Lubricating seal for use with a tubular

Abstract

Sealing elements have lubricating seal profiles for communicating fluid between the sealing elements and the sealed drill string tubular or other oilfield component while the sealed drill string tubular or other oilfield component rotates or moves vertically relative to the seal elements. The same fluid used for drilling may also be used for seal lubrication, such as water, drilling fluid or mud, well bore fluid or other liquid or gas. The sealing elements may be disposed with a seal housing, which may be positioned with a marine riser, or subsea without a marine riser. The seal housing may prevent rotation of the seal elements with the sealed drill string tubular or other oilfield component. Alternatively, the seal housing may be an RCD that allows the sealing elements to rotate. The lubricating seal profiles include a wave pattern, a saw-tooth high film pattern, a downwardly inclined passageway pattern, an upwardly inclined passageway pattern, and a combined upwardly and downwardly inclined passageway pattern. In one embodiment, a stripper rubber seal element may have a lubricating seal profile on the inwardly facing bore surfaces of both its nose and throat sections for sealing with drill string tubulars and other oilfield components having different diameters. Dual seals with two annular spaced apart sealing surfaces, with or without lubricating seal profiles, may seal with a drill string tubular or other oilfield component. In another embodiment, differential pressures across two seal elements may be managed by filling the cavity between the two sealing elements with cuttings-free drilling fluid, mud, water, coolant, lubricant or inert gas at desired amounts of pressure.