Natural gas producers have a new tool in recycling untreated water that results from the hydraulic fracturing process at the well site. GE, Trevose, Pa., has introduced a mobile evaporator designed specifically for the process that extracts natural gas and oil buried deep below the earth's surface in shale reservoirs, which lack the natural permeability to flow to the surface for recovery.
The completely mobilized evaporator is energy efficient, fully transportable, cost effective and will enable onsite frac water recycling to reduce the volume of wastewater and fresh water hauled to and from the site.
The process of hydraulic fracturing, which involves creating small fractures in the rock surrounding the reservoirs in order to create a path through which the natural gas and oil can flow, has enabled production from oil and gas resources that were otherwise thought unrecoverable.
While hydraulic fracturing increases the production rate of oil and gas wells, the process also uses a substantial amount of freshwater and produces billions of gallons of wastewater each year. To offset this impact on the environment, GE's mobile evaporator treats the severely impaired waters, such as frac flowback and produced water, making it possible to reuse the water in the industrial process, reduce the amount of fresh water consumed and reduce any subsequent environmental impact from discharge.
The mobile evaporator is a horizontal 50 gal/min shell-and-tube, forced-circulation, mechanical vapor-recompression system. Unlike other treatment methods, thermal evaporation removes nearly all the impurities from the untreated water, allowing producers to meet Pennsylvania's discharge regulations. The unit mounts on a single trailer that allows it to reach remote drilling sites.
GE has offered thermal evaporation technology for more than 40 years, but this is the first time that the technology has been completely mobilized for use in the treatment of shale-gas frac water. The evaporator can be used for all unconventional gas and frac water applications in regions of the world where shale gas can be found, including North America, Europe, China and Indonesia. Initial applications will be in various North American markets such as the Marcellus Shale reservoirs located in the Appalachian Basin.
Regions like the Marcellus Shale are unique in that they produce very high total dissolved-solids frac water, and have limited deep-well capacity and increasingly stringent discharge regulations. The mobile evaporator will enable natural gas producers to significantly decrease their transportation and disposal costs. Additionally, the communities would benefit from less truck traffic and decreased wear and tear on local roads. The first units will be available in early 2011.