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01 February 2004, Volume 25 Issue 1 Previous Issue    Next Issue

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Divergent Role of "Emei Tafrogeny" on Yangtse Palaeoslab and Tarim Palaeoslab and Its Significance in Geoscience LUO Zhi-li, YONG Zi-quan, LIU Shu-gen, ZHAO Xi-kui, SUN Wei 2004, 25 (1):  1-7.  Abstract ( 121 )   PDF (2670KB) ( 572 )   Save Many Chinese scholars in geosciences believe that in Early Paleozoic，Yangtse palaeoslab was linked with or not far from Tarim Palaeoslab，based on similarity between palaeobiocoenosis and sedimentary facies. This paper discusses the divergence and convergence of these two slabs and their kinematic features from the "Xinkai tafrogeny" and "Emei tafrogeny" emerged in tectonic evolution history of Paleozoic slabs in China, and sets forth the dynamic mechanism of Y angtse palaeoslab drifting to east from the theory of "Emei mantle plume" . The study suggests that if the judgment of these divergence and drifting to east is acceptable, that Tetys within border of China should be opened first is fimly supported, which is also of big significance in theory of geology to studying global Permian basalt erupting in large scale and simultaneously in some places. In addition, they have much more implications for studying the events of broad biogenic extinction during Late Permian and Early Triassic; for finding out metal deposits of vanadium and titanium magnetite in Altun block and adjacent areas; particularly,for searching for giant oil-gas fields of Lower Paleozoic in Tarim basin. References | Related Articles | Metrics

Gas Property of Upper Paleozoic of Craton Blocks in North China Platform AN Zuo-xiang, MA Ji 2004, 25 (1):  8-12.  Abstract ( 97 )   PDF (1112KB) ( 458 )   Save The first giant gas field-Sulig gas field and Qinshui gas field in Shanxi province come out with in China in resent years, their gas producing zones Carboniferous Permian when deposited could be div ided into the northern, central and southern belts like craton block of North China platform，and have broad source conditions. During Indosinian, Yanshan and Himalayan movements，the North China's craton was separated into six blocks，forming very different conditions of hydrocarbon migration and accumulation. W here the structures were simple and Triassic covers Carboniferous-Permian， gas fields or pools were favorably protected. It is concluded that in Erdos and Qinshui areas should perform further ex ploration; in Bohai Bay basin should pay attention to in-depth study of secondary hydrocarbon generation and migration; in Fraghe gdbenibasiou ewby lobaotrhioimus ibrgaklooggh hlpaigslfos sesprospecting. References | Related Articles | Metrics

Formation and Evolution of Triassic Qiangtang Basin in Qinghai-Tibet Plateau ZHENG Meng-lin, LIU Chi-yang, WANG Ding-yi 2004, 25 (1):  13-16.  Abstract ( 140 )   PDF (2006KB) ( 393 )   Save The formation and evolution of Triassic Qiangtang basin are controlled by Lazhulong-Xjjinwulan rift and Bangonghu-Dingqing rift. In .early and middle Triassic, the basin is at the beginning of the formation and the deposition is limited in northwestern part of it. In the early peri- od of late Triassic, these two rifts initiated shaping and by the basin's faulting and subsiding, three formations are developed as clastic formation,carbonate formation and mediate-basic volcanic formation. During the middle period of late Triassic，the basin is in relative stable stage completely submerged by sea water. In the late period of late Triassic, Lzhulong-Xijinwulan rift is closed followed by large-scale marine regressing,hence the depos itional formation dominated by sand-shale intercalated with coal seam or "coal line" is shaped. References | Related Articles | Metrics

Prospects of Hydrocarbon Exploration of Permian in Turpan-Hami B asin WANG Chang-gui, YANG Biao 2004, 25 (1):  17-21.  Abstract ( 109 )   PDF (335KB) ( 305 )   Save Permian is broadly distributed in North Xinjiang area, and source rocks are principally developed in upper member of Middle Per-main and upper member of Lower Permian. Abundant petroleum resources are found in the petroleum systems where oil source came from Per-mian in Junggar basin. In Turpan-Hami basin, there exist definite potential of petroleum resources in its Permian and fundamental petroleumgeologic condition for forming oil-gas reservoirs. At present, the Permian is still in early stage of exploration for its low extent of prospecting.Study shows that the favorable targets for hydrocarbon accumulation zones with Permian oil source could be the three uplift belts such as Take-quan-Shanshan, Turpan- Pubei and Kuqa in surroundings of Taibei depression and lowland of Bogoda mountain front. References | Related Articles | Metrics

Faulting Characteristics and Effects on Hydrocarbon Distribution in Qaidam Basin CHEN Shao-jun, LUO Qun, WANG Tie-cheng, HU Yong 2004, 25 (1):  22-25.  Abstract ( 97 )   PDF (1113KB) ( 349 )   Save controlling roles of basinal fault can be div ided into the five classes: Class I fault controls the structural evolution and sedimentary develop-ment; Class II fault is as key boundary line for classification of the structural units and for controlling source rock provinces; Class III fault con-trols the formation and distribution of various structural traps; Class IV fault controls the development and evolution of local structural traps; andClass V fault is of destroy roles to the structural traps or make the structural traps complicated. There exist four types of faults or six originaltypes of faults, which control eight original types of structural traps, in which the most significant traps are fault-extending anticline, thruststructure and fault-slipping anticline ones. In the hinterland of this basin, there are developed fault structural belts with great hydrocarbon po-tentials and low extent of exploration efforts. The study shows that the trap belts with developed fractures in the center or surroundings of thesource rocks will be the most favorable targets for breakthrough of exploration. References | Related Articles | Metrics

Structural Feature in Kumux Basin and Its Exploration Prospecting HU Jian-feng, LIU Yu-kui, ZHENG Duo-ming, LIU Hu 2004, 25 (1):  26-28.  Abstract ( 131 )   PDF (975KB) ( 296 )   Save Kumux basin is located in eastern sector of South Tianshan Mountains, characterized by developed faulting with sinistral property.The fault assemblage relations are analyzed. There are four stages in structural evolution of this basin. It was an extensional and faulted basin inMesozoic, and then developed into an intermountain basin with compressed strike-slip attribute in Cenozoic. Study shows that Kumux basin is ofbright exploration prospecting for its two sets of major source rocks, good reservoir-seal assemblage and multi-trap types. It is considered fromanalysis that the recent petroleum exploration should pay more attention to Xiaoer-Y ang Bulak depression with thick sediments, deep buriedsource rocks and near the center of the basin. Yang Bulak sag located at the deepest within the depression is the most favorable potential areafor petroleum exploration. References | Related Articles | Metrics

Gas Accumulation Characteristics in Baijiahai-Wucaiwan A rea HU Pingl, SHI Xin-pu, XU Huai-bao, TAN Qiang, WU Jun-jun 2004, 25 (1):  29-32.  Abstract ( 99 )   PDF (991KB) ( 287 )   Save Baijiahai-W ucaiwan area is in line intersection of multiple source sags in eastern Junggar basin, with multiple hydrocarbon sourcerocks composed of Carboniferous continental-oceanic interaction deposits, Permian Pingdiquan formation and Triassic Xiaoquangou group lakemudstone, and Jurassic coal measure strata. It is characterized by multi-filled oil in the early time and gas in the late time. Commercial gas flowis output from Carboniferous Tamugang formation and Batamayineishan formation, Triassic Shaofanggou formation, and Jurassic Badaowan, San-gonghe and Xishanyao formations. The source rocks in deep of north sag of Dongdaohaizi and Changji sag have been in matured-over maturedstage, which contribute much to gas reservoir in Baijiahai salient; while the source rocks in Carboniferous Dishuiquan and Batamayineishan for-mations in W ucaiwan sag have reached the matured stage. Natural gas in Baijiahai salient is mostly distributed near the gas-generated centerand by way of close distance migration and accumulation, form gas reservoir(s). W ucaiwan sag is dominated by gas reservoirs with both sourceand reservoir in Carboniferous system. References | Related Articles | Metrics

