High Pressure Washpipe Assemblies

In this drilling swivel washpipe assembly, the pressure is divided between two rotary seals mounted in high pressure bulkheads. These bulkheads incorporate laterally floating metal backup rings that minimize the size of the high pressure extrusion gaps. The illustrated assembly has a three inch bore and is engineered for 10,000 psi service. Covered by U.S. Patent No. 6007105, Australian Patent No. 746508, and U.S. Appl. Pub. 20140035238. Contact Kalsi Engineering for licensing details.
In this washpipe assembly for an oilfield drilling swivel, the high pressure is retained by a plastic lined Kalsi Seal that is supported by our patented laterally floating metal backup ring. (Click image to enlarge.)

The high pressure washpipe assemblies used in oil well drilling present difficult sealing challenges. With pressures up to 7,500 psi, and the large washpipe diameters and high speeds used in extended reach drilling, the PV values are extreme. Conventional washpipe packing sets typically only last a short while. Whenever a washpipe assembly fails, the bottom hole assembly (BHA) is typically tripped back into the casing shoe to avoid sticking during servicing of the washpipe. Since the BHA may have to be tripped as much as 4,000 meters each way, the required downtime for washpipe maintenance can result in excessively high drilling expenses.

One factor that sets Kalsi Engineering apart from other seal companies is our continual research to improve rotary seal performance, and to determine the best ways to employ seals in extreme pressure applications involving factors such as misalignment, runout, and pressure-related component deformation. The Kalsi-designed washpipe assembly uses our patented high pressure floating backup ring arrangement, which we believe to be the best mechanical arrangement for using Kalsi Seals in a high pressure washpipe assembly. Extensive developmental testing with a 2.75-inch seal shows that properly designed backup ring arrangements are capable of operating with 7,500 psi differential pressure for well over 1,000 hours at speeds up to 252 feet/minute.

Contact Kalsi Engineering for additional information.