1987 Vol. 9, No. 3

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CHEMICAL COMPOSITION AND STRUCTURAL CHARACTERISTICS OF KEROGEN AND THEIR CORRELATION TO THE CLASSIFICATION PARAMETERS……GEOCHEMICAL STUDY ON THE UPPER PALEOZOIC KEROGENS OF JUNGGAR BASIN
Li Jinchao, Huang Difan, Zhang Dajiang
1987, 9(3): 195-210. doi: 10.11781/sysydz198703195
Abstract:
It is most important to make correct iden ification of kerogen types and to judge properly the interrelations among the type parameters, so as to correctly assess oil generation potential and its resources. We have reported the study on type parameters of Tertiary kerogen in Eastern China. In this paper, using the analytical data of element composition, Rock-Eval, infrared spectrum, carbon isotcpic composition, pyrolysis gas chromatography, and X-ray diffraction, the chemical composition and structural characteristics for the Upper Paleozoic kerogens of Junggar Basin, and the interrelation among various types of parameters are studied. Some boundary values of kerogen classification are corrected and a few new parameters are added. In the end of this paper, geochemical parameters of kerogen types are compiled in a table which can be regarded as basis for correct classification of kerogens.
APPROACH ON GEOLOGICAL CONDITIONS FOR THE FORMATION OF OLL AND GAS FLOW OF INORGANIC GENESIS, AND THE GUIDELINE FOR ITS EXPLORATION IN WESTERN SICHUAN BASIN
Fu Xiao
1987, 9(3): 211-217. doi: 10.11781/sysydz198703211
Abstract:
With large amounts of analytical data on oil and gas, the author approciates and supports the deep inorganic genesis theory of oil and gas, in which it is suggested that the upwelling liquid-gas materials are the source material of oil and gas. Deep fractures are the channels for the source material and the poremembrane network connected with deep faults is the reservoir space for oil and gas, sheltered traps are formed in various rock series with relative low permeability. Futhermore, according to the geological conditions for the formation of oil and gas of inorganic genesis, an inorganic genesis model of oil and gas, and the guideline for oil and gas exploration in western Sichuan Basin are discussed in this paperd.
THE DIAGENESIS AND RESERVOIR PROPERTIES OF SILURIAN CLASTIC ROCKS IN THE SOUTHERN MARGIN OF YANGTZE PARA-PLATFORM
Luo Ruilan, Wang Shoude, Zheng Bing
1987, 9(3): 218-227. doi: 10.11781/sysydz198703218
Abstract:
The diagenesis on the sandstones bitumen bearing in certain regions and sections of the southern margin,Yangtze Para-platform is discussed in this paper. It is suggested that the diagenesis in Majiang Anticline Belt is dominated dy early stage dolomite cementation and by the corrosion and replacement of dolomite in clasts. The late Guangxi movement caused the formation and then the successively upliftings of the anticline in the area. The axis of the anticline was eroded and eluviated by atmosphere fresh water, resulted the development of secondary pores in dolomites, which would be favourable for oil/gas accumulations. The maturities of sandstone minerals in the eastern flank of Majiang Anticline, Wuxi, Changshu and Huangqiao areas are rather high and the diagenesis are mainly quartz overgrowth and kaolinites filling the primary pores. The bitumen was filled into the residual primary pores of quartz overgrowth,so that the accumulation of oil/gas is unfavourable and poor. The Middle-Lower Silurian sandstones in a large area of Anjikang Mountains and lower section area of Yangtze River are observed as mosaicism of clasts and clay matrix fillings which are resulted by severe mechanical compaction, since the content of metamorphic debris is quite high and the heavy load-press of overlain strata. That is why the oil/gas accumulation in such a sandstone area is poor and only vein bitumen controlled by fractures can be formed.
APPLICATION OF SEISMIC STRATIGRAPHY TO YANGJIANG DEPRESSION
Yang Aitang
1987, 9(3): 228-239. doi: 10.11781/sysydz198703228
Abstract:
In this paper, seismic stratigraphy is applied to interpret the sequences, structural characteristics and depositional facies in Yangjiang District, and the oil/gas prospects are evaluated as well. Ⅰ. Based on the seismic stratigraphic analysis, the Meso-Cenozoic sequences in the depression can be divided by two erosional hiatus, two truncations, three onlaps and a toplap unconformity. Ⅱ. According to the configurations and patterns of the seismic reflections, it is revealed that some growth normal faults developed in the depression. with rolling anticlines and antithetic normal faults during Meso-Cenozoic times there Then, the depression was transformed into a "V" shaped extensional basin by the successive tractions. Ⅲ. Nine types of seismic facies units are classified and the depositional facies belt are established based on the integrated analysis of seismic reflection configurations, structures, and reflective amplitudes combined with other informations. Ⅳ. According to the distribution of strong phase amplitude anomalies ("facies surface"), the possible oil-gas prospects are predicted without the analysis of seismic velocity and frequency.
APPLICATION OF TRIDIMENSIONAL FULL RANGE SCANNING FLUORESCENT SPECTROSCOPY TO MARINE PETROLEUM EXPLORATION
Zhu Guihai, Jame M. Brooks
1987, 9(3): 240-249. doi: 10.11781/sysydz198703240
Abstract:
The tridimensional full range scanning fluorescent spectroscopy is a new technique developed in 1980s. The tridimensional spectra are composed of emissive wave length, excited wave length and fluorescent intensity and can be expressed as intensity contours, or digital lists describing the concentration of measured components. This new technique can not only improve the measuring sensitivity and the selectivity of molecular structures, but also can directly measure complicated mixtures. The authors of this paper use this technique and measure the aromatic hydrocarbons extracted from sea-water, marine sediments and marine biota. Applying the ratio "R" between the fluorescent intensities and the fluore-scent intensity of a definite wave length, the geochemical exploration was effectively carried out and provided important informations for the evaluation of regional potential of oil/gas and the prediction of oil/gas type.
