| 摘要 |
<p>A pumping tool for incorporation in a dill string, and a sleeve around the mandrel provided with internal turbine blades arrange to rotate the mandrel in response to flow of drilling mud through the annulus between the mandrel and the sleeve. A helical external blade on the sleeve provides a return pumping action around the drill string to reduce bottom hole hydrostatic pressure. Two counter-rotating mandrels are pref. used to provide torque balance.</p> |
