An experimental investigation was conducted to determine the geometry-leakage relationship for advanced, stepped labyrinth seals. A unique, variable-geometry water test facility was constructed and used to acquire leakage resistance measurements for two-dimensional, planar models. Flow visualization techniques were also used to assist in identifying and understanding the turbulence generating flow patterns. It was found that contoured surfaces and restrictor tooth leading-edge shapes of proper dimensions can be incorporated into the cavity geometry to reduce seal leakage. Specifically, the combination of a sloping surface and a curved surface on the rotor within the labyrinth cavity gave significant improvement.

fax 01-972-952-9435. AbstractThis paper describes the successful introduction and application of a rotary steerable system for large hole sizes (17.5 and 18.25-inch.). The development of the large hole rotary steerable capability was seen to be mutually advantageous to both BP and Schlumberger. As such, this technology development was advanced as a collaborative effort.At the outset, the collaboration team identified the technology as being suitable for the intended application. Together, team members focused on the rapid development, construction, and field-testing of the rotary steerable system. Over a 9-month period, the system was designed, tested, and deployed by teams working concurrently in the UK and the USA. Prior experience gained with smaller hole sizes was used to design the system, including both the bit and the steering unit.The approach taken by BP asset teams in the Gulf of Mexico and Schlumberger contributed to accelerated initial field testing of the system in January 2002. Initial field trials proved successful. In its first application, the system was used to kick off from vertical, achieving a build rate of more than 3°/100 ft. Subsequently, the system has proven beneficial in other projects, and the value of the collaboration has been clearly demonstrated.

An experimental investigation was conducted to determine the geometry–leakage relationship for advanced, stepped labyrinth seals. A unique, variable-geometry water test facility was constructed and used to acquire leakage resistance measurements for two-dimensional, planar models. Flow visualization techniques were also used to assist in identifying and understanding the turbulence generating flow patterns. It was found that contoured surfaces and restrictor tooth leading-edge shapes of proper dimensions can be incorporated into the cavity geometry to reduce seal leakage. Specifically, the combination of a sloping surface and a curved surface on the rotor within the labyrinth cavity gave significant improvement.