2003 Vol. 25, No. 1

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SEVERAL PROBLEMS ON OIL AND GAS PRESERVATION AND THEIR COMMERCIAL PROSPECTING IN MARINE SEQUENCES OF SOUTH CHINA
GUO Tong-lou, LOU Zhang-hua, MA Yong-sheng
2003, 25(1): 3-9. doi: 10.11781/sysydz200301003
Abstract:
Several problems in the study of oil and gas preservation and their commercial potential in marine sequences of South China should include as follows:(1) Areas near the ancient petroleum pools,the large and high anticlines at the edge of basins and the uplifted blocks between sags are not ideal locations for discovery of large oilfield in South China;(2) Conditions of petroleum preservation were very complicated;(3) The properties of hydrogeology could be used to evaluate the preservation condition;and (4) The sedimentation,burial history and geothermal evolution should be studied in detail,and the hydrocarbon generation,migration and accumulation should be analyzed in accordance with its geological settings.On basis of study of regional tectonics,special concerns should be put in the two foreland basins located in the north and south respectively.
CONTROL OF PALEOUPLIFTS TO THE MESO-PALEOZOIC PRIMARY OIL AND GAS POOLS IN THE SOUTH OF CHINA
ZHAO Zong-ju, ZHU Yan, DENG Hong-ying, XU Yun-jun
2003, 25(1): 10-17. doi: 10.11781/sysydz200301010
Abstract:
The Leshan Longnusi,Qianzhong and Jiangnan Uplifts mainly controlled the development of the Upper Sinian and the Lower Paleozoic primary oil and gas pools,while the Luzhou and Kaijiang Uplifts and the Late Paleozoic Triassic (isolated) anteclises in Nanpanjiang Shiwandashan area controlled the distribution of the Upper Paleozoic and the Triassic primary oil and gas pools.As the paleouplifts in the south of China have been reconstructed in different degrees,the intact uplifting faces do not exist already.There are few the Meso Paleozoic primary oil and gas pools existing presently in the south of China.The most early primary oil and gas pools in the Sichuan Basin were reconstructed to secondary gas pools,and the primary oil and gas pools in Yangtze and South China areas were mainly destoryed to fossil oil pools.It was suggested that the Meso Paleozoic hydrocarbon exploration in the south of China should mainly consider secondary oil and gas pools and regenerated hydrocarbon pools,that is,the secondary gas pools in the Upper Yangtze area and the regenerated hydrocarbon pools in the Middle Lower Yangtze area.Also,the specific favorable hydrocarbon exploration districts were pointed out,which were confirmed by the discovery of Zhujiadun gasfield in the Yancheng Depression of the North Jiangsu Basin and the West Kaixiantai oil bearing Structure in the South Chenhu area of the Jianghan Basin.
THE PERMIAN SEQUENCE STRATIGRAPHIC FRAMEWORK AND EVOLUTION OF SEDIMENTARY FACIES AND PALEOGEOGRAPHY IN GUIZHOU AND GUANGXI AREAS
JIAO Da-qing, MA Yong-sheng, DENG Jun, MENG Qing-fen, YI Ding-hong
2003, 25(1): 18-27. doi: 10.11781/sysydz200301018
Abstract:
The Permian system which includes the Chuanshanian,the Yangsingian and the Lopingian series can be divided into three series in Guizhou and Guangxi areas of South China.There are two obvious unconformities in the sequence,the one refers to the main episode of the Qiangui epeirogeny in the transitional period at the turn between Chuanshanian epoch and Yangsingian epoch,and another refers to the main episode of Dongwu movement in the transitional period at the turn between Yangsingian epoch and Lopingian epoch,both of which not only forms the evident sequence boundaries of type I but also represents the important changing surfaces of sedimentary facies and paleogeography.Obvious differentiation of depositional facies leads to the formation of a special pattern of paleogeography marked by "platformbasinhilltrough",especially for Lopingian epoch,which is reflected by lots of sedimentary features.For examples,coal measures are developed on the widespread platform,and sponge reefs are developed on the margin of the widespread platform as well as the isolated carbonate platform,furthermore,the period of the evident facies differentiation is corresponding to the development period of reefs,etc.The first episode of Dongwu movement in the transitional period at the turn between Yangsingian epoch and Lopingian epoch results in the great change of the paleogeographic pattern.Seven third order sequences can be discerned in the Permian of the study areas,i.e.,the top part of Carboniferous and the Chuanshanian series form one sequence (SQ19),four sequences which are from SQ20 to SQ23 are discerned in the Yangsingian series,and two sequences which are SQ24 and SQ25 are divided in Lopingian series.The typical drowned event of the carbonate platforms in the transitional period at the turn between Permian and Triassic shows that the top boundary of SQ25 is a obvious drowned unconformity.Therefore,the complex but regular facies changes in time and in space can clearly be illustrated in the series of the maps of sedimentary facies and paleogeography as well as the panel diagrams of sequence stratigraphic framework.
