石油实验地质

2008, 30(5)

Abstract(199) PDF-CN(296)

Abstract:

Gao Changlin, Liu Guangxiang, Huang Zeguang, Pan Wenlei, Fang Chengming

2008, 30(5): 429-434. doi: 10.11781/sysydz200805429

Abstract(602) PDF-CN(263)

Abstract:
There are lots of different opinions in petroliferous basin system research.According to analysis of basin system,comprehension of standards of oil and gas resources assessment,classification and comparison of basins in science and technology,basin system research can be divided into 2 parts,i.e.basin philosophy and basin technology.With modern geology,geophysics and geochemistry theories,basin philosophy studies the ontology,epistemology and disposition of basins.Rules of basin evolution and hydrocarbon generation can be obtained by basin philosophy studies.With modern geology,geophysics,geochemistry and applied math theories,basin technology studies evolutions of basin and hydrocarbon,providing technique supports for resource assessment.

PALEOZOIC DEEP STRUCTURE AND MARINE PETROLEUM EXPLORATION IN THE NORTHERN JIANGSU BASIN

Fan Xiaolin, Fang Chengming, Lü Junxiang, Pan Wenlei

2008, 30(5): 435-438. doi: 10.11781/sysydz200805435

Abstract(745) PDF-CN(364)

Abstract:
Due to stages of tectonic movements,deep sediments of Paleozoic in the Northern Jiangsu Basin have been completely transformed.Based on field geologic survey and underground geophysical data,geologic-geophysical comprehensive interpretations have been done.Paleozoic deep in the basin can be divided into 2 layers presently and is not totally inheritant.Combined with destroyed ancient accumulations regionally,it is suggested that tectonic ways should be used in marine petroleum explorations in the region.

MESOZOIC-CENOZOIC BASIN SUPERIMPOSITION AND UPPER PALEOZOIC HYDROCARBON GENERATION DISCIPLINE IN THE MIDDLE AND SOUTH OF BOHAI BAY BASIN

Hu Zongquan, Zhu Jianhui

2008, 30(5): 439-444. doi: 10.11781/sysydz200805439

Abstract(722) PDF-CN(262)

Abstract:
The Upper Paleozoic coal bearing formation in the Bohai Bay Basin is favorable for gas generation.It has undergone complex basin superimposition,resulting in differences of hydrocarbon generation history among different areas.Triassic,Jurassic-Cretaceous and Cenozoic are the 3 periods of hydrocarbon generation of the Upper Paleozoic source rock.Time,style and imbalance of Mesozoic-Cenozoic basin superimposition control hydrocarbon generation amounts and ratio in different periods and transference of hydrocarbon generation centers,which control hydrocarbon potential and distribution of the Upper Paleozoic.Imbalance of basin becomes stronger in the late period.Hydrocarbon generation intensity of the Upper Paleozoic source rocks in the early period is relatively stable;however,strong hydrocarbon generation may also exist in some regions during the late period.With fewer basin superimposition stages,fewer overlying strata,shallower imbedding depth in Mesozoic and deeper imbedding depth in Cenozoic,the Upper Paleozoic source rocks have greater generation potential in the late period.Based on geological model of secondary hydrocarbon generation and numerical simulation,hydrocarbon generation potential of the Upper Paleozoic in different sags is evaluated.

GEOLOGIC CHARACTERISTICS OF NATURAL GAS ACCUMULATIONS IN THE NORTHWEST OF GUIZHOU

Wang Jinyi, Tu Wei, Zeng Huasheng, Pan Wenlei, Wu Weiwen

2008, 30(5): 445-449. doi: 10.11781/sysydz200805445

Abstract(824) PDF-CN(310)

