X井区低成本体积压裂技术探索及实践

Exploration into and Practices of Low-Cost Volume Fracturing in Well Block X

X井区三叠系克拉玛依组储层前期为直井注水开发,注水受效不明显,产量递减快,整体采收率低。为充分动用区块剩余油资源,2018年将原有开发方式调整为水平井体积压裂开发,2019年实施的首口井采用连续油管带底封拖动环空压裂,压后单井初期产量较直井提高11.5倍,验证了水平井提产的可行性。自2020年起为适应市场环境需求,在该区块开展矿场试验,逐步将连续油管水力喷射环空压裂转型为桥塞射孔分段压裂,压裂液体由胍胶冻胶过渡为胍胶滑溜水,形成了一套低成本体积压裂技术。应用效果表明:(1)采用不同工艺投产的13口水平井均达到设计产能;(2)使用桥塞射孔+非均匀布孔方式可改善起裂不均衡的问题;(3)通过提升排量可弥补胍胶滑溜水携砂能力差的不足,保证现场施工安全加砂;(4)低成本体积压裂技术可节约压裂成本近三成。

The reservoir of Triassic Karamay Formation in well block X was developed by vertical well water injection in the early stage.As a result,the injection effect was insignificant,the production declined fast,and the overall recovery factor was low. In order to fully produce the remaining oil resources in the block,the original development mode was changed to horizontal well volume fracturing in2018. The first well executed in 2019 was subjected to annulus fracturing using coiled tubing with a bottom packer,and the initial production of single well after fracturing was increased by 11.5 times compared with that of a vertical well. That validated the feasibility of increasing the production of horizontal wells. In order to satisfy market demands,field tests have been carried out in this block since2020. Annulus fracturing using coiled tubing hydraulic jet has been gradually substituted by staged fracturing with bridge plug perforating,and the fracturing fluid has been changed from guar gum gel to guar gum slick water. A set of low-cost volume fracturing technologies has been developed. The application results show that:(1)the 13 horizontal wells put into production using different technologies have all achieved design productivity;(2)uneven fracture initiation can be improved by using bridge plug staged perforating + uneven distribution of perforations;(3)insufficient sand-carrying capacity of guar gum slick water can be made up for by increasing the injection rate to ensure safe sand filling during field treatment;(4)low-cost volume fracturing technology can reduce the fracturing cost by nearly 30%.