2001 Vol. 7, No. 1

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BASIC FEATURES AND FORMATION MECHANISM OF PARANEOCATHAYSIAN EXTENSIONAL BASINS SYSTEM
QIU Yuan-xi
2001, 7(1): 1-8.
Abstract (136) PDF (309KB)(6)
Abstract:
There develop a series of dextral transtesoinal fault basins (graben and half-graben) trending NNE since the late Mesozoic (Cretaceous period) in the continental margin of East China and West Pacific Ocean. These basins were arranged as zigzag pattern in the plane view. Under these fault-basins develop upper mantle-uplifting and basement detachments of the same trend. Some times expressed as metamorphic core complex and big low angle extensional detachments. The regional tectonic stress field has been in horizontal extension of NW-SE direction during post-orogenic period since the late Yanshannian stage. It is continental margin expanding caused by the de-rooting of lithosphere (since the late Cretaceous) and the effect of the collision between India and Eurasia plates (since the end of Late Cretaceous and Early Tertiary period).
STRUCTURAL FEATURES, STRESS FIELDS AND STRAIN FIELDS IN FENGHUANGSHAN SILVER MINE AREA, GUANGXI, CHINA
HUANG Ji-jun
2001, 7(1): 9-21.
Abstract (202) PDF (361KB)(27)
Abstract:
Fenghuangshan silver deposit is located in a fault zone which occures along the nortern limb of Xiomingshan fold belonging to Damingshan anticlinoyinm. In the mine area, faults are dominant structures in comparsion with folds and there are three group of faults, WNW-ESE or EW, NE-SW and SN-oriented, among which the first group are the most important and the third group are rare. Joints numerously occurred and can be divided into six groups according to their trends. The area underwent complicated deformation events, which are:(1) NS-oriented compressions in Caledonian and Hercynian(perhaps Indo-China) movement; (2) NW-SE-oriented compression in Yanshan (perhaps Indo-China) movement and;(3) nearly EW and NE-SN oriented compression in Himalaya movement.
GENERAL FEATURES OF THE WESTERN GUANGDONG NAPPE TECTONIC SYSTEM AND ITS CONTROL ON THE NOBLE METAL AND POLYMETALLIC DEPOSITS
ZHU Da-gang, MENG Xian-gang, PENG Shao-mei, FENG Xiang-yang, SHAO Zhao-gang, WANG Jian-ping
2001, 7(1): 22-32.
Abstract (151) PDF (428KB)(7)
Abstract:
The western Guangdong nappe tectonic system was formed in the Hercynian and Indosinian epech. Its tectonic styles belong to the folding and thrusting nappe structure, the extended way is piggyback propagaton. The allochthon consists of the Presinian, Sinian and Cambrian Systems. The autochthon comprises the Devonian and Carboniferous Systems. The most of the subsidiary thrusting fracture shows the plough-shaped with the upper steep and the lower flat form. The structure assemblage of the nappe tectonic system is perfect in the cross section, and the structure belts andthe tectonic units show the mineralization and controling ore deposits, which can be divided into the five-types according to the occurrence condition:①the ore in the flat of gliding nappe belts-the Xinrong manganese ore, silver and gold mineralization;②the ore in the ductile shear zones of the basement detachment nappe doming-the Hetai gold deposit;③the ore in the ductile shear zones of the ramp rise-the Dagougu gold deposit;④the ore in the nappe folding and thrusiting belts-Dajiangping pyrite deposit; ⑤the ore in the folding and thrusiting belts in the basin-Shijing gold deposit; ⑥the ore in the front stripping extension fault belts-Changkeng gold and silver deposit. The correlation and harmony of the different typical deposits suggest the mineralization and controling ore deposits are governed mainly by the nappe tectonic system besides the strata and lithology.
TECTONIC DEFORMATION OF YAKERLA-LUNTAI REGION IN NORTH TARIM BASIN AND ITS CONTROL ON OIL/GAS ACCUMULATION
ZHOU Xin-gui, SUN Bao-shan, XU Hong-jie, DUAN Tie-jun, SHE Xiao-yu
2001, 7(1): 33-40.
Abstract (125) PDF (308KB)(7)
Abstract:
In the present paper, the tectonic deformations of the Yakela-Luntai region of North Tarim basin and their evolution have been detailedly described. It is considered that the most important factors controlling oil/gas accumulation comprise long sustained uplifting, repeated faulting, presence of unconformities,favourable structural style etc. A combination of palaeouplifts,large faults and stratigraphic unconformities seems necessary for the formation of economic oil pools. Also the structural trap of oil in the region are discussed at great length and some target spots for subsequent exploration are proposed.
THE EFFECT OF EFFECTIVE PRESSURE ON POROSITY AND PERMIEABILITY OF LOW PERMEABILITY POROUS MEDIA
LIU Jian-jun, LIU Xian-gui
2001, 7(1): 41-44.
Abstract (208) PDF (129KB)(9)
Abstract:
On the basis of experimental study,the law of porosity and permeability versus effective pressure are developed, Because porosity of low permeability media is very small, a little change of its porosity can make its permeability decline rapidly. The paper is useful in solid-fluid coupled simulation of oil reservoir. The paper gives coupled relations in solid-fluid coupled simulation. During the oil and gas field developing,the coupled effect should be considered.