Abstract:
The northwest of Guizhou is the main generation and distribution region for Lower Cambrian Niutitang Formation,Lower Silurian Longmaxi Formation and Upper Sinian Doushantuo Formation source rocks.Studies of source rock evolution histories in Guanling County,Zhuzang Town of Zhijin County and Yankong Town of Jinsha County have indicated that,petroleum generates and evolves slowly in Yankong Town and kerogen is degradated completely,which is favorable for hydrocarbon generation.Tectonic evolutions in the northwest of Guizhou are controlled by ancient tectonic effects leading by Middle Guizhou Uplift.Hydrocarbons mainly accumulate around source rocks.Middle Guizhou Uplift near petroleum generation center is favorable for petroleum migration and accumulation.Large lithologic and tectonic traps provided by ancient uplifts are main locations for oil and gas pools.Uprises and erosions in late Caledonian destroy early pools.Tectonic movements after Yanshanian are the keys for pool destroy and preservation.Cambrian and Silurian pressure system still exist in the northwest of Guizhou,where petroleum units may still exist.

POOL FORMING CONSTRAINS AND THE HYDROCARBON EXPLORATION POTENTIAL OF THE WEST AFRICA COAST BASINS

Lin Weidong, Chen Wenxue, Xiong Liping, Gao Yuqing

2008, 30(5): 450-455. doi: 10.11781/sysydz200805450

Abstract(831) PDF-CN(509)

Abstract:
The West Africa coast basins are typical rift and passive margin basins which had experienced four tectonic evolution periods of pre-rift,syn-rift,transition and passive margin.Pre-salt lacustrine shale and post-salt shallow marine shale were the main source rocks in the basins.Hydrocarbon was mainly accumulated in deltaic and subfan clastics of the Tertiary rollover anticline and salt structural traps.The deep water Tertiary play of the Niger delta and salt related structures within deep and ultra deep water area in Lower Congo Basin are two areas with high hydrocarbon potential.Basins with low oil and gas exploration in the north and the south of the West Africa coast have certain hydrocarbon potential.

RESERVOIR DIAGENETIC SEQUENCE AND ITS INFLUENCE ON PORE DEVELOPMENT IN THE PALEOGENE SANDSTONES IN THE DONGYING SAG OF THE BOHAI BAY BASIN

Lu Shenqiang

2008, 30(5): 456-459. doi: 10.11781/sysydz200805456

Abstract(795) PDF-CN(306)

Abstract:
Based on the data of drilling,coring,microscopic analysis and XRD,the diagenetic sequence and secondary pore development of the Paleogene sandstone reservoirs in the Dongying Sag were stu-died.It was considered that the Paleogene sandstone reservoirs were buried more than 3 000 m and were at the stage of late diagenesis A,B and C.The influence factors of reservoir pores mainly included primary deposition,diagenesis,bioturbation and structural condition,in which sediments characters,temperature,pressure and fluid could affect the diagenesis strength to some extent.Three secondary pores zones were developed in Dongying sag as a result of actions of acid formation liquid caused by the organic matter maturation,clay minerals transformation and thermochemical redox reactions of hydrocarbon and sulfate minerals in the Paleogene sandstones in different tectonic block from late diagenesis A stage to late diagenesis C stage.

FAULT CHARACTERISTICS AND CONTROL ON PETROLEUM ACCUMULATION IN THE ZHU Ⅲ DEPRESSION, THE PEARL RIVER MOUTH BASIN

Jiang Hua, Wang Hua, Li Junliang, Lin Zhengliang, Fang Xinxin, Cai Jia, Lü Xueju

2008, 30(5): 460-466. doi: 10.11781/sysydz200805460

Abstract(855) PDF-CN(524)

Abstract:
The Zhu Ⅲ Depression in the Pearl River Mouth Basin is a halfgraben-like depression with well-developed fault system.Formation and evolution of the depression have been controlled by faults.Controlled by main faults,the depression can be divided into 9 tectonic units such as the Wenchang A Sag,among which the Wenchang A,B and C Sags are petroleum generative.Faults in the depression are mainly NEE oriented.According to combination of the main and the secondary faults,there are 4 combination styles in plane,including parallel,en echelon,broom-like and ‘Y'-like.In section,there are also 4 combination styles,including homoclinal ‘Y'-like,reverse ‘Y'-like,complex ‘Y'-like and accor-dant fault step.Faults control source rock distribution,reservoir generation and distribution as well as petroleum generation and migration.The controlling effects may be favorable or unfavorable.The main faults,especially the ‘Y'-like faults generative region,are the key targets for petroleum exploration in the Zhu Ⅲ Depression.Uplifts along the edge of the depression which are far away from oil generation center and blocked by faults should be taken as long-term targets.

