The author reviewed the background and the course of the Sixth Five Year State Key Technologies R and D Programme, introduced the scientific achievements of coal formed gas study, and emphasized the main significance of the R and D study to the gas industries in China.
Zhongyuan oil field is located in Dongpu depression in which crude oil and gas is enriched. After exploration and exploitation for more than two decades,it has become a important oil and gas production base in east China. In this paper the author reviewed Zhongyuan oil field Three Years Science Research, State Keystone Project of Coal gas and Natural gas during the "Sixth Five Year Project" and "Seventh Five Year Project" period. And its contributions to the exploration and exploitation of Zhongyuan oil fiel...
The gas exploration obtained certain reserves volume in spite of going through a rough and bumpy road in Yingqiong basin. Because there are great difficulty of exploration and unknown gas exploration trend, it is a state of seeking. Geologic condition of gas accumulation being researched, the author holds that we start with hydrocarbon source rock of gas pool form and exploration of coal-related gas, so as to obtain great breakthrough, expand gas reserves volume further in Yingqiong basin.
Author’s experience in taking part in the state key projects for natural gas in last 16 years has been reviewed. The research results of the author’s group are also summarized, which is including the assessment and identification of source rock for natural gas. It shows that the implementation of the state key projects for natural gas is a good opportunity for young people to join scientific research and make contribution to the country. The paper is in memory of the 20th anniversary of the implementation.
In the transition zone from the plat to the geosyncline in the west of Ordos Basin, because of the development of Paleozoic arcuate rift system, the land mass was deformed into arcuate structure zone with structural blocks north and south, structural zones east and west, swells and sags. And the distribution and accumulation of oil and gas was controlled by the arcuate structure zone. And the zone, which experienced the later transformation and coupling and deformation, is an important exploration region.
The Wushi-Wensu area is an important transfer zone of the southern Tianshan foreland thrust belt, and has large oil and gas resources. Using outcrop, remote satellite pictures, seismic profiles and gravity data, we built a structural model of this area, restored it’s evolutionary history, and further discussed it’s gas and oil formation process. The results show that the structural style transforms laterally, and the area is comprised of two units. The northern part, Wushi sag, is a contractive fault.
Recognizing Songliao basin from tectonic system in a big scale, is helpful to scan and newly evaluate the rule of oil-gas storage. This paper synthetically analyzes tectonic systems and their dynamics background as follows: Neimeng-Xing′ an structure system and west-Pacific structure system, regional latitudinal structure and regional longitudinal structure, and NWW-NNE conjugated fracture structure.
Sichuan basin is a rich gas basin which has plentiful hydrocarbon source rock and reservoir, being undergone two processes of cratonic basin and foreland basin. According to the structural evolution of Sichuan Basin, the combination of reservoir and cap rock may be divided into cratonic up-strata, cratonic down-strata and foreland strata. Although Natural gas is distributed in three stratas, most is distributed in cratonic up-strata and foreland strata. Gas concentration in cratonic down-strata is controlled.
There is the commercial exploration perspective of lithologic biogas pool in the Sanhu depression of the Chaidamu basin, NW, China. The multicyclic tectonic movement, multiperiodic raising and falling of lake watertable have provided the basis of materials for the forming of each kind of lithologic gas pool. Biogaseous generation has supplied plentiful gaseous source for a long time. The larger-area distribution of sandstone layers with good porosity has provided the migratory concentration condition.
There is large natural gas resource in Junggar basin, however, the gas exploration is still at the early phase. 15.12% of the discovered rate and 3.48% of the proved rate indicates the Junggar basin has good potential for gas exploration. It is proved that the main source rocks of Junggar basin include Jiamuhe formation, Fencheng formation in lower Permian, Wuerhe formation, Lucaogou formation in upper Permian, Badaowan formation in lower Jurassic, and Xishanyao formation in middle Jurassic.
The component of natural gases of Panyu low uplift in Pear River Mouth Basin exists obvious difference, including pure hydrocarbon gas reservoirs, inorganic formed CO -2 gas reservoirs and high N~2 content gas reservoirs. The carbon isotope value of ethane of most natural gases is less than -28‰, belonging to mixed gas and oil-type gas. The carbon isotope value of methane is between -44.2‰~ -33.6‰ , C~ 2 + is between 4.76%~10.98%, the ratio value of C -1/(C -2+C -3) is between 6.28~21.44.
The northwestern margin of Junggar Basin has been subdivided into three segments with distinctive structural style and geological framework, that is, Hong-Che fault zone, Ke-Bai fault zone and Wu-Xia fault zone. The structural segmentation has resulted in the petroliferous difference between these segments. The north oil and gas pools have formed early and the south later. The adjustment of the upper gas pools has been earlier in the north than south too. The reservoir formation models may be briefly summar.
The structure of Chaoshui basin and Jiuxi basin have better comparability in Mesozoic and Cenozoic: the basins in Mesozoic are both skip and pull apart basins, the basin in Cenozoic are both intracontinental foreland basins, they both develop tenso-shear and extension fault systems in Mesozoic (the boundary is skip fault, the interior of basin is extension fault), they both develop shear-compression and thrust fault systems in Cenozoic, and develop thrust nappe on one side of the basin.
