CBM Critical Desorption Pressure & Dewatering Calculator

Calculate the critical desorption pressure and required liquid hydrostatic drawdown (ft) needed to initiate first gas breakout in undersaturated coal seams.

Well & Seam Reservoir Data

Coal Seam Midpoint TVD (ft):

Initial Reservoir Pressure P_i (psi):

Canister Gas Content G_c (scf/ton):

Langmuir Volume V_L (scf/ton):

Langmuir Pressure P_L (psi):

Produced Water Gradient (psi/ft):

Dewatering Head & Breakout Targets

Critical Desorption Pressure P_cd:

—

Required Pressure Drawdown:

—

Target Dynamic Fluid Level (DFL):

—

Maximum Water Column Over Seam:

—

Initial Water Head Over Seam:

—

Dewatering Fluid Level Drop:

—

Recommended Tools & Equipment

Tested hardware and components for high reliability

100% Free Tool Zero Sign-Up

Frequently Asked Questions

Why should operators avoid drawing down a CBM well too quickly?

Pumping a CBM well down too aggressively can cause high pressure drops that trigger coal fines spalling, cleat collapse, and coal face crushing. Controlled, continuous dewatering preserves cleat permeability and avoids plugging downhole rod pumps or PCPs.

What type of artificial lift is standard for CBM dewatering?

Progressive Cavity Pumps (PCPs) and beam pumping units (sucker rod pumps) are standard because they handle abrasive coal fines and pump steady low-to-moderate water volumes (50 to 500 bbl/day) without gas locking.