Establishment of Jurassic Sequence Framework in Turpan-Hami Basin QIN Chang-wen, LI Hong-wei, JIANG Bing 2004, 25 (1):  33-36.  Abstract ( 97 )   PDF (1865KB) ( 273 )   Save Turpan-Hami basin is a continental petroliferous basin in which Jurassic is its major prospected stratum. By using theory and methodof high-resolution sequence stratigraphy, comprehensive studies of the outcrop section, drilling and seismic data are made, and the Jurassic isdivided into seven sequences (SQ,-SQ-). SQ, corresponds to Badaowan formation and Sangonghe formation; SQ, to the first, second and thirdmembers of X ishanyao formation;SQ3 to the fourth member of Xishanyao and the first member of Sanjianfang formation; SQ4 to the second andthird members of Sanjianfang; SQs, SQ6 and SQ- to Qiketai, Qigu and Kalazha formations, respectively. The coal measures source rocks are mostdistributed in the upper part of SQ1 and SQ-base-level rising hemicyclothem; the reservoir mainly in SQ,-SQ5 rising hemicyclothems. The SQ3,SQ4 and SQ5 base-level falling lenicylothemas well as SQ6 and SQ6 and SQ7 are the majorizons sf regional cap rocks in this basin. References | Related Articles | Metrics

Geochemical Methods for Identification of Continental Sequence Interfaces ZHAO Jun-qing, JI You-liang, ZHANG Shan-wen 2004, 25 (1):  37-40.  Abstract ( 91 )   PDF (1606KB) ( 159 )   Save Clay minerals and trace elements are universally distributed in various deposits and sedimentary rocks. They are extremely sensitiveto environmental changes. And the characteristics of their sedimentary differentiation and combination as well as mineral composition and con-tents have recorded the changes of various environmental factors when they formed. It is of an important indicating significance to reconstructpaleo-env ironment and to study continental lake basin's varied water depth. Taking each sequential element of the third member and the fourthupper member of Shahejie formation in Sengbei fault' 's downthrow, Dongy ing sag as an example, the lithologic geochemical ty pomorphic parame-ters are studied. It is suggested that in cyclic lake-level changes controlled by paleo-climate, cyclic changes could occur in mineral composition(clay minerals and cements), chemical composition (trace element), etc., in sedimentary rocks. References | Related Articles | Metrics

Study on Organic F acies of Jurassic Coal Measure Source Rocks in Y anqi Basin YAN Yong-xin 2004, 25 (1):  41-43.  Abstract ( 79 )   PDF (719KB) ( 275 )   Save Yanqi basin is one of the small coal-bearing basins of Mesozoic and Cenozoic in W est China. Since 1993, two oil-gas fields with fouroil-bearing blocks have been found successively. The Jurassic source rocks in coal measure strata are mainly distributed in Bohu depression,forming Jurassic petroleum system. Through quantitative statistics of petroleum micro-constituents from wells by sample analysis and study ofvarious coal-measure facies parameters in Yanqi basin, it is found that they are high in gelation index and low in plant tissues restoring index,proving that most coal measures are formed reducing environment with weak water mobility. The coal measure facies can be divided into fiveones such as dry peat marsh, moist forest peat marsh, transitional margin marsh, living water peat marsh and open water facies. It is pointed out .that the coal-bearing formation in transgressing sequences is favorable environment for hydrocarbon generation in Jurassic coal measure sourcerocks in Yanqi basin. References | Related Articles | Metrics

Seismic Data Imaging Technique in Deep Complex F aulting Area --An example of Qianmiqiao area in Dagang oilfield ZHANG Jian-wei, CHENG Qing, QIANG Fang-qing, YUE Fu-sheng 2004, 25 (1):  44-46.  Abstract ( 96 )   PDF (731KB) ( 248 )   Save A key technique is put forward by analy zing the seismic data from deep strata of Dagang oilfield in East China. The technique is tocombine the prestack depth migration with model processing for improv ing the signal-to-noise ratio, namely in common reflection point (CRP)trace gather of prestack depth migration, realizing its zero time-shift stacking,by application of the model-based noise attenuation and model-based static correction methods. This tight combination bet ween the model constraint and the seismic interpretation can have the seismic datafrom deep strata better imagined, thus obtaining good results for geologic interpretation. References | Related Articles | Metrics

Prediction of Seismic Velocity or Lithology in Fudong Slope Belt in Eastern Junggar Basin JIN Bo, LIU Zhen, WU Chang-wu, DANG Hu-qiang, HAN Jun, GUAN Qiang 2004, 25 (1):  47-49.  Abstract ( 94 )   PDF (1229KB) ( 304 )   Save The velocity spectrum data from Fudong slope belt in eastern Junggar basin are analy zed and interpreted, the compacting models oftwo types of detailed sandy mudstone using drilling and well log data are developed. Based on these, the conversion of interval velocity,correction of spectrum-based interval velocity and correction and smoothing of sand exponential-calculated error are conducted using seismicvelocity lithological interpretation system (VLIS), obtaining the estimated interval velocity and sand exponent of Mid-Upper Jurassic Shishugougroup, respectively. Through seismic interval velocity analysis and lithology prediction, integrated with characteristics of seismic facies andsedimentary facies, the high sand exponent areas are corresponding to foreset and filled facies, which reflect that the source in this area is mainlyfrom deposits to east-north direction, and provide quantitative basis for predicting the favorable reservoir facies belts in Fudong slope belt. References | Related Articles | Metrics

Correlation of Mean Velocities between Sonic Logging and VSP Logging ZENG Zhao-rong, XIAO Ling, BAI Xin-ying, LV Qing-sheng 2004, 25 (1):  50-52.  Abstract ( 153 )   PDF (873KB) ( 247 )   Save There are some errors between mean velocity of formations obtained from sonic logging compared to VSP logging, which are mainlyresulted from cumulative time errors in sonic logging, and closely related to well condition, wellbore interval and its formation. Therefore, duringhorizontal calibration and time-depth conversion by means of sonic log mean velocity, it is necessary to correct the existed errors in order to meetrequirements of more and more exploratory precisions. References | Related Articles | Metrics

Easy Determination of Water Influx in Reservoirs LI Chuan-liang, XIAN Li-dong 2004, 25 (1):  53-54.  Abstract ( 134 )   PDF (647KB) ( 431 )   Save This paper presents two methods for easy determination of water influx in reservoirs based on material balance theory, i.e., the NetProduction Volume Curve and the Production Index Curve. These methods can be used for estimation of water influx in reservoirs without anyassumption of aquifer shape and size by apply ing the production performance data. Hence the tedium of the conventional trial-and-error cailculation and obnious uncerlainty couldbe overcome imapplication of the easy and pract cal new methods References | Related Articles | Metrics

Numerical Simulation of Jurassic Sangonghe Reservoir in Mobei-2 Wellblock, Junggar Basin FENG Guo-qing, CHEN Jun, ZHANG Lie-hui, SONG Yu-xin 2004, 25 (1):  55-57.  Abstract ( 101 )   PDF (462KB) ( 232 )   Save The Jurassic Sangonghe reservoir in Mobei-2 W ellblock is a typical gas-cap pool where the gas cap volume is 0.91 times as big as itsoil ring's. With the application of reservoir numerical simulation method, the rational development process for gas-cap pool is studied. The sim-ulation and design of various processes such as depletion drive, waterflooding, injection-withdrawal ratio and gas-cap production, etc., are per-formed,based on modified geological model by production history matching of Sangonghe reservoir. The simulated results show that it is themost favorable to adopt waterflooding process that two rows of injection wells are arranged respectively in inner part of oil-water contact and out-er part of oil-gas contact, and keep injection-withdrawal ratio of 1.0; simultaneously, an equilibrium gas well to be drilled on the gas cap for oilring development is available to obtain higher recovery percent of reserves. References | Related Articles | Metrics

