This Asia Pacific client's completion system had an integrity issue whereby the production packer installed in 1995 was not sealing the tubing to casing annulus. Being an older facility, the drilling substructure had previously been removed and a solution to restore production integrity using non-rig assist through tubing intervention technologies was required.
The innovative solution developed and employed was to create an impermeable annular barrier directly above the compromised production packer seal, through the in-situ completion tubing utilizing an electric wireline set inflatable retrievable bridge plug system, for diversion, along with a bismuth-based metal-to-metal sealing alloy actuated by means of a thermite heater. This unique solution included drilling the tubing above the production packer with an e-line deployed system to provide multiple communication ports to the annulus, an e-line set inflatable retrievable bridge with a modified, extended fish neck was then set utilizing wellbore fluid as the inflation medium. The bismuth alloy metal sealing particulate (pellets) were positioned via a dump bailer above the inflatable plug which directed them to the tubing / casing annulus to gravitate to their position and calculated radial height within the compromised annulus. Once positioned the inflatable bridge plug was retrieved via slickline. An e-line conveyed thermite-based heater module was then deployed to complete the process of forming the bismuth-based alloy seal allowing for a permanent annular barrier to be created. Once accomplished and integrity confirmed a straddle/patch system was run to re-seal the tubing / casing annulus drilled holes, prior to the well-being returned to production.
This paper will focus on this rigless intervention operation conducted in July 2021 as it relates primarily to the engineering and installation and retrieval of the bridge plugs and the development, engineering, and installation of the bismuth-based metal to metal sealing alloy, allowing repair to be completed and the well handed over in a position of full integrity.