CA3146427A1 - Systems and methods for identifying shaft failure in a pump - Google Patents

Abstract

A method for identifying a shaft failure in a pump, wherein the pump includes at least one impeller mounted on an impeller shaft portion of a rotor of a prime mover. The impeller shaft portion of the rotor is rotatable by the prime mover for rotating the at least one impeller for transmitting kinetic energy to reservoir fluid being supplied to the pump. The method comprises monitoring torque applied to the rotor and monitoring speed of the rotor, over a monitoring time interval, such that monitored rotor data is obtained over and spans the monitoring time interval. The monitored rotor data includes monitored torque data and monitored speed data and a shaft failure condition is determined based on the monitored rotor data.

Description

SYSTEMS AND METHODS FOR IDENTIFYING SHAFT FAILURE IN A PUMP
TECHNICAL FIELD
[0001] The present disclosure relates to identifying shaft failures in pumps.
BACKGROUND

[0002] Pumps are used in a variety of applications, such as sewage, water, agriculture, petroleum and petrochemical pumping. Some pumps, for example, centrifugal pumps, use rotational energy, which can be translated into hydrodynamic energy causing the fluid in the pump to flow. These pumps generally comprise a shaft which is connected to a motor; the motor provides rotational energy to the shaft, which in turn rotates impellers that are attached to the shaft, causing the fluid to gain pressure and velocity. In many applications, these pumps are installed in inaccessible locations, such as underground, making it challenging to diagnose problems with the pumps without physically removing the pumps from their installed locations and inspecting the pumps.

[0003] By way of example, in steam-assisted gravity drainage (SAGD) processes, electrical submersible pumps (ESP) are used to draw petroleum products from a reservoir deep in the ground. ESP systems typically include a motor positioned below a centrifugal pump such that the pump intake is above the motor and the motor is continuously submersed in the petroleum product(s). By using the ESP system as such, a relatively small borehole can be used to access and retrieve large volumes the petroleum products deep in the ground.

[0004] As with most equipment, ESPs occasionally experience failures, stop working or have problems, such as broken components. While control systems can show that there is an issue with the ESP, for example, by showing that the pump is not producing any petroleum products, the cause of the problems are often not clear from the control systems, requiring the removal of the ESP system in order to diagnose the issue. Since the ESP system is installed in the small borehole, it can Date Recue/Date Received 2022-01-21 be challenging to diagnose any problems arising with the ESP without pulling the entire ESP system from the borehole. Removing the ESP system from the borehole is a costly process and results in substantial downtime for the boreholes.

[0005] Certain problems can be addressed without removing the ESP
system from the borehole. Other problems, such as a shaft failure, have typically only been diagnosable by removing the ESP from the borehole. Accordingly, there is a need to identify whether a pump has a broken shaft without removing the pump from the installed location.
SUMMARY

[0006] In one aspect, there is provided a method for identifying a failure of a rotor of a pumping system, the pumping system comprising a pump connected to a drive with the rotor. The method comprising: monitoring torque being applied to the rotor and monitoring speed of the rotor such that monitored rotor data is obtained; and determining if a rotor failure condition exists based on the monitored rotor data.

[0007] In some examples, the existence of the rotor failure condition is determined when the monitored rotor data defines rotor-failure indicative data that spans a time interval of less than ten (10) minutes and is representative of a decrease of at least 50% in torque being applied to the rotor while there is an absence of variability in the speed of the rotor of greater than 10%.

[0008] In some examples, the decrease in applied torque is a decrease of 100 /0, such that the decrease is with effect that there is an absence of torque being applied to the rotor.

[0009] In some examples, the decrease is a decrease from a baseline applied torque, and the baseline applied torque is at least 40 newton metres.

[0010] In some examples, the time interval, over which the rotor-failure indicative data spans, is less than five (5) minutes.

Date Recue/Date Received 2022-01-21

[0011] In some examples, the absence of variability in the speed of the rotor is an absence of variability of greater than 5%.

[0012] In some examples, the existence of the rotor failure condition is determined when the monitored rotor data defines rotor failure-indicative data that spans a decreasing torque profile-defining time interval and has a duration of less than ten (10) minutes and is representative of a decreasing applied torque profile of torque being applied to the rotor while there is an absence of variability in the speed of the rotor of greater than 10%, and the decreasing applied torque profile defines a decrease in torque, being applied to the rotor, of at least 50%.

[0013] In some examples, the decrease in torque is a decrease of 100 /0, such that the decrease is with effect that there is an absence of torque being applied to the rotor.

[0014] In some examples, the decrease in torque is a decrease from a baseline applied torque, such that the decreasing applied torque profile defines the baseline applied torque, and the baseline applied torque is at least 40 newton metres.

[0015] In some examples, the decreasing torque profile-defining time interval is less than five (5) minutes.

[0016] In some examples, the absence of variability in the speed of the rotor is an absence of variability of greater than 5%.

[0017] In some examples, the monitored rotor data comprises monitored torque data, the decrease in applied torque is a decrease from a baseline applied torque, such that the decreasing applied torque profile defines the baseline applied torque, the monitored torque data, within a preceding time interval of five (5) minutes that immediately precedes the decreasing torque profile-defining time interval, defines torque data that is representative of a minimum applied torque Date Recue/Date Received 2022-01-21 applied to the rotor during the preceding time interval, and the baseline applied torque has a value that is less than or equal to that of the minimum-applied torque.

[0018] In some examples, the baseline applied torque is at least 40 newton metres.

[0019] In some examples, the pump is a centrifugal pump.

[0020] In some examples, the pump is an electrical submersible pump.

[0021] In some examples, the pump comprises at least one impeller mounted on an impeller shaft portion of the rotor, and the rotor failure condition comprises a failure of the impeller shaft portion.

[0022] In some examples, the failure of the impeller shaft portion includes a snapped shaft.

[0023] In some examples, the drive comprises an electric motor.

[0024] In some examples, the monitoring of the applied torque is effectuated with a torque sensor, and the monitoring of the speed is effectuated with a speed sensor.

[0025] In some examples, the drive comprises an electric motor.

[0026] In some examples, the drive further comprises a variable frequency drive disposed in signal communication with the motor, and the variable frequency drive comprises the torque sensor and the speed sensor.

[0027] In some examples, the monitored rotor data is obtained during pumping of fluid by the pumping system.

Date Recue/Date Received 2022-01-21

[0028] In some examples, the method further comprises, in response to determining that a rotor failure condition exists, suspending the rotation of the rotor.

