裂缝性地层压裂降滤失方法研究

Research on reducing fracturing fluid loss in fissured formation

为控制压裂液向天然裂缝的滤失,通过对裂缝性油藏滤失机理的调研,进行了相关的敏感性分析,确定了采取前置液加粉砂的降滤失方法。通过优化前置液体积、粉砂加量、砂浓度、粉砂粒径、施工排量和压裂液黏度,优选出最佳参数以达到降滤失的效果。以ST70井为例对油藏的施工参数进行了优化计算,对比加砂前后的滤失量和滤失速度。结果表明,加砂后滤失量和滤失速度明显降低,验证了粉砂降滤失的效果。这对于提高裂缝性油藏压裂的成功率具有一定的指导意义。

This paper investigates the mechanism of fracturing fluid loss in fissured reservoirs,analyzes relevant sensitivities,and determines a method of fluid loss control by adding silt into prepad fluid.Parameters are optimized to reduce fluid loss,including prepad fluid volume,silt dosage,silt concentration,silt grain size,displacement and fracturing fluid viscosity.Well ST70 was taken as an example to optimize operation parameters and compare fluid loss and filtration velocity before and after adding silt.The result shows evident reduction in fluid loss and filtration velocity,thus verified the effectiveness of fluid loss control by adding silt.This research is helpful to improving the success ratio of fracturing operations in fissured reservoirs.