Premature failure of tubing used in sweet Extra Arab Light grade crude oil production well. (January 2015)

• Record Type: Journal Article
• Authors: Al-Jaroudi, Said S.; Ul-Hamid, Anwar; Al-Moumen, Mohammed A.
• Is Part Of: Engineering failure analysis. Volume 47 Part A(2015:Jan.)
• Page Start: 178
• Page End: 198
• Publication Date: 2015-01
• Subjects: Wet sweet Extra Arab Light -- Oil production well -- API 5CT grade J-55 carbon steel -- Sweet CO2 corrosion -- Mesa attack; System failures (Engineering) -- Periodicals; Fracture mechanics -- Periodicals; Reliability (Engineering) -- Periodicals; Pannes -- Périodiques; Rupture, Mécanique de la -- Périodiques; Fiabilité -- Périodiques; Fracture mechanics; Reliability (Engineering); System failures (Engineering); Periodicals; Electronic journals; 620.112
• DOI: 10.1016/j.engfailanal.2014.10.006
• Languages: English
• ISSNs: 1350-6307

Abstract

Highlights: Internal corrosion as well as localized pitting at failed locations was observed. Visual inspection revealed plastic deformation of tubing alloy at localized regions. Predominant mode of failure was sweet CO2 corrosion in the form of mesa attack. SEM showed clear chloride attach to the failed tube. Abstract: A 30 feet long and 3.5 in. 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 X-ray spectroscopy. The corrosion product was identified using photometric and potentiometric analysis combined with X-ray diffraction. Gas and water samples obtained from the production well were also analyzed. The material of the production tubing was identified as API 5CT grade J-55 carbon steel. Visual inspection revealed plastic deformation of tubing alloy at localized regions and internal corrosion as well as localized pitting at failed locations. Evidence of external corrosion was not found. Predominant mode of failure was sweet CO2 corrosion in the form of mesa attack combined with chloride corrosion. Operating conditions of low pH, high pressure and high temperature along with presence of organic acid is thought to be responsible for the observed mesa attack. Replacement with a super 3–13% Cr production tubing and application of cathodic protection were suggested as a permanent solution to the corrosion problem whereas a number of short-term measures were also recommended.