文章摘要
裂缝性基岩气藏水力压裂起裂压力与近井形态研究
Fracture Initiation Pressure and Near-wellbore Fracture geometry of Hydraulic Fracturing in Bedrock Gas Reservoirs with Natural-fracture
投稿时间:2019-08-14  修订日期:2019-08-14
DOI:
中文关键词: 天然裂缝  压裂  起裂压力  裂缝形态  应力强度因子
英文关键词: natural  fracture initiation  pressure fracture  geometry stress  intensity factor  transverse fracture
基金项目:中国石油天然气股份公司重大专项“柴达木盆地建设高原大油气田勘探开发关键技术研究与应用”(2016E-01);项目主持人:张道伟
作者单位E-mail
刘 永 中国石油青海油田公司钻采工艺研究院 277906947@qq.com 
刘世铎 中国石油青海油田公司钻采工艺研究院 shiduoliupetro@petrochina.com.cn 
林 海 中国石油青海油田公司钻采工艺研究院 linhai_qinghai@petrochina.com.cn 
万有余 中国石油青海油田公司钻采工艺研究院 youyuwanzcy@petrochina.com.cn 
刘 欢 中国石油青海油田公司钻采工艺研究院 liuhuanpetrozy@petrochina.com.cn 
任广聪 中国石油大学北京石油工程学院 renguangcongcup@163.com 
陈 铭 中国石油大学北京石油工程学院 xmcm0122@126.com 
摘要点击次数: 6
全文下载次数: 
中文摘要:
      为明确裂缝性基岩气藏水力压裂起裂压力和裂缝起裂形态,基于断裂力学原理,采用加权函数法,建立横切天然裂缝与纵向天然裂缝应力强度因子解析公式,并提出天然裂缝地层起裂压力模型。采用高斯数值积分和二分法求解非线性积分方程,并编制计算程序,通过与有限元结果对比,验证了模型合理性。基于该模型,计算分析了天然裂缝长度、岩石断裂韧性和地应力对起裂压力的影响规律,研究表明:横切天然裂缝越长,起裂压力越低,而纵向天然裂缝起裂压力随缝长增大先下降后上升;天然裂缝越长,越容易发生横切缝起裂,而近井存在较短纵向天然裂缝时,纵向天然裂缝会优先起裂。岩石断裂韧性越小,横切天然裂缝起裂压力越低;高断裂韧性有利于纵向天然裂缝起裂。纵向缝在高应力差时起裂压力高,难以起裂。高垂向应力条件纵向缝起裂压力降低,因而高垂向应力条件近井容易形成纵向缝。研究结果可为裂缝性基岩气藏压裂设计提供理论依据。
英文摘要:
      To investigate fracture initiation pressure and fracture geometry of hydraulic fracturing in bedrock gas reservoirs, analytical formula of stress intensity factor for transverse natural fractures and longitudinal natural fractures were established based on weight function method in fracture mechanic, and then mathematical model for fracture initiation pressure was proposed. The Gauss integral and bisection method are used to solve the nonlinear integral equation, and the calculation program is compiled. The accuracy of the model was verified by comparing with the finite element numerical simulation results. Based on this model, the influence of natural fracture length, fracture toughness and in-situ stress is calculated and analyzed. The results show that the lager the length of near-wellbore transverse natural fractures, the easier the transverse fracture will initiate. While the existence of near-wellbore longitudinal natural fractures favor the initiation of longitudinal fracture. Smaller fracture toughness and vertical in-situ stress favors the initiation of transverse fractures compared to longitudinal ones. High stress difference results in high initiation pressure of longitudinal factures, and the transverse fracture initiate easier. The research can provide theoretical basis for fracturing design of bedrock gas reservoir with natural fractures.
View Fulltext   查看/发表评论  下载PDF阅读器
关闭

手机扫一扫看 分享按钮