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Forming Mechanism And Dominated Factors Of The Reservoir Of The Clastic Rock Of The Upper Paleozoic In Northern Ordos Basin

Posted on:2005-05-07Degree:DoctorType:Dissertation
Country:ChinaCandidate:R E LiuFull Text:PDF
GTID:1100360125952024Subject:Mineralogy, petrology, ore deposits
Abstract/Summary:PDF Full Text Request
By the methods of combining the lab of rock physical simulation with geology theory analysis, the characteristics of the terrigenous clastic rock reservoir of upper Palaeozoic in the north of Ordos Basin have been studied. It reveals the forming mechanism and the key controlling factors of the effective reservoir and establishes the secondary pore evolution models in Ordos Basin. The predicted advantageous exploitation objects by this have changed the exploitation direction in upper Palaeozoic. The results and the creations in the paper are as follows:Based on the outcrop character, lithology character of exploitation well, the regional disconformity interface, the standard character of detrital composition in sandstone and the regional geotectonic background analysis, it is proved that the direction of source is coming from the north of the studied area, and points out the difference of source between the east and the west for the first time.The author bring forward clearly that all sorts of dissolution pores and the residual intergranular pores are the main space of the effective reservoir of upper Palaeozonic in the north of Ordos Basin. The easily-dissolved matters, especially the dissolved of the tuffaceous is the key to form the secondary pores of lower Shihezhi Formation upward in Sulige gas field.It is that the present paper points out the difference of dissolved mechanism between organic acid and inorganic acid. The interaction results of inorganic acid and tuffaceous sandstone produce Kaolinite and Quartz, K+ and Na+ are taken out by liquid and the pores be formed. As for the easily dissolved tuffaceous matters, the dissolution of organic acid is different from inorganic acid. The former can change Al+ of tuffaceous matters into complex compound, and are taken out by the liquid and formed the pores. The tuffaceous mold pores are probably related to the dissolution of tuffaceous matters into organic acid.Using ESEM2020 firstly, the acid dissolved simulation experiment of sorts of sandstone has been done in the field. Under the weak acid medium conditions, the tuffaceous sandstone is easily dissolved, but the feldspar is opposite. The pure sandstone is hardly dissolved, and the amount of dissolution will increases with the rise of the tuffaceous matters.The author put forward firstly four kinds of secondary pore origins, which are the structure microfissure-dissolved digenetic face, the matrix-supported digenetic face, the carbon-dissolved digenetic face, and the siallite-burial-cementing-replacing digenetic face. And it is been established of the secondary pore evolution models of lower Shihezi Formation upwardssandstone reservoirs in Sulige gas field. Two advantageous exploitation objects have been predicted in the south of Yulin and in the north of Tianhuan districts, and there is a potential exploitation object in the west of the foreland.The study in the paper directly lead to the transition of key exploitation from Shenmu district to Yulin , and it brings about great achievements, which gain a series of high-production gas well, with the scale of 2000 X 108m3gas field. Through the study, the north of Tianhuan and the west of foreland basin bring great attention for the oil field leaders.The study results directly lead to the exploitation direction change from Shenmu district to Yulin , and it brings about great achievements, which gain a series of high-production gas well, with the scale of 2000 X 108m3gas field. Through the study, the author provides that the north of Tianhuan and the west of foreland basin are the potential exploitation object. That has brought great attention for the oil field leaders.
Keywords/Search Tags:The north of Ordos Basin, Upper Palaeozonic, Terrigenous clastic rock, Effective reservoir, Secondary pore genetic mechanism, Evolution model, Key controlling factors
PDF Full Text Request
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