石油实验地质

NEW IDEA ABOUT HYDROCARBON GENERATION AND POOL FORMATION

Guan Defan, Wang Guoli, Zhang Jingong, Wang Jie

2005, 27(5): 425-432. doi: 10.11781/sysydz200505425

Abstract(863) PDF-CN(568)

Abstract:
Hydrocarbon generation,migration,accumulation and diffusion loss are the products of sediments after a series of physical and chemical changes during basin formation,development and withering.The first migration of oil and gas is caused by physical field of unloading and decompression.Source rock experiences cracking and hydrocarbon expulsion at first,and then hydrocarbon expulsion and compaction,and finally compaction and hydrocarbon expulsion.Oil accumulation quantity can be comprehended as oil expulsion quantity territorially.Basin withering stage is the period of reservoir consummating and definitizing.

POLYCYCLIC EVOLUTION AND PETROLEUM ACCUMULATION IN THE WEST OF CHINA

He Zhiliang, Gu Yi, Gao Shanlin

2005, 27(5): 433-438. doi: 10.11781/sysydz200505433

Abstract(1002) PDF-CN(478)

Abstract:
Regional tectonic framework of the vast northwest area identified by 2 lithosphere fractures of Eerqisi-Deerbugan and Kangxiwa-Longmucuo-Lancangjiang is composed of polycyclic orogenic belt and ancient continental segment with different size and characteristics in the Kasakstan and Ancient China continental segments,belt-like in the south and north,block-like in the east and west.Bounded with early Hercynian movement,late Hercynian movement and middle Yanshan movement,regional tectonic framework and basin evolution can be divided into 4 cycles: the Sinian-Middle Devonian open-close cycle,under Ancient Asian Ocean environment;the Late Devonian-Middle Permian open-close cycle under Ancient Tethys Ocean environment;the Late Permian-Late Jurassic cycle under Tethys Ocean environment and the basin cycles since Cretaceous under present ocean environment.According to cycle characteristics and evolution degree,the west basins can be divided into 6 types such as mild conversion and polycyclic basin,etc.In this paper,the complicated space distribution of source generated in different stages,and the course of multi-stage hydrocarbon generation,chargement and accumulation in complicated deposition and thermal systems are discussed.The previous concept and content of multiple petroleum system are improved;a concept of petroleum accumulation unit is proposed and used in the summarization of accumulation element and course in different part of multiple petroleum system.Static condition and dynamic course of accumulation in 2 basins are analyzed based on dissection of previous reservoirs.An accumulation model is made.Petroleum accumulation in the west basins is characterized by multi-source and multi-stage.Formation,destruct and reformation of 2 types of various cause reservoirs and capping system result in sets of reservoir and cap.In different zone,types of trap compound horizontally and vertically.A general summary of "regional control of the Ancient Asia and Tethys→polycyclic basin evolution and changing superposition transformation→multi-facies oil and gas from multisource and multi-stage hydrocarbon generation→types of multiple petroleum accumulation belt in multiple petroleum system" is put forward.

THREE PALEO-OCEANS IN THE EARLY PALEOZOIC AND THEIR CONTROL TO BASINS IN CHINA

Gao Changlin, Huang Zeguang, Ye Deliao, Liu Guangxiang, Ji Rangshou, Qin Deyu

2005, 27(5): 439-448. doi: 10.11781/sysydz200505439

Abstract(999) PDF-CN(600)

Abstract:
The Late Proterozoic-Early Paleozoic ancient plate system centered by Chinese plates and the Ancient China Ocean can be described as 3 oceans and 4 lands.There are 4 big plates seperated by 3 connected oceans: the Siberia Plate(group),the Ancient Middle Asia Ocean and North China Plate group,the Ancient China Ocean and the South China Plate group,the Palaeotethys Ocean and Indian Gondwana.Formation and evolution of the Early Paleozoic basins in China during this era is influenced by ocean expansion and consumption,plate collision or construction orogenic belt and changing earth dynamics,resulting in different prototype basin evolutions.During continent parting period,rift,aulacogen prototype basin and later inner platform depression are formed.The Early Paleozoic plate is small,with typical characteristics of epicontinental basin.Epicontinental depression is important for petroleum reservation during the formation and evolution of orogenic belt.

