Rex Energy Corp., State College, Pa., said its enhanced oil recovery operations in giant Lawrence field in southern Illinois have the potential to double the field’s output by the end of 2015.
Lawrence field had an estimated 1 billion bbl of original oil in place, of which 400 million bbl have been recovered since 1906. Waterflooding started in the 1950s, and Marathon Oil Corp. recovered 15-20% of OOIP at two surfactant-polymer floods in the 1970s-80s.
The field’s primary producing zones are the Mississippian Cypress and Pennsylvanian Bridgeport sandstones.
Rex commenced alkali-surfactant polymer flooding on the 58-acre Perkins-Smith pilot in June 2012 and expects initial response by the second quarter of 2013 and peak response in the 2013 fourth quarter.
Rex said in March 2012 that it believes it is the only company in the US to have successfully applied this specific ASP technology and that its goal is to duplicate the oil recovery performance of the 1980s surfactant-polymer floods.
Core flood work continues on the 351-acre Delta Unit as additional pattern wells are being drilled, and the company expects to be able to book proved reserves for the Delta Unit commercial expansion as early as the end of 2012.
Full-scale ASP injection is to start in the Delta Unit in the second quarter of 2013. Initial response is expected in 2014, and peak response at an estimated 13% of pore volume recovery is expected in mid-2015 at around 1,000 b/d.
Oil production averaged 50 b/d at the 15-acre Middagh pilot in the quarter ended June 30 compared with a peak of more than 100 b/d in September 2011. The pilot continues to support the 2011 yearend proved reserves booking of 13% of pore volume recovery, the company said.
Rex said Middagh oil cuts have risen to 12% from 1% in the total unit and that individual wells have experienced oil cuts above 20%.