石油实验地质

2003, 25(6): 627-627. doi: 10.11781/sysydz200306627

Abstract(546) PDF-CN(330)

Abstract:

PROBLEMS AND SUGGESTIONS ON MARINE PETROLEUM EXPLORATION IN SOUTH CHINA

CAI Li-guo

2003, 25(6): 634-636. doi: 10.11781/sysydz200306634

Abstract(618) PDF-CN(440)

Abstract:
The area of marine deposit in South China is about 50% of that in China.The marine sedimentary basins were incomplete.They have been reformed by structural movements taking place in the area.The distribution and structural styles of residual basins were greatly complex and inhomogeneous.The organic matter was overmature,and the models of accumulation and formation of oil and gas were complex in the area.The regularity of oil and gas pool formation is remained to be studied in the marine sedimentary basins of South China.The evolution and superimposition should be analyzed in the Paleozoic marine sedimentary basins and the Meso-Cenozoic nonmarine sedimentary basins together.The basic regularities of formation,migration and preservation of oil and gas should be studied.The further studies would be the effective reformation and superimposition of proto-type basins,the effective sources rocks,the effective preservation conditions and the effective petroleum systems.In the potential areas,comprehensive studies must be made in order to make a breakthrough in oil and gas exploration.The effective migration and pre-servation of oil and gas must be deeply studied in middle to long term exploration areas.

FORMATION FEATURES OF MIDDLE-LARGE SCALE LITHOLOGIC OIL AND GAS FIELDS IN THE SLOPES OF MAIN TERRESTRIAL OIL BASINS OF CHINA

ZHOU Li-qing, LIU Chi-yang, ZHANG Huai, LU Huang-sheng

2003, 25(6): 637-643. doi: 10.11781/sysydz200306637

Abstract(473) PDF-CN(560)

Abstract:
Various kinds of terrestrial oil basins are evolved in China,and the formation features of middle-large scale lithologic oil and gas fields in the slopes of the basins are different.The structural partition in the extensional faulted Meso-Cenozoic basins is strong.And in the sags with high-very high hydrocarbon abundance,large types of radial distributed fan deltas and underwater alluvial fans are often superposed in slope areas,and middle-large scale lithologic complex oil and gas reservoirs are formed under the control of faults,formation overlap and pinchout,igneous rocks,and mud diapir.Middle-large scale hydrocarbon accumulating units are evolved in the huge Late Cretaceous Songliao Down-warped Basin which is formed due to heat decreasing,and the basin is of high-very high hydrocarbon abundance.By the controlling of regio-nal faults and bulges from bottom,middle-large scale lithologic-faulted oil reservoirs are formed in the slope areas in which middle-large scale of superposed delta sandstone bodies and tilted and inversed structures are evolved.Large hydrocarbon accumulating units are formed in the steady craton basins such as the Late Paleozoic Ordos Basin and the Mesozoic Shanganning Basin with middle scale of hydrocarbon abundance.The large-middle types of alluvial-delta sandstone bodies at the northeast parts of the basins are always the hydrocarbon accumulating systems receiving hydrocarbon from the hydrocarbon-generating center at the southwest parts of the basins.Under the violent deformation the of Yanshannian-Ⅳmovement,large-middle types of lithologic oil fields are formed in sandstone bodies which distribute in the north-south direction and pinchout eastward.Because the large-middle types of hydrocarbon accumulating units are formed in main sags,the large Mesozoic forland basins such as the Junggar Basin,the West Sichuan Basin and the Tarim Basin are of middle scale hydrocarbon abundance,and a series of middle-small types of skirt-edged fans by radial distribution are formed in the slop areas.And under the background of big existed bulges,formation overlaps and pinchouts as well as faults,lithologic oil fields can be formed in the fans.

