| This thesis investigates the flow of compressible fluids in pneumatically fractured formations.;A flow model for discrete fractures is derived based on the assumptions of viscous, laminar fluid flow through planar fractures. The model takes into account non-linearity introduced by gas compressibility effects. Provision is made for turbulent conditions which can result from high flow velocity and/or surface roughness of fractures.;Model validation is accomplished by analyzing pressure and flow data from a siltstone formation which had been pneumatically fractured in the vadose zone. Analysis of fracture flow velocities and associated Reynolds numbers indicated that although laminar flow conditions exist in natural fracture networks, some degree of turbulence may be encountered in pneumatically induced fractures owing to aperture enlargement.;Detailed study of borehole video tapes of the fracture well indicated the principal mechanism of flow enhancement was aperture dilation of existing natural fractures, and improvement of fracture connectivity. A minor amount of new horizontal and vertical fractures were noted. Statistical analysis of the video indicated an improvement in flow uniformity along the borehole profile, as a result of fracturing. A physical model of the fracture zone is presented. (Abstract shortened by UMI.). |
