2002 Vol. 24, No. 3

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CURRENT HYDROCARBON EXPLORATION SITUATION AND TACTICS IN THE HEFEI BASIN
LI Pi-long, LI Xue-tian, LOU Jian-qing, XU Chun-hua, LIU Zhong-quan
2002, 24(3): 195-199. doi: 10.11781/sysydz200203195
Abstract:
Since 1958,the exploration and study of oil and gas in the Hefei Basin was engaged by more than 10 units. The exploration history of the Hefei Basin is divided into 4 stages. At present, the Hefei Basin is still in its primary stage of basin exploration, and many basic questions of petroleum geology are still unsolved. The integrated studies of petroleum geology in the course of oil and gas exploration should be strengthened in the basin, and main task of drilling is still to solve some basic problems of petroleum geology in the basin. The result of synthetic studies showed that the Eogene of the Shucheng Depression in the basin might be a potential target for the success of hydrocarbon exploration.
RESEARCH METHOD ABOUT THE PROTOTYPE RESTORATION AND HYDROCARBON EVALUATION OF THE HEFEI BASIN
CHEN Gang, LI Pi-long, LI Xue-tian, YAN Han-jie, LIU Ai-yong, TAN Ming-you, JIA Hong-yi
2002, 24(3): 200-203. doi: 10.11781/sysydz200203200
Abstract:
Based on the critical problems presently existing during the study of the Hefei Basin and the late research trend of related subject domains, the basic principles, the research train of thought and the corresponding multiple-subjects-combined research method for the prototype restoration and hydrocarbon evaluation of the basin were comprehensively analysed and discussed. It was emphasized that the study of the Hefei Basin must insist on the basic principles of overall, dynamic and comprehensive analyses. The multiple-subjects-combined comprehensive research method, which combining the former and modern structural analysis of the basin with the evolution of orogenic belts, the restoration of original basins with the dynamic prediction of hydrocarbon accumulation and geology with geophysics, was used to completely reveal the original geologic structure of the Hefei Basin and the characteristics of its formation, evolution and multicycle complex reconstruction, the formation-reconstruction-occurrence environments of hydrocarbon accumulation factors in the different evolutionary stages of the basin, and their space-time matching relation to hydrocarbon accumulation. Besides, the advantageous hydrocarbon accumulation-preservation units and the favorable exploration targets of the Hefei Basin were predicted objectively.
STRUCTURAL STYLES AND EVOLUTION IN THE HEFEI BASIN
DING Li-rong, LIU Zhong-quan, LEI Min, PEI Lei
2002, 24(3): 204-208. doi: 10.11781/sysydz200203204
Abstract:
The Hefei Basin is located in the connection of the North China Platform, the Yangtze Paraplatform and the North Huaiyang Fold Belt, and was long influenced by the Dabie Orogenic Belt and the Tanlu Fault. The structural evolution can be divided into two stages including the formation of basinal basement and the development of the basin. The basin mainly underwent the thrusts during the Indosinian, Late Yanshanian and Early Himalayan movements, and two extensional movements were developed during the Early Yanshanian and Early Himalayan activities. Four structural styles, i.e., compression structure, extensional structure, negative inversion structure and strike-slip faults, were developed as a result of the tectonic movements mentioned above. A systematic study on the structures of the basin will provide information for petroleum exploration in the basin.
TECTONIC CONTROL OF THE DABIESHAN OROGENIC BELT OVER THE HEFEI BASIN
SONG Ming-shui, JIANG Lai-li, LI Xue-tian, CHU Dong-ru, DU Sen-guan
2002, 24(3): 209-215. doi: 10.11781/sysydz200203209
Abstract:
The North Huaiyang Structural Belt is composed of a series of thrust slices up to north, and is the transitional zone between the Dabieshan Orogenic Belt and the Hefei Basin. It underwent two generations of thrusting of the Early Yanshanian and the Late Yanshanian. The Early Yanshanian structure is characterized by back detachementing and front thrusting, and the Late Yanshanian one is expressed by regional extruding and thrusting up to north. The Hefei Basin underwent two generations of subsidence including depressions and faulted sags. The depression is controlled by uplifting of the Dabieshan Mountain caused by subducting of the basement of the Yangtze Continental Block, and the faulted sag is affected by the divergence uplifting. They show a good tectonic coupling relationship. The Shucheng Depression in the southeastern part of the Hefei Basin is a tectonic favorable area for oil and gas exploration.
