1997 Vol. 19, No. 1

Display Method:
SEISMIC SPREAD IN WEST KUNLUN AND A-TYPE SUBDUCTION IN SOUTHWEST TARIM
Wu Shimin, Ma Ruishi, Lu Huafu, Jia Chengzao
1997, 19(1): 1-4. doi: 10.11781/sysydz199701001
Abstract:
By studing seismic spread and Cenozoic igneous rocks in West Kunlun, the detection of converted waves and deposit since the Late Quaternary in Southwest Tarim and other characteristics, it is revealed that Tarim continent lithosphere is subducting southwestward beneath West Kunlun in A-type subduction. At last, the forming mechanism of A-type subduction is discussed.
SEQUENCE STRATIGRAPHIC CHARACTERISTICS OF MESOZOIC AND CENOZOIC CONTINENTAL SEDIMENTARY BASINS IN NORTH TARIM BASIN
Zhang Ximing
1997, 19(1): 5-11. doi: 10.11781/sysydz199701005
Abstract(1540) PDF-CN(401)
Abstract:
The sequence development of Mesozoic and Cenozoic cOntinental sedimentary basins in North Tarim Basin has characteristics as follows. Tectonic action controls the development of sedimentary sequences and sequences have obvious cyclicity,the development of sequences has bad completicity because of the effect of tectonic action and the differences of sequence characteristics between the border and the hinterland of the basin are distinct,and the effect of marine transgressive events makes the internal structure of sequences more complex. Based on the characteristics, the framework of sequence stratigraphy is established, 45 seismic and logging sequences are recognized in all, the spread and tectonic characteristics of sequences are described in detail, and the relationship of system domain development to resevoir and mantle combination is analysed.
CHARACTERISTICS AND EVALUATION OF CARBONIFEROUS—JURASSIC HYDROCARBON RESERVOIRS AND MANTLES IN EAST JUNGGAR BASIN
Wang Xu, Yuan Hong, Li Xingping
1997, 19(1): 12-18. doi: 10.11781/sysydz199701012
Abstract:
By means of comprehensive evaluation method, the characteristics of Carboniferous-Jurassic reservoirs and mantles in the North Dengdaohaizi-Wucaiwan Depression and Baijiahai convex slope zone of East Junggar Basin are evaluated. After the combination of the results longitudinally, several sets of reservoir and mantle assemblages are recognized. It is considered that the assemblages of M. U. J1s/L. J1s and U. J1ba/L. J1ba are most important, and the other assemblages are of secondary importance. Based on the distributive features of reservoir and mantle assemblages, the reservoir and mantle assemblages of the study area are predicted and evaluated on-plane.
SEQUENCE FRAMEWORK OF WUCAICHI IN THE EAST JUNGGAR BASIN OF XINJING
Li Xingping, Li Jinglian, Wang Guose
1997, 19(1): 19-24. doi: 10.11781/sysydz199701019
Abstract:
By using the principle of sequence stratigraphy, six supersequences and ten sequences are divided in the study area ,sequence framework from above Carboniferous weathering surface to Jurassic strata is established, and the plane distribution of lowstand,transgressive and highstand system tracts are determined.
MODELLING STUDY ON THE PROFILE STRUCTURE OF TB LINE IN DONGHAI
Xu Xuehui, Jiang Xingge, Wei Wu, Zhang Yuchang
1997, 19(1): 25-33. doi: 10.11781/sysydz199701025
Abstract:
In this paper, 147km of TB seismic profile across Qiantang Depression,Xihu Depression till Diaoyudao upfolded belt is interpreted. In view of the characteristics that Donghai continental shelf basin has gone through fault depression-passive continental margin-compression-depression multistages tectonic superimposition since the Paleocene,the models of depression,prOfile equilibrium and fault depression are established. By means of the modelling software package developed by the authors,the original thickness of eachstage strata is calculated and restored,and the subsiding and compacting processes of depression are reproduced. By the method of the combination of equiarea and critial-layer equilibrium,the recOvery of compressive structure between T40 and T20 is realized,equilibrium profile is obtained,and shorten range of each bedded plane is caIculated. Based on the situation that growth faulting information inverses plow faulting till in the deep part and by calculation on the displacement fields and movement loci of middle and upper plates during the course of extension,the extended range about 10.4km from Xihu Depression to Diaoyudao upfolded belt in the Paleocene period is obtained-By the connexion and combination Of depressiOn,profile equilibrium and fault depression models,the modelling of fault depression-compression-depressio inversion and superimposition is realized, the subducting and developing history of entire tectonics reappears,and the dynamic results of the modellings are shown by the graphs of certain time intervals.
