System Integration Test (SIT) of Technology Enabling Through-Tubing Rig-Less Plug and Abandonment

A System Integration Test (SIT), designed to investigate the performance of technology enabling through-tubing rig-less plug and abandonment is described. A key objective of this SIT was to verify and de-risk tools and techniques prior to their potential deployment in an offshore target well. A deepwater well, located offshore Brazil, was used as the basis for the design of the SIT program. The objective of the well operation was to permanently isolate the production tubing and the A-annulus in which a flatpack containing 2x chemical injection lines and 1x electrical line is present. To ensure the flatpack would not provide a leakage pathway it had to be cut into pieces prior to cementing the A-annulus. A completion string mimicking the main features of the well was designed utilizing 10 ¾in. casing, 6-5/8in. tubing with a flatpack and a restriction created by the downhole safety valve (DHSV). The completion was installed inside a large diameter test well and thereafter the technologies to be verified were deployed using wireline and rigless coiled tubing interventions. After installation of the test well completion, the performance of various technologies was investigated through the following operations: Flatpack detection with four different e-line ultrasonic & electro-magnetic tools Flatpack ablation with custom designed oriented shaped charges utilizing two different gun designs run on wireline Through tubing cement placement utilizing a Perf, Wash & Cement technique deployed on coiled tubing Coiled tubing cement mill out using a motor, bit and underreamer able to pass the DHSV and remove the cement plug from the tubing Evaluation of the annular barrier quality using a cement bond logging tool Recovery of the well completion, keeping the A-annulus barrier intact for subsequent inspection at surface and comparison to the log results The performance of state-of-the-art technologies that can enable rig-less through-tubing plug and abandonment (P&A) utilizing wireline and coiled tubing interventions have been investigated and de-risked through an SIT executed in a test well completion mimicking an actual offshore deepwater well.