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01 October 2004, Volume 25 Issue 5 Previous Issue    Next Issue

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Chuxiong Basin——A Promising Oil-Gas Production Base in the Future in West China ZHANG Kai 2004, 25 (5):  463-467.  Abstract ( 734 )   PDF (1264KB) ( 198 )   Save Chuxiong basin in Yunnan province is a long-term developing and superimposed petroliferous basin with multi-deposits of marinefacies, continental-marine interaction facies and continental facies. There exist translithospheric fracture, lithospheric fracture, crustalfracture, basement fracture and caprock fracture within and around the basin. They prov ide favorable passages for oil and gas migration. Thestudy shows that it has well conditions in petroleum geology for forming a multi-superposition petroleum system with biogenetic and non-biogenetic origins and multiple types of traps dominated by anticline as well as good preservation in late period of the basin. It is concludedthat it is a medium-scale petroliferous basin with very rich hydrocarbon resources. References | Related Articles | Metrics

Effect of Yanshan Movement and Himalayan Orogeny on Hydrocarbon Migration and Accumulation in Junggar Basin ZHAO Bai 2004, 25 (5):  468-470.  Abstract ( 136 )   PDF (252KB) ( 183 )   Save The effect of Yanshan movement and Himalayan orogeny on hydrocarbon migration and accumulation in Junggar basin is analyzed.It is pointed out that the all orogenies before Yanshan movement in Junggar basin, including Indosinian orogeny, brought up the rudiment structural framework and took effects of reconstructions in detail, hence, more influencing the petroleum migration and accumulation withinthe basin. The early Yanshan movement was dominated by undulatory motion,whereas the late Yanshan movement by ascending motion,which created the conditions for hydrocarbon generated by multiple circles migrating toward overlap pinchout and lithologic pinchout zones.In the late Cretaceous, Luliang area and its south slope belt were in ascending stage, thus providing conditions for hydrocarbon formed in un-derly ing source sequences migrating upward along the unconformity and accumulating into better Cretaceous reservoirs.In the third episodeof Himalayan movement (the end of Late Pliocene), the only folding movement took place in the basin, and forming three-row anticlines at itsouth-marginal foreland sag, allowing the structures and hydrocarbon distribution to be complicated. They were not greatly effected the strataframework within the basin, but somewhat influenced the re-migration of hydrocarbons there. Therefore, the effect of Himalayan orogenyshould be considered for oil-gas exploration in southern and northern margins (Luliang and Xiazijie areas) of Junggar basin. References | Related Articles | Metrics

Gonghe Basin: ANew and Worth-Researching Basin WANG Chang-gui, LV You-sheng 2004, 25 (5):  471-473.  Abstract ( 326 )   PDF (1442KB) ( 190 )   Save Gonghe basin is located in western Qinghai province of China. It is found that its petroleum geologic conditions are similar to eastern Qaidam basin, and it could be a novel domain for exploring biogenetic gas. Well GC-1 drilled in this basin shows that it has Tertiary system with thickness of over 5 000m. Through analysis an comparison of formation, deposition, structure, hydrocarbon generation and indicator with those from Sanhu area in eastern Qaidam basin, it is believed that the similarities occur in depositional env ironment, gas source rock feature and reservoir characteristic, etc., in the two basins. It is suggested that Gonghe basin is also an ideal area for biogenetic gas, the related exploration and studies should be focused on. References | Related Articles | Metrics

Petroleum System of Mesozoic in Qiangtang Basin WU Xin-he, WANG Cheng-shan, HU Jian-hong, YI Hai-sheng 2004, 25 (5):  474-478.  Abstract ( 97 )   PDF (1968KB) ( 178 )   Save Qiangtang basin lies in mid-segment of Tethys domain in north-central Qinghai-Tibet plateau, which is a complex and special type of compound symmetric foreland basin with Tethy an tectonic style from Late Paleozoic to Mesozoic. It has widespread Mesozoic marine depo-sition and the latest marine strata with thickness of over 10,000 meters. W ell-developed and widespread source rocks with the max. thickness of more than 3,000 m are found in Mesozoic Qiangtang basin, where Xiaochaka formation (T3x) of Upper Trassic and Buqu formation (J2b) andXili formation (J2x) of Middle Jurassic are good in organic matter type and abundance as well as buried condition and distribution from matureto overmature in organic matter maturity. And it is one of major source of hydrocarbons in Qiangtang basin. This paper analyzed and classified in detail the petroleum systems such as T3x-J1q, J2q-J2b and J2x-J3s in Qiangtang basin. References | Related Articles | Metrics

