The present application is a U.S. National Stage Application of International Application No. PCT/US2017/019471 filed Feb. 24, 2017, which is incorporated herein by reference in its entirety for all purposes.
The present disclosure relates generally to high pressure pump power ends, and more particularly, to systems and methods for monitoring connecting rod bearings and crosshead bearings in a high pressure pump power end.
Variable stroke piston-type and plunger-type positive displacement pumps are commonly employed in oil and gas production fields for operations such as drilling and well servicing. For instance, one or more reciprocating pumps may be employed to pump fluids into a wellbore in conjunction with activities including fracturing, acidizing, remediation, cementing, and other stimulation or servicing activities. Due to the harsh conditions associated with such activities, many considerations are generally taken into account when designing a pump for use in oil and gas operations.
A typical positive displacement pump will include at least one piston or plunger arranged to move in reciprocating fashion within a piston cylinder by means of a conventional crankshaft and connecting rod assembly. One end of the connecting rod is coupled to the crankshaft via a bearing, while the opposite end of the connecting rod is coupled to a crosshead via another bearing. Lubrication of the power end components of the positive displacement pump is generally provided to reduce friction, reduce friction-related heat, remove particulate matter, and, thereby, improve the life and/or minimize failure of large pump system components.
Unfortunately, undetected damage to the bearings in the pump power end can cause the connecting rod to fail, which can then lead to a worsening situation in the pump until a catastrophic failure of the pump power end occurs. Fixing the pump power end after unexpected failures such as this can be expensive and time consuming, as the pump system may be shut down suddenly and broken internal components of the pump may breach the pump power end housing. It is recognized that reliable methods for identifying a failing bearing on a pump power end connecting rod or crosshead are desired.
For a more complete understanding of the present disclosure and its features and advantages, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which:
Illustrative embodiments of the present disclosure are described in detail herein. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation specific decisions must be made to achieve developers' specific goals, such as compliance with system related and business related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of the present disclosure. Furthermore, in no way should the following examples be read to limit, or define, the scope of the disclosure.
The terms “couple” or “couples” as used herein are intended to mean either an indirect or a direct connection. Thus, if a first device couples to a second device, that connection may be through a direct connection, or through an indirect mechanical or electrical connection via other devices and connections. The term “fluidically coupled” or “in fluid communication” as used herein is intended to mean that there is either a direct or an indirect fluid flow path between two components.
The present disclosure is directed to a system and method for eliminating catastrophic pump power end failures due to semi journal bearing failures on a connecting rod. Typical existing methods of bearing condition monitoring revolve around taking vibration measurements and comparing them to a baseline. Unfortunately, such methods have proven difficult for use on reciprocating machinery. This is because typical vibration based condition monitoring techniques are not as effective with high mass, low speed machinery like reciprocating pump power ends.
To overcome these drawbacks, the disclosed system and method may predict catastrophic pump power end failures due to connecting rod bearing failures by the use of temperature measurements, as opposed to vibration measurements. While temperature measurements have been used to determine bearing health in general, it is challenging to apply temperature-based bearing monitoring techniques to the area of connecting rod and crosshead bearings of a pump. This is because the connecting rod and the crosshead are each in constant motion within the pump power end housing.
One option for providing temperature measurements for evaluating bearing health in the pump power end environment is to mount temperature sensors directly onto the connecting rod (and/or crosshead). These temperature sensors may be connected to a monitoring system outside the pump by either flexible wires that can withstand bending due to movement of the internal connecting rod/crosshead or some sort of wireless communication system. If wireless communication is used, the temperature sensors may be supplied with power via a power source inside the pump power end. In some embodiments, for example, the temperature sensors may be powered by pump motion or other mechanical means of power generation.
Another option for providing temperature measurements for evaluating bearing health in a pump power end is through the use of non-contact temperature measurement. For example, the disclosed systems may provide non-contact temperature measurements in the form of infrared sensor measurements or thermal imaging. The system may employ an infrared non-contact temperature sensor aimed directly at all points on the connecting rod or crosshead where the temperature is to be determined.