TECTONIC EVOLUTION AND BASIN FORMATION OF THE MESOZOIC AND CENOZOIC ON THE BOTH SIDES OF QINLING-DABIE OROGENIC BELT

Ji Rangshou, Gao Changlin

2005, 27(5): 449-454. doi: 10.11781/sysydz200505449

Abstract(860) PDF-CN(452)

Abstract:
Since the Indosinian epoch,under a condensing tectonic environment compressed from3 sides,the Chinese continent has experienced 4 stages of tectonic evolution:T₃—J₂,J₃—K₁,K₂—E,and E₃/N-Q,resultingin corresponding basin prototypes along both sides of the Qinling-Dabie orogenic belt.The 1ststageis characterised by compressional intracontinental foreland basin prototype,the 2nd by compressionalintracontinental foreland and strike-slip basin prototype,the 3rd by extentional rift-subsidence basin proto-type,and the 4th by down-warped basin prototype.

POOL FORMING PATTERN AND PROCESS OF THE UPPER PERMIAN-LOWER TRIASSIC, THE PUGUANG GAS FIELD, NORTHEAST SICHUAN BASIN, CHINA

Ma Yongsheng, Fu Qiang, Guo Tonglou, Yang Fengli, Zhou Zuyi

2005, 27(5): 455-461. doi: 10.11781/sysydz200505455

Abstract(1157) PDF-CN(708)

Abstract:
As the two wells (Puguang 1 and Puguang 2) have produced a large amount of commercial natural gas from the Upper Permian Changxing Formation and Lower Triassic Feixianguan Formation in the northeast of Sichuan Basin,the Puguang natural gas field has become the biggest in the basin.The Upper Permian Changxing Formation reservoir rock is dolomite and coral shoal of platform margin facies.The Lower Triassic Feixianguan Formation reservoir rock is calcirudite shoal and ollite shoal of open shallow marine platform facies.The reservoir space is mainly dissolved pores buried late.Natural gas comes from the Lower-Middle Cambrian,Lower Permian,Upper Permian source rock.It is very important that,the Puguang paleotrap and gas pool are affected by the Yanshan and Himalayas tectonic movements.The Puguang gas pool is a structural-lithologic pore gas pool which has experienced primary oil pool stage,gas pool stage and reformation and definition stage.It is significative for exploration in the northeast Sichuan Basin.

THE EVOLUTION MODLE OF THE PUGUANG GAS FIELD IN NORTHEAST OF SICHUAN

Cai Liguo, Rao Dan, Pan Wenlei, Zhang Xinguo

2005, 27(5): 462-467. doi: 10.11781/sysydz200505462

Abstract(1061) PDF-CN(564)

Abstract:
The composition of gas in the Puguang gas field shows that methane is high and hexane,propane and heavier hydrocarbon are low,and coefficient of gas desiccation(C₁/C₁-C₅) is 0.989 6～0.999 6,clearly,the gas is the type of split gas.The oil was from the sources rocks of Lower Silurian and Permian,and formed the oil field during Late Triassic to Jurassic,The gas in the field is from the split gas of the oil field and the kerogen in the sources rock.The bitumen in the reservoirs little contributes to the gas.The reservoirs in gas field developed in the first to third secters of the Feixianguang Formation,upper Chang-xing Formation,which are the Lower Triassic and Upper Permian respectively,and the rocks are dissolved pore dolomite,doloarenite,oolite dolomite,oolite dolorudite and saccharoidal dolomite.The seal covers are mainly gyps and salt rocks,which developed in the second and fourth secter of the Jialingjiang Formation in Lower Triassic and the Leikoupo Formation in Middle Triassic,it is impotent factor to prevent the gas leak in the field.The gas field is a structure-lithology reservoir.There were three times of oil and gas migration and accumulation.The modle would be "multi-accumulation,oil spilted to gas,located in later stage".

CHARACTERISTICS AND SIGNIFICANCE OF THE CALEDONIAN KARST IN THE TAHE OIL FIELD, THE TARIM BASIN

Yu Renlian

2005, 27(5): 468-472. doi: 10.11781/sysydz200505468

Abstract(1015) PDF-CN(485)

Abstract:
The Tahe oil field is located in the Akekule uplift in the north of Tarim basin.It is the biggest carbonate hydrocarbon reservoir found in the Tarim basin up to now,and the biggest in China.According to exploration,the Ordovician reservoir,as the main reservoir bed in Tahe oil field,is mainly composed of hole,cave and aperture.Karst development consequentially controls the development of carbonate aperture-cave reservoir and reservoir formation.Kinds of data indicate that,there is Caledonian,besides Hercynian karst in the Tahe oil field.Study findings indicate that,native rock characteristics,development of rupture and fissure,ancient physiognomy,climate and water system control karst development,among which ancient physiognomy and development of rupture and fissure are the main factors.The Caledonian karst plays an important role in the development of rupture and fissure system of Ordovician carbonate rock,and is important to the exploration of middle Ordovician Yijianfang Formation,middle-low Ordovician Yinshan Formation and upper Ordovician Lianglitage Formation covered by the upper Ordovician Sangtamu Formation,consequentially enlarging the exploration foreground in this area.

