51316-7578-Linking sulfur cycling and MIC in offshore water transporting pipelines

Available for download

Product Number: 51316-7578-SG

ISBN: 7578 2016 CP

Author: Jaspreet Mand

Publication Date: 2016

Member Price: $0.00

Non Member Price: $20.00

Price: $20.00

Qty:

Microbial activities in oil and gas operations cause souring the production of sulfide by sulfate-reducing bacteria (SRB) and microbially-influenced corrosion (MIC). MIC may be especially severe in offshore produced water reinjection operations when deaerated seawater containing some residual oxygen is mixed with sulfide containing produced water prior to reinjection in the reservoir. We have studied samples from these systems and have also obtained samples from an onshore storage lagoon for produced water which is subject to more extensive oxygen ingress. We have investigated the samples using chemical analyses culture-based microbial counts and whole microbial community composition using molecular DNA-based techniques (pyrosequencing). We found that (i) sulfate reduction by SRB (Desulfovibrio Desulfobacterium Desulfobacter) leads to the formation of sulfide in these systems that (ii) sulfide is reoxidized to form elemental sulfur (S0) both abiotically and through the metabolism of sulfide-oxidizing bacteria (Sulfurimonas Arcobacter) and that (iii) S0 is converted back to sulfide by sulfur-reducing bacteria (S0RBDesulfuromonas Desulfuromusa) and by sulfur-disproportioning bacteria (Desulfovibrio Desulfococcus Pantoea) completing the sulfur cycle. Samples from these seawater systems have significant sulfate sulfide and sulfur (S0) concentrations and all reactions (i) to (iii) can be demonstrated to occur. We find that the presence of elemental sulfur which is increased by reactions (i) and (ii) and decreased by reaction (iii) gives rise to considerably increased corrosion risk towards steel infrastructure.