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01 April 1998, Volume 19 Issue 2 Previous Issue    Next Issue

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HYDROCARBON GENERATION AND EVOLUTION IN TARIM AND JUNGGAR BASINS Zhang Jinglian, Zhu Bingquan, Tu Xianglin, Zhang Pingzhong 1998, 19 (2):  95-100.  Abstract ( 221 )   PDF (286KB) ( 239 )   Save Based on lead, strontium and neodymium isotopes data in kerogen and bitumen in Tarim and Junggar basins, this paper discussed four problems that have to be answered by petroleum geologists:① what to generate hydrocarbon, ② how to generate hydrocarbon, ③when did hydrocarbon generate, and ④when did hydrocarbon migrate, and pointed out that hydrocarbons in Tarim and Junggar basins generated in different tectonic background, hydrocarbon generation model, time and migration time were different, but their generation complied with inorganic synthetic reaction process proposed by Fisher and Tropsch.The author considers that controls of geochemical steep belt on distribution of oilfield are very obvious, hence geochemical steep belt(deep source crust-mantle interaction belt)should be regarded as target areas for finding large- and ultralarge-scale oil/gas fields.Northern, southwestern and northeastern areas in Tarim basin, as well as basement in Junggar basin should be favourable area for finding large-scale oil/gas fields. References | Related Articles | Metrics

THE UNCONFORMITY TYPES AND THEIR RELATIONS WITH OIL/GAS RESERVOIRS IN TARIM BASIN Wu Yajun, Zhang Shouan, Ai Huaguo 1998, 19 (2):  101-105.  Abstract ( 167 )   PDF (269KB) ( 222 )   Save Tarim basin has undergone multi-stage tectonic movements, and formed three types composed of six subtypes unconformities. These unconformities were better passages for hydrocarbon migration and favourable places for its accumulation, which were of strong effect of transform action of underlying reservoir quality, but also of destructive effect on early formed reservoirs. In addition, they are favourable for late reservoir-formation because of their reconfining actions.It was the difference, inheritance and migration of unconformity types that controlled the formation, evolution and distribution of petroleum reservoirs. Fault-folded and fold unconformities are the most favourable controlling-oil ones. References | Related Articles | Metrics

OIL/GAS DISTRIBUTION CHARACTERISTICS AND EXPLORATION STRATEGY IN TURPAN-HAMI BASIN YuanMingsheng 1998, 19 (2):  106-111.  Abstract ( 147 )   PDF (292KB) ( 200 )   Save After major breakthroughs in exploration in Jurassic of Tabei sag in Turpan-Hami basin, and discovery of a lot of coal-formed hydrocarbon oil/ gas fields, heavy oilfields with multiple series and types combined hydrocarbon-bearing were found in Triassic of Tainan sag.Based on analyses of formation and evolution of Turpan-Hami basin, this paper discussed oil/gas geologic condi tion and accumulating regulari ty of three major petroliferous systems (J-K, P-T, C)and four major hydrocarbon accumulating units (Tainan, Taibei, Tuokexun and Hami), and evaluated resource potential, presented exploration strategy of following scientific exploration program and realizing continuous increase of oil and gas reserves. References | Related Articles | Metrics

DIAGENESIS AND PORE CHARACTERISTICS OF CARBONATE ROCK UNDER UNCONFORMITY IN TARIM BASIN Ai Huaguo, Lan Linying, Zhang Keyin 1998, 19 (2):  112-120.  Abstract ( 153 )   PDF (367KB) ( 377 )   Save Studies on diagenesis, sedimentary sequence and pore characteristics of carbonate rock under unconformable surface in Tarim basin showed that:①carbonate reservoir under unconformable surface underwent cementation, denudation, dolomitization, recrystallization, compaction, solution, silicification, filling of siliceous cement and fracture, among which cementation, compaction, silicification and filling of siliceous cement were major diagenesis for destroying pores;denudation(especially air water when unconformi ty formed), dolomitization, solution and fracturing were major diagenesis for forming secondary pores.② The pores in carbonate reservoir under unconformable surface during hydrocarbon migrating were all to be secondary, among which intercrystalline pore, intercrystalline denudation pore, cement denudation pore, matrix denudation, vugular pore, denudation fracture and stylolite were main pore types, with pore diameter of 0.01~ 1 mm and vugular pore diameter of 2~ 10 mm, the porosity of 2%~ 8%, larger than 15% in local area. References | Related Articles | Metrics