A STUDY OF HYDROCARBON-BEARING CHARACTERISTICS IN THE TANCHENG-LUJIANG FAULT ZONE
ZHANG Yun-yin
2003, 25(1): 28-32. doi: 10.11781/sysydz200301028
Abstract:
The Tancheng Lujiang fault zone is a vast structural zone in East China.Based on its basic structural characteristics,the geometry,kinematics and dynamics of the zone were analyzed and the hydrocarbon potential of basins around it was studied.It can be concluded as followings:(1) The formation and evolution of the Meso Cenozoic petroleum basins,such as Songliao Basin and Bahaiwan Basin in East China,were mainly controlled by the Tancheng Lujiang fault zone;and (2) The fault zone also played a very important part in formation and evolution of hydrocarbon pools.It controlled the development of source rocks,reservoirs and cap rocks and the generation,migration and accumulation of hydrocarbon in a basin.The occurrence of large or medium oilfields was closely related to the fault zone.
SEQUENCE STRATIGRAPHIC CHARACTERISTICS OF FLUVIAL FACIES IN THE QUANTOU FORMATION OF BUHAIHELONG AREA, THE SONGLIAO BASIN
FANG Shi, LIU Zhao-jun, HU Xian-hui
2003, 25(1): 33-38. doi: 10.11781/sysydz200301033
Abstract:
Based on the developing characteristics of fluvial facies and each sequence stratigrahic unit in the Quantou Formation of Buhaihelong area,the Songliao Basin,which was observed in outcrop,core and seismic data,the differences among the formation mechanism of three stream types were analysed from the angles of allogenic cycles and authigenic cycles.According to the controlling factor of allogenic cycles,that is,the changes of the base level,the sequence stratigraphic framework of the study area was divided,and the sequence stratigraphic model of fluvial facies was established.The lowstand system tract (LST) is dominated by lateral accretion and characterized by developing braided streams;the transgressive system tract (TST) is dominated by vertical accretion and characterized by developing reticulated streams;the highstand system tract (HST) is dominated by lateral accretion and characterized by developing lowenergy meandering streams;and the regressive system tract (RST) is dominated by lateral accretion and characterized by developing highenergy meandering streams.
EVOLUTIONARY CHARACTERISTICS OF THE CARBONIFEROUS SEDIMENTATION AND DIAGENESIS CONTROLLED BY THE SEQUENCE STRATIGRAPHIC FRAMEWORK OF THE WEST TARIM BASIN
WANG Qi, CHEN Guo-jun, XUE Lian-hua, SHI Ji-an
2003, 25(1): 39-44. doi: 10.11781/sysydz200301039
Abstract:
According to the ordered superimposed styles of high frequency cyclic sequences within long period cyclic sequences,three Ⅲ order cyclic sequences and two Ⅱ order cyclic sequenes were divided in the Carboniferous of the study area.Among them,Ⅲ 1 and Ⅲ 3 cyclic sequences belong to the transgressive tract system,and Ⅲ 2 belongs to the highstand tract system.They constitute together the sequence stratigraphic framework of the study area and control the space time distributive characteristics of sedimentary facies and source rock reservoir cap rock assemblages.As affected by the differences of diagenetic history and different diagenetic environments,the diagenetic characteristics and storage peformances of the Carboniferous clastic and carbonate reservoir rocks have obvious differences between the Bachu Uplifting area and the Maigaiti Slope area.Besides,the reservoirs distributing in the slope area have obviously better physical properties than those in the same formations of the uplifting area,and are the favorable exploration targets in the near future.