A RELATIONSHIP BETWEEN THE TAN-LU FAULTED BELT AND THE PETROLEUM GEOLOGY OF THE HEFEI BASIN
LU Guo-ming, ZHU Guang, LI Xue-tian, WANG Dao-xuan, SONG Chuan-zhong, LIU Guo-sheng
2002, 24(3): 216-222. doi: 10.11781/sysydz200203216
Abstract:
According to isotopic dating, sinistral displacement of the Tan-Lu faulted zone took place in the Early Cretaceous. The movement offset sinstrally the Dabie-Jiaonan Orogenic Belt. The displacement of the faulted zone controlled the development of the strike-slip basin in the eastern part of the Hefei Basin in the Early Cretaceous. The strike-slip basin was filled with deposits of the Zhuxiang Formation. Dark mudstone with a total thickness of 600m was deposited in the environment of deep lakes in the Early Cretaceous strike-slip basin. During extensional movement of the Tan-Lu Fault from the Late Cretaceous to the Paleogene, a faulted half-graben basin was developed in the eastern part of the Hefei Basin. It was filled with the Xiangdaopu and Zhangqiao Formation of the Late Cretaceous and the Dingyuan Formation of the Paleogene. Dark mudstone was found in the Xiangdaopu and the Dingyuan Formation, and that from the Dingyuan Formation in the Shucheng Depression has better quality. With compression movement in East China and thrusting activities of the Tan-Lu faulted zone since the Neogen, the Hefei Basin terminated its development. In terms of hydrocarbon exploration, more attention should be paid to the Shucheng and the Daqiao Depression.
CHARACTERISTICS OF THE MESOZOIC STRATA IN WELL AN’CAN-1 OF THE HEFEI BASIN
XU You-de, ZHAO Ming, XU Chun-hua, XU Ming, QIU Lian-gui
2002, 24(3): 223-227. doi: 10.11781/sysydz200203223
Abstract:
The classification of strata has a great effect on the knowledge about structural evolution, sedimentary environment and even evaluation of hydrocarbon potential in a basin. This paper discussed the characteristics of the Mesozoic stratigraphy in well An'can-1 based on lithology, logging response and seismic reflectance. The framework of the Mesozoic stratigraphic sequence was set up, which is meaningful for the appraisal of hydrocarbon potential in the Hefei Basin.
THE MESOZOIC DEPOSITIONAL FACIES AND RESERVIOR CHARACTERISTICS OF WELL AN’CAN-1 IN THE HEFEI BASIN
QIU Lian-gui, XIN Zhong-bin, XU Chun-hua, XU You-de
2002, 24(3): 228-231. doi: 10.11781/sysydz200203228
Abstract:
Well An'can-1 is the first stratigraphic well drilled in the Hefei Basin by Shengli Oilfield Co. Ltd. The depositional facies and reservoir characteristics of the Mesozoic were discussed based on the rock mineralogy and geophysical properties of the sequence. It showed a progradation for the Mesozoic sedimentation fron top to bottom with lake deposit in the Early Jurassic to ineterbedded lacustrine and fluvial deposit or fluvial deposit in the Middle and Late Jurassic to fluvial facies in the Early Cretaceous. The reservoirs in the Mesozoic sandstones were poor and were dominated by very low porosity and permeability. They may be effective reservoirs for gas accumulation.
CHARACTERISTICS OF GRAVITY FIELD IN THE HEFEI BASIN
JIA Hong-yi, LÜ Xi-xue, LI Yun-ping, YAN Han-jie, HU Jia-shan, LIU Guo-hong, ZHANG Yun-yin
2002, 24(3): 232-242. doi: 10.11781/sysydz200203232
Abstract(1189) PDF-CN(518)
Abstract:
The geologic structures is very complex and the surface is a crisscross network of gullies in the Hefei Basin. The basement, faults and structural framework of the basin were revealed in accordance with the object-oriented processing of gravity anomaly. The basin can be divided into four different structural belts,i.e., the foreland thrust fold belt, the Shucheng foredeep belt, the Liu'an fore-bulge fault-wrench belt and the Feibei back-bulge slope belt based on integrated gravity,magnetic, electric and seismic data. The prospects for petroleum exploration in the basin were briefly discussed.
MAGNETIC CHARACTERISTICS OF THE HEFEI BASIN
DONG Bo, ZHANG De-run, LI Xue-tian, LIU Ying-hui, CHEN Bin, YU Yong-sheng, WANG Jue-fu, LI Shu-qin
2002, 24(3): 243-249. doi: 10.11781/sysydz200203243
Abstract:
Abundant geologic information was obtained in the Hefei Basin by high-precision aeromagnetic survey. On this basis,the relief morphology of bedrock in the area was outlined, the faulted structural and regional structural units were divided, and the lithofacies structure of the basement was discussed. Besides, the regional structural anomalies were outlined, classified and interpreted. At last, the petroleum prospects were predicted, and the further exploration direction in the area was pointed out.