[0029] In some examples, the method further comprises, in response to determining that a rotor failure condition exists, presenting an indication of the rotor failure condition via an output device.

[0030] In some examples, the method further comprises, in response to the monitoring, sensing an absence of torque being applied to the rotor in the absence of a determination of an existence of a rotor failure condition, and performing a further analytical evaluation for determining a cause for the sensed absence of torque.

[0031] In some examples, the pumping system is disposed within a wellbore extending into a subterranean formation from a surface.

[0032] In some examples, the monitored rotor data is obtained during pumping of fluid by the pumping system, and the pumping comprises pumping of reservoir fluid from the subterranean formation to the surface.

[0033] In some examples, the reservoir fluid comprises oil.

[0034] In some examples, the method further comprises, in response to determining that a rotor failure condition exists, suspending rotation of the rotor.

[0035] In some examples, the method further comprises, after the suspending of the rotation of the rotor, removing the pumping system from the wellbore.

[0036] In some examples, the method further comprises, in response to determining that a rotor failure condition exists, presenting an indication of the rotor failure condition via an output device.

Date Recue/Date Received 2022-01-21

[0037] In some examples, the method further comprises, in response to the monitoring, sensing an absence of torque being applied to the rotor in the absence of a determination of an existence of a rotor failure condition, and performing a further analytical evaluation for determining a cause for the sensed absence of torque.

[0038] In some aspects, the present disclosure describes a system for identifying a failure of a rotor of a pumping system. The system comprises one or more processor devices and one or more memories storing machine-executable instructions which, when executed by the one or more processor devices, cause the system to perform any of the preceding example aspects of the method.

[0039] In some aspects, the present disclosure describes a system for identifying a failure of a rotor of a pumping system, the pumping system comprising a pump connected to a drive with the rotor. The system comprises a torque sensor, a speed sensor, one or more processor devices, and one or more memories storing machine-executable instructions, which when executed by the one or more processor devices, cause the system to: monitor torque being applied to the rotor, using the torque sensor, and monitor speed of the rotor, using the speed sensor, such that monitored rotor data is obtained, and determine if a rotor failure condition exists, based on the monitored rotor data.

[0040] In some example aspects, the present disclosure describes a non-transitory computer-readable medium storing machine-executable instructions thereon. The instructions, when executed by one or more processors, cause the processor to perform any of the preceding example aspects of the method.

[0041] In some embodiments, the techniques described herein can be used to identify when there is a shaft failure in a pump. In this respect, the techniques described herein can improve pump diagnostics and minimize the need to shut down pump operation or remove the pump from its installed location for maintenance.

Date Recue/Date Received 2022-01-21 BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Reference will now be made, by way of example, to the accompanying drawings which show example embodiments, and in which:

[0043] Figure 1 shows a schematic diagram of an electrical submersible pump (ESP) system;

[0044] Figure 2 is a graph illustrating applied torque as a function of time for an exemplary operation of a pump;

[0045] Figure 3 is a graph illustrating applied torque as a function of time for an exemplary operation of a pump, wherein, during the pump operation, the rotor experiences a brief, temporary increase in torque;

[0046] Figure 4 is identical to Figure 3, and further defines a decreasing applied torque profile, that is representative of the monitored rata data, and spans the decreasing torque profile-defining time interval; and

[0047] Figure 5 is similar to Figure 4, except that the applied torque decreases to a greater extent at time T2, than in Figure 4.
DETAILED DESCRIPTION

[0048] The present disclosure describes methods for identifying a defective rotor (e.g. impeller shaft) of a pump, based on monitored rotor data. The monitored rotor data includes monitored torque data and monitored speed data.

[0049] The pump is connected to a drive via a rotor. In some embodiments, for example, the rotor includes at least one shaft. Exemplary drives include an electrical motor, a diesel drive, a hydraulic motor or other means of transmitting energy to the shaft. In the present disclosure, the term "motor" will be used to refer to this drive, but it will be understood that any means of providing energy to the pump can be implemented. The motor converts electrical energy into mechanical energy of a motor shaft, which defines a motor shaft portion of the Date Recue/Date Received 2022-01-21 rotor, to cause the pump to impart energy to a fluid and thereby cause the fluid to flow.

[0050] In some embodiments, for example, the pump is a centrifugal pump (i.e. pumps that use rotational energy to cause fluid to flow), such as, for example, an electrical submersible pump ("ESP"). Centrifugal pumps are comprised of an impeller that rotates inside a pump casing. The impeller has a series of blades formed in a radial arrangement that can transmit kinetic energy to the fluid upon rotation of the impeller. The impeller is attached to the rotor. In this respect, the motor converts electrical energy to rotational energy of the rotor which, in turn, transmits the rotational energy to the impeller, such that the impeller is caused to rotate. In some embodiments, for example, the impeller is attached to an impeller shaft, which defines an impeller shaft portion of the rotor, and the impeller shaft is connected to the motor shaft portion, such that the rotational energy is transmittable to the impeller via the motor shaft and the impeller shaft.

[0051] In some embodiments, for example, the motor is connected to the pump using a fixed connection. When a pump and motor are connected in a fixed connection, the pump and motor housing (casing) are fastened together, for example, via flanges, and the pump impeller is mounted directly on the motor shaft such that the shaft, of the rotor, is common to both of the motor and the pump. In other example embodiments, the motor and the pump are in a direct connection, in which the motor and pump are not co-axially connected and thus a flexible connection is used to allow for slight axial misalignment between the motor and the pump. Regardless of the means of connecting the two together, the motor and pump can be configured such that when the motor shaft rotates, the pump shaft rotates as well.

[0052] Fluid to be pumped enters the centrifugal pump at an intake.
While the impeller rotates, the fluid acquires energy, primarily in the form of an increase in its velocity (i.e. an increase in kinetic energy). As the impeller rotates, the centrifugal force causes the fluid to be forced radially outward from the impeller into the pump Date Recue/Date Received 2022-01-21 casing. The fluid is then directed out a discharge nozzle resulting in an increase in pressure at the pump outlet. This increase in pressure in the fluid is often referred to as pump head.

[0053] When there are problems with a pump, it can be difficult to diagnose the problems, especially when the problems arise due to internal components of the pumps. For example, many pumps are located within a casing that protects the internal components of the pump from the exterior environment. While the casing can protect the interior components, it also requires the removal of the casing to identify what, if any, internal components have caused the issue. Pumps can also be installed in inaccessible locations or within larger systems that make it challenging to access and observe the pump and its components. As such, when problems arise with a pump due to a rotor (e.g. shaft) failure, it can be difficult to identify the particular cause of the problems and often requires removal of the pump from its installed location and/or dismantling of the pump which can create substantial downtime for the equipment or system in which the pump is used.

