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Characteristics Of Tight Sandstone Reservoir Of Upper Paleozoic In Southern Ordos Basin And Controlling On Gas Accumulation

Posted on:2015-07-14Degree:MasterType:Thesis
Country:ChinaCandidate:L W ZhuFull Text:PDF
GTID:2180330467971307Subject:Mineralogy, petrology, ore deposits
Abstract/Summary:PDF Full Text Request
It’s well-known that low porosity, low permeability and low abundance are the maincharacteristics of tight sandstone reservoir of Upper Paleozoic in the Southern Ordos basin. Onthe basis of the previous researches, by making full use of the geological data such as loggingdata, gas testing data and so on in the study area, under the guidance of the theories ofSedimentology, reservoir geology and the natural gas geology, we make a deeper study of thereservoir characteristics of of Upper Paleozoic in the Southern Ordos basin by combining thegeological theories with the experimental analysis, and making comparison of the static dataand dynamic data, and finally summarize the tight sandstone reservoir controlling effects tothe whole gas pool.The Upper Paleozoic sandstone reservoirs in the study area are mainly composed offine-grained sandstone and median-grained sandstone, and the rock types are dominated byquartz sandstone and quartz-lithic sandstone. Reservoirs become dense after a series ofgeological processes including compaction, cementation and metasomatism. The permeabilitylimits are the same0.1mD for all the four layers in the study area, and the porosity limits are4%for C2b and P1s2while5%for P1s1and P2h8. There is a positive correlation betweenporosity and permeability. The four reservoirs mentioned above all possessed a obviousheterogeneity, and the majority of them belong to the type Ⅱ reservoir, of which theproduction capacity is generally low to medium. The vertical thickness and laterally extendingof these reservoirs are all small, but they superimposed in patches on the section, whichformed a feature of quasi-continuous.In the stable sedimentary background, a relatively high hydrocarbon-generation intensityis the prerequisite of a gas reservoir. The sedimentary environment and sand body distributionbasically controls the distribution range of the gas reservoir, and the areas that have a goodsand body connectivity and reaches the lower limit of effective thickness are favorable for gasenrichment area; due to the reservoirs all have a strong heterogeneity, the reservoirs with goodporosity and permeability are always gas enrichment reservoir.
Keywords/Search Tags:Southern Ordos Basin, Upper Paleozoic, Tight Sandstone Reservoir, Reservoir Characteristics, Controlling Action on Gas Accumulation
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