利用微地震识别水力压裂井旁天然裂缝

Natural fracture identification at hydraulic fracturing wells with microseismic

页岩各向异性强、天然裂缝发育,水力压裂时容易发生套管形变而影响施工进度,利用微地震监测技术可识别造成套管形变的天然裂缝的空间位置,采取工程技术措施,降低施工风险。本文介绍了天然裂缝触发微地震事件的震级、能量、时空分布特征,分析了四川页岩气一口水平井开发水力压裂诱发的微地震事件,施工现场准确地定位出井旁微小天然裂缝的走向和位置,压裂技术人员及时调整施工参数,避免了套管严重形变影响水力压裂进程,为页岩气开发发挥了较好的现场指导作用。

Hydraulic fracturing in shale is usually prone to casing deformation because shale is characterized by strong anisotropy and many tiny-natural fractures.Microseismic can identify positions of these natural fractures.This paper presents one example of this identification.The seismic magnitude,energy,and spatial-temporal features of microseismic events in natural fractures are discussed.Microseismic events from a hydraulic-fracturing horizontal well in Sichuan are analyzed.Natural fractures are accurately predicted on-site and then fracturing parameters are optimized to avoid further casing deformation.Our practice shows that microseismic monitoring has played a guiding role in hydraulic fracturing operations.