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The Reasearch On Accumulation Mechanisms Of Subtle Reservoirs In Toutunhe Formation, Central Jungger Basin

Posted on:2010-05-23Degree:MasterType:Thesis
Country:ChinaCandidate:M JiFull Text:PDF
GTID:2120360278960853Subject:Mineral prospecting and exploration
Abstract/Summary:PDF Full Text Request
For the purpose of predicting the hydrocarbon potential and providing theory reference for exploration practice, the accumulation mechanism of subtle reservoir in Toutunhe Formation (J2t) in central Jungger Basin was about the researched intensively according to the theory and methods about petroleum migrating and accumulating. The new recognaizations mainly related to layers and sandbodies distribution, reservoir development, hydrocarbon migrating and accumulating mechanism, and the controlling factors of petroleum enrichment. Especially in the analysis of the relation of Che-Mo palaeohigh and accumulation, some new and peculiar ideas were suggested.The main research results are as follows: (1)The remained formation of J2t, which distributed limitedly, was with fluvial facies and thin thickness. The connectivity of sanddodies is poor and changes fast vertically. The reservoir is serious heterogeneity with extra low-low porosity and extra low-middle permeability. (2) The oil source of Toutunhe Formation was from Permian, the multiphase generation of hydrocarbon caused multiphase accumulation. On the whole, the reservoir conditions were not very good, but the sealing conditions were good; the reservoir heterogeneity affected the hydrocarbon accumulation and distribution certainly; because of barrier beds, water/oil interfaces were very complex. (3) The type of traps was variety in the area where was in good condition of forming subtle reservoirs, such as structural-lithological reservoirs, lithological reservoirs and so on. The formation of subtle reservoirs was mainly controlled by the Che-Mo palaeohigh evolution, fluid transporting conditions and entrapment conditions. The distance from source to traps was very long, and the transporting channels were variety. Connected sandbodies were the main lateral channels; deep and shallow faults formed the vertical channels; the micro-fissures created by extrapressure were the important channels for the Jurassic Formation less of faults; the unconformity of Cretaceous and Jurassic was the most significant channels for the petroleum accumulation in J2t, and interlayer minor faults and connected sandbodies confined the oil and gas migration and accumulation. (4) The evolution of Che-Mo palaeohigh not only caused the thin remained thickness, poor reservoir conditions and low traps of J2t, but also resulted the regional unconformity of the top and bottom of J2t and provided migration pathway and trap condition. Che-Mo palaeohigh also was the critical factor of depositional system and influenced the development of reservoir. The evolution of palaeohigh resulted the regulation and damage of accumulations and the multiphase migrating and accumulating in research area, that the processes from the north to the south changed late gradually. There were mainly stratigraphic hydrocarbon reservoirs in the south of palaeohigh and lithologic hydrocarbon reservoirs in the north, the petroleum accumulating models in different place were different.
Keywords/Search Tags:Toutunhe Formation, Che-Mo palaeohigh, accumulation mechanism, Subtle reservoir, Jungger Basin
PDF Full Text Request
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