1997 Vol. 19, No. 3

Display Method:
THE CHIMNEY EFFECTS OF HYDROCARBON ACTIVITY
Wang Jinqi
1997, 19(3): 193-200. doi: 10.11781/sysydz199703193
Abstract:
When a deep-seated hydrocarbon accumulation had formed in a structurally active area,the hydrocarbons will migrate vertically up through a fault or a fracture,the major part of which was apt to lose to the surface,but the minor part was cut off by the caprocks to form into various shallower secondary oil/gas pools with their specific oil-gas laws.The study highlights pool-forming mechanisms related to chimney effects such as the basis of hydrocarbon source,conduits and power,the impedance type of cutoff process,the compactness of rocks etc;and mainly approaches to the geological conditions for the oil/gas fields of secondary enrichment.
A STUDY ON THE HETEROGENEITY OF SAND BODY RESERVOIRS IN TRIASSIC BRAIDED DELTA, NORTHERN TARIM BASIN──EXEMPLIFIED BY AKEKULE──DALIYA REGION
Zhang Ximing, Wang Shuyi
1997, 19(3): 201-208. doi: 10.11781/sysydz199703201
Abstract:
The Sand body of Triassic braided delta in northwest Tarim basin is one of the major hosting reservoirs of oil/gas pools in this area,which can be divided into a frontal subfacies and plain subfacies according to their depositional features.Based on the analogy of typical sections in field and detailed analyses of drilling cores,six classes of bounding surface and nine architectural units are identified for the sand body of braided delta in Akekule——Daliya region.Furthermore,in view of the features and scale,the hetero-geneity can be classified into four classes,whieh will control the enrichment of oil/gas to different extents,resulting in a petroliferous difference in the sedimentary reservoir bodies either vertically,laterally or upwards.
CONTROLLING FACTORS OF THE DISTRIBUTION OF CONVENTIONAL CRUDES IN NORTHERN TARIM BASIN
Zhai Xiaoxian, Chen Zhengfu
1997, 19(3): 209-214. doi: 10.11781/sysydz199703209
Abstract:
Based on the characteristics of oil/gas occurrence and its genetic mechanism,the paper detailed the controlling factors of the distribution of conventional crudes.It is suggested that conventional crudes are mainly controlled by the following factors,including time of pool-formation,oil/gas source area,conditions of migration and accumulation,and conditions of preservation and structure.Their combined function and affects will determine the regional distribution of conventional cruddes.Of these controlling factors,the thermal evolution of source rocks in source area and the conditions in pool-formation and later preservation are most important.
GEOCHEMICAL CHARACTERISTICS ANE GENETIC ANALYSIS OF CO2 FIELDS(POOLS) IN EAST CHINA
Li Xianqi, Dai Jinxing
1997, 19(3): 215-221. doi: 10.11781/sysydz199703215
Abstract:
Numerous CO2 fields(pools) of inorganic origin are discovered in east China.Usually their CO2 contents exceed 6O%,and alkane gas contents are lower than 1O%.After an analysis of geochemical parameter s i.e.carbon isotopic composition and R/Ra value of CO2,etc,plus a combination of the geological features of the related pools,the paper proposed that except those in Yingge marine basin,which have a metamorphic origin,the rest of CO2 fields (pools) in east China can be attributed to predominantly an origin of mantle-derived volcano-magma.
MANIFESTATION OF MULTISTAGE EPISODIC RIFTING──TAKE WESTERN PEARL RIVER MOUTH BASIN AND ITS PERIPHERAL AREA AS AN EXAMPLE
Jiao Yangquan, Li Sitian, Xie Xinong, Ren Jianye
1997, 19(3): 222-227. doi: 10.11781/sysydz199703222
Abstract:
Multistage episodic rifting refers to episodic and pulsed processes of tectonics occurred during a rift basin evolution.And its process usually matched the deformation of tectonic framework,the episodes of tectonic subsidence,magmatism and sedimentary filling in a rift basin,which were actually the responses to the tectonism,magmatism and sedimentation taken place during the multistage episodic rifting,thereby,they can provide some tectonic information.The tectonic framework deformation,tectonic subsidence and sedimentary filling were almost synchronous with the development of rifting;magmatism often occurred between two rifting episodes.Thus a study of the records on the western Pearl River Mouth basin is helpful for revealing the evolution history of rift basins.
AN APPROACH TO THE DIAGENESIS OF RESERVOIR SANDSTONES FROM JURASSIC-CRETACEOUS IN JIANGSU REGION
Lu Hong
1997, 19(3): 228-233. doi: 10.11781/sysydz199703228
Abstract:
With numerous observations on thin sections of rocks and core casts from drillings,and the application of various analytical techniques including cathodoluminescence,scanning electron microscope and X ray diffraction,the paper made a detailed study on the diagenesis,pore evolution and the characteristics of diagenetic sequence in Jurassic-Cretaceous reservoir sandstones,northern Jiangsu.It is concluded that the behavoir of the major Mesozoic terrestrial reservoir sandstones in Jiangsu is both controlled by depositional conditions and affected by burial diagenesis.Compaction,cementation and replacement and dissolution are most influential factors that control over the evolution of porosity,among which cementation and dissolution are of importance that will affect the formation of reservoir space directly.
