Paper No. 32 CORROSION 96 The NACE International Annual Conference and Exposition C02 CORROSION IN WET GAS SYSTEMS P.A. Attwood Petroleum Development Oman P.O. BOX81 Muscat, Sultanate of Oman Kees van Gelder and C.D. Charnley Petroleum Development Oman P.O. BOX81 Muscat, Sultanate of Oman ABSTRACT The failure of a pipeline used to transport wet C02 containing gas has highlighted the limitations that both intelligent surveys and ultrasonic testing (UT) inspection can have for the detection of internal grooving type corrosion. These limitations are presented, together with the inspection, testing and assessment programme that was subsequently introduced to evaluate the condition of other associated production facilities operating under similar conditions. Measures adopted to prevent the reoccurrence of such C02 induced corrosion damage are discussed. In addition, the use of a corrosion rate prediction tool enabled the risk ranking of the facilities under threat of C02 induced corrosion to be rapidly undertaken and therefore enable an inspection and assessment priority ranking to be made. A comparison is therefore made of the predicted levels of corrosion with those actually observed in practice. Keywords: carbon dioxide, grooving, hydrotest, corrosion rate prediction, wet gas INTRODUCTION On 22 March 94 a rupture occurred on 25.4 cm (inch) diameter buried pipeline used to transport approximately 1.5 MMsm3/d of wet gas (containing 0.8 mol% C02) from Yibal A station to Yibal D station. The pipeline, which had been installed in 1988, possessed a nominal wall thickness of 4.78 mm and was operating well within its agreed Copyright ------ ., .,-.-,, ,., -. .,. ––– –.—-.--L. - L, .-L,,- _— -- __ .,_, ,_ --. .’-. — :.- . . . -“:.- ,.. L.-,- —,, .-. L.- —-4- :- , . .-:.,---- .I,lr.c