石油实验地质

BASAL DETACHMENT STRUCTURES AND OIL-GAS TERRITORY IN THE NORTHEAST OF TARIM BASIN

Ding Daogui, Wu Houjiang, Han Zhenhua, Lin Zongman

1990, 12(2): 99-108. doi: 10.11781/sysydz199002099

Abstract(583) PDF-CN(336)

Abstract:
Basal detachment structure is a major structural style of intraplate deformation. At the end of Permian, Tarim plate drifted northward as a result of the opening and closing of Tethy; on the one hand, the closing of Haixi geosycline in Tianshan was advanced; on the other hand, the convergency and pressing after the collision continued, caused the deformation reconstru-ction with basal detachment as the major structural style in Palaeozoic basin of Tarim platform. Tabei (north Tarim) uplift in the northeast of Tarim basin is a nappe uplift belt, being developed on the upper hanging of Yanan ductile shear belt, has a southdipping listric nature. Furthermore, a series of slip fault and decollement structures with southdip bedding plane were formed along the "weak belts" of the Cambrian and Silurian bottom shales in Palaeozoic sedimentary cover.They may be subdivided into interlayer shear fracture cleavage, decollement folds, plastic flow belt, interlayer slip band and fault-slip front pressing belt. In the Palaeozoic strata in Tarim basin, there are the decollement folds of detachment faults, the dragging anticline on the upper hanging, and the relict on palaeo-erosion surface caused by late movement.They are the domi-nant structures for oil-gas accumulation in the study area.

ON PALAEOGENE SEISMIC STRATIGRAPHY IN LANGGU DEPRESSION

Zhu Xiaomin, Guan Shourui, Fang Tanshu

1990, 12(2): 109-120. doi: 10.11781/sysydz199002109

Abstract(764) PDF-CN(294)

Abstract:
Firstly, five major types and distribution patterns for seismic and sedimentary facies o Palaeogene in Langgu depression were analysed with the basis of geology, logging, seismic informations. Next, the authors described the characteristics of each facies type of seismics and sedimentation,and suggested the lateral distribution of the seismic facies and sedimentary facies is of asymmetric and vertical evolution with a succession and difference. Finally, areas favourable for petroleum exploration are predicted.

ON SEDIMENTARY CHARACTERISTICS AND TECTONIC ENVIRONMENT FOR THE BASINS OF EARLY PALAEOZOIC IN ZHE-WAN-GAN-MIN REGIONS (PROVINCES OF ZHEJIANG-ANHUI-JIANGXI-FUJIAN)

Zhu Hongfa, Zhang Yuchang, Qin Deyu, Zhou Haoda

1990, 12(2): 121-134. doi: 10.11781/sysydz199002121

Abstract(586) PDF-CN(352)

Abstract:
With the view of the characteristics and distribution of sedimentary facies, the original environments for iso-sedimented rocks,deep-water distant-sourced turbidites in Cambrian of Gannan (South Jiangxi) and Minbei (North Fujian) and shallow water near-sourced turbidites in the upper Ordovician in Zhexi (west Zhejiang) were mainly analysed and the schema of lithofacies distribution for each period (series) of the early Palaeozoic were drafted. The authors proposed that regional northwestward piece together and connecting-pressing begun at the end of the middle Ordovician caused a uplift in South China (including Fujian and Zhejiang), and a seesaw-typed reverse of the structure-sedimentation framework in the study area, where there had been a platform from northwest to southeast or a southeastward palaeo-passive continental margin during the Sinian-middle Ordovician, which were transformed into another structural-sedimentary framework of an intraplate basin with its center in the northwest and it was gradually drifted toward northwest from the late Ordovician to Silurian.