Fluorite Origin and Petroleum Reservoir in Well TZ-45 in Tarim Basin ZHANG Xing-yang, GU Jia-yu, LUO Ping 2004, 25 (5):  479-482.  Abstract ( 101 )   PDF (587KB) ( 144 )   Save A special type of petroleum reservoir characterized by Ordov ician fluorite interval is found in TZ-45 Well in Tarim basin. This paper presents the researches on the fluorite-developed interval in lithology, geochemistry, reservoir geology and mineralizing geology. The comprehensive study shows that the fluorite was genetic under the epithermal env ironment without inevitable relations to Permian volcanic activities, but certain relations to the basinal fluid movement during the Himalayan orogeny. Since the basinal fluid was associated fluid for mineralization, petroleum accumulation and buried karstification, there exited the associated relations among the fluorite mineralization, petroleum accumulation and buried karstification. It is predicted that the upstream could be of developed reservoirs originated with the mineralizing fluid under the conditions of the fluorite mineralization. References | Related Articles | Metrics

Microelement and Geologic Significance of Yanchang formation in Fuxian Area, Ordos Basin ZHANG Xin-jian, FAN Ying-feng, ZHANG Jian-jun, WANG Gui-cheng 2004, 25 (5):  483-485.  Abstract ( 94 )   PDF (563KB) ( 170 )   Save Fuxian area is located in southeastern part of Ordos basin where a set of delta-lacustrine terrigenous clastic sediments with coal is found in Yanchang formation of its Triassic system. During the process of sedimentation and evolution of Yanchang formation, Chang10-Chang7 members were characterized by lacustrine expansion, whereas Chang6-Changl members by lacustrine shrinkage. Since the character and evolution of the lacustrine water body could not only prov ide the important information of the basin's depositional evolution, but also it has the great influence on the sedimentation of the lacustrine-delta sand bodies. Based on the analyses of the microelecments obtained from the mudstones of Y anchang formation in Fuxian area, this paper makes study and prediction of the property of water body, palaeoclimate and sedimentation in period of Yanchang, which could be as a good supporting evidence for study of origin and distribution of the sand bodies in Yanchang formation. References | Related Articles | Metrics

Paleo-Fluid Potential Evolution and Hydrocarbon Migration and Accumulation in Bonan Depression XIE Qi-chao, LIU Zhen 2004, 25 (5):  486-488.  Abstract ( 84 )   PDF (1500KB) ( 140 )   Save The underground dynamic fluid field, i.e. underground fluid potential, is an essential factor to control migration and accumulation of hydrocarbons. Reconstructions of paleo-fluid potential during each geological period following hydrocarbon generation may be helpful to proper recognition of petroleum reservoir distribution, which can be classified as ones of paleo-porosity, paleo-buried depth and paleo-pres-sure. This paper presents the evolution models and reconstruction methods for these three paleo-parameters, and makes analysis of paleo-fluid potential in Es4 during late Dongy ing and late Minghuazhen in Bonan depression. It is indicated that the Paleogene reservoir distribution is closely related to the paleo-fluid potential evolution and the oil-gas reservoirs could be found in low-energy env ironment of low paleo-fluid po-tehfi894-2017 China Academic Journal Electronic Publishing House. All rights reserved. References | Related Articles | Metrics

Petroleum Distribution and Accumulation Model in Mid-Segment of Foreland Thrust Belt in Southern Junggar Basin Ablimit, WU Xiao-zhi, LI Chen, LI Shi-hong, MIAO Gang 2004, 25 (5):  489-491.  Abstract ( 98 )   PDF (1677KB) ( 176 )   Save The mid-segment of foreland thrust belt in southern Junggar basin is the key area of interest for exploration of the whole basin. Comprehensive study shows that oil and gas in this area is characterized by proximal and near-faulting distribution as well as late accumulation. The main factors for controlling the petroleum accumulation are source-communicated faults and reservoir rocks. It is suggested that there exist two models of petroleum accumulation such as above source rocks-anticline-faulting-facies control and proximal distribu-tion-faulted anticline-faulting control. The related comparison indicates that in the second and third rows of anticline structural zones, thefavorable area of interest for further petroleum exploration would be the middle reservoir combination, which is of significance to guide the petroleum prospecting efforts in southem margin of Junggar basin. References | Related Articles | Metrics

