Study of biofilms of sulfidogens from North Sea oil production facilities using continuous-flow apparatus

Sulfide-generating bacteria (sulfidogens) in oil reservoirs are of great economic importance in terms of corrosion, biofouling, and reservoir souring. Research attention has focused on corrosion and hydrogen sulfide production from sulfate-reducing bacteria attached to metal surfaces, with little emphasis on the reservoir environment itself: In this article we describe a new high temperature anaerobic continuous-flow apparatus to study biofilms of thermophilic sulfidogens attached to sand in a dynamic situation, parameters affecting the continuous growth and development of the biofilms may be controlled in this system, which is sampled nondestructively, offering a unique opportunity to predict the effect of oil reservoir management decisions. Development and use of the sand pod apparatus are described, with discussion of data relating to colonization of sand surfaces and dispersion into deeper zones of the sand column (new sites of bacterial attachment were established within 5 days of commencement of fluid flow). Biofilms starved of an organic carbon source for 3 days ceased sulfide generation and then resuscitated within a similar time frame when nutrients were restored producing further hydrogen sulfide. Longer term starvation of 14 days was also followed by further sulfide generation.