Optimization of fracture length and well spacing can be critical to the economics of the exploitation of natural gas resources. If the fracture length is small compared to well spacing, then fracture azimuth will not affect interference between wells; many fields will be drilled to dense spacings and therefore require knowledge of the fracture azimuth to optimize the number of wells, the placement of the wells, and the length of the fractures. This is contrary to historical approaches to the optimization of ultimate recovery and net present value from tight gas fields, which are based on the idealization of homogenous, isotropic reservoirs and which neglect interwell interference.

This paper reviews current technology for determining hydraulic fracture azimuth, and presents a solution for uniform flux fractures which accounts for fracture azimuth. It is shown that the uniform flux fracture model fails when interference between wells is significant. Numerical simulation of high conductivity fractures confirms that knowledge of fracture azimuth will be important for cases for which the ratio of interwell distance to fracture length is less than 2.0. Permeability anisotropies increase the importance of knowing fracture azimuth. A general procedure for optimization of fracture azimuth and well spacing is presented.

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