Abstract

TetrakisHydroxyMethylPhosphonium Sulfate (THPS) is used as a bactericide in the Skjold / Gorm oil production systems in the Danish sector of the North Sea. A reduction in H₂S generation downhole due to THPS treatment resulted in savings on H₂S scavenger consumption. In addition, use of THPS provides other benefits which are discussed in the paper.

THPS treatments are compared with conventional bactericidal treatments and it is demonstrated how downhole injection of THPS retards the growth rate of Sulfate Reducing Bacteria (SRB) and the rate of H₂S  production. THPS treatment resulted in a change in the downhole bacterial population, evidenced by changes in the sulfur isotope ratio of the produced H₂S .

Re-injection of produced water with low H₂S  concentrations increases the potential for iron sulfide (FeS) deposition, both in topsides and downhole. THPS changes both the physical form and the bacterial content of the FeS deposits. Removal of the deposits with acid is facilitated by THPS which exhibits FeS dissolving capabilities. Field tests have verified the effect.



Venue:    Corrosion NACExpro 2000, Orlando

Location:    Florida, USA

Authors:    J Larson, P F Sanders, R E Talbot

NACE Paper No:     00123

Date:  March 2000