Structural Style and Evolution in Dongpu Sag XU Ju-zhen, WANG Shi-kun, HUANG Jun-feng, GAO Jian-zhen 2004, 25 (5):  492-494.  Abstract ( 109 )   PDF (2402KB) ( 209 )   Save According to structural setting in formation and evolution of stretching basin, this paper presents the analysis of the stretching,strike-slipping, transforming and diapiric structural styles in Dongpu sag in terms of structure geometry. It is suggested that Palaeogene Dongpu sag was evolutive and formed under the setting of both stretching and strike-slipping processes.Such a stretching process superimposed with the strike-slipping one, the effect of south North China basin on southern Dongpu sag and the salt rock diapiric process in middle of the basin are the main factors for forming two lateral transforming structural zones,thus forming complex structural styles and struciural combinations in this sag. References | Related Articles | Metrics

Effect of Faults on Hydrocarbon A ccumulation in Wuerxun Sag DU Chun-guo, FU Guang, WANG An 2004, 25 (5):  495-497.  Abstract ( 94 )   PDF (1451KB) ( 122 )   Save There exist many faults featuring by striped distribution and multiphase activity in Wuerxun sag. This study showed that the deep major faults acted as main passages of deep inorganic CO2 migrating upward, which controlled the formation and distribution of CO2 gas reser-voirs the matched relationship between the faulting activity period and the mass expulsion period of hydrocarbon from source rocks controlled the volume of petroleum accumulation into source rocks in Wuerxun sag. There are a great deal of oil and gas expulsed from Nantun source rocks followed by migration and accumulation along late and long-term inherited faults, because of good matched relationship between the second faulting activity period and expulsion period of hydrocarbon in the sag; the major faults extending longer in plane effected as main passages on oil and gas lateral migration in the sag the good vertical sealing faults controlled the accumulation and distribution in the sag;and good lateral sealing faults dominated the formation of faulted block trap, faulted nose trap and fault-screened trap in Wuerxun sag. References | Related Articles | Metrics

Application of 3D Prestack Depth Migration in Complex Area WANG Hong-qi, LU Lie-qing, LIU Wen-qing, ZHANG Jian-wei, MENG Xiao-hong 2004, 25 (5):  498-499.  Abstract ( 62 )   PDF (948KB) ( 164 )   Save 3D prestack depth migration technique has been applied for processing of 3D prestack depth migration to some complex areas, and the results are satisfactory. The main steps can be described as follows: 1) develop time model by picking up velocity horizons in time section;2) develop interval-depth model by interval velocities layer by layer obtained by coherent inversion and stacking velocity inversion methods;3) optimize the geologic model by residual velocity analysis, and 4) achieve 3D prestack depth migration by using Kirchhoff integral method or finite differential method. References | Related Articles | Metrics

Split Processing of 3D Seismic Data from Different Vibrators YI Zong-fu, GONG Jian-qing, CHEN Zhi-gang LI Li, JIANG Zai-chao, HUANG Yi 2004, 25 (5):  500-502.  Abstract ( 77 )   PDF (1159KB) ( 148 )   Save It is normally difficult to receive 3D seismic data by using one vibrator in complex surface area. When adopting different vibrators, the seismic data processing from them has to concern about elimination of the differences among amplitude, frequency and phase. This study proposed a method for split processing of 3D seismic data in the condition of different vibrators, that is, resolving a conversion factor of one vibrator, using it into seismic data from one vibrator, and then converting the seismic data into data from another vibrator. The real data processing indicates that this method is very effective for 3D seismic data split processing of different vibrators with certain signal-to-noise ratio. References | Related Articles | Metrics

Effect of Rock Compressibility on Gas Reservoir Reserve Determination LI Chuan-liang, ZHOU Yong-yi 2004, 25 (5):  503-504.  Abstract ( 111 )   PDF (761KB) ( 212 )   Save A gas reservoir reserve determination is affected by the production data, reservoir pressure and property parameters of reservoir rock and fluid. The rock compressibility is mostly determined by lab measurement and Hall empirical equation that can be obtained from core analysis data. However, the Hall curve shows a wrong logic relation and prov ides abnormally high values of rock compressibility. With the new curve proposed by LI Chuan-liang, the rock compressibility usually appears low values in the porosity range of gas reservoir. This study indicated that the original gas in-place value calculated with the rock compressibility given by Hall curve or lab analysis will be underesti-mated obviously. References | Related Articles | Metrics

