石油实验地质

THE SHIFT OF CENOZOIC VOLCANOES AND THE SPREADING AND DRIFTING OF CONTINENTAL RIFTS IN THE EASTERN CHINA

Deng Jinfu, Zhao Hailing, Ye Delong, Lu Fengxiang, Mo Xuanxue

1993, 15(1): 1-10. doi: 10.11781/sysydz199301001

Abstract(665) PDF-CN(604)

Abstract:
Cenozoic basaltic volcanism of the eastern China continental rift system is mainly concentrated in three NE-extending narrow rift belts. From northwest to southeast, they are the Daxinganling-Taihangshan Belt, the Changbaishan-Tanlu Fault Belt and the Southeast Coast belt. In each of these belts, Quaternary basaltic volcanoes are located a-long the axial area of rift belts, whereas Tertiary basalts are distributed on each of the flanks of these belts. Similar to the distribution of basalts on mid-ocean ridge and its flanks, the earlier Tertiary basaltic volcanoes shifted outward from the axes of the rifts as a result of continental rift spreading. In addition, the axis of the Quaternary basaltic volcanoes is located in the northwest side of the Tertiary basaltic volcanoes, suggesting the continental lithosphere of the eastern China drifted southeastwards. The spreading and drifting rate of the continental rifts can be estimated respectively from the shifting distances and time interval of volcanoes. The direction of tectonic stress, which is deduced from the echelon arrangement of three NE-extending volcanic belts, suggests that the formation and spreading of the eastern China continental rift system is genetically related both to the northward movement of the India Plate and the northwestward movement of the Pacific Ocean Plate.

RESERVOIR SYSTEM——AN IMPORTANT RESERVOIR PATTERN FOR GAS ACCUMULATION IN TIGHT CLASTIC ROCKS

Yin Fengling, Liu Jichang, Li Guixue, Guo Dongxiao

1993, 15(1): 11-19. doi: 10.11781/sysydz199301011

Abstract(563) PDF-CN(289)

Abstract:
In this paper, a reservoir system is proposed based on the characteristics of the tight clastic rocks in the western Sichuan Basin. Such a reservoir system is defined as a geological body with effective pores and permeable channels of three-dimentional space,but without limitation on lithology and formational boundary. It is an important reservoir pattern for gas accumulation in tight clastic rocks. With combination of the geological settings of the west Sichuan Depression, the authors discuss the identification and the formative conditions of the reservoir systems in the paper.

SIMULATIONS ON THE FORMATION AND EVOLUTION OF CONTEMPORANEOUS FAULTS IN THE LOWER YANGTZE AREA

Shi Zejin, Huang Zhongjin, Chen Wei

1993, 15(1): 20-28. doi: 10.11781/sysydz199301020

Abstract(547) PDF-CN(372)

Abstract:
In this paper,nonlinear theory and plastic flowing theory are applied to the study of contemporaneous faults, and the analysis program for the simulation of the formation and evolution of the contemporaneous faults have been written by using FORTRAN 77 Language with two-dimention elastic-plastic nonlinear (equal-parameter, eight-node elements). The study suggests that the growth of contemporaneous faults originated from the stress of the hanging walls. Combining with the geological and geophysical data of the study area, it is also proposed that the formation of the Tai Lake Dome Structure was brought about by the upward-stress due to the soft layers' thickenings resulted from plastic flowing at the bottom of sedimentary cover under the action of horizontal stress-field. In addition, it is suggested that the formation of grabens and horsts would be related to the faults developed in early stage and their boundary conditions, and is the result of their assembled efffects.