The Effect of Two Mediums Injection on Crude Property XIONG Yu, GAO Ping 2004, 25 (1):  58-60.  Abstract ( 159 )   PDF (1172KB) ( 280 )   Save The effect of medium injection on PVT properties of crude is studied as one of evaluation means in laboratory for EOR by gas injec-tion process. Injection of rich gas and N2 followed by study of the variations of PVT parameters of crude is the basis of making laboratory evalua-tions for different displacement processes as trailing edge miscible flooding,front miscible flooding and non-miscible flooding. On the basis ofPVT analysis of actual light oil, a rich gas and N2 injection experiment and N2 multi-contact experiment are studied, respectively, including com-parison of variations of oil phase behavior, saturated pressure, viscosity, B,, GOR and p. after injection of these two gases. In addition, the effectof N, extraction on the PVT properties is analyzed. The results show that similar variation of PVT properties for rich gas and N2 injection occurswhen the one- contact miscible flooding, but N, is not so good as rich gas in improvement of crude viscosity, volume factor and density, as a resultof quick increase of oil saturated pressure; also, under N flooding, the trailing edge miscible formation crude will become heavy quickly, result-ing i0peloc 2fletichessbyca dooding lionnacherongt laDEnd ludilig lhingnisoide diplacigheht.reserved. References | Related Articles | Metrics

Application of Pyrrolic Compounds in Analysis of Hydrocarbon Migration and Recharging Regularities in Cainan Oilfield, Junggar Basin WANG Chuan-gangl, WANG Tie-guan, XIE Ming-liang, YAO Ai-guo, WANG Jun-huai, LIU Hong-wei 2004, 25 (1):  61-64.  Abstract ( 100 )   PDF (1274KB) ( 179 )   Save Pyrrolic nitrogen-bearing compounds are used for trac ing crude migration and recharging processes of Jurassic Sangonghe reservoir inmajor blocks of Cainan oilfield, Junggar basin. In the pyrrolic compounds contain a great amount of alkycarbazoles, a lttle amount of bensocar-bozoles and ittle dibenzocarbazoles. Based on the ratio of 1 ,8-dimethy lcarbazole/ 2,4-dimethy lcarbazole, C,-carbazole/C,-carbazole, G1/G3and the relative amounts of ankycarbazoles and alky benzocarbazoles, it is suggested that there exist different recharging regularities in bothsides of faulting along Well Cai-001-Well Cai-007 in eastern block of Cainan oilfield: in the east side, oils recharged into reservoir from southand north directions, and migrated towards W ell Cai- 1001 and Well Cai-006; in the west side, oil recharged into reservoir just from south direc-tion, and entered into center of the fault-nose uplift followed by recharging towards west structural highs along passage of the fault. References | Related Articles | Metrics

Study on the Generalized Arc-Tangent Distribution Production Decline Equation SUN Yu-kai, GAO Wen-jun, LIU Ying, XIAO Zhi-peng 2004, 25 (1):  65-67.  Abstract ( 79 )   PDF (1064KB) ( 334 )   Save The available classical decline equations can't be used for effectively explaining the production decline curves protruding rightwardslightly and the declining rate curves being convex early and concave later. From fluid mechanics in porous medium, this paper educes a newgeneralized production decline equation for dealing with these problems. Also, it can be used for interpreting both why the monotone decreasingappears in production decline curves and the monotone increasing early and monotone decreasing later in them. Based on these, the paper stud-ies and analyses the decline equation and corresponding relative permeability to oil and production decline rate vary ing with the characteristicparameters. These can prov ide theoretical ground to select and apply the decline equation. This decline equation is directive significance theo-reilkl)y4at0 lslialyAcademic Journal Electronic Publishing House. All rights reserved. References | Related Articles | Metrics

Economical L imitation of the Stimulation of Conglomerate Reservoir for High-Water Cut Stage in Xinjiang Area DONG Guang-hua, SHI Jun, ZHU Ya-ting, CHEN Yu-chuan, WANG Lei 2004, 25 (1):  68-71.  Abstract ( 85 )   PDF (449KB) ( 225 )   Save The conglomerate oilfield in northwestern margin of Junggar basin has its recovery percent of recoverable reserves of 71.24% andcomposite water cut of 70.7% at present. For the characteristics of the conglomerate reservoirs with high water cut, effctive stimulations shouldbe comprehensively applied to gain better exploitation effectiveness, and economical limitation for the stimulations be determined to providedecision-making basis for investment of the stimulations. 'The economical limitation water cut for highwater cut conglomerate reservoir is definedas quasi-economical limitation water cut and economical limitation water cut. According to changes of stimulation cost, operation varied cost andoil price, the chart related to the stimulation economical limitation and oil price, stimulation cost, operation varied cost is developed. And takingClass I, lI, III typical conglomerate reservoirs in northwestern margin of Junggar basin as examples, quantitative estimation and analysis aremade in the limitation. 'The application of this method will allow to effectively decrease the composite run cost of the stimulations and thus to fur-rtereyrereaecalateefstteiai Electronic Publishing House. All rights reserved. References | Related Articles | Metrics

Discussion on Open-Flow Potential Equations of Gas Wells in Tarim Basin LI Yong, LIU Qi-guo, GAO Guo-xi, YU Xin-qi 2004, 25 (1):  72-73.  Abstract ( 152 )   PDF (831KB) ( 226 )   Save Using the conventional estimation methods, this paper analyzes the deliverability test data of high-pressure gas wells in Tarim field,discusses the relationship between pseudo-pressure analysis and pressure analysis methods, and develops empirical correlation between open-flow potential estimation in forms of pseudo-pressure and square pressure for high-pressure gas wells, providing a new single-point open-flowpotential equation suitable for both forms. The estimations from many cases show that the results from the equation are accordant with those fromthe productivity test data analyses such as conventional test, isochronal test and modified isochronal test. This equation is practical and reliablefor forecasting the production performance of high-pressure gas wells, and helpful to guarantee the reasonable development of the gas wells. References | Related Articles | Metrics

Multi-Objective Optimization Method for Calculating the Reasonable Well Spacing Density of Oilfield LIU Xiu-ting, WANG Sheng-yi, YANG Jun 2004, 25 (1):  74-76.  Abstract ( 75 )   PDF (265KB) ( 278 )   Save In order to make up the shortcomings of available methods for calculation of reasonable spacing density, this paper develops a multi-objective optimization method based on modified B.H.IIe/IKaYeB recovery factor-well spacing density formula, integrated with economic analysisand dynamic economic analysis method and optimal control theory. This new formulae for multi-objective reasonable well spacing density isused for estimation of light and heavy oilfields or blocks for verify ing its feasibility and validity. The results are satisfactory. References | Related Articles | Metrics

The Relationship among 12 Generalized Models for Production Prediction of Oil-Gas Fields YANG Xing-hua, LIU Ying 2004, 25 (1):  77-79.  Abstract ( 79 )   PDF (272KB) ( 203 )   Save By selecting different characteristic parameters of the general ized mathematic model for production prediction of oil-gas fields given inthe literalture [l], 12 types of related models are obtained such as W eng cyclic model, log normal distribution model, Rayleigh prediction model, Betacyclic model, Hubbert resource prediction model, HCZ model, Arps decline model, Kopatov decline model, etc., among which W eng cyclic model .and others for production prediction are the special cases of generalized mathematic model in the literature [1]. Therefore, the general formula forgeneralized mathematic model can be used to establish relations between other models for production prediction and generalized mathematic tipgngeleteadgilavelforltlye therpreodegfefieigligiureicdifofigieiyiveignience fotfefedeuse. References | Related Articles | Metrics

Application of Exponential Decline Method in Condensate Gas Reservoir TAO Zi-qiangl, , YU Yuan-zhou, YANG Guang-rong, SUN Bing, CHEN Y uan-qian 2004, 25 (1):  80-83.  Abstract ( 60 )   PDF (1368KB) ( 185 )   Save Exponential decline is an important forecasting method in oil and gas reservoir engineering. It can be used for prediction of produc-tion, cumulative production and recoverable reserves in depletion stage. The method is applied in prediction of condensate gas reservoir, andbetter results have been obtained. It is concluded that the decline regularities of the total well fluid production, dry gas production and conden-sate production accord with the exponential decline rule. References | Related Articles | Metrics

