2002 Vol. 24, No. 4

Display Method:
COLLISIONAL STRUCTURES AND BASINAL DEFORMATION IN THE NORTH QAIDAM BASIN
MA Jinlong, LI Fengjun, JIA Qingjun
2002, 24(4): 291-295. doi: 10.11781/sysydz200204291
Abstract:
As a result of the collision of Indian plate and Asian plate during the Oligocene and the Miocene-Pliocene and the continuing squeezing, the thrust sheets of the South Qilan Orogenic Belt advanced to the northern margin of the Qaidam Basin. The Meso-Cenozoic basin in the North Qaidam underwent two generations of deformation. It was characterized by progressive deformation from the imbricate thrust and fault-folded structures in the Saishenteng-Gaqiu Frontal Faulted Zone to the listric thrust fault and fault-folded structures in the Kunteyi Slope Depression Zone, and then to the decollement fault and fold structures in the Eboliang-Yibei area.
STRUCTURAL-DEPOSITIONAL FRAMEWORK AND HYDROCARBON EXPLORATION PROSPECTS IN THE CHAGAN DEPRESSION, THE YINGEN-EJINAQI BASIN
WANG Shenglang, MA Weimin, ZHU Zhixin, SHANG Yazhen
2002, 24(4): 296-300. doi: 10.11781/sysydz200204296
Abstract(1316) PDF-CN(513)
Abstract:
Developed on the the Xing Meng Hercynian Folded Belt, the Yingen-Ejinaqi Basin is a Cretaceous strike slip one with coexisting of rags and highs in the structure. Each sag is characteristic of multiple and near provenance fillings with delta and coastal depositional systems extremely developed, and the latter surely played an important role in the formation of oil and gas reservoirs in this basin. The results illustrated that the Chagan Depression is a most important sedimentary unit lying in the northeast of the basin, and the features of the basin are strong volcano activity, high geothermal gradient (4.8℃/100m) and large sedimentary thickness during the period of rift faulting (K1b-K1s). The diageneses in the target reservoirs (K1b-K1s) occurred early and strongly, which resulted in the low porosity and permeability of reservoir properties (type Ⅳ/Ⅴ). Moreover, due to subjected to reformation and uneven erosion in the forth episode of the Yanshanian event (in the end of K1s), the structural and stratigraphic framework of the primary basin had been changed obviously. Therefore, to resume the proto basin and its distribution and then to seek the syngenetic successive structures principally controlled by paleo-highs should be one of the solutions to looking for the rather good reservoirs and potential petroleum accumulation zones. This favorable reservoir zones are believed to be the controlled by the development of both paleo-highs and depositional systems, while the structural stratigraphic traps will be the main targets for the further exploration.
STUDY ON THE BASEMENT PROPERTIES OF THE SOUTH HAIJIAO UPLIFT IN THE EAST CHINA SEA SHELF BASIN
CHEN Bing, WANG Jialin, WU Jiansheng, ZHONG Huizhi, ZHOU Ping
2002, 24(4): 301-305. doi: 10.11781/sysydz200204301
Abstract:
By gravity and magnetic data processing of the Haijiao Uplift in the East China Sea Shelf Basin and Combined with peripheral gedogic situation and various geophysical information, the basement depth and lithology of the Haijiao Uplift were studied. Based on the inference of basement lithology, the Mesozoic and Paleozoic thickness were obtained. This provides bases for the further development of hydrocarbon resources in the East China Sea Shelf Basin.
DISCUSSION ON THE EXPLORATION OF LOW BURIED-HILLS BETWEEN CHENGDAO AND ZHUANGXI AREAS
CHEN Guangjun, ZHANG Shanwen
2002, 24(4): 306-310. doi: 10.11781/sysydz200204306
Abstract:
The exploration of the Paleozoic buried-hills in Zhuangxi and Chengdao areas has achieved great results. In terms of tectonic evolution, the buried-hills in Zhuangxi and Chengdao once belonged to the same structural zone in geological history. Based on analogy analysis, the low parts between two buried-hills show favorable conditions for hydrocarbon accumulation, which might results in the formation of a united play in the buried-hills. Therefore, the connective parts between Zhuangxi and Chengdao may be a potential area for hydrocarbon explorotion.
