1990 Vol. 12, No. 4

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THERMAL EVOLUTION OF THE CARBONIFEROUS-PERMIAN COAL SERIES IN THE NORTH CHINA PLATFORM AREAS AND ESTIMATION OF PETROLEUM PROSPECTING
Zhang Shiya
1990, 12(4): 345-352. doi: 10.11781/sysydz199004345
Abstract:
The metamorphic zone of coal series in Carboniferous-Permin of the north China Platform are divided using abundant data of vitrinite reflectance. The burial depth and geotemperature are important factors which have a dominant influence over thermal evolution. Petroleum generation in coal series is closely related to the metamorphic zone of coal series. The Permian-Triassic coal series in the moderately-highly metamorphized zones usually have an early generated petroleum which would have been lost unless there are any good covering strata; while the moderately-highly metamorphic Cenozoic zones and their neibouring areas have a late generated petroleum, and they usually have promising prospects.
CLOSING OF EASTERN QINLING PALAEOOCEAN AND COLLAGING BETWEEN THE NORTH CHINA AND YANGTZE BLOCKS
Ji Rangshou, Qin Deyu, Gao Changlin
1990, 12(4): 353-365. doi: 10.11781/sysydz199004353
Abstract:
Eastern Qinling Palaeoocean is one developed in late Proterozoic and closed during Silurian-Devonian(420-400Ma). At the late stage of closing, collage between the north China and Yangtze plates took place, which did not end until Carboniferous (340Ma).The northern part of Qinling Palaeoocean (the southern margin of the north China plate) was turned into an active continental margin with a system of trench-island arc-back arc basin formed from late Ordovician, but its southern part (northern margin of Yangtze plate) remained a passive continental margin. The two kinds of continental margins mentioned above had been collaged from Devonian until Carboniferous. With the basis of the following informations: the tectonic assemblage and its collacative relations of major nappes; the inversion of metamorphic facies and the characteristics of strain markers within the nappe sheet and the measurements on strain parameters (the nappes developed during 420-340Ma); and the studies of foreland basin, the tectonism of the north China and Yangtze blocks is a collisional collage accompanied by obduction and a dextral shearing.
NAPPING OF LONGMENSHAN TYPE AND ITS SIGNIFICANCE IN PETROLEUM EXPLORATION
Zhang Guanqun
1990, 12(4): 367-374. doi: 10.11781/sysydz199004367
Abstract:
The cavalcades of tectonics and sedimentation in Longmenshan area are discussed. There exist nappes of different times and in opposite directions, i.e: during late Triassic-early Jurassic, the area used to undergo a westward napping; while from the late period of late Tertiary until recent time, an eastward napping are predominant. Here we call this eastward type of nappes Longmenshan type. Areas favourable for petroleum exploration can be found under the eastward nappes, and still more promising areas are those beneath early formed nappes.
THE DEVELOPMENT AND APPLICATION OF FINGERPRINT PARAMETERS FOR HYDROCARBONS ABSORBED BY SOURCE ROCKS AND LIGHT HYDROCARBONS IN NATURAL GAS
Hu Tilin, Ge Baoxiong, Chang Yigang, Liu Bin
1990, 12(4): 375-394. doi: 10.11781/sysydz199004375
Abstract:
Among the fingerprint parameters of light hydrocarbon,indexes of MCH and CA are developed and selected as optimum parameters for parent material type and maturity, respectively, by studying the characteristics of hydrocarbons absorbed by source rocks and light hydrocarbons in natural gas. Applying these parameters, we can identify the types of natural gas and source rocks as well as determine maturity; and make direct correlations of gas/gas and gas/source rock. This new method is considered as n efficient, simple and economical measure in identifying the origin of natural gas and estimating gas source rocks.
GEOCHEMICAL CHARACTERISTICS OF TERNARY EXTRACTS
Zhou Leifeng, Wang Rongfu
1990, 12(4): 395-406. doi: 10.11781/sysydz199004395
Abstract:
Ternary extracts reffer to those soluble orgaic matters resulted from continuous extraction with ternary solutions (benzene, methanol, acreton) after a rock sample being extracted with chloroform. The authors mainly discuss about these extracts and heavy components,thereby to get a more precise and complete understanding of the primary organic matters.
1990, 12(4): 406-406. doi: 10.11781/sysydz199004406
Abstract:
LOGGING RESPONSE MODEL FOR LAVA FLOW UNIT
Dong Dong
1990, 12(4): 407-411. doi: 10.11781/sysydz199004407
Abstract:
In order to establish corresponding logging facies model, the regular correlations between geofacies of various lava flows and logging response characteristics were defined with the basis of the study of the geofacics model of lava flows and the practical logging exploration data from Weibei depression(in Shandong province).Furthermore, the correlative statistical relations of △t (acoustic time) and p (density) with primary porosity of lava were obtained,and an expression of achieving the pore contents of lava was proposed. Thus, logging data can be applied to identify and divide the litho-facies members of downhole lava reservoirs and to make qualitative interpretation of their physical properties, and to predict and evaluate favourable reservoirs.
