石油实验地质

STRUCTURAL CHARACTERISTICS OF THE JURASSIC BASIN IN THE WEST PART OF THE NORTHERN MARGIN OF THE QAIDAM PLATE AND THEIR EVOLUTION

ZHENG Meng-lin, LI Ming-jie, CAO Chun-chao, ZHANG Jun-yong

2004, 26(4): 315-318. doi: 10.11781/sysydz200404315

Abstract(506) PDF-CN(500)

Abstract:
The Jurassic distribution was controlled by NW-trending and near EW-trending structures in the west part of the northern margin of the Qaidam Plate.Near EW-trending structures zoned the Jurassic from north to south,and NW-trending structures divided the Jurassic into some blocks from west to east.Several thickness centers formed because of the controlling of NW-trending and near EW-trending structures.The Early-Middle Jurassic basin was an extensional faulted basin,in which major hydrocarbon source rocks were deposited.And the Late Jurassic-Cretaceous basin was a compressional basin.From the Early Jurassic to the Cretaceous,strata deposition migrated from south to north and from west to east.The deposition of the Cenozoic basin superposed on the Jurassic basin played an important role in the pre-servation of the Jurassic,and promoted oil and gas generation.Structure deformation and combination of the Cenozoic provided favorable conditions for the oil and gas pool formation of the study area.

SUPERIMPOSITION AND MODIFICATION OF THE MESOZOIC AND PALEOZOIC BASINS AND MULTI-STAGES OF HYDROCARBON ACCUMULATION WITH MULTIPLE SOURCE ROCKS IN LOWER YANGTZE AREA

GUO Tong-lou

2004, 26(4): 319-323. doi: 10.11781/sysydz200404319

Abstract(515) PDF-CN(536)

Abstract:
Lower Yangtze area is a superimposition basin modified by multiple tectonic movement.It showed complicated structural pattern as a result of existence of two tectonic mechanisms and two generations of basins.Four typical oil and gas fields,such as Zhujiadun gasfield,indicated that a large scale of hydrocarban generation,migration and accumulation were occurred during Mesozoic and Paleozoic.There are reservoirs with multiple sources and repeatedly accumulation in the area.The area with Upper Paleo-zoic and Mesozoic geological bodies and good preservation condition is potential target for petroleum exploration.

PETROLEUM EXPLORATION OF THE SLOPE BELT IN THE GRABEN BASIN-A CASE STUDY OF THE DONGYING SAG

SHANG Ming-zhong, LI Xiu-hua, WANG Wen-lin, FU Jin-ping

2004, 26(4): 324-327. doi: 10.11781/sysydz200404324

Abstract(610) PDF-CN(467)

Abstract:
The slope belt in the south of Dongying Sag is a typical graben-like depression.During the 30 years of exploration,10 oil-and-gas fields have been discovered.By analyzing the relationship among tectonic setting,sedimentary system and reservoir formation,it is deemed that,there exists close relationship between the large-sized successive normal structure,high system tract and the distribution of hydrocarbon reservoir.And then,the reservoir types and the crude properties of this kind of slope zone,from the edge to the center of the subsag,are summarized.The inspiration,from exploration of the slope belt in the Dongying Sag,is very important for such oil-and-gas exploration of the slope belt in the graben basin.

ANALYSIS OF THE TYPES OF OIL AND GAS TRAPS IN THE WEST SICHUAN DEPRESSION

TANG Li-zhang, CAO Lie, AN Feng-shan

2004, 26(4): 328-332. doi: 10.11781/sysydz200404328

Abstract(656) PDF-CN(517)

Abstract:
In the West Sichuan Depression with tight sand,the formation mechanism of traps and gas reservoir is quite complicated,resulted from the basin's complex evolution.Even in different structural part or horizon of the same structural deformation band,there exists distinct difference in both oil-and-gas bearing condition and geological factors restricting trap and gas enrichment.There are structural traps where structural activities enrich oil and gas.There are also non-structural stratum and lithologic traps,such as palaeostructural-lithologic trap,palaeostructural-diagenetic trap,and structural-lithologic trap,where structural activities cooperate with lithology,lithofacies,and sedimentary environment.