[0054] In some embodiments, for example, the pump is part of a system for producing reservoir fluid from a reservoir within a subterranean formation via the wellbore. "Reservoir fluid" includes fluid that is contained within a reservoir. The reservoir fluid can also include fluids injected into the reservoir for effecting stimulation of resident fluids within the reservoir. Reservoir fluid can be liquid material, gaseous material, or a mixture of liquid material and gaseous material. In some embodiments, for example, the reservoir fluid includes hydrocarbon material, such as oil, natural gas condensates, or any combination thereof. In those embodiments where the reservoir fluid includes hydrocarbon material, in some of these embodiments, for example, the reservoir fluid also includes water.

[0055] In some embodiments, for example, the system includes a production string, including a reservoir production assembly, disposed within the wellbore. The reservoir production assembly includes a pump and a pressurized gas-depleted reservoir flow conductor (e.g. production tubing). The pump includes a suction (e.g.

Date Recue/Date Received 2022-01-21 an intake) and a discharge. The pressurized gas-depleted reservoir flow conductor is fluidly coupled to the pump discharge for conducting reservoir fluids to the surface.

[0056] Electrical submersible pumps (ESP) are a type of centrifugal pump that are commonly used in hydrocarbon operations for lifting large volumes of reservoir fluid from a wellbore 118. Figure 1 shows an example embodiment of an ESP
system 100 deployed in a wellbore 118. An ESP system generally comprises a centrifugal pump (i.e. the ESP) 106, a motor 102, a seal chamber section 104, and surface controls 108. These components are generally comprised within tubing hung from the wellhead (i.e. the surface 120 of the well) with the pump at the upper end and the motor at the lower end. In some embodiments, the ESP system 100 can include other components, such as a gas separator 114.

[0057] In some embodiments, the centrifugal pump 106 in an ESP system 100 is multi-staged, meaning that it is generally designed with two or more impellers. The stages of the centrifugal pump 106 are generally stacked vertically.
These impellers can be installed on the same shaft but can also be installed on different impeller shafts. The pump 106 can be designed to direct fluid from the discharge of one impeller to the inlet of the next impeller. The use of several stages in the centrifugal pump 106 allows the fluid to gain more pressure than with a single stage. As the fluid being pumped leaves each stage of the pump 106, the fluid has a higher pressure than it had upon entering the stage of the pump 106. As the fluid passes through all of the pump stages, it gains pressure incrementally such that upon leaving the pump 106, the fluid has reached a desired discharge pressure that provides the fluid with sufficient energy to travel to the surface 120 of the well.

[0058] ESP systems 100 are typically deployed in wellbores 118 with a limited diameter, which limits the ability of a single impeller to generate the necessary pump head. Accordingly, several stages are combined in order to maintain the limited diameter of the well casing and supply the required pump head. Each stage Date Recue/Date Received 2022-01-21 of the pump 106 can add energy to the fluid in the form of increased velocity and pressure.

[0059] The motor 102 in an ESP system 100 is generally an electromechanical motor that can convert electrical energy into mechanical (i.e. rotational) energy.
The motor 102 is located below the centrifugal pump 106 in an ESP system 100.
The motor 102 is generally designed to operate within the high temperatures (e.g.
up to 500 F) and high pressures (e.g. up to 5000 psi) that exist within the wellbore 118. The motor 102 in an ESP system 100 is located below the pump 106, for submersion within wellbore fluids. This allows the wellbore fluids to act as cooling agents for the motor 102.

[0060] The seal chamber section 104 is located between the motor 102 and the pump 106 and isolates the motor 102 from the well fluid. The seal section also houses the thrust bearing that carries the axial thrust of the pump 106 and can assist in equalizing the pressure within the wellbore 118 with the pressure inside the motor 102. The seal chamber section 104 is generally provided to provide increased motor 102 protection.

[0061] The surface controls or surface equipment 108 includes a variety of equipment used in monitoring and controlling well performance and operation.
The surface equipment 108 includes the well tubing head which is designed to support the downhole equipment (e.g. motor, seal section, centrifugal pump). The surface equipment 108 can also include a system controller 110 and a variable frequency drive (VFD). The system controller 110 can comprise a control and data acquisition system or other controller which allows operators and engineers to observe the sensed data from a variety of components in the ESP system 100. The VFD uses variable frequency and voltage to vary the speed of the rotor, as well as the torque applied to the rotor. The VFD is connected to the system controller 110 such that operators can monitor the applied frequency and voltage, and monitor the corresponding torque being applied to the rotor, and also monitor the speed of the rotor. The VFD enables the ESP system 100 to operate continuously and provide Date Recue/Date Received 2022-01-21 variable flow and pressure control, which allows operators to respond to changing operating conditions, and provides increased productivity, flexibility in the process controls, and improved energy savings.

[0062] The ESP system 100 can also contain instruments 112, such as downhole sensors, in order to monitor wellbore condition and ESP conditions, such as pump intake pressures and temperatures, pump discharge pressures and temperatures, and vibration. These sensors 112 can be connected to the system controller 110 such that the wellbore conditions and ESP conditions can be monitored throughout the operational life of the ESP. The downhole instruments 112 can be located below the other ESP components, as depicted in Figure 1. In other example embodiments, the downhole instruments 112 can be located at various locations in the wellbore 126. For example, there can be sensors located at the intake of the pump 106, in order to monitor the conditions of the fluid, wellbore 118 and the ESP system 100 at the pump intake.

[0063] The surface equipment 108 can also include an electrical supply system, which can provide electrical energy to the motor 102, and any other electrical equipment, such as monitoring instruments, controllers or other necessary electrical equipment. Electrical energy can be provided to the motor 102, and any other downhole electrical components, through a power cable 116 extending from the electrical supply system.

[0064] Operators can use the controller 110 to monitor the pump parameters, including those parameters monitored by the VFD (such as, for example, the torque applied to the rotor, and the speed of the rotor), for example, using a computer or a mobile device connected to the controller 110. These pump parameters can be stored as data over time in order to review and monitor the pump historical data.
This data can be continuously monitored (i.e. updated in real time), or can be collected and stored discretely, for example data can be collected in one minute intervals.

