2006 Vol. 28, No. 2

Display Method:
2006, 28(2): 90-90. doi: 10.11781/sysydz200602090
Abstract:
TWO PALAEO-OCEANS AND SEDIMENTARY BASINS DURING MESOZOIC ERA IN CHINA
Gao Changlin, Ye Deliao, Huang Zeguang, Ji Rangshou
2006, 28(2): 95-102. doi: 10.11781/sysydz200602095
Abstract:
The Tethys Ocean is composed of the Bangong Lake-Nujiang Small Ocean and Yarlung-Zangbo Main Ocean,as well as the Lhasa small blocks in the West China.The evolution of Tethys can be divided into 5 stages.1)Rifting stage(P);2)Spreading stage(T-J2-3).3)Closing stage of Bangong Lake-Nujiang Ocean(J2-3-K1).The Lhasa blocks drifted to the north.The Bangong Lake-Nujiang Ocean closed from east to west.At the same time, the Lhasa blocks cottaged to the Asian Massif.4)Subduction stage(K1-E2).The Yarlung-Zangbo Main Ocean Basin subducted to the north.The Gangdese continental margin volcanic island and the Xigaze fore-arc flysch were formed.It was changed from passive margin sedimentation(K2-3) to relict platform shallow sea deposition(E1-E22) in the Himalayan area.5) Collision stage(E23-Q).The Indian Massif and the Asian Continent collided,influencing the West China.Intracontinental foreland basin as well as pull-apart basin were formed.There did exist a Mesozoic Tethys Ocean in the South China Sea.The fauna had the same characteristics as the Pacific fauna.It is illustrated that,the Tethys Ocean was connected with the Pacific Ocean.The NE South China Sea was connected with the West Pacific Ocean.Tectonic evolution of the continental margin of SE China in the Mesozoic is stated as follow.1)The subduction stage of the Palaeo-Tethys(T2-J2).The oceanic crust subducted into the Asian Continent and paralleled displacement along transfer fault in N-S direction.The eastern margin of Asian Continent was accreted.It is pointed out that,the oceanic basin was part of the Palaeo-Tethys extending directly.2)Great changes have taken place since the Late Jurassic in the East part of China.The Pacific Ocean was formed by the expansion of three conjunction points in 185 Ma.The Kula Plate(J3-K1) moved to the north and subducted to tie NE Asia.Micro-massifs were collaged.Clino-subduction along the S-N transfer fault and micro-massifs took place in the South China and Taiwan.The subuducted accreting orogenic belt in Sikhote-Alin-SW Japan-Ryukyu Islands-Middle Taiwan and the volcano-magmatic belts in South China were formed.Rifting basins and pull-apart basins were formed.
STRUCTURAL CHARACTERISTICS OF THE CENTRAL UPLIFT BELT OF THE DONGYING SAG, THE BOHAI BAY BASIN
Ma Lijuan, Zheng Herong
2006, 28(2): 103-108. doi: 10.11781/sysydz200602103
Abstract:
Faults development is the main characteristic of central uplift belt in the Dongying Sag of BohaiBay Basin.Structural features of the central uplift belt have been investigated by basin analysis and accommodation zone theory,indicating that,uplift forming has been controlled by the second grade faults,local structure has been controlled and complicated by the third and forth grade faults,and oil-gas accumulation level has been controlled by the combination features of faults.Seismic and log data,coherence technology and wavelet transformation are presented to interpret faulted block,resulting in the method of complicated fault block oil-gas pool study,description as well as forecast,proved effective in exploration and development practice.
