钻井岩屑回注作业中裂缝扩展规律  

Fracture Propagation Law in Drilling Cuttings Reinjection Operations

作　　者：李斌[1] 严海源[1] 严卫杰 雷克[1] 石成辉 张贵磊[1] 张帅 冯永存[2] LI Bin;YAN Hai-yuan;YAN Wei-jie;LEI Ke;SHI Cheng-hui;ZHANG Gui-lei;ZHANG Shuai;FENG Yong-cun(China Oilfield Services Co.,Ltd.,Langfang 065201,China;College of Petroleum Engineering,China University of Petroleum(Beijing),Beijing 102249,China)

机构地区：[1]中海油田服务股份有限公司,廊坊065201 [2]中国石油大学(北京)石油工程学院,北京102249

出　　处：《科学技术与工程》2022年第25期10958-10967,共10页Science Technology and Engineering

基　　金：国家自然科学基金面上项目(52074312);中国石油大学(北京)科研基金(2462019YJRC008)。

摘　　要：岩屑回注技术是有效处理钻井废弃物并消除其对环境影响的重要手段。该技术将岩屑进行研磨处理,然后与海水或油田废水充分混合,使之成为稳定的浆体,利用水力压裂的手段将其注入并永久封存到合适的地层中。然而,由于岩屑回注作业间歇施工的特点,施工过程中所产生的诱导裂缝与水力压裂裂缝有明显区别。系统研究岩屑回注过程中裂缝扩展规律是实现安全、高效的岩屑回注作业的关键。在开源软件PyFrac基础上进行二次开发,将裂缝的有限离散化与稳定扩展的半无限水力裂缝的近端渐近解相结合,实现了岩屑回注诱导裂缝扩展模拟功能。基于此模型,开展了不同施工参数条件下裂缝扩展数值模拟研究。结果表明,回注作业排量与裂缝尺寸呈正相关关系;注入速度、总注入量、回注液黏度和回注间歇时间对裂缝宽度影响程度依次减弱。Cuttings reinjection technology is an important means to effectively deal with drilling waste and eliminate its impact on the environment. The technology grinds the rock cuttings and fully mixes them with seawater or oilfield wastewater to form a stable slurry, which is injected and permanently sealed into a suitable formation by means of hydraulic fracturing. However, due to the intermittence of cuttings reinjection operation, the induced fractures in the process of construction are obviously different from hydraulic fracturing fractures. It is the key to realize the safe and efficient operation of cuttings reinjection to systematically study the law of fracture propagation in the process of cuttings reinjection. Based on the open source PyFrac software, the secondary development was carried out to realize the simulation function of fracture propagation induced by cuttings reinjection. The finite discretization of fracture was combined with the proximal asymptotic solution of semi-infinite hydraulic fracture, which can improve the calculation accuracy of rough grid. Based on this model, the numerical simulation of crack propagation under different construction parameters was carried out. The simulation results show that the displacement of reinjection operation is positively correlated with fracture size. The influence of injection rate, total injection volume, viscosity of reinjection fluid and interval time on fracture width decreases in turn.

关 键 词：岩屑回注 裂缝扩展 裂缝宽度 

分 类 号：TE319[石油与天然气工程—油气田开发工程]