STUDY ON THE RESERVOIR-FORMING SYSTEMS OF THE TARIM BASIN
ZHAO Jingzhou, LUO Jihong, SHI Baohong, PANG Wen
2002, 24(4): 311-316. doi: 10.11781/sysydz200204311
Abstract:
The reservoir-forming system (or named the hydrocarbon migration-accumulation system) is defined as a relatively independent system of hydrocarbon migration and accumulation within a petroleum system. The reservoir-forming system is also a natural unit of petroleum exploration and assessment, and its place in a petroliferous basin is just between a petroleum system and a play. The Tarim is a basin with multiple reservoir-forming systems within a petroleum system. In the Manjiaer petroleum system of the craton area, there exists at least three large reservoir-forming systems, i.e., the North Tarim, Central Tarim and West Manjiaer systems. And the North Tarim can be further divided into Lunnan and some other reservoir-forming systems. The Lunnan reservoir-forming system is actually composed of three subsystems, namely, the Ordovicion primary and se condary reservoir-forming subsystem, the Carboniferous overpressure semi closed reservoir-forming subsystem and the Triassic Jurassic secondary reservoir-forming subsystem where most oilfields are the results of oil re migration from the Ordovician and Carboniferous reservoirs along the newly formed normal faults nearby driven by gas intrusion. The Central Tarim includes two reservoir-forming systems named the Central Faulted Belt primary and secondary reservoir-forming system and the North Slope primary reservoir-forming system, and the latter can be subdivided into the Ordovicion and Carboniferous hydrocarbon migration-accumulation subsystems, in each of which vertical and lateral migration and accumulation is predominated respectively. In the Kuche foreland petroleum system, three reservoir-forming systems are distinguished, i.e., the North Kuche Slope normal pressure open system, the Central Thrust Belt normal and over pressure open closed system, and the Luntai normal pressure open reservoir-forming system. And the Central Thrust Belt system can be subdivided into the above Tertiary seal and the under Tertiary seal two subsystems. In the above Tertiary seal subsystem, se condary oil reservoirs are mainly formed; whereas, the under Tertiary seal subsystem is the character of over pressure gas accumulation.
DIVISION OF DEEP PETROLEUM SYSTEMS IN THE DEHUI DEPRESSION, THE SONGLIAO BASIN
GUO Shaobin, LIU Yumei
2002, 24(4): 317-321. doi: 10.11781/sysydz200204317
Abstract:
In recent years, the concept of petroleum systems has got wide attention. It provides a new research method for hydrocarbon exploration. Based on the thermal-evolution profile stuey of organic matter in the hydrocarbon source rock of the Dehui Depression in the Songliao Basin and the thorough collection and collation of drilling, logging, seismic and testing data from the working area, the history of hydrocarbon generation and expulsion was dynamically simulated. According to the laser Raman spectrum analysis of organic inclusions, the correlation of hydrocarbon sources and the abnormal pressure of the strata, the Dehui Depression can preliminarily be divided into two petroleum systems on the deep profile, that is, the lower else-sourced petroleum system which is bounded by the abnormal pressure interface or unconformity plane on the top of the Yingcheng Formation and the upper else-sourced petroleum system which is bounded by the abnormal pressure surface on the top of the Quansan Formation. On the plane, Nongan, Baojia and Buhai three petroleum subsystems were divided. Among them, Nongan petroleum subsystem is the most favorable one, Baojia petroleum subsystem is the second, and Buhai petroleum subsystem takes the third. Otherwise, the lack of the method was pointed out.
ANALYSIS ON THE ENRICHMENT AND ACCUMULATION TYPES OF HYDROCARBON IN THE SOUTHWESTERN SEA AREA OF THE SOUTH CHINA SEA
LIU Baoming, XIA Bin, LIU Zhenhu, WANG Yantang
2002, 24(4): 322-326. doi: 10.11781/sysydz200204322
Abstract:
The study area is located on the collision, underthrusting and accretion parts of plates and landmasses in the southern part of the South China Sea. Based on the stuey of regional geologic structural background and regional stratigraphic correlation, some kinds of traps and five kinds of related reservoirs were classified. Accor ding to the results from basin simulation and petroleum system research, the characteristics, pool-forming factors and exploration prospects of each type of reservoirs were analysed, and the pool-forming times and favorable distribution areas of the reservoir types similar to the oil and gas fields found were pointed out. This will provide scientific bases for hydrocarbon exploration.