In the present paper are discussed the evidence, mechanism, characteristics and regularity of episodic migration and accumulation of hydrocarbon. It is evidenced that episodic migration and accumulation is rapid, efficient and periodic as a kind of reservoir formation, and therefore significant to the formation of mid-large oil and gas fields. Like gradual migration and accumulation, episodic migration and accumulation is also found to be an important type of reservoir formation and quite common in petroleum.
Biogenic gas, originated from the organic matter’s alteration by microorganism, is natural gas with high contents of CH4, which may be cosmically large-scale occur. Base on the pathway and mechanism of formation, biogenic gas was divided into five different sorts, as follow :early biogenic gas, low mature gas, late biogenic gas,secondary biogenic gas from degradation of crude oil and upgrading gas from secondary alteration of shallow oil and gas, which belonging to pristine and secondary biogenic gas.
Mechanical and chemical factors, which influence fault′s action to fluid, are detailed discussed in this paper. The mechanical factors include mechanical property of fractures, normal stress of fault plane and deformation mechanism of faults, and their actions are as follows: ①The open degree of fault is determined by mechanical property of fractures and normal stress of fault plane; ②It has been testified by tri-axial compression experiments that the higher temperature and pressure, the deeper the deformat...
Based on suggesting the problems for co-mining the coalbed gas and normal petroleum & natural gas, the absorptive effect of the deep coal reservoir under the condition of the balanced water was studied using the physical simulating test with the analysis of the geological setting, and some new viewpoint were suggested. The results showed that the content of the balanced water in coal reservoir could be controlled by the combination of the strata temperature with the its burial depth and coal rank.
Based on the radioactivity of Kalium which generates 40 Ar in source rock through radioactive decay with geologic time passing by, the age accumulation effect of Argon isotope in natural gas pool is founded. For the natural gas from the crust, 40 Ar mainly derives from Kalium-Crust trapping of 40 K. As the age of sourcerock becomes old, the content of the radioactive 40 Ar increases, the 40 Ar/ 36 Ar ratio also increases. The article carries out researches on the two basins--Tarim basin and Ordos basin.
The formation waters contain much higher concentrations of solids in Ordovician, Carboniferous and Triassic reservoirs at Akekule and adjacent, which were considered as forming in a closed hydrogeological environment and disconnected each other. The new concludes are made by the analysis of the isotopes of formation waters:①the isotopes of the formation waters have the same composition; ②the δ 18 O are lighter,δD is from -42.0‰ to -66.0‰ and δ 18 O from 2.7‰ to -6.0‰, maybe composed with surface water.
The unique discovered naturl gas deposit in Kashi sag is Akemomu deposit represented by Ake 1 well. Therefore, it is based on the congregating analysis of Ake 1 well natural gas to research the formation geochemistry of this sag. For this purpose, we use multiple analytic methods analyzing the natural gas of Ake 1 well, at the same time we make a series of gas production experiments with multiple kinds of source rock by using the thermal simulation method. Then we compare the thermal simulation gas and the multiple kinds of source rock.
The pollution of mercury happened at Minamata Bay, Kumamoto town, Japan in 1953 was the first heavy metal pollution event in our history. Since then more attentions have been attracted on mercury pollution and new research findings about it have being emerged in related fields. This paper introduces the variation of mercury content among natural gases, rocks and soils, also states the application of mercury as an index for natural gas identification. The mercury is characterized by high ionic potential.
Hydrocarbon composition and stable carbon isotope composition of natural gas are fractionated by diffusion, dissolution, microbial degradation and cracking in gas reservoirs. The diffusive fractionation is determined by radius and density grads of the hydrocarbon molecules, the dissolving fractionation is controlled by bulk volume and hydration capability of the dissolved molecules. The two kinds of fractionations result in enrichment of heavy molecules in the gases (C~ 2 + ) and heavy carbon isotopic composition.
Deep basin gas accumulations, a type of unconventional gas accumulation, are typically pervasive accumulations. Some of the more important distinguishing characteristics of deep basin gas accumulations include abnormal pressures, low-permeability reservoirs,and a general absence of downdip of water. The Ordos basin is one of the direct types of deep basin gas accumulations. The deltaic deposit constitutes the dominant reservoir in the deep basin. The stratigraphic interval containing the deep basin gas accumulations.
Dalu Lake is a low permeability reservoir.Now it is during the middle period and later period of oil development. To enhance oil recovery.Numerical simulation has been implied into the paper.By means of the theory,the production of various sand reservoirs have been analised here. Based on the problems of various sand reservoirs, EOR including perfection well pattern?decreasing wells ?unsteady injection have been discussed here.Recovery percent of reserves of Ⅳ sand group is the best than the others.
In the natural high-pressure and low-permeability gas reservoir, we find many low producing gas wells′ off-take potential testing material don??t obey traditional binomial expression equation, namely,use binomial equation handling this kind of low producing gas wells?? off-take potential testing material has varying degrees error, some of it may be big. The establishment and application of high-pressure and low-permeability gas well nonlinear stabilization flow equation is this article we study.
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