THE RESERVOIR CHARACTERISTICS AND ITS PETROLIFEROUS SIGNFICANCE IN THE DEVONIAN DONGHETANG FORMATION, TAHE AREA, THE TARIM BASIN

Feng Xingqiang, Zheng Herong, Xiang Zang

2008, 30(5): 467-471. doi: 10.11781/sysydz200805467

Abstract(1225) PDF-CN(344)

Abstract:
The sandbodies of the Devonian Donghetang Formation were trended in direction of S-N in Tahe area,the Tarim Basin,with thick in the northwest and thin in the southeast.The reservoir rocks consisted of quartz sandstone,feldspathic litharenite and subarkose.The pore types of the reservoirs were mainly residual intergranular pore,intergranular dissolved pore and intragranular dissolved pore.The diagenesis of the Donghe sandstones in the area could be divided into the compaction,clay cementation,quartz overgrowth,carbonate cementation and solution.The sandstones were of middle-low porosity with a mean of 11.25% and of middle-low permeability with a mean of 23.99×10^-3μm² because of their sedimentation and diagenesis.According to the physical property and the criterion of evaluation of reservoirs,the reservoirs are sorted into three types and eva-luated respectively.It was indicated that the hydrocarbon-bearing capability of the reservoirs were controlled by sedimentary environment,lithologies and physical properties.

STUDY ON THE MIDDLE-LOWER PERMIAN SEQUENCE STRATIGRAPHY IN NORTHEASTERN AREA, THE SICHUAN BASIN

Li Fengjie, Chen Ronglin

2008, 30(5): 472-477. doi: 10.11781/sysydz200805472

Abstract(902) PDF-CN(282)

Abstract:
On the basis of sequence stratigraphic theory and the analysis of sedimentary facies,lithology and lithofacies and change of accommodation of field profile,the Middle-Lower Permian sequences stratigraphy at Yanggudong profile in Dukou town,Xuanhan County,Northeastern of the Sichuan Basin were studied.Three types,six stratigraphic sequence boundaries were discriminated.One grade Ⅱ sequence and five grade Ⅲ sequences in Middle-Lower Permian,one grade Ⅲ sequence in Liangshan Formation,two grade Ⅲ sequences in Qixia Formation and two grade Ⅲ sequences in Maokou Formation were determined.In grade Ⅱ sequence,strand swamp facies was mainly developed in lowstand systems tract,restraint platform facies or carbonate gentle slope facies in transgressive systems tract and open platform facies mainly in highstand systems tract.At the same time sequence stratigraphic framework of the Middle-Lower Permian was built.By the comparison of the change of accommodation curve and outcrop stratigraphic sequence curve,there was a very well corresponding relation between the two curves,which implied the correct of classification of the sequence stratigraphy.

BASIC CONDITIONS OF MARINE HYDROCARBON ACCUMULATION IN NORTHWEST SICHUAN BASIN-HIGH GUALITY SOURCE ROCKS

Tenger, Qin Jianzhong, Fu Xiaodong, Li Wu, Rao Dan, Zhang Meizhen

2008, 30(5): 478-483. doi: 10.11781/sysydz200805478

Abstract(805) PDF-CN(421)

Abstract:
The prospecting degree of oil and gas is low and basic research about conditions of hydrocarbon accumulation is weak.Based on comprehensive study of regional geology,conditions of hydrocarbon formation,organic geochemistry and petrology,the developmental conditions of marine hydrocarbon in the north sector of Longmenshan structural belt were discussed.There were fair source rocks for hydrocarbon generation,mainly including muddy source rocks of Qiongzhusi and Dalong Formations and carbo-nate source rocks of Qixia and Maokou Formations.But the Devonian source rocks were limited in terms of their distribution.There was no qualified source rocks in the Ordovician-Silurian.It underwent large scale of hydrocarbon migration,accumulation and late destruction in the Longmenshan belt.Ana-lysis of this process may be helpful for marine petroleum exploration.Based on geological data,it was predicted that there were favorable target zones with better exploration prospects in the thrust-nappe tectonic belt and deepest depression of the northwest Sichuan Basin.

