1987 Vol. 9, No. 4

Display Method:
PRINCIPAL FEATURES OF PERMIAN REEF IN LENGWU AREA, ZHEJIANG PROVINCE
Wang Wenyao
1987, 9(4): 299-304. doi: 10.11781/sysydz198704299
Abstract:
The knoll reef in Lengwu Area composes of sponges and belongs to Lengwu Formation,Maokou Stage of Lower Permian.Up to the present,it is the only one reef discovered in the carbonate strata of Lower Yangtze River Area.The thickness of the crop-out reef is over 60 m with the area less than 1 Km2.The reef core lithology is sponge frame-stone and biomicrite.The main frame-building organisms are of sponges and there are diverse attaching organisms.Slip block developed at fore reef while stromatolites developed at back-reef with obviously dolomitization.Both the base and the cap of the reef are attributed to terrigenous elas-tics and most of the facies of strata equivalent to Lengwu Formation in Lower Yangtze River Area changed into terrigenous elastics.The occurrence of the reef is mainly controlled by terrgenous clastics.The various facies belts of the reefs in Lengwu Area are distinct and reflect the possibilities of linear assemblage of the knoll reefs.Therefore,it is hopeful to discover some buried facies reefs in Western Zhejiang.The corresponding locations of the various facies belts for the reefs show the plane configuration of the distribution for land and sea during the period of Early Permian,Maokou stage.It is proved that the Cathaysia did exsit in Maokou Stage and the adjacent seashore line trends northeast.
THE FORMATION, EVOLUTION OF MESO-CENOZOIC BASINS AND THEIR RELATIONSHIP TO OIL/GAS IN LINQING REGION
Long Hanchun
1987, 9(4): 305-313. doi: 10.11781/sysydz198704305
Abstract:
Linqing Region was experienced transformation from platform to Diwa(geodepression)stages during the period from Late Triassic to Early Jurassic.Severe extensions and faultdown took place during Jurassic-Early Cretace-ous and Paleogene,respectively.Thereafter,the two cycles of Mesozoic and Cenozoic Diwa(geodepression)basins and oil formations were formed.In addition to various basin types and complex structural patterns,combined with possible Paleozoic-Triassic platform type oil/gas in this region,it becomes a promising oil/gas prospect area.
CO2 SUPERCRITICAL EXTRACTON AND SEPARATION OF HYDROCARBONS
Li Zhi, Zhu Meiqian, Liu Bing, Mao Hongyi
1987, 9(4): 314-320. doi: 10.11781/sysydz198704314
Abstract:
A series of supercritical extraction experiments on rocks using CO2 were carried out.The result was compared with chloroform extraction.70% of saturated hydrocarbons in rocks could be extracted out in 4 hours,and more than 90% of the extracts composed of saturated hydrocarbons,which could be directly injected into chromatography without the need of precedings.
THE FORAMINIFERA OF QIJIAGOU FOMATION FROM SOUTHERN MARGIN OF JUNGGAR BASIN AND ITS SIGNIFICANCE IN STRATIGRAPHY
Zhu Rong, Lin Jiaxing
1987, 9(4): 321-331. doi: 10.11781/sysydz198704321
Abstract:
There are plenty of foraminiferas(both fusulina and non-fusulina)in Upper Carboniferous Qijiagou Formation from the southern margin of Junggar Basin in Xinjiang Province,and the common ones are Palaeotextularidae Te-trataxidae,Endothridae and Fusulinidae,which can be divided into two assemblages based on the study of non-fusulina foraminifera in this paper.1.The low part of Tolypammina fortis-Palaeospiroplectammina cons-pecta assemblage;2.The upper part of Bradyina coninna-Plectogyra minuta assemblage.The age of the assemblages in the formation may be attributed to early stage of Late Carboniferous and the assemblages can be compared with those of the same stage in other regions both at home and abroad.
THE CHARACTERISTICS AND DIAGENESIS OF PERMIAN REEF ROCKS IN NANPANJIANG AREA AND THEIR RELATIONSHIP TO OIL/GAS POOLS
Zhao Zeheng, Qi Jinwen, Zhang Xiaolin
1987, 9(4): 332-341. doi: 10.11781/sysydz198704332
Abstract:
Based on the geographic location,exposed configuration and the com-plex of the reef body,the reef rocks in Nanpanjiang Area can be divided into three types as platform marginal linear reef,platform marginal horse-shoe reef and patch reef.The principal types of the reef rocks are of framestone,bindstone;reef breccia,etc.The reef-building organisms can be divided into framework-building,binding,binding and attaching organisms on the basis of the different effective to the reef formation.Permian reefs are characterized by reef building up at the time of trans-gression,and dying out at the time of regression,as well as the conti-nuously shifting of a number of reefs.The reefs in this area distribute at the margin and interior of basin facies.As the source rocks were under favourable conditions of hydrocar-bon expelling stage,and valid pore formed at right time by solution,these reefs can be formed as reefoid oil/gas pools(in term of short distant oil trapping).However,since the liquid hydrocarbon restored in such reefs has experienced an over-maturation stage and has been pyrolyzed to be gase-ous hydrocarbon and solid bitumen,the subtle reefoid gas pools can be discovered by the valid exploration activities in the area.