Application of Detailed Structural Interpretation in Tahe Oilfield Development AN Jing-wen, YANG Zi-chuan, ZHAO Jiang 2004, 25 (1):  84-86.  Abstract ( 88 )   PDF (5927KB) ( 184 )   Save Since development of Tahe oilfield that has converted from exploration, the available 3D seismic interpretation methods have not metthe demands of well arrangement precision in stage of petroleum development. Detailed calibration of seismic data and detailed interpretation ofstructures will be conducted as necessary. In this paper, new techniques at home and abroad such as multi-well composite calibration and 3Dvisible data correction, etc., are selected and applied. The results show that work efficiency of seismic interpretation can not only be improved,but also the accuracy of time-depth conversion and structure mapping be guaranteed, forming a set of technical methods for meeting interpreta-tion and mapping accuracies in stage of development. References | Related Articles | Metrics

Application of Modern Well Test Analysis in Y aha Condensate Gas Field, Tarim Basin CHEN W en-long, WU Nian-hong, YANG Yong, XIANG Wen-gang, LU Ai-lin 2004, 25 (1):  87-89.  Abstract ( 77 )   PDF (315KB) ( 313 )   Save Yaha field is the largest integrated condensate gas field developed by the cyclic gas injection with high pressure. The condensate gasreservoir is a special and complex gas reservoir, in which condensate hydrocarbon system flows in strata with complicated phase behaviorchanges during the development, and many specific factors affecting condensate oil-gas fluid flow appear compared to a conventional gas reser-voir, such as phase behav ior change of fluid in strata and wellbore as well as oil and gas two-phase flow in the porous media, etc. So the well testanalysis of condensate gas wells is different from other wells. In light of this speciality, a relatively complete set of well test analysis techniquesfor condensate gas wells is successively applied in Yaha field by means of related basic theories and cases. In addition, using past three-yearwell test interpretation results, the reservoir parameter, boundary identification, gas well productivity and pollution effect caused by retrogradecondensation of this field are analyzed for proper recognition of production performance of the condensate gas wells or reservoirs. The results canhelp9rAvd0 bcealifira baseS folina forlborleaelmetrqnigrdmblishing House. All rights reserved. References | Related Articles | Metrics

Discussion on the Mid-Crust and Its Geological Implication ZHANG Jing-lian, YU Jun-min 2004, 25 (1):  90-94.  Abstract ( 174 )   PDF (314KB) ( 429 )   Save The deep structure of the earth crust is a topic focus. The relation among petroleum, metal deposit, earthquake and mid-crust is con-cerned. Low seismic velocity, high conductivity (low resistance), low density are the important geophysical features of the mid-crust. The investi-gation shows that when the seismic velocity of the mid-crust Pp<6.0 km/s, p<2.75 g/ cm', there exist hydrocarbon generation and oil-gas reser-voirs; when Vvp>6.0 km/s, p>2.75 g/cm', there exist Fe, Cu, Ni, Au and other metal deposits. To study the geological features of the mid-crust isof significance for exploration of oil-gas and metal deposits, particularly, for big and giant oil-gas fields and metal deposits, and for prediction ofthe earthquakes as well. References | Related Articles | Metrics

Continuable Development of Oil-Gas Field Exploitation Needs Support of Theories about Multi-Stage A ccumulation and EOR/IOR GUO Zhan-qian 2004, 25 (1):  95-100.  Abstract ( 83 )   PDF (351KB) ( 212 )   Save Traditional concept suggests that an oil-gas field is in static equilibrium for single-stage charging, and the more producing, the lessremained for amount of hydrocarbons, being accordant with subtraction rule in mathematics. However, exceptions are found by the proofs ofw ithdrawals much more than estimated reserves in some fields such as Romaskino and Groznei oilfields in Russia, and Daqing oilfield in whichH,S occurred in high-water cut stage of development. The facts show that hydrocarbons regenerated and from deep crust could be recharged intothe oil-gas fields rather than oil-gas fields is merely in static equilibrium for single-stage charging. The present crust movement can providepower for displacement and also passages for recharging oil-gas into related reservoirs. The domestic trace element analysis suggests that thetrace element content in crude is generally higher than the mean trace element content in continental crust, including the higher density. Underthese circumstances, it is not suitable for most oil-gas fields to adopt EOR technologies taking water injection as medium or supporter, but toapply gas injection (CO, N2, and H,S) for petroleum development. References | Related Articles | Metrics

Questions on Application of Fractal Method in Studying Pore Structure in ReservoirRock before and after Waterflooding- ·A discussion with Mr. MA Xin-fang, et al. HE Cheng-zu 2004, 25 (1):  101-102.  Abstract ( 63 )   PDF (189KB) ( 155 )   Save Mr. Ma Xin-fang, et al., published the paper Application of Fractal Method in Study ing Pore Structure in Reservoir Rock before andafter W aterflooding on periodical Xinjiang Petroleum Geology, No.3, 2003. The most important part or key point of this paper is the mathematicmodels and their deductions. However, these models and deductions are almost the same to those of prev iously published two literatures writtenby others. Is this real coincidence or questionable plagiary? Mr. Ma should make some explanations for them as necessary. It is believed thatearnest readers will make a proper judgement of this question. References | Related Articles | Metrics

Questions on Reverse Structure in China Petroleum Provinces -- A discussion with Mr. CAI Xi-quan and Mr. WANG Tong-he TAN Shi-dian 2004, 25 (1):  103-105.  Abstract ( 92 )   PDF (117KB) ( 281 )   Save Different comments are proposed on the viewpoints of a book Reverse Structure in China Petroleum Prov inces written by Mr. CAI Xi-quan and Mr. W ANG Tong-he. The author points out that the meaning about reverse structure was a contradiction in terms, and great numbersof cases listed in this book disobeyed the principles of reverse structure recognition; to divide the reverse structure into positive one and negativeone was acceptable, but no recognizable indicators for them were given; the aspects for favorably forming oil-gas reservoir were expounded, butthe destructibility of reverse structure to oil-gas accumulation was ignored in the book. In addition, it is improper to cite so many others' litera-tures without any notes of derivations. References | Related Articles | Metrics

Global Regularities of Spacial Distribution of Oil-Gas Fields V. I. Sizykh, R. M. Semenov, V. A. Pav lenov 2004, 25 (1):  106-109.  Abstract ( 125 )   PDF (1928KB) ( 299 )   Save Abstract:The article treats the problem of paragenetic relationship between mobile and seismic belts and gas-bearing deposits of the world.Such a comprehensive approach has been never used in geological practice, and we are the first apply it to resolve the problem. The result of re-search represents a substantial advance in understanding of the global regularities of spacial distribution of the world hydrocarbon reserves. Mo-bile and seismic belts are the "indicator" structures controlling the major oil and gas bearing provinces of the world. The authors hope that thearticle will be of interest to broad scientific readership. Related Articles | Metrics

Petroleum Geology and Favorable Zones for Hydrocarbon Exploration in Llanos Basin, Colombia ZHU Yi-xiu, LIU Luo-fu, JIN Qiang 2004, 25 (1):  110-113.  Abstract ( 168 )   PDF (855KB) ( 446 )   Save An integrated study on lithology, sedimentology, structural evolution and petroleum geology in Llanos basin of Colombia is made. Thechief source rocks are Guadalupe (K2) marine shale and carbonate rocks, major reservoir rocks are the shore-river-delta quartzose sandstone ofUpper Cretaceous to Oligocene, and regional cap rocks are Miocene Leon thick shale. The principal period for hydrocarbon migration and accu-mulation occur after the Miocene. The traps are classified into three ty pes: Tertiary trap group, Cretaceous trap group and composite trap groupbetween Tertiary and Cretaceous in overthrust frontal belt. Late Cretaceous to Early M iocene is the period of these traps formation. It is suggest-ed by comprehensive analysis that Llanos overthrust frontal belt is the favorable area for petroleum exploration, followed by the Apiari grabenand the Barinas depression, and the Llanos depress ion and Arauca graben are of certain potentials for hydrocarbon prospecting. References | Related Articles | Metrics

