Abstract
The candidate waters available for secondary recovery of oil in West Kuwait oil fields are all high in salt. Total dissolved solids (TDS) of an aquifer water is 239,000 ppm (chloride, 146,000 ppm). Effluent water varies, but TDS can reach 241,000 ppm (chloride, 151,000 ppm). Candidate materials for tubulars for secondary injection were tested for MIC attack at high salt concentrations. N-80 and L-80 steels, and three FRPs - phenolic, vinyl ester and epoxy resin were tested in the two water types. A mixed bacterial consortium (including SRB) from a natural Mediterranean marine environment was habituated to high salinity and used as the inoculum.
All steel coupons were attacked. Ranking from most to least corroded was as follows: L-80 effluent water > L-80 aquifer water > N-80 effluent water > N-80 aquifer water, indicating that N-80 was more corrosion resistant than L-80 and effluent water was more corrosive than aquifer in these experiments.
There was no evidence of attack of the vinyl ester or epoxy based FRP coupons by microorganisms. The surface gel coat of the vinyl ester and epoxy materials did not change in appearance and was not attacked or damaged by the bacteria. No conclusions could be drawn about the phenolic material. Although it did not appear damaged to the naked eye, the gel coat was so fragile that it was attacked by the chemicals and procedures required to examine the coupons in detail.