ANALYSIS ON THE POTENTIAL OF HYDROCARBON RESOURCES AND EXPLORATION AND PRODUCTION IN VENEZUELAN

Xu Wenming, Ye Deliao, Chen Ronglin

2005, 27(5): 473-478. doi: 10.11781/sysydz200505473

Abstract(1475) PDF-CN(531)

Abstract:
Based on researching petroleum geology feature for petroliferous basins of Venezuelan,taking the Maracaibo and the Eastern Venezuelan Basin as an example,it is proposed that Venezuelan is a strategy area for overseas petroleum exploration and production.Venezuelan is rated as a major distribution contury of petroleum resources in the world.By analyzing the petroleum geology features and hydrocarbon accumulation conditions of the Maracaibo and the Eastern Venezuelan Basin,it suggests that the exploring should focus on the deeper of basins,where is still possible to discover huge oil and gas fields,particularly in the east part of the Maracaibo Basin,El Furrial/Quiriquire and Great Anaco petroleum provinces of the Eastern Venezuelan Basin.Therefor Venezuelan is an attractable area for petroleum exploration and production.

PETROLEUM GEOLOGICAL CHARACTERISTICS AND EXPLORATION POTENTIAL IN THE PALEOZOIC OF RUB AL KHALI BASIN, SAUDI ARABIA

Lü Xueyan

2005, 27(5): 479-483. doi: 10.11781/sysydz200505479

Abstract(1081) PDF-CN(453)

Abstract:
Petroleum geological characteristics and exploration potential have been analyzed in the Rub al Khali Basin with the theory of petroleum geology,reservoir geology and petroleum entrapment.The Rub al Khali Basin is located in the most proliferic hydrocarbon accumulation region,developing multiple reservoirs,sources and seals during the open and close of Paleo and new Tethyan oceans.The Hecynian movement plays an important role in the formation of Paleozoic traps in this basin,which in general include anticlines,faulted anticlines and structural-stratigraphic type occasionally.Although these Paleozoic traps to some degree reactivate during the formation of Zagros Mountain,they develop earlier than the main hydrocarbon migration time.Thus between them there exist better charging relationship.The Rub al Khali Basin now is in the immature exploration stage,with great potential in the Paleozoic.

PROSPECTION OF PETROLEUM GEOCHEMISTRY

Zhang Yigang

2005, 27(5): 484-489. doi: 10.11781/sysydz200505484

Abstract(851) PDF-CN(570)

Abstract:
It is reviewed in this article the progress of petroleum geochemistry in hydrocarbon generation,migration and accumulation,including: discerning technology of hydrocarbon precursors using biomarkers and carbon number distribution of alkanes,as well as the isotopic composition of alkanes;whether source rock is coal bed or mudstone in coal sequence,carbonate or mudstone in carbonate sequence;significance of amber in the Middle East oil fields;determination of maturity with FAMM technology and ring number distribution of aromatic hydrocarbons;catalytic hydrocracking technology of asphaltene and pyrobitumen for discerning their precursors;oil preservation in deep buried horizons within closed system;Proterozoic petroleum prospect in China,especially in the Ordos Basin;new idea for thermal simulation experiment of hydrocarbon generation;determination of time,temperature and pressure circumstance of petroleum migration and accumulation;possible mechanism of migration and accumulation of immature oils;simulation experiment of petroleum migration and accumulation;moving-ahead markers and lagging-behind markers for petroleum migration;and at last difficulties of petroleum geochemistry exploration on earth surface,i.e.the technology for enhancing signal versus noise ratio and reconstructing heavily tortured surface projection.