ADVANCES AND TENDENCIES IN GEOLOGICAL RESEARCHES ON COALBED METHANE

TANG Da-zhen, QIN Yong, HU Ai-mei

2003, 25(6): 644-647. doi: 10.11781/sysydz200306644

Abstract(711) PDF-CN(476)

Abstract:
We are presently involved in the challenge of geological research on coalbed methane,including:a)to reveal the coordinated relationship between the generation and the preservation of coalbed methane and to discover the forming mechanism,pool-forming types and distribution rules of coalbed methane pools under complex geologic conditions by studying on the geologic processes and dynamical mechanism of pool-formation;b)to analyse the processes of diffusion,percolation,migration,escaping and accumulation of coalbed methane which are commonly restricted by coal-water-gas coupling connection and coal-reservoir features by studying on the reservoir systems and accumulating-disseminating mechanism of coalbed me-thane;c)to probe into the mutual stimulating mechanism between the geophysical and geochemical field and man-made reconstruction and intensified exploitation and to effectively predict the results of exploration and exploitation of coalbed methane by studying on the field effects during the economical and high-efficiency exploitation of coalbed methane pools.

OROGENY AND COUPLED/DECOUPLED BASIN DEVELOPING：APPLICATION IN PETROLIFEROUS BASIN ANALYSES

WU Gen-yao, MA Li

2003, 25(6): 648-660. doi: 10.11781/sysydz200306648

Abstract(702) PDF-CN(344)

Abstract:
Chinese geologists had a correct understanding of some specific characteristics on petroliferous basins in China continent,and named them superimposed basin,composite one,reformed one,residual one,relict one,etc.The paper aimed to deepen our comprehensions on the basins' mechanics and features in the light of orogeny and coupled/decoupled basin developing.The creation of inheritance-type of superimposed basin,with the Junggar Basin being an example,was caused by a "basin"-"orogen"relation constituted in the Hercynian orogeny keeping on during Meso-Cenozoic,not decoupled so far.If a "basin"-"orogen"relation setting up in the Indosinian orogeny decoupled and a part of cratonic area locked in the Yanshanian or Himalayan movement,the part could be classified into alteration-type of superimposed basin.Taking the Sichuan,Ordos and Tarim Basins as an instance,the locked conditions were analysed thoroughly.The essence of basin superimposition should be a replacement of "basin"-"orogen"system.Some possibly complicated cases of replacement of "basin"-"orogen"system were discussed in the paper.Composite basin might occur in every stage of an orogenic process.Some so called "composite basin",for example,the Chuxiong Basin in Yunnan,might be a sediments' collage,which resulted from migration and collage of sediments originally in varied basins by multiple orogenies.Residual basin was different from relict basin which was a prototype one.To study a residual basin,the key problem might be mode or style of basin reformation,and then the conditions for secondary hydrocarbon generation in later period.A new leap of oil-gas exploration in China would depend on new progresses of understanding on the residual marine basins in age of Paleozoic and Early-Middle Triassic;and the leap of oil-gas exploration would carry on within a new theoretical frame.The orogeny and coupled/decoupled basin developing,dealing with a uniform kinematic process and geodynamic mechanics between "basin" and "orogen",would play an important role in the new leap.

EXTENSION AND SUBDUCTION OF THE MESO-CENOZOIC TARIM BASIN AND THEIR RELATIONSHIP WITH MANTLE PLUME

GAO Chang-lin, YE De-liao, ZHANG Yu-zhen, LIU Guang-xiang

2003, 25(6): 661-669. doi: 10.11781/sysydz200306661

Abstract(736) PDF-CN(461)

Abstract:
Since the Permian,the Tarim Basin had undergone basinal extension,subduction and intro-continental orogeny.Basinal extension and subduction was related to activity of mantle plume,formation and evolution of mantle plume resulted in geothermal decreasing of lithosphere in the basin.A huge thermal dome structure was firstly formed in continental crust due to rising of hot mantle plume during the Early Permian,and graben and fault basin were further formed.During the Late Permian to Triassic,intra-continental down-warped basin was formed in the central part of the basin as a result of thermal decreasing from mantle after eruption of mantle plume material in the Early Permian;however,strong compression was occurred from centre to outsides because of raising of mantle material,Tianshan and Kunlunshan were fastly uplifted and thrusted towards the basin,and two foreland basins were formed respectively.From the Jurassic to the Cretaceous,it was a thermal decreasing period in the basin,as a result,intra-continental down-warped basin was formed.It was a relative fast period for geothermal decreasing during Cenozoic,which corresponded with continental convergence,subduction,thrust-nappe and collisional orogeny in the area.Mountain system around the basin was uplifted continously and the basin was subducted.Just because of formation and evolution of mantle plume,it resulted in inner basinal extension,subduction and intra-continental orogeny.The protobasin in Meso-Cenozoic includes transverse extensional basin (Early Permian),intra-continental foreland basin and down-warped basin (Late Permian-Triassic),intra-continental down-warped basin (Jurassic-Cretaceous) and late foredeep basin(Cenozoic).

