缝洞型储层酸压改造纤维暂堵规律研究

针对塔河油田缝洞型碳酸盐岩大型复合酸压过程中液体滤失严重的现象,现场提出了纤维暂堵技术。实验利用高温高压酸岩反应流动仪,进行裂缝型储层纤维暂堵性能室内评价。测得不同纤维浓度、长度和不同温度下的定排量最大驱替压差和暂堵时间,研究了温度对纤维降解率的影响。实验结果表明:纤维浓度越大,形成滤饼的承压能力越强,最大驱替压差和暂堵时间越大;较长纤维易缠绕架桥形成滤网,增大渗流阻力,从而增大最大驱替压差和暂堵时间;温度升高,纤维降解速率增快,滤饼致密性降低,最大驱替压差和暂堵时间减小。实验结果对塔河缝洞型油田酸压改造、酸压设计及现场施工都有积极的指导意义。

Research on role of fiber temporary plugging in acid fracturing in natural fracture-cavern system

Large composite acid fracturing is the main stimulation method in Tahe carbonate reservoirs. However, abundant natural fracture-cavern system results in severe acid leak off. The experiment was carried out by acidizing flow instrument to evaluate fiber plugging performance. The maximum differential pressure and plugging time were got under different length and concentration of fiber and different temperature. Experiment results show that maximum differential pressure and plugging time increase with the increasing of concentration of fiber. Longer fibers form fiber cake more easily. Fiber cake can make flow resistance larger. So the maximum differential pressure and plugging time increase. The degradation rate of fibers increase by increasing the temperature, which causes low compactness of fiber cake. So the maximum differential pressure and plugging time decrease. The experimental results have positive significance on the acid fracturing modification, acid fracturing design and site construction in Tahe oil field.