E-Book Overview
The ubiquitous examples of unsteady-state fluid flow pertain to the production or depletion of oil and gas reservoirs. After introductory information about petroleum-bearing formations and fields, reservoirs, and geologic codes, empirical methods for correlating and predicting unsteady-state behavior are presented. This is followed by a more theoretical presentation based on the classical partial differential equations for flow through porous media.Whereas these equations can be simplified for the flow of (compressible) fluids, and idealized solutions exist in terms of Fourier series for linear flow and Bessel functions for radial flow, the flow of compressible gases requires computer solutions, read approximations. An analysis of computer solutions indicates, fortuitously, that the unsteady-state behavior can be reproduced by steady-state density or pressure profiles at successive times. This will demark draw down and the transition to long-term depletion for reservoirs with closed outer boundaries.
E-Book Content
Unsteady-State Fluid Flow: Analysis and Applications to Petroleum Reservoir Behavior by E. J. Hoffman
• ISBN: 0444501843 • Publisher: Elsevier Science & Technology Books • Pub. Date: August 1999
PREFACE The partial differential equations for the unsteady-state flow of compressible fluids through porous media are deceptively simple in their statement. Their solution to yield pressure and density in terms of position and time, and subject to the requisite boundary conditions, is another matter entirely. In the case of compressible liquids, the compressibility behavior may be so represented that the differential equations become analogous to those for heat conduction. And for this circumstance there are purportedly analytical solutions for either linear flow or radial flow, subject to one or another of several different combinations of boundary con