AN APPLICATION OF TTI IN RECONSTRUCTION OF ORIGINAL THICKNESS OF SEDIMENTARY SEQUENCES-A CASE STUDY OF THE WEST SHANXI AND NORTH HENAN AREAS

Chou Fukang

1993, 15(1): 29-36. doi: 10.11781/sysydz199301029

Abstract(527) PDF-CN(243)

Abstract:
The maturity of organic matter in sedimentary rocks is the accumulating effects of thermal evolution in burial history. Such an accumulated effect could be expressed by time-temperature-index (TTI) or vitrinite reflectance (R°), The greatest burial depth and the original thickness of sedimentary sequences can be obtained by the method of reversion, once the TTI (or R°) and the burial history in certain areas are available. The precision of this method depends on the parameters, such as geothermics and thickness of sedimentary sequences, TTI,R°,etc.. If upliftings and sudsidings take place,you should make corrections both on the depth and the thermal effects of time-temperature.

AN APPROACH TO THE ORIGIN TYPES OF NATURAL GAS IN THE NORTHERN TARIM BASIN

Yang Dujing

1993, 15(1): 37-48. doi: 10.11781/sysydz199301037

Abstract(504) PDF-CN(260)

Abstract:
Based on plenty of systematic analytical and experimental data and geochemical characteristics of petroleum exploration in the northwest Tarim Basin, the paper mainly approaches the compositions, light hydrocarbons, and carbon isotopic characteristics of the natural gas, as well as the divisions of the origin types in the area. The study reveals that the northern Tarim Basin is dominated by oil-prone gas with minor coal-prone gas and mixed gas. However,the Yakela uptaulted area is mainly predominated by gas-conden-sate gas, while in the Akekule embossed area, it prevails pyrolytic gas. Only minor helium gas is produced at the Shaxi uplifting area.

ON THE SANDSTONE COMPACTION OF JURA-TRIAS SYSTEMS AND THE PETROLEUM GEOLOGICAL SIGNIFICANCE IN THE NORTHEAST TARIM BASIN

Wang Xu, Liu Shuhui, Ye Desheng, Zheng Weilin

1993, 15(1): 49-59. doi: 10.11781/sysydz199301049

Abstract(555) PDF-CN(329)

Abstract:
The sandstone compaction of Jura-Trias systems is both widespread and severe in the Northeast Tarim Basin, of which the mechanical compaction predominates the chemical one. The mechanical compaction is generally strengthened along with increasing of burial depth, but not always transformed into chemical compaction. However, the sandstone compaction is mainly dominated by rock property, sedimentary environment and burial history. In accordance with compaction strength, the sandstone compactions in the study area can be divided into three grades of Ⅰ, Ⅱ and Ⅲ respectively. The more severe compaction, the more favourable for oil/gas generation, but unfavourable for the formation and the preservation of pores. Therefore, the weak compaction is favourable for the development of good reservoirs, but disadvantageous to the transformation of organic matter.

GEOLOGICAL AND GEOPHYSICAL INTERPRETATIONS FOR THE FORELAND OF THE LONGMENSHAN, WESTERN SICHUAN

Xu Xuhui

1993, 15(1): 60-73. doi: 10.11781/sysydz199301060

Abstract(552) PDF-CN(340)

Abstract:
On the basis of the data derived from surface geologic observation and geophysics, the author considers that the Longmenshan Area and its foreland are characterized by the alignment of east-west zones and south-north blocks. Consequently, five fault models are established respectively for listric faults,terrace-faults, undulate faults, dome-faults and strike-slip faults,as well as two folding structural models related to faultings and fault assemblages. Thereafter, it is proposed that the area underwent piggyback shiftings from east to west during the time of the Indosinian-Xishanian and four detachments have been brought about along the four tectonic levels at the bottom of the Upper Sinian, Silurian, Lower and Upper Triassic systems respectively. It is believed that the excellent structural traps closely related to thrusts would develop in the Palaeozoic and Mesozoic systems, at the deeper depth of the Longmenshan Foreland.