THE UPPER PALEOZOIC SEQUENCE STRATIGRAPHIC AND SEDIMENTARY SYSTEM CHARACTERISTICS OF THE SOUTHWEST ORDOS BASIN
ZHU Xiaomin, KANG An, WANG Guiwen, WANG Liqing
2002, 24(4): 327-333. doi: 10.11781/sysydz200204327
Abstract:
Guided by the theories of modern sedimentology and sequence stratigraphy, comprehensively using the outcrop, drilling, logging and seismic data and based on the boundary characteristics of the sequence system domains, the Upper Carboniferous-Permian strata of the study area were divided into three sedimentary sequences. The development information of the lowstand, transgressive and highstand system domains was ascertained, and the characteristics and distribution of seamarsh, river, delta, shore shallow-lake and beach dam these five sedimentary systems were indicated. At last, the favorable developing sequences of source rocks, reservoirs and covers and areas for exploration were suggested.
SPATIAL DISTRIBUTION AND POOL-FORMING RULES OF SANDY-CONGLOMERATIC FANS IN BINNAN OILFIELD, THE BOHAIWAN BASIN
XIE Fengmeng, WU Fadong, CHEN Jianyu, CAO Shuchun
2002, 24(4): 334-338. doi: 10.11781/sysydz200204334
Abstract:
Controlled by boundary faults and the Binxian Uplift, sandy-conglomeratic fans of different geneses such as alluvial fans, fan deltas and turbidite fans were developed in the Lower Tertiary on the northern margin of Binnan oilfield. In this paper, the sedimentary types and corresponding seismic facies of sandy-conglomeratic fans were studied, their sedimentation pattern and seismic recognition pattern were established, and their spatial distribution regularities as well as pool-forming types and rules were summarized. The practice of oil and gas exploration showed that the rules and research methods above are economically effective.
DIAGENETIC CHARACTERISTICS OF RESERVOIR ROCK FOR THE FUSAN MEMBER IN THE NORTHERN SLOPE OF THE QINGTONG DEPRESSION IN THE NORTH JIANGSU BASIN
CHEN Xiaoling, ZHU Jianhui, ZHAO Yongqiang, LI Haihua, ZHU Hongfa, LUO Yuemin
2002, 24(4): 339-344. doi: 10.11781/sysydz200204339
Abstract:
Based on the mould thin section and thin section analysis of cores from the Fusan Member of 24 wells in the northern slope of the Qingtong Depression, the diagenetic characteristics, diagenetic phases and their relationship with the porosity and permeability of reservoir rock were studied. The results indicated that dissolution was the essential favorable diagenesis for the generation of secondary porosity, which was especially well deve loped in the interval of 2 350-2 880 m depth. And compaction and calcitic cementation were the main cause of decreasing porosity. In general, calcitic cementation was more severe in the west than in the east of the study area. In terms of diagenetic stages, there were clear differences in different areas: strong dissolution was occured in Mozhuang area; medium dissolution with strong calcitic cementation in some intervals was developed in Maoshan area; calcitic cementation was common in Yedian-Biancheng area; and South Dainan was characterized by strong compaction. In accordance with the diagenetic characteristics, the reservoirs in the study area were assessed.
DISCUSSION ON THE PORE TYPES OF THE TRIASSIC SANDSTONE IN THE TULUFAN-HAMI BASIN AND THE FORMATION MECHANISM OF SECONDARY PORES
LIU Aiyong, CHEN Gang, LIU Linyu
2002, 24(4): 345-347. doi: 10.11781/sysydz200204345
Abstract:
According to the X ray diffraction, rock thin section, scanning electron microscope, rock physical property and other testing data, the physical property features of reservoirs and the types and formation mechanism of secondary pores for the Triassic sandstone of the Tulufan Hami Basin were discussed and expounded in detail. The comprehensive analyses showed that the Triassic reservoirs of the Tu Ha basin are mainly the Middle Upper Triassic feldspathic litharenite,and the pore types are dominated by secondary pores. As the reservoirs have relatively poor physical properties, they belong to medium porosity and low permeability or low porosity and low permeability resrvoirs on the whole. During the diagenesis of the Triassic sandstone in the Tu Ha Basin, the more favorable fissure solution typed secondary pores were developed, which constitute the major hydrocarbon bearing space types of the Triassic sandstone in the Basin.
