摘要
随着油气探采深度和难度的增加,常需要配合压裂技术,以提高产能,射孔和储层参数是影响压裂效果的主要因素。对标经典真三轴压裂模拟试验,建立扩展有限元压裂模型,验证、完善扩展有限元模型分析压裂效果的适用性,并分析射孔和储层参数对压裂裂缝扩展规律的影响。研究结果表明:射孔角度0°~75°,起裂压力先减小后增大,30°时最小为36 MPa,75°时最大为41.9 MPa,变化幅度16.4%;裂缝宽度由0.0138 m减小到0.0033 m,降幅76.1%;裂缝长度先减小后增大,45°时最小23.54 m,0°时最大25.45 m。射孔深度0.6~1.8 m时,起裂压力由47.7 MPa减小到39.79 MPa,变幅24.1%;裂缝宽度的变幅小于4%。水平地应力差0~7 MPa时,起裂压力由32.97 MPa增大到41.04 MPa,增幅19.7%;裂缝宽度由0.01312 m减小到0.00686 m,降幅47.7%;裂缝长度由24.5 m减小到23.8 m,降幅2.9%。弹性模量10~16 GPa,起裂压力变幅0.43%;裂缝宽度增幅25.4%,裂缝长度增幅35%。抗拉强度1~6 MPa时,起裂压力由37.58 MPa增大到48.22 MPa,增幅28.3%,裂缝宽度增幅27%,裂缝长度降幅21%。弹性模量10~17 GPa,裂缝宽度降幅17.3%,裂缝长度增幅23.1%。研究结果可为优化压裂参数提供参考。
As the depth and difficulty of oil and gas exploration and production increases,fracturing is usually needed to be conducted to improve productivity.Perforation and reservoir parameters are the main factors affecting the fracturing effect.Benchmarking against the classic true triaxial fracturing simulation test,an extended finite element fracturing model was built.The applicability of the extended finite element model in analyzing the fracturing effect was verified and improved.Finally,the influence of perforation and reservoir parameters on the propagation law of induced fractures was analyzed.The research results show that when the perforation angle changes from 0°to 75°,the fracture initiation pressure first decreases and then increases.When the perforation angle is 30°,the fracture initiation pressure is the minimum,i.e.,36 MPa;75°,the maximum,i.e.,41.9 MPa,with a variation amplitude of 16.4%.The fracture width decreases from 0.0138 m to 0.0033 m,with a decrease amplitude of 76.1%.The fracture length first decreases and then increases,and is the minimum,i.e.,23.54 m at 45°perforation angle,and the maximum,i.e.,25.45 m at 0°perforation angle.When the perforation depth changes from 0.6 m to 1.8 m,the fracture initiation pressure decreases from 47.7 MPa to 39.79 MPa,with a variation amplitude of 24.1%;and the variation amplitude of fracture width is less than 4%.When the horizontal ground stress difference changes from 0 MPa to 7 MPa,the fracture initiation pressure increases from 32.97 MPa to 41.04 MPa,an increase of 19.7%;the fracture width decreases from 0.01312 m to 0.00686 m,a decrease of 47.7%;the fracture length decreases from 24.5 m to 23.8 m,a decrease of 2.9%.When the elastic modulus changes from 10 GPa to 16 GPa,the fracture initiation pressure changes by 0.43%,and the fracture width and length increase by 25.4%and 35%,respectively.When the tensile strength changes from 1 MPa to 6 MPa,the fracture initiation pressure increases from 37.58 MPa to 48.22 MPa,an increase of 28.3%,the fracture width i
作者
李明飞
张超
黄文鑫
张伟
梁经纬
窦益华
Li Mingfei;Zhang Chao;Huang Wenxin;Zhang Wei;Liang Jingwei;Dou Yihua(Mechanical Engineering College,Xi'an Shiyou University;Xi'an Key Laboratory of Wellbore Integrity Evaluation;PetroChina Tarim Oilfield Company;College of Petroleum Engineering,Xi'an Shiyou University)
出处
《石油机械》
北大核心
2024年第12期62-72,共11页
China Petroleum Machinery
基金
国家自然科学基金项目“高温高压气井完井管柱特殊螺纹接头密封面微动磨损及能量耗散机理研究”(52274006)
低渗透油气田勘探开发国家工程实验室开放课题“页岩油水平井压裂过程中套损机理研究”(2023014)。
关键词
压裂
射孔和储层参数
边界扩展
起裂压力
裂缝宽度
裂缝长度
fracturing
perforation and reservoir parameters
boundary extension
fracture initiation pressure
fracture width
fracture length