ANALYSIS ON SEQUENCE STRATIGRAPHY AND DEPOSITIONAL SYSTEMS OF THE CARBONIFEROUS IN WEST MANJIAER REGION

JIANG Xiao-qiong, GUO Jian-hua, GUAN Hong-lin, RAO Dan, CHEN Ben-cai

2004, 26(4): 333-337. doi: 10.11781/sysydz200404333

Abstract(665) PDF-CN(507)

Abstract:
Based on the comprehensive using of outcrop,borehole,logging and seismic data and the boundary characteristics of depositional system tracts,the Carboniferous of West Majiaer area,Tarim Basin were divided into six sedimentary sequences.And development of the lowstand,trangressive and highstand system tracts was ascertained.The study area was located on the continental shelf during Carboniferous.The major depositional systems were composed of 1) river system;2) littoral system;3) shallow marine shelf system;4) shallow carbonate system;5) fan-deltaic system;6) coastal plain system;7) lagoon system;and 8) mixed clastic-carbonate system.Lowstand system tracts were characterized by river system;and shallow marine shelf,shallow carbonate platform,coastal plain and mixed clastic-carbonate systems were developed in trangressive system tracts.Except for river system,all other systems were developed in highstand system tracts.The reservoirs were mainly developed in the littoral system of highstand system tracts.

STUDY ON THE CHARACTERISTICS OF PETROLEUM SYSTEMS IN BURIED-HILL TRAPS

GAN Hua-jun, WANG Hua, HAN Jin-yang, CHEN Liang, YAN De-tian

2004, 26(4): 338-343. doi: 10.11781/sysydz200404338

Abstract(565) PDF-CN(472)

Abstract:
As we know,the geologic background of buried-hill traps is very intricate,and the study and exploration of buried-hill oil pools are quite difficult.The paper discussed the characteristics and complexity of buried-hill traps and analyzed the elements of buried-hill trap petroleum systems and their action processes based on the conception of petroleum systems.According to the contrast of formation time between source rock strata and buried-hillbasement and spatial-matching relationshipbetween them,three petroleum system or subsystem models of buried-hill traps were suggested,that is,the new source-old reservoir type,the old source-new reservoir type and the old source-old reservoir type.Associated with the examples and based on the three models,the authors also analyzed the characteristics of single and compound petroleum systems,discussed the methods of description and exploration and suggesed the ways of work.This would be of important theoretical and practical significance to the study and exploration of buried-hill pools,and also can be used as references for the study of petroleum systems in other known oil-pool traps.

PETROPHYSICS AND EVALUATION OF THE KALASHAYI FORMATION, TAHE OILFIELD

WEI Fu-jun, HE Fa-qi, PU Ren-hai

2004, 26(4): 344-348. doi: 10.11781/sysydz200404344

Abstract(588) PDF-CN(335)

Abstract:
Although the Carboniferous Kalashayi sandstone reservoirs of Tahe Oilfield in Tarim Basin are buried at the depth of 4 800-5 200 m,they have fairly good petrophysical property.The porosities range generally from 8% to 12%,with the maximum of 20%;and the permeabilities vary typically from 10×10^-3 to 100×10^-3μm²,with the maximum of over 1 000×10^-3μm².Mercury injection data indicate that,the reservoir is characterized by medium-pore-coarse-throat structure with coarse skew in pore size distribution.Thin sections with blue epoxy impregnation and electron microscope scanning photograph show that' the main pore types are intergranular and intragranular pores from dissolved feldspar and residual original intergranular pores,while the smaller part of porosity is contributed by interstitial microcrystalline to very fine crystalline limestone intercrystalline pores and fissure pores.It is obvious that the depositional facies and distance from the source area affect porosity and permeability which increase conspicuously approaching to source area along with the enhancement in quantity and thickness of channel sandstones.The present reservoir prediction is still mainly relied on sand bodies forecast by means of analysis of seismic data and depositional facies due to the lack of method for spatially predicting the dissolution of feldspars.

ANALYSIS ON THE UPINTRUSION OF THERMAL FLUID AND THE MIGRATION AND ACCUMULATION RULES OF NATURAL GAS AND CO₂ IN THE MUD DIAPIRS OF THE YINGGEHAI BASIN

HE Jia-xiong, XIA Bin, LIU Bao-ming, ZHANG Shu-lin

2004, 26(4): 349-358. doi: 10.11781/sysydz200404349

Abstract(783) PDF-CN(447)

Abstract:
The Yinggehai Basin is a Cenozoic high-heat basin developed on the passive continental margin of the northern part of the South China Sea.Its high geotemperature field and high geothermal flux are mainly concentrated in the mud-diapir structural zone of the Yinggehai Depression in the central part of the basin.So,the upintrusion of thermal fluid in the mud diapirs,especially the thermal fluid action in the late stage controlled the migration,accumulation and enrichment rules of natural gas and CO₂.Meanwhile,the local intrusion of thermal fluid by different layers,different blocks and different districts resulted in the migration,accumulation and enrichment differences of crust-sourced CO₂ and hydrocarbon gases and the characters of local enrichment by different layers,different blocks and different districts.In a word,the upintrusion of thermal fluid in the mud diapirs was the key factor controlling the migration and accumulation of natural gas and CO₂.According to the geochemical characteristics of CO₂ and hydrocarbon gases and their controlling factors,the migration and accumulation rules of CO₂ and hydrocarbon gases can be analysed and predicted.This will provide decision basis for the exploration of natural gas.

