CBM development differs from conventional gas production in two key ways:
1. It requires the wells be closer together. Conventional - one well per 640 acres: CBM one well per 80 acres or even as low as 40 acres. This means more intensive land impacts with more roads, pipe & power lines, compressors, etc. Current BC law does not set a limit on spacing of CBM wells.
2. CBM is held in coal seams by large quantities of water which must be pumped out to release the gas. This water can be saline and may contain heavy metals. Surface discharge may be damaging to both surface vegetation and water quality.Our geology may prevent re-injection. Encana is using surface discharge up the valley.