COUPLING RELATIONS BETWEEN THE HEFEI BASIN AND THE DABIE-ZHANGBALING OROGENIC BELT

ZHAO Zong-ju, ZHU Yan, XU Chun-hua, ZHOU Jin-gao, YI Wan-xia, SHEN Jin-long

2003, 25(6): 670-678. doi: 10.11781/sysydz200306670

Abstract(604) PDF-CN(479)

Abstract:
The existing Dabie-Zhangbaling Orogenic Belt,whose formation and evolution apparently controlled the features and evolution of the Meso-Cenozoic Hefei Basin,has been formed since the Indosinian epoch.There were close coupling relations between the basin types and its reforming styles of the Hefei Basin in the different periods of the Meso-Cenozoic and the moving styles of the Dabie-Zhangbaling Orogenic Belt:a) the coupling of the thrust reformation in the Indosinian (the Middle-Late Triassic) displayed in where the Hefei Basin is with the syncollision compressive obduction orogenesis which resulted in the final collision and matching of the Yangtze Plate and the Huabei Plate and the formation of the Dabie-Zhangbaling Orogenic Belt;b) the coupling of the formation of the paraforeland Hefei Basin in the Jurassic with the strong buoyancy diapir orogenic uplifting of the Dabie-Zhangbaling Orogenic Balt resulted from the folding subsidence of the underthrust Yangtze Plate and the further matching compressive orogenesis of the Yangtze-Huabei Landmass;c) the coupling of the formation of the slide-overlap and strike-slip composite Hefei Basin in the Early Cretaceous with the thermal-uplifting extension of the Dabie Orogenic Belt and the strike-slip movement of the Zhangbaling Orogenic Belt;d) the coupling of the thrust reformation displayed by the major Hefei Basin in the early stage of the Late Cretaceous and the formation of down-warped basins in the northeast part with the thermal-uplifting extension of the Dabie Orogenic Belt and the weak compression of the Zhangbaling Orogenic Belt;e) the coupling of the formation of tenso-shear rift basins in the late stage of the Late Cretaceous to the Paleogene with the postorogenic collapse of the Dabie-Zhangbaling Orogenic Belt and the differential elevation and subsidence of fault blocks;f) the Dabie-Zhangbaling Orogenic Belt since the main episode of the Himalayan movement in the Oligocene totally displaying weakly compressive and compresso-shear orogenic uplifting and being gradually denuded and leveled,and providing material sources for the down-warped deposition of the Hefei Basin in the Neogene-Quaternary.

ANALYSES ON OIL AND GAS EXPLORATION PROSPECTS IN THE ZHOUKOU RESIDUAL BASIN

YUAN Zheng-wen, HE Ming-xi, SONG Jian-hua, GU Zhe, DU Jian-bo

2003, 25(6): 679-684. doi: 10.11781/sysydz200306679

Abstract(497) PDF-CN(406)

Abstract:
The reformation characteristics of three-period compression and two-period extension suffered by the prototype depositional basin of the Zhoukou Depression were analyzed in this paper at first.Then two groups of major residual oil source rocks in the Lower Cretaceous and the Carboniferous-Permian were determined through oil-source correlation.According to the relations of "construction to reformation" and "destruction to preservation",four kinds of pool-forming units were identified,the thermal evolution history of petroleum systems in the residual basin was analyzed,and three types of hydrocarbon accumulation patterns such as "self-generation and self-preservation","generation in lower zones and preservation in upper zones" and "fossil buried hills"were predicted.The authors emphasized that the inhomogeneity of thermal evolution created certain conditions for secondary oil generation,and the strength and range of secon-dary oil generation were controlled by the Early Tertiary fault structures in overlying formations.So the secondary oil generation and the pool-formation in late periods were determined as main research directions for further exploration.To study the necessary conditions of "oil generation in lower zones and preservation in upper zones" and the favorable occurrences for pool formation in later periods can help us to exactly find the breakthrough points of hydrocarbon exploration in residual basins.