CHARACTERISTICS OF MIDDLE PALAEOZOIC MARINE SOURCE ROCK IN THE NORTH MARGIN OF MIDDLE AND UPPER YANGTZE REGION

Liu Guangxiang

2005, 27(5): 490-495. doi: 10.11781/sysydz200505490

Abstract(794) PDF-CN(529)

Abstract:
Organic geochemical researches on the Middle Palaeozoic marine profiles in the north margin of Middle and Upper Yangtze region show that the Middle Palaeozoic marine source rock mainly developed in Lower Cambrian,the bottom of Upper Ordovician Wufeng-Lower Silurian Longmaxi Formation and Permian.The Lower Palaeozoic source rock is mainly argillaceous rock with high organic abundance and is considered as the best source rock.The Upper Palaeozoic source rock is given first place to carbonate rock while making argillaceous rock subsidiary.The former belongs under the relatively good source rock with organic carbon usually being less than 1%.The latter belongs in the best source rock with high organic abundance.Types of organic matter in Permian carbonate and argillaceous source rock are many and complex with type Ⅱ₁ being of primacy.The extent of thermal evolution of these three sets of source rock is generally high with equivalent vitrinite reflectance usually being more than 2.0%.Gas is dominant in Middle and Upper Yangtze region.Research on the organic geochemical features of soluble organic matter in source rock shows that the normal alkanes in Lower Palaeozoic source rock are of frantal monopeak while that in Permian source rock hawing three types.The ratios of C₂₁ tricyclic terpans to C₂₃ tricyclic terpans and C₂₇ regular steranes to C₂₈₊₂₉ regular steranes are low in Permian source rock while those in Lower Cambrian source rock being high.In Wufeng-Longmaxi Formation source rock,the above-mentioned ratios are between the both.

RESEARCHES ON THE CHARACTERISTICS OF THE NEUTRAL NITROGEN COMPOUNDS AND THE OIL MIGRATION IN ORDOVICIAN CRUDE OIL FROM TAHE OIL FIELD, TARIM BASIN

Shao Zhibing

2005, 27(5): 496-501. doi: 10.11781/sysydz200505496

Abstract(717) PDF-CN(413)

Abstract:
In Tahe oil field,the oil accumulation formed in several stages.The heavy oil and the light oil are together in presence in the Ordovician reservoirs.In heavy oil,not only the absolute concentrations but also the ratio indicators of neutral nitrogen compounds are too low to distinguish the oil migration path.The distribution of the neutral nitrogen compounds in the light oil shows that the oil migrates from the south to the north and from the east to the west.In these two orientations,the absolute concentration of carbazole(CA) decreases,the ratio of methycarbazoles(MCA) and the dmethycarbazoles(DMCA) increases,and the ratio of benzo carbazole,[a]/([a]+[c]),decreases.At the fault belt in the No.3 Block in Tahe oil field,the absolute concentration of carbazole is high,the ratio of MCA to DMCA is low,and the value of [a]/([a]+[c]) is relative high.These features show that it is through the fault that the hydrocarbon migrates from the source rock to the reservoirs.In this way,the oil migration paths are short,and the hydrocarbon can accumulate in the late stages.Therefore,the crude oil is lighter in No.3 Block than in the blocks of No.4 and No.6 in Tahe oil field.

Qian Yixiong, Cai Liguo, Gu Yi

2005, 27(5): 502-507. doi: 10.11781/sysydz200505502

Abstract(692) PDF-CN(510)

Abstract:
The wide range variation of composition of formation water distributed in the different areas of the Taihe oilfield are likely to represent the different and complex system of fluid.Using the mapping of ion related parameters of formation water distribution in the Taihe oilfield,authors have tried to define forms and boundary of formation water system and determinate the direction of petroleum migration based on the gradient of ion related parameters.It is concluded that the distribution in the Taihe oilfield water shows a distinctly "Block form" along the N-S direction and "Zone form" in the E-W direction,i.e.,the Triassic formation water in No.1 and No.2 district of the Taihe oilfield is taken shape in E-W direction,and the "Zone form" of distribution of formation water in No.3,No.4,No.6 and No.8,as well as the Northwest part of No.7 are significantly present in the N-S direction with different variation tendency along theirs E-W wing,while the Southern platform in the Taihe oilfield suggests that variation of distribution from southeast to northeast and southwest.Besides,the distribution of formation water is locally present as isolated and closed fluid flow system in the shapes similar to cavern,barrel and other irregular forms,and it also have been found there are either intermediated zone between weak and strong water-flow movement or stagnate zone,the direction of petroleum migration is mainly interpreted as controlled from south or southwest to north or northwest in the Taihe oilfield in terms of the major ion concentration and its combined parameters.

