摘要
通常页岩井采收率约为10%~16%,远远低于常规油气藏。目前国际油价低迷,页岩井产量递减速度较快,对于有效经济开采提出了更高的技术要求。由于岩石蠕变,压裂不完善,裂缝导流能力降低等地质、工程因素导致产量降低,运用页岩重复压裂技术能够实现增产,且费用低,效果显著。根据页岩改造大规模、大排量、水平段长等特点,对比不同重复压裂工艺技术,采用可降解暂堵材料快捷方便且价格低,然而运用Eseal工具工序较多,费用高。有效封堵已射孔眼,通常每孔2.3 kg暂堵材料,优化重复压裂设计,重新射孔,利用桥塞/暂堵材料分段分级压裂,暂堵效果明显。连续油管带Eseal工具下入至目的井深,封堵产能无贡献段,重建井筒内的完整性,重新射孔,再次压裂。基于国外重复压裂现场应用总结了重复压裂选井标准及时机选择,页岩重复压裂技术已成功应用于Marcellus,Haynesville,Barnett,Eagle Ford等区块的直井与水平井,大部分井增产效果显著,较前期提高65%以上。
Usually shale recovery ratio is about 10%-16%,which is far less than the conventional oil and gas reservoirs.Because the current international oil prices are in the doldrums and shale production declines fast,higher technical requirements are put forward for effective economic exploitation.Because of the geological and engineering factors such as the creep of rock,the imperfection of fracturing and the decrease of the conductivity of fracture,leading to the decrease of production,the repeated fracturing technique can realize the increase of production,and the cost is low and the effect is remarkable.According to the characteristics of shale,as large-scale,large delivery rate and large segment length,comparing the different refracturing techniques,the use of biodegradable temporary plugging material is convenient and with low cost,but the use of Eseal tools is more procedures and with high cost.Temporary plugging technology is that the target layer is perforated to refracture and establish the passage.When the particulate drops with 2.3 kg per perforation usually are used to plug perforations firstly and the refracturing design is optimized,the well is perforated again and the bridge plugs/the particulate drops are used to refracture.Sealing pressure response is obvious.Eseal tools is that the coiled tubing with Eseal tool is used to enter the goal of the well to seal up the section of no productivity and reconstruct the integrity of the wellbore,then the well is perforated and fractured again.Shale refracturing technology has been successfully applied in vertical wells and horizontal wells in Marcellus,Haynesville,Barnett,Eagle,Ford and other blocks,and most of the wells have remarkable effects of increasing production,which has increased by more than 65%compared with the early days.
作者
曾凌翔
郑云川
蒲祖凤
ZENG Lingxiang;ZHENG Yunchuan;PU Zufeng(CCDC Downhole Service Company,Chengdu,Sichuan 610051,China)
出处
《钻采工艺》
CAS
北大核心
2020年第1期65-68,I0005,共5页
Drilling & Production Technology
基金
“十三五”国家科技重大专项“长宁-威远页岩气开发示范工程”之课题5“复杂山地工厂化钻完井作业模式与应用”(编号:2016ZX05062-05)
中油油服统筹科技项目“川渝页岩气综合提速提效压缩工期综合配套技术研究-页岩气压裂施工参数优化提速研究”(编号:2019T-003-002-3)
川庆科技项目“威远页岩气重复压裂技术研究”(编号:CQ2019B-24-4-4)
井下作业公司科技项目“页岩气加砂压裂施工预警技术及配套软件研究”(编号:JX2019-4)。