GEOCHEMICAL CHARACTERISTICS OF HYDROCARBONS IN CRUDE OILS FROM THE QAIDAM BASIN

DUAN Yi, WANG Zhi-ping, ZHANG Hui, WU Bao-xiang, WANG Chuan-yuan, MENG Zi-fang, ZHANG Xiao-bao, ZHOU Shi-xin

2004, 26(4): 359-364. doi: 10.11781/sysydz200404359

Abstract(546) PDF-CN(483)

Abstract:
The Qaidam Basin is an important Mesozoic-Cenozoic petroliferous basin in west China.18 oil fields have been found in the western and northern Qaidam Basin since oil was first discovered in the late 1950s,and the western Qaidam Basin contains more oil fields compared to the northern Qaidam Basin.Geneses of crude oil in these 2 areas are significantly different.Hydrocarbon biomarkers in 16 crude oil samples from 13 oil fields of the 2 areas are analyzed and their geochemical characteristics are studied.The distribution and composition of biomarkers indicate that,crude oils in the western area originated from source-rocks under weak oxidation and freshwater-marsh lacustrine environment.Crude oils in the western area derived mainly from bacteria and algae;however,those in the northern area from terrestrine high plants.According to the characteristics of biomarkers and the compositions of carbon isotope,crude oils in the Qaidam Basin can be divided into 2 genetic groups and 7 genetic subgroups.

EXPERIMENTAL INVESTIGATION ON VARIATION OF GEOCHEMICAL COMPOSITIONS OF NATURAL GAS DURING DIFFUSION UNDER STRATIGRAPHIC CONDITION

MA Li-yuan, ZHANG Xiao-bao, LI Jian, YAN Qi-tuan, LI Xiu-fen, SONG Cheng-peng

2004, 26(4): 365-369. doi: 10.11781/sysydz200404365

Abstract(579) PDF-CN(482)

Abstract:
In order to study the geochemical characteristics of natural gas during diffusion,an experimental simulation under stratigraphic condition (70 ℃,8 MPa) has been performed on a solid sample.During the diffusion of natural gas,the relative percentage of methane in reservoir gas gradually decreases,but the relative percentages of ethane and propane increase correspondingly.The diffusive gas shows the same compositional varying tendency as the reservoir gas,but the relative percentage of methane in diffusive gas is higher than that in reservoir gas at the same time,and the relative percentages of ethane and propane in diffusive gas are lower than those in reservoir gas.These phenomena are all caused by stratigraphic chromatographic effect.The relative percentage of normal butane in reservoir gas is higher than that in diffusive gas at the same time,and the relative percentage of isobutane in reservoir gas is lower than that in diffusive gas.This is also the result of stratigraphic chromatographic effect.The C₁/(C₂+C₃) and iC₄/nC₄ values may be used as the geochemical indexes of natural gas migration.There exist a logarithmic linear correlative relation between the relative percentage of compositions of reservoir gas and the diffusive gas percentage and a quadratic relation between the relative percentage of compositions of diffusive gas and the diffusive gas percentage.These relations may be helpful for calculating the amount of diffusive gas,evaluating the reservoir gas resource prospect,deeply understanding into the variation of compositions of natural gas during diffusion and predicting the total resources of natural gas derived from the same source rock but preserved in reservoirs with different ages.

GENETIC ANALYSIS OF THE HIGH MATURATED BITUMEN IN SONGPAN-ABA AREA

JIN Ju-chang, QIN Jian-zhong, ZHANG Zhi-rong, FAN Min, ZHANG Qu

2004, 26(4): 370-374. doi: 10.11781/sysydz200404370

Abstract(506) PDF-CN(523)

Abstract:
Based on genetic analysis of the Silurian bitumen from Yaogou and Devonian bitumen from Dangduogou in Songpan-Aba area,it was indicated that these bitumen samples were high maturated solid bitumen which sourced from the Silurian or Cambrian mudstones.They were the relict of the old oil pools which were destructed during the Early Hercynian movement.Formation of the bitumen was very complex.It might be the result of co-activity of cooling metamorphism and debitumination.Hydrocarbon could be generated from the bitumen as they were deeply re-buried.

