1996 Vol. 18, No. 1

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THE CHARACTERISTICS OF THE UNCONFORMITY ON THE TOP OF PRECARBONIFEROUS AND ITS CONSTRAINTS ON OIL/GAS BEHAVIONR IN TARIM BASIN
Ai Huaguo, Lan Linyin, Zhang Keyin, Wu Yajun
1996, 18(1): 1-12. doi: 10.11781/sysydz199601001
Abstract:
In this paper,the formation mechanism and regional occurrence of the unconformity on the top of Precarboniferous in Tarim Basin were studied,and then,its constraints on the migration and accumulation of oil/gas,and roles in the preservation or destruction of pools were disccused. As the result,fault-flod umconformities,flod unconformities and onlay unconformities are that which significantly controlled oil/gas behaviour. The unconformity onthe top of Precarboniferous,together with the permeable zones immediately adjoining it,could act as conduits for oil/gas migration the scondary reserviors by dissolution and the onlay sandstone over the uncoformity could be the sites of oil/gas accumulation.
VOLCANIC ERUPTION-EFFUSION AND THEIR RELATIONSHIP WITH THE FORMATION AND TYPE OF SEMI-INORGANIC GAS
Xiong Shousheng, Lu Peide
1996, 18(1): 13-35. doi: 10.11781/sysydz199601013
Abstract:
Based on hydrocarbon formation in modern volcanic activities and Simulation experiments of hydrogenation, sedimentary environmewts and hydrocarbon-generation characteristics of source rocks associated with volcanics in faulted basins were studied and summarized,and the concept of semi-inorganic gases was suggested. The enviroment of volcanic spout and effusion is presupposition essential for low mature sowrce rocks to produce hydrocovrbons effectively;and hydrogenation of magmatic hyperthermal gas-liquid upon sedimentary organic matters is thecondition for the generation of semi-inorganic gases. Due to different modes of volcanic Eruption-effusion. different types of semi-inorganic gases were generated.
THE CAPILLARILY SEALING CHARACTERISTICS OF MUDSTONE CAPROCK OF CARBONIFEROUS IN LUNNAN AREA AND ITS CONTROL TO OIL AND GAS ACCUMULATION
Fu Guarg, Chen Zhangming, Jiang Zhenxue
1996, 18(1): 36-41. doi: 10.11781/sysydz199601036
Abstract(1043) PDF-CN(244)
Abstract:
Lunnan area is one of the most significant targets in Tarim in that of oil and gas were abundantly accumulated. The mudstone of Carboniferous,serving as the regional caprock of both carboniferous sandstone reservoir and ordovician limestone fractured reservoir,Owns strong capillarily sealing ability. Morever, the formation period of this capillarily sealing bed well matched for that in which oil and gas were signifccantly generated in the sowrce rock of mid-upper Ordovician in Manjiaer depression. therefore, the mudstonecaprock of carboniferous is favorable to accumulating the oil and gas in Carboniferous and Ordovician to formpools.
LOWER CARBONIFEROUS FORAMINIFERA AND STRATIGRAPHIC CORRELATION IN DRILL, OF THE NORTHERN PART OF TARIM BASIN, XINJIANG
Li Hanmin
1996, 18(1): 42-56. doi: 10.11781/sysydz199601042
Abstract:
The Lower Carboniferous in drills of the northern part of Tarim Basin can be divided into three forastions from top to bottom: Yangbaxi, Kalashayi an Bachu. Abunbant foraminiferal and fusulinid fossils occur in Yangbaxi and Kalashayi formation. Fusulinid fossit amounting up to 4 genera and 18species belongs' to Eostaffella zone. Foraminferal fossil containins up to 25 genera and near 60 species could be categorizedas two assemblages: 2. Endothyranopsis cassus——Archaediscus krestovnikovi; and 1. Endothyra inflataf minima——Archaesphaera minima. The geological age of both fusulinid zone and 2 foraminiferal assemblage is from middle-late Visena to early namuran, and that of 1 foraminiferal assemblage is middle Tournaisian.
PALEOENVIRONMENT AND PLLEOECOLOGY OF DONGYING SAG DURING LATE SHAHEJIE Ⅲ(OLIGOCENE)
Guo Qiulin, Li Peng, Ni Bingrong
1996, 18(1): 57-63. doi: 10.11781/sysydz199601057
Abstract:
The paleoenviroment of Dongying Sag is studied by focusing on the features of Ostracoda fossil community and paleoecology, especially the dominance(dm) and diversity(Hs)of Ostracoda. The five enviroments in the late shahejie Ⅲ(Oligocene) of Dongying Sag are distinguished: 1) floodplain-coastal lake; 2) alluvial delta plain; 3) shallow lake-delta fron; 4)sub-deep lake-prodelda ;5)lake bay.
THE GEOLOGICAL STRUCTURE OF THE XIEFENG MOUNTAINS-YUANMA BASIN AND ITS SIGNIFICANCE TO OIL EXPLORATION
Fan Xiaolin
1996, 18(1): 64-70. doi: 10.11781/sysydz199601064
Abstract:
To study the relationship among mountain system, basin and hydrocarbon is an important (element) in hydrocarbon-bearing basin analysis.The Xiefeng mountain system and the Yuanma basin have been controlled by "intraplate deformation" dynamic condition since the Meso-Cenozoic, and the‘basinmounfain sysfem' wes formed. The orogenic compressional activity controlled basional structural (sedimentary) pattern and petroleum system resulted in ‘structural reversion' of the basin and damage or re-organization of hydrocarbon accumulation. It is very important to study the ‘mountain system-basin-hydrcoarbon' system of the area to evaluate and explore for oil and gas in the continental basins of the South China.
