Analysis, Identification and Development of Corrosion Mitigation Strategies in Songo Songo gas wells

Abstract

Corrosion has been a problem in various industrial activities where petroleum industry is one of them. The Songo Songo gas field which started production in 2004 in Tanzania has been affected by corrosion. The study that was done in 2010 revealed that some of the wells had suffered severe corrosion. Up to date three wells have been suspended due to corrosion and the plan to work over the wells is undergoing. This has stimulated further corrosion studies to be done so as to solve the problem. This thesis focused on identifying the major factors that have caused corrosion by analysing the historical production data reported on the daily basis. Other corrosion agents to the gas wells were also studied. The results obtained showed that CO2 corrosion on carbon steel to the producing wells was facilitated by higher temperature and low pH during production. Also the corrosion prediction results through a Freecorp software showed that SS10 well is at high risk to fail due to corrosion compared to SS4 and SS7 wells.Methods to mitigate corrosion in SSI wells have been suggested following the observed results and categorized into corrosion control and corrosion monitoring methods. Proper application of these methods will eliminate corrosion to SSI wells and to other fields with similar geological and operational conditions to Songo Songo gas field. It was also advised to conduct more research on corrosion to this gas field so that the best solutions can be collected and be applied.