Fractional gas recovery below the critical desorption pressure in coal bed methane reservoirs

Input(s)

$\mathrm{V}_{\mathrm{m}}$: Langmuir (constant)

$\mathrm{G}_{\mathrm{c}}$: Gas Content at Critical Desorption Pressure (SCF/ton)

b: Langmuir (constant)

P: Pressure of Reservoir (psi)

a: Recovery Exponent (dimensionless)

Output(s)

RF: Recovery Factor (fraction)

Formula(s)

$$ \mathrm{RF}=1-\left(\left(\frac{\mathrm{V}_{\mathrm{m}}}{\mathrm{G}_{\mathrm{c}}}\right) *\left(\frac{\mathrm{b} * \mathrm{P}}{1+\mathrm{b} * \mathrm{P}}\right)\right)^{\mathrm{a}} $$

Reference(s)

Ahmed, T., McKinney, P.D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter: 3, Page: 223 .