Analysis Of Enrichment Conditions Of Natural Gas Accumulation In Upper Paleozoic,Northern Ordos Bain

This thesis aims at clearifying the enrichment conditions of natural gas accumulation on Upper Paleozoic in Hangjinqi area,northern Ordos Basin.Based on the study of the conditions of natural gas accumulation,the main control factors of natural gas accumulation are determined.With the help of restored dynamic accumulation process of natural gas,the natural gas accumulation model is build.Then the enrichment conditions of natural gas accumulation and enrichment regulation of natural gas accumulation are concluded.Finally this paper forecasts the favorable exploration area of natural gas.Firstly,based on the previous achievements,the dissertation summarizes the conditions of natural gas accumulation which include source rock,reservoir,cap rock,trap and migration pathways and so on.By superposing the distribution of natural gas on the conditions of natural gas accumulation,this paper determines the main control factors of natural gas accumulation with the method of the composite.The main control factors of natural gas accumulation are the development degree of source rocks and closed condition of sand-body on Shanxi Formation and Taiyuan Formation.The main control factors of natural gas accumulation are fault and Favorable traps on Lower Shihezi Formation.Secondly,with the help of the software PetroMod,paper simulates the evolutionary process of fault,strata and oil-gas-water flow in the study area.The dynamic accumulation process of natural gas is restored by taking advantage of the contributions of the project.On the basis,three accumulation models are build: source of endogenous store-contact,vertical proximal sourcel and far source trapezium.Thirdly,with the bond of the reserves and gas-soure distance,reservoir facies,degree of late fault activities,source-reservoir-caprock association,infilling periods of natural gas,the enrichment conditions of natural gas accumulation are studied with the method of statistical analysis.On the basis of the accumulation main control factors,the accumulation enrichment regulation is concluded.The development degree of source rocks and favorable sand control gas enrichment of Shanxi Formation and Taiyuan Formation,Oil and gas flow channel and local structure control gas enrichment of Lower Shihezi Formation.Finally,based on the accumulation enrichment regulation,the standard of the favorable exploration area is made.Then this paper forecasts the favorable exploration area.Three favorable exploration area of natural gas is on Shanxi Formation and Taiyuan Formation.Four favorable exploration area of natural gas is on Lower Shihezi Formation.