3-D and 4-Phase Multi-Compositional Model and Its Numerical Simulation A pplication MEI Hai-yan, ZHANG Mao-lin, GUO Ping, XIONG Zhong-hui, WU Shu-qiang, LI Lian-wen 2004, 25 (5):  505-508.  Abstract ( 129 )   PDF (1411KB) ( 179 )   Save Abstract:This paper presents a multi-compositional mathematical model of 3-D and 4-Phase (oil, gas, water and organic solid) and an equilibrium thermodynamic model of 3-Phase. In order to verify and evaluate the multi-compositional model, the numerical simulation study of long-core water alternate gas displacement experiment is conducted after fufilling the PVT phase behavior experiment and 3-Phase fluid phase equilibrium experiment of asphaltene precipitation. The results show that in the process of gas injection for EOR, the organic solids precipitation could occur in the oil-gas reservoir, and thus a negative effect appears on the numerical simulation results. This improved multi-compositional simulator can be used for better description of the reservoir fluid dy namic flow characters and physico-chemical features in the porous media, hence better understanding of the reservoir performance for EOR by gas injection process. References | Related Articles | Metrics

The Measures for Stable Production and Water Control in Carbonate Reservoir-An example of District A reservoir in Tahe field, Tarim basin TAN Cheng-jun, LIU Ming-gao, LI Hao, MA Xu-jie 2004, 25 (5):  509-511.  Abstract ( 64 )   PDF (718KB) ( 164 )   Save Tahe carbonate reservoir is a fractured reservoir with karst and caves related to weathering crust. It is characterized by complex and variety of reservoir bodies, very serious heterogeneity and triple porous media flowing, which result in very difficult stable production and water control in it. Since 2001, in District A of Tahe field have taken measures for the purpose of stable production and water control (SPWC). This paper presents basic procedures for SPWC, they are, strict control of producing pressure differential prior to water breakthrough, water-coning control after water breakthrough, and pumping when unflowing;_ if pumping is not effective, water plugging will be taken, if water plugging is ineffective, combine with acid treatment, if acid treatment is unsatisfied, take sidetrack drilling or water flood test. Following these measures, obv ious effectiveness and improved production indices have been found in this reservoir. References | Related Articles | Metrics

The Influence of Heavy Oil Complosition on Its Viscosity ZHU Zhan-jun, LIN Ren-zi, WANG Shuang-qing 2004, 25 (5):  512-513.  Abstract ( 113 )   PDF (1063KB) ( 217 )   Save The quantitative experiments for study of relationship between heavy oil composition and its viscosity are made. The result show sthat the relationship of exponential function occurs between percentage content of saturated hydrocarbon, aromatic hydrocarbon, neutral non-hydrocarbon, acidic non-hydrocarbon, colloid and bitumencarb in heavy oil and its viscosity. Among them, the viscosity of heavy oil decreases.with the increase of contents of saturated hydrocarbon and aromatic hydrocarbon, and increases with the increase of contents of neutral non-hydrocarbon, acidic non-hydrocarbon, colloid and bitumencarb in the form of exponential function. The degree of the influence on the viscosi-ty is as follows: colloid and bitumencarb>acidic non-hydrocarbon>neutral non-hydrocarbon, the former is the most important factor to affect the viscosity of heavy oil or absolutely contributes toit. This is coincident with the results from other experiments. Hence, to decrease the conten of neutral and acieic non-hydrocarbons collaid and bitu mencarb will effeetively decre ase the viscosity of heavy oil. References | Related Articles | Metrics

A Model for Optimizing and Controlling Condensate Gas Well Performance LI Jing-song, LI Xiang-fang, GUAN Wen-long, TANG En-gao 2004, 25 (5):  514-516.  Abstract ( 62 )   PDF (926KB) ( 168 )   Save Abstract:A model for optimizing and controlling condensate gas well performance is developed by applying the theory of complex system control, which can reflect the reservoir, wellbore and surface safety as well as maximizing economic benefit, including the approach for the model solution, by taking the equations related to reservoir multiphase flow, wellbore multiphase fluid, well bottom and surface throttling as the state equation, and taking wellbore fluid loading, reservoir critical damage, equipment critical corroding and hydrate control of wellbore and surface as restriction condition. The development and solution of this model could deal with the co-optimizing and co-controlling problems under the multifactor and multi-feedback during condensate gas well production. References | Related Articles | Metrics

