连续油管多簇喷砂射孔填砂暂堵分段体积压裂技术

MULTISTAGE FRACTURING TECHNIQUE WITH COILED TUBING MULTI-CLUSTER HYDRA JET PERFORATING AND SAND BRIDGING IN HYDRAULIC FRACTURES FOR SHALE GAS RESERVOIRS

目前我国四川地区页岩气水平井压裂过程中普遍使用桥塞分段压裂改造,其原理为桥塞进行机械封隔分段,但遇到套管变形等井下复杂情况时,桥塞在井筒中的通过性成为制约该工艺效率的主要障碍。为解决套变水平井的分段压裂技术难题,在研究不同水平井分段压裂工艺适应性和不足的基础上,提出一套支撑剂缝内屏蔽暂堵分段的新工艺。该工艺通过连续油管多簇喷砂射孔,主压裂后期在裂缝内填砂暂堵分段压裂,实现一次入井多簇射孔和全通径井筒段间封隔,具有工艺简单、作业效率较高、分段分簇不受限制、适用套管变形等多种复杂井下情况等特点。该工艺在川南页岩气示范区A1井等14口井成功应用,实践证明研制的喷射工具多簇喷砂射孔稳定可靠,通过非机械分段方式也能有效实现段间隔离。试验井压后产量优于采用常规速钻桥塞分段压裂的邻井,为今后非常规油气藏同类井的分段压裂改造提供了一种全新的技术手段。

Mechanical isolation with plug and perf is widely used in unconventional reservoir stimulation such as shale gas in Sichuan Basin.But this completion method cannot handle complex downhole conditions such as casing deformation which limited by BHA throughput capacity in the actual drift diameter.This paper proposed an innovative multi-stage fracturing method integrated with coil tubing multi-cluster hydrajet perforating and sand plug temporary bridging which has been developed based on the study of characteristics and suitability of different horizontal well fracturing techniques to solve multi-stage fracturing problems in horizontal wells with casing deformation.This novel technique which is characterized by straight forward process,high treatment efficiency,unlimited stages and clusters is appropriate for casing deformation wells,it has been successfully applied to 14 wells in China’s national demonstration plot of shale gas in Sichuan Basin,which satisfied the requirements of multi-cluster sand jetting perforating and the zonal isolation is also achieved through non-mechanical ways and achieved large SRV(Stimulated Reservoir Volume).Better stimulation performance compared with adjacent well proves it a new way for multistage fracturing of such wells with similar condition in unconventional reservoir development.