ELECTRICAL CHARACTERISTICS OF THE HEFEI BASIN
ZHANG Sheng-ping, WANG Qi-nian, ZHANG Jiao-dong, ZHAN Shuang-qing, LI Xue-tian, WANG Chuan-qi, ZHAO Jian-hua
2002, 24(3): 250-254. doi: 10.11781/sysydz200203250
Abstract:
The electrical data of the Hefei Basin revealed that a) the caprock resistivity of the basin is lower on the whole, E and K are low-resistance strata, and the Jurassic is relative high-resistance strata; b) the electrical properties of basements are greatly different: the Upper Paleozoic which is widely developed in the southern part of the basin is low-resistance strata,the Lower Paleozoic is relative high-resistance strata, and the Proterozoic and other old strata are high-resistance strata; c) a near-WE distributed and uplift-depression alternated structural system was formed in the basin through many times of NS compression and extension during the Indosinian and Yanshanian periods, and a EN structural zone was developed in the Himalayan period along with the activation of the Tanlu Faulted Belt; d) near the Shucheng Fault is the conjoint belt of the Dabie Block and the North China Platform with the North China Platform subducting under the Dabie Block; e) the Upper Paleozoic sedimentary basin which might be covered under the nappe on the southern side of the basin may be of important geological significance in the oil and gas exploration.
CHARACTERISTICS OF VELOCITY FIELD IN THE HEFEI BASIN
LIU Cheng-zhai, ZHAO Zong-ju, YI Wan-xia, SUN Shu-hai, LI Xie-tian, SHEN Jin-long
2002, 24(3): 255-260. doi: 10.11781/sysydz200203255
Abstract:
Based on the results of well shooting and seismic pre-stack depth migration processing, the velocity field of sedimentary layers in the Hefei Basin showed complex difference. The velocity was mainly controlled by the buried depth and lithology of sedimentary layers. The Jurassic,especially the Lower Jurassic showed high interval velocity with 5 000-6 000m/s, indicating deep burying and compact lithology. The interval velocity in the Middle, the Upper Cretaceous and the Tertiary was lower, and the interval may be the target for petroleum exploration in the basin. The velocity field of the Paleozoic and the Neo-proterozoic underlying the Jurassic was very complex as a result of extensive thrust and overlap during the Indosinian movement.
THE GRAVITY AND MAGNETIC DATA PROCESSING AND THE INTEGRATED GRAVITY, MAGNETIC AND SEISMIC INVERSION OF THE HEFEI BASIN
LI Yun-ping, LIU Jin-lian, LIN Zhi-mo, HU Jia-shan, YAN Hong, XIA Jie-zhuang
2002, 24(3): 261-266. doi: 10.11781/sysydz200203261
Abstract:
The Hefei Basin has experinced three regional reconnaissance survey since 1958. In recent years, Shengli oilfield increased investment to the basin and threw in a large amount of funds to carry out seismic and nonseismic exploration, including the high-precision gravity, magnetic and geochemical prospecting covering the whole basin, a 8km×8km 2-D seismic measuring network running through the whole area in length and breadth and eight electrical profiles. In view of the exploration situation of the basin, a wealth of gravity, magnetic and electrical data were used to focus on the target processing of gravity and magnetic data instead of routine processing models.The gravity and magnetic anomaly information and electrical characteristics of regional tectonics, local structures and faults in this area were obtained rapidly and correctly, and the related graphs were drew. This provided reliable, full and accurate bases for the comprehensive hydrocarbon assessment of the Hefei Basin, and resulted in a new set of thinking about gravity and magnetic processing suitable to new area prospecting. Meanwhile, as the Hefei Basin was short of physical property data and rich in geophysical data, a statistical deduction inversion methoel which did not rely upon physical property parameters was proposed. Combined with the 31 seismic traverse data and the gravity and magnetic data of the whole area, a statistical relationship formula was established, the burial depth of the Indosinian discontinuity was calculated by inversion, the integrated gravity, magnetic and seismic inversed Indosinian discontinuity structural mep was drew successfully, and the structural distribution patterns of the areas not involved by the seismic measuring network were depicted in detail. Basides, HF-700 and HF-340 two sections were subjected to integrated gravity, magnetic, electrical and seismic interpretation, and well geological effects were obtained.
CHARACTERISTICS OF THE REGIONAL GEOCHEMICAL FIELD IN THE HEFEI BASIN
SONG Guang-da, CHENG Jun, ZHAO Ke-bin, LI Xue-tian, SUN Chang-qing
2002, 24(3): 267-272. doi: 10.11781/sysydz200203267
Abstract:
The geochemical field of the Hefei Basin belongs to that of low background values, low moisture and inhomogeneity. The concentration of hydrocarbon indexes is high on the periphery of the basin and low in the middle. On the whole, the geochemical anomalies are strong in the east and weak in the west, and zoning in the south and the north. 3-D fluorescence diagrams of the samples within the anomalous zones mainly belong to type B, with type P following it.This corresponds to the characteristics of light oil and coal-formed hydrocarbon. From the geochemical view, the next exploration work was suggested to continuously apply the integrated exploration technology to explain the various kinds of geochemical anomalies on the key areas of Wushanmiao-Shuangdunji, Taoxi-Sanhe and Caoan-Zhuxiang-Bailongzheng.
