, LIU Hao 2008, 29 (2):  209-213.  Abstract ( 103 )   PDF (1147KB) ( 261 )   Save Qingdong sag was shaped in Paleogene companied by Tan-Lu fault activity. So the structural activity, specially syndepositional faults and their combination patterns controlled the development and distribution of stratigraphic and depositional systems. Continuing activity of F and F1 fault zones in the Paleogene controlled depositional filling of the northern deep sub-sag, while F2 and F4 fault zones separately controlled development of middle and southern secondary sub-sags. The slope break zone of fault formed by long-term activity of syndepositional faults constituted the boundary of depositional systems and controlled the distribution of Paleogene sedimentary facies. The slope break zone of fault formed by the eastern basin marginal fault controlled development of coarse-clastic depositional systems, such as sublacustrine fan, fan delta and braided delta. The syndepositional faults of F1, F2, F3 and F4 are generally boundaries between sedimentary facies. The slope break zone of faults formed by main syndepositional fault adjacent to oil generating depression has favorable conditions for formation of sandstone reservoirs, and the eastern basin marginal fault zone and F1 fault gentle-slope zone of northern subswell are favorable sites of looking for potential sandstone reservoirs. References | Related Articles | Metrics

Geochemical Characteristics of Dolomite Oil Seepage in Zar ing Ar ea,Qiangtang Basin of Tibet CHEN Wen-bin, LIAO Zhong-li, LIU Jian-qing, FU Xiu-gen, XIONG Xing-guo, HE Yong-zhong 2008, 29 (2):  214-218.  Abstract ( 89 )   PDF (1057KB) ( 205 )   Save The oil seepages from oil-bearing dolomite in Zaring area of Qiangtang basin are high fraction of saturated hydrocarbons (5.4% ~68.2%)without asphaltene. The geochemical characteristics of oil seepages are analyzed by group component, carbon isotope and biomarker, etc. The results show that they have low values of m (Pr)/m (Ph)by 0.60~0.98, carbon isotope values ranging from -26.88‰ to -31.09‰, not high maturity of the oils, belonging to reductive environment and dominated by microbe and algae parent materials. The relative content index of free hydrocarbon carbon isotope and biomarker and the oil source correlation indicate that the oil seepages were formed by the same source rock and origin. The Xiali source rock of Middle Jurassic in Zaring area could be main source of the oils. References | Related Articles | Metrics

Identification and Origin of Low-Resistivity Oil-Gas Layers in Junggar Basin XIE Hong-wei, HU Ping, WANG Jian-fu, HU Ping-ying 2008, 29 (2):  219-221.  Abstract ( 144 )   PDF (88KB) ( 260 )   Save Low-resistivity layer (reservoir)in Junggar basin features multi-origin, wide distribution and difficult identification. This paper discusses its origin and presents the identifying method. Study shows that low-resistivity layer is characterized by low resistivity, sand-mud interbedding, developed micropore and weak drill show, with montmorillonite and illite-smectite interstratified minerals. And additional conduction, high salinity, high irreducible water saturation and drilling mud invasion, etc. are the key factors for forming low-resistivity layer (reservoir). Well log and logging, etc. are the main identifying techniques for it. References | Related Articles | Metrics

Well Test Interpr etation Model and Pressure Response for Triple Porosity Media Reservoir ZHANG De-zhi, YAO Jun, WANG Zi-sheng, ZHAN Ai-ting 2008, 29 (2):  222-226.  Abstract ( 76 )   PDF (681KB) ( 242 )   Save This paper presents the model for well test interpretation of triple porosity media reservoir composed of matrix, fracture and vug, in which wellbore storage and skin effect are considered by fully implicit difference format, and related numerical solutions are given. The comparisons of this model with models for vug to wellbore connection and fracture-vug to wellbore connection are made in pressure response, including analyses of interporosity flow coefficient, storativity ratio, permeability ratio and the effect of outer boundaries on pressure response. The results show that this mode contains these two connection models, where interporosity flow coefficients (λfv and λmv)are used to determine the time of transition interval emergence; storativity ratio (ωv and ωf)to affect the depth and width of sag-like curves of pressure derivative, permeability ratio (K0 v)to influence the shape of interporosity flow transition curve, and sealed boundary and isopressure boundary to result in late curve "up" and "down" in pressure derivative. References | Related Articles | Metrics

Discussion on Theoretical Derivation and Application of Wang-Li Model for Production For ecast LI Fa-yin 2008, 29 (2):  227-228.  Abstract ( 98 )   PDF (63KB) ( 241 )   Save Some doubts about Wang-Li model for production forecast are currently proposed by genuine scholars. This paper presents the theoretical re-derivation and the applied analysis, and suggests that some misunderstandings truly exist in this model. A few easily confused problems in it are fully clarified, providing a valuable support for its proper field application and generalization. References | Related Articles | Metrics