DISTRIBUTIONOF FORMATION PRESSURE AND THE RELATIONWITH HYDROCARBON IN NORTHERN TARIM BASIN WangMeiling, Ye Desheng 1998, 19 (2):  121-125.  Abstract ( 118 )   PDF (235KB) ( 198 )   Save On the basis of measured formation pressure by drilling, the relation of interval transit time and depth as well as formation pressure calculated from seismic profile, this paper analyzed distribution characteristics of formation pressure in vertical and lateral directions, suggested that there are two abnormal high pressure belts in seismic profile including Suweiyi formatiom-Silurian and Lower Cambrian-Sinian, and obvious pressure anomaly occurred in Carboniferous in Akekule area, which could form confining pressure zone, being very favourable for preservation of late-stage-formed reservoirs under underlying strata. References | Related Articles | Metrics

ORIGIN CLASSIFICATIONOF CARBON AND HYDROGEN ISOTOPES AND THEIR DISTRIBUTION REGULAR IN TARIM BASIN Fan Guanghua, Xiao Zhongrao 1998, 19 (2):  126-131.  Abstract ( 141 )   PDF (254KB) ( 201 )   Save According to component characteristics of carbon and hydrogen isotopes, natural gas in Tarim basin can be classified into continental facies, marine facies and miscible one.Marine facies gas distributed in south and north sides of Mangar Paleozoic marine source sag, Tazhong uplift and south of Tabei uplift;continental facies gas in Kuqa Mesozoic source sag and north of Tabei uplift;marine and continental conbination gas in Yakela structure, some wells in Donghetang and Well Qun 5 in Bashituopu anticline in Tazhong uplift.Gas from Kekeya anticline are dominented by continental coal-formed gas possibly filled wi th marine hydrocarbon. References | Related Articles | Metrics

GEOLOGIC FACTORS OF CONTROLLING GAS AND PROSPECTIVE POTENTIAL IN JUNGGAR BASIN Wang Yutao, Chen Xin 1998, 19 (2):  132-136.  Abstract ( 107 )   PDF (253KB) ( 241 )   Save In recent years, major breakthroughs were made for natural gas exploration in Junggar basin, larger scale of gas reservoi rs were successively found in south margin, east part and northwest margin, indicating the enormous potential for natural gas exploration.Based on these results, this paper studied and discussed the macro regularity of distribution and enrichment of natural gas in Junggar basin, pointing out that ① large and medium scale of gas fields are distributed in special area in plane;② distribution of natural gas is obviously controlled by gas-bearing sytem;③ humus and high mature area are major factors for controlling formation and enrichment of gas;④ better assemblages of effective gas source and best regional caprock are important conditions for finding large and medium scale of gas fields;⑤ deeper part in Junggar basin is major place for forming these gas fields.Addi tionally, primary exploration areas are suggested, several proposals for gas exploration in future are presented. References | Related Articles | Metrics

TYPES OF CLAY MINERALS IN TARIM BASIN Zhao Xingyuan 1998, 19 (2):  137-144.  Abstract ( 200 )   PDF (329KB) ( 221 )   Save Eleven analyses including X-ray diffraction etc.were made, eleven types of clay minerals were determined in Tarim basin, in which dickite, corrensite and playgorskite are special minerals.This paper emphasized major mineralogy characteristics of dickite, corrensite and playgorskite. References | Related Articles | Metrics

FILL SEQUENCE AND ITS PETROLEUM GEOLOGY SIGNIFICANCE IN SECONDARY SAG IN TANGYUAN FAULT-DEPRESSION Luo Qun, Bai Xinhua, Liu Xiaodong 1998, 19 (2):  145-149.  Abstract ( 119 )   PDF (199KB) ( 228 )   Save Hydrocarbon generation potential of source sag controls oil/gas prospecting potential in a petroliferous basin.There was very close relation between feature of sag and fill sequence.Eight secondary sags were developed in Tangyuan depression, among which the difference between basement feature and its controlling on fault movement resulted in different types of sedimentation and fill characteristics.Based on analyses of formation and evolution regularity and formation fill sequence of each secondary sag in Tangyuan depression, this paper summerized three models for secondary sag and fill sequence.On the basis of analyses of development of source rock and source-reservoir-cap assemblage characteristics, oil/gas prospective potentials of different types of sag were predicted. References | Related Articles | Metrics

