Long Time Experiences in Material Selection and Corrosion Control in Oil and Gas Fields

Corrosion remains a key issue in petroleum production. Its continued occurrence has consequences on the safety of people and environment and the integrity of facilities and affects the economy ofthe oil or gas field. Especial.ly the presence ofcorrosive components such as carbon dioxide and hydrogen sulphide poses serious problems. The proper choice of materials which are both, economical and provide a satisfactory performance over the entire service life with respect to the given environment is therefore a central element in the design of facilities and the corrosion control. Reliable corrosion monitoring programmes have to be selected, established, and implemented prior to the production phase. This paper gives a comprehensive overview of the long time experience of the authors' companyregarding these considerations: one large oilfield in Austria and 4 gas fields. two of them in Austria and two in Pakistan are described. The different gas fields have been successfully developed and brought on stream between 1967 and 2003. These gas fields do not only vary in their geographical position, but also in gas compositions, the dates of production start, and the location ofgas dehydration units. The Matzen oil field has been developed in Austria more than SO years ago. Particularly for mature oil fields where the production already decreases the costs concerning new investments for facilities or OCTO could lead to the abandonment of wells with a low production rate. The respective oil field reached its peak. in the 1960s followed by a decline in oil production for the next 20 years. In the end of the 1980s - when already the abandonment of many wells was considered - the decision was made fur improved technology. In addition to an extensive inhibitor screening and optimization program the tubing and sucker rod specifications have been revised. Further, an R&D project was initiated where the abrasion resistance of rod guides and couplings has been investigated. All the measures that have derived from the projects mentioned above have led to a tremendous decrease in workovers and linepipe failures und thus to huge cost reductions. Additionally to the savings for capital and operational expenditures the loss of oil production and thus income during the shutdown period has been reduced dramatically. The production curve proves for this decision showing a significant increase in oil production. A mature oil field which could have been depleted by now ifinvestment in new technology had not been made has become very economic again.

کلیدواژه ها:

carbon dioxide ، hydrogen sulphide. mature oil field ، corrosion inhibitor.corrosion monitoring