Progressive cavity pump system having reverse mode
A progressive cavity pump (PCP) system includes a PCP with a rotor rotatably disposed in a stator, a permanent magnet motor, sucker rod(s), and a control system. The rotor is coupled to one of the sucker rods via a high-torque connection that allows for counter clockwise rotation without loosening the connection between the rotor and sucker rod. The control system operates the system in a production mode by rotating the rotor clockwise. Upon manual input by a user, or automatic triggering when protections settings of the control system call for a shutdown or cleanout or when the control system senses an imminent pump shutdown, the control system operates the system in a reverse mode by rotating the rotor counterclockwise. The reverse mode pumps fluids and suspended solid particles down into the well prior to pump shutdown to inhibit the solids from clogging the pump or preventing the pump from restarting.
1 . A method of operating a progressive cavity pump (PCP) system, the system comprising a PCP disposed in a wellbore, the method comprising:
operating the PCP system in a production mode, wherein in the production mode a motor of the PCP system drives rotation of a sucker rod coupled to a rotor of the PCP to rotate the rotor in a first direction to pump a fluid from a reservoir in an uphole direction through the PCP; and
performing a pump shutdown of the PCP system, wherein a column of the fluid is above the PCP and the pump shutdown comprises:
operating the PCP system in a reverse mode, wherein in the reverse mode the motor drives the rotation of the sucker rod coupled to the rotor to rotate the rotor in a second direction opposite the first direction to pump the column of the fluid in a downhole direction through the PCP;
monitoring a torque of the PCP; and
stopping the rotation of the rotor of the PCP while operating in the reverse mode to shut down the PCP in response to determining the PCP is approaching a run dry condition to avoid the run dry condition, wherein determining the PCP is approaching the run dry condition includes determining the torque has reached a predetermined setpoint.
2 . The method of claim 1 , wherein the first direction is a clockwise direction.
3 . The method of claim 1 , wherein the second direction is a counter-clockwise direction.
4 . The method of claim 1 , wherein the reverse mode is configured to pump solid particles suspended in the column of the fluid down the wellbore prior to stopping the rotation of the rotor.
5 . The method of claim 1 , further comprising receiving an input from a user into a control system of the PCP system, wherein the input from the user includes an instruction to perform the pump shutdown, and wherein the PCP system is operated in the reverse mode in response to the input received from the user.
6 . The method of claim 1 , wherein the PCP system is operated in the reverse mode automatically in response to a control system of the PCP system determining the PCP system is shutting down.
7 . A progressive cavity pump (PCP) system comprising:
a PCP comprising a rotor rotatably disposed within a hollow stator, the PCP configured to be disposed downhole in a borehole of a well;
a permanent magnet motor (PMM) configured to be disposed at a surface of the well;
a sucker rod coupled to the rotor of the PCP via a connection and operatively coupled to the PMM, wherein in use, the PMM drives rotation of the sucker rod to rotate the rotor; and
a control system configured to control operation of the PCP system, the control system configured to:
operate the PCP system in a production mode, wherein in the production mode the PMM drives rotation of the sucker rod coupled to the rotor to rotate the rotor in a first direction to pump a fluid from a reservoir in an uphole direction through the PCP; and
perform a pump shutdown of the PCP system, wherein a column of the fluid is above the PCP and the pump shutdown comprises:
operating the PCP system in a reverse mode, wherein in the reverse mode the PMM drives the rotation of the sucker rod coupled to the rotor to rotate the rotor in a second direction opposite the first direction to pump the column of the fluid in a downhole direction through the PCP;
monitoring a torque of the PCP; and
stopping the rotation of the rotor of the PCP while operating in the reverse mode to shut down the PCP in response to determining the PCP is approaching a run dry condition to avoid the run dry condition, wherein determining the PCP is approaching the run dry condition includes determining torque has reached a predetermined setpoint.
8 . The PCP system of claim 7 , wherein the connection is configured to isolate axial forces on a junction of the sucker rod and the rotor from circumferential forces on the junction.
9 . The PCP system of claim 7 , wherein the connection comprises a tapered projection at a lower end of the sucker rod and a corresponding recess at an upper end of the rotor.
10 . The PCP system of claim 7 , the control system further configured to control backspin speed and torque when operating the PCP system in the reverse mode.
11 . The PCP system of claim 7 , the control system comprising one or more user interfaces configured to receive input from a user.
12 . The PCP system of claim 7 , further comprising one or more sensors configured to monitor one or more parameters of the PCP system and/or the well.
13 . A control system for a progressive cavity pump (PCP) system including a PCP, the control system comprising:
a display screen;
one or more user interfaces; and
a processor configured to:
operate the PCP system in a production mode, wherein in the production mode a motor of the PCP system drives rotation of a sucker rod coupled to a rotor of the PCP to rotate the rotor in a first direction to pump a fluid from a reservoir in an uphole direction through the PCP disposed in a wellbore; and
perform a pump shutdown of the PCP system, wherein a column of the fluid is above the PCP and the pump shutdown comprises:
operating the PCP system in a reverse mode, wherein in the reverse mode the motor drives the rotation of the sucker rod coupled to the rotor to rotate the rotor in a second direction opposite the first direction to pump the column of the fluid in a downhole direction through the PCP;
monitoring if a torque of the PCP reaches a predetermined setpoint; and
stopping the rotation of the rotor of the PCP while operating in the reverse mode to shut down the PCP in response to determining the PCP is approaching a run dry condition to avoid the run dry condition, wherein determining the PCP is approaching the run dry condition includes determining the torque of the PCP has reached the predetermined setpoint.
14 . The control system of claim 13 , wherein the processor is further configured to control backspin speed and torque when operating the PCP system in the reverse mode.