| 摘要 |
A system for drilling a well having a wellbore includes a first pipe string positioned in the wellbore with a first annulus being present between the first pipe string and the wellbore. A second pipe string, smaller in diameter than the first pipe string, is positioned within the first pipe string to form a second annulus between the first pipe string and the second pipe string. The second pipe string is configured to be attached to a drill bit. A first rotator is operably associated with the first pipe string to rotate the first pipe string in a first direction at a first speed, and a second rotator is operably associated with the second pipe string to rotate the second pipe string in a second direction at a second speed.
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