STRUCTURAL CHARACTERISTICS AND EXPLORATION POTENTIAL OF THE THRUST BLOCK IN LONGMENSHAN

YANG Ke-ming, ZHU Tong, HE Li

2003, 25(6): 685-693. doi: 10.11781/sysydz200306685

Abstract(672) PDF-CN(494)

Abstract:
The Longmenshan structural zone is divided into Maowen ductile shear zone,Longmenshan imbricated thrust structural zone and Longmenshan thrust nappe structural zone from west to east according to its deformation characteristics.And the Longmenshan thrust nappe structural zone can be further divi-ded into two subzones,foremountain zone and concealed zone where is idea position for hyarocarbon accumulation.As to the foremountain zone,the relativehy stable structure and good closing and capping capability are the master elements for hydrocarbon accumulation.And for the mountain front concealed zone,the master elements are the polymerzation of old and present structure,relatively active structure and where fissures develop.Thus it is predicted that,the most favorable exploration area for natural gas is the Cifengchang high part in the hanging wall of concealed fault belt in Guankou-Shuikouchang,the Gaojia-chang,Shuikouchang,Youzhatuo and Shibantan structural zones and Pingluoba in the footwall,as well as Qiongxi,Dayi and Yazibe anticlines.

ANALYSIS OF SEQUENCE STRATIGRAPHY FOR TAIKANG-XICHAO AREA OF THE NORTH SONGLIAO BASIN

LI Yu-le, ZHANG Yin-guo, CHEN Jian-wen

2003, 25(6): 694-700. doi: 10.11781/sysydz200306694

Abstract(608) PDF-CN(405)

Abstract:
This paper focused on the application of high-resolution sequence stratigraphy to the formations,i.e.,the second and the third sections of the Qingshankou-Yaojia Formation and the first section of the Nenjiang Formation in Taikang-Xichao area of the North Songliao Basin.Based on the comprehensive study of logging,drilling and seismic information,two scales of stratigraphic cycles (short-term and intermediate-term) can be recognized in the study area.The formations were divided into thirteen chronostratigraphic boundaries,including six sequence boundaries,which were the transformation from base-level fall to base-level rise,and seven lake-flood surfaces,which were the transformation from base-level rise to base-level fall.Then,features of these sequences were described detailed and sequence stratigraphical patterns were analyzed.This will be of guide significance for the discovery of non-structural reservoirs.

DEFORMATION CHARACTERISTICS AND PETROLEUM GEOLOGICAL SIGNIFICANCES OF COMPRESSO-SHEAR STRESS FIELDS IN THE WEST SICHUAN DEPRESSION

HUANG Ze-guang, LIU Guang-xiang, PAN Wen-lei, ZHAI Chang-bo

2003, 25(6): 701-707. doi: 10.11781/sysydz200306701

Abstract(702) PDF-CN(419)

Abstract:
By analysing on the formation,evolution and sedimentary distribution characteristics of the West Sichuan Depression since the Late Triassic and the deformation of the Longmenshan Thrust Belt,it was considered that the Longmenshan Thrust Belt was in the environment of compressive stress field during the Indosinian period,and formed the NEE-oriented and uplift-depression alternated tectonic belt in the Early-Middle Yanshanian period under the action of sinistral compresso-shear stress.The fissures and microfissures formed in the upfolded belts greatly improved the reservoir capacity of dense sandstone,and were favorable to the enrichment and accumulation of oil and gas.

