CBM Water-Gas Ratio (WGR) & Dewatering Calculator

Model the 3-stage lifecycle production profile of coalbed methane wells: initial dewatering (100% water), peak gas breakout, and long-term depletion.

Production Stage & Reservoir Inputs

Initial Water Inflow Q_w0 (bbl/day):

Months on Production t (months):

Expected Peak Gas Rate Q_g,peak (Mscf/day):

Months to Peak Gas t_peak (months):

Water Decline Rate D_w (%/yr):

Gas Post-Peak Decline D_g (%/yr):

Production Rates & Water-Gas Ratio

Current Gas Rate Q_g:

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Current Water Rate Q_w:

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Water-Gas Ratio (WGR):

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Gas-Water Ratio (GWR):

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Current CBM Lifecycle Stage:

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Cumulative Water Produced:

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Frequently Asked Questions

What is a typical Water-Gas Ratio (WGR) for a mature CBM well?

Mature CBM wells typically produce between 10 and 50 barrels of water per million standard cubic feet (MMscf) of gas. In contrast, newly completed dewatering wells often produce over 1,000 bbl/MMscf.

Why are CBM operating costs heavily driven by water disposal?

During the first 6 to 18 months, disposing of produced formation water (via deep injection wells, evaporation ponds, or RO treatment) accounts for up to 80% of total lease operating expense (LOE).