石油实验地质

GEOCHEMICAL CHARACTERISTICS OF THE ORGANIC MATTER IN COAL MEASURES OF DONGPU DEPRESSION, AND ITS EVOLUTIONARY PATH

Xu Huazheng

1987, 9(2): 87-97. doi: 10.11781/sysydz198702087

Abstract(975) PDF-CN(363)

Abstract:
Through the analysis and the study of organic matter in coal measures, the geochemical characteristics and the composition of the organic matter are systematically expounded in this paper. Under thermal simulation experiments, the mechanism of the hydrocarbon generation of the organic matter in coal measures is also studied. It is suggested that the organic matter of coal measures differs significantly from that of oil source rocks both in origin and in original composition.The evolutionary processes of the organic matter of coal measures are devided into three stages, i.e. immature stage (prior to brown coal); mature stage (from flame coal to coking coal); overmature stage (lean coal-anthracite).

DISCUSSION ON RELATIONSHIP BETWEEN THE DIAGENESIS OF CARBONATE SOURCE ROCKS AND PRIMARY MIGRATIONOF HYDROCARBONS IN LOWER PALEOZOIC OF SOUTH ERN CHINA

Chen Yanhua, Liu Ying

1987, 9(2): 98-103. doi: 10.11781/sysydz198702098

Abstract(1146) PDF-CN(257)

Abstract:
Based on the studies of relationship between the diagenesis of marine carbonate source rocks and the migration of hydrocarbons in Lower Paleozoic of Southern China, it is suggested that there are two different diagenesis, two carbonate source rocks, two different related conditions for the migration and the accumulation of oil/gas. Therefore,two different guidelines of peroleum exploraton are decided. The carbonate source rocks in basin area formed dominantly under compaction in a deep buried environment and they are the effective source rocks for the generation of oil and gas. The carbonate source rocks in platform mainly formed in cementation near surface environment. Since the lithification of such a kind of source rocks takes place before the migration of hydrocarbons, it lacks of primary migration of hydrocarbons and the source rocks are uneffcient. In this paper, it also points out that the occurrence of migrated bitumen is the key point and the evidence for the understanding of migration condition and path in those source rocks.

QINGLING-DABA AULACOGEN

Qin Deyu, Ji Rangshou, Gao Chanlin, Zhou Kegang

1987, 9(2): 104-113. doi: 10.11781/sysydz198702104

Abstract(2468) PDF-CN(353)

Abstract:
According to the recent studies on sedimentary, metamorphic, magmatic and volcanic formations, as well as the characteristics of later deformation stage in Qingling-Daba Area, it is believed that the aulacogen developed from Sinian to Triassic times with obvious polycycles and transversed zonation. The studied area experienced four stages of tension, faultdown, shortening and subsequent reformation. The authors of this paper suggest that the reformation also could take place during the period of formaion. As the small occeanic basins formed in Early Paleozoic within Shanxian-Erlangping region closed up by obduction, Qingling-Daba Aulacogen was shifted southward to Shanyang-Zhashui Area in late Caledonian Early Variscian. Thereafter, the aulacogen had continuously moved southward to Zhengan-Xunyang Area until the aulacogen itself ceased its aulacogenization. Qingling-Daba Area experienced the compression of horizontal Ew stress in late Indo-Chinese epoch while in late Yanshanian Himalayan, it was compressed by SN horizontal stress. The central belt of Shanxian-Erlang-ping thrusted to its both flanks in a large scale and finally the flower structures were formed.

APPROACH TO THE CALCULATIVE FORMULA FOR THE THRESHOLD VALUES OF THE EVOLUTIONARY STAGES OF ORGANIC MATTER

Zeng Daofu, Zeng Xuesi

1987, 9(2): 114-126. doi: 10.11781/sysydz198702114

Abstract(541) PDF-CN(234)

Abstract:
Connan (1974), Hood (1975), Asamhawa (1977), Jiao Shouquan and Zhou Peijun (1982) proposed the formula of the threshold values for the maturation of organic matter based on the relationship between temperature and time.In consideration of the previous works and the fact that the maturity of oil and gas in Sichuan Basin is generally high, eight calculative formulas for the threshold values of source rocks with various types of kerogen are deduced. Taking Upper Permian of Sichuan Basin as an example, the effectiveness of those formulas applied to the dynamic evolutionary process of organic matter in various major tectonic movements in Sichuan Basin is expounded. It is further indicated that for the amount on the timing of the formation of traps with respect to the formation of large amount of oil/gas, the calculative formula is viable and could provide useful in formations.