CALIBRATION OF ANALYTIC PARAMETERS FOR PYROLYTIC CHROMATOGRAPHY
Wang Anqiao, Zheng Baoming
1987, 9(4): 342-350. doi: 10.11781/sysydz198704342
Abstract:
The paper mainly deals with calibration of parameters for pyrolytic chromatography.In actual cases,the authors have selected 61 source rock samples of various types to do simulating experiments,and the parameters obtained from the experiments were compiled to draw a calibration plate for S1 and S2.The plate is clear and easy to use,which would be valuable for correct application of pyrolytic parameters.
SURVEY OF THE SUBSTRATE OF TAI—LAKE USING GPY ACOUSTIC METER
Sun Shuncai, Zheng Changsu, Hua Lesun
1987, 9(4): 351-357. doi: 10.11781/sysydz198704351
Abstract:
Acoustic meter of Model GPY is a new remote sensing tool which is developed with special regard to the characteristics of the lakes of China.It would quickly give a general idea about the spacial spreading of the strata under the lake.Using it for three times,we made a survey on the sub-strata of Tai-Lake,with the profile lines over 200km.Preliminary survey reveals that Tai-Lake is a shallow lake with average water depth less than 2m.The substrata,consisting of loessial material,is overlain with recent sediments of several to tens of centimeters in thickness,and underlain by marine sediment of sand and clay interbeds formed during late Pleistocene time(21000-21000 yrs ago).Under the marine sediments,there are brown and grey clays.All the evidences indicate that the alluvial plain extensively covered with loess was prevailing in that time.It was not resulted from a bay and lagoon environment.Over the loessial beds,many river courses and small sags are discovered.Furthermore,many ancient buried hills are also found,suggesting that the basement is not flat.Finally,it is found that shallow natural gas is distributed in near-surface beds of Tai-Lake,which is continuously escaping along errosion valley.
DISCUSSION ON THE STRESS TRAPS OF OIL/GAS
Qi Lin
1987, 9(4): 358-365. doi: 10.11781/sysydz198704358
Abstract:
The main factors of crust deformation are of the changes of stress fields and the geological stress itself.Therefore,the movements of all materials which include oil,gas and water in petroliferous formations and basins are controlled and driven by geological stresses.As the petroliferous formation are considered as elastic-plastic bodies with isotropic,homogeneous and continuous characters,a series of anti-clines and synclines would be analogous to deflection of solid materials which is due to unstable by force.Based on the relationship amound the isopleth distribution of tri-dimensional principal strsses,known oil/gas migration directions and the location of oil/gas accumulation,it is suggested that oil/gas migration direction is perpendicular to the trace of main pres-sure stresses(σ3),and parallel to the trace of main tensile stresses(α1).The oil/gas accumulation is located at low pressure zone in a closed tri-dimensional stress-gradient space composed by the traces of the main tensile stress(σ1)and the central main stress(σ2).
CHARACTERISTICS OF MASS SPECTROGRAM FOR SEVERAL NOVEL STERANE HOMOLOGUES IN SOURCE ROCKS
Yang Jianqiang
1987, 9(4): 366-373. doi: 10.11781/sysydz198704366
Abstract:
Several novel sterane homologues and their isomers were determined,and their mass-spectrographic characteristics are discribed.Here the author believes that the identification of these compounds would be helpful to the researches on the maturity of organic matter in source rock,biodegradation of oil,etc.
SEDIMENTARY CHARATERS OF BRAIDED AND LOW—SINUOSITY STREAMS IN SANDO FORMATION OF LOWER TERTIARY, NORTHERN JIANGSU PROVINCE
Dong Rongxin
1987, 9(4): 374-384. doi: 10.11781/sysydz198704374
Abstract:
In the sediments of paieostreams,there are certain amount of rare mineral deposits,such as gold,diamond,uranium,platinum and monazite,etc.and some important oil/gas reservoirs as well.Therefore,it is practi-cally significant to study the ancient fluvial sediments.Up to the present,much analysis have been made on the sedimentation of the sinuous streams,but those on braided streams are not enough.Taking Lower Tertiary fluvial sedimentation in Sando Formation of Northern Jiangsu as an example,the characters of fluvial sedimentation,and the relation between braided streams and low-sinuosity streams are discus-sed in this paper.For the recognition of the sedimentary characters of such streams,especially of the characters in ancient stratigraphic profiles,the author of this paper establishes a typical profile as a model.
PROGRAMMED COMPUTATION OF GC DATA
Yang Chuanzhong
1987, 9(4): 385-386. doi: 10.11781/sysydz198704385
Abstract:
Using BASIC language,programmed computation of GC data were made.Chromatographic parameters were calculated with PC-1500 programmable mini-computer.The programmed computation can be used to calculate and plot eight chhromatographic parameters for each sample.This method is quick and accurate,providing a useful tool for scientific work and produc-tion.