| 摘要 |
<p>A while-drilling tool comprising a motor, a transmission coupled to the motor, and a pump comprising a first piston disposed in a first chamber and a second piston disposed in a second chamber and coupled to the first piston. A planetary roller-screw is coupled between the pump and the transmission. A valve block is configured to fluidly communicate with the first and second pump chambers, a borehole in which the while-drilling tool is configured to be positioned, and a formation penetrated by the borehole.</p> |
