Coalbed gas (CBG) is adsorbed, or attached, to the coal and kept in place by the pressure of the water in the coal seam. As water is pumped out, the pressure holding CBG to the coal is reduced. As a result the gas separates from the coal and flows up the well bore to the surface. Any water removed from the subsurface is referred to as "produced" water.

The two key determinants of a produced water management strategy are the composition and volume of produced water. Produced water from BC coalbed gas sites will range from fresh to saline, but composition and quantity must be confirmed through drilling and testing. Starting with the exploration phase, long before sizeable quantities of water are produced, the Oil and Gas Commission (OGC) requires produced water to be tested by a provincially accredited laboratory.

The OGC regulates all produced water and typically requires it to be re-injected deep into the earth. Companies must isolate the subsurface disposal areas from potential groundwater zones and prove that these disposal areas will contain the anticipated volumes of re-injected water. To protect drinking water from possible cross-contamination, all disposal wells are lined with steel casing that extends from the surface to the disposal formation. This casing is cemented into the well bore.

On February 27, 2007, the Provincial Government released “The BC Energy Plan: A Vision for Clean Energy Leadership”.  The Energy Plan clarifies and enhances British Columbia’s commitments to making British Columbia coalbed gas production the most environmentally responsible in North America.  By the new standards put forward in the Energy Plan, companies wanting to develop coalbed gas will not be allowed to surface discharge produced water.  Any re-injected produced water must be injected well below any domestic water aquifer.

Experience in the United States has shown that CBG produced water can be put to a number of beneficial uses.  While some of these innovative uses may be appropriate for CBG produced water in BC, the method of water disposal will be decided on a case-by-case basis after the specifics of a given site or CBG well have been analyzed and directly affected stakeholders consulted.

Following are links to technical resources on produced water:

Oil and Gas Waste Regulation

Bibliography on Water Handling, Environmental, and Land Use Aspects

In October 2001, the British Columbia Ministry of Energy and Mines contracted Western Ecological Services Ltd. to review the existing literature on water handling, environmental, and land-use aspects of coalbed gas (CBG) development. The review’s purpose was to provide background information for the Provincial Steering Committee and Working Group for CBG Development – Produced Water Disposal.

Additional references that were not keyword coded or annotated because they could not be obtained by the end of this review are listed in Attachment 3.

Attachment 1: Bibliography of CBG Environmental Reference (PDF 400.46KB)

Attachment 2: CBG References Sorted by Keyword Phrases (PDF 835.04KB)

Attachment 3: Additional Reference (PDF 85.88KB)

Selected Annotated References on Water Handling, Environmental, and Land Use (PDF 511.81KB)

The Selected Annotated References consists of 153 annotated references derived from the more comprehensive bibliography. The selection of references for annotation was based on their subject matter content. The references selected contained the most substantial information with an emphasis on concerns about CBG produced water and alternatives for handling the water.

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Last Updated May 17, 2007