国外页岩气井水力压裂裂缝监测技术进展

Technical Progress in Overseas Hydraulic Fracture Monitoring Techniques for Shale Gas Well

由于页岩气储层呈低渗物性特征,需要进行储层改造才能获得工业价值的天然气流。页岩气储层经过水力压裂产生的人工裂缝是页岩气产出的主要通道,通过裂缝监测手段可以确定裂缝的延伸特征,利用这些信息优化压裂设计,实现页岩气藏管理的优化。通过调研分析国外文献,可知目前国外常用的页岩气井水力压裂裂缝监测主要有直接近井筒裂缝监测、井下微地震监测方法、测斜仪监测和分布式声传感裂缝监测,对比分析了这几种裂缝监测方法的监测能力和适应性。在这些压裂监测技术中直接近井筒裂缝监测技术只作为补充技术,井下微地震裂缝监测是目前应用最广泛、最精确的方法,测斜仪裂缝监测的应用也比较广泛但无法用于深井,分布式声传感裂缝监测在2009年首次用于现场压裂监测还处于起步阶段。先进页岩气井水力压裂裂缝监测技术的应用大大增加了水力压裂增产措施的有效性和经济性。

Shale gas reservoirs have to be transformed by hydraulic fracturing to get industrial value of gas flow because of shale's low permeability.Artificial fractures resulted from hydraulic fracturing are main channels for shale gas production.Extension features of artificial fractures can be determined by means of fracture monitoring technologies,which are useful for fracturing design optimization and useful for optimizing management on shale gas production.Investigated and analyzed are relative information on shale gas in foreign literatures and results show that hydraulic fracture monitoring technologies used frequently for shale gas wells in other countries at present mainly include conventional near-wellbore fracture-diagnostic technique,microseismic monitoring technique,tiltmeter monitoring technique and distributed acoustic sensing(DAS) monitoring technique.Analyzed are adaptability and monitoring capability of these fracture monitoring technologies.Among these technologies,the conventional near-wellbore fracture-diagnostic technique is only used as a complementary method,the microseismic monitoring technique,widely used in shale gas well hydraulic fracturing at present,is the most accurate method.The tiltmeter monitoring technique is also used widely,but it can't be applied for deep wells.The distributed acoustic sensing(DAS) monitoring technique,used initially in field fracture monitoring in 2009,is still in its initial stage.Application of advanced fracture monitoring techniques to shale gas hydraulic fracturing will enhance the effectiveness and economical efficiency of hydraulic fracturing stimulation treatment.