HYDROCARBON VERTICAL MICRO-MIGRATION AND ITS GEOCHEMICAL EFFECTS IN SICHUAN BASIN

Tang Yuping, Liu Yunli, Zhao Yuewei, Chen Yingjie

2005, 27(5): 508-511. doi: 10.11781/sysydz200505508

Abstract(747) PDF-CN(528)

Abstract:
According to the characteristics of the hydrocarbons in the well profiles,the hydrocarbon vertical micro-migrating tracks can be revealed and then proceed to trace to the source of hydrocarbon anomalies near surface.This is an important method of studying the near-surface hydrocarbon anomaly patterns and forming mechanism.In the oil and gas wells in Sichuan Basin,the percentage of naphthenic hydrocarbon gradually decreased while the normal alkane and isoalkane increased from deep to surface.Moreover,the ultraviolet derivative values of 280 nm and 210 nm decreased.These clearly indicate the direction of hydrocarbon vertical migration and show that the surface hydrocarbon anomalies have relation with deep reservoir.In a gas well in west Sichuan area,the hydrocarbon chromatogram of C₁—C₅ and the 3D fluorescence chromatogram of the near-surface sample are similar to that of the reservoir sample,showing the both ha-ving the same source.

DISCUSSION ON THE KINETIC CHARACTERISTICS OF HYDROCARBON GENERATION OF DIFFERENT MACERAL SOURCE ROCKS

Jiang Qigui, Wang Qin, Cheng Qiuquan, Zhang Caiming, Liu Wenbin

2005, 27(5): 512-518. doi: 10.11781/sysydz200505512

Abstract(685) PDF-CN(486)

Abstract:
The distributions of activation energy of different hydrocarbon source rocks and the relationship between average activation energy and different macerals were discussed in this paper.Research results show that a positive correlation between maturity and average activation energy can be observed.The same is true of the content of vitrinite.The correlation between the content of lipinite and average activation energy have two kinds of trend.It is a positive correlation when the organic matters have been altered strongly by microbe,if not,there is a negative correlation.The correlation between the content of exinite and average activation energy shows a negative trend.The research confirms that activation energy of hydrocarbon source rock has many influential factors and its hydrocarbon generation principle is complicated.Algae have characteristics of inchoate hydrocarbon generation and they are important hydrocarbon sources of immature oil.The hydrocarbon source rocks which possess many kinds of maceral have characteristics of multi-period hydrocarbon generation.

NEW TECHNIQUES IN OIL AND GAS GEOCHEMICAL EXPLORATION

Qin Jianzhong, Qian Zhihao, Cao Yin, Zhang Meizhen

2005, 27(5): 519-528. doi: 10.11781/sysydz200505519

Abstract(846) PDF-CN(613)

Abstract:
The oil and gas geochemical analysis technology has gone through three processes of establishment,growing and innovation in our country since it being introduced from former Soviet Union in 1950's.The important new techniques developed in recent years are detection of light hydrocarbons in oil,gas and rock,organic geochemical methods determining the migration and covering conditions of natural gas,organo-petrologic analysis methods,reservoir geochemical analysis techniques,thermal simulating experiment technique of quadratic hydrocarbon-generation and so on.The development trends of oil and gas geochemical analysis technology mainly include paying great attention to high-speed quantitative analysis and multi-instrument on-line detection techniques,developing the geochemical analysis methods of oil-gas-water migration and accumulation,establishing the experimental analysis methods and standards on carbonate rock evaluation in the south of our country and further perfecting the analysis techniques on natural gas migration-accumulation-preservation conditions and natural gas resource evaluation.

LOOKING FORWARD TO THE POSITION AND ROLE OF SURFACE GEOCHEMICAL EXPLORATION FOR OIL AND GAS

Xia Xianghua

2005, 27(5): 529-533. doi: 10.11781/sysydz200505529

Abstract(954) PDF-CN(569)

Abstract:
In 1930's,German Laubmeyer and former Soviet Sokolov developed gas surveying method,raising the curtain on petroleum geochemical exploration.Up to now a whole series of methods and indicators have been set up so as to detect the physical,chemicalandbiologicalchanges related to hydrocarbon microseep in surface environment.The experimental analysis techniques used to detect micro petroleum information near surface have been considerably developed.The reliability of evaluating deep oil and gas prospect according to the surface geochemical anomaly has been greatly improved.The hydrocarbon-bearing interval,buried depth and scale of an oil and gas accumulation can not be accurately determined by surface geochemical exploration as yet.However,the expleration practice at home and abroad has proved that by using petroleum geochemical prospecting methods,good results in regional oil-and gas-prospect evaluation,direct detection of hydrocarbon in a trap as well as optimizing drilling targets were achieved.Surface petroleum geochemical prospecting is an effective oil and gas exploration means being supplemental to conventional petroleum geologic and geophysical methods.According to the existing research and application achievements,combining oil and gas geochemical techniques with the conventional petroleum exploration methods can play a certain role in the whole processes of petroleum exploration and development no matter in land or in ocean.Surface oil and gas geochemical exploration has characteristics and advantages of low-cost,short-period and directness.This technology will play an increasingly important role in oil and gas exploration in the coming dozens of years along with the research being deepgoing and unceasing innovation of methods.

