高泥质细粉砂岩储层酸液体系的优选及效果评价

OPTIMUM ACID SYSTEM SELECTION FOR HIGHLY ARGILLACEOUS SANDSTONE RESERVOIRS AND PERFORMANCE EVALUATION

某高泥质细粉砂岩油藏储层具有高孔、高渗特点,胶结类型大多为接触式胶结,而且以粉细砂、泥质为主。为有效减小储层的堵塞,解除近井地带泥质及粉细砂造成的渗透率下降,采用基质酸化的方式溶解油层孔隙中的次生矿物质、化学沉淀物等对渗透率有影响的堵塞物质,大幅度提高或恢复井筒附近油层的渗透率,从而获得更高的单井产能,而该技术的关键是优选出适合该区块的酸液体系。文章根据该油藏的储层特征,全面开展了酸液体系优选和评价研究,并进行现场应用,取得了良好的效果。

A highly argillaceous sandstone reservoir introduced herein is featured with high porosity,high permeability,mostly contact cementation,and dominated with fine sands and silts. To effectively reduce clogging in reservoir so as to obviate the nearbore permeability decrease caused by silts and fine sands,the matrix acidizing is often used to dissolve the secondary minerals or chemical precipitates in the reservoir pores to largely improve or restore the permeability near the wellbore and so improve the single-well production rate. The key for this is to select the optimum acid system fit for the block. Based on the characteristics of this reservoir,the comprehensive evaluation of the preferred acid system is made,and the on-site applications have achieved good results.