Well BO-X is located in offshore East Malaysia and was completed as a single string producer on 22nd July 2014. Well BO-X has maximum deviation of 57.5 deg at depth 3,150ft MDTHF. Based on the MIT logs, several leaks have been detected on the string which caused the well unable to flow. Well was flowing for 2 years before identified with multiple leaks due to severe metal loss and high penetration along more than 1,400 ft tubing interval (400 ft above the TRSCSSV and 1000ft below the TRSCSSV). Multiple attempts tried to flow well but failed due to circulation of gas through leak points at tubing. Tubing was found to be leaking at multiple points above TRSCSSV (449 ft MDTHF) with severe pitting / penetration at a single point below between ESP discharge head and TRSCSSV from 2 MIT runs. The leaks were detected at depth (1) 64 ft MDTHF, (2) 126.8 ft MDTHF and (3) 221.2 ft MDTHF. There were also several potential leaks detected along the long string above the top packer

Reservoir simulation studies and production rate both indicated that the production tubing leaks is deteriorate and few methods were considered to bring back the optimum production. Tubing pack off system technique was considered as it can deploy with slickline, retrievable and ideal use to isolate tubing leaks however there is potential that more leaks will develop along the production years. Workover as an option to replace the tubing could easily cost millions of dollar (USD)

Before surrender the well to workover team, a coiled tubing patch system was designed in a cooperative project involving operator and service company to provide an improved tubing pack off system which can straddle the tubing leaks by using coiled tubing instead of spacer pipe. This coiled tubing patch system was significantly lower cost and keep the functionality of Tubing Retrievable Surface Control Subsurface Safety Valve (TRSCSSV) by installing two straddle packer system – upper straddle packer system to cover leak points above TRSCSSV while another straddle system to cover leak points below TRSCSSV (Fig 1).

You can access this article if you purchase or spend a download.