THE GEOLOGICAL PROPERTIES OF NATURAL GAS AND EXPLORATION PROSPECTS OF UPPER PALEOZOIC IN TABAMIAO AREA, NORTH ORDOS BASIN

MENG Jun-tian, JIA Hui-chong

2003, 25(6): 708-711. doi: 10.11781/sysydz200306708

Abstract(556) PDF-CN(345)

Abstract:
Tabamiao area is situated in Yishan slope of Ordos Basin.The coal and dark mudstone beds in Taiyuan and Shanxi Formations possessed favourable hydrocarbon generation ability.Sandbodies which deposited in river channels,fan deltas and tidal flat are main reservoirs.Multiple source-reservoir-cap assemblage in vertical provided favourable condition for gas pool forming.The natural gas resource of Upper Paleozoic in Tabamiao area is up to 6 174×10⁸m³ and its proved rate is only 11% at present.Therefore,the Upper Paleozoic in Tabamiao area is favourable for gas exploration.It is considered that the reservoir characteristics was controlled by the sedimentary microfacies and the future exploration should be focused on search for lithologic traps in Tabamiao area.

THE TECTONIC EVOLUTION AND RESERVOIR FORMATION IN WENLIU AREA, BOHAIWAN BASIN

XU Hua-zheng, HOU Xin-ke

2003, 25(6): 712-720. doi: 10.11781/sysydz200306712

Abstract(1379) PDF-CN(371)

Abstract:
Wenliu structure is an anticline caused by salt-gathering on the background of center mole track,it was formed from Es³⁽²⁾to Es².The extent of the trap is enlarged because of the salt-slumping of the wings.With the increase of the burial depth,C-P coal formation began its secondary hydrocarbon generating,and started migrating at depth of 4 000m for the first time.The main source rock was located in Wendong and Qianliyuan areas,with the depth of 5 200～6 300m.Micro-fracture-fault network was the main way for the coal-derived gas to migrate to the center mole track,the migration reached its peak at the age Ed (Ⅱ episode).In the trap,the gas prefered to entering the typeⅠand Ⅱreservoirs in Es^4(3-5)(the water-displacement rate is 73%～56%),then with the increase of the gas column and pressure,the gas began to enter the type Ⅲ of reservoir in Es^4(1-2 and Es^4(7-8),the final water-displacement rate is 40%.

ANALYSIS ON THE PETROLEUM RESOURCE DISTRIBUTION AND EXPLORATION POTENTIAL OF THE XIHU DEPRESSION, THE EAST CHINA SEA

LI Shang-qing, LI Chun-jie

2003, 25(6): 721-728. doi: 10.11781/sysydz200306721

Abstract(556) PDF-CN(365)

Abstract:
Based on the detailed analyses and discussion of petroleum geological conditions of the Xihu Depression,the East China Sea,this paper systematically calculated the potential petroleum resources,resources in leads and total resources,and then established the series and structure of resources and presented the distribution characteristics of discovered and undiscovered resources.The Concept of petroleum resource abundance was introduced to estimate the exploration potential of the Xihu Depression,especially the Baoshu Slope and the Central Anticlinal Belt,by comparing with the resource abundance of the other depressions in East China.

DIAGENESIS AND POROSITY EVOLUTION OF THE ORDOVICIAN CARBONATE ROCKS IN TAHE OILFIELD, TARIM BASIN

CHEN Qiang-lu, QIAN Yi-xiong, MA Hong-qiang, Wang Shu-yi

2003, 25(6): 729-734. doi: 10.11781/sysydz200306729

Abstract(560) PDF-CN(407)

Abstract:
The carbonates of Ordovician are the principal reservoirs in Tahe oilfield,Tarim Basin.The diagenesis of Ordovician carbonates is characterized by multiple stages,different types and enviroments.The major diagenesis includes cementation,solution,fracture and hydrothermal diagenesis which controlled the evolution of reservoirs.The history of dagenesis and porosity evolution and the origin of formation of the Ordovician reservoirs were reconverted.