AN ANALYSIS ON THE PRINCIPAL CONTROL FACTOR OF COAL RESERVOIR PERMEABILITY iN CENTRAL AND SOUTHERN QINSHUI BASIN,SHANXI
FU Xue-hai, QIN Yong, LI Gui-zhong, LI Tian-zhong, HU Chao
2001, 7(1): 45-52.
Abstract (121) PDF (259KB)(10)
Abstract:
According to measurement and statistics of down coal mine macrofractures were classified into four ranks,and systemically described and measured under scan electron microscope. Based on the analysis of relationship between permeability and ground stress/buried depth, fractures, reservoir pressure, hydrogeological condition, authors point out that ground stress/buried depth is principal-control factor. Under the same buried depth other factors play more important role on permeability.
STRENGTH CRITERION AND INTERNAL FRICTION COEFFICIENT OF ROCK SPECIMEN
YOU Ming-qing, HUA An-zeng
2001, 7(1): 53-60.
Abstract (207) PDF (273KB)(14)
Abstract:
Rock is heterogeneous material with various flaws. The ideal strength of rock specimen can be determined from its complete stress-strain curve. After specimen is failed the experiment, reducing confining pressure and keeping the constant axial deformation, was carried out. According to the experiment the relationship of loading capacity of specimen, which is sustained by the internal friction, with confning pressure is given. To compare the relations of residual strength and peak strength with confining pressure,the internal friction coefficient in the yielding process is studied. The effect of internal friction coefficient on deformation and strength of various rock specimens is discussed. For siltsand, the internal friction coefficient reaches the maximum at the peak strength, and then the cohesion or material strength decreases only, so the confining pressure does not influence the specimen's deformation beyond the peak stress.For marble, the internal friction coefficient increases in the whole yielding, and the increasing of internal friction is various with the normal stress on the shear surface or confining pressure. At high confining pressure, the maxitmum axial stress is realized by internal friction when material strength of the specimen has wholly lost. The increasing of internal friction coefficient results in the transformation of brittle to ductile.
THE MEASUREMENT AND STUDY ON IN SITU STRESS IN THE CENTRAL AREA OF THE HUANGCOU ACCUMULATION POWER STATION, HEILONGJIANG
WU Man-lu, LIAO Chun-ting
2001, 7(1): 61-68.
Abstract (153) PDF (251KB)(8)
Abstract:
Based on the results from in situ stress measurement in Huanggou Accumulation Power Station,Heilongjiang, the authors analyse the characteristics of the in situstress. The calculation of measurements from four sites in underground plant by method of least squares shows that the maximum principal stress is nearly horizontal with N78°W trending of 9.6MPa. The result is consistent with the present tegional stress field manifested by investigation of neotectonics, and also with the regional stress field in northeastern China.
APPLICATION STUDY OF THREE DIMENSIONAL GEO-STRESS MEASUREMENTS BY USE OF HYDRAULIC FRACTURING METHOD
CHEN Qun-ce, LI Fang-quan, MAO Ji-zhen
2001, 7(1): 69-78.
Abstract (122) PDF (310KB)(20)
Abstract:
The theoretical model created based on minimum principal stress criteion is a new thinking of the three dimensional geo-stress measurements made by hydraulic fracturing method. According to the theoretical study and in consideration of real situation of test, this paper emphasizes on the influence of observed dsts error on test results in detail,and confirm the reliability and applicability of this method resalting from the theoretical model for three-dimensional geo-stress measurements.
THE EVOLUTION OF MESOZOIC-CENOZOIC BASIN-MOUNTAIN STRUCTURE IN THE EAST YANSHAN AREA AND XIALIAOHE BASIN
MA Yin-sheng
2001, 7(1): 79-91.
Abstract (153) PDF (458KB)(10)
Abstract:
The author discussed the pre-Mesozoic structure background and the Mesozoic-Cenozoic basinmountain structure evolution in the east Yanshan area and Xialiaohe Basin. The author considers that the Mesozoic-Cenozoic structure evolution process in the east Yanshan and Xialiaohe Basin is a alternate process of intracratonic (intracontinental or intraplate) basin-mountain structrue and compression structure in the basement of pre-Mesozoic North China Craton lithosphere. It experienced five periods of basin-moun-tnin evolution(Early and Middle Triassic, Late Triassic to Early Jurassic, Middle and Later Jurassic,Cretaceous and Cenozoic) and five compression deformation stages (the end of Middle Triassic, Early Jurassic, Late Jurassic, Cretaceous and Paleogene). The compression not only resulted in withering or disappearing of the early basins, but also made them deform or be responsible for the basin reversion. The extensions in Middle and Late Jurassic, Cretaceous and Cenozoic resulted in Middle and Later Jurassic fault basin, Cretaceous fault basin and Cenozoic rift basin. The compression and extension appear alternatively, associated Compression structures and extensional structures developed alternatively in the process.
RESEARCH ON MARBLE KAISER EFFECT AFFECTED BY TIME FACTOR
FAN Yun-xiao
2001, 7(1): 92-96.
Abstract (158) PDF (195KB)(7)
Abstract:
Marble specimens were reloaded after two months to investigate that time factor has influence on Kaiser effect. The results show that after two months the marble has poor ability to remember its previous stress and strain, but can remember its previous damage very accurately. Therefore from the view of time factor the mechanism of Kaiser effect of marble is reflect of rememberance of rock previous damage.