RELATIONSHIP OF COMMUNITY ECOLOGY TO SEQUENCE STRATIGRAPHY IN KAOLISHAN FORMATION NEAR NANJING
Chen Zhongqiang, Shao Guoqiang
1997, 19(1): 34-40. doi: 10.11781/sysydz199701034
Abstract:
In this paper,it is considered that Kaolishan Formation near Nanjing is mainly of marine deposit. Five ecological communities and three sedimentary sequences are recognized altogether. The application of community ecological analysis to sequence stratigraphy is stressed,and the characteristics of Early and Middle Visean sea-level fluctuation in Lower Yangtze area are reconstructed. Compared with the global change of sea level,the eustatic cycle of Lower Yangtze area is somewhat different because of its particularity.
1997, 19(1): 40-40. doi: 10.11781/sysydz199701040
Abstract:
GEOLOGICAL CHARACTERS AND EXPLORATION PROSPECT OF COAL-SEAM GASES IN THE LONGTAN FORMATION OF SOUTH JIANGSU
Xia Nengxin, Li Lina
1997, 19(1): 41-46. doi: 10.11781/sysydz199701041
Abstract:
Based on the geological characters in South Jiangsu area,the geological characters of coal-seam gases in Longtan Formation such as coal-seam characters (thickness, shape, texture, stability, distribution and coal resources), gas content, coal reservoir characters (storage space and rock absorptive characters), degree Of coal metamorphism,gas pressure,hydrogeological conditions etc. have summarized in order to provide geological bases for the present situation and exploration prospect of coal-seam gas resources in the Longtan Formation of the area and obtain knowledge according with Objective reality.
GENESIS OF LOW-PERMEABILITY TIGHT JURASSIC SANDSTONE RESERVOIRS AND POTENTIAL OF DEVELOPING GOOD-QUALITY RESERVOIRS IN HEFEI BASIN
Wang Xin
1997, 19(1): 47-51. doi: 10.11781/sysydz199701047
Abstract:
Jurassic reservoir sand body was widely developed in Hefei Basin, But the porosity and permeability and pore structure of sandstone are all worse.The analysis on available samples reveals that the sand body mainly belongs to low-permeability tight reservoirs, and only the Upper Jurassic has moderate storage quality. In this paper,the genesis of tight Jurassic sandstone reservoirs is discussed in detail by means of section observation, cathodoluminescence test, scaning electron microscope test etc. and comprehensive analyses and investigations. Four types of reservoirs are classified based on their origin. Reservoir potential is varied with different reservoir types. Combined with Organic Geochemistry,Seismic Stratigraphy and so on,the conclusion that the Jurassic strata in Hefei Basin have the potential of developing good-quality sandstone reservoirs is obtained. The directiOn of developing good-quality reservoirs is also pointed out.
FORMING MECHANISM OF CONVENTIONAL CRUDES IN NORTH TARIM BASIN
Chen Zhengfu, Zhai Xiaoguang
1997, 19(1): 52-58. doi: 10.11781/sysydz199701052
Abstract:
There are two genetic types of conventional oils in the northern area of the Tarim Basin. The conventional oils related to the types and maturity of source rocks include continental conventional oils related to Mesozoic moderate-mature source rocks whose source-regions are mainly distributed in Kuqa Depression and whose products are mainly light-conventional oils, marine conventional oils related to Carboniferous mOderate-mature source rocks which have less resource scale and low concentric extent and in which oil and gas fields (pools) have not been discovered so far, and conventional Oils related to Ordovician source rocks in upwelling and slope regions whose middle and upper series though with the low abundance of organic material have widespread distribution and large thickness and whose degraded products are conventional-light oils and the oil-bearing potential of the late stage is worth paying attention to.Conventional oils related to pool-forming stages and epigenetic changes include residual oils formed by epigenetic recreation and conventional oils formed by reassemblage from hydrocarbons pool-fOrmed at early (Hercynian) epoch and conventional oils formed by hydrocarbons pool-formed at middle (Indosinian-Yanshan, latest Middle Himalayan Movements) epoch because of untightly enclosed system in pool-forming periods.Different source rocks, different evolutionary stages and corresponding hydrocarbon products in North Tarim area have gone through the recreation and changes of different stages, times and extent , and formed at last the hydrocarbon pools with different properties, including a large number of conventional oil pools formed by epigenetic recreation.
