双分支水平井酸化技术在碳酸盐岩储层中的应用

为了扩大单井控制面积,提高储层动用程度,增加单井产量,在哈萨克斯坦K油田进行了一口双分支水平井两分支分别酸化措施后合采的先导性试验。根据该油田储层、岩性和物性特征,确定了与储层配伍性较好且具有自转向功能、储层污染小的清洁自转向酸体系作为主体酸。为了达到提高水平段均匀改造程度和后期快速返排的目的,使用了氮气暂堵技术和液氮暂堵技术,并对施工压力、排量、连续油管拖动速度等参数进行了优化。酸化后分析表明,两个分支都起到了酸化解堵、恢复产能的目的,且单支产量与其邻井产量相当,说明双分支水平井酸化工艺在该油田具有较好的应用效果。

Application of acidizing in bi-lateral horizontal well in carbonate reservoir

In order to increase single well control area, producing degree and production of single well, a pilot test of bi-lateral horizontal well acidizing was conduced in K oilfield, Kazakhstan. First, clean self-diverting-acid system was chosen as the main acid, which has self-diverting and little formation pollution, based on the characteristics of the reservoir, lithology and physical properties of this oilfield. Besides, nitrogen and liquid nitrogen were used to temporarily block high permeability layers and make the acidizing more uniform. They can also accelerate flowing back velocity of residual acid. Treating pressure, pumping rate, and coiled tubing drawback velocity were optimized. The analysis after acidizing shows that acidizing worked in plugging removal and productivity restoration in both branches, and the production of single branch equals to its neighbour well separately. This means that bi-lateral horizontal well acidizing can get good application effect in this oilfield.