We developed an anisotropic effective theoretical model for modeling the elastic behavior of anisotropic carbonate reservoirs by combining the anisotropic self-consistent approximation and differential effective mediu...We developed an anisotropic effective theoretical model for modeling the elastic behavior of anisotropic carbonate reservoirs by combining the anisotropic self-consistent approximation and differential effective medium models.By analyzing the measured data from carbonate samples in the TL area,a carbonate pore-structure model for estimating the elastic parameters of carbonate rocks is proposed,which is a prerequisite in the analysis of carbonate reservoirs.A workflow for determining elastic properties of carbonate reservoirs is established in terms of the anisotropic effective theoretical model and the pore-structure model.We performed numerical experiments and compared the theoretical prediction and measured data.The result of the comparison suggests that the proposed anisotropic effective theoretical model can account for the relation between velocity and porosity in carbonate reservoirs.The model forms the basis for developing new tools for predicting and evaluating the properties of carbonate reservoirs.展开更多
Numerous experimental studies reveal that the mechanical and deformational behaviors of sands are dependent on the combined effect of void ratio and stress. To predict this complex behavior of sands, a hypo-elastic mo...Numerous experimental studies reveal that the mechanical and deformational behaviors of sands are dependent on the combined effect of void ratio and stress. To predict this complex behavior of sands, a hypo-elastic model is developed based on the cross-anisotropic elasticity model, which involves four parameters: bulk module, tangent Young's module, volume deformation coefficient and Poisson ratio. A parameter defined as virtual peak deviatoric stress dependent on state parameter is introduced into hyperbolic stress strain relationship to determine tangent Young's module. In addition, an existing fitting equation for isotropic compression curves and an existing dilatancy equation, which can consider the effect of state of sands, are employed to determine bulk module and volume deformation coefficient. Thirteen model constants are involved in the proposed model, the values of which are fixed for a sand over a wide range of initial void ratios and initial confining pressures. Well known experimental data for drained and undrained triaxial compression tests of Toyoura sand are successfully modeled.展开更多
Seismic anisotropy is a relatively common seismic wave phenomenon in laminated sedimentary rocks such as shale and it can be used to investigate mechanical properties of such rocks and other geological materials. Youn...Seismic anisotropy is a relatively common seismic wave phenomenon in laminated sedimentary rocks such as shale and it can be used to investigate mechanical properties of such rocks and other geological materials. Young's modulus and Poisson's ratio are the most common mechanical properties determined in various rock engineering practices. Approximate and explicit equations are proposed for determining Young's modulus and Poisson's ratio in anisotropic rocks, in which the symmetry plane and symmetry axis of the anisotropy are derived from the constitutive equation of transversely isotropic rock. These equations are based on the media decomposition principle and seismic wave perturbation theory and their accuracy is tested on two sets of laboratory data. A strong correlation is found for Young's modulus in two principal directions and for Poisson's ratio along the symmetry plane. Further, there is an underprediction of Poisson's ratio along the symmetry axis, although the overall behavior follows the trend of the measured data. Tests on a real dataset show that it is necessary to account for anisotropy when characterizing rock mechanical properties of shale. The approximate equations can effectively estimate anisotropic Young's modulus and Poisson's ratio, both of which are critical rock mechanical data input for hydraulic fracturing engineering.展开更多
基金supported by the National Natural Science Foundation of China(No.41274136)
文摘We developed an anisotropic effective theoretical model for modeling the elastic behavior of anisotropic carbonate reservoirs by combining the anisotropic self-consistent approximation and differential effective medium models.By analyzing the measured data from carbonate samples in the TL area,a carbonate pore-structure model for estimating the elastic parameters of carbonate rocks is proposed,which is a prerequisite in the analysis of carbonate reservoirs.A workflow for determining elastic properties of carbonate reservoirs is established in terms of the anisotropic effective theoretical model and the pore-structure model.We performed numerical experiments and compared the theoretical prediction and measured data.The result of the comparison suggests that the proposed anisotropic effective theoretical model can account for the relation between velocity and porosity in carbonate reservoirs.The model forms the basis for developing new tools for predicting and evaluating the properties of carbonate reservoirs.
基金Project(2010BC732101)supported by the National Basic Research Program of China
文摘Numerous experimental studies reveal that the mechanical and deformational behaviors of sands are dependent on the combined effect of void ratio and stress. To predict this complex behavior of sands, a hypo-elastic model is developed based on the cross-anisotropic elasticity model, which involves four parameters: bulk module, tangent Young's module, volume deformation coefficient and Poisson ratio. A parameter defined as virtual peak deviatoric stress dependent on state parameter is introduced into hyperbolic stress strain relationship to determine tangent Young's module. In addition, an existing fitting equation for isotropic compression curves and an existing dilatancy equation, which can consider the effect of state of sands, are employed to determine bulk module and volume deformation coefficient. Thirteen model constants are involved in the proposed model, the values of which are fixed for a sand over a wide range of initial void ratios and initial confining pressures. Well known experimental data for drained and undrained triaxial compression tests of Toyoura sand are successfully modeled.
基金supported by the National Science and Technology Major Project of China (Grant No. 2016ZX05024001-008)
文摘Seismic anisotropy is a relatively common seismic wave phenomenon in laminated sedimentary rocks such as shale and it can be used to investigate mechanical properties of such rocks and other geological materials. Young's modulus and Poisson's ratio are the most common mechanical properties determined in various rock engineering practices. Approximate and explicit equations are proposed for determining Young's modulus and Poisson's ratio in anisotropic rocks, in which the symmetry plane and symmetry axis of the anisotropy are derived from the constitutive equation of transversely isotropic rock. These equations are based on the media decomposition principle and seismic wave perturbation theory and their accuracy is tested on two sets of laboratory data. A strong correlation is found for Young's modulus in two principal directions and for Poisson's ratio along the symmetry plane. Further, there is an underprediction of Poisson's ratio along the symmetry axis, although the overall behavior follows the trend of the measured data. Tests on a real dataset show that it is necessary to account for anisotropy when characterizing rock mechanical properties of shale. The approximate equations can effectively estimate anisotropic Young's modulus and Poisson's ratio, both of which are critical rock mechanical data input for hydraulic fracturing engineering.
