Overview of Souring, Corrosion and Plugging Due to Reservoir Organisms

Abstract

Overview of Souring, Corrosion and Plugging Due to Reservoir Organisms

Recent advances in the study of sub-surface microbiology have revealed the presence of a diverse microflora, in deep, hot, saline rock. These bacteria may be indigenous to the rock but they may be introduced by groundwater movement or due to oilfield exploration activities.

The most of the down-hole microbial problems derive from seawater injection, although drilling operations also serve as a source of problem-causing bacteria. Water injection may further encourage microbial activity by introducing fresh sources of bacterial nutrients (both organic and inorganic) or by changing the physico-chemical environment (pH, Eh).

Bacterial presence and activity may lead to three major consequences with respect to oil extraction and production, namely:

• Plugging of reservoir rock pore spaces and loss of water injectivity.
• Hydrogen sulphide (H2S) souring of fluids, with safety and corrosion implications.
• Corrosion of downhole and topside materials (MIC).
• This paper sets out to highlight the involvement of the reservoir microflora in problems associated with the oil industry.

This paper sets out to highlight the involvement of the reservoir microflora in problems associated with the oil industry.