GEOCHEMICAL CHARACTERISTICS OF THE UPPER PALEOZOIC SOURCE ROCKS IN THE SOUTHERN NORTH CHINA

Wang Rongxin, Zhao Gang, Deng Shiying

2008, 30(5): 484-488. doi: 10.11781/sysydz200805484

Abstract(715) PDF-CN(343)

Abstract:
In the Southern North China region,a series of the Late Paleozoic formation with platform facies,transitional facies and inland lake facies had been deposited.The Upper Paleozoic source rocks mostly represent a set of successive coal-bearing squence.Combined with study of the Upper Paleozoic sedimentary settings and sedimentary facies,by using analyzed and tested geochemical data,the geochemical characteristics of organic matter abundance,type and thermal evolution of source rocks in coal-bearing strata was studied.The results confirmed that the main Upper Paleozoic source rocks were contained in the coal measure mudstone and coal-bearing rock in Taiyuan Formation and Shanxi Formation.Besides that,the condition of secondary oil generation and main controlling factors(the potentiality and temperatures) of the Upper Paleozoic source rocks was considered and it was proved that the better source rocks showed greater potential,lower initial maturity and higher geothermal gradient.In the end,it was pointed out that the secondary oil generating areas were mainly in Depressions of Tanzhuang-Shenqiu,Niqiuji,Luyi,Xiangcheng.

CHARACTERISTICS OF THE SINIAN RESERVOIR BITUMEN IN WEIYUAN-ZIYANG AREAS OF THE SICHUAN BASIN AND ITS SIGNIFICANCE

Cui Huiying, Zhang Li, Wei Guoqi, Hu Guoyi, Liang Feng, Xiang Jie

2008, 30(5): 489-493. doi: 10.11781/sysydz200805489

Abstract(1017) PDF-CN(334)

Abstract:
There is large amount of bitumen in the Sinian Dengying Formation in Weiyuan-Ziyang areas,the Sichuan Basin.The occurrence of the bitumen is dominated by dissolution pore-filling and fracture pore-filling,with the intergranular-filling in the second and the micrograined disseminated-type in the least.Based on the biomarker characteristics,the bitumen can be divided into two types:one to Well Wei 117 as the representative,and the other to Wells Wei 118,Zi 1 and Zi 6 as the representative.There is a positive correlation between the reservoir property and the content and occurrence of bitumen.The reflectivity values of the bitumen are in two sections with similar evolution levels in different strata.With analysis of geological conditions,the bitumen in these areas was thought as epigenetic reservoir bitumen and sourced from oil-cracking.The content and distribution of the reservoir bitumen showed the gas source kitchen of oil-cracking gas.The occurrence,reflectivity value and biomarker characteristics showed that there were two stages of bitumen,and the second was majority while the first was minority.Based on these and the structural evolution history,the gas accumulation process was recovered.

DIRECT INDEX OF PALEOTEMPERATURE OF HIGH MATURE MARINE FACIES CARBONATE SEQUENCES-HOMOGENIZATION TEMPERATURE OF FLUID INCLUSIONS

Qin Jianzhong, Rao Dan, Jiang Hong

2008, 30(5): 494-498. doi: 10.11781/sysydz200805494

Abstract(906) PDF-CN(301)

Abstract:
Based on analyses of homogenization temperature,salinity and density of fluid inclusions in core samples from wells in the northeast of Sichuan Basin,there are 3 stages of hydrocarbon fluid activities in the region.Homogenization temperature,salinity and density of fluid inclusions are closely related.When ancient and present geothermal gradient changes are small,measured fluid inclusion homogenization temperature and palaeogeothermal gradient can be used to calculate the maximum burial depth or corrosional thickness,so as to restore thermal evolution history.Homogenization temperature of fluid inclusion,R_o,measured strata temperature and illite crystallinity are also closely related.They are direct and effective index used in thermal evolution history restoration in high mature marine facies regions.