EXPERIMENTS ON PETROLEUM GENERATION-CONSIDERATIONS AND OUTLOOK

ZOU Yan-Rong, SHUAI Yan-hua, KONG Feng, PENG Ping-an

2004, 26(4): 375-382. doi: 10.11781/sysydz200404375

Abstract(659) PDF-CN(650)

Abstract:
The study of petroleum generation,based on pyrolysis experiments and by means of reaction kinetics,is a systematical method combined closely with geologic conditions.Based on the summarization of present works on pyrolysis and kinetics,the outlook and prospects were discussed in this paper,and some conclusions and aspects worthy to further studies were proposed:1) up to date,hydrous pyrolysis was one of the best technique for simulating oil formation,and the confined system pyrolysis was still an excellent experiment technique of oil and gas generation/cracking and can be used to carry out hydrous pyrolysis experiments;2) the pyrolysis equipment with the episodic expulsion of hydrocarbon remained to be deve-loped;3) it was sure that pressure affected organic matter maturation,hydrocarbon generation and oil cracking,but the effects were possibly different;4) the kinetic study based on the pyrolysis experiments at single heating rate would not be accepted in the future;5) the kinetic models with the effects of pressure,including hydrocarbon generation and stable isotopic modelling,were expected in further studies;6) most geologic catalysts,except water-soluble,had few influences on oil and gas formation,but they possibly affected petroleum cracking in reservoirs;7) natural gas components and isotopic composition were closely related to accumulation history,to which much attention was expected to pay;8) the study of inorganic matter and its hydrous pyrolysis and the kinetics of non-hydrocarbon gas generation and isotopic evolution were of potential values for scientific research.

PHYSICAL SIMULATION EXPERIMENT AND EXPLANATION OF GAS ACCUMULATION MECHANISM IN THE DEEP BASIN GAS ACCUMULATION REGION AND ITS HIGH-PERMEABILITY SAND BLOCK

MA Xin-hua, WANG Tao, PANG Xiong-qi, JIN Zhi-jun, LUO Qun, WANG Qiang

2004, 26(4): 383-388. doi: 10.11781/sysydz200404383

Abstract(659) PDF-CN(554)

Abstract:
Physical simulation experiment indicates that,pressure of the deep basin gas accumulation and its high-permeability gas-rich zone are not invariable,but change periodically with the geologic conditions (gas providing intensity and quantity).During the construction period of deep basin gas accumulation,the high-permeability gas-rich zone of deep basin gas accumulation and the compact sand body around form 2 independent positive pressure systems respectively,due to the permeability difference between them.During the dispersing period of deep basin gas accumulation,both pressure system decrease to negative pressure state and become an united pressure system.The evolution is of the characteristics of sinusoidal curve.Negative pressure is not the basic charateristic of deep basin gas accumulation,but one characteristic of the dispersing period during the formation and evolution of deep basin gas accumulation.The formation and evolution of deep basin gas accumulation experience 6 stages:gas entrance,critical touching time,"dessert" fornning,connection of 2 gases,expansion of gas accumulation,and adjust-mix.The controlling forces include gas expanding force,capillary pressure and buoyancy,which play different roles during different stages.Thus,relatively complete accumulation succession and mechanism model of deep basin gas accumulation and its high-permeability gas-rich zone under physical laboratory condition are established.

GENESIS AND PETROPHYSICAL IDENTIFICATION OF RELATIVE HIGH PERMEABILITY OF SANDBODY IN SULIGE GAS FIELD, ORDOS BASIN

ZHU Yi-xiang, TIAN Chang-bing, YU Xin-he, HE Dong-bo, JIA Ai-lin

2004, 26(4): 389-393. doi: 10.11781/sysydz200404389

Abstract(833) PDF-CN(464)

Abstract:
The key problem for developing the Sulige gas field with high efficiency is the identification of the relatively high permeability of sandbodies in low efficient gas reservoirs.In Sulige gas field,with the characteristics of typical coal measure strata,many primary pores have disappeared due to severe diagenesis.As a result,the relatively high permeable sandbodies are mainly developed in coarse sandstone facies with secondary pores.It is known that different log curves,such as density log and acoustic log,reflect different pore structure and lithofacies.Based on this,an interpretation model of secondary porosity index for the reservoir is established.After the calibration with the core lithology of key wells,the sensitive logs to lithology,such as GR,PE,and DEN are used to identify lithofacies by utilizing cluster analysis.The results show that the relatively high permeable sandbodies identified by this log interpretation model of secondary pores and lithofacies are consistent with core analysis and production capacity tests of gas wells.

