Kalsi Seals for Rotary Steerable Drilling Tools
Rotary steerable drilling systems are used in the directional drilling of oil wells. These advanced tools follow commands that are sent from the surface to accurately steer the rotating drill bit to the desired coordinates within a geological formation.
Rotary steerable tools incorporate a shaft that is coupled to and rotationally driven by the drill string, and rotates and positions the drill bit. The shaft is located within a housing by a set of bearings. Steering is typically accomplished by either pushing the housing laterally via pads that react against the wellbore, or by bending the shaft within the housing to point the drill bit. Rotary shaft seals are a critical part of these complex systems, because they are used to protect expensive internal components. The hydrodynamic interfacial lubrication provided by Kalsi-brand rotary shaft seals helps to minimize wear and prolong life.
Rotary steerable systems eliminate the sliding drillstring mode that occurs when directional drilling with conventional mud motor steering methods. Since the drillstring continually rotates when drilling with a rotary steerable system, better hole cleaning occurs and there is less chance of differential sticking. This means extended reach wells and complex well trajectories can be drilled more efficiently, with reduced risk and significant cost savings.
Sealed rotary steerable systems require that a reservoir of lubricant be provided, and require that the pressure of the lubricant be balanced to or slightly greater than the high ambient downhole pressure of the well, so that the rotary shaft seals are not exposed to high differential pressure. This typically requires the use of a pressure-balancing piston or a diaphragm. If the lubricant is pressure-balanced to the wellbore, the rotary shaft seals should be axially spring loaded to inhibit skew-induced wear.
Preferably, the primary rotary shaft seals of a rotary steerable system should be protected by outboard barrier seals. For additional information about Kalsi-brand rotary shaft seals, call 281-240-6500, or contact us by e-mail.