Baker Hughes' Harpoon Cut and Pull Spear Saves Time

Whether working in the field or offshore, time is money, and Baker Hughes Inc. new Harpoon cut and pull spear was designed to save time and increase efficiency, Erik Nordenstam, Product Line Director for Baker Hughes, told Rigzone at the 2014 Offshore Technology Conference.

With thousands of wells at or approaching their usable lifespans, and with the cost of removing the infrastructure for one well costing millions of dollars, the cost of retrieval operations is a major expense for the industry due to the amount of time it can take.

“It generally takes a minimum of two trips to retrieve the casing – one to make the cut, and one to retrieve the casing. The Harpoon does both, and it can make multiple attempts during each trip. That saves considerable time, since it’s the trip down to the casing and back up to the surface that consumes the most time,” Nordenstam said, adding that by comparison, the time spent actually making the cut and spearing the casing is often comparatively short.

That’s when everything goes well, which it often does not, since poor cementing or a build-up of scale or other downhole factors can make setting the precise location of the spear difficult, Nordenstam explained. And that is where the advantage of the Harpoon spear comes in to play. Because the spear can be reset and used for multiple passes in a single trip, it significantly increases the chances of retrieving a length of casing in one run, Nordenstam said. This increases the safety, efficiency and economics of plug and abandonment and slot recovery operations.

Because the Harpoon casing spear does not require a stop ring, the casing can be engaged directly above the cut point, and maximum forces are transmitting during cutting operations. The spear’s design prevents deformation of the casing by spreading the loads evenly across the casing diameter. This design, in combination with tungsten carbide cutters, results in better cutting performance. Debris from the cut is controlled by a built-in filter, resulting in improved reliability.

Loads are supported in both directions by the design of the spear, allowing it to accommodate the use of fishing jars. The spear’s safety is enhanced by the inclusion of a pack-off device to control circulation paths. Well control is provided for the event that a pressurized zone is exposed during the cutting operation.

Baker Hughes recently began making their Harpoon spear commercially available. The spear was tested in the North Sea and is up for the Woelfel Best Mechanical Engineering Achievement Award, Nordenstam told Rigzone.


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