Accumulation Pattern Of Tight Gas Accumulation In Shihezi Formation In Linxing Area

The reservoirs of the Shihezi Formation in Linxing area have typical characteristics of tight gas.Based on thin section identification,experimental analysis,logging interpretation,Seismic data and other geological data,combined with experimental data analysis,comprehensive analysis of geological data,static data and dynamic data,ancient and modern dynamic evolution simulation results.The characteristics of sandstone reservoirs in Upper and Lower Shihezi Formation of Upper Paleozoic in Linxing area were studied,and the conditions of tight gas accumulation were analyzed,and the main controlling factors and accumulation regularity were summarized.The reservoirs of the Shihezi Formation in Linxing area are the typical tight gas reservoirs.The results show that the reservoir porosity is 6.65%and the permeability is0.43mD,which belongs to the typical low porosity and low permeability tight gas resevoirs.It is concluded that the coalbeds of Benxi Formation,Taiyuan Formation and Shanxi Formation are the main source rocks in the study area.Under baking of the Zijinshan rock invasion of early Cretaceous,hydrocarbon source rocks have entered the hydrocarbon generation threshoid and has reached the mature stage of evolution.The source rock Ro>1.25%is the majority,and the hydrocarbon generation intensity is more than10×10~8m~3/km~2,which provides sufficient gas source for reservoir formation.The reservoirs'properties in Shihezi formation vary greatly in space,and the heterogeneity is strong in the longitudinal direction.Sedimentary facies and diagenesis control the distribution and quality of dominant reservoirs.The upper Shihezi Formation deposited a large set of thick purple mudstone,which is a good regional cap rock.Natural gas is mainly vertical migration,microcracks are the main channel of vertical migration,the residual pressure of the source and reservoir is the main driving force of migration.Sedimentary facies and diagenesis control the distribution and quality of dominant reservoirs.Gas is mainly vertical migration,microcracks are the main channel of vertical migration,and the residual pressure of source and reservoirs is the main driving force of migration.The tight gas reservoirs of the Lower Shihezi Formation belong to the near~matching gas reservoirs of the"source and reservoir contact",and the reservoirs in the Upper Shihezi Formation belong to the"reservoir+transport channel"controlled off~site matching gas reservoirs.