HYDROCARBON ACCUMULATION CHARACTERISTICS OF COMBINATION TRAPS IN THE ABDOMEN OF JUNGGAR BASIN

WU Jin-cai, ZHANG Jian-zhong, SHI Hao-guo, WANG Li-chi, MENG Xian-long, ZHU Yun-hui

2003, 25(6): 735-739. doi: 10.11781/sysydz200306735

Abstract(677) PDF-CN(466)

Abstract:
Junggar Basin is a highly explored basin,with few unexplored structural traps remaining.Thus the lithologic trap,and even the structural lithologic trap,have become the main target of oil-gas exploration.This is especially evident in the abdomen of Junggar Basin,where the weak structural movement resulted in less structural trap,making it more urgent to look for lithologic or structural lithologic combined traps.According to the sedimentary facies analysis with seismic stratigraphy and sequence stratigraphy,in the abdomen of Junggar Basin,the Jurassic Sangonghe formation and Bandaowan formation in the main target strata are mainly flurial-delta-semi-deep lake facies.And the reservoirs are mainly composed of various kinds of channel sand and deltaic front sand.In accordance with the research on structural evolution,the suprastructure (Jurassic and overlying formation) in the abdomen of Junggar Basin is mainly monoclinal formation uplift to the north.This structural background,combined with various kinds of lithologic sand,forms combination trap.The complicated distribution of Jurassic and Cretaceous sand results in the complex relationship between oil and water in the study area,thereby makes the combination on accumulation quite complicated.

INVESTIGATION OF OIL SECONDARY MIGRATION IN CAINAN OILFIELD USING PYRROLIC NITROGEN COMPOUNDS-A CASE STUDY OF THE JURASSIC XISHANYAO RESERVOIRS IN THE EASTERN DISTRICT OF CAINAN OILFIELD

WANG Chuan-gang, WANG Tie-guan

2003, 25(6): 740-745. doi: 10.11781/sysydz200306740

Abstract(841) PDF-CN(384)

Abstract:
In recent years,pyrrolic nitrogen compounds were successfully utilized for the research of oil migration ways in the world.Oil samples from reservoir Xishanyao Group in the eastern district of Cainan oilfield are the same oil family,in which pyrrolic compounds are dominated by alkyl-carbazole and C₂-,C₃-carbazoles constitute the main parts of alkyl-carbazole.The analyses of parameters for the migration fractionation effects of pyrrolic compounds indicated that there were two oil recharge directions including the north and the west,and the reservoir-inner faults may facilitate oil migration processes.The Jurassic coal-bearing strata in the North Dongdaohaizi Depression which lies to the west of the Baijiahai Uplift are pro-bably the main hydrocarbon source kitchen.Furthermore,an other source kitchen in the Fukang Depression and its north slope which lie to the south of the Baijiahai Uplift is also undeniable.

PETROLEUM GEOCHEMISTRY AND HYDROCARBON MIGRATION IN TAHE OILFIELD OF THE TARIM BASIN

GU Yi, HUANG Ji-wen, SHAO Zhi-bin

2003, 25(6): 746-750. doi: 10.11781/sysydz200306746

Abstract(778) PDF-CN(463)

Abstract:
Based on study of relationship between petroleum geochemistry and hydrocarbon migration of the Ordovician oil in Tahe oilfield of the Tarim basin,it was indicated that:a)the physical properties of oil and gas may macroscopically show direction of hydrocarbon migration;b)light hydrocarbon,biomarker and nitrogenous compounds of crude oil can better reflect direction of oil gas migration,i.e.biomark compound of saturated hydrocarbon represents migration direction of relative light oil and nitrogenous compounds are indicator of relative early migration;c)direction of hydrocarbon migration was from south to north in the early stage but it migrated both from south to north and from east to west in the late in Tahe oilfield.

THE OILFIELD WATER IN TAHE AREA, TARIM BASIN-CONSTRAINTS FROM ITS ELEMENT COMPOSITION

QIAN Yi-xiong, CAI Li-guo, GU Yi

2003, 25(6): 751-757. doi: 10.11781/sysydz200306751

Abstract(479) PDF-CN(469)

