High-speed rod-driven downhole pump

摘要

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.

主权项

1. 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.