| 摘要 |
A method of controlling the direction of drilling comprising: providing a drill bit comprising mechanical cutting means forming a bit face and a plurality of nozzles for ejecting drilling fluid arranged at different azimuthal positions with respect to the bit face, and an intermediate space between an inlet port of the drill bit and the plurality of nozzles; rotating the drill bit while passing drilling fluid comprising solids through the intermediate space and the plurality of nozzles, so as to deepen the borehole; and modifying solids concentration of drilling fluid portions flowing through the plurality of nozzles while rotating the drill bit, so that the solids concentration, for the drilling fluid portion flowing through each of the nozzles, is relatively increased when the respective nozzle is in a selected first angular sector of the borehole bottom, as compared to a second angular sector.
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