Treatment Technologies for Coalbed Methane Produced Water Management
One of the major economic constraints to increasing natural gas production in the Rocky Mountain and Mid-Continent regions of the U.S. is the cost-effective management and disposal of co-produced water. Some of the greatest challenges exist in the coalbed methane (CBM) basins where the existing reinjection well capacities are not sufficient to dispose of growing volumes of produced water. Alternatives to reinjection include treatment of produced water streams to meet criteria for surface discharge, infiltration and beneficial reuse with brine volume reductions sufficient to extend the life of existing Class II reinjection wells. Over the past decade, a number of commercial and advanced technologies have been developed and deployed for the handling of produced waters. In addition, research and development is being conducted on process strategies that are aimed at converting produced water to beneficial-use water supplies. The challenge is to achieve the required levels of treatment while avoiding the equipment-fouling reliability problems commonly observed with conventional membrane-based treatment systems. This presentation will provide an overview of emerging processes that have the potential of improving the economics of treating produced waters to meet objectives of brine volume reduction, surface water discharge, infiltration for groundwater recharge and beneficial use. Some major technical challenges include the control of soluble and free oils, the fouling of membrane-based desalinization processes, the control of elevated levels of precipitates and soluble volatile acids, and the economical control of BTEX. Promising processing approaches to improve the economics of reaching beneficial-use water management objectives will be discussed.