| 摘要 |
A rotating blowout preventor having at least two rotating stripper rubber seals which provide a continuous seal about a drilling string having drilling string components of varying diameter. A stationary bowl is designed to support a blowout preventor bearing assembly and receives a swivel ball that cooperates with the bowl to self-align the blowout preventor bearing assembly and the swivel ball with respect to the fixed bowl. Chilled water is circulated through the seal boxes of the blowout preventor bearing assembly and liquid such as water is pumped into the bearing assembly annulus between the stripper rubbers to offset well pressure on the stripper rubbers. Lubricant is pumped into shaft bearings and serves to prolong the life of shaft. pressure seals by offsetting well pressure against the shaft pressure seals and clamp mechanisms are used to tighten the stripper rubbers on the respective mounting elements in the bearing assembly and swivel ball. A method for sealing a drilling string at the surface of a well, which method includes the steps of mounting a rotating blowout preventor having at least two sealing stripper rubbers on the well casing or other equipment connected to the well casing, in swiveling relationship, inserting a drilling string through the rotating blowout preventor and stripper rubbers, introducing a liquid into the rotating blowout preventor, circulating water around certain pressure seals and application of hydraulic pressure on the stripper rubbers and pressure seals to offset well pressure exerted against the stripper rubbers and pressure seals.
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