High-speed rod-driven downhole pump
AssigneeWeatherford Technology Holdings, LLC
InventorsEvan Noble, Eduardo Perdomini Lara
Life of this patent
Estimating the term…
Abstract
A surface drivehead drives a downhole pump by rotating a rod string at the surface. The downhole pump can be connected downhole to the rod string via a downhole latching mechanism. The surface drivehead has an assembly that can move the rod string upwards or downwards along an axis to either increase or decrease rod string tension. During rod string rotation, rod tension is monitored. If rod string tension changes during rotation, the surface drivehead can automatically compensate by moving the rod string upwards or downwards along the axis to either recapture or eliminate tension. In this way, the surface drivehead can maintain a substantially constant rod string tension to drive the downhole pump at high speeds.
Claims33
A surface drivehead for rotating a rod string extending down a well, comprising:
- a motor support supporting a drivehead motor;
- a polished rod extending through the motor support and engaged with the drivehead motor;
- and
- an axial bearing assembly connected to the polished rod and engaged with one or more linear actuators,
- wherein the one or more linear actuators are configured to displace the rod string along its longitudinal axis by moving the polished rod along an axis;
- and
- wherein the drivehead activates the drivehead motor to rotate the rod string, monitors rod string tension during the rod string rotation, and activates the one or more linear actuators to maintain a substantially constant tension on the rod string.
A rod-driven pumping system, comprising:
- a surface drivehead positioned at surface;
- a rod string connected to the surface drivehead and extending downhole through a bore of a production tubing;
- and
- a downhole pump connected downhole to the bottom of the rod string,
- wherein the surface drivehead is capable of driving the downhole pump by rotating the rod string at the surface;
- wherein the surface drivehead comprises an axial bearing assembly connected to the rod string and engaged with one or more linear actuators,
- wherein the one or more actuators are configured to displace the rod string along its longitudinal axis, and
- wherein the drivehead monitors rod string tension during the rod string rotation and activates the one or more linear actuators to maintain a substantially constant tension on the rod string.
A method of driving a downhole pump from a surface at high speeds, comprising:
- activating a surface drivehead positioned at the surface to rotate the rod string connected to the downhole pump, wherein the surface drivehead comprises a polished rod for moving a top end of the rod string upwards and downwards along an axis;
- activating the surface drivehead to move the top end of the rod string along the axis to achieve a predetermined rod string tension;
- monitoring the rod string tension during the rod string rotation;
- and
- maintaining the rod string at a substantially constant rod string tension.
Dependencies are inferred from the claim text.