石油实验地质

DIAGENETIC TRANSFORMATIOIN OF MONTMORILLONITE AND PRIMARY MIGRATION OF HYDROCARBON, AND OIL-GAS GENERATION

Luo Ruilan, Lu Shue, Zhou Guoqing, Cheng Dayuang

1985, 7(4): 257-267. doi: 10.11781/sysydz198504257

Abstract(508) PDF-CN(305)

Abstract:
With the simulation experiments on diagenetic transformation of mont-morillonite,the primary migration of hydrocarbon is studied. Montmorillo-nite clay specimens are selected from various areas and the simulating experiments are carried out with certain conditions of temperature, pressure and water medium.Also the X-ray diffraction and thermal analyses are made on the clay mineral speciments from some wells in North Jiangsu, Depending on the experiments and analogy analysis, the obvious regularity of diagenetic transformation from shallow to deep is discovered, The main mineral compositions in these wells are expansible montmorillonite at depths of about 2000 m, mixed layer clay of non-expansible illite and montmorillonite at depths of 2500-3800m, and non-expansible illite at depths deeper than 3800 m, In addition, clay of montmorillonite-illite mixed layers are found within the related oil and gas beds, which supports the viewpoint that pore interstitial pressure is created by dehydration during the transformation from montmorillonite to illite.It provides a favourable environment for expulsion of liquid hydrocarbons.

EVOLUTION INDEX--A SIMPLE AND EASY METHOD FOR SIMULATING THE EVOLUTION HISTORY OF KEROGEN

Yang Wenkuan

1985, 7(4): 268-275. doi: 10.11781/sysydz198504268

Abstract(572) PDF-CN(284)

Abstract:
This paper proposes a mathematical model for the simulation of natural thermal degradation of kerogen. Kinetic parameters are determined on the basis of geochemical data of Chinese sedimentary basins. The apparent activation energy E is taken as 15600 cal/mol, and the apparent frequency factor A is taken as 6.7×10⁶/m.y.. When the temperature history of source rocks is established the values of temperature index Ω would be achieved from Table 1. The evolution index S and the residual ratio a of potential carbon in kerogen could be obtained by the following equations: S_i=(Ω_i-Ω_i-1÷Ω_i,I_nα_i=-(S₁+S₂+……+S_i).where n (℃/m.y.) is the ratio of temperatures, and i is the serial number of time intervals. The a value corresponding to the upper limit of principal zone of oil formation is 0.94 and a=0.55 may be used as indicator of the peak of oil generation. As a=0.06, the vitrinite reflectance would be about 2.0%. A lot of Chinese source beds have been simulated, and the results conform to the reality of natural geological sections.

COMPOSITION CHARACTERISTICS OF NATURAL GAS AND THE MECHAMISM OF ITS GENESIS

He Zhigao

1985, 7(4): 276-282. doi: 10.11781/sysydz198504276

Abstract(610) PDF-CN(197)

Abstract:
Based on the thermodynamic theory and combined with the composition characteristics of natural gas, four types and three sub-types of chemical reactions which might form hydrocarbon gases are studied, Thermodynamic analyses of various kinds of reactions are presented systematically, Meanwhile chemical and geochemical methods are used together not only to study the transformation ratio or the condition of the reactions, but also the relative abundance ratio of hydrocarbon compounds, The mathematic relationships among variables are properly treated, Thus, it simplified the complicated chemical and geochemical problems in geological body.

TYPES OF CENO-MESOZOIC PETROLIFEROUS BASINS IN EASTERN CHINA, AND ITS RELATIONSHIP WITH OIL AND GAS--BASED ON THE COMPACTION OF MUDSTONE

Zhang Bopuan, Cui Wulin, Wang Xiuyun, Yan Gao

1985, 7(4): 283-293. doi: 10.11781/sysydz198504283

Abstract(510) PDF-CN(288)

Abstract:
Based on a large number of data of the measured porosity of mudstone, the acoustic logging, and the X-ray diffraction analysis of clay minerials, the types of Ceno-Mesozoic basins, i.e. Sanshui, Miyang, Huanghua, in eastern China, and its relationships with oil and gas are studied. The authors proposed. 1. The compaction curve of mudstone can be used to estimate the denudation and calculate the depths of denudation of a basin or depression. The study shows that the degree of the denudation of the Ceno-Mesozoic basins in eastern China is decreased gradually from south to north. 2. According to the depths of denudation calculated by the compaction curve of mudstone, the Ceno-Mesozoic basins in eastern China can be divided into seriously denuded Sanshui compaction type and slightly denuded Huanghua compaction type. These two types correspond with the two sub-types, from the plate tectonic view point, i. e. the fault-down basin developed on the basis of large-scale of depression fold; and the fault-down basin developed on the basis of large scale of uplift fold, which were formed under extension in eastern China. 3. As to the serious denudation basins,the maximum buried depth of the strata must be restored and the history of oil-generation must be reestabli-shed according to the depth of denudation. 4. In the light of the mixed compaction zone of mudstone and montmori llonite-illite mixed layer zone of clay minerals, the favourable zone of hydrocarbon expulsion of a basin or depression can be defined. Together with the buried history of the basin or depression, the period of the primary migration of oil and gas can then be inferred.

