The microbiology of drill mud cuttings from a new off-shore oilfield in Nigeria.

Drilling-fluid-utilising microorganisms present in drill mud cuttings collected from the Agbara oilfield were isolated on mineral salts agar plates. Thirty-two isolates were obtained, 26 of which were Gram-positive bacteria and six fungi. The isolates were identified as Bacillus sp. (10), Staphylococcus sp. (12), Micrococcus sp. (2), Corynebacterium sp. (1), Nocardia sp. (1), and Penicillium sp. (6). Screen tests indicated that 27 (84.4%) of the isolates did not grow with any of the drilling fluids One Bacillus and three Staphylococcus spp. were strong primary utilisers of the drilling fluids.