These and other types of temperature measurement systems and methods may be utilized in the pump power end to take temperature measurements of the connecting rod or crosshead near the bearing connections. The detected temperature measurements may then be communicated from the internal temperature sensors to a controller located external to the pump power end. The controller may read, store, and compare the various temperature sensor data, and the controller may output an alert to an operator or shut down the pump upon detecting a temperature that exceeds a predetermined threshold. That way, the system can shut down the pump before any catastrophic pump failure occurs in response to damage to one or more bearings at the connection rod or crosshead. An operator would then simply provide routine maintenance to replace pump system bearings or other small components, without the costly and time consuming repairs associated with catastrophic pump end failure. In addition, in embodiments where temperature measurements are provided to the controller continuously over a long period of time, the temperature measurements may be stored and monitored to track the decay of pump equipment over time.
Turning now to the drawings,
The system 10 may utilize a temperature sensor assembly 18 to detect the temperature of one or more bearings disposed in a power end 14 of the pump 12. The bearings may be located at the interface between the crankshaft and the connecting rod or at the interface between the connecting rod and the crosshead. The temperature sensor assembly 18 may include one or more temperature sensors, which may be contact sensors or non-contact sensors, disposed in the power end 14 to detect a temperature at the desired bearing locations. Examples of various types of temperature sensor assemblies 18 that may be utilized in the disclosed system 10 are described in detail below with reference to
As illustrated, the temperature sensor assembly 18 may be communicatively coupled to a controller 20 located external to a housing 22 of the pump power end 14. The temperature sensor assembly 18 may be at least partially disposed within the housing 22 of the pump end 14 so that the temperature sensor is able to take temperature measurements of the bearing components enclosed within the power end housing 22 and to communicate the temperature measurements to the controller 20 disposed outside the housing 22. The system 10 may further include a data acquisition (DAQ) system 24 coupled between the temperature sensor assembly 18 and the controller 20. In some instances, the DAQ system 24 may be used to communicate sensor signals from multiple distributed sensor assemblies on the pump 12 or a plurality of pumps 12 to the controller 20. Cabling 26 (or wireless communication techniques) may be used between the controller 20, DAQ system 24, and temperature sensor assembly 18 in the pump power end 14 to communicate data, control signals, and power between the system components.
The controller 20 utilizes at least a processor component 28 and a memory component 30 to monitor and/or control various operations at the pump 12. For example, one or more processor components 28 may be designed to execute instructions encoded into the one or more memory components 30. Upon executing these instructions, the processors 28 may analyze signals received from the temperature sensor assembly 18 to monitor the health of bearings disposed in the pump power end 14. The processors 28 may output control signals to a user interface 32 in response to certain signals received from the temperature sensor assembly 18 and/or DAQ system 24. For example, the processor 28 may compare the detected temperature measurements received at the controller 20 to a predetermined threshold and, if the detected temperature exceeds the threshold, the processor 28 may output a signal to the user interface 32 to output an alert to an operator. In some embodiments, the processor 28 may output a control signal to the power end 14 to shut off pump operation if a detected temperature signal exceeds the temperature threshold indicating that a bearing is failing. The controller 20 may be communicatively coupled to a database 34, as shown, and the processor 28 may send temperature measurement signals to the database 34 for storage throughout pump operation. The processor 28 may perform various trend analyses on the temperature measurement data stored in the database 34 over a period of time in which the pump 12 is in operation.
Having now described a general overview of the system 10 for monitoring bearing health using a temperature sensor assembly 18 disposed in the pump power end 14, a more detailed description of an example temperature sensor assembly 18 will be provided.
Bearings are located on the first end 80 of the connecting rod 76 to support the connecting rod 76 in a desired plane of movement between the crankshaft 74 and the crosshead 78 while the crankshaft 74 rotates about a shaft axis 84 (parallel to Z-axis). Bearings are similarly located on the crosshead 78 to support the rotating second end 82 of the connecting rod 76 as the crosshead 78 moves in a direction of the X-axis. As described above, either of these sets of bearings may become damaged during regular use of the pump power end 14 and, if not fixed or replaced in a reasonable amount of time, may lead to larger system pump failures.
Abnormally high temperatures of the first end 80 of the connecting rod 76 can indicate that a connecting rod bearing at the interface of the connecting rod 76 and the crankshaft 74 is damaged. Similarly, high temperatures of the crosshead 78 can indicate that a crosshead bearing at the interface of the connecting rod 76 and the crosshead 78 is damaged. The temperature sensor assembly 18 may be disposed in the power end 14 to detect a temperature at the first end 80 of the connecting rod 76, the crosshead 78, or both.