Easy Determination of Water Influx in Reservoirs LI Chuan-liang, XIAN Li-dong 2004, 25 (1):  114-115.  Abstract ( 113 )   PDF (381KB) ( 149 )   Save This paper presents two methods for easy determination of water influx in reservoirs based on the material balancetheory of reservoirs, i.e., the Net Production Volume Curve, and the Production Index Curve. These methods can be used for esti-mation of water influx in reservoirs without any assumption of aquifer shape and size by applying the production performancedata. Hence the tedium of the conventional trial-and-eror calculations and obvious uncertainty could be overcome in applicationof the easy and practical new methods. References | Related Articles | Metrics

Plays for Giant Oil Field Prospecting in Junggar Basin HE Deng-fa, ZHANG Yi-jie, WANG Xu-long, JIA Jin-dou, SHI Xin 2004, 25 (1):  117-121.  Abstract ( 119 )   Save Junggar basin is one with abundant hydrocarbon resources,low degree of exploration and great potentials for oilprospecting. For further petroleum exploration, its wedge-like structure with shallow or thin strata in the north and deep or thickstrata in the south and regional monoclinal structure would be the realistic domains by their determinants for the fact that thesubtle trapping oil-gas reservoirs such as low -amplitude anticline,faulting-lithologic and stratigraphic-lithologic types are primarilydeveloped in middle- and shallow. -buried Jurassic-Cretaceous in the hinterland of Junggar basin; its complex superimposed struc-tural belts shaped by intense thrusting and compresso-shear actions would be the strategic breakthrough domains; while the deep-buried large -scale structures of Carboniferous to Triassic in hinterland of the basin should be the important successive domains. Inaddition, Junggar basin has a characteristic of multiple incremental peaks in oil-gasreserves or OOIP/OGIP. In recent 10 years,much more reserves have been found out from the subtle reservoirs and the middle-deep reservoirs.Hence subtle reservoirs havebecome major targets for further hydrocarbon exploration in Junggar basin. References | Related Articles | Metrics

Complex Petroleum System in Kongquehe Area of Tarim Basin ZHANG Ke-yin, SHAO Zhi-bing, ZOU Yuan-rong 2004, 25 (1):  122-124.  Abstract ( 88 )   Save The basinal source rocks of Cambro-Lower Ordovician and Jurassic limnetic source rocks occurred in Kongquehe areaof Tarim basin appear in form of multiple oil-gas assemblages and zonal distribution of local structures, with process of multi-stagehydrocarbon accumulations and deconstructions.The existing reservoirs were shaped in period of Late Y anshanian and Himalayanmovements. The complex petroleum system is proved by continuously exploratory results. The study shows that the structural beltsin N-W trend situated in hydrocarbon-generated center of Jurassic and secondary hydrocarbon-generated superimposed area ofCampro-Lower Ordovician possess greater potentials for petroleum exploration. References | Related Articles | Metrics

Reservoir Characteristics of Yan 'an Delta XU Zheng-yu, DONG Yi-long, CUI Jian-jun, LIN Ge 2004, 25 (1):  125-127.  Abstract ( 72 )   Save This paper highlights the reservoir sand body, petrology, pore structure, petrophysical properties and their effects in Yanan delta by way of macroscopic and microscopic study, including thin-section and cast thin-section analysis data, etc. Inte-grating with petroleum exploratory progress of the delta, this paper proposes statistically that Chang-4+5, Chang-6' and Chang-6?oil layers in target area are better than other layers. In general, the microfacies-developed zone of distributary channel in thedelta front is the most favorable for hydrocarbon prospecting.In spite of belonging to low porosity and low permeability reservoirwith compaction and dominated by intergranular dissolved pores and intergranular residual porosity, Yan'an delta still has greaterpotentials for petroleum development compared with the similar domestic fields. References | Related Articles | Metrics

Restoration of Eocene Erosion Thickness in Gaoyou Sag LIU Xiao-ping, YANG Li-gan, XU Jian 2004, 25 (1):  128-130.  Abstract ( 89 )   Save The tectonic subsidence of Subei basin ceased during Sanduo movement from Late Eocene to Oligocene. It had broughtabout the end of faulting growth in it and depositional break for 18Ma, with strong uplifting,erosion and absence of UpperEocene and Oligocene. The imbalanced erosion of Gaoyou sag is analyzed by the data of homogeneous temperature, clay mineral,vitrinite reflectance and C29-20S/(20S+20R) sterane ratio. It is shown that the erosion becomes stronger gradually from deep sagzone to slope zone,fault terrace zone and low uplift. The erosion thickness is estimated by the method of interval transit timeand forward numerical simulation of vitrinite reflectance. The results of them coincide with each other. The total erosion thicknessis about 400~1 600 m, where deep sag zone is of 400~600 m, slope zone of 500~1 200 m, fault terrace zone and low uplift of1 000~1 600 m in total. Such estimated values are bigger than previous results of qualitative estimation, which mean that renewalstudies should be made in the burial history, geothermal history, hydrocarbon accumulation history and oil-gas reservoir distributionn Gaoyou sag. References | Related Articles | Metrics

The Differential Hydrocarbon Accumulation in Long-Axis Anticline of Honggang Field,Songliao Basin CHEN Guo-li 2004, 25 (1):  131-133.  Abstract ( 82 )   Save The regular distribution of oil, gas and water due to gravitational differentiation tends to the fact that a gas reservoirforms in structural trap at higher part, while an oil reservoir in structural trap at lower part. However, there exist gas reservoir intrap at lower part and oil reservoir in trap at higher part due to differential hydrocarbon accumulation. Many typical cases haveindicated this abroad.In long-axis anticline of Honggang field in Songliao basin, it is indicated from formation tests that Hong-l31 trap belongs to a gas reservoir which lies in lower sub-layer G13 of Gaotaizi sand layer-II, Hong-7 trap is an oil-gas reser-voir at higher part, and in Hong-l6 trap merely contains water which lies at the top. Based on detailed analyses of the structuraland reservoir characteristics, it is shown that the basic conditions for differential hydrocarbon accumulation could appear in layerGl3 and can be used for well interpreting its oil-gas distribution. So the sub-layer G13 is found to be as a first and typical caseof the differential hydrocarbon accumulation in China. References | Related Articles | Metrics

Evaluation on Vertical Sealing Nature of Main Faults in Chegu-20 Burried Hill FU Guang, FU Xiao-fei, MENG Qing-fen 2004, 25 (1):  134-136.  Abstract ( 75 )   Save The faults development and evolution features in Chegu-20 burried hill as well as their vertical sealing mechanisms andaffected factors are analyzed. The main factors controlling vertical sealing faults are the pressure exerted on fault plane and theshale content. From the modeling result of compressive experiment,the plastically deformed limitation of mudstone is presented,and the method for prediction of sandy and shale contents in fault zone is established by its lithology and fault throw.Based onthese, the vertical sealing nature of Chegu-20 burried hill in Carboniferous-Permian to Paleogene are evaluated. It is pointed outthat the faults are all characterized by vertical sealing nature in C-P to Es* except for faults F3, F42 and F? in Line-298 and a-long Chegu-203-Chegu-20-Chegu-201. They show that this area possesses significant conditions for hydrocarbon accumulation andpreservation. References | Related Articles | Metrics

The Hydrocarbon Accumulation Model of Middle Segment in Dongbu (Eastern) Sag of Liaohe Basin JIANG Jian-qun, ZHANG Zhan-wen, ZHANG Fu-gong, LI Ming-kui 2004, 25 (1):  137-140.  Abstract ( 80 )   Save The complex faulting system and abnormally active volcanic process make the middle segment of Dongbu sag in Liaohebasin possess unique hydrocarbon accumulation model.Establishment of such a model is based on relationship between the vol-canic process and hydrocarbons in it and the analysis of reservoir rocks and spatial distribution.Study shows that Sha-3 layer of Oulituoz area is rich in petroleum due to premiere assemblages among enough oil sources, fair transport system and fine energyconfiguration. The petroleum accumulation model is characterized by vertical migration assisted with lateral short-distance migration.But in Tiejianglu area, petroleum migration and accumulation are different from those in Oilituoz area,its channel media forpetroleum migration are dominated by interconnected sands with little vertical migration along the faults,thus resulting in petroleum distribution primarily in the middle-lower section of Sha-3 layer. References | Related Articles | Metrics