Status and Under standings of Gas Slippage Effect Studies on Low-Permeability Gas Reservoir WAN Jun-feng, LU Yuan, ZHAO Shi-jun 2008, 29 (2):  229-231.  Abstract ( 76 )   PDF (294KB) ( 248 )   Save As an important factor affecting low speed percolation law, gas slippage effect has been paid attention to. Many scholars studied the factors of affecting slippage effect and the permeability parameter measurement affected by slippage effect, but differences were still obvious in their studied conclusions. This paper summarizes the research efforts focused on the gas slippage effect at home and abroad and points out existing problems. This could be significant to low speed percolation research and proper determination of relative permeability for development of low permeability gas field. References | Related Articles | Metrics

Cutoff Permeability for Low Permeability Reservoir by Water flooding Process HUANG Xiao-liang, TANG Hai, SHI Zi-li, LV Dong-liang, ZENG Jian, LIAO Hua-wei, CHEN Jun-yu 2008, 29 (2):  232-234.  Abstract ( 84 )   PDF (501KB) ( 175 )   Save Based on stable flow velocity model with equal production one source and one gathering and analysis of maximum pressure gradient field, relationship between starting pressure gradient and injection-production differential pressure and producer-injector spacing is presented. And using starting pressure gradient vs reservoir permeability, the cutoff permeability suitable for effective waterflooding of reservoir under different injection-production conditions is given. The theoretical and practical results are generally identical, indicating its good practicability, which can be as a guide for effective development of low permeability oilfield. References | Related Articles | Metrics

A New Method for Testing Analysis of Gas Well Production at Constant Pressure LUO Yin-fu, MA Zhong-liang, XIE Jian-fei, LONG Zhong-feng, YI Xia 2008, 29 (2):  235-237.  Abstract ( 97 )   PDF (258KB) ( 202 )   Save As for constant-pressure gas production, the conventional semi-log plot of the inverse of the dimensionless rate versus the dimensionless time must be modified to account for high-velocity flow effects. Especially when reservoir permeability is higher than 1 mD, the well test is affected by non-Darcy flow and formation damage. This paper presents a new gas well testing analysis method considering gas well producing at constant pressure in infinite gas reservoir accounting for high velocity non-Darcy flow effects in vicinity of the well bore. This method is simple and direct and doesn't need type-curve matching or data regression. Case study shows that single constant pressure test can allow to precisely determine permeability, non-Darcy flow factor and skin factor of gas reservoir in gas well that constant-pressure well testing can be applied. References | Related Articles | Metrics

Calculation of Irregular Polygon Area of oil-Gas Reservoir Using Microsoft Excel Software WEI Zhong-yuan, GUO Zhen-hua, WANG Hai-ying 2008, 29 (2):  240-243.  Abstract ( 110 )   PDF (212KB) ( 234 )   Save Traditional method for calculation of irregular polygon area of oil-gas reservoir is very complicated and makes mistakes easily because of plenty of work and low accuracy. This article introduces the principle of calculating acreage of irregular polygon, then analyzes the algorithm of irregular polygon area acquisition using macro function in Microsoft Excel, and finally lists some key step codes in the program. The author uses the program to calculate acreage of oil/gas-bearing area, greatly improving working efficiency. References | Related Articles | Metrics

New Method for Productivity Prediction of Heavy Oil Reservoir in Junggar Basin ZHAO Rui, ZOU Zheng-yin, SUN Xin-ge, HAN Hai-ying, CHEN Xue-xing, WANG Hai-ming 2008, 29 (2):  244-246.  Abstract ( 89 )   PDF (140KB) ( 265 )   Save The grey degree of relevance analysis between main reservoir geologic parameters such as crude viscosity, net pay thickness, porosity, permeability, oil saturation, reservoir depth and steam injection volume and productivities from twenty one blocks in northwestern margin of Xinjiang oilfield shows a good relationship between them by the fact that a closed relationship between these parameters and conductivity or deliverability. The regression analysis also shows that complex nonlinear relationships occur between them. With Cobd-Douglas equation, this paper presents the successful match of it and develops the deliverability equation based on reservoir geologic parameter for direct prediction of heavy oil productivity. Moreover, three heavy oil blocks in Karamay oil field are forecasted using this equation and the results indicate that this method is feasible. References | Related Articles | Metrics