AN EVALUATION OF HYDROCARBON RESORCES OF THE YITONG GRABEN
Li wei, Li Mingcheng, Li Guangdong
1996, 18(1): 71-77. doi: 10.11781/sysydz199601071
Abstract:
More than 100 wells have been drilled in the Yitong graben since 1987. Heowever, there is a considerable difference between the results respectively from previous calculation and exploration. By using the method of the authors, the generation expulsion and accumulation of hydrocarbons were computed in the area. The result showed that the present discovered resources is only 10% of the total accumulation. The main reasons were explained as follows: sediments are badly sorted because of being near sourceland, which resulted in a little difference in properties between reserviors and mudstones, and lack of regional seals or direct caprocks. Due to large space of secondary migration most of hydrocarbors was absorpted or escaped in the horizons and was difficult to form pools.
THE SOURCES OF GAS POOLS IN YINGHUANG FORMATION AND ITS EXPLORATORY IMPLICATION IN THE YINGGEHAI BASIN
He Jiaxiong
1996, 18(1): 78-87. doi: 10.11781/sysydz199601078
Abstract:
The question about the source of shallow gas accumulation with normal pressure in Yinghuang formation is a key to gas exploration and geological research. Based on geological and geochemical data,teh hydrocabon sources and accumulation conditions were analysed in detail. Conclusively,the shollow gas pools with normal pressure mostly sourced the rocks of the middle and lower Yinghuang formation.
LIGHT HYDROCARBON CON STITUENTS OF THE BIODEGRATION GAS AND GAS-SOURCE CORELATION
Zhang Linye, Li Juyuan, Li Xiangchen, Tang Hongsan
1996, 18(1): 88-95. doi: 10.11781/sysydz199601088
Abstract:
This paper gives a discussion on geochemical characteristics of natural gas in the shallow reservoir in Gudao area of Jiyang Depression. The gas suffered serious biodegradation. Original geochemical features are changed because of biodegradation. Correlation of gas-sourece for this gas is difficult. This paper uses technology of heavy hydrocarbon concentration of natural gas to detect biological markers of sterane and terpane, and defines gas-source of biodegradation gas with the aid of data of rare gas isotopes Basis is provided for Clarifying exploratory target.
A STUDY ON THERMAL EVOLUTION OF ORGANIC MATTER IN LOWER TERTIARY SOURCE ROCK OF SUBEI BASIN
Li Xianqing, Bao Jianping, Wang Wenjnn
1996, 18(1): 96-105. doi: 10.11781/sysydz199601096
Abstract:
Based on many optical and chemical indexes the characteristics and stages of thermal evolution of organic matter in lower Tertiary source rock of Subei Basin were studied in this paper. The following four conclions could be made from the stydies: (1)the vitrinite reflectance (Ro)is the most reliable scale for thermal evolution, (2)With the same fluorescence alternation Sporinite and alginite,are of special importance in thermal evolution, (3)the component and struture of soluble organic matter in source rock changed greatly as the degree of thermal evolution increase, (4)the thermal evolution of organic matter in Subei Basin could be divided into two stages,i. e. stage Ⅰ and stage Ⅱ, which by 0.60%~0.65% Ro,and moreover, the difference of maturity in different tectonic units was showed.
EXPERIMENT ON CLASTIC DISSOLUTION OF HEAVY OIL RESERVIORS AND ITS GEOLOGICAL SIGNIFICANCE
Dun Tiejun
1996, 18(1): 106-110. doi: 10.11781/sysydz199601106
Abstract:
In the process of heat mining of heavy oil, sands seriously come out from oil-well as a result of interaetion of clasts of the reserviors with the injected alkaline steam, which remains a technical problem in the world. 10 core samples from the most severe sand well of Biqian G51310 of Henan oil field were experimented on elastic dissolution under site heat mining conditions. Their geological significance was discussed, which may provide some useful information for heat mining of heavy oil.
A SELF-ORGANIZING NERVE-TREE MODEL OF VARIOUS SEIMIC INFORMATION FOR HYDROCARBON PREDICTION
Cai Yudong, Xu Weijie
1996, 18(1): 111-116. doi: 10.11781/sysydz199601111
Abstract:
A self-organizing nerve tree model for hydrocarbon standard prediction was presented and a group of training samples were selected as study objective in the paper, in which the successful rate for prediction is 100%. Could be with high quantity, the model therefore could be a potential for hydrocarbon predition on seismic information.
MATHEMATICAL MODELLING ON THE DEVELOPMENT AND EVOLUTION OF THE PALEO-FORMATION-PRESSURE IN THE UPPER TRIASSIC, WEST SICHUAN BASIN
Xu Guosheng, Lin Zhongping
1996, 18(1): 117-126. doi: 10.11781/sysydz199601117
Abstract:
The evolution of pores and fractures, the maturation of organic matter and the development of original formation pressure (OFP) were considered in a contect, and the spatial and temproal relationships among these three aspects were discussed in this paper. It was proposed that the development and evolution of OFP could be divided into two periods, i.e. the earlier period (pri-Himalayan) and the later period (since-Himalayan). Athough there were many factors contributing to OFP during the earlier period, the hydrocarbon generation was the most important mechanism and OFP increased progressively. Accordingly, the increment of OFP in each stage was calculated. In the later.period,the great lateral squeering force in Himalayan strongly affected OFP formed in the earlier period.Therefore, the Variation of OFP by structural squeeze was semi-quantitatively represented through modelling on tectonic stress field, and the difference of the present OFP in area could be directly related to the extent of tectonic activity in Himalayan.