Development of Coal Gas Production Simulators and Mathematical Models for Well Test Strategies (Computer Model for an Array of Vertical Wells and Overview of Contract Results)

摘要

A computer program, designated ARRAY and written in a structured dialect of FORTRAN, has been developed to simulate the transient, two-dimensional (areal) two-phase flow of methane gas and water through a coal seam to an array of vertical wells. The coal seam is modelled as a dual porosity medium which incorporates time-dependent, non-linear sorption of methane on internal surfaces of the coal matrix. A number of flow phenomena can optionally be included in the model such as non-laminar flow, gas slippage, coal seam compressibility, stress-sensitive permeability, and stratified flow. This is the third in a series of computer models for production of methane from coal seams. Models WELL1D - for production by an isolated, unstimulated vertical well or by an isolated vertical well connected to an induced, high conductivity (constant pressure) vertical fracture - and WELL2D - for production by an isolated vertical well connected with an induced, finite-conductivity vertical fracture - were presented previously in an Annual and a Topical Report for this contract. An extensive bibliography derived from a computer-assisted search of the technical literature also was presented in the Annual Report.