DEVELOPING PRODUCED WATER MANAGEMENT STRATEGIES FOR COALBED METHANE OPERATIONS IN THE BLACK WARRIOR BASIN

摘要

Natural gas is stored in coal primarily in an adsorbed state, and large volumes of formation water need to be produced to depressurize coal, thereby releasing the adsorbed gas for commercial production. For this reason, management of produced water is one of the most critical issues facing the coalbed methane (CBM) industry (e.g., Pashin et al., 1991; Ayers and Kaiser, 1994; van Voast, 2003; Pashin, 2007). The Black Warrior basin of Alabama (fig. 1) is a mature province where CBM producers face a range of water management issues. In the eastern CBM fields, fresh water has been disposed safely in streams for decades. Even so, this practice is a subject of increasing scrutiny by environmental groups and agencies, and some of the produced water may have beneficial agricultural and industrial uses. In the western fields, where significant potential exists for expansion of the CBM industry, saline formation water limits the ability of producers to pump wells to depressurize coal, which in turn leads to underperforming gas production (Pashin, 2008a).