INDOOR SIMULATION AND THERMOLUMINESCENCE RESPONSE OF HYDROCARBON MIGRATION

ZHENG Gong-wang, REN Xiu-sheng, TIAN Zhao-yu

2004, 26(4): 394-396. doi: 10.11781/sysydz200404394

Abstract(483) PDF-CN(360)

Abstract:
Based on the theory of hydrocarbon exploration by thermoluminescence (TL),it was considered that the formation of radioactivity abnormal areas over oil and gas pools was related to hydrocarbon migration.By thermoluminescence determination on ground sandy soil,this kind of abnormal areas with weak radioactivity can be effectively discovered,and the corresponding underground oil and gas pools can then be found.In order to further prove the reliability of the theory,an indoor simulation experiment was designed especially.The results revealed that 1)hydrocarbon migration can be going on under the condition of normal temperature and pressure by means of gaseous diffusion,2)sample oil also generated thermoluminescence signals,and 3)the thermoluminescence signals generated from hydrocarbon were enhanced on the top of diffusion layers.

STUDY ON THE DYNAMIC MICROMODEL OF RESERVOIRS

XU Shou-yu, LI Wei-cheng

2004, 26(4): 397-400. doi: 10.11781/sysydz200404397

Abstract(719) PDF-CN(402)

Abstract:
In long-term waterflooding developed oilfields,the long-term immersion and displacement of developing fluid to reservoirs made minute spaces connecting multiple micropores with porethroats dynamically changed,and rock framework,porethroat network and clay mineral also changed dynamically.These changes affected the distribution of underground residual oil.Aimed at the delta reservoirs in the 8th sand formation of the Sha-2 Member in shengtuo oilfield,a dynamic micromodel of reservoirs was established from rock framework,porethroat network and clay mineral three respects,and the relationship between microchanges and residual oil studied.It was suggested that these changes were dynamic and continuous,and made the distribution of residual oil further complicated.

APPLICATION OF SEISMIC INVERSION TO THE PREDICTION OF BURIED-HILL OIL RESERVOIRS-AN EXAMPLE FROM THE EAST HUANGHUA DEPRESSION

YANG Fei, PENG Da-jun, TANG Shi-qiu, XU Yan-gang

2004, 26(4): 401-403. doi: 10.11781/sysydz200404401

Abstract(526) PDF-CN(416)

Abstract:
The formation of oil reservoirs in buried hills is very complex.This makes it difficult to confirm oil-play distribution.While studying buried hills in the East Huanghua Depression,the authors suggested a new way to find out oil plays.First,the logging response characteristics of an oil play were used to synthesize the characteristic curves.Then,the comprehensive seismic reservoir characteristic inversion restrained by wells was done to obtain the seismic inversion body of the oil play.At last,by geological ana-lysis,the oil play was recognized directly from the inversion body,and the distribution range of oil pools was determined.This will provide geological bases for the development of oilfields.

HYDROCARBON HISTORICAL ORIGIN HYPOTHESIS

LI Hua-dong

2004, 26(4): 404-408. doi: 10.11781/sysydz200404404

Abstract(591) PDF-CN(499)

Abstract:
In this paper,by combining elements,galaxies,the earth and the original and evolutionary history of organism with the original and evolutionary history of hydrocarbon,it was considered that hydrocarbon began to generate after the occurrence of carbon and hydrogen elements in the cosmos,and evolved till present,that is,the formation of hydrocarbon can be traced back to the astronomical period and can continue to the geologic period even the humane period.In no matter which oil-generating hypothesis,hydrocarbon cannot be formed without hydrocarbon antecedent matter or hydrocarbon-generating original matter.Hydrocarbon antecedent matter is organic matter of various sources,including lipin,protein,carbohydrate,lignin,hydrocarbon and the material needed by the synthesis of carbon and hydrogen elements.It was suggested that hydrocarbon antecedent matter was formed before the formation of life,accompanying the evolution from elements to inorganic matter to galaxies,the evolution from inorganic matter to simple organic matter and the evolution from simple organic matter to life origin.The hydrocarbon resource eva-luation system should be based on the hydrocarbon historical origin hypothesis.

2004 Vol. 26, No. 4

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