Research The Evaluation Of Acid-Fracturing Effect In Fractured Sandstone Gas Reservoir Of Keshen Region

The low permeability fractured sandstone gas reservoirs in the Keshen region are located in Kuqa Depression,Tarim Basin.The reservoir of this region has low permeability,poor physical property,fracture development,strong heterogeneity and low initial producibility,so acid fracturing become the most important technical means to improve the productivity of gas wells.However,the effect of acid fracturing well is quite different.There is a lack of systematic analysis.Therefore,a comprehensive evaluation of the effect of acid fracturing in this block is required.In this paper,based on the analysis of structural features,reservoir profiles and properties,temperature and pressure system and fluid properties,the adaptability of block rock and reservoir properties to acid pressure construction is evaluated.Based on the analysis of acid fracturing state,acid system,acid fracturing process and acid scale,clear the applicability of acid systems of mixed acid solution based on hydrochloric acid and hydrofluoric acid,at the same time,clear the applicability of acid fracturing process,for instance,steering acid fracturing,alternating phase acid fracturing and prepositive acid fracturing.Several acid pressure evaluation methods,such as acid fracturing construction curve method,pressure drop curve analysis method and well testing method,are discussed,and the evaluation method of well testing data before acid fracturing and production data after acid fracturing is put forward according to the actual demand in the field.we systematically evaluate the effect of acid fracturing in Keshen block by using the method discussed in this paper,and look for a regular understanding.Finally,the characteristics of acid fracturing treatment in this block are studied.It plays a guiding role in subsequent acid fracturing treatment and effect evaluation.