ARPS DECLINE OF WATERFLOODING OILFIELDS Yu Qitai, Chen Suzhen, Li Wenxing 1998, 19 (2):  150-153.  Abstract ( 85 )   PDF (197KB) ( 310 )   Save Distribution of Arps decline parameters and its effect factors of oilfields were summarized.In terms of analyses and research of references at home and abroad, a method for calculating Arps hyperbolic decline parameters has been screened, which is more reasonable, more simple and clear and much easier to use.By using this method, the data from 75 domestic waterflooding sandstone oilfields and 10 bottom water limestone oilfields, and 17 waterflooding sandstone oilfields in the Soviet Union have been handled, corresponding Qi, n and Di have been calculated and the histograms about n and Di distribution on oilfield's number have been made.The conclusions have been drawn from the histograms: ①waterflooding oilfields followed Arps decline, Oilfield's number of 0 <n <1 took 85%~ 90 %;②when n got larger gradually, ratio of oilfield's number changes from large to small;③ n >0.1 could appear for waterflooding oilfields at home and abroad, its oilfield's number took 10 %~ 15% in total;④ during oilfield development after presence of declinine, n is a variable;⑤Di is mainly distributed in 0.1<Di <0.3 sections for waterflooding sandstone oilfields and in Di >0.4 sections for bottom water limestone oilfields. References | Related Articles | Metrics

PHYSICAL SIMULATION FOR FORMATION AND DISTRIBUTION OF FINGERING AND REMAININGOIL Zhu Jiucheng, Lang Zaoxin, Huang Yanzhang 1998, 19 (2):  154-158.  Abstract ( 100 )   PDF (264KB) ( 231 )   Save Water-oil displacment experiments with various viscosity and displacing rates are performed on plain percolation model.Origination of fingering and remaining oil as well as their influnce on recovery percent are analyzed.The potential of exploiting remaining oil in areas around inlets and outlets is first proposed, furthermore, the factors of production rate influnce on recovery percent, such as cri tical characteristics, backflow phenomena, self similari ty of fingering in irregular percolation field and fluctuation of oil flow at outlets are clarified.Recovery strategy for remaining oil and methods to reduce remaining oil during production are presented. References | Related Articles | Metrics

STUDY ON WELL SPACING FOR DEVELOPMENT OF YAKELA CONDENSATE GAS RESERVOIR IN TARIM BASIN Kang Zhijiang, Qiu Liwei 1998, 19 (2):  159-160.  Abstract ( 90 )   PDF (158KB) ( 163 )   Save Reasonable developing well spacing for condensate gas reservoir is usually determined by empirical value. During working out development project in Yakela condensate gas reservoir, two methods were used to determine it:①based on retrograde condensation characteristics of reservoirs, combining well spacing with oil recovery, reasonable developing well spacing of 1 200 m was determined with reservoir numerical simulation.② based on balance between gas and condensate oil price and oilfield construction and drilling cost, the least reasonable developing well spacing of 1 079 m was determined by calculating recoverable reserve of single well at economic limit.These methods are practical, simple and reliable. References | Related Articles | Metrics

CORRELATION AND ANALYSES OF WENG CYCLE AND POISSON, GAMMA DISTRIBUTION Zhang Hujun, Chen Mingqiang, Gu Fagong, Liu Zhanjun 1998, 19 (2):  161-164.  Abstract ( 114 )   PDF (183KB) ( 307 )   Save The correlation and analyses of Weng cycle and Poisson, Gamma distribution model showed that independent variable of original formula in Weng cycle model is specified time one, that is the time is 1/B of real time.The integral value of original formula with 0~+∞ of independent variable is rather 1/B of recoverable reserves than real recoverable reserve.Althrough original formula in Weng model and Poisson distribution have similar form of expression, Weng cycle and Poisson distribution are two different models because of their different independent variables;Weng cycle model accorded with mathematical principle of continuous Gamma random distribution, in which hypothesis of model parametern being positive integer is improper.Based on above-mentional studies, this paper gave simple and clear structural formula of Weng cycle model. References | Related Articles | Metrics

