Evaluation Of The Upper Paleozoicsource Rocks And Optimizationof Target Area In The Fuxian District

There is huge gas potential in Fuxian area and the upper Paleozoic source rocks are mainly Taiyuan group and Shanxi group.In this paper,the upper Paleozoic source rocks will be analyzed and evaluated from three aspects:organic matter type,organic matter abundanceand organic matter maturity.The geochemical characteristics of source rocks are studied.The contour map of thickness distribution of source rocks is drawn,and the distribution law of source rocks is studied.Combined with the analysis of natural gas accumulation conditions and typical gas reservoir anatomy,the main controlling factors of natural gas enrichment were studied,and the favorable target area of natural gas was optimized.The Taiyuan formation and the Shanxi formation in Fuxian area are mainly composed of vitrinite and inert formations,and the contents of the decomposed mud group and the shell group are few.The organic matter type is mainly type III and II ₂.The content of coal organic carbon is high,and the hydrocarbon generating capacity is strong.Dark mudstone comes next,and its hydrocarbon generation ability is relatively strong,and its supply to natural gas is only coal.The R0 of Taiyuan formation in Fuxian area shows a trend of increasing from north to south,and from east to west.Hydrocarbon source conditions,reservoir conditions,source reservoir assemblages,tectonic setting,cap rock characteristics and migration characteristics are favorable factors for natural gas migration and accumulation.The gas reservoir is dissected through the typical gas wells.After a series of data analysis,it is concluded that the main controlling factors of natural gas enrichment in the upper Paleozoic in Fuxian area include sedimentary microfacies,reservoir physical properties,source rock thickness,reservoir thickness and reservoir distribution.Through the exploration data,the exploration status of the upper Paleozoic is analyzed,and based on the evaluation of source rocks,the Fuxian area is divided into four favorable zones of natural gas generation in Niu Wu,Yichuan,Huangling and Luochuan.The favorable area evaluation standard was established.Through the thickness map of source rock and the thick map of sand body,it was found that the type I favorable area was mainly distributed in the middle of the Niu Wu area;the second kind of favorable areas mainly distributed in the south of the Niu Wu region;the third type favorable areas mainly distributed the Huangling area in Fuxian block and the eastern part of the Luochuan area.