Date Recue/Date Received 2022-01-21

[0065] By monitoring the pump parameters, in particular the torque being applied to the rotor and the speed of the rotor, in this manner, operators are able to monitor the pump operation and identify potential and actual problems with operation. In some embodiments, the controller 110 can be configured to suspend pump operation (i.e. suspend rotation of the rotor) when the controller detects that a rotor has failed. In other example embodiments, the controller 110 can be configured to provide an alert or a notification to an output device, such as a computer or mobile device, to notify the operator(s) that the rotor has failed. In those embodiments where the pumping system is disposed within a wellbore, in some of these embodiments, for example, after the suspending of pump operation, the pumping system is removed from the wellbore.

[0066] In some embodiments, for example, sensing of a decrease (e.g.
an absence) in torque being applied to the rotor is not indicative of rotor failure, such that further analytical evaluation is performed for determining a cause for the decrease (e.g. absence) in torque being applied.

[0067] The components of an ESP system 100 are arranged in series, with the motor 102 at the lower end of the ESP system 100 and the surface controls 108 at the top end (i.e. the surface 120). This arrangement allows the wellbore 118 to have a limited diameter while allowing the system to pump large volumes of reservoir fluid. This arrangement also allows the motor 102 and the pump 106 to operate on the same shaft (of the rotor).

[0068] ESPs, like other mechanical equipment, are prone to equipment failures and there are various problems which can impact the operation of the ESP
system. For example, components can fail physically due to wear over time or due to solids or gases within the wellbore. Problems with an ESP can arise in a variety of circumstances, such as when the ESP has low productivity, or when the ESP
trips due to a detected underload condition (i.e. the ESP is not lifting a sufficient volume of fluids).

Date Recue/Date Received 2022-01-21

[0069] Due to the limited diameter of wellbores in which ESP systems are deployed, it can be challenging to diagnose problems with the ESP as they arise.
The configuration of the wellbore mean that operators and engineers cannot observe downhole conditions and thus cannot diagnose problems with ESPs without the use of other equipment. Moreover, even if other equipment, such as downhole sensors, suggest certain problems with the ESP system, it is still challenging to determine the specific cause of the problems without observing the equipment.
Thus, it is often necessary to remove the equipment from the wellbore in order to evaluate and diagnose the cause of the problems.

[0070] In order to remove the ESP equipment from the wellbore, production from the wellbore must be stopped and the ESP system must be flushed of any fluid and removed from the wellbore in order to inspect the ESP system. This is a time-consuming and costly process, both in terms of the cost to remove the ESP
system from the wellbore, but also in the loss of productivity of the well. However, certain problems, such as gas-locking, can be remedied without the need to remove the equipment from the well. But, without being able to accurately diagnose the cause of the problems with the ESP system, the flushing and removal of the ESP
equipment is often required, even when the cause of the problems could have been solved without the removal of the ESP equipment.

[0071] A common issue with ESPs occurs when there is a rotor failure, for example a fractured or snapped shaft. In the present disclosure, a rotor failure can include cracking, fracturing, breaking or snapping of a shaft . It will be understood that a rotor failure can refer to any problem with the rotor that causes the rotor to disengage from the impellers. When the rotor fails in an ESP, the system loses productivity, but it is not clear, simply from the loss of productivity, that the issue is a rotor failure. In particular, when it is suspected that an ESP has a rotor failure, the ESP must be removed from the wellbore and inspected. Rotor failure generally occurs through two failure modes.

Date Recue/Date Received 2022-01-21

[0072] The first failure mode occurs through the flux of solids (e.g.
sand) and/or cold bitumen entering in the stages of the centrifugal pump. This typically results in a dramatic spike in torque and electric current for a short period of time (i.e. a few minutes or hours) before the shaft snaps. When the dramatic spike in torque and/or electric current is detected, the ESP can be programmed to trip in order to prevent the shaft from breaking. However, the rotor can still fail even with the ESP programmed to prevent rotor failures.

[0073] The second failure mode occurs due to a slow degradation of the rotor integrity. This degradation can occur when the motor and the pump have different outer diameters which results in shaft failure at the pump intake. The degradation can also occur due to low lubricity in the seal chamber section (i.e. low lubricity of the thrust bearing) which can cause excessive heat and eventual rotor failure at the thrust bearing.

[0074] Regardless of the failure mode of the rotor, pumps which use rotational energy transmitted from a motor to the pump can behave in a similar manner. With respect to ESPs, an indication that a rotor can have failed can be when the ESP trips. An ESP trip can be caused by a variety of conditions within the ESP and thus not every single ESP trip is indicative of a rotor failure.

[0075] When a possible rotor failure is detected, for example, when the pump has reduced or limited production, operators and engineers may know that there is a problem with the pumping system but cannot necessarily identify the source of the problem. Because identifying that a rotor has failed often requires the removal of the equipment from the installed location, operators and engineers will generally take time to troubleshoot the problem before resorting to the costly and time-consuming process of removing the pump from the installed location.

[0076] Pump parameters, such as operating temperatures, operating torques (torque being applied to the rotor), operating speeds (speed of the rotor), electrical currency and frequency inputs, intake and outlet pressures, are often monitored throughout the pump operation, especially in large scale productions such as the Date Recue/Date Received 2022-01-21 ESPs deployed in hydrocarbon wells. Pump parameters can be monitored using instrumentation such as instruments that can monitor temperature, pressure, torque, and speed, and that can be deployed downhole. The use of such instruments is often inadequate as the downhole conditions can affect the efficiency .. and accuracy of these instruments.

[0077] In ESP systems, certain parameters are monitored from the controller using the VFD, including the current and frequency applied to the motor, and the operating torque and speed. The present disclosure is directed to a method for identifying a rotor failure using measurement of torque being applied to the rotor and measurement of speed of the rotor.

[0078] In order to identify a rotor failure in a pump, rotor data, in particular, data pertaining to the speed of the rotor and data pertaining to torque being applied to the rotor, must be monitored throughout pump operation (such as, for example, while fluid (e.g. reservoir fluid) is being pumped by the pumping system (such as, for example, via a wellbore, from the subterranean formation to the surface). The monitored torque data includes measurements of the torque being applied to the rotor. Similarly, the monitored speed data includes measurements of the rotor speed as seen at the motor. In some embodiments, the torque data and the speed data are collected via the VFD (with a torque sensor and a speed sensor, respectively) and stored in the controller. This data can be monitored continuously, or in discrete intervals, for example on a minute-by-minute basis. Based on this monitored rotor data, it is possible to determine a shaft failure condition (i.e. a rotor failure).

[0079] Under normal operation, the torque being applied to the rotor and the speed of the rotor are directly proportional. In other words, when the speed of the is increased, the torque will also increase. Similarly, when the speed is decreased the torque will also decrease.