SEDIMENTARY MICROFACIES STUDY ON THE SECOND AND THIRD MEMBERS OF THE YAOJIA FORMATION IN HAITUOZI AREA, THE SOUTH SONGLIAO BASIN
YANG Mingda, YANG Minghui, LIU Hongyou, ZHAO Hongtao
2002, 24(4): 348-353. doi: 10.11781/sysydz200204348
Abstract(1026) PDF-CN(457)
Abstract:
Sedimentary facies, sandbody distribution and their control over oil and gas accumulation in the second and third members of the Yaojia Formation in Haituozi area, the Songliao Basin were poorly understood during the process of exploration. In order to solve these problems, the authors deliberately studied sedimentary microfacies, the types of main sandbodies and their distribution in this area by using modern sedimentary and sequence stratigraphy and on the basis of core, logging, seismic and related experimental data. Also, the evolution of sedimentary facies and their control over oil and gas accumulation was summarized, and the pinch out position of sandbeds and advantageous reservior zones were pointed out. All these provided technical supports to looking for blind reservoirs in this area.
ANALYSIS ON THE HETEROGENEITY AND GENESIS OF CRUDE OIL IN THE CLASTIC ROCK RESERVOIRS OF XINZHAN OILFILED, THE SONGLIAO BASIN
ZHANG Zhihuan, WANG Tieguan, CHANG Xiangchun, LI Bohu, ZHOU Yongbing, LIU Guozhi
2002, 24(4): 354-358. doi: 10.11781/sysydz200204354
Abstract:
Some abroad cases showed that the analysis of fluid composition heterogeneity in reservoirs was an important tool to estimate reservoir connectivity. There is obvious heterogeneity of terrestrial clastic reservoirs in the petroleum-bearing basins of China, so that the variety of petroleum composition in reservoirs is more complication and diversification. This paper analyzed the heterogeneity and distribution features of group composition, saturated hydrocarbon components and biomarker composition in the crude oil of reservoirs in Xinzhan oilfield of the Songliao Basin. The geological and/or geochemical factors, such as petroleum sources, oil migration, reservoir rock lithology, geochemical changes of crude oil in reservoirs and reservoir connectivity, which affect heterogeneity and mixed actions of petroleum in reservoirs, had also been discussed. The results showed that the factors affecting fluid composition heterogeneity are very complex, and the reservoir connectivity can not been estimated easily only according to the fluid heterogeneity in reservoirs. It is important to divide oil populations and families and to study various factors affecting petroleum composition before to estimate reservoir connectivity.
STUDY ON THE HOMOGENEITY AND HETEROGENEITY OF CRUDE OIL IN INTER-SALT NON-SANDSTONE RESERVOIRS
PU Xiugang, HAN Dexin, XU Huaixian, ZHAO Houyin
2002, 24(4): 359-363. doi: 10.11781/sysydz200204359
Abstract:
In the exceptional inter-salt non-sandstone reservoirs in the Qianjiang Depression of the Jianghan Basin, source rock is also reservoir rock. In the sequence, the source rock's quality is good, the HC generation ratio is high, and the seal is completed, too; but the reservoir bed's permeability is very low, so the conditions of oil migration are poor. Inter salt crude oil in each reservoir is independent in non fractured areas, but many evidences of oil maturity and biomarks all show that inter-salt crude oil generally has mixture source characteristics. The crude oil in place has always been mixed with mature oil migrated from other areas. This implies that mature crude oil can migrate from generation depressions to high structural areas through low permeability reservoir beds. The homogeneity of inter-salt crude oil obviously reveals that inter-salt crude oil is derived from bacteria and algae in high salinity, high sulfureous and strong reduction environment.