1997, 19(3): 233-233. doi: 10.11781/sysydz199703233
Abstract:
DISTRIBUTIVE CHARACTERS OF HYDROCARBONS IN WAN’AN BASIN, SOUTHWEST CHINA SEA
Jin Qinghuan, Liu Baoming
1997, 19(3): 234-239. doi: 10.11781/sysydz199703234
Abstract:
The authors analysed the regional geology,sedimentation,and the geologic conditions of petroleum,and their relationships with the evolution of hydrocarbon source rocks,based on the data collection from the petroleum exploration and seismic survey of Wan'an Basin,southwest China Sea,over the recent decades.As a result,the distributive characters of oil/gas resources in the basin are concluded,which will provide bases for further oil/gas exploration.
DECISION ANALYSIS OF THE EXPLORATION OF KUIHUADAO STRUCTURE IN EAST DEPRESSION, LIAOHE BASIN
Xu Xianghua, Li Shusen, Li Yuzhan
1997, 19(3): 240-244. doi: 10.11781/sysydz199703240
Abstract:
The exploratory decision analyses based on a prediction of the petroliferousness in traps,the study of the performance parameters in the process of oil/gas discovery involved in different exploration programmes and finally to make a most satisfactory choice among various exploration programmes,constitute an important premise for a reasonable strategic deployment of exploration.With the decision analyses relat-ing to trap and regional exploration,the priority traps and blocks in Kuihuadao structure are selected for further exploration.
GEOSTATISTICS APPLIED TO THE IDENTIFICATION OF INTERBEDS, WITH SHA-3 MEMBER OF WESTERN LIAOHE DEPRESSION TAKEN AS AN EXAMPLE
Lin Chengyan, Hou Lianhua, Dong Chunmei, Zhang Jie
1997, 19(3): 245-251. doi: 10.11781/sysydz199703245
Abstract:
Taking Sha-3 member of western Liaohe depression as an example,on the basis of characteristics of time and spatial distributions for the reservoirs,insulating and interbeds in the turbidite sedimentary system,the conditional stochastic simulation method of geostatistics is applied to predict the space distribution of insulating and interbeds.Furthermore,three different types of interbeds are identified with the application of fractals.
SEQUENCE STRATIGRAPHY ON NEOPROTEROZOIC OUTCROPS, IN NORTHWEST HUNAN, SOUTH CHINA
Yin Yong, Fan Xiaolin, Gao Changlin, Zhang Linghua
1997, 19(3): 252-260. doi: 10.11781/sysydz199703252
Abstract:
The Neoproterozoic successions in northwest Hunan,South China belong to a stable sedimentary region of paleo-continental margin along the southeast border of Yangtze platform.The paper deals with the sequence stratigraphy on Neoproterozoic (1000-57OMa) outcrops in the area.Adopting a dividing plan of gallery-typed section and comprehensive sequence stratigraphy,14 Ⅲ order sequences are divided from Neoproterozoic successions in the stable shallow marine area,based on careful field investigations on outcrops,i.e.4 sequences in Laoshanya Formation (equal to Banxi Group);2 in Dieshuihe Formation (equal to Liantuo Formation);1 in Dongshanfeng (equal to Jiangkou Formation)——Xiangmeng Formations;1 in Nantuo Formation;2 in Doushantuo Formation and 4 in Dengying Formation.Altogether 7 type-I sequence boundaries and 7 type-II sequence boundaries and 1 immersed uncomformity are identified on outcrops.By a orrelation of sequence stratigraphy over the whole area (including Dongkou area in central Hunan),a Sinian (800-570Ma) synchronous stratigraphic framework is established in norhtwest Hunan.It is concluded that a synthetic approach suitable to the Neoproterozoic sequence stratigraphy on outcrops across the area should be adopted.And further the paper ptosposed new concepts about the location of stratigraphy,lithofacies-paleogeography and the evolution of paleo-tectonics.
APPLICATION OF SEISMIC VELOCITY TO THE EXPLORATION OF SHALLOW GAS
He Li, Liu Meiqing, Yu Xiaofeng
1997, 19(3): 261-266. doi: 10.11781/sysydz199703261
Abstract:
Commercial oil/gas reservoir determined by the well drilling and seismic channels across the well are used to prepare combined records which are plotted on the seismic profile;then using a recursion formula for the seismic velocity spectrum and interval velocity,the velocity values having the same time domain with the oil/gas geologic body are picked up and calculated.Based on the method of superposition of differential velocity proposed by Leder,an American scholar,the superposition of velocity values from the top and bottom of the geological body are made.The results show that the abnormal sounding zone with a low velocity would be a gas reservoir.The method is applied to a trial study in Xinchang gas field after a delineation in plane by means of tracing and closing in the seismic net;it is found that the gas pool of Penglai Zheng Formation,and gas reservoirs A&B of Shaximiao Formation from the upper Jurassic above 1600-2200m indicate a higher rate of coincidence with low velocity abnormaly,as high as 80%.Gas reservoir C of Shaximiao Formation of middle Jurassic below 2200m indicate a lower rate of coincidence,about 2O%-30%.