Application of Imbibition Curves to Production Forecast in Fractur ed Reservoir YUAN Ying-zhong, ZHANG Lie-hui, SUN Zhi-xue, WANG Jian 2008, 29 (2):  247-249.  Abstract ( 74 )   PDF (244KB) ( 222 )   Save Imbibition is an important mechanism of water-oil displacement in fractured reservoir, so the production from fractured reservoir reflects the characteristics of imbibition. When the production comes into decline stage, the decline regulation is generally complex. Big errors exist in history match and future prediction with conventional methods. Based on the imbibition curve of Aranofsky, a new model for production forecast in fractured reservoir is proposed using the imbibition equation given by Kewen Li, et al. Applied to H2 oil layer in Huoshaoshan oilfield, the result shows that this method is applicable for production forecast of fractured reservoir. References | Related Articles | Metrics

Principal Direction Differential Strain Method for In-Situ Stress Measurement and Application SHEN Hai-chao, CHENG Yuan-fang, WANG Jing-yin, ZHAO Yi-zhong, ZHANG Jian-guo 2008, 29 (2):  250-252.  Abstract ( 102 )   PDF (367KB) ( 424 )   Save Big difficulty normally appears in lab terrestrial stress measurement by conventional differential strain method. This paper firstly introduces the theory about anisotropy of core wave velocity vs. in-situ stress direction into differential strain analysis (DSA), and proposes a new simple and practicable method for lab in-situ stress measurement-principal direction differential strain analysis (PDDSA). The principle of this method is using anisotropy of core wave velocity to measure horizontal principal stress by which prepares samples for DSA experiment. The results by PDDSA are consistent with relatively high-accuracy hydraulic fracturing measures, indicating that PDDSA is better than DSA in accuracy, lab experimental difficulty and work requirement. References | Related Articles | Metrics

Application of Digital Image Processing to Determination of Petrophysical Property LI Bing, LING Qi-cong, BAO Zheng-yu, XIE Shu-yun 2008, 29 (2):  253-255.  Abstract ( 82 )   PDF (307KB) ( 308 )   Save Fractal or multi-fractal as one of complexity sciences has been applied into various fields of geoscience such as element concentration, ore-deposit reserves and rock porosity distribution, etc. with good results. A lot of attention has been paid to the study of micro-structures of carbonate rocks in recent years as it has been recognized extensively that traditional analysis methods are fault and not enough to depict the complexity of them. Lots of samples from outcrops in different lithological strata in Dasan member, Chang'er member and Jiasan member are selected in Xiakou and Shizhu cross sections in western Hubei province to study their micro-structures and acquire the statistical parameters like porosity, permeability and shape, etc. By comparing with the measured physical data, it could draw a conclusion that this method is feasible and superior to conventional experiment method. References | Related Articles | Metrics

Mesozoic Paleo-Uplift Not Occurred in Center of Junggar Basin LIU Chao-rong 2008, 29 (2):  256-259.  Abstract ( 92 )   PDF (617KB) ( 227 )   Save Since the Middle-Upper Jurassic in Sangequan-Mosuowan-Shamenzi belt in center of Junggar basin is almost missing, people had been thinking that it was a "paleo-uplift" caused by erosion. This paper argues that such an idea contradicts with the real conditions, for uplift shape and erosion or denudation are not found in available information, which is also in inconsistency to the sedimentary feature of overlying Cretaceous and the sedimentary facies in this area. In contrast, the correlation results based on drilling data indicate that in Middle and Late Jurassic there exists a high water-level stage or water-invaded stage during evolution process. And in the incomplete strata caused by insufficient filling not appear uplift and erosion, the "paleo-uplift" does not occur in the center of Junggar basin. References | Related Articles | Metrics

Application of NMR Log Data to Formation Pore Structure Evaluation XIAO Liang 2008, 29 (2):  260-263.  Abstract ( 102 )   PDF (279KB) ( 253 )   Save The principle of evaluation of formation pore structure with NMR logs is presented. The effect of hydrocarbon-bearing reservoir on distribution shape of t2 in NMR logs is discussed. It is suggested that its applied conditions and suitable scope should be paid attention to. In some conditions, such a distribution shape of t2 in NMR logs should be corrected into that in state of 100% water saturation, followed by using the method of percentage of three-porosity composition to evaluate the formation pore structure, the results will be more reasonable. References | Related Articles | Metrics

A Discussion of Units and Symbols in Reservoir Engineering LI Chuan-liang 2008, 29 (2):  264-267.  Abstract ( 144 )   PDF (268KB) ( 462 )   Save A study is conducted on the units and symbols used in reservoir engineering. The advantage of SI for reservoir engineering is discussed, including improvements for them as required. Some units and symbols in new standard, The Common Units and Symbols for Oil-Gas Exploration and Development (No.SY/T6580-2004), are discussed, which is helpful to proper use of these units and symbols available. References | Related Articles | Metrics