Analysis of Structural Model of Gumudi Anticline in Southern Margin of Junggar Basin LI Xue-yi, LIU Lou-junl, CHEN Wei 2004, 25 (1):  141-142.  Abstract ( 53 )   Save The southern margin of Junggar basin underwent Tianshan movement in late Himalayan orogeny and formed a series ofanticlines and related faults. Owing to its complex surface and subsurface geologic conditions, the seismic reflection data from thisarea are poor and the structural style varies and is always troublesome in discrimination.In order to establish the properstructural style, this paper takes the structural description of Gumudi anticline as an example, the fault-folded theory as a guide,and the structural modeling technique as a tool for anatomizing complex structures, finally, develops a model of structural geologyfitting for real situation of this area. The procedure for modeling is also presented herein. References | Related Articles | Metrics

Hydrocarbon Conduit Systems and Migration-Accumulation Model in Tahe Oilfield CHEN Qiang-lu, HUANG Ji-wen 2004, 25 (1):  143-146.  Abstract ( 80 )   Save Tahe oilfield in Tarim basin is characterized by multi-stage hydrocarbon generation, multi-channelmigration and multi-stage petroleum accumulation.This paper discusses the hydrocarbon conduit systems such as fault and structural fissure,unconformity and paleo-weathering crust, Ordovician vug and fracture as well as interconnected sand body in light of Tahe oilfieldand its regional geological situations.The study shows that it is these systems that control the hydrocarbon migration andaccumulation in different periods and reservoirs,the formation and evolution of different areas and types of pools. The systemscan be classified with network-like model and zigzag-like model for petroleum migration and accumulation. References | Related Articles | Metrics

The Tectonic Evolution in Hetian Paleohigh and Its Petroleum Distribution SUN Wei, LIU Shu-gen, XU Guo-qiang, LI Guo-rong 2004, 25 (1):  147-149.  Abstract ( 102 )   Save The paleohigh is the center of long-term hydrocarbon migration and accumulation, and also one of the major domainsfor further exploration of west-central China. Hetian paleohigh in Tarim basin is a paleohigh with deposition and denudation.Itsformation and evolution which have greatly affected the hydrocarbon generation,migration,accumulation and preservation in thestudied area can be divided into three stages: 1) uplifted and denudated stage in Caledonian movement,2) buried stage inHercynian movement, and 3) destructed stage in Himalayan movement. And it became a slope at last following these processes. Itwas the existence of Hetian paleohigh that hydrocarbon generation, adjustment, migration and trap formation in it were in optimalmatched conditions. The evolution of it has a profound geological significance for the source rock development and hydrocarbonaccumulation in this area. References | Related Articles | Metrics

Improved Genetic Algorithm for Wave Impedance Inversion LI Jing, CHEN Yu-ming, WANG Zhen-guo 2004, 25 (1):  150-152.  Abstract ( 86 )   Save Improved genetic algorithm takes improving on traditional genetic algorithm for practical question of seismic wave impedance inversion, based on the best choice and evolutional principle in natural biology genetic process. This algorithm takesquinary system coding instead of binary system coding before introducing Boltzmann exist mechanism in genetic operation,and can be used for inversion of seismic wave impedance so that allows object function to meet an order as required and allows nonlinear method of annealing genetic algorithm to be applied in the inversion of seismic wave impedance. References | Related Articles | Metrics

Application of Seismic Attributes in Prediction of Dolomite in Biyang Sag JIN Ling, DING Yan-hong, SU Gui-zhi, ZHANG Yu-xia 2004, 25 (1):  153-155.  Abstract ( 87 )   Save (Research Institute of Exploration and Development, Henan Oilfield Company, Sinopec, Nanyang, Henan 473132, China) References | Related Articles | Metrics

Difficulties and M easures for Development of Low Permeability Tight Gas Reservoirs and Condensate Gas Reservoirs LI Shi-lun, SUN lei, DU Jian-fen, TANG yong, ZHOU Shou-xin, GUO ping, LIU Jian-yi 2004, 25 (1):  156-159.  Abstract ( 86 )   Save Low permeability tight gas reservoirs and condensate gas reservoirs account for a rather high proportion of domestic gas re-serves, but many of them have low productivity. So it is significant to develop these reservoirs efficiently for continuous and stabledevelopment of China's petroleum industry. Around the problems of the development of deep low permeability tight gas reservoirs andcondensate gas reservoirs,this paper makes an analysis on the geologic and development characteristics of these reservoirs and pre-sents ten proper technologies.Finally,five technical measures for the development of such gas reservoirs are proposed in detail.These are deep fracturing technology, treatment technology of accumulated liquids in condensate gas well and near well bore, gas in-jection technology when the formation pressure is lower than the maximum condensatepressure, phase behavior analysis technologyn porous media of low permeability tight condensate gas reservoir and other gas reservoir engineering technologies. References | Related Articles | Metrics

A Decomposition Method of Skin Factor for Gas Well CHEN Y uan-qian 2004, 25 (1):  160-164.  Abstract ( 113 )   Save Skin factor of near wellbore zone is an important parameter to evaluate productivity and completion efficiency of oiland gas wells. However, the skin factor determined by pressure buildup curve of gas well is a total skin factor which includespenetration degree skin factor, perforation density skin factor, high velocity turbulence skin factor and mud damaged skin factor.Based on concerned references [1-6], a decomposition method of the skin factor of gas well is proposed in this paper. Theeffectivity of the method is indicated by case applications. References | Related Articles | Metrics

A Mathematic Model for Non-Darcy Flow at High Flow Rate ZHANG Lie-hui, ZHU Shui-qiao, WANG Kun, ZHOU Lin 2004, 25 (1):  165-167.  Abstract ( 164 )   Save Forchheimer's Equation,a classical equation put forward by Forchheimer in 1901,has been used for offset the deficiency of Darcy's law at high flow rate by way of adding a non-Darcy term into Darcy's law.This term is a product among the non-Darcy coefficient, the fluid density and the square of flow velocity. To estimate the non-Darcy coefficient as accurately aspossible is one of the most important aspect for determination of non-Darcy effects. This paper establishes a new fully implicit 3-D gas reservoir mathematic model with multiple types of reservoirs and scopes of permeability based on study of a great numberof literatures and analysis of mathematic descriptions of various non-Darcy effects.In this model, the non-Darcy effect of gas athigh flow rate can be more effectively concerned about. In addition, using OrthoMin method to solve the algebraic equation seriesis quick in speed and reliable in stability. References | Related Articles | Metrics

Creation of Component Adsorption Isothermal Curve for Porous Media of Gas Reservoir MEI Hai-yan, ZHANG Mao-lin, DU Zhi-min, LI Min, SUN Liang-tian 2004, 25 (1):  168-171.  Abstract ( 73 )   Save For the different adsorbates in the same adsorbent (porous media), the adsorption powers measured under the differenttemperatures are correlated with the adsorption potentials. The relative regression equations are given by matching the experimentaladsorption data from adsorption potential theory and definition of Dubinin adsorption potential. The regression equation can be usedto determine the average petrophysical parameters for a gas reservoir (Case 2)and create the adsorption isothermal curves forvarious components under given gas-layer temperature in it. It provides significant basic data and research methods such asadsorption phase equilibrium simulation and oil-gas reservoir numerical simulation for study of adsorption processes in porous media. References | Related Articles | Metrics

A dsorption Equilibrium Model and Its Verification of Gas Mixture ZHANG Mao-lin, MEI Hai-yan, DU Zhi-min, LI Min, SUN Liang-tian 2004, 25 (1):  172-176.  Abstract ( 66 )   Save Gas mixture adsorption is related to temperature and pressure, also there exists the competing adsorption phenomenawith the change of gas composition.The gas mixture adsorption model can be used to calculate the adsorption equilibriumquantity of each component of the gas mixture at certain temperature and pressure by using pure component or bi-component gasadsorption isotherm. The two-phase equilibrium calculation model with the adsorption phase and freedom gas phase is developed .using Flory Hugging Vacancy Solution Model(FHVSM)of gas adsorption.For two samples of dual gas mixture adsorptionequilibrium, the adsorption equilibrium simulation calculation is completed after regressing the parameters of the pure componentadsorption isotherm. The studied result shows that FHVSM can be used to describe the gas mixture adsorption equilibrium andsimulation calculations of adsorption equilibrium for both hydrocarbon gas mixture and non-hydrocarbon gas mixture. References | Related Articles | Metrics

