DOE says novel water cleaning technology could lessen environmental impacts from shale gas production
A novel water cleaning technology currently being tested in field demonstrations could help significantly reduce potential environmental impacts from producing natural gas from the Marcellus shale and other geologic formations, according to the Department of Energy’s (DOE) National Energy Technology Laboratory (NETL).
ABSMaterial’s Osorb technology, which uses swelling glass to remove impurities, has been shown to clean flow-back water and produced water from hydraulically fractured oil and gas wells. Produced waters are by far the largest volume byproduct associated with oil and gas exploration and production. Approximately 21 billion barrels of produced water, containing a wide variety of hydrocarbons and other chemicals, are generated each year in the United States from nearly one million wells.
Two pilot-scale Osorb-based water treatment systems have been built to date: a non-regenerating skid-mounted system which handles inputs of up to 4 gallons per minute, and a 60-gallon-per-minute trailer-mounted system that included a mechanism for Osorb regeneration. ABSMaterials has used these systems on numerous water samples including flow back water from the Marcellus, Woodford, and Haynesville shale formations and produced water from the Clinton and Bakken formations.
In independent testing, the skid-mounted system was found to remove more than 99% of oil and grease, more than 90% of dissolved BTEX (benzene, toluene, ethylbenzene, and xylenes), and significant amounts of production chemicals. Concurrent testing was performed using the trailer-mounted 60-gallon-per-minute system on produced water streams. One major oil services company conducted a full pilot test in the field using produced water from the Clinton formation in Ohio in July 2010 and March 2011. These tests showed that total petroleum hydrocarbon levels were slashed from 227 milligrams per liter to 0.1 milligrams per liter.
The results of this project have led to commercial interest from several global energy companies and future collaborative efforts. ABSMaterials also plans to deploy a trailer-mounted, 72,000-gallons-per-day water purification system for field use in North America in mid 2011.
A number of existing treatment techniques separate dispersed oils from water, taking advantage of the density difference between oil and water. However, very few technologies effectively address dissolved hydrocarbons, slicking agents, and polymers that prevent flow-back water from being recycled or discharged.
Osorb rapidly swells up to eight times its dried volume upon exposure to non-polar liquids. The swelling process is completely reversible—with no loss in swelling behavior even after repeated use—when absorbed species are evaporated by heating the material.
The ABSMaterials project was funded through the federal government’s Small Business Innovation Research Program. It is the second project under FE’s Oil and Natural Gas Program to show significant success treating produced or flow-back water. Several other projects will be conducting demonstrations focusing on other water treatment technologies during the remainder of fiscal year 2011.