CHARACTERISTIC OF BEACHY UNDERWATER ALLUVIAL FAN FACIES——WITH A PRACTICAL EXAMPLE

Dong Rongxin, Su Meizhen

1985, 7(4): 294-302. doi: 10.11781/sysydz198504294

Abstract(600) PDF-CN(202)

Abstract:
Gaoyou Depression is a dustpan like depression steep in north and gentle in south. The properties of sediments from Dainan Formation in the depression are obviously controlled by paleogeographic environment. The sediments on the northern gentle slope belt of the depression mainly are of delta facies and that on the southarn slope belt mainly of beachy underwater alluvial fan facies. The origin of the beachy underwater alluvial fan facies can be either the transport of terrigenous elastics directly into the lake or the extension of the terrigenous pluvial facies into a lake basin, or may be the both. This paper introduces the lithological properties, the rock texture, and the structure of the beachy underwater alluvial fan facies in details, and presents a profile model as well.

AN APPROACH TO THE COMPREHENSIVE GRADING OF UVCONVENTIONAL RESERVOIR OF QIAN FOYAN FORMATION IN WESTERN PART OF NORTH SICHUAN

Wang Danghi

1985, 7(4): 303-312. doi: 10.11781/sysydz198504303

Abstract(588) PDF-CN(205)

Abstract:
The sandstone of Qianfoyan Formation is tight and poor in micropore-geometry, but commercial oil were found in coarse calcareous shelly quart-zose siltstone. The reason for the storing of oil in Qianfoyan Formation is that the tight sandstone contains multiple layer of unhomogeneous resevoir interlinked by high angular fissures, which control the accumulation and production of oil and gas. Based on the features of the comprehensive logging curves, qualitative discrimination and grading are made.

THE MICROPALEONTOLOGY ASSEMBLAGE OF TAIZHOU FORMATION, NORTHERN JIANGSU DEPRESSION, AND ITS SIGNIFICANCE TO PETROLEUM STRATIGRAPHY

Li Zhe, Zhang Xinan

1985, 7(4): 313-319. doi: 10.11781/sysydz198504313

Abstract(533) PDF-CN(341)

Abstract:
Northern Jiangsu Depression is a fault-down basin of 32,000 km² located in the second uplifted belt of NNE trending-Neocathaysian tectonic system. Sediments have been deposited since Paleozoic, of which the Tertiary is especially important for oil. This paper consists of three parts. l.The sporo-pollen and ostracoda assemblages in Taizhou Formation of the early, middle Paleocene and its time attribution are outlined. 2.In the light of the features of sporo-pollen and ostracoda. assemblages, the palaeoclimate, palaeovegetation and palaeogeography environments of deposition period of Taizhou Formation are discussed. 3.By using the distribution, taphonomy, differentiation, evolution and type characteristics of sporo-pollen and ostracoda fossils, the relationship between the environment of deposition period of Taizhou Formation and the source rock sequences are expounded.

1985, 7(4): 320-323. doi: 10.11781/sysydz198504320

Abstract(508) PDF-CN(256)

Abstract:

AN APPROACH TO COMPUTER IDENTIFICATION OF SPORO-POLLEN

Ghen Minmin

1985, 7(4): 324-329. doi: 10.11781/sysydz198504324

Abstract(758) PDF-CN(261)

Abstract:
As an experimental report, this paper consists of three parts: 1. Numeric coding system for the description of sporo-pollen, 2.Mathematical simulation for identifying the Genus (species) of sporo-pollen. 3.The technique of computer processing for identifying the Genus (species) of sporo-pollen. Finally, an cxamplc of two recent spores is taken to elucidate the creation of a Genus(species)file of sporo-pollen, as well as the idcntificatioa simulation of computer.

AMMONOIDS ASSEMBLAGES OF THE MIDDLE AND LATE JURASSIC FROM NIELAMU COUNTY, TIBET

Huang Yapin

1985, 7(4): 330-339. doi: 10.11781/sysydz198504330

Abstract(508) PDF-CN(232)

Abstract:
The ammonoids described in the paper were collected from the middle and upper Jurassic in Nielamu County of southern Tibet in 1980 and 1981, Stratigraphically, these fossils can be divided into four assemblages and an ammonoids-bearing stratum as follows: 1. Macrocephalous-Indocephalous assemblage located at the basement of Menbu Formation, mainly consists of Macrocephalitidae, 2.Aulacosphinctoibes-Ptychophylloceras lalonglaensis assemblage derives from the middle and upper parts of Menbu Formation with few Katroliceras and Metagravesia genera etc, 3.Virgatosphinctes-Haplophylloceras pinque assemblage from the upper section of Xiumo Formation is characterized by plenty of Virgatosphinctes (sPP.). 4.Berriasella-Blanfordiceras assemblages at the lower part of Gucuo Formation are principally composed of Berriasellidae. Mayaitids-bearing stratum lies at the lower part of Menbu Formation, Based on the correlation analysis among the ammonid faunas and the other faunas from some parts of the world, it is considered the faunas in Tibet present a completed series from Callovian to Tithonian, It is interested that the Tithonian may be divided into three parts with three ammonoids-bearing strata of different features.

1985 Vol. 7, No. 4

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