Numerical simulation of the transient behavior of coal seam degasification wells

Conference · Tue Nov 01 04:00:00 EST 1983 · Soc. Pet. Eng. AIME, Pap.; (United States)

OSTI ID:5369312

King, G R; Ertekin, T; Schwerer, F C

Described in this paper are the mathematical and numerical developments for a series of finite difference models which simulate the two-phase, transient behavior of coal seam degasification wells. Included in this series are models for unstimulated, as well as hydraulically stimulated, wells. The hydraulically stimulated wells are assumed to have either a single infinite or finite conductivity vertical fracture. The natural fracture system of the coal seam, the butt and face cleat, is identified with a porous network and assigned effective porosities, nominally less than ten percent, and absolute permeabilities, generally less than 25 md with values extending into the microdarcy range. A time dependent sorption term has been included to describe the phenomenon of gas desorbing from the coal matrix to the porous network. The coal seam is then modeled with the mathematics of multiphase flow through porous media. All models described in this paper are single well, mesh centered models in radial-cylindrical coordinate geometry. The fully implicit, generalized Newton-Raphson procedure has been employed to solve the coupled, nonlinear equations generated by the models. An intensive sensitivity analysis of the models is included. All models have been verified with successful history matches against stimulated and unstimulated methane drainage wells producing from coal gas reservoirs.

• Research Organization: Pennsylvania State Univ.
• OSTI ID: 5369312
• Report Number(s): CONF-831190-
• Conference Information: Journal Name: Soc. Pet. Eng. AIME, Pap.; (United States) Journal Volume: SPE 11258
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
012000* -- Coal
Lignite
& Peat-- Mining
03 NATURAL GAS
030900 -- Natural Gas-- Artificial Stimulation
Plowshare-- (-1989)
ALKANES
COAL DEPOSITS
COAL MINES
COAL SEAMS
DARCY LAW
DEGASSING
DESORPTION
FINITE DIFFERENCE METHOD
FLOW MODELS
FLUID FLOW
GAS FLOW
GEOLOGIC DEPOSITS
HYDROCARBONS
INJECTION WELLS
ITERATIVE METHODS
LAMINAR FLOW
MATHEMATICAL MODELS
METHANE
MINERAL RESOURCES
MINES
MULTIPHASE FLOW
NEWTON METHOD
NUMERICAL SOLUTION
ORGANIC COMPOUNDS
RESOURCES
SIMULATION
SORPTION
UNDERGROUND FACILITIES
WELLS