A GEOCHEMICAL DETERMINATION OF THE SUBDUCTION OCEAN CRUST IN EAST QINLING MOUNTAINS

Gao Changlin, Qin Deyu, Ji Rangshou, Yin Yong

1990, 12(2): 135-146. doi: 10.11781/sysydz199002135

Abstract(567) PDF-CN(382)

Abstract:
The relic of subduction palaeooceanic crust is recognized in Song Shugou area of Shangnan in the eastern Qinling with the geochemical methods proposed by the authors. The existence of ophiolite suite and volcanic rock zone is the reliable evidence for the determination of subduction palaeooceanic crust. Ultrabasic rocks, which are pure olivinfels and orthorhomic pyroxene in Song Shugou ophiolite suite, are geochemically characterized by rare earth elements of loss mantle rocks. The basic (metamorphic) lava mixed in the ophiolite suite is practically a oceanic tholeiites and they have some characteristics such as less SiO₂ (52%), high TiO₂ (0.80%), high ratios of TiO₂ /SiO₂, high Q value, low K value, low REE value, low ratios of ΣCe/ΣY and poor in light rare earth elements, these and tholeiites are resemble to oceanic basalts. The volcanic rocks of Danfeng group adjacent to the ophiolite suite are calc-alkali island arc-typed rocks with low ratio of TiO₂/SiO₂, low Q value, and high values of K, ΣREE, and ΣCe/ΣY, enriched with light rare earthelements, which are similar to the volcanic rocks of island arc type. Based on the data mentioned above and the results of correlation analysis of common elements, the authors suggested that the volcanic rocks of Danfeng group were formed in island arc environment, while the volcanic rocks in Song Shugou area were formed in oceanic environment.

A SIMULATION EXPERIMENT OF PETROLEUM ORIGIN ON KEROGEN FROM SHALES OF THE LOWER XIAMALIN FORMATION IN THE UPPER PROTEROZOIC

Liu Baoquan, Cai Bing, Fang Jie

1990, 12(2): 147-161. doi: 10.11781/sysydz199002147

Abstract(780) PDF-CN(500)

Abstract:
A simulation experiment was made on kerogen from shales in the lower Xiamalin Formation of the Proterozoic in North China.Certain characteristics and the law of the thermal evolution for the organics from the lower Xiamalin Formation have been revealed in the study.Furthermore, with the basis of experimental results, an evolution model of oil and gas generation for the middle and upper Proterozoic is developed, and the limit of maturity index is marked, which provide the evidences for the determination of organic maturity and the assessment of petroleum resources.

QUALITATIVE EXPERIMENTS ON THIOPHENE COMPOUNDS IN MINERAL FUELS

Wang Peirong, Tan Junxiong, Bao Jianping, Zhao Hong, Dai Yunjian, Zhu Cuishan

1990, 12(2): 162-177. doi: 10.11781/sysydz199002162

Abstract(1283) PDF-CN(238)

Abstract:
The study mainly deals with a systematic qualitative analysis of the thi-ophene compounds in mineral fuels.During the experiments, we obtained the characteristics of GC/MS, reserved the exponential value and distributive pattern.The experiments provide certain basis for detailed geochemical study.

A QUICK PREDICTION OF THERMAL EVOLUTION FOR ORGANICS IN BAYANHUA GROUP OF ERLIAN BASIN WITH THE APPLICATION OF GEOTHERMAL LOGGING DATA

Zhang Wenlong

1990, 12(2): 178-181. doi: 10.11781/sysydz199002178

Abstract(474) PDF-CN(248)

Abstract:
Using the methods of mathematical geology, a criminant function is devel-oped for the thermal evolution of organics from Bayanhua group, based on geothermal logging data. Before the estimation of petroleum generation, a direct statistic prediction for the thermal evolution of organics can be made on the basis of statistical correlation of geothermal loggings and the thermal evolution of organics. The results of the prediction are fundamentally consistent with those from the estimation of petrolenm generation.