Abstract:
The wide range variation of composition of (oilfield) formation water in the different geological era are likely to represent the complex origin and evolution history of fluid.It is thus important to understand how to describing the evolution of water.In order to demonstrate the relative richness of elements in the evaporation and condensation of seawaters and effect on composition variation of oilfield water in water-rock reaction,we have studied the evolution of water in terms of oxygen,carbon isotopes and a great number of chemical components of oilfield water,combined with the comparison among the components of oilfield water or the average seawater composition or brine water undergone the evaporation and condensation of seawater or meteoric water in the dilution and weathering process.The results suggest the marine carbonate rocks -related origin of Ordovician formation water with good proxy indicator of ratio of Cl^-/Br^- (322～337),which approach to the minimum richness content in a preserved pHanerozoic marine seawater,as well as high richness of halogen elements of Br,Cl and I,volatility elements of F,Cl and B,and Iron cluster elements of V,Cr,and so on,the Carboniferous formation water is characteristic of dilution and filtration process with ratio of Cl^-/Br^- as high as 1 399.8,while the Triassic formation water contains relatively high contents of Pro-copper cluster elements and germanium(Ge),indicating a significant input of meteoric water during the late diagenetic process.the isotope records of δ¹⁸O、 δ D and⁸⁷Sr/⁸⁶Sr of formation water shows a significant feature of “metamorphic water ”with a much negative shift of δ¹⁸O of Triassic formation water.In conclusion,the composition of Ordovician formation water have been mainly controlled by evaporation and condensation of ancient seawater,undergone a series of dilution input and mixing of meteoric water in the early period of Hercynian,the Carboniferous formation water have been related to dilution and filtration as well as chemical interaction between the meteoric water and gypsum-bearing or halite rocks;while the Triassic formation water maybe derived from mixing and rock interaction with meteoric water.

STUDY ON THE MODELS OF HYDROCARBON GENERATION AND EXPULSION FROM VARIOUS SOURCE ROCKS IN COAL-BEARING ENVIRONMENTS

QIN Jian-zhong, LIU Bao-quan

2003, 25(6): 758-764. doi: 10.11781/sysydz200306758

Abstract(474) PDF-CN(389)

Abstract:
Using new technologies such as the thermo-pressure simulation experiment and hydrocarbon geochemistry,the hydrocarbon generation and expulsion models for various source rocks in coal-bearing environments were studied in detail on the bases of the systematic analysis and summarization of a number of geochemical and geological data.There are dramatic differences in hydrocarbon generation potential among dark mudstone,carbargillite and coal in coal-bearing environments.The coal and carbargillite formed in shore swamp are better than the mudstone,but the mudstone formed in relative deep to shallow lacustrine (sea) is better than the coal.Nine hydrocarbon generation and expulsion models for four organic matter types and two main rocks in coal-bearing environments were established,and the models were tested byreal geological profiles.The ability of hydrocarbon expulsion for mudstone with type Ⅲ1-Ⅱ1 organic matter is in an advantageous position comparing with coal and carbargillite in coal-bearing environments.

METHOD STABILITY AND ANOMALY REPRIDUCIBILITY ANALYSIS IN SURFACE GEOCHEMICAL EXPLORATION FOR OIL AND GAS-A CASE STUDY OF THE SHIWU FAULT DEPRESSION IN SONGLIAO BASIN

YAO Jun-mei, XIA Xiang-hua, REN Chun

2003, 25(6): 765-768. doi: 10.11781/sysydz200306765

Abstract(628) PDF-CN(392)

Abstract:
Based on the results of repetitive tests above the existing oil and gas fields in Shiwu fault depression in southeastern uplifted area in Songliao Basin,the method-stability of acid-digestion hydrocarbon,heat-release hydrocarbon,headspace gas and ΔC and reproducibility of the anomalies determined by these indicators are discussed.The results showed that the concentrations of the geochemical indicators in repetitive tests had stability to a certain extent.And in special distribution,the anomalous zones defined by the geochemical indicators in repetitive tests had reproducible features.The medium-value and high-value anomalies of the indicators had better reproducibility above oil and gas fields.The concentrations of the indicators in background areas were lower.

