Mobile nitrogen rejection unit takes the field

Dec. 16, 2010
EQT Corp., Pittsburgh, has placed in service the world’s first mobile nitrogen rejection unit for nitrogen frac flowback at a Devonian Huron shale well in eastern Kentucky.

By OGJ editors
HOUSTON, Dec. 16
– EQT Corp., Pittsburgh, has placed in service the world’s first mobile nitrogen rejection unit for nitrogen frac flowback at a Devonian Huron shale well in eastern Kentucky.

Developed by private IACX Energy, Dallas, the unit covers 158 ft by 38 ft on five trailers at the wellsite and employs nitrogen sponge technology.

In eastern Kentucky, the lower-pressured Huron shale has responded especially well to nitrogen fracturing treatment, but large volumes must be flowed back and vented until the hydrocarbon gas reaches pipeline quality. The clean-up period can last as long as 2 months, depending on reservoir quality.

Nitrogen frac flow-back applications are especially challenging because of the ever-changing composition of the gas entering the system. After a nitrogen frac, the percentage of nitrogen in the gross gas stream follows a steep gradient downward until most or all of the injected nitrogen is blown back.

The mobile iron sponge units yield 99+% recoveries of C3+ hydrocarbons, which contributes significantly to project economics where natural gas liquids are extracted and sold. All of the unit’s processes function at lower volumes and pressures and do not utilize chemicals or other environmentally undesirable materials, IACX noted.