2000 Vol. 6, No. 2

Display Method:
AN ESTIMATE OF THE RATE OF UNDERGROUND FLUID FLOW FROM WELL-TEMPERATURE DATA IN YING-QIONG BASIN
ZHANG Jian, GE She-min, XU He-hua, XIONG Liang-ping, YANG Ji-hai, ZHANG Qi-ming
2000, 6(2): 1-5.
Abstract (152) PDF (205KB)(8)
Abstract:
The Ying-Qiong basin is a typical high temperature and high pressure basin.The value of heat flow in this basin averages as high as 78.7mW/m2 which is revealed to be caused by active thermal fluid at depth.Based on the relationship between the geothermal field and the activity of underground fluid,we have calculated the distribution of the fluid flow rate from the temperature data of well LD30-1-1A.The results show that the vertical fluid flow rate is as slow as 8.33×10-12 cm/s in the upper part of the well 4.37×10-8 cm/s downward in middle part,and 2.65×10-8 cm/s upward in the lower part.
THE FULLY COUPLED FLUID-SOLID ANALYSIS FOR THE RESERVOIR ROCK DEFORMATIONS DUE TO OIL WITHDRAWAL
DONG Ping-chuan, LANG Zhao-xin, XU Xiao-he
2000, 6(2): 6-10.
Abstract (159) PDF (193KB)(6)
Abstract:
The effective normal stress in a hydrocarbon reservoir will increase as a result of the decline in pore fluid pressure associated with the withdrawal of fluids,thus leading to a compaction or deformation of the reservoir rocks,with a consequent decrease in permeability and production,and a failure of the oil wells and the casings,and sometimes subsidence of the ground surface.The reservoir rock deformation due to fluid tapping can be described by a general 3-D deformation field coupled with a 3-D fluid flow field.A finite element numerical model for a fluid flow in a deforming porous medium is here presented to simulate the response of an oil reservoir subject to fluid withdrawal wherein axisymmetric flow and deformation occur simultaneously.A few useful conclusions are obtained and can be used to explain the practical problems encountered during oil production.
CHARACTERISTICS OF NONMARINE COMPLEX PETROLEUM SYSTEM IN CHINA
QU Hui, ZHAO Wen-zhi, ZHANG Ming-li
2000, 6(2): 11-16.
Abstract (92) PDF (207KB)(19)
Abstract:
The study of petroleum system forms one the hot subjects in petroleum geology,and plays an important role in oil/gas exploration.The petroleum systems in nonmarine multi-cycle composite basins in China shows much complexity with multiple sources,multiple kitchens,multistage hydrocarbon generation and pooling.Such complex petroleum system has three obvious features:① superimposition and interlacing one after another of the system as a result of multiple sources and multiple kitchens;②mixed oil generation arising from multistage hydrocarbon generation and pooling;③multiple critical time.Repeated large-scale oil/gas migration would usually have occurred in the process of evolution of the complex petroleum system,so it is necessary to take into consideration their restoration.Finally,the paper discusses the characteristics of the complex petroleum system in particular,citing the Mahu-penyijingxi complex petroleum system of junggar basin as an example.
DIABASE AND HYDROCARBON RESERVOIR FORMATION ON THE NORTHERN SLOPE OF GAOYOU SAG
LI Ya-hui
2000, 6(2): 17-22.
Abstract (207) PDF (216KB)(10)
Abstract:
Diabase is widespread on the northern slope of the Gaoyou sag.The intrusion of diabase into the oil-and-gas-bearing basin may change the environment of oil and gas formation.This article discusses the relationship between diabase invasion and oil generation,migration and accumulation.It is suggested that diabase invasion may be favourable for the generation,migration and trapping of oil and gas.The mechanism for the formation of the complex fault block reservior is also discussed.
FORMATION OF TAISHAN MOUNTAIN AND CENOZOIC TECTONICISM
ZHANG Ming-li, JIN Zhi-jun, LU Peng-ju, LIU Guo-lin
2000, 6(2): 23-29.
Abstract (186) PDF (292KB)(9)
Abstract:
This paper analyses the Cenozoic tectonism in the Taishan Mountain and the resulting topographic features.It was charactorized by a tilting and uplifting of the northern wall block of the fault front Taishan Mountain during the Cenozoic.Taishan Mountain is a young fault block mountain,being of an age of about 30 Ma.
BASIN EVOLUTIONARY DIFFERENCES AND SEISMOTECTONICS OF FENWEI GRABEN SYSTEM
ZHANG Shi-min
2000, 6(2): 30-37.
Abstract (157) PDF (289KB)(22)
Abstract:
Based on their size,total displacement and tectonic style,basins of the Fenwei graben system(northeast of China) can be divided into four types,the infant(or initial),the young(or growing),the mature and the joining ones,each succeeding stage being developed from the preceding one.
From the infant basin through the young or the mature,there was a decline in the structure barrier(or the resistance of the basin to further depression or expansion) resulting in a decrease of the upper limit of earthquake magnitude.
