Fit-for-Purpose Qualification for Corrosion Resistant Alloy (CRA) Tubing Selection in High CO2 Field Based on Field Experience and Laboratory Test

Abstract

This paper focuses on tubing material selection study conducted for a high CO2 oil field located offshore of Peninsular Malaysia. The field's CO2 concentration varied laterally and with depth. The highest CO2 concentration of 66 mol% in gas had been recorded from well test and fluid data. This resulted in severe corrosive environment in the wells. Based on the well surveys, many existing wells which were completed with API-5CT L80-13Cr had suffered from localised corrosion within a span of two (2) years of production. Existing material selection was revisited in order to prevent corrosion in future development wells. An important change made was to conduct material qualification test specific for the field conditions on several corrosion resistant alloy (CRA) materials. The details of the test and findings are presented. To better understand the corrosion severity in existing well completion, well survey results are also discussed.

Degradação Dos Materiais Em Ambientes Do Pré- Sal: Uma Abordagem Tecnológica

“…A facilidade de união por solda (soldabilidade) e disponibilidade no mercado também são outros fatores relevantes 3,24 . Para equipamentos submetidos a altas pressões (poços ou linhas submersas), a alta pressão parcial do CO2 e/ou a presença de H2S indica a necessidade do uso de ligas especiais 3,21,[25][26][27] . Algumas ligas já utilizadas na indústria de óleo e gás são os aços 13Cr (supermartensítico UNSS41425), 2507 (duplex S32750) e ligas de Ni 2535 (N08535) e 29 (N08029), para ambientes com H2S e cloretos 26 .…”