At the Deepwater Decommissioning Gulf of Mexico 2021 Virtual Workshop, Kevin Squyres, Sales and Service Delivery Manager, Archer, presented the Stronghold systems: the latest set of innovations from Archer Oiltools which offer an economical effective alternative to traditional methods of plug and abandonment (P&A).
Squyres explained how, by eliminating the need for milling, Archer’s Stronghold systems have the capacity to deliver more efficient P&A operations. When used in conjunction with Tubing Conveyed Perforating (TCP) products and new charge developments, the systems give economical and safe execution of operations providing time and cost savings for customers. The systems have been tried and tested in multiple environments across the globe including, the Gulf of Mexico, Alaska, the North Sea, the Middle East, Asia, and Australia.
Going into more detail, Squyres outlined the three tools for barrier verification and setting which make up Stronghold systems.
Barrier Verification
Archer Oiltools’s verification solutions consist of the Stronghold Defender and Stronghold Fortify systems:
-The Stronghold Defender test system enables operators to efficiently perforate and test an annular barrier. It functions in three steps by first perforating the casing or liner, then verifying the integrity of the annulus, before finally placing barrier material inside the casing.
-The Stronghold Fortify system provides a reliable verification of annular integrity in just one trip which consists of perforation of the casing, testing the integrity of the annulus, verifying the annulus integrity with a unique pressure verification system and cementing across the perforated areas.
Barrier Setting
The Stronghold Barricade system, the main focus of Squyres presentation, perforates, washes, and cements the annulus in order to create a rock-to-rock barrier to achieve permanent caprock integrity.
Usually, this can be achieved in just one trip, which consists of perforating the section, at which point the guns drop automatically; thoroughly washing the perforated annular section, moving down and up if required; placing spacer fluid in the annulus using the calculated pump and pull method; and placing the barrier material using the same technique, once the blank casing is reached the ball will automatically shear out. At this point the pumps are stopped and the operator will pull above expected top of cement to circulate/reverse out any residual cement in the drill pipe.
Squyres explained that in the Gulf of Mexico frequently rat holes are not available and so two trips may be required, but even if this is the case a lot of time and cost can still be saved against a lengthy cut and pull or section milling operation for example.
To demonstrate the benefits of using the Stronghold Barricade system, Squyres outlined a case study from the Gulf of Mexico where an operator needed to set a 330 ft cross sectional cement barrier in 13 3/8” x 20” casing which had no cement in place. The well was located in more than 6,000 ft of water depth and required a barrier placed just above the 20” casing shoe. The operator wanted a barrier to be deployed in order to prevent a cut and pull.
To meet this challenge, Archer deployed the Stronghold Barricade system after working with a local provider to ensure they had the right TCP charge performance. The tool successfully washed and cemented the 330 ft long interval with even rates at 1200 lpm. A successful test thereafter showed the operation was a success and the operator was able to move on with the completion of the P&A.
By using this method, the operator was able to capture value and time by avoiding a cut and pull. Off of the successful completion of this operation, Archer has now been commissioned for several more projects in the region with this client and indeed several others.
Globally, more than 200 P&A plugs have now been installed using Stronghold systems which have delivered 99% operation efficiency, achieved US$250mn in customer savings, and saved 190 tons of CO2 emissions per barrier.
