List of Model Input Variables

The following list of variables were needed as input for running CMG's GEM Reservoir Simulator. The GEM Simulator is a multi-component, multi-phase reservoir simulator that utilizes Equations of State (EOS) formulations. The software has numerous built-in features to account for many complex interactions that take place in a CBNG reservoir and ECBNG recovery.

Basic Reservoir Model Variables

Start Date
Grid Geometry
Gridtop
Grid Thickness
Porosity (Matrix, Fracture)
Permeability I, J, K (Matrix)

Permeability I, J, K (Fracture)

Fracture Spacing (I, J, K)

Rock Compressibility

Reference Pressure

Sw (matrix, fracture)

Well Location

Perforations

Well Constraints

CBNG Model Variables

Define Components

Water Viscosity

Reference Pressure for Water Density

Initial Reservoir Pressure

Reservoir Temperature

Max Gas Content

Langmuir Pressure

Initial Gas Content

Coal Desorption Time

Coal Diffusion Coefficent

Initial Gas Composition

Palmer and Mansoori Model Variables

Young's Modulus

Poisson's Ratio

Strain at Infinite Pressure

Palmer and Mansoori Exponent

Langmuir Isotherm

Gas storage capacity of a coal can be expressed by the above equation - a function of its Pressure (P), Langmuir volume constant (V_L), and Langmuir pressure constant (P_L). The maximum amount of sorbed gas in a coal is represented by the Langmuir volume constant. The Langmuir pressure constant is the pressure at which gas storage capacity equals half of the Langmuir volume constant. The (V_L) and (P_L) dictate the shape of the isotherm, which can be used to predict the amount of gas released as reservoir pressure is reduced.

http://www.kgs.ku.edu/PRS/publication/2006/2006-13/p3-02.html

Last Modified May 2006