[0080] Table 1 below shows example data from an ESP operating under normal conditions. In this example, the ESP was tripped (i.e. taken out of Date Recue/Date Received 2022-01-21 operation) resulting in torque and speed measurements of zero. However, prior to the torque and speed measurements being zero, the torque and speed measurements showed very little variance and maintained the directly proportional relationship that is expected under normal operation.
Table 1: Example torque and speed measurements under normal ESP operation 1Speed 1Torque Current 1 1- 105G-8160-LM/HZ.CV 1105G-8160-105G-8160-108-May-20 00:0009 72.459938051 20.267982 29.701251 1- ....
108-May-20 02:00:00 72.560218811- 199977471 29.5994 t -1-=
108-May-20 04:00:00+
72.59999847' ZO.330084 30 1 08-May-20 06:00:00 72.63948059 19.884888 29.69835 108-May-20 08:00:00 72.7609787 20.446655 30 108-May-20 10:00:00 72.7000045: 20.025032 29 i 108-rviay-20 12:00:00 72.63848114 19.624931 30 ? 1 108-May-20 1400:00 72.5 19.938204 29.6996, 108-May-20 16:00001-7 92.59999847 1 .774216 29.80319 t -1-108-May-20 18:00:00+ 72.59999847' 20.243784 30 i- i- 1 -I-08-May-20 20:00:00i- 72.66119385-1- ' 20.20335G 30 -F. _ 108-May-20 22:00:004. 72.70000455 Z0.226774 29.30333 ! 09-May-20 00:00:001 7270000458 20.341854 30 I _ '-t-09-May-20 02:00:00 71300003052(299427 30 09-May-20 04:00:00 72.80000305 20.1i36647 29.31137 09-May-20 06:00:00 0 0 0 ! 091-May-20 08:00:00 0 0 0 i 09-May-20 10:00:001 0 0 0

[0081] Thus, one indication that the pump is not operating normally occurs when the speed and torque measurements change and do not reflect this directly proportional relationship. When the rotor fails, the rotor is no longer in contact with the impeller(s) and thus is not able to apply energy to the fluid. This results in a rapid and substantial decrease in torque while the speed of the rotor (as seen at the motor) remains substantially constant.

[0082] The torque that is being applied to the rotor, and the speed of the rotor, can be monitored throughout the operation of a pump. When the torque and speed measurements change over time, but remain proportional to one another, the pump is operating normally. When there is a relatively substantial decrease in the torque being applied to the rotor, while there is an absence of substantial Date Recue/Date Received 2022-01-21 variability in the speed of the rotor (e.g. the speed remains substantially constant), this can be an indication of rotor failure.

[0083] However, a relatively substantial decrease in the torque being applied to the rotor, in parallel with an absence of substantial variability in the speed of the rotor, does not necessarily signify a rotor failure.

[0084] When the rotor has failed, the rate at which torque decreases is relatively fast in comparison to other potential problems with the pump. As such, when the decreasing torque time interval is less than five minutes, it is indicative of the rotor having failed. When the decreasing torque time interval is greater than five minutes, it is likely that the decrease in torque is attributable to another cause, rather than rotor failure, such as, for example, gas lock. Under gas lock conditions, the applied torque can substantially decrease, while the speed remains substantially constant. However, the decrease in applied torque, under gas lock conditions, occurs over a much longer period of time versus the decrease in applied torque .. associated with a failed rotor condition.

[0085] Table 2, below, shows an example of torque and speed measurements obtained during a pump failure in which gas lock was the cause of the pump failure.
In this example, the torque measurement begins to decrease on March 26 at approximately 20:00 and reaches a substantially zero torque value on March 27, 2020 at approximately 8:00 (as can be seen in the outlined box). Although the gas lock condition shows a decrease in torque occurring while the speed remains substantially constant, it takes much longer, in this example between 10 and hours, for the ESP system to reach a torque value of zero. In contrast, when the rotor has failed, the torque decreases rapidly such that the torque will decrease to .. substantially zero within less than five (5) minutes.

Date Recue/Date Received 2022-01-21 Table 2: ESP failure in Gas Lock Condition !Speed 1Torque Current 1 !114G-8080-11J-11443-808ti114G-8080 t 25-Mar-20 18:00700t 83.900001513 14.97807 35.767031 25-Mar-20 20:00:00 83.80000305 76.:26 35.117991 :
25-Mar-70 27:00:00 83.80000305 81.91513 36.8829!
:
26-'Mr-2O 00:0000 83.81478119 75.12943 36..88242' _ -4-26-Mai-20 02:00:00 83.97161865 75.002331 34..88235!
_ _ +
26-Mar-20 04:00:00 S.3.84.325409 71.84753 33..46334!
I _ +
26-Mar-20 06:00:00 83.9283371 71.96714 34..88332 - _ --26-Mar-20 08:00:00 K.77157593' 82.912231 37. 4- 8822:1 1 _ _ -26-Mar-20 10:00:00 83.61373138! 73.7412.6 34.117631 26-Mar-20 12:00:00 83.784896851 74.11918 3536751!
-6 +
26-Mar-20 14:00:00 813.300003051 76.9531 361 -I- 6 +
j_26-Mar-20 16:00:00 83.771583561 0.5859.5 34.117491 26-Mar-20 18:00:00 83.843124391 76.80173 35.117661 F.26-Mar-20 20:00:00 83.70000458 i 79.49792. 361 ;
26-Mar-20 22:00:00 83.099998471 37.9675 26.116361 .....
27-Mar-2.0 00:00:00 83.02837372 28.08414 251 !
27-Mar-2002:O0:00 83.02842712 21.56345 241 ;
27-Mar-20 04:00:00 83.09999847! 22.11082 24.882771 27-Mar-2006d30:00 82.32839203 22.81944 23.882751 i 27-Mar-20 08:00:00 01 0 01 , 27-Mar-20 10:00:00 83.800003051 13.75489 23.76571!

[0086] In this regard, in order to identify whether the rotor of a pump has failed, the torque applied to the rotor, and the speed of the rotor (collectively, the monitored rotor data) are monitored during a monitoring time interval. A rotor failure condition can be identified based on the monitored rotor data.

[0087] In some embodiments, for example, the rotor failure condition is identified based on monitored rotor data which is representative of a substantial decrease in torque being applied to the rotor, while there is an absence of substantial variability in the speed of the rotor, and which is obtained over a relatively short time interval (a decreasing torque profile-defining time interval). In other words, a substantial decrease in the torque being applied to the rotor, occurring while there is an absence of substantial variability in the speed of the rotor, and occurring over a relatively short time interval, signifies a rotor failure. In some embodiments, for example, the decrease, in torque being applied to the rotor, is a decrease from a baseline applied torque.