THE OIL SOURCE AND ITS SIGNIFICANCE FOR PETROLEUM EXPLORATION IN STRUCTURAL BELTⅠIN THE HUANGHUA DEPRESSION, THE BOHAI BAY BASIN

Wang Xinhai, Su Junqing, Cao Yan, Fu Lixin, Wang Li, Xiao Mei, Guo Jinfeng

2008, 30(5): 499-502. doi: 10.11781/sysydz200805499

Abstract(740) PDF-CN(262)

Abstract:
Some stripped oil stream has been found in Dongying Formation in the Well Baidong 2×1 lying in the structural belt Ⅰ of the Huanghua Depression,the Bohai Bay Basin.The structural belt Ⅰ is large in scale with lower degree of exploration.The geochemical characters of the crude oil showed that the oil was a light and mature crude oil with middle-high content of wax.The primary gonane components are cholane and isocholestane,and the distribution of the C₂₇,C₂₈ and C₂₉ gonane is just like of an appreciably anisomerous "V".And the secondary gonane components are some diasteranes and 4-methyl gonane.The content of tricyclic terpane is appreiably lower than that of pentacyclic terpane.The content of gammacerane is high.And the content of Ts,C₂₉Ts and C₃₀ rearrangement hopanoid is higher.The distribution character of biomarkers shows that oil source is a mixture of homoneneae and terrigenous plants in brackish-saline water.This indicates that the crude oil was originated from the saline lake source rock in the lower Es1,or Es3 in the Qikou Sag.Structural belt Ⅰ is close to the petroleum generative sag,and the reservoirs conditions are good,so it's favorable for petroleum exploration.

HYDROCARBON SHOW AND CORRELATION BETWEEN OIL ND SOURCE ROCK IN THE QIANGTANG BASIN

Nan Zhengbing, Li Yongtie, Guo Zujun

2008, 30(5): 503-507. doi: 10.11781/sysydz200805503

Abstract(672) PDF-CN(368)

Abstract:
There are 4 sets of hydrocarbon source rocks in the Qiangtang Basin,including the Upper Jurassic Suowa Formation(J3s),the Middle Jurassic Xiali Formation(J2x),the Middle Jurassic Buqu Formation(J2b) and the Upper Triassic Xiaochaka Formation(T3x).Multi points of hydrocarbon show have been discovered in several locations,mainly including 3 types.The first type is the liquid oil seepage in fractures of limestone in the Upper Jurassic Suowa Formation,which was discovered at 114 Daoban,the east of Southern Qiangtang Depression.Four spots of heavy crude oil have been discovered in this area.The second one is seepage in oil-bearing dolostone,which is mainly distributed in the Middle Jurassic Buqu Formation of Longenixi area and the Upper Jurassic Suowa Formation of northern Angdaercuo area in the Southern Qiangtang Depression,and also,oil-bearing limestone and argillaceous dolomite in the Upper Jurassic Suowa Formation have been discovered in the west of the Northern Depression,Xiliangshan area.The last one is the bitumen,which is mainly distributed in the west of Northern Qiangtang Depression and the east of the central buried uplift.It is considered by comparison of geochemical methods that the liquid oil seepage of J3s limestone sources from the J3s micrite,the oil seepage of J3s and J2b oil-bearing limestones and dolostones originates from the J3s and J2x mud shale,and lots of bitumen in the Qiangtang Basin maybe originate from J3s and J2b limestone.