Buildup Test Analysis of Condensate Gas Well Considering Adsorption Effect HUANG Quan-hua, LI Shi-lun, SUN Lei, XU Shi-guo 2004, 25 (1):  177-179.  Abstract ( 86 )   Save n regard to present well test interpretation for gas condensate well, single phase pseudo-pressure method for dry gaswell is still be used in general, of which the effect of porous media on adsorption of condensate oil and gas is not considered.But more and more experiments and theoretical studies indicate that porous media adsorption is of greater influences on thepercolation of condensate oil and gas.This paper proposes the method for buildup test analysis of condensate gas wellconsidering adsorption effect based on differential equation of percolation with adsorption effect of condensate gas well and draw-down test analysis.Case study shows that the effect of porous media adsorption could result in decreasing effective permeability,increasing skin factor,reducing detection radius of gas well in well test interpretation. For a condensate gas reservoir with highheavy hydrocarbon content and low porosity, the influence of porous media adsorption would be much more apparent. Hence, theinfluence of porous media interfacial phenomena on the percolation and well test in a condensate gas well can not be neglected. References | Related Articles | Metrics

Study on Numerical Simulation of Hutubihe R eservoir in Luliang Oilfield ZHANG Ji, ZHANG Lie-hui, ZHANG Hong-mei, JIANG Xiao-hu, ZHANG Ju-zeng 2004, 25 (1):  180-181.  Abstract ( 74 )   Save Hutubihe reservoir(K]h26~Kph2) of Wellblock Lu-9 in Luliang oilfield of Junggar basin is an edge-water reservoircharacterized by low amplitude structure, complicated oil-water relationship and intensive heterogeneity. Applying numerical simulationmethod,integrated with results of detailed reservoir description and reservoir engineering study,this paper presents technicallimitations of rational development of Hutubihe reservoir and determines that waterflooding process and inverse 9-spot pattern shouldbe adopted with the cut-offs such as rational production rate of 2.9%, reasonable injection-withdrawal ratio of 0.8, sound pressurelevel of 9.0MPa. It is indicated that these numerical simulation results are helpful to Luliang oilfield for high effective development. References | Related Articles | Metrics

Feasibility Study of CO, Injection for Heavy Oil Reservoir after Cyclic Steam Stimulation LUO Rui-lan, CHENG Lin-song 2004, 25 (1):  182-184.  Abstract ( 91 )   Save In accordance with the fact that many domestic heavy oil reservoirs or blocks have entered into their late stage ofcyclic steam stimulation and hence the development effects are getting worse, feasibility of CO2 injection for different viscosities ofheavy oil reservoirs following steam stimulation is studied using methods of numerical simulation and reservoir engineering andtaking Lengjiabao heavy oil field in Liaohe etc. as samples. And the results from the simulation and field pilot test are evaluatedeconomically. Study shows that for common heavy oil after cyclic steam stimulation, the higher the oil viscosity, the greater theutilization factor of CO, injection, and the more feasible by CO, stimulation process; for extra and super heavy oil, one to threesteam stimulations at least are performed as necessaryfollowed by converting it into CO, stimulation process so that good benefitcould be gained. These results are of significance for field operation and production of heavy oils. References | Related Articles | Metrics

An Optimized Model for Oil Development Programming/ Decision Support System JIANG Hou-shun, LIU Ce, YE Yi-ping 2004, 25 (1):  185-187.  Abstract ( 95 )   Save The oil development programming/ decision support system (ODPDSS) is a systematic engineering featured by extensiveknowledge and complicated contents in design.And reasonable usage and distribution of resources is the key of its run ofdecision-making.This paper proposes the single-object linear programming model which is a distribution method for resourceoptimization based on certain production rate and low cost and the multi-object linear programming model which is a distributionone for highest production rate and lowest cost.These two models can be used for dealing with fully exerting potentials of anoilfield under the factor control of decision-making and for the purpose of achieving optimal production of it. References | Related Articles | Metrics

Suitability Study of Nitrogen-Foam Flood in Heavy Oil Reservoir An example of L iaohe oilfield YANG Guang-lu, LIN Yu-qiu, LIU Jia-lin, BAO Jun-gang 2004, 25 (1):  188-190.  Abstract ( 99 )   Save Up to now, most of heavy oil reservoirs in Liaohe oilfield have undergone steam stimulation development, some of themwith lower crude viscosity have undergone processes from transitory conventional recovery into waterflooding. However, most of theheavy oil reservoirs follow ing steam stimulation recovery appear in obvious inconsistency in vertical and horizontal producingperformance due to their serious heterogeneities.Moreover,with precipitous pressure decline and degassed crude viscositydecrease, the development effectiveness has been distinctly getting poorer. Therefore, converting available development process ofthis type of reservoirs is the most urgent situation. This paper presents the studies of the mechanism of nitrogen-foam flood forEOR,and suggests that the mechanism of nitrogen-foam flood used to regulating injection profile is proper to improve thedevelopment effectiveness of these reservoirs.In view of few tests of large-scale nitrogen-foam flood at home and abroad,suitability research of such a flood is systematically performed using numerical and physical simulation approaches.Finally, sixheavy oil blocks in Liaohe oilfield are selected to be as field operation ones based on the reservoir conditions suitable fornitrogen-foam flood given in this paper. References | Related Articles | Metrics

Usher Model for Water Cut Prediction in W aterflood Field ZHANG Ju-zeng, ZHANG Lie-hui, ZHANG Hong-mei, PENG Yong-can 2004, 25 (1):  191-192.  Abstract ( 112 )   Save It is significant for predicting watercut vs time in a waterflood field. Usher model, a model for general prediction ofpetroleum economy and resources, is used to predict watercut based on the increasing watercut in waterfood field.By analysis,this paper points out that available Logistic model and Gompertz model are the specific ones of Usher model.And field application indicates the practicality and validity of Usher model. References | Related Articles | Metrics

Estimation of Economic Recoverable Index for High Watercut Stage in Karamay Conglomerate Reservoir CHEN Yu-chuan, SHI Jun, WANG Xiang-dong, DONG Guang-hua, CHEN Xu-hua 2004, 25 (1):  193-195.  Abstract ( 82 )   Save This paper presents three methods for estimation of economic recoverable reserve, surplus economic recoverable reserveand economic recovery factor, i.e. watercut vs cumulative oil production curve, waterflood type curve and monthly oil productionvs time curve, which are based on the characteristics of Karamay high watercut conglomerate reservoir and domestic policy ofpresent finance and taxation.The typical case estimation shows that these methods are effective and feasible for obtaining aboveindices. References | Related Articles | Metrics

Realization of Integrated Technology of Reservoir Description with Numerical Simulation ZHANG Huiyong WU Xiaojun Abduresiti Turson, XU Changfu WU Xuquan, QIN Jun, KONG Chuixian 2004, 25 (1):  196-198.  Abstract ( 80 )   Save Taking Wutonggou reservoir in Shanan oilfield as an example,1 method for realization of integrated technology ofreservoir description with numerical simulation is expounded. .Firstly, the 3-D geologic model is developed by using reservoirdescription technology, based on integrated analysis of the mode uncertainties,selecting a suitable geologic model for actualreservoir as input data of numerical simulation. Secondly, the reservoir numerical simulation model is developed by using griddingtechnology integrated with production performance.Finally, the reasonable technical limit for reservoir recovery is proposed byindex prediction and effectiveness evaluation based on the history match and different recoveryprocesses affecting reservoirdevelopment efficiency.Applying the integrated technology of reservoir description with numerical simulation can improve theaccuracy and quality of geologic model during numerical simulation, and provide reliable technical guarantees for the optimizationof development process and the in-depth study of remained oil distribution. References | Related Articles | Metrics