Date Recue/Date Received 2022-01-21

[0088] Referring to Figure 2, in some embodiments, for example, the monitored rotor data, upon which the determination of a rotor failure condition is based, defines rotor failure-indicative data that is representative of a decreasing applied torque profile (ATP), of torque being applied to the rotor, while there is an absence of substantial variability, in the speed of the rotor, and spanning the decreasing torque profile-defining time interval (defined by the time interval between t1 and t2). The decreasing applied torque profile defines a substantial decrease in torque, being applied to the rotor, and the substantial decrease in torque is a decrease from a baseline applied torque (BAT), such that the decreasing applied torque profile defines the baseline applied torque (BAT).

[0089] In some embodiments, for example, the substantial decrease, in torque being applied to the rotor, is a decrease of at least 50%, such as, for example, at least 75%, such as, for example, at least 90%. In some embodiments, for example, the substantial decrease is 100%. Where the substantial decrease is 100%, the substantial decrease is with effect that there is an absence of torque being applied to the rotor (such that the measured torque has a zero value).

[0090] In some embodiments, for example, the decreasing torque profile-defining time interval is less than ten (10) minutes, such as, for example, less than five (5) minutes, such as, for example, less than one (1) minute.

[0091] In some embodiments, for example the absence of substantial variability, in the speed of the rotor, is an absence of variability of greater than ten (10) %, such as, for example, greater than five (5)%.

[0092] In some embodiments, for example, the baseline applied torque is at least 40 newton metres, such as, for example, at least 80 newton metres.

[0093] When the rotor failure condition is detected, operators and engineers can be notified that the pump must be removed from its installed location for maintenance or replacement. For example, the controller can send an alarm or notification to a computer, mobile device or other output device such that operators Date Recue/Date Received 2022-01-21 and engineers are aware that the problems with the pump are caused by a rotor failure. In some embodiments, the controller can be configured to shut down the pumping system in response to the detection that the rotor has failed. By shutting down the pumping system, other equipment or pump components can be protected from further damage caused by the failed rotor.

[0094] Referring to Figure 3, in some embodiments, for example, the rotor, briefly, experiences an increase in applied torque (i.e. torque-up) from an initial torque TQ1 to an increased torque TQ2, over the time interval defined between time TO and time Ti, and then the applied torque decreases, over the time interval defined between time Ti and T2, such the applied torque returns to TQ3, below its initial torque TQ1 (in some embodiments, for example, the decrease could be such that the applied torque returns to TQ1), while the rotor speed does not vary substantially. When this occurs, the decrease in applied torque, from the applied torque TQ2 to the applied torque TQ3, can be sufficiently substantial such that the system could, potentially, erroneously associate the monitored rotor data with a potential rotor failure, where the time interval defined between time Ti and time T2 is sufficiently short (e.g. less than ten (10) minutes). For example, if TQ2 is 50%
greater than TQ1, and TQ3 is 10 /0 less than TQ1, then the decrease from TQ2 to TQ3 is sufficiently substantial (the decrease is greater than 50%) to, potentially, erroneously associate the monitored rotor data with a potential rotor failure.

[0095] To mitigate versus this erroneous result, in some embodiments, for example, the monitored torque data, within a preceding time interval of five (5) minutes that immediately precedes the decreasing torque profile-defining time interval, defines torque data that is representative of a minimum applied torque, applied to the rotor, during the preceding time interval, and the baseline applied torque, defined by the decreasing applied torque profile, has a value that is less than or equal to that of the minimum applied torque. In this respect, the substantial decrease in torque, upon which the determination of a rotor failure condition is based, is measured from the "baseline applied torque", defined by the decreasing applied torque profile, and which has a value that is less than or equal Date Recue/Date Received 2022-01-21 to that of the "minimum applied torque", which is defined during the "preceding time interval".

[0096] In those cases where there is an increase in applied torque, due to torque-up, from TQ1 to TQ2, and a subsequent decrease in applied torque to TQ3, the decrease in applied torque is not measured from TQ2, as the baseline applied torque, defined by the decreasing applied torque profile, from which the decrease is measured, would be defined by TQ1 at time T1A, and the decrease in applied torque would be measured by subtracting TQ3 from TQ1, the baseline applied torque (BAT), as opposed to subtracting TQ3 from TQ2, and the decrease in torque may not be sufficient to be indicative of a rotor failure condition. For example, and referring to Figure 4, if TQ2 is 50% greater than TQ1, and TQ3 is 10% less than TQ1, then the decrease from TQ1 to TQ3 is not sufficiently substantial (the decrease is less than 50%) to erroneously associate the monitored rotor data with a potential rotor failure (irrespective of whether the time interval defined between T1A and T2 is sufficiently short, as defined above), even though the decrease from TQ2 to TQ3 is greater than 50%, as most of the profile, between TQ2 and TQ3, does not qualify as a "decreasing applied torque profile". This is because most of the profile, between TQ2 and TQ3, is defined before time T1A, which means that only the monitored rotor data beyond time T1A (i.e. that portion of the profile ATP1) is eligible for consideration to identify a rotor failure condition, as the decrease in applied torque before time T1A is not "a decrease from the baseline applied torque", as the baseline applied torque is measured as being "a value that is less than or equal to that of the minimum applied torque". Alternatively, and referring to Figure 5, in those cases where TQ3 is more than 50% less than TQ1, and the time interval defined between time T1A and T2 is sufficiently short (e.g.
less than ten (10) minutes), then the decrease is sufficiently substantial (the decrease is greater than 50%) to be indicative of a rotor failure condition.

[0097] Although the present disclosure describes methods and processes with steps in a certain order, one or more steps of the methods and processes can be Date Recue/Date Received 2022-01-21 omitted or altered as appropriate. One or more steps can take place in an order other than that in which they are described, as appropriate.

[0098] Although the present disclosure is described, at least in part, in terms of methods, a person of ordinary skill in the art will understand that the present disclosure is also directed to the various components for performing at least some of the aspects and features of the described methods, either by way of hardware components, software or any combination of the two. Accordingly, the technical solution of the present disclosure can be embodied in the form of a software product. A suitable software product can be stored in a pre-recorded storage device or other similar non-volatile or non-transitory computer readable medium, including DVDs, CD-ROMs, USB flash disk, a removable hard disk, or other storage media, for example. The software product includes instructions tangibly stored thereon that enable a processing device (e.g., a personal computer, a server, or a network device) to execute examples of the methods disclosed herein. In general, the software improves the operation of the hardware in one or more ways.