GEOCHEMICAL CHARACTERISTICS AND ITS EXPLORATION SIGNIFICANCE IN XIEFENGQIAO OILFIELD OF THE JIANGHAN BASIN

Luo Mingxia, Chen Bo, Xia Yongtao, Huang Famu

2008, 30(5): 508-511. doi: 10.11781/sysydz200805508

Abstract(924) PDF-CN(291)

Abstract:
Xiefengqiao Oilfield is located in the south of Wancheng fault zone in the Jiangling Sag,the Jianghan Basin.The traps were divided into two different types,i.e.Fu Ⅰ fault block and Xiefengqiao fault nose by Wancheng fault.In the early time,it was considered that Xiefengqiao reservoirs were consisted of Xiefengqiao fault nose reservoir and Fu Ⅰfault block reservoir,which were of different types and independent reservoirs.However,according to the latest production information and geochemical characteristics of the reservoirs,they were a unified reservoir.The gypsum mudstones were well developed in Xiefengqiao Oilfield.These gypsum mudstones with good plasticity were jointed with each other on both sides of Wancheng fault,so an unified seal was formed.Meanwhile,according to gas chromatography analysis of crude oils from the Neogene Xingouzui Formation of Xiefengqiao fault nose and the Cretaceous Yuyang Formation of FuⅠfault block,it can be concluded that reservoirs in Yuyang Formation in FuⅠfault block and Xingouzui Formaion in Xiefengqiao fault nose were laterally connected.They showed the same oil/water interface and the same pressure system.

THE CARBONIFEROUS SOURCE ROCKS IN WEST PART OF NORTH MARGIN OF QAIDAM BASIN AND THEIR PETROLEUM GEOCHEMICAL CHARACTERIZATION

Chen Yan, Zhang Min, Ma Lixie, Wang Yanping, Sun Kang, Zhang Guoqing, Zhang Xia, Liao Ailan

2008, 30(5): 512-517. doi: 10.11781/sysydz200805512

Abstract(739) PDF-CN(389)

Abstract:
The Jurassic petroleum system has been being the exploration target because most oils found in north margin of Qaidamu Basin are thought to sourced from the Jurassic source rocks for a long time.The Carboniferous distributed scatteredly in west part of north margin of Qaidam Basin has not been minded for the thought of poor capability of hydrocarbon generation.There are some disputes on the attribution of the stratum deeper than 4 666 m after the drilling of Well Lengke1 in Lenghu 5th structure.The stratum is the Carboniferous based on study on lithology,electricity,paleontology,and it is realized that what has been drilled to in Well Shen86,Lenghu area is also Carboniferous.Thick Carboniferous in Well Gaqiu1 drilled before Luliang Mountain in 2004 suggested the exploration perspective of the Carboniferous.It is realized that there is not only one set of source rock,the Jurassic for the discovery of the Carboniferous in the west part of north margin of Qaidam Basin.The Carboniferous and the Jurassic source rocks are very different based on their geochemical characterization.The most remarkable difference is high maturity with low abundance of disasteranes and diahopanes for the Carboniferous source rocks.The Carboniferous and the Jurassic can be distinguished well by geochemical characterization,combing with lithology,electricity and paleontology.Correlation results of oil and source indicate that some petroleum is sourced from the Carboniferous in west part of north margin of Qaidam Basin rather than all petroleum is from the Jurassic,indicating new petroleum exploration area in north margin of Qaidam Basin.

ANAEROBIC OXIDATION OF PETROLEUM COUPLED WITH REDUCTION OF URANIUM MINERALIZATION -CASES FROM DONGSHENG AND QIANJIADIAN URANIUM DEPOSITS

Cai Chunfang, Li Hongtao, Li Kaikai, Jiang Lei

2008, 30(5): 518-521. doi: 10.11781/sysydz200805518

Abstract(973) PDF-CN(272)

Abstract:
Host sandstones in Dongsheng and Qianjiadian deposits contain hydrocarbons inclusions and absorbed oils.The oils contain abundant 25-norhopanes and tricyclic terpanes,indicating that oils were heavily biodegraded.The host sandstones show intimate intergrowth of coffinite or pitchblende with secondary pyrite and carbonate cement.The pyrite is biogenic,as defined by low δ³⁴S values from -39‰ to 17‰,and from -44.5‰ to -31.40‰ in the Dongsheng and Qiajiandian deposit,respectively.The carbonate cement has carbon derived from petroleum oxidation as indicated by its δ¹³C values from -27.5‰ to 0.3‰,and from -21‰ to -4‰,respectively.The coffinite shows microorganism-like structure.Based on the data,we proposed that sulphate reducing bacteria alone or using other kinds of bacteria oxidized petroleum simultaneously and reducd sulphates and U(Ⅵ) to generate pyrite and uranium U(Ⅳ) deposits.

