SCHRAMM, WILLIAM H. and GARY A. FULTON Jr.
Louisiana Department of Environmental Quality, Baton Rouge, LA

Abstract: Environmental Impact of the Freshwater Wilcox Aquifer by a Gas Well Blowout in Northwest Louisiana

The Louisiana Department of Environmental Quality, Ground Water Protection Division (GWPD) is responsible for oversight of the investigation and remediation of unpermitted releases to the groundwater of the State. During the drilling of a Sligo Field gas well a blowout induced artificial artesian conditions in the shallow Wilcox aquifer resulting in flowing water wells near the drilling location. The gas charged waters erupted around an old abandoned well south of the active rig, spewing sand and water. The removal of sand from the aquifer caused a collapse crater north of the rig.

The company, in cooperation with the GWPD, began an investigation of the environmental impacts of the blowout. Geotechnical borings, electric logs and monitor wells were used to determine the stratigraphy and to assess the extent of contamination in the aquifer. Monitor wells and nearby water supply wells were sampled for BETX. Wells nearest the blowout showed constituents above regulatory limits while wells positioned between the blowout and residential wells were unimpacted

This presentation will describe the continuing investigation and corrective actions planned for this site. These actions may include: additional wells or borings to delineate and monitor the area impacted by the blowout, evaluation of pump and treat methods to establish hydrologic control of the Wilcox Aquifer in the immediate area and evaluation of risk to the residential population. Periodic testing of the private and monitor wells will ensure that appropriate efforts are made to protect the residents.

AAPG Search and Discovery Article #90928©1999 AAPG Annual Convention, San Antonio, Texas