The Special Approach for History Match of A Complex Fractured Reservoir CHI Jian-ping, ZHENG Qiang, QI Jun, YANG Xin-ping, ZHANG Bing, DING Yi, YANG Yu-zhen 2004, 25 (5):  517-519.  Abstract ( 77 )   PDF (676KB) ( 226 )   Save Lower W uerhe reservoir of Upper Permian in District No.8 of Karamay oilfield is a massive fractured conglomerate reservoir with edge-bottom water and extra-low permeability. This paper presents the numerical simulation studies of the complex fractured reservoir. In view of its characteristics of non-pay zone yielding, injected water leakage, watered-out and water breakthrough well, formation water inflow and different waterflooding models, several approaches for detailed history matching are adopted to over 400 wells for 23-year production, and single well pressure and water cut simulation reach the coincidence rate of 85%. These simulated results could be as a guide for numerical simulation of another similar reservoirs, and these special approaches could be applicable in other fractured low permeability reservoirs. References | Related Articles | Metrics

Effect of Gas Injection on Saturation Pressure of Volatile Oil Reservoir WEN Yu-lian, DU Zhi-min 2004, 25 (5):  520-522.  Abstract ( 116 )   PDF (865KB) ( 197 )   Save Mixing of injected gas and reservoir oil will change the initial saturation pressure, affect the deliverability of the oil. And the change of saturation pressure could affect the performance of volatile oil reservoir. This paper analyzes the effect of injected gas on saturation pressure of volatile crude reservoir under the assumed direct and complete mixing between injected gas and crude in PVT test by using the balance theory of gas-liquid two phases and field data, without consideration of effect of porous media on phase behavior. The results show that when natural gas, methane or nitrogen are injected into volatile oil sample, the oil saturation pressure will increase with incremental injected gas volume, of which the nitrogen injection assures the biggest saturation pressure, adding intermediates injected volume tends to decrease of the saturation pressure, whereas increasing overall injected volume would enable the miscibility pressure of the injected gas and crude oil to increase. References | Related Articles | Metrics

An Optimized Model of Horizontal Interval Length in Reservoir with Bottom Water CHEN Man-chao, ZHENG Lian-yong 2004, 25 (5):  523-525.  Abstract ( 83 )   PDF (542KB) ( 158 )   Save According to the balance principle of funds and the factors of both technical and economic indices for horizontal well development, an optimized mathematic model for reasonable horizontal interval length in reservoir with bottom water is developed in this paper. This model can be used to get rational length and location of horizontal intervals,production pressure differentials and economic development period considering related technical and economic factors. The prepared modeling software can be well applied in optimization of real horizontal drilling in an oilfield. The results could help the specific design of horizontal well development in reservoir with bottom water. References | Related Articles | Metrics

The Value Classification of Hydrocarbon Resources in Junggar Basin SUN Xun-guang, ZHANG Yu, LI Yong-xi, WANG Jian-feng, ZHANG Jun 2004, 25 (5):  526-528.  Abstract ( 84 )   PDF (256KB) ( 167 )   Save For onshore oil and gas development in China,1% of the gross sales revenue per year will be levied as mineral resource compensation fee by the government at present,whereas for the leased areas of onshore and offshore oil and gas development, the sliding scale rule is implemented to levy the royalty of 0~12.5%. Meanwhile, the resources tax is levied in accordance with the standard specific duty of 0~30 Yuan(RMB)/t to adjust the differential revenues of various oilfields. This is a part of available payable taxation system for oil and gas resources development in China. However, the taxation system has not taken the various differential factors and market factors of hydrocarbon reservoirs into full consideration. This paper, in view of these problems, proposes a dynamic and value-ranking method, on the basis of analysis on differential composition and influencing factors, combining with the actual performance of oilfield development in Junggar basin, with which we can evaluate the different areas, different oilfields and different oil products separately, and then determine their resources value ranks and reasonable taxation levels. In the end, the conception of levy ing the compensation fee of mineral resources in Junggar basin is presented. References | Related Articles | Metrics

Wavelet Transformation Technique for Improving Vertical Resolution in Well Logging Curves FENG Guo-qing, YANG Kun, CHEN Zhong-qiang, SHEN Yong-wei 2004, 25 (5):  529-531.  Abstract ( 81 )   PDF (1577KB) ( 167 )   Save Wavelet transformation is a new method that can make local signal analysis both in time and frequency domains, where the time domain resolution could change and increase with scale factor. The method is characterized by good localized time and frequency domain that could converge signals at any detail. By means of Mallat arithmetic, the method can be used to decompose and reconstruct well log curves, and improve the vertical resolution. Compared w ith deconvolution method, the well log curves transformed by wavelet analysis contain more detailed information and reach higher vertical resolution. References | Related Articles | Metrics

