Sorption Compressibility

Introduction

Sorption of gas on coal or shale results in a highly compressible reservoir/fluid system. Sorption compressibility is given by:

Where:

B_g = Gas Formation Volume Factor, Dim

rho = coal bulk density, g/cm3

V_L = Langmuir Volume AR, scf/ton

P_L = Langmuir Pressure, psia

c_s = Sorption Compressibility, psia-1

Depending on the context, it may also be called Desorption Compressibility.

This variable is encountered often in scenarios where there may be absorbed gas such as Coal Seam Gas (CSG) and/or Tight Gas and Shale