[0099] The present disclosure can be embodied in other specific forms without departing from the subject matter of the claims. The described example implementations are to be considered in all respects as being only illustrative and not restrictive. Selected features from one or more of the above-described implementations can be combined to create alternative implementations not explicitly described, features suitable for such combinations being understood within the scope of this disclosure.

Date Recue/Date Received 2022-01-21

Claims (70)

WHAT IS CLAIMED IS:

1. A method for identifying a failure of a rotor of a pumping system, the pumping system comprising a pump connected to a drive with the rotor, comprising:
monitoring torque being applied to the rotor and monitoring speed of the rotor such that monitored rotor data is obtained; and determining if a rotor failure condition exists based on the monitored rotor data.

2. The method as claimed in claim 1, wherein existence of the rotor failure condition is determined when the monitored rotor data defines rotor-failure indicative data that spans a time interval of less than ten (10) minutes and is representative of a decrease of at least 50% in torque being applied to the rotor while there is an absence of variability in the speed of the rotor of greater than 10%.

3. The method as claimed in claim 2, wherein the decrease in applied torque is a decrease of 100%, such that the decrease is with effect that there is an absence of torque being applied to the rotor.

4. The method as claimed in claim 2 or 3, wherein the decrease is a decrease from a baseline applied torque, and the baseline applied torque is at least 40 newton metres.

5. The method as claimed in any one of claims 2 to 4, wherein the time interval, over which the rotor-failure indicative data spans, is less than five (5) minutes.

6. The method as claimed in any one of claims 2 to 5, wherein the absence of variability in the speed of the rotor is an absence of variability of greater than 5%.

7. The method as claimed in claim 1, wherein existence of the rotor failure condition is determined when the monitored rotor data defines rotor failure-indicative data that spans a decreasing torque profile-defining time interval and has a duration of less than ten (10) minutes and is representative of a decreasing applied torque profile of torque being applied to the rotor while there is an absence of variability in the speed of the rotor of greater than 10%, and the decreasing applied torque profile defines a decrease in torque, being applied to the rotor, of at least 50%.

8. The method as claimed in claim 7, wherein the decrease in torque is a decrease of 100%, such that the decrease is with effect that there is an absence of torque being applied to the rotor.

9. The method as claimed in claim 7 or 8, wherein the decrease in torque is a decrease from a baseline applied torque, such that the decreasing applied torque profile defines the baseline applied torque, and the baseline applied torque is at least 40 newton metres.

10. The method as claimed in any one of claims 7 to 9, wherein the decreasing torque profile-defining time interval is less than five (5) minutes.

11. The method as claimed in any one of claims 7 to 10, wherein the absence of variability in the speed of the rotor is an absence of variability of greater than 5%.

12. The method as claimed in claim 7, wherein the monitored rotor data comprises monitored torque data, the decrease in applied torque is a decrease from a baseline applied torque, such that the decreasing applied torque profile defines the baseline applied torque, the monitored torque data, within a preceding time interval of five (5) minutes that immediately precedes the decreasing torque profile-defining time interval, defines torque data that is representative of a minimum-applied torque applied to the rotor during the preceding time interval, and the baseline applied torque has a value that is less than or equal to that of the minimum-applied torque.

13. The method as claimed in claim 12, wherein the decrease in applied torque is a decrease of 100%, such that the decrease is with effect that there is an absence of torque being applied to the rotor.

14. The method as claimed in claim 12 or 13, wherein the baseline applied torque is at least 40 newton metres.

15. The method as claimed in any one of claims 12 to 14, wherein the decreasing torque profile-defining time interval is less than five (5) minutes.

16. The method as claimed in any one of claims 12 to 15, wherein the absence of variability in the speed of the rotor is an absence of variability of greater than 5%.

17. The method as claimed in any one of claims 1 to 16, wherein the pump is a centrifugal pump.

18. The method as claimed in claim 17, wherein the pump is an electrical submersible pump.

19. The method as claimed in any one of claims 1 to 18, wherein the pump comprises at least one impeller mounted on an impeller shaft portion of the rotor, and the rotor failure condition comprises a failure of the impeller shaft portion.

20. The method as claimed in claim 19, wherein the failure of the impeller shaft portion includes a snapped shaft.

21. The method as claimed in any one of claims 1 to 20, wherein the drive comprises an electric motor.

22. The method as claimed in any one of claims 1 to 20, wherein the monitoring of the applied torque is effectuated with a torque sensor, and the monitoring of the speed is effectuated with a speed sensor.

23. The method as claimed in claim 22, wherein the drive comprises an electric motor.

24. The method as claimed in claim 23, wherein the drive further comprises a variable frequency drive disposed in signal communication with the motor, and the variable frequency drive comprises the torque sensor and the speed sensor.

25. The method as claimed in any one of claims 1 to 24, wherein the monitored rotor data is obtained during pumping of fluid by the pumping system.

26. The method as claimed in any one of claims 1 to 25, further comprising, in response to determining that a rotor failure condition exists, suspending the rotation of the rotor.

27. The method as claimed in any one of claims 1 to 26, further comprising, in response to determining that a rotor failure condition exists, presenting an indication of the rotor failure condition via an output device.

28. The method as claimed in one of claims 1 to 25, wherein, in response to the monitoring, sensing an absence of torque being applied to the rotor in the absence of a determination of an existence of a rotor failure condition, and performing a further analytical evaluation for determining a cause for the sensed absence of torque.

29. The method as claimed in any one of claims 1 to 24, wherein the pumping system is disposed within a wellbore extending into a subterranean formation from a surface.

30. The method as claimed in claim 29, wherein the monitored rotor data is obtained during pumping of fluid by the pumping system, and the pumping comprises pumping of reservoir fluid from the subterranean formation to the surface.

31. The method as claimed in claim 30, wherein the reservoir fluid comprises oil.

32. The method as claimed in any one of claims 29 to 31, further comprising, in response to determining that a rotor failure condition exists, suspending rotation of the rotor.

33. The method as claimed in claim 32, further comprising, after the suspending of the rotation of the rotor, removing the pumping system from the wellbore.

34. The method as claimed in any one of claims 29 to 32, further comprising, in response to determining that a rotor failure condition exists, presenting an indication of the rotor failure condition via an output device.

35. The method as claimed in one of claims 29 to 31, wherein, in response to the monitoring, sensing an absence of torque being applied to the rotor in the absence of a determination of an existence of a rotor failure condition, and performing a further analytical evaluation for determining a cause for the sensed absence of torque.

