收稿日期: 2015-03-29
修回日期: 2015-04-21
网络出版日期: 2015-10-10
基金资助
国家重点基础研究发展计划项目(编号：2013CB228004);国家自然科学基金重大项目(编号：51490653);四川省青年科技基金项目(编号：2012JQ0010)联合资助.
Calculation Model of Kink Angle in Shale Gas Reservoirswith Consideration of Stress Interference
Received date: 2015-03-29
Revised date: 2015-04-21
Online published: 2015-10-10
页岩储层压裂裂缝与天然裂缝相交后，其延伸方向是否改变是决定压裂能否形成复杂缝网的关键因素，转向角增大则有利于与天然裂缝相互连通，最终形成复杂裂缝网络结构。为计算多裂缝扩展时水力裂缝穿过天然裂缝后的转向角，基于线弹性断裂力学理论，建立了考虑远场地应力、裂缝尖端应力集中效应以及多裂缝扩展应力干扰下的页岩储层裂缝与天然裂缝相交后转向角计算模型。通过对比已有单缝模型，发现考虑多缝扩展产生诱导应力时，水力裂缝穿出天然裂缝后的转向角将增大，且裂缝长度、裂缝间距、天然裂缝分布位置、缝内净压力都影响转向角的大小。该模型可用于水平井多段压裂和井工厂压裂裂缝转向角计算，评价缝网压裂可行性、指导缝网压裂设计。
李勇明，王琰琛，赵金洲，许文俊 . 考虑多缝应力干扰的页岩储层压裂转向角计算模型[J]. 天然气地球科学, 2015 , 26(10) : 1979 -1983 . DOI: 10.11764/j.issn.1672-1926.2015.10.1979
The complexity of hydraulic fracture network in shale gas reservoir depends on the behaviors of hydraulic fractures as they intersect natural fractures.The larger of the kink angle,the more likely to form the complex fracture network.The model of kink angle with consideration of remote stress,stress intensity near the tip of fracture and stress interference of multi-fractures is established based on linear elastic fracture mechanics.Compared with the existing single fracture models,the kink angle is larger,meanwhile,length and space of fractures,distribution position of natural fracture as well as net pressure are principal factors affecting kink angle.The model not only can be used in the analysis of kink angle in “well plant” fracturing and multi-cluster fracturing in horizon well,but also can evaluate the feasibility of network fracturing and guide the development programme of network fracturing.
Key words： Shale gas; Stress interference; Network fracturing; Kink angle
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