EXPERIMENTAL STUDY ON DIAGENETIC EVOLUTION FOR TRIASSIC IN THE SONGPAN-ABA AREA

Yang Qi, Liu Weixin

2005, 27(5): 534-538. doi: 10.11781/sysydz200505534

Abstract(997) PDF-CN(449)

Abstract:
In this paper,diagenetic features have been studied and diagenetic stages identified for Triassic in the Songpan-Aba area by experimental analysis on diagenetic indicators,such as petrologic analysis on mineral facies,investigations of clay minerals and assemblage features,illite crystallinity determination colibrated to standardized scale(CIS),percent of smectite layer in mixed clay minerals,vitrinite reflectance determination,and thus help the diagenetic study of sedimentary rocks and pool forming conditions.

FEATURES OF ANOMALIES RELATED TO RESERVOIR AND ANOMALY PATTERN RECOGNITION IN INTENSIVE OIL AND GAS GEOCHEMICAL EXPLORATION

Zhao Kebin, Sun Changqing

2005, 27(5): 539-543. doi: 10.11781/sysydz200505539

Abstract(833) PDF-CN(427)

Abstract:
Intensive oil and gas geochemical exploration is a new technique recently developed by former Hefei Institute of Petroleum Geochemical Exploration.Based on the research results of the near-surface hydrocarbon compositions and their distribution characteristics acquiring through the new lighthydrocarbon detection method,the high-density sampling grid and the unconventional data-processing methods,this technique can evaluate the oil potential of a trap or the favorable areas of oil and gas accumulation.The hydrocarbon anomaly related to reservoir recognized by intensive geochemical exploration normally occurs as apical anomaly being composed of the combination of block anomaly and halo anomaly.The fabric of the light hydrocarbons is characterized by heavy inside and light outside an existing oilfield.The concentration center of the hydrocarbons,especially the heavy hydrocarbons,coincides well with deep oil and gas accumulation.In order to further improve the ability of the oil and gas geochemical exploration technique to resolve the complicated geological problems,it is proposed that,during intensive geochemical exploration,anomaly rings should be cautiously delineated while researches on anomaly characteristics should be paid more attention to.Evaluation techniques like multi-parameter geophysical and geochemical recognition,fractal theory and neural network should be used in predicting oil and gas potential.The favorable site predicted by using the 3-layer BP neural network technique to recognize the geochemical anomal patterns in HBG oilfield has been verified by the consequent drillings.This result shows that in the recognition and the evaluation of the geochemical anomaly related to reservoir,integrating hydrocarbon concentration anomaly and pattern recognition technique is feasible and effective for oil and gas potential prediction.

EXPERIMENTAL STUDY ON TRACE ELEMENT METHOD IN SURFACE GEOCHEMICAL PROSPECTING FOR OIL AND GAS

Wang Guojian, Cheng Tongjin, Wang Duoyi

2005, 27(5): 544-549. doi: 10.11781/sysydz200505544

Abstract(995) PDF-CN(539)

Abstract:
Based on confirming the existence of hydrocarbon microseepage over Xinchang gas field in west of Sichuan Basin,surface trace element survey and hydrocarbon geochemical exploration were conducted in this area.The relationship between trace elements and surface geochemical indicators with hydrocarbon microseepage were studied.Some trace elements were proved to have stability and indicative significance to oil and gas by comparing the new data with previous ones.According to multivariate statistics and combining with the effects of microseep anomaly reflected by trace elements in surface soil over the known gas field,it is thought that trace element indicators Cl,S,V,Ni,Cu,Zn,Sb,Cr,Co,Ba,Mo,Mn,Fe,Fe/Mn and V/Ni are effective for gas-prospect evaluation in this area because of the respondence to the gas field.Moreover,the geologic significance of the characteristics of trace elements anomaly was discussed.The effective indicators optimized in the known gas field are of certain directive significance and important immediate significance to perspective assessment of oil and gas in large area for the future.

2005 Vol. 27, No. 5

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