Seismic Lithofacies Analysis with Self-Organizing Neural Network YANG Shi-ming, SUN Long-de, YANG Xin-hua 2004, 25 (5):  532-534.  Abstract ( 57 )   PDF (1761KB) ( 121 )   Save Abstract:Self-organizing neural network (SONN) could be used to properly classify the studied objects according to the similarity of attributes from the objects, and avoid the shortcoming of back propagation neural network (BPNN) that learning samples have to be provided. The method by using SONN to auto-identify the seismic lithofacies from seismic data has been successfully applied in LGX oilfield of Tarim basin. From the lithofacies map, 6 faults controlled the hydrocarbon distribution in LGX oilfield, with extending in near east-west orientation, are revealed by using SONN method, which accord with the results from drilled wells. The study shows the feasibility of SONN in carbonate reservoirs. References | Related Articles | Metrics

Application of Support Vector Machine Arithmetic to Geologic Logging LIU Hong, ZHONG Da-kang, LI Wen-hua, YI Jun, HONG Zhi-qiong 2004, 25 (5):  535-537.  Abstract ( 71 )   PDF (678KB) ( 126 )   Save The support vector machine arithmetic, based on statistical theory, is presented in study of recognition of oil, gas and water zones from geologic logging. The parameters from gasometry logging and geochemistry logging and relations among induced parameters are studied, thus developing a model with help of LibSV M software, by which a novel method for recognizing oil gas/ water zone from geologic logging is proposed. The real application of this method to an oilfeld in Xinjiang shows that the support vector machine arithmetic is simple,reliable, more practical and higher accurate for use. References | Related Articles | Metrics

Improvement and Extension of Fluvial Reservoir Modeling ZHANG Chun-lei, DUAN Lin-di, XIONG Qi-hua 2004, 25 (5):  538-540.  Abstract ( 68 )   PDF (698KB) ( 138 )   Save A novel fluvial model for reservoir sedimentary facies is presented, which is characterized by extensional description and simulation of fluvial forking and crossing phenomena. According to the features of modified fluv ial model and fluvial geology and geography,a new conditioning algorithm for the model is adopted, realizing co-Boolean simulation, in which combined with sand probability model. The case study shows that the modified fluvial model contains more abundant and practical geologic information, with which the description of the fluvial deposit is more accurate, simple and fast, including upstream, downstream and branch channel. Thus, the co-Boolean simulation could allow the sedimentary facies modeling to efctively decrease uncertainty of the reservoir modeling by integrating w ith secondary information. References | Related Articles | Metrics

Generalized Water Storage and Application GAO Bo-yu, WANG Jian-bo, PENG Shi-mi, DENG Chuan 2004, 25 (5):  541-543.  Abstract ( 157 )   PDF (877KB) ( 148 )   Save Water storage is one of important parameters to describe the utilization factor of water injection energy and evaluate the effective-ness of water flooding reservoir. However, the traditional water storage could not be widely used for its limitation of concept. This paper pro-posed the definition of generalized water storage,which could reflect the effectiveness of water flooding reservoir with edge or bottom water and take the elastic energy into consideration. The case study showed that the effectiveness of water flooding reservoir can be embodied by the speed of generalized phase water storage decline; there exists different linear correlation between the generalized cumulative water storage and the water cut. References | Related Articles | Metrics

Application of Cubic Spline Interpolating Function to Calculation of Drainage Capillary Pressure HU Gang, LU Zheng-yuan, LUO Ping 2004, 25 (5):  544-545.  Abstract ( 81 )   PDF (694KB) ( 221 )   Save Many mercury-injection capillary pressure curves, which inferred from the samples of compacted and intense secondary carbonate rocks in Luojiazhai gas field, northeastern Sichuan, China, have not very good horizontal line segments. Thus, it is not easy to get the data of drainage capillary pressure. A new way to answer this problem is put forward. That is using cubic spline interpolating data to match the capil-lary pressure and its corresponding mercury saturation, enabling determination of the drainage capillary pressure to become getting the first turning point of mercury-injection capillary pressure curve. The method is not only accordant with the definition of capillary pressure curves, easy io use. but also fits the calculation of any morph ologic capillary oressure curve. References | Related Articles | Metrics

