| 摘要 |
A pump system for a downhole tool comprises a pump 41a which is powered by mud 17a flowing downward through a drill string. The pump is in fluid communication with the formation or borehole 18. The pump is linked to a controller, preferably tool embedded software, which controls the pump speed based upon a parameter of the system. The parameter is selected from mud flow rate, tool temperature, borehole or formation pressure, fluid mobility, system losses, mechanical or electrical load limitations, available power or combinations thereof. The pump may be linked to a gearbox 48a linked to a turbine 37a driven by the mud flow. The mud flow to the turbine may be controlled by a throttle valve 123 linked to the tool embedded software. The pump system may be used in conjunction with a formation sampling device 31a. In a second aspect, a pump system includes a controller that adjusts a transmission operatively linked to the turbine. In a further aspect, a method includes limiting the pump operation. |
