Isolation and Core Penetration of Starved and Vegetative Cultures from North Sea Oil Systems

Abstract

Isolation and Core Penetration of Starved and Vegetative Cultures from North Sea Oil Systems

Several cultures of bacteria were derived from field surveys of three separate production facilities in the North Sea; enrichment of 54 production water samples was designed to recover thermophilic sulphate-reducing bacteria (SRB). In spite of differences in reservoir production temperatures, geology and latitude, tSRB were recovered from all but one of the original samples. Examination of the cultures revealed that there was a wide variety of different bacteria selected by enrichment, all able to grow anaerobically at 60˚C, produce hydrogen sulphide and heavy precipitates of insoluble sulphides. Microscopic examination disclosed widely varied cell morphologies, confirming that there are many different tSRBs existing in production waters, some as tightly associated co-cultures. Samples of sea water collected both in the vicinity of the production facilities and from the open sea also yielded cultures of tSRB, indicating that the bacteria may be originally derived from either oil formations or injection sea water.