CHARACTERISTICS OF N-HEPTANE-SOLUBLE COMPONENTS IN THE MILD CHEMICAL OXIDATION DEGRADED PRODUCTS OF ASPHALTENE
LIAO Ze-wen, GENG An-song
2003, 25(1): 45-52. doi: 10.11781/sysydz200301045
Abstract:
Some hydrocarbon components adsorbed and included in the molecular skeleton of asphaltene.were subjected less reconstruction from the paulopost evolution of oil pools,and were thought to be primary and containing important organic geochemical information.The experimental results showed that these primary components in the molecular skeleton of asphaltene can be released rationally by mild chemical oxidation degradation treatment,and can obtained well application in oiloil correlation,oilsource correlation,the sedimentary environments of organic matter in oil pools,the secondary reconstruction of oil pools and other researches.To some oil pools subjected serious paulopost degradation,these components especially possessed important significance in the study of restoring original organic geochemical information.
PARTITION EXPERIMENT OF GC FINGERPRINT OF CRUDE OIL
JIN Xiao-hui, ZHU Dan, LIN Ren-zi, SHI Quan
2003, 25(1): 53-57. doi: 10.11781/sysydz200301053
Abstract:
The trace compounds in hydrocarbon can be discriminated and calculated by gas chromatography (GC).Chemical model of commingled production wells was established based on its developing process.Partition experiment and chemical simulation of GC fingerprint compounds were carried out in one reservoir of Gangxi area in Dagang oilfield.The results showed that not all GC fingerprint compounds were partitive,which were resulted from the geological setting of oil generation,the properties and concentration of oil composition,the resolution of chromatogram,and the quantitative method of fingerprint parameters.Therefore,only the partitive fingerprint compounds can be used to monitor the performance of developing wells.At the same time,the method provided a new thought for the quantitative simulation of hydrocarbon generation of different source rocks and for the monitoring of air and water pollution.
THREE MODELS OF RELATIONSHIP BETWEEN THE MATURITY INDEXES AND THE DEPTH IN THE NORTHERN JIANGSU TERTIARY BASIN
CHEN An-ding
2003, 25(1): 58-63. doi: 10.11781/sysydz200301058
Abstract:
The relationship between the four maturity indexes (Ro,sterane parameter αααC29-S/(S+R),mixed layer of illite/smectite and fission track) and the depth in the northern Jiangsu Tertiary Basin showed a parallel distribution from shallow to deep.The samples for study were from different sedimentary and structural settings with variable bury history.The shallow one represented structural uplift,the deepest one underwent short time heating,and the medium was long time heating type.It provided optional bases for estimation of erosion thickness in uplift areas.
STUDY OF ACCUMULATION COEFFICIENT OF COAL-FORMED GAS BELOW THE SALT SEQUENCE IN WENLIU AREA OF DONGPU DEPRESSION
XIONG Li-ping, WANG Yun-suo, XU Hua-zheng, WANG Rui-xia
2003, 25(1): 64-68. doi: 10.11781/sysydz200301064
Abstract:
The gas in Es3(4)below the salt sequence has single source in Wenliu area of Dongpu depression,and the boundary condition is clear for the source rocks in the CarboniferousPermian coalbearing sequence.Exploration degree is high in this area.Final proven reserves can be calculated accordingly by profound understand of natural gas reservoir formation condition,reservoir formation history and gas reservoir features.The quantity of gas generated from coal measure in the reference section can be calculated by the method of basin modeling,and natural gas accumulation coefficient is calculated as 7.3%-7.6%.
THE PATTERNS AND ITS EFFECT FACTORS OF SECONDARY HYDROCARBON MIGRATION
ZHANG Fa-qiang, LUO Xiao-rong, MIAO Sheng, WANG Wei-min, ZHOU Bo, HUANG Yan-zhang
2003, 25(1): 69-75. doi: 10.11781/sysydz200301069
Abstract(1115) PDF-CN(385)
Abstract:
Using porous media model in columns packed with glass beads under hydrostatic condition,the principles of hydrocarbon migration in porous media saturated with water were observed.Different geological factors associating with displacement forces have been tested.Migration front presented three patterns.The relationship among various parameters and its effect on migration pattern were analyzed according to capillary number and Bond number.The patterns include stable advancement,capillary finger and preferable migration pattern.Given the properties of carried beds,the preferable pathway of hydrocarbon migration depend on the single buoyancy or lesser displacement forces.