STUDY OF CONTROL MECHANISM OF OIL AND GAS BY THE TRANSFER ZONE IN THE GAOYOU SAG OF THE NORTH JIANGSU BASIN
Li Yahui
2006, 28(2): 109-112. doi: 10.11781/sysydz200602109
Abstract:
Transfer zone is a kind of adjusted structure to keep the conservation of deformation during the evolution of rift-basin.It exists in extensional tectonic system as well as in strike-slip tectonic system.The transfer zone in each system has different control mechanism of oil and gas.The transfer faults in extensional tectonic system have better seal capacity than that in strike-slip tectonic system.So it requires heavy-mud contents in corresponding wall to form a pool for a transfer fault related to strike-slip tectonic system.The paper has applied the theory of transfer zone to study the reasons of success and failure of exploration in the Zhenwu and the Wubao fault zone of the Gaoyou Sag,and concludes that Xuzhuang area has better seal capacity for developing extensional tectonic system than that in Chenbao area for developing strikeslip tectonic system.It helps to reveal the essence of hydrocarbon accumulation mechanism in the given area.All in all,the theory of transfer zone can greatly promote the further exploration and development of the area,and also can promote to choose advantageous traps of exploration.
PETROLEUM SYSTEM OF THE BAISE BASIN, GUANGXI PROVINCE
Wang Lianjin, Wu Chonglong, Li Shaohu, Mao Xiaoping, Li Xing
2006, 28(2): 113-116. doi: 10.11781/sysydz200602113
Abstract:
The Baise Basin in Guangxi Province is a Tertiary fault-depressed hydrocarbon basin of continental facies developed in the Triassic basal of marine facies.The essential elements of petroleum system(from source to trap) are thoroughly studied,and then ‘four charts and one table' are illustrated to express the basin explicitly so as to help further hydrocarbon exploration and development.There are two sets of source rocks,namely the Nadu Formation and the Baigang Formation,with fine reservoir and(caprocks,) forming good assemblage of generation,reservation and capsulation,yet the tectonic activities subsequently reconstructed the basin preservation greatly,therefore hydrocarbon exploration in the basin is far from satisfaction.
FORMATION AND DISTRIBUTION OF SUBTLE RESERVOIRS IN THE SOUTHERN STEEP SLOPE ZONE IN THE BIYANG SAG OF THE NANXIANG BASIN
Wen Zhixin, Wang Hongman, Chen Chunqiang, Hu Yong, Li Hui
2006, 28(2): 117-122. doi: 10.11781/sysydz200602117
Abstract:
The southern steep slope zone in the Biyang Sag of the Nanxiang Basin,is characterized by various categories of subtle hydrocarbon reservoirs.In Shuanghe area,the updip pinch-out sandstone reservoir and the fault-lithologic reservoir dominate over others.In Zhaowa-Anpeng region,the updip pinch-out reservoir and the lenticular turbidite reservoir are the major categories.In Xiaermen area,the fault-lithologic reservoir precedes.Near the large boundary faults,a small quantity of the unconformity reservoir and the buried hill bedrock reservoir have also been drilled.The formation and distribution of subtle reservoirs in this region are controlled by various factors,such as the palaeotectonic setting,the migration pathway of hydrocarbon and the source-reservoir-caprock assemblage,of which the fault as a migration pathway of hydrocarbon is the major factor to control the hydrocarbon occurrence.It is significant for the oil and gas exploration to recognize the hydrocarbon-forming model and its primary controlling factor in different area.
THE RESERVOIR-FORMING CONDITION AND ENRICHMENT RULE OF THE NATURAL GAS IN THE DONGPU DEPRESSION, THE BOHAIWAN BASIN
Su Hui, Qu Liping, Zhang Jinchuan, He Feng, Wang Pingxia, Wang Min, Wang Qi, Mu Xiaoshui
2006, 28(2): 123-128. doi: 10.11781/sysydz200602123
Abstract:
There are two types of gas source rocks in Paleogene and Upper Paleozoic in the Dongpu Depression,the Bohai wan Basin.The distribution of the natural gas reservoirs are controlled by the center of hydrocarbon generation.The accumulations of the natural gas are controlled by the tectonic characteristics.The salt rock and thick mud rock are propitious to the preservation of the natural gas.Source bed,reservoir and cap rock determine the natural gas's subsection characters in portrait.The high abnormal pressure and secondary pore zone in depth are important conditions of the natural gas enrichment and high yield.There are two reservoir-forming modes of the natural gas in the Dongpu Depression,i.e.Upper Paleozoic coal-formed gas and Paleogene condensate gas.They are characterized by the later period and episodic reservoir-forming.The residual resources of the natural gas is bigger at present in the Dongpu Depression.It is an important exploration area of the natural gas in the eastern China.The Upper Paleozoic coal-formed gas and Paleogene condensate gas is the stress in the future.
