Numerical simulation of the transient behavior of coal seam degasification wells

Conference · Tue Nov 01 00:00:00 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-
• Journal Information: Soc. Pet. Eng. AIME, Pap.; (United States), Vol. SPE 11258; Conference: 7. Society of Petroleum Engineers reservoir simulation symposium, San Francisco, CA, USA, 15 Nov 1983
• Country of Publication: United States
• Language: English

Related Subjects

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