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Study On The Hydrocarbon Potential Of Paleozoic Source Rock And The Geochemical Character Of Condensate & Gases In The West Ordos Basin

Posted on:2006-05-28Degree:MasterType:Thesis
Country:ChinaCandidate:J F LiFull Text:PDF
GTID:2120360155975816Subject:Petrology, mineralogy, ore deposits
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There are two parts in the west Ordos basin:the both west margin belt and Tianhuan Depressions. Being influced by sedimentary environment and tectonic movement etc,the more difference among the character of the source rocks in Paleozoic stage are expressed out, which influced the potential hydrocarbon of source rock as well as character of condensate and gases.The comclusions include as follows:1. The valid source rockes of upper Paleozoicly distribute in Carboniferous and lower Permian on longitudinal section, organic abundance is heavier and the types of source rock are mainly type Ⅲ. The solube organic matters character of mudstone distinguished expressly from coal, which organic matters of dark argillite can be preserved better because of higher sedimentary water salinity. The result of thermal imitation demonstrate that both the coal and dark argillite have stronger ability to the gasous hydrocarbon and the coal have specific ability to liquid hydrocarbon in upper Paleozoic.2. With the weaker reductive _stronger oxidative sedimentary environments of the source rock , The organic abundance of source rock in Ordovician of lower Paleozoic is poorer and organic types are type Ⅱ2 that the H/C of kerogen is lower and 0/C is heavy. The hydrocarbon generating ability is recovered by means of productivity method and material balance method. It is the ability of generating and expeling hydrocarbon are poorer from carbonate in lower Paleozoic because final productivity of argilanceous carbonate are relatively lower.3. The organic Ro value is varies linear with the present depth in the west margin belt and the same in Mesozonic, and increases more heavy in Paleozoic in Tianhuan Depressions. According to the relationship between tectonic and organic matters, it concluded that the time of tectonical activity was earlier than the thermal evolution suffered.4. By means of Pr/Ph ratio, carbon_isotopic and chromatography_mass spectrographic analsis of normal paraffin, the geochemical character declares that condensate oil come from coal in Upper Paleozoic .Gases in upper Paleozic are mainly coalificational gas in west margin belt , and both δ 13C1 retio and Ro value of the sourse rock in the hanging wall of thrust sheet express that the gases come from higher maturety source rockes in the lower plat of the western margin belt, which the gas had contemporaneeity or balance.5. The gas hydrocarbon of upper Paleozoic source rock is heavier in Tianhuan Depressions, where the Dingbian area is best and Qingyang-Huanxian area is better, and the north Tianhuan Depreeions is weaker. The hydrocarbon generating potential of source rock is weaker in the hanging wall and the heavier relatively in the lower plat of upper Paleozoic in the west margin belt. Because of lower organic abundance, the contribution of source rock in lower Paleozoic is weaker to the gas reserveoir.
Keywords/Search Tags:condensate and gas, geochemacial character, Paleozoic, hydrocarbon source rock, the west Ordos basin
PDF Full Text Request
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