Determination of Perforation Intervals of Wells in Bottom-Water Reservoirs with Barriers LI Chuan-liang 2004, 25 (1):  199-201.  Abstract ( 59 )   Save Determination of perforation intervals and optimal shot density of wells in bottom-water reservoirs with barriers isstudied and presented. The study shows that barriers with both high critical rates and high production rates existed in bottom-water reservoirs are generally protected or retained, while those with high critical rates and low production rates or low criticalrates and high production rates should be perforated.The wells perforated by distribution of the barriers appear in higherproduction rates and postpone the breakthrough time of bottom-water on a large scale. Bottom-water reservoirs with barriers displayabundant natural drive energy in development and overcome the drawbacks of short water-free oil production period in bottom-water reservoirs without barriers. References | Related Articles | Metrics

Determination of Displacement Efficiency and V olumetric Sweep Efficiency XIANG Tian-zhang, LI Lu-bin 2004, 25 (1):  202-203.  Abstract ( 131 )   Save In accordance with one dimensional waterflood theory of Buckley-Leverett,mathematical relationship between oildisplacement efficiency and recovery percent of recoverable reserves as well as minimum value of displacement efficiency arederived. And the numerical model of this relationship from a case of Liaohe field is developed accordingly. In addition, using therelationship among recovery percent,displacement and volumetric sweep efficiency, the equations for estimation of the volumetricsweep efficiency and the recovery percent of recoverable reserves are obtained, based on which the volumetric sweep efficiencyand the potential analysis of displacement efficiency in late stage of waterflooding along with development regime to be adoptedare proposed. The actual application is identical to the calculated results. References | Related Articles | Metrics

Model Database of Low-Velocity Layer in Surface of Tabei Area, Tarim Basin GU Jun-lun, LI Hong, CAO Li 2004, 25 (1):  204-205.  Abstract ( 81 )   Save In 2-D seismic data processing, to control the discrepancy in closing of static correction parameters tends to improvethe discrepancy in closing of seismic profile.Through establishing a database of surface low-velocity layer of Tabei area in Tarimbasin, coordinating data from 2-D and 3-D low-velocity layer, searching and eliminating singular values, and then inputting them .into the database, this paper develops a model of surface low-velocity layer that can be used steadily and repeatedly, by whichobtains the gridding low-velocity layer data generated after smoothing and interpolation using uniform calculation method.Usingsuch a model database can not only shorten the data processing cycle, but also improve the discrepancy in closing of seismicprofile fleetly and reliably. References | Related Articles | Metrics

The Study and Practice of Condensate Gas Reservoir Converted into Underground Gas Storage YANG Shu-he, TIAN Jin-hai, LI Bao-rong, YANG Bo, ZHU Xiao-li 2004, 25 (1):  206-208.  Abstract ( 78 )   Save The underground gas storage plays an important role in adjusting contradiction of supply and demand of natural gas inwinter and summer, ensuring the requirement of consumers and optimizing the function of gathering and transferring system.Theconstruction of such an underground gas storage abroad has hundred of years history,but it is just in initial phase in China.Along with the implementations of north Shaanxi's natural gas transferred toward Beijing and the Blue Sky project in Beijing, theguarantee of the use of natural gas of Beijing has become the premier issue of natural gas supplier. On the basis of explanationof concept and theory of undergroun gas storage, the chief conditions as necessary for construction of the underground gas storageare provided. Through the analysis of investigation results of concerned stuffs or data at home and abroad, the geology-selectedrules for construction of underground gas storage have been summed up. At the same time, taking the construction project ofunderground gas storage of the condensate gas reservoir in Dagang oilfield as example, the design gist, theory and running projectoptimization are presented. References | Related Articles | Metrics

On Gas Accumulation and Preservation FU Xiao-yue 2004, 25 (1):  212-214.  Abstract ( 218 )   Save Natural gas accumulation is a process of dynamic balance between gas accumulation and gas fugitive emission, in which the inflow and preservation of gas are the key factors for gas reservoir.The preservation of gas-bearing basin primarily depends on its cap rock, late tectonic movement, forming time of gas reservoir, gas supply area and intensity. Normally, a largegas field has its hydrocarbon-generating intensity of over 20x108 m3/km2. The study shows that from the whole to the local, usingmultiple methods and parameters for systematic analysis is a foundation of proper hold and understanding of petroleum prospectsin an area. This paper stresses the effect of pressure seal on gas accumulation and preservation. The pressure system can be asan important index for discrimination of whether a gas-bearing basin possesses sealing and preservation conditions on the whole ornot. References | Related Articles | Metrics

Aryl-Isoprenoids in Crude Oil and Its Implication in Geological Exploration Aryl-Isoprenoids in Crude Oil and Its Implication in Geological Exploration 2004, 25 (1):  215-218.  Abstract ( 62 )   Save Investigations of aryl-isoprenoids in sedimentary organic matter suggest that these compounds are the diagenetic productsof certain precursors from photosynthetic green sulphur bacteria Chlorobiaceae,indicating that its source rock was formed in anintense reductive environment.Marine oils from the tableland-basin region in Tarim basin generally contain abundant aryl-isoprenoids with the carbon number range of C]o~C23 The pyrolytic products of the bitumen fraction in the oils are also characterized by a typical sulphur bacteria origin,i.e.,an abnormal enrichment of tetra-methyl benezenes in the C2~C5 alkylbenzene fraction. These data indicate that the major marine oil and gas were originated at least from one set of the importantsource rocks developed in a water-layered anaerobic sedimentary environment in the tableland-basin region of Tarim basin,iraddition to the consensus that they were derived from the Upper-Mid Ordovician sedimentary rocks with clay -mottar dome faciescontrolled by the upwelling ocean current in an incline at the platform margin. References | Related Articles | Metrics

Some Disputable Issues about Petroleum Geology I. M. Shahnovsky 2004, 25 (1):  219-224.  Abstract ( 76 )   Save According to petroleum organic origin theory, the original materials for hydrocarbon generation are the dispersed organicmatters in rocks. But a great amount of actual data indicate that the dispersed organic matters in rocks are not entered into theprocess of hydrocarbon generation, and conditions required for extracting organic matters from powder rock samples in a lab arenot existed in nature. In contrary, there exist inexhaustible free hydrogen and volatile carbonide in deep crust, which may reacteach other under high temperature and high pressure in mantle source,forming hydrocarbon accumulations provided withhydrocarbon fluid such as oil field,gas field,bitumen deposit and combustible shale. They could all be generated by deepinorganic fluid in Neogene.n addition, this paper presents an idea of coal can be formed by deep hydrothermal fluid as thesame as crude oil.During the process of petroleum generation and accumulation caused from mantle hydrothermal fluid,discordogenic fault or transport faulting broken to the mantle would play the most significant part. Related Articles | Metrics

Difficulties andM easuresfor Development ofLow Permeability TightGas R eservoirs and Condensate Gas. R eservoirs LI Shi-lun, SUN lei, DU Jian-fen, TANG yong, ZHOU Shou-xin, GUO ping, LIU Jian-yi 2004, 25 (1):  225-230.  Abstract ( 74 )   Save Low permeability tight gas reservoirs and condensate gas reservoirs account for a rather high proportion odomestic gas reserves, but many of them have low productivity. So it is significant to develop these reservoirs effi-ciently for continuous and stable development of China's petroleum industry. Around the problems of the developmentof deep low permeability tight gas reservoirs and condensate gas reservoirs, this paper makes an analysis on the geo-logic and development characteristics of these reservoirs and presents ten proper technologies. Finally, five technicalmeasures for the development of such gas reservoirs are proposed in detail. These are deep fracturing technology,treatment technology of accumulated liquids in condensate gas well and near well bore, gas injection technology whenthe formation pressure is lower than the maximum condensatepressure, phase behavior analysis technology in porousmedia of low permeability tight condensate gas reservoir and other gas reservoir engineering technologies. References | Related Articles | Metrics