Directions of the reservoir hydraulic fracture propagation and fluid flow are strongly dependent on the formation rode characteristics and the in-situ stress environment. Even though they are often considered as predetermined parameters, they can be modified in order to maximize the reservoir post-fracturing well performance. After reviewing some current techniques for determining the principal orientations of the in-situ fluid flow, this paper presents the correlation between the formation permeability and the associated stresses for the formations embedded with dominant orthogonal fractures in an arbitrary stress field. The two-dimensional examples are given to elicit the situation where a compromise between the conflicting optimal orientations for the hydraulic fracturing and for the fluid flow could be obtained.