Overview

A well is drilled to produce coalbed natural gas. Within the coal seam, the natural gas is held in place by water pressure. In order to release the natural gas, drillers must lower the hydrostatic pressure enough to depressurize the coal.

Coalbed natural gas wells go through three stages during their productions cycles. During the initial de-pressuring stage, the water is produced with little or no gas. However, over time, the volume of water continues to decrease while the volume of natural gas produced increases. A stable production stage is reached when the maximum amount of natural gas is being produced and the water production continues to decrease.

Management Options

The water produced by CBNG development will be sent to agreed-upon management sites on the property within regulatory guidelines. Most water may be discharged into drainages including off-channel reservoirs, in-channel ponds and stock tanks.

An in-channel drainage refers to an established drainage whereas off-channel is created to hold produced water. The types, locations and sizes of these reservoirs and ponds are generally included in the surface owner agreement and determined by what works best for the landowner’s use within regulatory guidelines.

Depending on the soils and the quality of the produced water, the reservoir may be lined with plastic or clay plating to prevent seepage into the ground. It may be necessary to properly identify appropriate soil types and adding soil or water amendments if the produced water will be used for irrigation purposes. The addition of gypsum (a form of calcium) and sulfur is currently being practiced with much success.