缝洞型碳酸盐岩油藏重复改造工艺研究与应用

Research and application of refracturing technology in fractured carbonate reservoir

塔河油田开发进程步入提高采收率阶段。建立高导流能力剩余油通道,沟通井周未动用储集体,实现措施井高效重复改造,成为老区剩余油挖潜的当务之急。针对此难题,通过人工裂缝暂堵转向实验,优选了重复酸压工作液及暂堵材料配方,优化了暂堵转向酸压工艺及参数,实现了非主应力方向新缝洞体的沟通动用;通过对酸液类型、浓度及其他参数的优化,形成了深部通道改善技术,实现了修复井筒与远端缝洞体通道、提高采收率的目标。截至目前,矿场试验38井次,成功率98%,累计增油20. 7×104t,投入产出比达到1:3. 1,较常规重复改造工艺降本35%,真正达到了低成本高产出的目的。

The development of Tahe Oilfield has entered the stage of enhanced oil recovery. So establishing the high conductivity remaining oil passages with the undeveloped reservoirs around oil wells becomes a top priority for effectively taping remaining oil. In order to solve this problem, based on experiments for temporary plugging and turning of artificial fracture, after optimizing the acid fracturing fluid, the temporary plugging agent and the technology and parameters of acid fracturing, and a new reservoir body in non-principal stress direction was communicated. Through optimizing the type and concentration of acid fluid and other parameters, a deep channel improvement technology has been formed, which achieves the goal of repairing channels between wellbore and far-end fracture-cave body and enhanced oil recovery. Up to now, 38 well tests have been conducted. The test results indicated that there was a success rate of 98%, a cumulative oil increase of 20.7×10^ 4 t, an input-output ratio of 1:3.1, and a cost reduction of 35% compared with the conventional stimulation process. And then a real goal of low cost and high output has been achieved.