AN EXPERIMENTAL SIMULATION ON THE HYDROCARBON QUANTITY GENERATED UNDER PRESSURE SUPPRESSION-A CASE STUDY FROM THE JIYANG DEPRESSION OF THE BOHAI BAY BASIN

Zhang Shouchun, Zhang Linye, Zha Ming, Bao Youshu, Zhang Lei

2008, 30(5): 522-526. doi: 10.11781/sysydz200805522

Abstract(1174) PDF-CN(289)

Abstract:
Hydrocarbon generation is influenced by geologic settings such as temperature,pressure and so on.The process can be described in chemical kinetic models.Open-system and closed-system simulation experiments were used to study the kinetic characteristics of 4 kinds of main source rocks in the Ji-yang Depression,the Bohai Bay Basin.Vertical pressures equivalent to underground strata were taken into account in closed-system experiments.Some conclusions were made on the basis of the comparative analysis of the experiments.Pressure suppressed the hydrocarbon generation on different extents according to different source rocks and different evolutionary stages.With increase of the hydrocarbon generation potential of mother materials,the evolutionary degree or formation pressure,it was showed more suppression of hydrocarbon generation.The kinetic parameters of hydrocarbon generation of the source rocks related to different pressures were accordingly determined.

DEGASIFICATION METHODS AND APPLICATION OF HIGH QUALITY MARINE SOURCE ROCKS IN SOUTH CHINA

Zhang Qu, Jiang Qigui, Tao Cheng, Zhang Caiming, Ba Liqiang

2008, 30(5): 527-531. doi: 10.11781/sysydz200805527

Abstract(802) PDF-CN(305)

Abstract:
Degasification methods of adsorbed gas and acid decomposed gas in marine facies source rocks in South China are studied in this paper.GC and isotopes analyses of gas compositions are also done.The maximum relative deviation of composition contents is less than 10%,and the maximum absolute deviation of carbon isotopes is less than 1‰.Applications of the methods are studied.Coal samples are not fit for acid decomposed gas analyses.Methane isotopes of adsorbed gas generally will not be influenced by organic matter or carbonate contents.But for methane isotopes of acid decomposed gas,things are different.Acid decomposed gas is favorable for gas-source correlation.Evolution model studies of carbon isotopes of adsorbed gas and acid decomposed gas from marine facies Permian source rocks in South China are done,indicating that,as evolution degree increases,carbon isotopes of adsorbed gas and acid decomposed gas become heavier until over-mature stage.

STUDY OF THE EFFECTIVE GEOCHEMICAL EXPLORATION METHODS AND INDICATORS USED IN GOBI AREAS

Chen Zhechun, Tang Yuping, Cheng Tongjin, Jiang Tao, Huang Xin, Liu Xinhua

2008, 30(5): 532-536. doi: 10.11781/sysydz200805532

Abstract(670) PDF-CN(304)

Abstract:
An experimental study has been made by the different geochemical methods(heat-released hydrocarbon,physically absorbed gas,and wire-absorbed gas,etc) in the selected existing well(Well Chaican 1) area.The area selected for studying the geochemical methods,as well as the effective para-meters and indicators is a Gobi area in Chaiwobao,the Junggar Basin.The study of comparability and the effectiveness of the geochemical indicators in the known oil-and gas-well(Well Chaican 1) was made by the sampling collection techniques and sample testing techniques of the various geochemical methods.The results showed that the physically absorbed gas(or free gas) and the heat-released hydrocarbon could be used as the main geochemical methods in the selected Gobi area.Some indicators have halo anomaly patterns,consistent well with the existing oil and gas well(Well Chaican 1) area,such as physically absorbed gas C₂⁺ and C₄₊₅,and the acid-extraction C₁.The ratio of the physically absorbed gas,eg.iC₄/nC₄,has a apical anomaly pattern,consistent well with the known oil and gas area.

2008 Vol. 30, No. 5

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