Reservoir Evaluation Of The 8^th Member Of Shihezi Formation In Sudong Area Of Sulige Gasfield

For the problem of low permeability gas reservoir heterogeneity is strong and favorable abundance zone are scattered and difficult to be found,based on the data of geology,logging,logging,core,the paper studies the sedimentary facies and characteristics of reservoirs of the 8^th Member of Shihezi Formation in Sudong area of Sulige gasfield and made a comprehensive evaluation of the reservoir of the 8^th Member of Shihezi Formation in Sudong area of Sulige gasfield by calculating the comprehensive evaluation index.The paper has established a systematic method of reservoir comprehensive evaluation,which provides technical support for the efficient development of the the Sudong area of Sulige gasfield.Through this study,the following results have been achieved:(1)The formation of the 8^th Member of Shihezi Formation in Sudong area is mainly composed of continental braided river sediments.Channel filling and distributary channels are favorable reservoir facies belts.(2)It is believed that the reservoir of the 8^th Member of Shihezi Formation in Sudong area of Sulige gasfield has the characteristics of low porosity,low permeability and low abundance,and the micro pore structure of the reservoir has great difference,such as high displacement pressure,small pore throat radius,poor pore-throat separation,fine skew,non-uniform distribution and poor connectivity.(3)It is believed that the heterogeneity of the reservoir of the 8^th Member of Shihezi Formation in Sudong area of Sulige gasfield is strong.The reservoir heterogeneity is reflected in the drilling rate,thickness and heterogeneity of each layer.The drilling rate and thickness of the 8^th Member of Shihezi Formation under 2 are the largest,and the heterogeneity of reservoir of the 8^th Member of Shihezi Formation under 1 is the strongest.The heterogeneity in the layer is strong.There are three types of rhythm:positive rhythm,compound rhythm and homogeneous rhythminsingle sand body.The effective sand body has three kinds of overlapping modes in the longitudinal direction,such as isolated type,vertical type,and horizontal cutting type.The sand body is spread in a strip in the plane,and the overlapping sand body with larger scale and larger thickness is developed in the local area to form a favorable concentration area.(4)Reservoir thickness,porosity,permeability,gas saturation are the four key factors of reservoir evaluation.Using the analytic hierarchy process toindex system for weight assignment,the comprehensive evaluation index is calculated.So the comprehensive evaluation of the reservoir is carried out,and?+?class accounts for the main part of the block reservoir,proportion reaches 80%.