GENETIC IDENTIFICATION METHOD OF KEROGEN-CRACKED GASES AND OIL-CRACKED GASES
CHEN Shijia, FU Xiaowen, MA Lining, CHEN Xinling, ZHANG Xiang
2002, 24(4): 364-366. doi: 10.11781/sysydz200204364
Abstract:
Natural gas is not only originated from kerogen cracking,but also from oil cracking. For type Ⅰ or Ⅱ kerogen,most of natural gas is derived from cracking of oil generated from source rock during oil generation peak, only part of natural gas is originated from kerogen cracking directly. Genetic identification of kerogen and oil-cracked gases is very important for the study of natural gas sources and area exploration evaluation, especially for high maturity areas. Natural gas genesis in the North and Central Tarim was studied according to ln(C2/C3) and (δ13 C213 C3)of gas composition. The results showed that dry gas in the North Tarim is mainly kerogen-cracked gas,and gas in the Central Tarim is mainly oil-cracked one.
STUDY ON THE ORGANIC PETROLOGY OF THE LOWER TERTIARY SOURCE ROCK IN THE JIANGHAN BASIN
MA Anlai, LI Xianqing, BAO Jianping, XIONG Bo
2002, 24(4): 367-371. doi: 10.11781/sysydz200204367
Abstract(1023) PDF-CN(538)
Abstract:
The bulk-rock analysis technology of organic petrology was used in this paper to systematically study the maceral composition, hydrocarbon-generating components and organic thermal-evolution of the Lower Tertiary source rock in the Jianghan Basin. The morphologic maceral content of source rock in the Jianghan Basin is apparently on the low side. On an average, it only takes 1.5 percent of the whole rock volume. Sapropelite is rich in the maceral composition, vitrinite and exinite are relatively developed, and inertinite is poor. The organic matter is dominated by Ⅱ and Ⅰ types. Alginite and mineral bituminous matrix are the main hydrocarbon ge nerating componets of this area. By using vitrinite reflectance and the fluorescence parameters of hydrogen enriched components and non hydrocarbon fractions, the evolutionary characteristics of organic matter in the source rock of the Jianghan Basin were discussed, and the classification scheme of thermal-evolutionary stages for the organic matter was suggested.
KINETIC MODEL OF QUARTZ CEMENTATION AND ITS APPLICATION
YANG Junsheng, MENG Yuanlin, ZHANG Hong, LI Guohui
2002, 24(4): 372-376. doi: 10.11781/sysydz200204372
Abstract:
Quartz cementation is one of the most important diagenetic process. The quartz overgrowth order obtained from observation of thin section often used to determine the diagenetic stage of reservoir rocks. In this article, we established a kinetic model of quartz cementation, in which temperature history, reaction time, detrital mineralogy, grain size and grain coating abundance were all considered. The model can be used to simulate the volume percentage of quartz cementation and the porosity loss during the diagenetic process of siliciclastic reservoir rocks. This has great significance for quantitative study of diagenesis and reservoir description. At last, the kinetic modeling of quartz cementation was successfully applied to the study of reservoirs in Wangjiatun area of Daqing oilfield.
APPLICATION OF THE CURVE-RECOMPOSITION TECHNOLOGY TO THE LATERAL PREDICTION OF RESERVOIRS
XU Zhenglong
2002, 24(4): 377-380. doi: 10.11781/sysydz200204377
Abstract:
Acoustic curves are basic data essential for the wave impedance inversion based on logging restraint. But the acoustic data obtained from practical work usually cannot well reflect the changing rules of subsurface lithology. So, it is needed sometimes to refer other logging information in order to do curve recomposition. Combined with the examples of wave impedance inversion in LMZ area, a curve recomposition method was introduced in this paper, whichincluding curve sifting, data standardization, curve analyses and data recomposition these steps.
FEATURES OF FLOW UNITS AND THEIR GENETIC CLASSIFICATION
LIU Jiyu, WANG Ji, ong
2002, 24(4): 381-384. doi: 10.11781/sysydz200204381
Abstract:
The flow unit is defined as the same reservoir unit with identical seepage features, and it is considered that the flow unit is relative and in some level and scale. After analysing the basic features of flow units, a genetic classification scheme of flow units was suggested. Flow units were classified as seven types controlled by faults, impermeable strata, intercalated bads, permeability rhythm, stratification tectonics, fissures and pore structure, respectively. The flow unit of different genesis reflects the scale and level of reservoir heterogeneity and has different studying contents and methods.