Current Situation of Researching Coalbed Gas Accumulation Units in China ZHAO Jing-zhou, SHI Bao-hong 2004, 25 (5):  546-549.  Abstract ( 75 )   PDF (277KB) ( 193 )   Save Coalbed gas accumulation unit classification and the gas reservoir-forming study are the primary bases to evaluate colbed gas re-source and units,establish the scientific programs for coalbed gas exploration and improve the success ratio of exploration. Because of the complex forming and distributing conditions of coalbed gas in China, it is especially important to study accumulation units to evaluation of coalbed gas exploration. Up to present, few of researches on this aspect have been done. This paper suggested that analyzing the existing cir-cumstance and the forming rules of coalbed gas, study ing on the formation and the div iding and accessing methods of coalbed gas accumula-tion units and researching on the styles and the models of coalbed gas reservoirs are necessary not only for direct exploring coalbed gas reser-voir, but also for improving and perfecting the coalbe gas geological theories in China. References | Related Articles | Metrics

On China-Type Petroleum Domains——In memory of WENG Wenbo's Distributions of Worldwide Oil Fields on the 50th anniversary of its publication AN Zuo-xiang, MA Ji, PANG Qi-wei 2004, 25 (5):  550-553.  Abstract ( 66 )   PDF (1301KB) ( 140 )   Save China-type petroleum domains include onshore China and adjacent belts,which is enwrapped by Asia-type petroleum domain. Such small, intensively active continental nucleus did not generate a unified platform by continental overgrowth until the end of the Paleozoic, and was. separated by the subducted and closed Tethys Sea during Mesozoic and Neozoic period, resulting in the most complex tectonic features in the world. Within the petroleum domains, the hydrocarbon-bearing Paleozoic, Mesozoic and Neozoic sequences were superimposed in a basin. With an exception of the active continental margin basins, the intra-cratonic basins had disappeared, and the foreland basins and rift basins were different from others in the world,so they an be called China-type basins. References | Related Articles | Metrics

Current Situation and Problems in China's Oil and Gas Resources Assessment ZHOU Zong-ying, TANG Yao-gang 2004, 25 (5):  554-556.  Abstract ( 113 )   PDF (265KB) ( 293 )   Save This paper briefly introduces the generals and features of all prev ious oil and gas resources assessment in China,and points out that compared with the international practice, there exist differences in oil and gas resources assessment in China such as assessment methodology, appraisement result, resource structure and resource time validity. In order to be more objective to evaluate domestic oil and gas resource potentials, it suggests to make full use of the opportunity of the new round of nation-wide oil and gas resource assessment, to rein-force the research of weak work in statistical method, geologic analogy method and the resource economy appraisement, enabling the domestic oil and gas resources assessment methodology to be more perfected by establishing such a set of assessment systems that not only accord with domestic oil and gas geologic features, but also joint with the international usual practices. References | Related Articles | Metrics

An Outline of Petroleum Seismic Geology TAN Shi-dian 2004, 25 (5):  557-559.  Abstract ( 77 )   PDF (112KB) ( 126 )   Save Petroleum Seismic Geology is a highly comprehensive integral-systematic science. It is a powerful tool for researching basinal evolution history, sedimentology, detailed structural interpretation, lateral reservoir prediction, hydrocarbon detection, reservoir description and formation pressure prediction through integration with petroleum geology and seismic prospecting data acquisition/ processing/ interpretation. And it will be a new and developing boundary science with strong vitality. References | Related Articles | Metrics

Evolvement of Oil-Gas-Water Contact and Timing of Petroleum Accumulation in Tazhong-4 Field, Tarim Basin WANG Fei-yu, ZHANG Shui-chang, LIANG Di-gang 2004, 25 (5):  560-562.  Abstract ( 95 )   PDF (1285KB) ( 170 )   Save The current OWC (COWC) and paleo-OWC (POWC) in CIHI reservoir in Tazhong-4 oilfield are found in buried depth of 2 5 10m and 2 610m, respectively, and the latter is horizontal in occurrence. The late faulting activity resulted in upward migration of crude oil in CIII reservoir,accumulation in CI and CII reservoirs,causing the POWC in CIII reservoir raising of 100m. If CIHI reservoir was formed in Late Permian and modified after Permian,a tilted or irregular POWC should exist due to tectonic movement and varied trap shapes. Therefore, when using oil-gas-water contact variation to determine petroleum accumulation period, the assumption that according to back-stripping analysis, make inverse calculation the paleo-burial depth of COWC in each well, and take the time of the paleo-burial depth with re-exhibited horizontal form of OWC as the petroleum accumulation period is unrealistic or wrong. It is impossibly so coincident that original OWC will re-exhibit a horizontal form in late period after long-term geological evolution, especially under the condition of trap shape changes. From the ge-ologic records, POWC is generally in tilted and even irregular forms. The corect method should be to identify POWC firstly, and then make determination of the related petroleum accumulation period, based on the time of earlier horizontal form of POWC. References | Related Articles | Metrics

Determination of Boundary between Upper and Lower Carboniferous in Xinjiang DU Pin-de, WANG Kun-ru, TAN Ze-jin, ZHANG Gui-zhi, ZHAO Zhi-xin 2004, 25 (5):  563-567.  Abstract ( 91 )   PDF (3341KB) ( 171 )   Save Restudy is made on Xinjiang Carboniferous sections such as mid-Tianshan mountain section, Mazatag mountain section which was measured in recent years in Tarim basin and Carboniferous section in southwestern margin of Tarim basin, as well as related drilling sections in Taklamakan desert covered area. According to the decision on the intermediate boundary of Carboniferous presented by the international stratigraphy commission, the re-determined boundary between Upper and Lower Carboniferous in Xinjiang has been placed at the upper part of Yeliemedun formation in Aqialehe section of Beluoheluo mountain of Tians han mountains, between Heshilapu formation in Mazatag section and Karawuy formation in He 'ai forestry section in southwestern margin of Tarim basin, the lower part of top limestone member of Karawuy formation in Well Lunnan-59 and the upper part of sandstone-mudstone member of Karasay formation in Well 401 in Tazhong uplift. References | Related Articles | Metrics

Dividing Qigu Formation and Toutunhe Formation of Jurassic in East Junggar Area HE Kai, HAN Jun, LI Pei-jun, PANG Yao, CAO Xin-feng, XU Huai-bao, WANG Jing 2004, 25 (5):  568-570.  Abstract ( 106 )   PDF (1148KB) ( 219 )   Save The exploration practice in recent years shows that a broad prospect appears for exploration of Shishugou group of Jurassic in east-em Junggar basin. But now something is in question about its sequence classification. The div iding criterion of south-north outerop sections are not the same; the southern wells differ from outcrop in dividing criterion,whereas the northern wells have not been divided in terms of available sequences. This paper analyzes the evolution of structure, paleo-environment and paleo-climate in this area, takes the rock color and sedimentary cycle as the primary bases for dividing Shishugou group into Qigu formation and Toutunhe formation, and thus solves the di-viding problems between wells and outcrops in Qigu and Toutunhe formations in east Junggar basin. it is suggested that the previous criterion that uses tuff to divide these two formations should be repealed. References | Related Articles | Metrics

On Oil Inorganic Origin Theory and Organic Origin Theory Y. A. Romanov, V. N. Fomin 2004, 25 (5):  571-573.  Abstract ( 116 )   PDF (125KB) ( 127 )   Save Comparison and Analysis are made on theoretical bases of oil Inorganic and organic origins. It is approved from a great number of geochemical data that hydrocarbons could be formned from CO, CO2 and H2 in global inorganic synthetic zones by geologic evolution process to a great extent. Related Articles | Metrics

On China-Type Petroleum Domains-In memory of WENG Wenbo's Distributions of Worldwide Oil Fields on the 50th anniversary of its publication AN Zuo-xiang, MA Ji, PANG Qi-wei 2004, 25 (5):  574-578.  Abstract ( 103 )   PDF (1322KB) ( 140 )   Save China-type petroleum domains include onshore China and adjacent belts,which is enwrapped by Asia-type petroleum domain. Such small, intensively active continental nucleus did not generate a unified platform by continental overgrowth until the end of the Paleozoic, and was separated by the subducted and closed Tethys Sea during Mesozoic and Neozoic period, resulting in the most complex tectonic features in the world. Within the petroleum domains, the hydrocarbon-bearing Paleozoic, Mesozoic and Neozoic sequences were superimposed in a basin. With an exception of the active continental margin basins, the intra-cratonic basins had disappeared, and the foreland basins and rift basins were different from others in the world, so they can be called China-type basins. References | Related Articles | Metrics