Pump Control for Formation Testing
AssigneeSchlumberger Oilfield Services
InventorsReinhart Ciglenec, Steven G. Villareal, Albert Hoefel, Peter Swinburne, Michael J. Stucker, Jean-Marc Follini
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Abstract
A downhole formation fluid pumping and a sampling apparatus are disclosed that may form part of a formation evaluation while drilling tool or part of a tool pipe string. The operation of the pump is optimized based upon parameters generated from formation pressure test data as well as tool system data thereby ensuring optimum performance of the pump at higher speeds and with greater dependability. New pump designs for fluid sampling apparatuses for use in MWD systems are also disclosed.
Claims25
A fluid pump system for a downhole tool connected to a pipe string positioned in a borehole penetrating a subterranean formation, the system comprising:
- a pump powered by mud flowing downward through the pipe string, the pump being in fluid communication with at least one of the formation and the borehole,
- the pump being linked to a controller which controls the pump speed based upon at least one parameter selected from the group consisting of mud volumetric flow rate, tool temperature, formation pressure, fluid mobility, system losses, mechanical load limitations, borehole pressure, available power, electrical load limitations and combinations thereof.
A fluid pump system for a downhole tool connected to a pipe string positioned in a borehole penetrating a subterranean formation, the system comprising:
- a turbine powered by mud flowing downward through the pipe string;
- a transmission operatively connected to the turbine;
- a pump operatively connected to the transmission;
- a first sensor coupled to one of the turbine and the mud flow for sensing at least one of turbine speed and mud flow rate;
- and
- a controller communicably coupled to the transmission and the sensor, wherein the controller adjusts the transmission based on one of the speed of the turbine and the mud flow rate.
A method for controlling a pump of a downhole tool, the method comprising:
- providing the tool with a downhole controller for controlling a pump;
- measuring at least one system parameter of the tool disposed in a wellbore;
- calculating a pump operation limit for the pump based upon the at least one system parameter;
- operating the pump;
- and
- limiting the pump operation of the pump with the controller.
A method for of operating a pump system for a downhole tool connected to a pipe string positioned in a borehole penetrating a subterranean formation, the method comprising:
- rotating a turbine disposed in the wellbore with mud flowing downward through the pipe string;
- obtaining a power output from the turbine;
- operating a pump with the power output from the turbine;
- measuring the speed of the turbine;
- and
- adjusting a transmission disposed between the turbine and the pump with a controller disposed in the tool based on the speed of the turbine.
Dependencies are inferred from the claim text.