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 two new types of rotary seals that can be used with RCDs that have a simple gravity feed lubricator. One is an all-elastomer chamfered enhanced lubrication seal that has been tested with 450 to 500 psi drilling fluid for 300 hours at a bulk temperature of 162°F. The other is a composite grooved seal that has been tested with 1,000 psi drilling fluid for 100 hours at a bulk temperature of 153°F.
Both seal types were exposed to the pressurized drilling fluid during the tests, and used a gravity fed 150 viscosity grade lubricant. This 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.