AN APPROACH TO THE NEW GEOCHEMICAL PARAMETERS OF LIGHT CRUDE AND THE SOURCE ROCKS OF THE TARIM BASIN
Zhou Jinnan, Qian Zhihao, Zhou Guiying
1997, 19(1): 59-65. doi: 10.11781/sysydz199701059
Abstract:
In this paper, a new instrument analytical method for light crude is introduced, that is, the MS analytical method of hydrocarbon types. Hydrocarbon types data for eleven kinds of compounds including alkanes, cyclanes and aromatic hydrocarbons can be obtained rapidly by one sampling analysis. Using this method, the authors analysed 26 oil samples from several different regions in the Tarim Basin, Xingjiang.In order to take full use of the analytical results, a mathematical statistical method is employed to make calculation and analysis of all the results of MS analyses. As a consequence, three new geochemical parameters are suggested for the study of petroleum maturity, the types of oil-bearing mother material and the distance of oil and gas migration, At last, the three new parameters are applied by the authors to discussion on potential source rocks in the Tarim Basin.
A NEW APPROACH TO PREDICTING OIL AND GAS FIELD NUMBERS AND THEIR SIZE AND DISTRIBUTION──A METHOD OF PARETO TRUNCATED DISTRIBUTION MODELLING
Liu Yi, Li Jun, Cheng Xuefu
1997, 19(1): 66-70. doi: 10.11781/sysydz199701066
Abstract:
Based on the methods of origin and statisticaI modelling in hydrocarbon resource assessment, the method of Pareto truncated distribution modelling is constructed to predict oil and gas field numbers and their size and distribution in a mega-petroliferous region. The degree Of resource concentration is also proposed in this paper as an important parameter in resource evaluation, and the modelling procedure is fulfilled through iterative and approximate algorithm. At last, a case application of the oil resource forecasting of Tarim Basin is presented and the selection of related parameters is discussed.
SEDIMENTARY ENVIRONMENTS OF FUYANG OIL RESERVOIR (K1q3+4) IN SONGLIAO BASIN
Lou Zhanghua, Xie Hongsen, Cai Xiyuan, Wang Yuhua, Li Benwu
1997, 19(1): 71-75. doi: 10.11781/sysydz199701071
Abstract:
By studing the lithofacies of coring well sections, lithofacies assemblages and vertical sedimentary sequences , several types of sedimentary environments including sandy braided channels, low sinuosity channels , crevasse splays, interstreams lakes , transgressive deltas , shore shallow lakes etc. can be recOgnized in Fuyang oil reservoirs(K1q3+4).During the sedimentary period of Yangdachengzi oil reservoir, the braided and low sinuosity channels in northern, western and southern sedimentary systems converged in the eastern basin and developed into meandering streams. Along with the sedimentation of Fuyu reservoirs, streams in the western basin began to form lakes. At the late sedimentary stage of Fuyu oil reservoir, lakes quickly extended. Only the sedimentary system in the south developed transgressive delta deposit because of the abundant supplies of sediments. But in other regions, estuarine sandbars were transformed to shore shallow lakes composed of siltstones and thin interbeds.
PHYSICAL BEHAVIOR ANALYSES OF PERMO-CARBONIFEROUS COAL LITHOLOGY AND COAL SEAM GAS RESERVOIRS IN NORTH CHINA
Ning Zhengwei
1997, 19(1): 76-81. doi: 10.11781/sysydz199701076
Abstract:
Based on abundant geological data, the cleat, adsorption, pore volume, gas-bearing property and ash productivity of Permo-Carboniferous coal in North China have been studied systematically in this paper,and the relationship of coal lithology to the physical behavior of coal seam gas reservoirs has been established. It is suggested that coal lithological types with high content vitrinites have better physical behavior conditions for coal seam gas accumulation. The coal beds of Carboniferous and Permian Taiyuan and Shanxi Formations in North China have relatively worse coal lithological types in the North and the South.The central part has the best coal lithological type and is a favourable region for the physical behavior conditions of coal seam gas reservoirs.