A STUDY ON MUDSTONE COMPACTION AND OIL/GAS MIGRATION BY SEISMIC DATA IN THE BEISANTAI AREA

Liu Funing

1993, 15(1): 74-80. doi: 10.11781/sysydz199301074

Abstract(579) PDF-CN(253)

Abstract:
The author of this paper studied the effects of lithology and the property of pore fluids on seismic velocity through the analysis of the data of acoustic loggings, vertical seismic sections and stacking velocity. It is suggested that the analysis can be carried out on the mudstone compaction and oil/gas migration by using seismic data and information. Based on the calculations of the formational fluid pressure by the data of seismic velocity with equivalent depth method, the hydrodynamics can be analysed. Finally, the orientation of oil/gas migration and possible oil/gas accumulation belts could be inferred with combination of the geological background in a certain area.

THE ORIGIN OF CALCAREOUS CORES IN THE ALLUVIAL SYSTEM OF THE CANGFANGGOU GROUP

Lou Zhanghua, Zhao Xiafei

1993, 15(1): 81-85. doi: 10.11781/sysydz199301081

Abstract(579) PDF-CN(350)

Abstract:
Calcareous cores are widespread in alluvial systems, and the origin of the cores is related to sedimentary environments, deposition rates, climates and drainage systems. The paleogeographic features of alluvial systems can be recognized by analysing the types and origins of calcareous cores.

FEATURES OF THE JIYANG MOVEMENT AND ITS EFFECTS ON THE EVOLUTION OF THE JIYANG DEPRESSION

Chen Jiashu

1993, 15(1): 86-99. doi: 10.11781/sysydz199301086

Abstract(686) PDF-CN(450)

Abstract:
Three important characteristics of the Jiyang movement at the end of No. 4 Sha section of the Jiyang Depression are as follows:both regional tectonic movement and the ups and downs of block faulting as well as the episodic tiltings of faulted blocks. The origin of the Jiyang movement is closely related to the transformation of the Tanlu Fault Belt from sinistral to dextral movements. Therefore, it is a significant tectonism for the development of the Jiyang Depression, and could play an important role on the generation,migration and accumulation of oil/gas in the depression and also provide regional settings for oil formation.

A CORRELATION BETWEEN THE COALS OF DIFFERENT COAL-RANKS AND THE PYROLYTIC PRODUCTS FROM THE COAL-ASPHALTENES

Cai Yunkai, Zhang Aiyun

1993, 15(1): 100-107. doi: 10.11781/sysydz199301100

Abstract(529) PDF-CN(299)

Abstract:
The authors correlated the compositions of pyrolytic products between the coal-as-phaltenes and the coals of different coal-ranks (R_max°0.43-1.80%), by means of PY-GC. The study shows that the pyrolytic products of the coals are generally similar to those of the coal-asphaltenes. Furthermore, in view of the changeable features of n-alkanes observed from different carbon number intervals at the different stages of thermal evolution, it may be clear that coal asphaltenes had contributed to various extents at the different stages of their evolution.

THE MIOCENE SPOROPOLLEN ASSEMBLAGES OF THE EASTERN ZHOUKOU DEPRESSION AND THEIR GEOLOGICAL SIGNIFICANCE

Wu Jianzhuang, Yuan Shu

1993, 15(1): 108-114. doi: 10.11781/sysydz199301108

Abstract(485) PDF-CN(270)

Abstract:
It is the first time to report that the sporopollen assemblages of the Guantao Formation have been discovered in the log section of the Eastern Zhoukou Depression. The assemblages can be divided into two groups. The lower group is in age of early Miocene depending on the correlation to the adjacent areas while the characteristics of the upper group are similar to those of the Shanwang Formation in Shandong provinc and the Taidao type (mid-Miocene) in Japan, and more similar to those of the late Neigene sporopollen assemblage (in age of mid-late Miocene) in the North Jiangsu-South Yellow Sea areas. It is proposed that the assemblage in age of early stage belongs to north subtropical type while that in age of mid-late stages are transformed from warm to cool zones based on the characteristics of their vertical distributions.

1993 Vol. 15, No. 1

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