示踪剂监测技术在暂堵转向压裂中的应用

Application of tracer technology in temporary plugging diverting fracture

优选5种无毒环保、成本低廉以及与压裂液配伍性良好的水溶性有机微量物质示踪剂,对鄂尔多斯盆地北缘L致密砂岩气田分层暂堵转向分层压裂完井的L-A井盒3、盒4段2个压裂层位5个压裂段塞的压裂液返排过程进行了定量监测。分析了压后28d内不同时刻取得的返排水样中各种示踪剂的浓度,通过物质平衡法计算得到了该井笼统及设计的各层、各段塞的压裂液返排效率。结果表明,该井压裂液笼统返排效率为18.3%,设计盒3段压裂液返排效率为10.6%,设计盒4段的为26.4%;设计盒3段前置液的为6.8%、携砂液的为13.4%,暂堵剂的为13.7%;设计盒4段前置液的为28.1%,携砂液的为25.2%。结合储层物性条件、压裂泵注参数等资料对实际泵注及返排过程进行了进一步分析,对该井暂堵转向压裂效果进行了评价。

Five kinds of non-toxic, environmental and low-cost water-soluble tracer element organic tracer which has good compatibility with fracturing fluid has been selected to quantitatively monitor the fracturing fluid flowback procedure of 5 segments, 2 stages in He3 and He4 of temporary plugging diverting stage-by-stage fracture perforated well L-A,L tight sandstone gas filed, north margin, Ordos basin.The concentration of each tracers in flowback liquid sample taken at different post-fracture time during 28 days are analyzed, then the segment-by-segment, stage-by-stage and total flowback efficiency of this well is calculated by the mass balance method.Result showed that the total flowback efficiency of fracturing liquid was 18.3%,for designed fracturing liquid of He3 was 10.6%,of He4 was 26.4%,of pad segment for He3 was 6.8%,of proppant segment for He3 was 13.4%,of temporary plugging agent was 13.7%,of pad segment for He4 was 28.1%,of proppant segment for He4 was 25.2%,further analysis of actual pumping and flowback process was carried out combined with physical properties of reservoir and pumping parameters of fracture, then evaluated the temporary plugging diverting effect.