PLOTTING OF SEDIMENTARY MICROFACIES IN FIFTH-CLASS BOUNDARY SURFACE SEQUENCE, ITS SIGNIFICANCE AND PRACTICE IN OIL FIELDS
Ma Lixiang
1997, 19(3): 267-273. doi: 10.11781/sysydz199703267
Abstract:
Three advances on the contemporary petroleum geology are remarkable,i.e.sequence stratigraphy,3-D reservoir architecture and oil /gas detection.The paper reviews the significance and practicable way of plotting with sedimentary microfacies in fifth-class boundary surface sequence in a oilfield scale.Lastly it briefs the practical process,taking XLH Oil Field in east China as an example.
STUDY OF ANAEROBIC BIO-DEGRADATION OF COAL
Li Mingzhai, Zhang Hongnian, Zhang Hui Deng, Yu Lian Liwen, Yin Xiaobo
1997, 19(3): 274-277. doi: 10.11781/sysydz199703274
Abstract:
Over a long period of time,whether coal can be degradated by anaerobic microorganism into gas,has been a controversy concerning geology,method and technique in geoscience.The paper deals with this subject based on the simulation experiments on biogas.It is proved that coal can be degraded by anaerobic microorganisms.Furthermore the paper discusses the significance of gas derived from the anaerobic degradation of coal for the selection of prospect areas of coal bed gas.
A PRELIMINARY APPROACH TO THE SET-UP OF A DATA BASE
Zhang Zukui, Liu Bin
1997, 19(3): 278-282. doi: 10.11781/sysydz199703278
Abstract:
Three basic processes are required to set up a practical application system,i.e.the designings of concept structure,normalized structure and programs.They usually take concerted actions,and condition and complement each other.The paper described the preparation of the code standard file,the designing of translator software of paleobiology,and the designing of visual interface for sedimentary rocks,as well as the set-up of special field and the application of 4GL language,which are involved in a set-up of data base.
CHARACTERISTICS OF HYDROPYROLYSIS OF PALAEOZOIC IMMATURE ALGAL KEROGEN
Gao Gang, Gang Wenzhe, Wang Feiyu, Hao Shisheng
1997, 19(3): 283-288. doi: 10.11781/sysydz199703283
Abstract:
Through a study of hydropyrolytic process on oil shale samples colleced from Kukesait,Estonia,the characteristics of oil/gas generation from immature algal kerogen are approached in this paper.It is concluded that although it does show a quite high potential of hydrocarbon generation as seen by an analysis of thermal simulation experiments,the amount of immature oil yielded by algal kerogen is rather low.Its hy-dropyrolysis can well reproduce the process and characteristics of oil/gas evolution,indicating that it is difficult to form algal kerogen-derived oil/gas pools on a considerable scale.With a wider range of liquid window,in the mature stage,algal kerogen tends to generate oil rather than gas;moreover,the generated gas will be dominated by nonhydrocarbons.In the higher mature stage,a large quantity of light hydrocarbons and condensates is generated by the cracking of oil;and the early stage is characteristic of less gaseous hydrocarbons generated,while in the late stage,they would increase.The gaseous products are dominated by CO2,and the content of methane is the highest among gaseous hydrocarbons,containing only a little amount of alkenes.The normal-isohydrocarbon composition is comprised of a very high content of nalkanes but less isohydrocarbons.Pyrolytic oil is predominating over the liquid products,with the peak oil generation around 300℃.The simulation time would affect the hydropyrolysis to certain extent,and a prolonged time would favourable for oil-cracking and increasing gaseous hydrocarbons.
ON THE SEPARATION OF ORGANIC MACERAL DURING THERMAL SIMULATION OF HYDROCARBONS FROM COAL
Tu Jianqi, Jin Kuili
1997, 19(3): 289-291. doi: 10.11781/sysydz199703289
Abstract:
In view of the demand from thermal simulations from coal,the paper detailed the method and process of the centrifugal separation of organic mono-maceral by using ZY-1 inorganic heavy liquid.Three steps are involved with the process of separation and enrichment:selection of grain size for sample crushing,conditional test and preparative enrichment.Several samples are separated and enriched,and the highly pure maceral derived from the process above can meet the demands for thermal simulation.Additionally the density areas of different organic macerals are located.
TECHNIQUE OF MICROBIOLOGICAL PETROLEUM EXPLORATION AND ITS RESULTS OF APPLICATION IN EAST CHINA SEA
Zhang Jianpei, Shen Zurong, Wang Fei, Xi Minhong
1997, 19(3): 292-295. doi: 10.11781/sysydz199703292
Abstract:
The technique of petroleum exploration based on microbiology is illustrated in this paper,which is applied to actual petroleum geochemical exploration in the known and unknown areas in Xihu sag,east China Sen.The anomaly of hydrocarbon-digesting bacteria in sediments can effectively indicate and predict the potential information underground.The results from the oil/gas prediction by microbiology are consistent with geological,geophysical,and drilling data available,which suggests a promising application.