HORIZONTAL WATERFLOOD SCHEDULED IN TEXAS CARBONATE RESERVOIR

Win Energy Inc., Midland, Tex., plans this fall to begin a project believed to be the first horizontal waterflood in the U.S. The company plans to waterflood a carbonate reservoir covering about 1,600 acres in West Central Texas. Win will drill as many as eight horizontal water injection wells along the downdip edge of the combined Bullard Unit/Propst-Anson fields in Jones County. The reservoir, Permian Flippen limestone at about 2,540 ft, is solution gas driven. The wells will have

Sept. 2, 1991

2 min read

Win Energy Inc., Midland, Tex., plans this fall to begin a project believed to be the first horizontal waterflood in the U.S.

The company plans to waterflood a carbonate reservoir covering about 1,600 acres in West Central Texas.

WHAT'S PLANNED

Win will drill as many as eight horizontal water injection wells along the downdip edge of the combined Bullard Unit/Propst-Anson fields in Jones County. The reservoir, Permian Flippen limestone at about 2,540 ft, is solution gas driven. The wells will have horizontal legs of about 1,500 ft.

The company also plans to recomplete several wells and drill several vertical production wells in a project that carries a total cost estimated at $4.5 million. It forecasts ultimate recovery of about 57% of the original oil in place (OOIP) as a result of the flood.

John D. Whiteside Jr., Win's executive vice-president, said spacing will be such that the wells virtually link up, creating a "line drive" of water.

Key to the project's effectiveness is the massive amount of water injected. Win plans an injection rate of 1 b/d/ft of horizontal displacement. Although that's about 1/10 the rate of a conventional water injector, it works out to about 1,500 b/d because of the greater displacement in the planned horizontal injection wells.

"The high volumes give it the water drive nature didn't give it," Whiteside said.

RAPID RECOVERY

Using horizontal injection wells allows the reservoir to take in large volumes of water over a large area without danger of overpressurizing, Win said. The result is rapid fill-up and accelerated recovery.

In addition, Win predicts incremental oil recovery will be greater with the improved sweep efficiency with a horizontal waterflood.

In its engineering evaluation, Win estimates primary production has recovered 32% of OOIP, pegged at more than 6 million bbl. it expects to produce an additional 1.5 million bbl of oil from the combined fields.

Bullard field was discovered in 1950, once had as many as 55 producing wells, and has produced more than 2 million bbl of oil. Propst-Anson field, a 1981 discovery, has produced about 200,000 bbl.

Win has submitted the project to the Department of Energy for possible funding assistance. Whiteside said several independent producers are evaluating the project as possible participants.