THE MAGNETIC FABRIC CHARACTERISTICS OF ROCKS FROM ZHONGJIA TIN DEPOSIT AND THE VICINITY,FUJIAN PROVINCE
CHEN Bai-lin, ZHANG Da, WU Gan-guo, CHEN Jin-shui, FANG Li-ming, PENG Run-min
2000, 6(2): 38-44.
Abstract (145) PDF (263KB)(6)
Abstract:
The magnetic fabric of rocks is a reflection of the susceptibility anistropy of the rocks concerned.Magnetic fabric analysis is used in determining the structural features,and the direction of the stresses that produced such features. Study of magnetic fabric features of the Zhongjia tin deposit,Fujian,shows a very small susceptibility anisotropy(P) of the rocks indicating an overall weak deformation.However the relatively well-developed magnetic schististosity with poorly developed magnetic lineation in the quartzose sandstone suggests a NW-SE compression resulting in a flattening in this direction.The marked NW-SE magnetic lineation developed in the volcanic rocks may indicated their flow direction that agrees with the compression.The susceptibility anisotropy of hydrothermally altered rocks is generally lower than that of metamorphozed quartzose sandstone as a result of part reduction of their susceptibility anisotropy.So evidently,the application of magnetic fabric analysis to weakly deformed rocks may be helpful just as in Zhongjia.It is also of significance to the estimation of the rock strain and of hydrothermal homogenization of the preexisting magnetic anisotropy and to the determination of the flow direction of volcanic rock-flow,eventually to the search for the paleovolcanic crater.
DISCUSSION ON PALEOSTRESS MEASUREMENT BY AE METHOD
DING Yuan-chen
2000, 6(2): 45-52.
Abstract (127) PDF (259KB)(6)
Abstract:
Some 14 problems relating to the application of AE paleostress measurement to geological studies are discussed in this paper,in which the creativness,the feasibility,limitations,the applicability and the continued development of the method are emphasized.
ERROR PROCESSING AND PRECISION ESTIMATION FOR ROCK STRESS MEASUREMENT
YONG Xiao-cong, WANG Lian-jie
2000, 6(2): 53-63.
Abstract (188) PDF (344KB)(12)
Abstract:
The least square method for rock stress measurement is described in this paper. The method of precision estimation is improved. Precision estimation is made more reliable using error calculation by the law of covariance propagation. By coordinate transformation of stress we have the differential relationship between the principal stresses and stress components to facilitate deviation calculation. Precision estimation of principal direction is more objective by using principal stress deflection error proposed in this paper.
CRUSTAL STRESS MEASUREMENT IN NORTHEASTERN QINGZANG PLATEAU BY HYDROFRACTURING
WANG Xue-chao, GUO Qi-liang, ZHANG Hui, LIU Zhen-hong
2000, 6(2): 64-70.
Abstract (207) PDF (277KB)(13)
Abstract:
Measurement of crustal stress by hydrofracturing was first made in northeastern Qingzang plateau.As a result we have a stress state of σHmax > σHmin > σV with the horizontal principal stress trending NE-ENE which agrees with the regional structures.
STRESS MEASUREMENTS AND STUDY OF STABILITY OF THE DAMAO TUNNEL
WU Man-lu, LIAO Chun-ting
2000, 6(2): 71-76.
Abstract (182) PDF (184KB)(10)
Abstract:
The results of stress measurements carried out in the Damao tunnel in Hainan Province indicate that predominantly horizontal maximum compressive stress of no great magnitude trends NWW,which agrees with that of the major compressive faults in the area and focal mechanism solution. The results of a triaxial test of the strength of the granite into which the tunnel is excavated are also given. Finally the safety measures during excavation as well as the stability of tunnel are disscussed.
TEMPORAL-SPATIAL PATTERN OF THE MAHUAGOU GOLD ORE DEPOSIT,WESTERN HUBEI, AND THE SEARCH FOR LIKELY LOCATIONS
WEI Chang-shan, XIONG Cheng-yun, JIN Guang-fu, LI Wen-xiang, XIANG Wen-jin
2000, 6(2): 77-81.
Abstract (130) PDF (209KB)(8)
Abstract:
Mahuagou gold ore deposit is a mesothermal-epithermal one controlled by ductile-brittle shear zone.It is characterized spatially by zoning,equidistant distribution and selfsimilarity of the mineralization across the zone,and temporally by pulsation and succession.A search for the most likely location has been carried out on the Au-9 anomalous geochemical area in the third level(C-level)based on the above metallogenetic regularity.It may serve as a guide for the prediction of gold of the shear zone-type and related types in Mahuagou and other areas.
THE CRUSTAL STRUCTURE AND MODE OF CRUSTAL MOVEMENT IN THE SICHUAN-YUNNAN REGION
LI Guo-he, WANG Si-jin, SHANG Yan-jun, ZHANG Qiang
2000, 6(2): 82-91.
Abstract (121) PDF (347KB)(12)
Abstract:
Based on geophysical features,MT results and velocity structure of the crust and upper mantle in the Sichuan-Yunnan area,the crustal structure and tectonic setting in the deep crust are here presented. It has become clear that the thick crust of the area bordering the Sichuan and Yunnan provinces,appears to reflect the SSE extrusion in the continent-continent collision between the Indian plate and Eurasian plate. Its recent activity is characte-rized by block faulting.