压裂气井支撑剂回流及出砂控制研究及其应用

加砂压裂是低渗气藏开发评价和增储上产必不可少的技术措施,然而经过大量的现场施工发现,如果压裂后气井排液控制不当或生产过程中配产不合理,将导致支撑剂回流或出砂,引起气井产能严重下降,从而影响最终的压裂效果.分析了支撑剂回流机理,建立了压裂液返排过程中临界返排流量、支撑剂返排速度和沉降速度计算模型,提出了控制支撑剂回流的放喷油嘴选择原则.在考虑气井生产过程中既要返排注入地层中的压裂液,同时又不将地层砂(包括支撑剂)带入井筒的前提下,推导出了压裂气井的临界产量计算公式.结合实际的压裂施工资料进行了实例计算分析,为指导压裂液返排和确定气井合理产能提供依据.

Study on the proppant backflow control and the sanding control of fractured gas wells and its application

Sand fracturing is the necessary technical measures to the development evaluation and the reserves-increasing and output-increasing of low-permeability gas reservoirs. But a lot of field constructions show that, the improper flowing-back control and the irrational allocation of fractured gas wells will lead to the back flow of proppant and the sanding of reservoir, and then cause the reduction of the productivity of the fractured gas wells. Based on the analysis of the mechanism of the proppant backflow, the models for calculating critical flowing-back flow rate, proppant backflow speed and proppant settling rate are established, and the principles for selecting boosting beans to control the proppant backflow are presented. The critical output calculating formula of the fractured gas wells is derived under the presupposition of formation sand and proppant being not carried to wellbore in fracturing fluid flowing-back process. A case is presented, which can guide the flowing-back of fracturing fluid and the determination of the reasonable productivity of fractured gas wells.