Kalsi Seals-brand rotary seals have been used in rotary control devices (RCDs) for a number of years. Prior to this year, however, usage has been restricted to lubricant overpressure type RCDs, where the lubricant supply provides seal lubricant at a pressure that is several hundred psi greater than the pressure of the wellbore. A pair of Kalsi Seals is required in such systems. One seal to retain the pressurized seal lubricant, and the other to partition the wellbore fluid from the seal lubricant.
Beginning in 2014, Kalsi Engineering now offers a new type of rotary seal named the KLS® that can be used with RCDs that have a simple gravity feed lubricator. It is composite grooved seal that has been tested at 1,000 psi using a gravity fed 150 viscosity grade lubricant at a bulk temperature of 153°F. The testing was at a surface speed of 540 feet/minute, which is equivalent to 200 rpm on a 10-5/16” mandrel. These seals were developed for low cost RCDs that are used in situations where the cost of a lubricant overpressure system cannot be justified.