Reservoir EngineeringUnconventional Reservoirs
Coalbed Methane Formation Compressibility Formula
Coalbed Methane Formation Compressibility calculates total compressibility for unconventional reservoirs workflows in reservoir engineering.
How engineers use this formula
Use this formula when the listed inputs (W_i, W_p, P_i, P_d) are known and the assumptions behind the cited unconventional reservoirs relationship match the engineering case being checked.
Assumptions
- Input values are representative for the well, reservoir, fluid, or equipment case being evaluated.
- The declared units match the field-unit constants used in the formula.
- The cited formula applies to the selected petroleum engineering workflow.
Limitations
- The calculation does not replace a full engineering model or operating procedure.
- Accuracy depends on the source correlation, assumptions, input quality, and unit consistency.
Common mistakes
- Mixing unit systems without converting the inputs.
- Using default example values as field recommendations.
- Applying the formula outside the source assumptions.
Default example
Using the default inputs, c_t equals 0.00025 1/psi.
W_ibbl
1000000
W_pbbl
100000
P_ipsi
1200
P_dpsi
800
Inputs
W_i
bblInitial Water Volume in Reservoir
W_p
bblWater Volume Removed
P_i
psiInitial Reservoir Pressure
P_d
psiDesorption Pressure
Outputs
c_t
1/psi
Total Compressibility
W_i
bbl
Initial Water Volume in Reservoir
W_p
bbl
Water Volume Removed
P_i
psi
Initial Reservoir Pressure
P_d
psi
Desorption Pressure
Source and review
reviewedAhmed, T., McKinney, P.D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter 3, Page 219.
Source