CONCLUSIONS

We find that the Sayers and Kachanov (1991) crack-influence parameters are ideally suited to analyzing the role of fracture mechanics in producing anisotropic elastic constants for aligned fractures in a reservoir exhibiting HTI symmetry. Discussion of the results obtained for the higher crack density examples presented in Figures 1-6 will be provided in a later publication. But the main ideas are already contained in Berryman and Grechka (2006) and Berryman (2007). One important conclusion from the modeling presented here is that the Thomsen weak anisotropy method is valid for crack densities up to about $\rho_c \simeq 0.05$, but should be replaced by better approximations, or exact calculations, if the crack density is $\rho_c \simeq 0.1$ or higher.