WAG reinstated in 6 hours
Platelets® seal 4.2mm outer annulus to conductor leak
- Client Major Operator
- Leak Location Outer Annulus - Conductor
- Location North Slope, Alaska
- Nominal Bore 9 5/8inch casing
Challenge
A water and gas (WAG) injection well was downgraded to water injection only following the identification of shallow leak from the outer annulus to the conductor, resulting in a potential annulus fluid discharge to the environment. Costly and time-consuming work would normally be required to excavate and remove the conductor casing in order to patch the leaking casing.
Solution
A set of tailored diagnostic flow tests were carried out using Telepath® to profile the leak, identifying a leak with an equivalent diameter of 4.2mm, and with approximately round geometry. Using this information, with the known well characteristics, a specific Platelet® solution was selected to create the seal, and a small number injected to the system via the annular wing valve.
Outcome
Annular pressure rose as soon as the Platelets® reached the target depth. The operation stopped the annulus to conductor communication and the well passed an MIT at 1,800 psi to reinstate full service qualification. This was achieved without having to excavate and remove the surface conductor, or pull the tubing and cut and pull the casing.
The upside
The well was certified to resume hydrocarbon injection (WAG), to regain optimum reservoir support operation. A costly excavation workover was avoided and there were minimal infrastructure and personnel requirements. The well was reinstated by simpler and much safer process than excavation and brought back to a serviceable state in a much shorter time frame than conventional processes: the entire operation was carried out in six hours with only a few minutes required to deploy the Platelets®, compared to six weeks for excavation., the only other alternative approach to repairing the integrity of the well.