36. A system for identifying a failure of a rotor of a pumping system comprising:
one or more processor devices and one or more memories storing machine-executable instructions which, when executed by the one or more processor devices, cause the system to perform the method of any one of claims 1 to 35.

37. A system for identifying a failure of a rotor of a pumping system, the pumping system comprising a pump connected to a drive with the rotor, the system comprising:
a torque sensor, a speed sensor, one or more processor devices, and one or more memories storing machine-executable instructions, which when executed by the one or more processor devices, cause the system to:
monitor torque being applied to the rotor, using the torque sensor, and monitor speed of the rotor, using the speed sensor, such that monitored rotor data is obtained, and determine if a rotor failure condition exists, based on the monitored rotor data.

38. The system as claimed in claim 37, wherein existence of the rotor failure condition is determined when the monitored rotor data defines rotor-failure indicative data that spans a time interval of less than ten (10) minutes and is representative of a decrease of at least 50% in torque being applied to the rotor while there is an absence of variability in the speed of the rotor of greater than 10%.

39. The system as claimed in claim 38, wherein the decrease in applied torque is a decrease of 100%, such that the decrease is with effect that there is an absence of torque being applied to the rotor.

40. The system as claimed in claim 38 or 39, wherein the decrease is a decrease from a baseline applied torque, and the baseline applied torque is at least 40 newton metres.

41. The system as claimed in any one of claims 38 to 40, wherein the time interval, over which the rotor-failure indicative data spans, is less than five (5) minutes.

42. The system as claimed in any one of claims 38 to 41, wherein the absence of variability in the speed of the rotor is an absence of variability of greater than 5%.

43. The system as claimed in claim 37, wherein existence of the rotor failure condition is determined when the monitored rotor data defines rotor failure-indicative data that spans a decreasing torque profile-defining time interval and has a duration of less than ten (10) minutes and is representative of a decreasing applied torque profile of torque being applied to the rotor while there is an absence of variability in the speed of the rotor of greater than 10%, and the decreasing applied torque profile defines a decrease in torque, being applied to the rotor, of at least 50%.

44. The system as claimed in claim 43, wherein the decrease in torque is a decrease of 100%, such that the decrease is with effect that there is an absence of torque being applied to the rotor.

45. The system as claimed in claim 43 or 44, wherein the decrease in torque is a decrease from a baseline applied torque, such that the decreasing applied torque profile defines the baseline applied torque, and the baseline applied torque is at least 40 newton metres.

46. The system as claimed in any one of claims 43 to 45, wherein the decreasing torque profile-defining time interval is less than five (5) minutes.

47. The system as claimed in any one of claims 43 to 46, wherein the absence of variability in the speed of the rotor is an absence of variability of greater than 5%.

48. The system as claimed in claim 43, wherein the monitored rotor data comprises monitored torque data, the decrease in applied torque is a decrease from a baseline applied torque, such that the decreasing applied torque profile defines the baseline applied torque, the monitored torque data, within a preceding time interval of five (5) minutes that immediately precedes the decreasing torque profile-defining time interval, defines torque data that is representative of a minimum-applied torque applied to the rotor during the preceding time interval, and the baseline applied torque has a value that is less than or equal to that of the minimum-applied torque.

49. The system as claimed in claim 48, wherein the decrease in applied torque is a decrease of 100%, such that the decrease is with effect that there is an absence of torque being applied to the rotor.

50. The system as claimed in claim 48 or 49, wherein the baseline applied torque is at least 40 newton metres.

51. The system as claimed in any one of claims 48 to 50, wherein the decreasing torque profile-defining time interval is less than five (5) minutes.

52. The system as claimed in any one of claims 48 to 51, wherein the absence of variability in the speed of the rotor is an absence of variability of greater than 5%.

53. The system as claimed in any one of claims 37 to 52, wherein the pump is a centrifugal pump.

54. The system as claimed in claim 53, wherein the pump is an electrical submersible pump.

55. The system as claimed in any one of claims 37 to 54, wherein the pump comprises at least one impeller mounted on an impeller shaft portion of the rotor, and the rotor failure condition comprises a failure of the impeller shaft portion.

56. The system as claimed in claim 55, wherein the failure of the impeller shaft portion includes a snapped shaft.

57. The system as claimed in any one of claims 37 to 56, wherein the drive comprises an electric motor.

58. The system as claimed in claim 57, wherein the drive further comprises a variable frequency drive disposed in signal communication with the motor, and the variable frequency drive comprises the torque sensor and the speed sensor.

59. The system as claimed in any one of claims 37 to 58, wherein the monitored rotor data is obtained during pumping of fluid by the pumping system.

60. The system as claimed in any one of claims 37 to 59, wherein, in response to determining that a rotor failure condition exists, causing the system to suspend the rotation of the rotor.

61. The system as claimed in any one of claims 37 to 60, further comprising an output device, wherein, in response to determining that a rotor failure condition exists, causing the system to present an indication of the rotor failure condition to the output device.

62. The system as claimed in any one of claims 37 to 59, wherein, in response to the monitoring, sensing an absence of torque being applied to the rotor, using the torque sensor, in the absence of a determination of an existence of a rotor failure condition, and performing a further analytical evaluation for determining a cause for the sensed absence of torque.

63. The system as claimed in any one of claims 37 to 58, wherein the pumping system is disposed within a wellbore extending into a subterranean formation from a surface.

64. The system as claimed in claim 63, wherein the monitored rotor data is obtained during pumping of fluid by the pumping system, and the pumping comprises pumping of reservoir fluid from the subterranean formation to the surface.

65. The system as claimed in claim 64, wherein the reservoir fluid comprises oil.

66. The system as claimed in any one of claims 63 to 65, further comprising, in response to determining that a rotor failure condition exists, causing the system to suspend rotation of the rotor.

67. The system as claimed in claim 66, further comprising, after the suspending of the rotation of the rotor, the pumping system is removed from the wellbore.

68. The system as claimed in any one of claims 64 to 66, further comprising an output device, wherein, in response to determining that a rotor failure condition exists, causing the system to present an indication of the rotor failure condition to the output device.

69. The system as claimed in any one of claims 64 to 67, wherein, in response to the monitoring, sensing an absence of torque being applied to the rotor, using the torque sensor, in the absence of a determination of an existence of a rotor failure condition, and causing the system to perform a further analytical evaluation for determining a cause for the sensed absence of torque.

70. A non-transitory computer-readable medium storing machine-executable instructions which, when executed by one or more processors, cause the processor to perform the steps of the method of any one of claims 1 to 35.