In this study,a fully coupled hydromechanical model within the extended finite element method(XFEM)-based cohesive zone method(CZM)is employed to investigate the simultaneous height growth behavior of multi-cluster hy...In this study,a fully coupled hydromechanical model within the extended finite element method(XFEM)-based cohesive zone method(CZM)is employed to investigate the simultaneous height growth behavior of multi-cluster hydraulic fractures in layered porous reservoirs with modulus contrast.The coupled hydromechanical model is first verified against an analytical solution and a laboratory experiment.Then,the fracture geometry(e.g.height,aperture,and area)and fluid pressure evolutions of multiple hydraulic fractures placed in a porous reservoir interbedded with alternating stiff and soft layers are investigated using the model.The stress and pore pressure distributions within the layered reservoir during fluid injection are also presented.The simulation results reveal that stress umbrellas are easily to form among multiple hydraulic fractures’tips when propagating in soft layers,which impedes the simultaneous height growth.It is also observed that the impediment effect of soft layer is much more significant in the fractures suppressed by the preferential growth of adjoining fractures.After that,the combined effect of in situ stress ratio and fracturing spacing on the multi-fracture height growth is presented,and the results elucidate the influence of in situ stress ratio on the height growth behavior depending on the fracture spacing.Finally,it is found that the inclusion of soft layers changes the aperture distribution of outmost and interior hydraulic fractures.The results obtained from this study may provide some insights on the understanding of hydraulic fracture height containment observed in filed.展开更多
The focus of this study is to analyze a parametric space for the problem of a constant height hydraulic fracture driven by a power-law fluid.The interplay of physical mechanisms related to toughness,fluid resistance,a...The focus of this study is to analyze a parametric space for the problem of a constant height hydraulic fracture driven by a power-law fluid.The interplay of physical mechanisms related to toughness,fluid resistance,and leakoff is considered,but the model is restricted to local elasticity for simplicity.The problem of a semi-infinite constant height fracture is first analyzed:limiting solutions are obtained analytically and their locations inside the dimensionless parametric space are obtained.Then,the problem of a finite constant height fracture is investigated.Similarly,limiting vertex solutions are first outlined and then their locations in the parametric space are quantified.Results demonstrate that the effect of the power-law factor is relatively mild,as it does not significantly distort the parametric spaces.At the same time,there are quantitative differences,which are also determined by the obtained results.Numerical examples highlighting the effect of fracture regime on morphology of multiple fractures are presented at the end.展开更多
文摘In this study,a fully coupled hydromechanical model within the extended finite element method(XFEM)-based cohesive zone method(CZM)is employed to investigate the simultaneous height growth behavior of multi-cluster hydraulic fractures in layered porous reservoirs with modulus contrast.The coupled hydromechanical model is first verified against an analytical solution and a laboratory experiment.Then,the fracture geometry(e.g.height,aperture,and area)and fluid pressure evolutions of multiple hydraulic fractures placed in a porous reservoir interbedded with alternating stiff and soft layers are investigated using the model.The stress and pore pressure distributions within the layered reservoir during fluid injection are also presented.The simulation results reveal that stress umbrellas are easily to form among multiple hydraulic fractures’tips when propagating in soft layers,which impedes the simultaneous height growth.It is also observed that the impediment effect of soft layer is much more significant in the fractures suppressed by the preferential growth of adjoining fractures.After that,the combined effect of in situ stress ratio and fracturing spacing on the multi-fracture height growth is presented,and the results elucidate the influence of in situ stress ratio on the height growth behavior depending on the fracture spacing.Finally,it is found that the inclusion of soft layers changes the aperture distribution of outmost and interior hydraulic fractures.The results obtained from this study may provide some insights on the understanding of hydraulic fracture height containment observed in filed.
文摘The focus of this study is to analyze a parametric space for the problem of a constant height hydraulic fracture driven by a power-law fluid.The interplay of physical mechanisms related to toughness,fluid resistance,and leakoff is considered,but the model is restricted to local elasticity for simplicity.The problem of a semi-infinite constant height fracture is first analyzed:limiting solutions are obtained analytically and their locations inside the dimensionless parametric space are obtained.Then,the problem of a finite constant height fracture is investigated.Similarly,limiting vertex solutions are first outlined and then their locations in the parametric space are quantified.Results demonstrate that the effect of the power-law factor is relatively mild,as it does not significantly distort the parametric spaces.At the same time,there are quantitative differences,which are also determined by the obtained results.Numerical examples highlighting the effect of fracture regime on morphology of multiple fractures are presented at the end.