CONFIGURATION RULE OF SOURCE ROCKS AND MIGRATION SYSTEM——AN EXAMPLE FROM THE LINNAN SAG IN THE JIYANG DEPRESSION OF THE BOHAIWAN BASIN
Wang Ke, Zha Ming, Wu Kongyou, Zhang Jinfang
2006, 28(2): 129-133. doi: 10.11781/sysydz200602129
Abstract:
The configuration of source rocks and transportation system can be divided into three types of vertical contact,lateral contact and staggered contact according to their contact relationship,and can also be divided into three types of source rocks-fault,source rocks-connected sand bodies and source rocks-unconformity according to different hydrocarbon migration system. The control factors forming different combination and important effects on configuration rule of hydrocarbon source rock and transportation system were summarized.In different configuration combination,there are some difference on hydrocarbon migration fashion,migration efficiency and forming-pool types,which made different characteristic of spacial distribution of oil and gas.The configuration between source rock and fault controlled vertically dominant petroleum migration in central up-lift belt of the Linnan Sag,the Jiyang Depression of the Bohawan Basin.The configuration between source rock and connected sand bodies controlled laterally dominant petroleum migration in the Xiakou fault zone of the Jiyang Depression.
DISTRIBUTIONS OF THE MAIN MESOZOIC HYDROCARBON SOURCE ROCKS IN THE QIANGTANG BASIN OF THE QINGHAI-TIBET PLATEAU
Qin Jianzhong
2006, 28(2): 134-141. doi: 10.11781/sysydz200602134
Abstract:
Qiangtang Basin in Qinghai-Tibet plateau is a Mesozoic marine residual basin.Geologic survey and analysis of the hydrocarbon source rock samples show that there are four hyddrocarbon source rocks longitudinally developing in T3x,J2b,J2x and J3s formations in Qiangtang Basin.The main hydrocarbonsource rocks in the different depressions or sags are different.The hydrocarbon source rocks develop in J3s,J2b and J2q-T3x formations in the east of South Qiangtang Depression and in J2x,J2b and T3x formations in the centre and west of South Qiangtang Depression.In North Qiangtang Depression,the hydrocarbon source rocks develop in T3x and J2b formations in the east and in J2x,T3x,J2b and J3s formations in the west.The thicknesses of the effective Jurassic muddy hydrocarbon source rock and carbonate hydrocarbon source rock are generally 100 to 500 meters and 200 to 600 meters,respectively.There are hydrocarbon-rich rocks with 200 to 400 meters thick devceloping in J2x and J3s formations.The thickness of the good-quality hydrocarbon source rock developing in T3x formation is generally 500 to 700 meters.And in North Qiangtang Depression,100 to 300 meters thick of good-quality hydrocarbon sourck rock developing in T3x formation.The maxima of residual TOC of the J2x shale,J3s marl and T3x shale are 4.15%,1.26% and 1.5%,respectively.However,the values of residual TOC of the J2x gray and gray-green mudstone as well as J3s and J2b limestone are mostly less than 0.5% and 0.2%, respectively.The value of residual TOC of the T3x marine shale is generally in the range of 0.5% to 1%.
KEY EPISODES OF PETROLEUM MIGRATION AND ACCUMULATION IN THE SOUTHWEST EDGE OF JIANGHAN BASIN
Wang Xueling, Liu Zhongrong
2006, 28(2): 142-146. doi: 10.11781/sysydz200602142
Abstract:
According to analysis of geochemical features of nitrogen compounds in crude oil, petroleum migration direction in the southwest edge of Jianghan Basin is from the main petroleum-generating depression(the Meihuaiqiao Depression) in the north to the Fuxinchang,Caixue Belt in the south.With techniques such as fluid inclusion,laser Raman spectrum and micro-fluorescence analysis,it is studied the episodes of oil pools formation.There are two episodes for petroleum to entrap: the first one is the early period of Jingsha Formation of Lower Tertiary,the second one is the medium-late period of Qianjiang Formation of Lower Tertiary. Three patterns to form oil-pools are put forward: the Inner Source-Nose-Like Fault-Facies-Controlled(self-generated and self-stored),the Inner Source-Nose-Like Fault-Fault-Controlled(generated in the lower section and stored in the upper section) and the Marginal Source-Faulted Block-Fracture and Facies-Controlled.
RESERVOIR FORMING CHARACTERISTICS AND GEOLOGIC RISK EVALUATION OF THE BURIED HILL TRAPS IN THE JIYANG DEPRESSION OF THE BOHAIWAN BASIN
Wang Youqi, Tang Dazhen
2006, 28(2): 147-151. doi: 10.11781/sysydz200602147
Abstract:
There are mainly three types of the buried hill traps in the Jiyang Depression of the Bohai wan Basin.They are fault block,hammock and internal types of buried hill trap with different reservoir forming chacteristics.Different geologic conditions play a different role on the buried hill trap reservoir forming.When five evaluation conditions and weight coefficient of each gelogical element were researched,the difference and the actual features of Jiyang depression should be fully reflected.Hierarchical evaluation criteria may be established by applying the methods of drilling success ratio hierarchy,cumulative probability curve and geologic analysis for the geological elements of the trap.The application presents that the established evaluation methods and criteria for the geologic risk in a buried hill trap can reflect the geological characteristics and actual exploration situation of the exploration area.
INFLUENTIAL FACTORS IN NATURAL GAS MIGRATION AND ACCUMULATION
Zhu Huayin, Li Jian, Li Yongjun
2006, 28(2): 152-154. doi: 10.11781/sysydz200602152
Abstract:
The factors influencing gas migration are studied by simulating natural gas migration in natural core,using long-core experimental installation.Natural gas migration is related to the physical characteristics of rock and the pressure of gas source.Gas migrates first into large pores of migration formations after overcoming the influence of capillary pressure.If migration formations have good physical properties and much larger pores,much more gas will be accumulated,otherwise it will migrate far away.It does not depend on time because the rate of gas movement is fast.When the pressure of gas resource is large enough to overcome capillary pressure,gas can migrate forward transiently.The differences between migrating upwards and downwards are great because of the buoyancy force.It is easy and high efficient to migrate upwards. The distance of gas migration upwards is three times of that of downwards in the same conditions.
ANALYSIS OF CARBON AND OXYGEN ISOTOPE ON THE ORDOVICIAN DOLOSTONES IN THE ORDOS BASIN
Liu Deliang, Sun Xianru, Li Zhensheng, Tang Nanan, Tan Ying, Liu Bo
2006, 28(2): 155-161. doi: 10.11781/sysydz200602155
Abstract:
In order to know the formation surroundings of the Ordovician dolostone that is Lower Paleozoic reservoir of natural gas in the Ordos Basin,the relationship between its genetic type and carbon and oxygen isotope is studied.Carbon and oxygen isotope of penecontemporaneous dolostone is heavy,whose δ13C value varies from 0.639‰ to -2.2‰ and δ18O value does from -0.2‰ to -8.668‰.The penecontemporaneous dolomite rock forms in saline water body.δ13C value of diagenetic dolostone varies from 0.9‰ to -3.2‰ and δ18O does from -1.7‰ to -7.067‰.The diagenetic dolostone froms in high-magnesian saline water body.Carbon and oxygen isotope of immerged dolostone is light,whose δ13C value varies from 0.580‰ to -3.7‰ and δ18O value does from -6.88‰ to -9.97‰.The formation surrounding of immerged dolostone is higher temperature,lower salinity and lower-magnesium.δ13C value of carbonate vein in dolostone most is from -1.00‰ to -5.66‰,while that in limestone most is from -1.30‰ to -8.65‰.Oxygen isotope of carbonate vein is lighter with narrow ranges,whose value varies from -10.66‰ to -18.91‰,and its Z value most is 100 and 110.Those indicate there was fresh-water leaching during formation of carbonate vein.
GEOCHEMICAL CHARACTERISTICS OF MAIN SOURCE ROCKS IN THE NANPANJIANG BASIN
Zhao Mengjun, Zhao Ling, Zhang Shuichang, Liu Peichu
2006, 28(2): 162-167. doi: 10.11781/sysydz200602162
Abstract:
Based on the study of depositional environment,black argiloid of the Middle and Lower Devonian is the most important source rock,and the source rocks of Carboniferous,Permian and Middle and Lower Triassic are accessory in the Nanpanjiang Basin.120 samples from 6 shallow wells indicate that,source rocks of the Middle and Lower Devonian have a total carbon content varying from 0.37% to 3.63% with an average of 1.65%.They are sapropelic and over-mature in thermal evolution.Biomar-kers of source rock reflect the marine source features of Paleozoic with higher content of lower carbon number compounds such as pregnanes and tricyclic terpanes in almost all samples because of the very high source maturation.
GEOCHEMICAL CHARACTERISTICS OF OIL IN THE QOM BASIN OF IRAN
Xu Li, Wang Yongjun, Li Zheng
2006, 28(2): 168-172. doi: 10.11781/sysydz200602168
Abstract:
It is maturated oil that two kinds of crude oil have been discovered in the Qom Basin of Iran.The abundance of isoprenoidies is relatively low,and no preference between pristane and phytane of crude oil in the Kashan block.There are relatively high abundance of Ts,C30-diahopane and low abundance of gammacerane in trepans.There is relatively high concentration of diacholestane in steranes.The abundance of isoprenoidies is relatively high, and there is preference phytane of crude oil in the Alborz oilfield.There are relatively low abundance of Ts,C30-diahopane and high abundance of gammacerane in trepans.There is relatively low concentration of diacholestane in steranes.These geochemical characteristics of crude oils show that they generated from different of sediment.It indicates that there are good conditions of source rock.
EFFECTS OF ELEMENT SULFUR ON CARBON ISOTOPIC FRACTIONATION OF METHANE
Lei Tianzhu, Zhang Gengxin, Qiu Junli, Xia Yanqing, Nan Qingyun
2006, 28(2): 173-176. doi: 10.11781/sysydz200602173
Abstract:
The effects of element sulfur on carbon isotopic fractionation of methane have been systematically studied by the simulation experiments of thermal transformated methane from organic matter.The results show that during the low to middle temperature,the values of methane carbon isotope from similitude kerogen and total rock are lighter in the presence of element sulfur than in the absence of element sulfur.The changing extent of carbon isotope is different at different tempertures and the organic type by effects of element sulfur.Carbon isotopic value of methane from similitude kerogen is lighter than that from total rock in the presence of element sulfur.Carbon isotopic values of methane from total rock series are lightening with the increasing maturity of organic matter in the presence of element sulfur.Mechanics analysis revealed that element sulfur is mostly effect carbon isotopic values of methane as a reactant.
CHARACTERISTICS OF SOURCE ROCK OF THE KONGDIAN FORMATION IN SOUTH SLOPE OF THE DONGYING SAG, THE BOHAIWAN BASIN
Yuan Caiping, Xu Sihuang, Jia Huofu, Wang Xinzheng, Han Zhongyi
2006, 28(2): 177-181. doi: 10.11781/sysydz200602177
Abstract:
The source rocks of lower Es3 and upper Es4 are high quality source rock in the Dongying Sag of the Bohaiwan Basin.It was considered that the crude oil on south slope of the Dongying Sag mainly came from Es4 source rock;while it was argued that whether Ek2 can generate hydrocarbon.The correlation between oil and source rock shows that Ek2 source rock differs from Es3 source rock with higher gammacerane and differs from Es4 source rock with higher trishomohopane and S configuration of C29 sterane.There is consanguinity between crude oil in deeper layers and Ek2 source rock.Although Ek2 source rock was found belongs to bad source rock with lower organic carbon,poorer type of kerogen and higher maturity,it optimizes toward the sag center based on biomarkers.So it is presumed that there would be good source rock of Ek2 in its sedimentary center,and the genetic potential of Ek2 would be large.
ANALYSIS OF SURFACE GEOCHEMICAL CHARACTERISTICSOVER TYPICAL GAS POOL——TAKE XIAOQUAN-XINCHANG GAS FIELD IN THE SICHUAN BASIN AS AN EXAMPLE
Ren Chun, Xia Xianghua
2006, 28(2): 182-186. doi: 10.11781/sysydz200602182
Abstract:
By analyzing relations between surface geochemical indicators and deep gas pool in Xiaoquan-Xinchang gas field of the Sichuan Basin,one can obviously obtain that large numbers of surface geochemical tracks from deep gas accumulations is closely response to the types and scales of deep gas accumulations.Using geochemical detecting methods,one can catch these micro-traces,thus providing deep gas accumulations exploration with reliable basis.The anomaly shape of acid hydrocarbon,ΔC,heat-released hydrocarbon and micro magnetism is mainly annular or spotted.Head-space gas is a good indicator to deep gas accumulations.It is characterized by concentration changing greatly over gas accumulation and changing little out of gas accumulation.Microbiological indicator is corresponding to deep gas accumulation.Methane oxidation bacteria have annular or spotted anomaly features.Sulfate-reducing bacteria show a character of top anomaly.For reducing risk of prediction and increasing rate of success in gas exploration,it is needed to combine surface geochemical indicators with geologic setting.
RELATIONSHIPS BETWEEN FORMATION WATER VERTICAL ZONING AND OIL AND GAS ENRICHMENT IN LANGGU SAG OF THE BOHAIWAN BASIN
Zhang Xiaoli, Zha Ming, He Shuanzhu, Wang peng
2006, 28(2): 187-190. doi: 10.11781/sysydz200602187
Abstract:
Formation water vertical characteristics are complex in Langgu sag,Jizhong depression.The vertical distributions of the formation water chemic and dynamical belts have obvious zoning features.According to the vertical characteristics of the formation water chemic and dynamical belts and the relations with fluid compartment and distribution of oil and gas in Gu'an-Jiuzhou,Liuquan-Caojiawu and Hexiwu tectonic belts,it is considered that formation water can be divided into four belts vertically.They are formation water alternate fluency belt,formation water alternate blocking belt,formation water alternate tardy belt and formation water frequency alternation belt.It is also considered that formation water alternate blocking belt tallies with fluid compartments and is the beginning segments of oil and gas enrichment.Meanwhile,formation water alernate tardy belt basically locates under the fluid compartment and it is the favorable area of oil and gas enrichment.Furthermore,the area with relatively high value of salinity in the lower salinity beckground is available to oil and gas enrichment.
EXPERIMENTAL STUDY ON ULTRASONIC EFFECT IN OIL RESERVIOR
Wang Ruifei, Sun Wei, You Xiaojian, Zhang Rongjun, Cheng Hua
2006, 28(2): 191-195. doi: 10.11781/sysydz200602191
Abstract:
By means of the principle that ultrasonic reaction can change the flowing of fluids through porous media and fluid rheological behavoirs,the changes of the curves of core permeability and pressure gradient before and after ultrasonic reaction have been researched.The efficient distance of ultrasonics in the oil layer was discussed in the paper.The study results show that the apparent viscosity of crude oil after ultrasonic reaction decreased greatly,and that the sound rheological behavior of the oil is obvious.The bigger the ultrasonic reaction power is,the stronger the effect on viscosity reduction of crude oil is.The lower the ultrasonic frequency is,the greater the extent of viscosity reduction of crude oil is.The higher the oil viscosity is,the greater the extent of viscosity reduction of crude oil is.
IMPROVEMENTS FOR CLAY SEPARATION FROM CLASTIC SAMPLES
Feng Xue, Wu Chaodong, Xi Xianting
2006, 28(2): 196-200. doi: 10.11781/sysydz200602196
Abstract:
Sample preparation is the basic stage in clay experiment.The traditional method is limited to those loose-structured samples,thus unfit for samples with diagenesis.A synchronous picking-up method is used in sample preparation and analysis of 42 pieces of Mesozoic mudstone and sandstone from the Kuche Sag of the Tarim Basin.Samples are separated into 4 sections: 20 μm,20-5 μm,5-2 μm and 2 μm with parameters calculated.The results are well proved by laser analysis.