甲烷原位燃爆压裂数值模拟研究  

Numerical simulation study of methane in situ deflagration fracturing

作　　者：王旭东 曲占庆[1] 王继伟 郭天魁[1] 石一曼 WANG Xu-dong;QU Zhan-qing;WANG Ji-wei;GUO Tian-kui;SHI Yi-man(School of Petroleum Engineering in China University of Petroleum,Qingdao 266580,Shandong,China;China Offshore Oil International Co.,Ltd.,Beijing 100028,China)

机构地区：[1]中国石油大学(华东)石油工程学院,山东青岛266580 [2]中国海洋石油国际有限公司,北京100028

出　　处：《工程爆破》2023年第6期33-43,共11页Engineering Blasting

基　　金：国家重点研发计划基金资助项目(2020YFA0711800)。

摘　　要：为了探究燃爆压裂裂缝的扩展规律,通过块体离散元与有限元结合的连续-非连续单元法建立甲烷燃爆冲击致裂数学模型。基于朗道爆源模型描述燃爆压力变化,利用线弹性-断裂本构模型描述岩石基质的力学行为。基于建立的燃爆压裂数值模型,进行了直井、水平井和层内的燃爆压裂数值模拟,分析了直井燃爆压裂的裂缝扩展规律以及段间距、燃爆段长、工艺方法等因素对水平井燃爆压裂裂缝扩展规律的影响以及层内从单级到多级燃爆的变化规律。结果表明:直井燃爆压裂产生多条径向裂缝;优选缝间距为5 m、适当增加燃爆段长、选择分步燃爆的压裂工艺,可以取得更大的破裂度和裂缝范围;层内多级燃爆压裂提高储层破裂度7%以上,破裂范围实现x方向增加2.68倍,y方向增加3.8倍,大幅度提高页岩气渗流能力。In order to explore the law of fracture propagation in deflagration fracturing,a mathematical model of methane deflagration impact cracking was established by the continuous-discontinuous element method combined with block discrete element and finite element.The Landau detonation source model is used to describe the variation of the detonation pressure,and the linear elastic-fracture constitutive model is used to describe the mechanical behavior of rock matrix.Based on the established numerical model of deflagration fracturing,the numerical simulation of deflagration fracturing in vertical Wells,horizontal Wells and reservoirs was carried out.The fracture propagation law of vertical well deflagration fracturing,the influence of stage spacing,deflagration stage length,technology and other factors on the fracture propagation law of horizontal well deflagration fracturing,and the variation law from single stage to multistage deflagration in the formation are analyzed.The results show that multiple radial fractures are produced by deflagration fracturing in vertical Wells.The fracture spacing is 5 meters,the length of deflagration stage is increased appropriately,and the fracturing process of deflagration step by step is selected,which can achieve greater fracture degree and fracture range,appropriately increasing the length of the explosion section,and selecting the fracturing process of step-by-step explosion.Multistage deflagrant-fracturing in the reservoir increases the reservoir fracture degree by more than 7%,and the fracture range increases by 2.68 times in the x direction and 3.8 times in the y direction,greatly improving the shale gas seepage capacity.

关 键 词：燃爆压裂 页岩气 连续-非连续单元法 破裂度 

分 类 号：TE357[石油与天然气工程—油气田开发工程]