CHARACTERISTICS OF HYDROCARBON SOURCE ROCKS IN THEJURASSIC SHEMSHAK FORMATION OF KASHAN AREA, IRAN

WANG Shi-hu, LI Zheng, XIA Bin, CHEN Gen-wen, YAN Yi, YU Jun-feng, CHEN Zhi-yong

2003, 25(6): 769-772. doi: 10.11781/sysydz200306769

Abstract(640) PDF-CN(392)

Abstract:
By analyses on the organic matter abundance of hydrocarbon source rocks,the vitrinite composition and carbon isotopic features of kerogen and the features of biomarkers in the Jurassic Shemshak Formation of Kashan area,Iran,it was suggested that the kerogen types of the Shemshak source rocks be mainly sapropel-humic(Ⅱ2) and humic(Ⅲ).Most samples have evolved to overmature stages.Except for a few good source rocks,most source rocks of the Shemshak Formation are middle grade.

DISCUSSION ON THE VERTICAL CHARACTERISTICS OF OIL-GAS OXYGENATION LEVEL AND ITS PRESERVATION CONDITION IN PETROLEUM BASIN—A CASE STUDY ON THE CONTINENTAL TERTIARY BASIN IN LUNPOLA, TIBET

FU Xiao-yue, LU Ya-ping, XIAO Qiu-gou

2003, 25(6): 773-776. doi: 10.11781/sysydz200306773

Abstract(591) PDF-CN(409)

Abstract:
In this article,we discuss the vertical characteristics of oil-gas oxygenation level and its preservation condition in petroleum basin.The exploration data indicate that oil-gas oxygenation level in Lunpola Basin,Tibet is about 1 300m.The main provement of the existence of oil-gas oxygenation level in this basin is the physical and chemical characteristics and chemical type of crude oil,as well as the largest depth of where the oxidized asphalt exists.According to the physical and chemical characteristics of crude oil,oil-gas distribution and the changes of seal characteristics in accordance with its depth,we divide the oil-gas preservation condition in Lunpola Basin into three belts vertically:the oxygenation zone less than (1 000)m,the intermediate zone from 1 000m to 1 300m,and the preservation zone more than 1 300m.

NEW TECHNOLOGICAL ADVANCES IN PETROLEUM EXPLORATION

LIU Wei-xin, BA Li-qiang, ZHANG Mei-zheng, JIANG Qi-gui, QIN Jian-zhong, CAO Yin

2003, 25(6): 777-782. doi: 10.11781/sysydz200306777

Abstract(561) PDF-CN(399)

Abstract:
New analytic technologies in petroleum geological research and exploration activities have made great progress in recent years.Especially there has been a burst in the fluid inclusion study of oil-bearing sequences,which can determine the timing and physical-chemical conditions in the past.Light hydrocarbon analytic methods is making much progress,especially in source rocks.The alkylphenol and benzocarbazole extraction methods are also successful,and the changes in benzocarbazole concentration and the ratio of benzocarbazole can be used to discuss hydrocarbon migration.Also,the analytic method of clay minerals including mixed layer I/S,illite,etc.has developed fast.For example,the crystallinity values of illite are wildly used in the petroleum geological exploration of Songpan region.

STUDY OF PETROLEUM RESOURCE POTENTIAL APPLING OIL-ACCUMULATING UNITS IN THE JIYANG DEPRESSION

SUI Feng-gui, LUO Jia-qiang

2003, 25(6): 783-787. doi: 10.11781/sysydz200306783

Abstract(679) PDF-CN(327)

Abstract:
The petroleum system philosophy has great utility for evaluating oil-gas resource potential,understanding the distribution law of hydrocarbon and guiding oil-gas exploration in basins.The petroleum system subdivision is based on the critical process analysis of hydrocarbon from source rocks to traps.In this process,the largest outside boundary of oil-gas migration in a 3-D geological unit can be traced.The research on oil-gas secondary migration plays the leading role in the subdivision.The Jiyang Depression was divided into 28 oil-accumulating units on the basis of the petroleum system philosophy from source rocks to traps in the Eogene petroleum resource evaluation of the Jiyang Depression.Petroleum resources of every oil-accumulating unit were calculated on the bases of basin simulation and the study of hydrocarbon expulsion coefficient and accumulation coefficient.The resource potential was analyzed in the light of the petroleum resource volume and the prospect petroleum resource volume.The abundant degree of prospect petroleum resources and the future petroleum explorative potential in the Jiyang Depression is still great.

2003 Vol. 25, No. 6

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