APPROACH ON INFORMATION FUNCTIONS AND CONODONT PALAEOCOLOGY

Wang Ande, Wang Hengding

1990, 12(2): 182-190. doi: 10.11781/sysydz199002182

Abstract(673) PDF-CN(245)

Abstract:
The strata in the adjacent area of Su-Zhe-Wan (the provinces of Jiangsu, Zhejang, and Anhui) area dated from Changxing period of the late Permian are taken as a rock unit, which, from southeast to northwest of the study area, are successively divided into peri-beach tide-flat fades, shallow water carbonate platform facies, platform-front carbonate depression fades and peri-platform margin siliceous rock facies. The yields of conodonts from the sections of different facies belts are studied, and the data are processed on computer with the method of information functions. It has been found that the yield frequency,differential index,yields,isostatics, the species and forms of conodonts from different facies belts are all closely related to sedimentary facies, paragenetic minerals, water depthes,salinity and hydrodynamic conditions. The synthetical study shows that 1. the environments favourable for the breeding and living of conodont animals are shallow-water carbonate platform facies and platform front depression facies, especially the latter; 2. peri-beach tide flat facies with shallow water body and peri-platform margin siliceous rock basin facies with deeper water body are unfavourable for the living of conodont animals; 3.the extensively distributed monomolecular organs belong to the plankton ecological type of Neogondodella, while the limitedly distributed polymolecular organs belong to the benthic ecological type of Prioniodella, Hibbardella, and Enantiognathus.

ANALYSIS AND APPLICATION OF CONCAVE PRESSURE-RESTORING CURVES FOR OIL WELL

Feng Wenguang

1990, 12(2): 191-199. doi: 10.11781/sysydz199002191

Abstract(919) PDF-CN(288)

Abstract:
A basic formula for concave pressure-restoring curve and two methods of linear analysis are proposed, applying the theory of non-Darcy low speed seepage flow. The results from the two analytical methods are entirely consistent, and several reservoir parameters, i.e the primary stratigraphic essure, permeability, initial pressure gradients and flow coeficient, can be obtained by using the two methods in the analysis of concave pressure-restoring curve. They are simple and convenient.

1990, 12(2): 200-200. doi: 10.11781/sysydz199002200

Abstract(502) PDF-CN(234)

Abstract:

STUDY OF THE INFLUENCE OF MINERALS ON PYROLYSIS

Gao Xianzhi, Zhang Wanxuan, Zhang Houfu

1990, 12(2): 201-205. doi: 10.11781/sysydz199002201

Abstract(577) PDF-CN(357)

Abstract:
8 kinds of minerals common in sedimentary rocks are selected, which are mixed with organics (kerogen) to make pyrolytical experiments, so as to study the influence of minerals on organic pyrolysis. The experiments revealed that of the eight kinds of minerals, quartz, orthoclase, calcites and dolomites have basically no influence on pyrolysis; while kaolinites, illites and montmorillonites appeared to have much influence upon the characteristics of pyrolytic-chromatography, which in comparing with the characteristics of pyrolytic-chromatography from pure kerogen (without adding any minerals), following changes are recognized. 1. rapid decrease in alkene, 2. decrease in macromolecular alkane, 3. increase in small-molecular alkylbenzen, 4. increase in volatile components.

COLOUR ALTERATION OF FOSSIL POLYPODIISPORITES AND MATURATION OF THE ORGANIC MATTER OF JINGGU BASIN

Li Yuanmei, Xia Kaihua

1990, 12(2): 206-212. doi: 10.11781/sysydz199002206

Abstract(622) PDF-CN(230)

Abstract:
The relationship between colours of fossil Polypodiisporites,a widespread fossil spore in Cenozoic of Yunnan, and the maturation of organic matter could be employed to infer the stages of petroleum generation and evolution, and to indicate the favourable horizons and areas for petroleum prospecting. The study indicates that the colour of Polypodiisporites can be darker one grade over that of other sporo-pollen within the same rock specimen, though they all were subjected to the same palaeotemperature.For the Tertiary of the Jinggu Basin, the relationship between the colour of Polypodiisporites and the organic matter maturity is as follows. For yellow-orange section, the colour index ranging from 2.6-3.0, corresponding to vitrinite reflectance 0.42% and palaeotemperature of less than 60℃, indicates an immature stage of organic matter. The brown-black section, colour index 3.5-5.9, reflectance 0.58-0.8%, palaeotemperature 60-110℃, indicates the mature stage with the greatest potential of oil-generation. The effects of the amount of organic matter on the colour of sporo-pollen have also been discussed in the paper.

1990 Vol. 12, No. 2

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