APPLICATION OF FLUID INCLOSION METHOD TO THE EVALUATION OF HYDROCARBON POTENTIAL IN JUNGAR BASIN
Pan Changchun, Zhou Zhongyi
1990, 12(4): 412-420. doi: 10.11781/sysydz199004412
Abstract:
The fluid inclosion petrography and thermometry of quartz vein and quartz-calcite vein from two boreholes and a Carboniferous surface section in Jungar basin were studied. By combined use of vitrinite reflectance data, the thermal history, hydrocarbon formation and evolution of source rocks in the basin were discussed in detail. Furthermore, the thermometry of fluid iuclosion with quartz-calcite vein and its geological significance were reviewed.
IS VITRINITE REFLECTANCE THE GENERAL CRITERION OF MATURATION?
Guo Dixiao, Feng yuanzheng
1990, 12(4): 421-425. doi: 10.11781/sysydz199004421
Abstract:
Through thermal simulation experiments on organics of different types, the authors found that there were much difference in vitrinite reflectance for different organics subjected to same thermal evolution. The difference for R°could reach as much as 0.24-0.60 with same thermal gradient. At low thermal stage (360℃), the values of R° for type I were lower than those for type Ⅲ;and at high thermal stage, with contrary results come about. This phenomena tallies with the observations from field sections, suggesting that vitrinite reflectance is influenced by the type of parent material. In view of above-mentioned facts,vitrinite reflectance as a general "criterion" for maturity can be applicable only for the same kind of organics, but it is difficult to use it in comparisions of different types of organics, therefore it can not be taken as a general "criterion", and correction need to be made.
IMPROVEMENT ON STUDY OF ORGANIC TYPES AND MATURATION WITH ORGANIC PETROLOGY
Chen Jianyu, Hao Fang
1990, 12(4): 426-431. doi: 10.11781/sysydz199004426
Abstract:
Forty-three samples of kerogen and inclusions in coals from two basins in China were studied for organic petrology.By combined use of transmissible, reflective lights and fluorescence, the quantification of macerals, the determination of fluorescence spectra and vitrinite reflectance,plates for the relations between fluorescence parameters and vitrinite reflectances were accomplished. The results show that there are some defects in the methods of determing kerogen types by current indexes. Amorphous-dominated kerogen may belong to any chemical type, while its hydrogen enrichment depends on the source of organics, the sedimentary environments and early diagenesis. The fluorescence method can be used to distinguish amorphous kerogen enriched hydrogen from that of poor hydrogen effectively, and to establish the relation between optical classification and element analysis for kerogen) besides, some kerogen samples have very low values of vitrinite reflectance, being unable to reflect organic maturity. But fluorescence parameters can make some remedies about this defects of R°and develop relational plates between fluorescence parameters and R°, and infer the values of vitrinite relectance.
DIFFERENTIAL STUDY ON VITRINITE REFLECTANCE OF MACERALS FROM COAL AND KEROGENS OF DIFFERENT HOST ROCKS
Wu Baojun, Zhao Shiqing
1990, 12(4): 432-437. doi: 10.11781/sysydz199004432
Abstract:
The influence of hostrock petrofacies on vitrinite reflectance for organic elastics is an important problem in the study of thermal evolution of organics. The coal in coal-bearing strata and kerogens in several dominant rocks of Carboniferous-Permian in Huaibei (north Anhui) were measured for vitrinite reflectance, moreover the methods of data process and value determination for vitrinite reflectance of despcrsed organics were also studied. The results show that the vitrinite refleetance in kerogen from mudstone, sandstone, limestone differ from that of coal in the same horizon by +6 — -10%,-1 — -16% and +4 — -14%, respectively, which means that the data process and value determination for vitrinite reflectance are more important than the reflectance determination itself.
LATE TRIASSIC SPORE-POLLEN AND ACRITARCHS IN JIEZA GROUP, SOUTHERN QINGHAI PROVINCE
Ji Liuxiang, Wang Congfeng
1990, 12(4): 438-447. doi: 10.11781/sysydz199004438
Abstract:
Abundant spore-pollen and Acritarchs are found in Jieza Group (southern Qinghai), altogether 51 genera, 70 species, including a species nov.. The microfossil assemblage is made of fernlike spores (45%); Gymnos-permous pollens (34%) 5 Acritarchs (21%).Major spores consist of Apiculatisporis (7.9%), Punctatisporites (6%); Dictyophllidites (3.7%); Raistrickia (3.6%); Lycopodiacidites (2.7%); Lophotriletes(2%); Concorisporites (1.5%); Marattisporites (1.5%); Vndula tisporites (1.2%), etc.. Pollens are mainly composed of Chordasporites(6.5%), Psophosphaera (3.9%) 5 Ovalipollis (3.6%); Pinites (2%); Caytonipollenites (2.7%); Cycadopites(3.9%),etc.. Dominant Acritarchs are Micrhystridium(9.1%), Brocholaminaria (2.2%), Laminarites (1.2%).etc.. The geological age of those microfossils is late Triassic.