Kalsi Engineering, Inc. working with a major manufacturer has developed a new 7500 PSI Hydrodynamic Washpipe System that dramatically improves the economics of high speed, high pressure drilling. The field performance of the Hydrodynamic Washpipe Assembly has demonstrated significantly improved high speed, high pressure run-life as compared to conventional washpipe assemblies. One customer, who uses high rotary speed (180 rpm) for enhanced hole cleaning in extended reach wells, estimated that the new washpipe assembly saved an estimated $500,000 on the first well they tried it on by lasting approximately 8 times longer than conventional chevron packing.

In extended reach drilling, whenever a washpipe assembly fails the bottom hole assembly (BHA) is typically tripped back into the casing shoe to avoid sticking during the washpipe servicing. Since the BHA may have to be tripped as much as 4000 meters each way, the required downtime for washpipe maintenance can result in high drilling expenses.

The rotary shaft seal employs hydrodynamic lubrication to minimize dynamic friction and provide longer seal life. When washpipe rotation occurs, the seals hydroplane on a thin film of lubricant, which reduces the dry-rubbing type wear associated with conventional elastomeric and plastic non-hydrodynamic seals.

In conventional washpipe assemblies the rotary seals are deployed serially, such that one seal at a time is exposed to the full mud pressure until it fails, at which time the next seal in line takes over the sealing function. In the hydrodynamic washpipe assembly, the mud pressure is divided among several pressure retaining seals, so that each seal is exposed to only a fraction of the pressure. A clean lubricant is used to divide the pressure, providing the seals the best possible environment for long life.The partitioning seals are serially deployed to separate the drilling fluid from the pressurized lubricant. This serial arrangement provides for continued leak-free operation even if one partitioning seal should fail. By monitoring the lubricant supply system, the operator is able to determine the integrity of all of the seals. Having advance warning of seal degradation, the operator has the opportunity to schedule washpipe maintenance to coincide with other maintenance activities, thereby reducing operating costs. 

The assembly is covered by U.S. Patent # 6, 007,105.  Foreign patents pending.

Kalsi Engineering, Inc.   745 Park Two Drive   Sugar Land, Texas  77478-2885  Tel: (281) 240-6500    Fax: (281) 240-0255

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