Effects of drilling fluids on benthic communities at the lower Cook Inlet C.O.S.T. well

Abstract

From the Abstract: “Comprehensive field, laboratory and modeling studies were conducted to evaluate physical and biological effects of drilling effluent dischages from an offshore test well in Lower Cook Inlet, Alaska. The primary objectives of these studies were to evaluate the dispersion of drilling effluents and cuttings in the receiving waters, and to determine the impact of the dischages on commercially and ecologically important Alaskan species and on local benthic communities.

The benthic community in the vicinity of the drilling site was sampled before, during, and after the drilling operation. The fauna was typical of that found on relatively shallow dynamic sandy bottoms of northern subarctic regions and included several species common on sandy beaches in lower Cook Inlet. Some changes in benthic communities were seen near the drilling vessel during the course of the study. However, no statistically significant differences could be attributed to the effects of drilling operation because of patchiness in faunal distributions, probably due to differences in successional stages between areas sample. It appears that rates of accumulation from drilling muds and cuttings on the bottom in a dynamic environment such as found at the well site are not great enough to measurably affect benthic populations.”