1987, 9(3): 250-250. doi: 10.11781/sysydz198703250
Abstract:
THE PROSPECTS FOR OIL AND GAS, AND THE SEDIMENTARY SEQUENCES FROM TRIASSIC TO JURASSIC IN TARIM BASIN
Cheng Ronglin
1987, 9(3): 251-258. doi: 10.11781/sysydz198703251
Abstract:
The sedimentary sequences of Triassic-Jurassic systems in Tarim Basin can be grouped into 4 types of depositional facies and 12 types of depo-sitional subfacies. The possibility of sea-water overflowings in the area during Middle-Late Jurassic time is discussed in this poper. Thereafter, the prospects for oil and gas resources and the exploration guideline for Triassic-Jurassic sequences is suggested.
1987, 9(3): 258-258. doi: 10.11781/sysydz198703258
Abstract:
DIAGENETIC CHARACTERS OF MIDDLE-LOWER JURASSIC SYSTEMS AND THE DENUDED THICKNESS OF OVERLYING SEQUENCES IN LIUZHILANGDAI AREA, GUIZHOU PROVINCE
Hu Weiyuan, Liu Shuhui, Zou Zhifu
1987, 9(3): 259-266. doi: 10.11781/sysydz198703259
Abstract:
The diagenetic characters and the diagenesis stages of Middle and Lower Jurassic mudstones, Zhiliujin Group quartzose sandstones and Shaxi For-mation feldspathic sandstones in Liuzhilangdai Area, Guizhou Province are described in this paper. Since the denuded sequence would influence on the underlying strata before the denudation,some diagenetic marks would be surely remained in the residual strata. According to the analysis of the diagenetic marks and the correlation to relative diagenetic marks in certain known burial depth area, the thickness of denuded strata are deducted as 1800 meters in this area.
DISCUSSION ON PEAK OIL GENERATION THRESHOLD
Sheng Zhiwei
1987, 9(3): 267-271. doi: 10.11781/sysydz198703267
Abstract:
On the basis of thermal simulation data of different types of kerogen, the author of this paper proposes the hydrocarbon yields of source rocks during the stage from maturity threshold to peak oil generation, i.e. 14.07% for kerogen Ⅰ, 16.50% for kerogen Ⅱ and 18.28% for kerogen Ⅲ. Most of the hydrocarbons were generated after the stage when peak oil generation have been reached. Taking Bi Well No.08 in Biyang Depression as an example, hydrocarbon generation pattern is fundamentally consistent with the results of thermal simulation mentiond above.
THE PROTOTYPES OF LATE PALEOZOIC PETROLIFEROUS BASINS IN LOWER SECTION AREA OF YANGTZE RIVER
Ding Daogui, Li Ping, Lü Junxiag
1987, 9(3): 272-282. doi: 10.11781/sysydz198703272
Abstract:
The characters of deposition and subsidence in lower section area of Yangtze River are discussed in this paper.The authors of this paper point out that the pre-Cambrian basement in the area is composed of Paleo-core, Qiantang Arc Rising Belt and Cathaysia. Firstly, Dongan-Jinning movement cratonized the Yangtze Para-platform and the Caledonian movement ceased the developing stage of trough-platform(graben), and then transformed into the developing stage of cratonic syneclise depressions and basins. In this paper, the characteristics of Late Paleozoic protobasins are described in detail.The structure zones are classified and divided into three developing stages, depending on the structure evolution history,i.e. faultdown, depression and transformation stages. Indosinian-Early Yenshan movement is a major event which reworked the Late Paleozoic basins and resulted the intraplate deformation of severe foldings and nappings, trending from southeast to northwest in the Paleozoic sequences. The deformation pattern mainly is basement decoupling and the foredeep depressions formed at fore-nappings. Such a movement reworked Late Paleozoic intra-plate depression,and superposed and preserved the depression as well.All of these mentioned undoubtedly would provide favourable conditions for the Paleozoic oil/gas generation and accumulation and in addition, the petroli-ferous prospects in Meso-Cenozoic foredeep depression also can not be ignored.
DISCUSSION ON THE PROBLEMS OF THE MEASUREMENTS AND INTERPRETATION OF MERCURY WITHDRAWN CAPILLARY PRESSURE CURVES
Liu Yulong
1987, 9(3): 283-286. doi: 10.11781/sysydz198703283
Abstract:
In this paper, the influence of the lower pressure limit of the instrument on the efficiency of the mercury withdrawn under low expulsion pressure is discussed, based on the experimental data combined with theoretical analysis. Thereafter, the author points out the problems in the measurement of size distribution of pore throats using mercury withdrawn curves and proposes a new method of mercury repressure curves to determine the size distribuion of pore throats. Finally, a simplified method of "sequentially reducing pressure mercury withdrawn curves" is presented.
THE STRUCTURE OF KEROGEN AND ITS ALTERATION
Lin Zongnan, Zhu Meiqian
1987, 9(3): 287-298. doi: 10.11781/sysydz198703287
Abstract:
Based on thermal simulation and various analytical experiments, the authors have made a deep research on the structure of kerogen, which shows. 1. the oxygen-enriched type of kerogen possesses inner catalytical effect which exceeds that of clay minerals. 2. aging and alteration of the primary structure of kerogen took place during geological history, many heteroatomic chains of kerogen broke down, and the rate of thermal degradation was reduced. This study provides theoretical evidence for studying mechanism of thermal degradation of Kerogen.