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The Study Of The Sedimentary Facies And Reservoir Characteristics In Chang2Reservoirs From Zhongshanchuan Region Of Ordos Basin

Posted on:2014-11-18Degree:MasterType:Thesis
Country:ChinaCandidate:Y Z PengFull Text:PDF
GTID:2180330467467435Subject:Mineralogy, petrology, ore deposits
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After largely exploration in recent20years, the pressure underneath is seriously insufficient, which leads to the significantly decrease of production in Chang2reservoir of Yanchang formation in oil region of Zhongshanchuan in Ordos Basin. Therefore, it requires us to expand the areas with water flooding in oil region of Zhongshanchuan and use secondary oil recovery to increase the oil production and stabilize the high oil recovery. In this thesis, based on the studies of geology in Zhongshanchuan region, we used geophysical well logging and lithofacies palaeogeography methods to divide and compare Chang2reservoirs. Together with the petrologic study and understandings of the property and the controls of the reservoirs, we attempt to reveal the mechanism of oil and gas accumulation..Referred to the method to divide and compare the Triassic Yanchang Formation in Ordos Basin, through using the mark layer and comparing the cycling and the thickness, we divide Chang2from oil region of Zhongshanchuan into three groups, Chang21, Chang22and Chang23, the latter of Chang21is further divided into Chang21, Chang212and Chang213sub-group, while Chang22oil group is divided into Chang221and Chang222sands group. The oil-bearing reservoir is mainly distributed in Chang212and Chang213; locally indicated in Chang211and Chang22.Through comprehensive geologic study, Chang2are thought to The meandering river facies. Specifically, Chang212develop Meander sand dam, natural levee, Interfluvial lowlands and floodplain.To its east and north, three NE-SW banded distributary channels are developed, with distributary channel sandbodies1.2-5.5km wide, and separated by Interfluvial lowlands and floodplain. Chang213develop Meander sand dam, natural levee and Interfluvial lowlands of these three micro-facies, distributary channel and flood plain, composed of four NE-SW distributary channel sandbodies, about4.3-15km wide. The studied reservoir is mainly composed of medium to fine-grained feldspar sandstone. The physical property of the reservoir is relatively good, with micro-fine throat-like and fine porosity structure.It can bedefined as a low to extra-low permeable reservoir, in which oil is widely present and even superimposed as flakes, and mainly controlled by sedimentary micro-facies, showing a good relationship of source-reservoir-caprock.
Keywords/Search Tags:Ordos Basin, Sedimentary facies, Chang2, Property of Oil reservoir, the type of Oil pool
PDF Full Text Request
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