EARLY PREDICTION OF CONSEALED GAS IN PLACE FOR FRACTURE-VUGGY CARBONATE ROCK IN SOUTHERN SICHUAN—An Example of Early Estimation and Discussion of Gas in Place from a “Water Discharge to Yield Gas" Well Dong Rongxiang, Li Yongjie, Mao Chuanqin 1998, 19 (2):  165-168.  Abstract ( 79 )   PDF (182KB) ( 181 )   Save About estimation of gas in place for gas reservoirs as confined fracture-vuggy carbonate, some generally recognized classical formulas were available before.But prediction and estimation of consealed gas in place from water-gas producers within a fracture-vuggy carbonate trap is a new challenge in recent years, Based on material balance priciple, such formulas are deduced, a new concept of “discounted gas concentration"is presented in this paper, and pressure drawdown diagram of P/Z vs Gp for water-gas producer is established by which prediction of consealed gas in place for water producers can also be made.This technique has been verified from the case estimation of Well H16. References | Related Articles | Metrics

AMEHTOD FOR DETERMINING FRACTURE HEIGHTOF HYDRAULIC FRACTURING IN XIANG 4 SANDSTONE GAS RESERVOIR, BAJIAOCHANG GAS FIELD, SICHUAN Wu Yuexian 1998, 19 (2):  169-170.  Abstract ( 99 )   PDF (138KB) ( 176 )   Save Vertical fracture height from hydraulic fracturing is very important for calculating fracture length and width.Based on parameters for fracturing operation and well temperature logging data, empirical formula abroad was modified, and then a formula for calculating fracture height was established, which is simple and reliable and suitable for Xiang 4 gas reservoir in Bajiaochang gas field in Sichuan. References | Related Articles | Metrics

AN EFFECTIVEMETHOD FOR IDENTIFICATION OF GAS LAYER Li Hongwei 1998, 19 (2):  171-172.  Abstract ( 130 )   PDF (122KB) ( 155 )   Save In the light of difficulty in identificating gas layer during natural gas description and lower gas saturation value with conventional Archie formula, this paper presented a modified method with Archie formula, in which application of cross plot technique can effectively identify gas layer, its results accord with actual gas saturation.This method has solid theoretical basis and practical value. References | Related Articles | Metrics

APPLICATION OF PRODUCTION LOGGING TECHNOLOGY IN KARAMAY OILFIELD Liu Xinli, Peng Zhenzhong 1998, 19 (2):  173-175.  Abstract ( 64 )   PDF (151KB) ( 195 )   Save Development effectiveness is emphatically analyzed by applying data from injection and production profiles, and injection-production system is adjusted to transform oil reservoir.Based on data from production and injection profiles, stimulation measures are worked out, and oil recovery is enhanced by incremental production of Karamay oilfield.Better results are obtained by applying production well logging data. References | Related Articles | Metrics

SIGNIFICANCE OF BOUNDARY TESTING BY APPLYING ELECTRONIC PRESSURE GAUGE Wang Weijun, Bi Quanfu, Zhu Xiaoqiang 1998, 19 (2):  176-179.  Abstract ( 77 )   PDF (151KB) ( 177 )   Save Oil/gas reservoir boundary and its types may be quickly and correctly determined by applying electronic pressure gauge.Case history of several typical wells in Karamay oilfield showed that this testing technique is simple, quickly and reliable, and has wide application prospect in exploration and development of oilfields. References | Related Articles | Metrics

DISCOVERY OF DEVONIAN FISH FOSSIL IN WELL TAZHONG 45 AND AGE OF “DONGHE SANDSTONE" Liu Jingjiang 1998, 19 (2):  180-182.  Abstract ( 195 )   PDF (138KB) ( 246 )   Save Since “Donghe sandstone" had been found in Well Donghe 1 in 1990, antiarcha fossil was found in Well Cao 2 of Caohu area in 1993.Based on paleontology and stratigraphy studies in recent years, conodont and sporopollen were successively found nearby boundary of Carboniferous-Devonian, so “Donghe sandstone" is put in Devonian.Discovery of Devonian fish fossil in Well Tazhong 45 offered reliable evidence for “Donghe sandstone"belonging to Devonian in Tazhong area. Related Articles | Metrics