摘要
为研究水平井分段多簇压裂时裂缝干扰延伸规律,利用改进的位移不连续方法计算多裂缝应力干扰下裂缝宽度,对不可压缩牛顿流体在裂缝中的压力分布进行有限差分处理,结合断裂力学最大周向应力准则模拟裂缝转向延伸,由此建立了水平井多簇同时压裂裂缝干扰流固耦合作用下的裂缝延伸模拟模型。采用牛顿-辛普生迭代方法进行数值模拟求解。结果表明:分段同时压裂裂缝在近井带相互排斥延伸。随着裂缝延伸到相距较远位置,诱导应力影响减弱,裂缝延伸方向逐渐趋向原始最大水平主应力方向。多裂缝同时延伸,每条裂缝最大裂缝宽度相比于单条裂缝延伸时下降了27%,长度相比于单条裂缝延伸增加了22%。分段同时压裂缝内压力高于单条裂缝延伸缝内压力。水平应力差和裂缝间距越小,裂缝之间相互排斥延伸越明显。研究结果揭示了水平井分段多簇同时压裂裂缝延伸规律,为合理设计裂缝间距和压裂规模提供了可靠手段。
In order to study the interference and propagation laws of the fracture for staged multi-luster fractured horizontal well,with the help of the improved displacement discontinuity method,the fracture width was calculated under the condition of the multi-fracture stress interference,the pressure distribution of the incompressible Newtonian fluid in the crack was dealt with by the finite difference,and moreover using the maximum circumferential stress criterion of fracture mechanics,the fracture diversion and propagation were simulated,therefore the simulating model of the fracture propagation for the multi-luster fractured horizontal well under the fluid-solid coupling action interfered by the crack. By means of Newton-Simpson iterative method,the numerical simulation was solved. The results show that when simultaneous fracturing,the fractures repel and spread by each other in the near wellbore zone. As the fracture extending to the position far apart,the effects of the induced stress get weak; the propagation direction of the crack turns to the original maximum horizontal-principal-stress direction gradually. When the multifractures extend together,the maximum width of each fracture decreases by 27% compared with single fracture,while the length increases by 22%. The pressure in the fracture of the simultaneous fracturing is higher than that of the single crack. The less the interval between the horizontal principal stress difference and the fracture is,the more obvious the repellency and propagation among the fractures will be. The study achievements show that the laws have been revealed and furthermore the reliable method is provided for the reasonable designs of the fracture spacing and fractured scale.
作者
胡永全
傅成浩
谭超
赵金洲
任岚
HU Yongquan;FU Chenghao;TAN Chao;ZHAO Jinzhou;REN Lan(State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Chengdu 610500,China)
出处
《大庆石油地质与开发》
CAS
CSCD
北大核心
2018年第5期147-152,共6页
Petroleum Geology & Oilfield Development in Daqing
基金
国家自然科学基金重大项目"页岩气动态随机裂缝控制与无水压裂液研究"(51490653)
关键词
水平井
水力压裂
同时压裂
流固耦合
多裂缝干扰
裂缝延伸
裂缝转向
horizontal well
hydraulic fracturing
simultaneous fracturing
fluid-solid coupling
multi-fracture interference
crack propagation
fracture diversion