AN EXPERIMENT OF GENERATION AND EXPULSION OF OIL FROM THE JURASSIC COALS AND ITS IMPLICATION OF COAL GENERATED OIL IN THE ORDOS BASIN
LUO Xia, LI Jian, HU Guo-yi, WU Da-mao, LI Zhi-sheng, ZHANG Ying, YAO Jian-jun
2003, 25(1): 76-80. doi: 10.11781/sysydz200301076
Abstract:
It is a hot topic if the Jurassic coal can generate oil in the Ordos Basin.The adsorbed hydrocarbons amount in the Jurassic coal is 50-80 kg/t but the productivity of coal is only 6.02-70.7kg/t based on the experimental result.If produced oil is less than adsorbed oil in coal,the coal cannot be an effective source rock of oil.On the other hand,comparing to the coal of large and medium sized oilfields in the world,the Jurassic coal in the Ordos Basin is characterized by lower abundance,unfavorable type and lower maturity,which indicates uneffective source rocks.In terms of characteristics of biomarker,the Jurassic oil is not generated by coal in the Ordos Basin.Therefore,the Jurassic coal in the basin can not generate sufficient oil to form a commercial oilfield.
CHARACTERISTICS OF FLUID INCLUSIONS IN THE QIANGTANG BASIN AND THEIR APPLICATION TO THE STUDY OF RESERVOIR DIAGENESIS
XU Jian-hua, HOU Zhong-hao, WANG Jin-you, WU Tai-rong, ZHOU Li-jun, WANG Si-wen
2003, 25(1): 81-86. doi: 10.11781/sysydz200301081
Abstract:
According to the observed and measured data of fluid inclusions in the Qiangtang Basin in this paper,the main types and characteristics of fluid inclusions were studied comprehensively.Based on the study of diagenesis,the authors emphatically discussed the application of the fluid inclusion technology to the study of reservoir diagenesis.The succession of the TriassicJurassic diagenetic evolution in the Qiangtang Basin was established,and the relationship of diagenesis to hydrocarbon migration was analysed.This made a preliminary approach to the application of the fluid inclusion technology to reservoir research.
APPLICATION OF BASIN MODELING TO THE STUDY OF HONGZE SAG IN NORTHERN JIANGSU BASIN
WU Dong-ru
2003, 25(1): 87-92. doi: 10.11781/sysydz200301087
Abstract:
The Hongze sag is located in the northwest of the northern Jiangsu Basin,with some potential for hydrocarbon exploration.Based on the results of basin modeling,it can be concluded as following:a) most of source rocks are low matured and the matured source rocks are only restricted in the deep part of the sag;b) large scale of hydrocarbon generation and accumulation is occurred after sedimentation of Yancheng formation,but a lot of low or nonmatured oil were generated before Wubao and Sanduo movements;c) the deep part of the sag is the main area for hydrocarbon generation and accumulation;and d) distance of oil migration is short.In a word,the Hongze sag is characterized by low matured source rocks,short migration,and limited accumulation.It is necessary to pay more attention to the study of the sag for the sake of success of petroleum exploration in the area.
A METHOD FOR DETERMINING THE HISTORY OF FAULTS USING THE MODEL OF FAULT DISPLACEMENTS
SHAN Ye-hua, LI Zi-an, LIN Ge
2003, 25(1): 93-96. doi: 10.11781/sysydz200301093
Abstract:
There are extensive information on the nuclei,propagation and linkage of faults recorded by the displacements of faults.By utilizing the model of fault displacements,a method to study the history of faults based on observed data of fault displacement was proposed.Taking the Zhangdong normal fault in the inshore of the Dagang Oil Field as an example,the results showed that the restored fault displacement in different sedimentary stages tended to increase,decrease and then increase less with time.It reached the minimum of displacement during sedimentation of the Oligocene Dongying formation,and representd the relatively quiet epoch in regional extension.The parameter of fault propagation is larger in the Eocene than in the Neogene,the latter ca.1.0.This indicated the tendency of decrease in the fault activity with time,corresponding with the evolution of the basin which experienced intense riftsubsidence in the Eocene to depression in the Neogene.It was during the deposition of the Oligocene Dognying formation that the fault activity had generated both the maximum displacement and the maximum lateral variation in displacement.