SEDIMENTARY ENVIRONMENT AND GEOCHEMICAL CHARACTERISTICS OF HYDROCARBON SOURCE ROCKS IN THE CAMBRIAN BASE OF THE HEFEI BASIN
CAO Gao-she, SONG Ming-shui, LIU De-liang, ZHOU Song-xing, LI Xue-tian
2002, 24(3): 273-278. doi: 10.11781/sysydz200203273
Abstract:
More and more attention is being paid to the marine hydrocarbon exploration in the Hefei Basin. The marime argillaceous source rock found in the Lower Cambrian base of the West Hefei Basin has important practical significance, and the stuey on its sedimentary environment and geochemical characteristics is the basis for the further hydrocarbon exploration. Sequence stratigraphical and orgnic geochemical study shows that its sedimentary tectonic environment is at the transitional stage of extensional depressing to shifting spreading, and the basin belongs to the transitional type of internal rift basins to passive continental marginal basins. The is very much advantageous to the formation and preservation of hydrocarbon source rocks. This set of source rocks has the average organic carbon content of 6.46% and I-typed organic matter, and its maturity characterized by Ro(2%-3.5%) and Tmax (500-600℃) reflects its entering into the overmatured early or late stage, The biomarkers reveal that this set of source rocks was formed in the strong-reduction and high-salinity environment, and it originated from bacteria and algae these kinds of low-grade organism, and is in the evolutionary degree of the oil-generating stage. The maturity difference reflected from the two kinds of organic geochemical indexes may result from different organic matter they represent respectively, Ro and Tmax mainly reflect the host rock maturity of source rocks, while biomarkers may mainly reflect the organic matter maturity of rock enclusure. The comprehensive study suggests that this set of source rocks not only is in the peak period of gas generation but also has the potential to form oil. The sedimentary environmental and geochemical research of this set of source rocks provides theoretical basis for the Lower Paleozoic natural gas pool prospecting in the Hefei Basin.
GEOCHEMICAL CHARACTERISTICS OF JINZAI OIL-SOAKED SANDSTONE IN THE HEFEI BASIN
CHEN Jian-ping, JI Guo-sheng, ZHONG Jian-hua, LU Guo-ming, LI Yong
2002, 24(3): 279-283. doi: 10.11781/sysydz200203279
Abstract:
The macropetrology, organic petrology, organic geochemical characteristics and oil source of Jinzai oil-soaked sandstone in the Hefei Basin were studied in this paper. The oil-soaked sandstone, which was discovered in the Middle Jurassic Sanjianpu (J2s) strata of the South Hefei Basin, is an arkose. Oil disseminates along microlayers (laminae) or bedding planes, and organic matter infills pores and fissures taking the shapes of dispersed bitumen or oil drops. Low content of organic carbon (C) and chloroform extracted bitumen "A" is related to hydrocarbon migration as well as the oxidation and biochemism subjected afterwards. The organic mother material, which is dominated by hydrobios and algae, belongs to the sapropel type and is lake deposit under reduction environment. The evolution of organic material has got to the mature stage, and the oil source may comes from the hydrocarbon source rock of the Sanjianpu Formation. So the Shucheng Depression is the favorable zone for the hydrocarbon exploration of teh Hefei Basin.
GEOCHEMICAL CHARACTERISTICS AND SIGNIFICANCE OF THE JURASSIC AND CARBONIFEROUS-PERMIAN MELAMUDSTONE IN WELL AN’CAN-1
XU Shi-hong, WU Guang-hua, HUANG Kai-quan, WANG Guang-li
2002, 24(3): 284-286. doi: 10.11781/sysydz200203284
Abstract:
Organic geochemical characteristics of the Jurassic and Carboniferous-Permian melamudstone in well An'can-1 were studied preliminarily by means of the biomarker analysis technology combined with other geochemical data. The results revealed thet two sets of dark strata have lower organic matter abundance, their organic mother matter is dominated by low-grade hydrobios mixed with high-grade plants, and the type of organic matter is humosapropelic. The high maturity for the thermal evolution of organic matter shows that the hydrocarbon-generating peak has gone, but the strata can still be gas source rock of the area.
2002, 24(3): 287-287. doi: 10.11781/sysydz200203287
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2002, 24(3): 288-288. doi: 10.11781/sysydz200203288
Abstract: