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01 April 2002, Volume 23 Issue 2 Previous Issue    Next Issue

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Late Adjustment and Re-Accumulation as a Major Feature of Marine Petroleum Accumulation in Tarim Basin ZHAO Jing-zhou, LI Xiu-rong 2002, 23 (2):  89-91.  Abstract ( 126 )   PDF (457KB) ( 226 )   Save The marine hydrocarbon accumulation in Tarim basin is characterized by multi-period accumulations and late adjustment. The late adjustment and re-accumulation is an important type of its petroleum accumulation; secondary reservoirs formed by adjustment of late accumulation is a significant style of it; and Himalayan (Cenozoic) and top of paleo-uplift are the major period and area of adjustment and re- accumulation respectively. The discovered Himalayan oil reservoirs are mostly secondary ones formed in such a way of late Hercynian reservoir re-accumulation,which mainly distribute in Mesozoic reservoir of Lunnan uplift and Carboniferous reservoir of the Central Tarim uplift. Therefore,to search for large- and medium-scale marine primary hydrocarbon reservoirs should highlight the relatively stable and inherited paleo-uplifts and paleo-slopes, whereas the uplift highs are the major areas for formation of secondary reservoirs. References | Related Articles | Metrics

Exploration Potential in Santanghu Basin WANG Chang-gui, YANG Biao 2002, 23 (2):  92-94.  Abstract ( 98 )   PDF (527KB) ( 332 )   Save Tiaohu sag and Malang sag are primary source depressions in Santanghu basin. They are depressions with above medium abundance in petroleum resources. This study showed that a little too high appeared for their estimated value of resources for reasons of insufficient understanding of source- rock-richness in them; the cap rock and carrier rock in the basin are not large in size, so it is not favorable to long-distance hydrocarbon migration. Also, study of the organic matter inclusion enclave showed that hydrodynamic conditions for petroleum migration are relatively poor, dominated by short-distance vertical migration, and only reservoirs with both source and seal are formed. The computed value showed that the source potential index in Santanghu basin is lower, possibly providing medium- and small-sized reserves. Therefore, the target zone should be explored dominantly in Upper Permian Lucaogou formation, and paying attention to its piedmont and foothill overthrust belts for exploration. At present, to understand the piedmont geologic structures is very difficult because the seismic data are insufficient and there exist some problems in interpretations. References | Related Articles | Metrics

Achievements from Petroleum Exploration in Central Tarim Area and Its Further Exploratory Directions WU Mao-bing, WANG Xin-min, CHEN Qi-lin, YANG Zhan-long 2002, 23 (2):  95-97.  Abstract ( 76 )   PDF (424KB) ( 227 )   Save This paper outlined the exploratory achievements in central Tarim area, discussed its resource potentials in north slope structural belt and central fault horst zone,analyzed five causes for failure of drilling, in which the major cause is indeterminate structures for drilling resulted from static corrections and average velocity field problems. It is pointed out that the exploration of central Tarim area should focus on No.1 fault belt in lower structural layer and that of low amplitude in middle structural layer. In addition, evaluation in trap types of low amplitude anticlinal trap in Donghe sandlayer of Carbonifeous and stratigraphic-lithologic trap of Ordovician should be paid attention to,improving ability of prediction of effective carbonate reservoir; in light of effect of igneous rock on hydrocarbon reservoir and developed characteristics of Ordovician “domal abnormal body” search for new domains for petroleum exploration. References | Related Articles | Metrics

Destructive Mechanism of Gas Accumulation and Its Assessment of Preservative Conditions LUO Qun, BAI Xin-hua 2002, 23 (2):  98-101.  Abstract ( 101 )   PDF (618KB) ( 213 )   Save The easy destructive and difficult preservative properties tend to take a great risk for gas prospecting. Tectonic movement, hydraulic scouring and micro leakage become three important mechanics in destruction of a gas accumulation, of which denudation and rupture in cap rock arisen by tectonic movement could be the most serious to its destruction. The serious destruction of deep gas accumulation in Yingshan fault depression is mainly resulted from the fault movement. The primary reason for its destruction is that dispersion lost velocity is greater than that of gas source. supply into gas pool. This paper presented a model for assessment of destructive element, destructive intensity and preservative conditions of a gas accumulation. And the evaluation of the destructive element of major target zone in deep gas accumulation of Yingshan fault depression was made by using this model. References | Related Articles | Metrics

Geologic Features of Ordovician Oil Control in Akekule Arch MAO Qian-ru, JIANG Hua-shan, YAN Wen-xin 2002, 23 (2):  102-105.  Abstract ( 85 )   PDF (855KB) ( 184 )   Save Akekule arch is located in south side of middle part of Shaya uplift in Tarim basin, in which Ordovician carbonate rocks have a broad prospect for petroleum exploration. However, it is obviously controlled by regional structural setting and reservoir development hence resulted in non-homogeneous oil and gas distribution. Based on analyses of the types, distribution and oil-controlled geologic features and predictions of the effective scale of Ordovician petroleum reservoir, it is considered that some effective reservoirs are developed and reserved in karst, buried hill and serious deformation zone of slope area of southern A kekule arch, and there exist multistage petroleum migration, accumulation and forming reservoirs with fair seal conditions,which might be a favorable area for forming a large-scale oil and gas pool. References | Related Articles | Metrics

Geological Characteristics and Prospect Evaluation on Coal-Seam Gas in East Yunnan and West Guizhou Areas GU Cheng-liang 2002, 23 (2):  106-110.  Abstract ( 156 )   PDF (1248KB) ( 253 )   Save The major coal-bearing strata of Permian in East Yunnan and West Guizhou areas are Longtan formation of Upper Permian,which distributed in some coal-accumulated basins with complex anticline and syncline structures. The coal measures are well developed in this area with an area of coal-bearing strata of 2.58×104km2,and dark metamorphism and thermal magma metamorphism. The coal evolution is in stage of maturity to over-maturity. The gas reserve is tremendous (13 078×108m3) with good seal condition, gas generating capacity and good reservoir. The amount of coal-seam gas is mainly controlled by the depositional environment, coal evolution degree, burial depth, hydrologic condition and structural conditions. The gas reserve capacity is the essential factor controlling the gas-bearing amount in coal measures,which increases with the growth of coal ranks and burial depths ( the most distinct example is when the burial depth is less than 800 m). The gas bearing amount in coal beds is 10.0~18.8m3/t. For low-rank coal, the gas reserve capacity of fusinite coal beds is higher than that of vitrinite, while it is contrary for high-rank coal. For high vitrinite content, the coal beds have higher adsorption capacity and optimistic prospects for evaluation of this area. References | Related Articles | Metrics

A Discussion on Paleogene Jiyang Depression Characteritics and Its F orming Mechanism WU Fu-qiang, WANG Xiao-kun, HU Xue, LIU Jia-duo 2002, 23 (2):  114-116.  Abstract ( 93 )   PDF (416KB) ( 269 )   Save According to the structural and sedimentary evolution, Jiy ang depression is a compound and superimposed basin with complex evolutionary history that there existed different basins of primary types and different sedimentary assemblages. It is confirmed that Jiyang depression of Paleogene occurred in trans-extensional behavior in the light of Moho uplifting, lithosphere thinning, development of basic and ultra basic igneous rocks in mantle source rocks, high geothermal gradient,halfgraben-like depression basin groups, extensional amount of more than 50km and sedimentary velocity up to 0.1mm/a, well-developed tensional fractures, lithosphere appearing sandwich-like rheological structure, seismic source mainly taking place in the middle crust and release of mantle source gases as well as property of Tanlu fault. The mechanism of trans-extensional basin is discussed. References | Related Articles | Metrics

Theoretical Effect of Electromagnetic Field Continuation Imaging on Multiple and Proximity Rejection HOU De-jin, HUANG Jun-ming 2002, 23 (2):  117-120.  Abstract ( 78 )   PDF (274KB) ( 290 )   Save Similar with seismic prospecting, there exist multiple and proximity disturbances in magneto-electrotelluric exploration(MTE). To study this problem is an important in geologic interpretation of MTE data. Theoretically, this study analyzed existence of multiple wave in pseudo seismic interpretation of MT,pointed out that no multiple interference appears in the magneto-electrotelluric sounding reflectance functions, and derived mathematical relations between the reflectance function and top proximity interference, giving the way of frequency-selecting for rejection of top proximity interference. Finally, the theoretical model was estimated by using pseudo seismic interpretation of MT and electromagnetic reflectance function continuation imaging methods for indicating effect of the theory. References | Related Articles | Metrics

Hydrocarbon Generating History in North Slope of South-west Depression in Tarim Basin to Bachu Arch LIU Chang-wei, WANG Fei-yu, LI Shu-yuan 2002, 23 (2):  121-123.  Abstract ( 65 )   PDF (797KB) ( 221 )   Save The vitrinite reflectance of 29 source rock samples selected from three strata-Carboniferous, Middle-Upper Ordocician and Middle-Lower Cambrian in 9 wild wells of the study area were measured, layering data of 40 artificial boreholes were obtained by using 3 seismic profiles, and analysis of hydrocarbon generating history in the source rock was made in detail integrated with data of stratigraphic denudation thickness and geothermal gradient available. Study shows that the source rock in north slope of southwest depression in Tarim experienced fast burial with hydrocarbon generating, quick growth of organic maturity associated with tremendous gas generation in Neogene. In contrast, the source rock in Bachu arch was subjected to and ended up with early evolution and no hydrocarbon generation took place after 250Ma. In its largest gas accumulation, Hetian river gas field, the carbon isotope of ethane (δ 13C2) ranges from 37.8‰ to -34.9‰, indicating that the gas was generated from type- II kerogen, the natural gas maturity is within 1.67%~2.34% based on δ 13C1-R0 reduction formula. It is given that the source rock should be that of Middle-I ower Cambrian compared with its organic matter type and maturity (measured and simulated values). The study shows that natural gas from Hetian river gas field was mostly generated by the way that north slope of southwest depression in Tarim was fast buried by Tertiary strata hence resulted in thermal pyrolysis of kerogen in Middle-Lower Cambrian source rocks and migrated all the way into the joint area between the north slope and Bachu arch. References | Related Articles | Metrics

Karstification of Carbonate Reservoir in Hetian River Gas Field of Tarim Basin YANG Wei, WANG Qin-hua, ZHAO Ren-de, LIU Xiao-zeng 2002, 23 (2):  124-126.  Abstract ( 90 )   PDF (360KB) ( 291 )   Save Hetian river gas field, a large-scale carbonate gas pool recently found or proved in Tarim basin, is well-developed in karstification for its major reservoirs such as Ordovician buried hill limestone and Carboniferous bioclastic limestone. Based on the time, location and mechanism of each type of karsts, the primarily developed karstifications include interlayer karst and weathering crust karst formed by atmospheric fresh water process as well as buried karst, of which Ordovician buried hill karst was formed by organic acid action,while Carboniferous bioclastic limestone buried karst by sulfidation dissolution. The karstification is mainly controlled by lithology, structure, palaeogeomorphology and palaeoclimate, and it could improve porosity and permeability in the carbonate reservoir. References | Related Articles | Metrics

Analysis of Interfacial Structure in J1s22 Internal Sequence of Jurassic Sangonghe Formation in Junggar Basin LIU Hao, WANG Ying-min, WANG Yuan, JIN Wu-di 2002, 23 (2):  127-129.  Abstract ( 78 )   PDF (166KB) ( 223 )   Save The research of outcrop,drilling, well log and seismic data showed that in J1s22 sand body of Jurassic Sangonghe formation in Junggar basin, a Jurassic interior sequence interface that defined as J1S3 was developed on anti-cycle’s turning point, with obvious recognition mark and fair responses in outcrop, drilling, well log and seismic profile. Because of bigger differences of assemblage relations of J1s22 sand body in different parts of the basin,extreme differences occurred in the interfacial configuration,mainly showing the characteristics of complicated contact relations between upper and lower lithologic properties in bottom of the sequence, varied geophysical parameters along its strata as well as bigger differences in upper and lower seismic interface reflection structures. The important controlled factor of forming non-homogeneity of this interface within the whole basin could be the fact that differentials of structural movement, particularly, those of local structural movements in the whole basin, which lead to variation of containable spaces in the different areas. Also, deposit supply and climatic variation or fluctuation is one of primary affective factors. References | Related Articles | Metrics

Characteristics of Sedimentary Evolution in Yanqi Mesozoic Prototype Basin LIU Xin-yue, LI Yong-lin, HE Min-xi, TIAN Na-xin, NAN Hong-li, CHEN Gang 2002, 23 (2):  130-133.  Abstract ( 90 )   PDF (1054KB) ( 279 )   Save This paper discussed the characteristics of palaeoclimate variation, paleotopography evolution, paleodeposit boundary change, rise and fall and deposition of lacustrine deposit datum level,,migration of subsiding center and sedimentary system evolution in Yanqi Mesozoic prototype basin. Since the lacustrine deposit datum level occurred twice rising in Middle-Late Triassic and late of Early Jurassic, three sedimentary cycles, i.e. Middle-I ate Triassic, early of Early-Middle Jurassic and late of Middle Jurassic-early of Late Jurassic, were formed in the basin. During Triassic to early of Middle Jurassic, a sedimentary system composed of alluvial apron or stream (humid fan)-braided stream-meandering stream-shallow shore lake appeared from margin to center of basin; while in the mid epoch of Middle Jurassic stream sedimentary system occurred. References | Related Articles | Metrics

Studies of Exploitation Technologies of “Megascopic Scale” Unswept Remaining Oil in a Waterflooding Sandstone Reservoir YU Qi-tai 2002, 23 (2):  134-138.  Abstract ( 94 )   PDF (704KB) ( 325 )   Save The research strategy being divided into three-step runs for EOR is proposed. The first step is the study of distribution type and exploitation technology of “megascopic scale” unswept remaining oil;; the second step is the study of distribution type and exploitation technology of “macroscopic scale” unswept remaining oil;; the third step is, on the basis of these two steps,to study the way of improving oil displacement efficiency in swept areas. Ten technologies for developing three enriched areas of “Megascopic scale” unswept remaining oil are presented. They are:①technologies for producing the unswept remaining oil at the top of the positive rhythm reservoirs with high viscous oil,, including horizontal sidetracks, cyclic waterflooding, water/ gas alternation, gel/ propellant/ acid-fracturing treatment;; ②)technologies for producing the unswept remaining oil caused by side and corner parts in oil reservoirs, including reversed and vertical fracture fracturing with reversed direction and orientation, horizontal sidetracks, horizontal well; ③technologies for producing the unswept remaining oil formed by non-proportional development of each substratum with different petrophysical properties, including dewnhole measures (water shutoff, profile control, and stimulation of low permeability, etc.), infill well and changing direction of filtration flow. References | Related Articles | Metrics

Computation for Infill Well Spacing Density in Old Fields LIU Yan-ming, DONG Guang-hua, QIAN Yu-xiang, LUO Zhi-xing, BAI He-xian 2002, 23 (2):  139-141.  Abstract ( 105 )   PDF (300KB) ( 237 )   Save This study takes old oilfields of PetroChina Xinjiang Oil as examples, begins with Cierkaqov’s equation, relates to analysis of economic appraisal stage, gives computations for well spacing density at economical limit and optimal economic spacing density of an old oilfield. This method is practical implications for infill development of old fields, particularly to sporadic infill drilling of old fields with high water cut. This method allows decision maker to avoid risk from exploitation investment in a great extent. References | Related Articles | Metrics

Computations for Benefit Output in an Old Oilfield LIU Bin, GUO Fu-jun, XU Yan, YANG Li, WANG Ya-xian 2002, 23 (2):  142-143.  Abstract ( 76 )   PDF (133KB) ( 281 )   Save Because there is no methods for systematic evaluation of benefit output available to date, it is difficult to quantitatively describe benefit from an old oilfield. This study developed a model and presented a method for estimating the benefit output, in light of productive regularity of an old oilfield and incoming time-cost function,integrated with production indexes and economic factors. It is indicated that the method is relatively comprehensive, the equations are practically identified by field data. Hence, it is of importance for related departments to evaluate the economic benefit of an old oil field. References | Related Articles | Metrics

Study on Methods for History Match of Conglomerate Reservoir —an example of Lower Karamay reservoir in West District 5-(2) CHEN Qiang, CHEN Ru-he, HUANG Qing-min, HU Xin-ping, ZHEN Qiang, DING Yi 2002, 23 (2):  144-145.  Abstract ( 73 )   PDF (410KB) ( 201 )   Save Abstract:The water-intake of non-reservoir sandbody in conglomerate reservoir tends to give high simulated pressure. This paper solved such problems and estimated the amount of water-intake in non pay zone using technologies of reservoir numerical simulation and setting virtual strata and virtual wells. Based on the results of production history match of district-wide and individual well, geological model and production performance model were corrected, further howing heterogeneity of the reservoir. Recommended adjusting programs are highly fitted to the field situation and good results are obtained. References | Related Articles | Metrics

On the Effect of Different Fractural Distribution on W ater-Oil Displacement LIU Jian-jun, LIU Xian-gui 2002, 23 (2):  146-147.  Abstract ( 79 )   PDF (415KB) ( 214 )   Save The water-oil displacement procedures of 6 types of different fractural distributions were physically modeled using slice models,obtaining the patterns of water-oil displacement in different fractural geometric configurations compared with their analytical effects. It shows that the relation between fractural orientation and percolating direction is of the maximum influences in the displacement effects; the lengths of fractures and the configurations in length are in the second important effects on the water-oil displacement. References | Related Articles | Metrics

Study of Numerical Simulation of Rational Well Patterns for Development of Fractured Oilfield LI Xing-min, MA Xin-fang, LANG Zhao-xin 2002, 23 (2):  148-149.  Abstract ( 65 )   PDF (286KB) ( 200 )   Save The numerical simulation of proper well patterns for development of low permeability oilfield with mi crofractures was studied applying black-oil model to investigate the quantitative relationship between directional permeability ratio and proper well spacing versus well array, providing the optimum well pattern for different directional permeability ratio. Based on the optimum well pattern, determination of the optimum half-length of hydraulic fractures was analyzed during overall fracturing measures. References | Related Articles | Metrics

Study of Flow Element of Conglomerate Reservoir in Upper Karamay Formation, District 8 in Karamay Oilfield SONG Zi-qi, GAO Xin-jun, TAN Cheng-qian, WU Shao-bo, LIU Shun-sheng, QIN Jian-hua, DAI Can-xing, LUO Zhi-xing 2002, 23 (2):  150-153.  Abstract ( 90 )   PDF (514KB) ( 204 )   Save This paper analyzed the basic ideas and principle for flow element study in light of the characteristics of conglomerate reservoir in Upper Karamay formation of District 8, Karamay oilfield, studied ty pes and features of the flow element, delineation and computed methods of flowing zone index (IFZ), based on corresponding cluster analysis integrated with Upper Karamay reservoir lithology,petrophysical property and microscopic pore structural features, and classified and described the individual small flow element in this conglomerate reservoir. Furthermore, the distribution and characteristics of different ranking flow elements and their relations to depositional microfacies, barriers and interbeds as well as reservoir quality were analyzed and explained, providing the qualities of conglomerate reservoirs in different horizons and distributed or enriched areas. References | Related Articles | Metrics

Application of Value Appraisal Theory in Planning for Petroleum Exploration and Development ZHANG Yu, ZHANG Zhi-ying, YUAN Xin-xi, LI Yong-xi, WANG Xiang-dong 2002, 23 (2):  154-157.  Abstract ( 78 )   PDF (511KB) ( 238 )   Save The basic meaning and functions of value appraisal theory in enterprise are explained. Two techniques for developing a value appraisal model are proposed. The different and common points between value appraisal theory in enterprise and traditional project economic evaluation are pointed out. It is indicated that application of the theory into the petroleum exploration and development planning compilations can obtain good results. For the economic evaluation model focused with project appraisal is broken through using this method, accurate measurement of the effect of newly incremental benefits from a company's capital on initial benefit is performed macroscopically. Hence, it will serve positive actions for the optimizing and allocation of entire resources of an oil company. References | Related Articles | Metrics