TYPES OF CONDENSATE OILS AND THEIR GEOLOGICAL DISTRIBUTIONS

Li Zanhao

1987, 9(2): 127-133. doi: 10.11781/sysydz198702127

Abstract(645) PDF-CN(301)

Abstract:
The types of condensate oils and their geochemical features are analysed in this paper. It is suggested that the condensate oil substantively is not only a product of hydrocarbon but also can be natural gasoline condensated from natural gas. The generation of condensate oil depends on the temperature, pressure and the compositions of hydrocarbons within the individual evolutionary stages of organic matter under a favourable condition.

THE GEOLOGICAL CHARACTERS OF THE TIGHT OIL/GAS RESERVOIRS IN DAANZHAI SECTON NORTHERN SICHUAN AND THE EXPLORATION TECHNIQUE FOR IT

Wang Dangqi

1987, 9(2): 134-143. doi: 10.11781/sysydz198702134

Abstract(646) PDF-CN(376)

Abstract:
Coquina is the main reservoir rocks in Daanzhai Section of northern Sichuan,but its porosity, permeability and pore geometry are quite poor. The secondary dissolution pores, caves and fractures constitute most of the space for the storage and accumulation of oil/gas. The main type of the facies of oil/gas pools is shelly bank with nonstratified and inhomogeneous characters. The shelly bank facies controls the enriched oil/gas zones. The local structures and fractures formed in the later stage of the tectonic movement did not rework much the shelly bank oil/gas pools and did not significantly redistributed the previously formed oil and gas pools. Therefore,the exploration of commecial oil/gas pools in the section of northern Sichuan should be focused on the main body of the shelly bank located in the interior zone of shallow water lacustrine facies surrounding the sub deep-deep water la-custrine facies of the oil-generative depression.

A BREAKTHROUGH OF DIVISION AND CORRELATION OF THE LOWER TERTIARY SYSTEM OF SOME BASINS IN HENAN PROVINCE

Wang Congfeng, Zhang Xiaojun, Wang Jingzhe, Wu Jianzhuang, Fu Maolan

1987, 9(2): 144-150. doi: 10.11781/sysydz198702144

Abstract(554) PDF-CN(287)

Abstract:
The systematical studies of the Lower Tertiary strata of various inland basins in Henan are made in this paper. The Lower Tertiary System bears rich fossils, such as Ostrcoda, Sporo-pollen, Algae, Bivalves, Gastropoda, Charophyta Mammalia, etc., In algae fossil assemblages, the main compo-nents are Deflandrea, Bohaidina, Parabohaidina, Conicoidium, Leiospaevi-dia, Rugasphaera, Campenia and Pediastrum, etc., According to abundant algae fossils discovered in Lower Tertiary System in Miyang Depression, Xiangcheng Depression, Wuyang Depression, Tongben and Banqiao basins, it is believed that these regions would be in an environment of lacustrine facies with short inundation.

PRELIMINARY STUDIES ON THE DIAGENESIS OF FUYU OIL PLAY IN FUYU-XINLI AREA OF SOUTHERN SONGLIAO BASIN

Bai Yurun

1987, 9(2): 151-163. doi: 10.11781/sysydz198702151

Abstract(486) PDF-CN(326)

