Pressure testing completion tubing prior to setting the production packer has been an accepted procedure in the past. However, over the years, complications and time (cost) to run a plug (on slick line) in high angle wells plus the advent of premium tubing connection and use of torque-turn monitor has made that practice almost redundant. Reliance on a metal to metal seal provided by premium connection, mill end quality control and tubing thread inspection are the main reasons for avoiding completion tubing pressure test prior to setting production packer.
This paper described the painful recovery, costing over US$ 4.8 million from a tubing connection leak despite the use of premium connection and torque-turn monitoring system. Troubleshooting the location of the leak is time consuming. Is the packer leaking or any of the completion components or the tubing leaking?
In this case one of the 13 Cr completion tubing connection was leaky. The completion string had an Integral Tubing Conveyed Perforation gun below the retrievable packer so it was time consuming and risky to retrieve tubing completion with a life gun. Over 40% of tubing had to be rejected due to galled thread when the completion was pulled.
A description of field trouble shooting the leak location is described. Analysis of the torque -turn graph and reasons for imperfect tubing make up causing the leak are discussed. Simulating field make-up process at the Yard and pressure testing the made-up premium connection are described. Lessons learned are presented.