Application of Improved Gauss Cut-Off Modeling Algorithm to Develop Phase Distribution Model HUANG Cang-dian 2002, 23 (2):  158-159.  Abstract ( 112 )   PDF (250KB) ( 252 )   Save This study presented in-depth analysis of Gauss cut-off modeling algorithm, a conventional phase modeling algorithm, in which new understanding of developing local pseudo gauss field was given, that is using phase vertical frequency curve to develop pseudo gauss field in Gauss cut-off modeling algorithm,hence correction of the limitations of it was made. And new flow of Gauss cut-off modeling was provided with an example of its application. References | Related Articles | Metrics

A Combination Prediction Method for Development Indices CHEN Zhi-gang, SHU Fu-chang, JIA Li, Zhen-Yan, LI Xian-jing 2002, 23 (2):  160-162.  Abstract ( 83 )   PDF (226KB) ( 287 )   Save The generalized Weng's model, dual logarithm production decline curve model and water drive curve model are popular to use in reservoir engineering study. However, they have their own limitations. Integrated with these methods, this paper presented a combination prediction method to correct predictive results as well as providing explanation in, detail of their solutions. This method is not only. applied. to predict production, water production, the, top annual yield and related time in a hydrocarbon field by waterdrive process, but also to predict recoverable reserves, water cut and volumetric sweep efficiency. The result shows that it has much higher predictive power and precision compared with other models. References | Related Articles | Metrics

Equations for Stress Relations in Porous Medium-in reply to Mr. Zhou Da-chen LI Chuan-liang 2002, 23 (2):  163-164.  Abstract ( 86 )   PDF (182KB) ( 265 )   Save There are certain relations among overburden pressure,underlying fluid pressure and matrix stress, and different understandings of how to describe or depict them in the end. This is an important question involving how to understand the basic concept of effective stress in porous medium mechanics. This study restated proper relations among these three stresses at any locations in porous medium, and called the corresponding mathematical expressions the stress-based equations of porous medium. References | Related Articles | Metrics

Effect of Tectonism on Hydrocarbon Generation, Migration and Accumulation YUAN Ming-sheng, HUANG Wei-dong, LI Hua-ming, WANG Zhi-yong 2002, 23 (2):  165-169.  Abstract ( 75 )   PDF (244KB) ( 274 )   Save At the beginning of burial, organic matter in natural world would have been in extremely complicated geophysical and geochemical fields where there existed two kinds of environmental energies: thermal energy and mechanical energy. The latter could be transferred into petroleum system by its mechanical stresses,and endued with a certain of mechanical energy in form of mechanical wave. Once a faulted fold structural movement took place,the mechanical stress had obvious effect on hydrocarbon migration, which might be converted or transformed into degradation of the energy and drive of ground stress, such a series of chain reactions would result in successive high efficient events in hydrocarbon generation,migration and accumulation. This study proposed a hypothesis that it is tectonic movement that creates events of hydrocarbon generation and drainage and accomplishes a petroleum system in light of saltatory evolution and by idea of transforming controlled formations. References | Related Articles | Metrics

Chaotic Theory and Its Application in Fluid Mechanics NING Zheng-fu, YAO Yue-dong, LI Guo-zhen, GE Jia-li 2002, 23 (2):  170-172.  Abstract ( 175 )   PDF (156KB) ( 923 )   Save This paper reviews the importance and advantages of chaotic theory applied in nonlinear science. The basic principle,research methods and the application in solving complex natural science of this theory are described. The application in fluid mechanics is highlighted. The possibility of using chaotic theory in complex system of oil and gas flow in porous media is analyzed, showing that taken the theory as a guide,the study of percolation mechanics will be deepened further. References | Related Articles | Metrics

A Prediction Method of the Petroliferous Property in Lower Cambrian and Vende System in Hinterland of West Siberian Platform(Continued) Г.Г.Шемин 2002, 23 (2):  173-181.  Abstract ( 76 )   PDF (790KB) ( 166 )   Save (omitted) Related Articles | Metrics