Abstract:
Fuyu Oil Play belongs to the 4th Member (K₁q⁴) of Quantou Formation, Songhuajiang River Group of Cretaceous. It is one of the major plays in the southern Songliao Basin, After the examination on numerous thin sections of rocks, the following understandings on the diagenesis of the oil play have been achieved. 1. Fuyu Oil Play is a suit of rhythmic sediments composed of sandstones, siltsands, claystones and the transitional types between the above rocks with a total thickness of 100 meters. The sandstones of this area rich in feldspar lithic debris, characterized by low maturation of mineral composition. 2. The compositions and the textures of the sandstones control the physical and chemical diagenesis. 3. After its deposition, the oil play has experienced multiple diagenetic changes. According to the metasomatic alterations of diagenetic changes observed on thin sections, the conditions essential to physical and chemical diagenetic changes, the control of depositional environment on diagenetic environment and the general trend of diagenesis, the sequence of the various diagenetic changes can be determined. 4. The diagenesis of this area can be divided into three stages, i.e. the stage prior to effective bural, shallow burial stage and deep burial stage. 5. The authigenic kaolinites, quartz and calcites are the three kinds of major cements which extensively influenced the reservoir petrophysics.They are especially well developed in the sandstones which are somewhat coarse-grained with higher primary porosity and good pore interconnection. 6. The SiO₂ of the authigenic quartz cements is principally derived from the slow dissolution and kaolinization of feldspar and starting from the early stage of diagenesis. The late overgrowth and mosaicism of quartz are less important.

THE FORMATIVE CONDITIONS OF THE COAL GAS OF WANGJIAHE GAS FIELD, KAIPING SYNCLINE

He Haiquan, Zhang Wenhui, Zhou Xingtai

1987, 9(2): 164-173. doi: 10.11781/sysydz198702164

Abstract(502) PDF-CN(263)

Abstract:
Wangjiahe Gas Field is a typical nonconventional coal gas pool. The formative conditions for such a gas pool, including the source of the gas, reservoir, cap, trap and its timing are studied and analysed. It is hoped that this presentation would call forth valuable opinions on searching of coal gas, especially the thin seam coal gas.

AN ESTIMATION OF THE STRESS VALUES DURING MINERALIZATION FOR THE ANTIMONY OREFIELD IN XIKUANGSHAN, HUNAN PROVINCE

Ji Rangshou

1987, 9(2): 174-180. doi: 10.11781/sysydz198702174

Abstract(493) PDF-CN(247)

Abstract:
Based on the certain structural style developed in Xikuangshan Area, Hunan Province, the stress values of mineralization are preliminarily estimated by mathematic mechanics in this paper. It reveals that the estimation of the stress values can be correlated to that of Paleo-stress values by other structure geologists using other methods. Therefore, it would be helpful for the discussions both on the various structures and the distributive mechanism of the ore deposits developed during mineralization in Xikuang shan Area.

INFLUENCE OF MINERAL MATTER ON DTA THERMOGRAM OF KEROGEN

Wang Zheng, Wang Linping

1987, 9(2): 181-186. doi: 10.11781/sysydz198702181

Abstract(546) PDF-CN(247)

Abstract:
Aiming at the study on the influence of mineral matter on DTA ther-mogram of kerogen, experiments with various minerals were carried out. The experiments show that. 1. coal, kerogen, bitumen and petroleum all have their own diagnostic peaks on DTA thermograms which could serve as a simple and reliable way to study the maturity of organic matters; 2. mineral matter, especialy pyrite, exert significant influences on DTA thermogram, but if the content of pyrite is less than 2‰ after dilution (i.e.the pyrite content in kerogen is less than 20%), it could be accepted within the permitted range of the sensitivity of the instrument, and there is no influence on the result.

THE ORIGIN AND THE GEOCHEMICAL SIGNIFICANCE OF THE ACIDOLYTIC HYDROCARBON GAS IN CARBONATE ROCKS

Ye Jun, Cao Huiti

1987, 9(2): 187-194. doi: 10.11781/sysydz198702187

Abstract(522) PDF-CN(200)

Abstract:
The origin of the acidolytic hydrocarbon gas in carbonate rocks and its geochemical significance are studied in this paper. The study shows that aci-dolytic hydrocarbon gas represents the gas bound in carbonate minerals. Its origin is rather complicated and is affected by various factors among which epigenesis is the most outstanding one. In addition, according to the analysis and the study of its geochemical characteristics, the content of the acidolytic hydrocarbon gas bears no relation to the abundance and the maturity of the organic matter of the source rock, as well as to the lithology and the texture of the source rock. These facts underline the complex nature of the acidolytic hydrocarbon gas.

1987 Vol. 9, No. 2

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