Premature Failure of Tubing Joint used in a Crude Oil Production Well (original) (raw)

A 30 feet long and 3.5 inch diameter joints tubing used in wet sweet Extra Arab Light grade crude oil production well failed after 3 years of service. The bottom-hole temperature and pressure were, 82°C and 170 atm, respectively. The tubing had a nominal wall thickness of 6.45 mm and was located at starting depth of 1465 m. The average production rate and water cut of the oil well during the last 3 years of operation were 8761 BPD (barrel per day) and 7.72%, respectively. Failure occurred due to corrosion resulting in leaks of three out of 5 consecutive joints of the tubing. On the other hand, rest of the 120 joints did not show any leaks. All failures occurred close to the joints. Various sections of the failed joints were metallurgically evaluated using scanning electron microscopy coupled with energy dispersive