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Gas Reservoir Forming Conditions Of Lower Paleozoic Of Luochuan And Adjacent Area In Ordos Basin

Posted on:2009-07-27Degree:MasterType:Thesis
Country:ChinaCandidate:Y LiuFull Text:PDF
GTID:2120360242488289Subject:Mineral prospecting and exploration
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Luochuan and adjacent area locate in the south of Ordos Basin,which crossed two tectonic units,North Wei River Uplift and Yishan Slop.For the study area is located in the east slop of arcuate zone,composed of Central Uplift and South Uplift of lower Paleozoic,in which Jingbian gas field is also locate,the study area and Jingbian gas field should exist the similar gas reservoir forming conditions.Therefore, the systematic study of petroleum geology of lower Paleozoic in Luochuan and adjacent area is helpful to the objective evolution for gas exploration target,and also provides the basis for gas exploration target optimization.By comprehensive application of the basic scientific knowledge and theory of sedimentology,organic geochemistry of source rock,reservoir geology,according to the analysis and testing date of organic geochemistry,the identification data of rock thin section,casting thin section,fluorescence thin sections,and the testing data of porosity,permeability and saturation,the sedimentary facies,source rock,reservoir, reservoir-seal assemblage of lower Paleozoic in Luochuan and adjacent area were given objective analysis and evaluation.The following are the main achievements: In Ordovician,study area was separated into two phase region:south phase region and north phase region by the saddle between Central Uplift and Hancheng old land,and the separation line is approximately in the line of Zhengning - Huangling -Huanglong.South phase region was showing a carbonate gentle slop sedirnentary model with steep end in outer shelf,and north phase region was showing a basin margin sedimentary model in inner shelf.The type of organic matter of lower Paleozoic in study area is typical marine organic matter,andâ… - type kerogen is the main type andâ…¡- type kerogen is little; The mudstone and marl of slop facies in Pingliang formation in south of study area is the best source rock,and the carbonate rock of Majiagou formation of ointm.ent-salt lake and ointment-dolomite flat in the north of study area is good source rock. The maturity of various source rocks of lower Paleozoic are all in high-over matured stage,so the source rocks of lower Paleozoic in the study area is in dry gas-generating stage.There are four carbonate reservoirs types on lower Paleozoic in study area, which are grain limestone reservoir,penecontemporaneous dolomite reservoir, marine-meteoric mixing dolomite reservoir and burial dolomite reservoirs.The study indicates that penecontemporaneous dolomite and marine-meteoric mixing dolomite reservoirs are the best reservoir types,the next is burial dolomite reservoir,and the gain limestone reservoir has relatively worse physical property.Two reservoir-seal assemblage types were classified on lower Paleozoic,and one is weathering crust reservoir-seal assemblage,another is inner carbonate reservoir-seal assemblage.By synthesize evaluation,Majiagou5 section weathering crust reservoir-seal assemblage and Majiagou inner carbonate reservoir-seal assemblage are considered as potential reservoirs.
Keywords/Search Tags:Ordos Basin, Luochuan area, Lower Paleozoic, Gas, Reservoir Forming Conditions
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