Fate of organics spent drilling fluid discharged into the marine environment. Final report.

Abstract

The potential impact of spent drilling fluids that result from operations in the vicinity of the Texas Flower Gardens Reef system has aroused concern over the fate and effects of components discharged to the marine environment. These unique reefs are situated atop salt domes which are known to harbor gas and oil reserves and are located in the Gulf of Mexico about 200 km south, southeast of Galveston, Texas on the outer continental shelf. To better understand the fate of the organic constituents a 27,000 liter surface discharge of drilling fluid was monitored from an operating oil rig approximately 50 miles to the northeast of the reefs in the Gulf of Mexico during June, 1980. Sediment, suspended particles, and water samples were collected near the rig during and after the discharge. Background data were obtained by collecting samples from the Flower Gardens Coral Reef area and from the production rig areas to the north and northeast of the reef. Organic constituents in spent drilling fluid were investigated to determine those most useful as tracers for dispersion in seawater. The most likely tracers were ferrochrome lignosulfonate (FCLS) and petroleum hydrocarbons. FCLS readily dissolved when dispersed in seawater, whereas the petroleum was primarily associated with the particulate fraction.