In the illustrated embodiment, the temperature sensor assembly 18 includes a non-contact temperature sensor 70, which is mounted on the housing 22 of the power end 14. The non-contact temperature sensor 70 may include a passive infrared sensor having an infrared receiver used to detect electromagnetic energy emitted from a target component (e.g., connecting rod 76 or crosshead 78) at infrared wavelengths. In other embodiments, the non-contact temperature sensor 70 may include an infrared sensor having a transmitter for transmitting infrared or other wavelength energy toward the target component (e.g., connecting rod 76 or crosshead 78) and a receiver for detecting electromagnetic energy reflected back from the target component.
As shown, the non-contact temperature sensor 70 may be disposed on and pointed inward from the housing 22 to detect a temperature of the connecting rod 76, which is indicative of the temperature of the bearings at the interface of the first end 80 of the connecting rod 76 and the crankshaft 74. In other embodiments, the non-contact temperature sensor 70 may be positioned to detect a temperature of the crosshead 78, which is indicative of the temperature of the bearings at the interface of the crosshead 78 and the second end 82 of the connecting rod 76. In still other embodiments, the temperature sensor assembly 18 may include two non-contact sensors 70, each mounted to the housing 22, with one positioned to take temperature measurements of the connecting rod bearings and the other positioned to take temperature measurements of the crosshead bearings.
Since it utilizes one or more non-contact sensors 70 such as infrared sensors mounted directly to the pump housing 22, the temperature sensor assembly 18 may be relatively easy to install onto existing pump power ends 14. That is, one or more infrared or other non-contact temperature sensors 70 may be simply inserted into an opening formed in the housing 22, calibrated for taking the desired temperature measurements, and communicatively coupled to the DAQ system (e.g., 24 of
In the context of using one or more non-contact sensors 70, the sensors may not directly take measurements of the actual temperature of the internal components in the power end 14. Instead, the sensors 70 may detect electromagnetic energy at infrared or other frequencies emitted or reflected from the target component (e.g., connecting rod or crosshead) and send the data to the controller 20 for determination of an approximate temperature of the component based on the heat it is radiating. Thus, the controller 20 of
Turning back to
Some lubricating oils may be more transparent at certain energy wavelengths than others. As such, it may be desirable to calibrate or tune the wavelength of energy transmitted or received by the non-contact sensor 70 based on the particular oil being used. That way, the non-contact sensor 70 outputs an accurate measurement of the temperature of the connecting rod 76 or crosshead 78 for the particular pump. In some embodiments, a target material 150 may be disposed on the connecting rod 76 (or crosshead 78) to provide a stronger target for the non-contact sensor 70. For example, the target material 150 may be a certain material that emits or reflects energy at wavelengths that can easily pass through the oil layer on the connecting rod 76 or crosshead 78 for detection by the non-contact sensor 70.
In some instances, the non-contact sensor 70 may just detect the energy reflected or emitted from the oil layer that is indicative of the temperature of the oil (as opposed to the exact temperature of the connecting rod 76 or crosshead 78). However, the energy detected by the non-contact sensor 70 may still offer an effective approximation of the temperature of the connecting rod 76 or crosshead 78 under the oil. Additionally, by detecting the energy radiating from the oil, the non-contact sensor 70 may provide measurements to the controller that are useful in determining when the temperature of the connecting rod 76 or the crosshead 78 has exceeded a normal operating threshold. This is because once the temperature of the connecting rod 76 or crosshead 78 gets too high, the layer of oil becomes less effective or ineffective at lubricating the components. The increase in temperature may change the consistency of the oil layer and, as a result, the amount of energy radiating therefrom that is detected by the sensor 70.
In embodiments of the pump power end 14 with the temperature sensor assembly 18 having a non-contact temperature sensor 70, as described in reference to
In other embodiments, the pump power end 14 may utilize a temperature sensor assembly 18 with just one temperature sensor (e.g., non-contact temperate sensor 70) and a position sensor 170, as shown in
All of the temperature sensor assemblies 18 for a given pump power end 14 may be communicatively coupled to the DAQ system 24 and/or the controller 20. The controller 20 may compare the temperature readings across each of the temperature sensor assemblies 18 in a given power end 14. In addition, all of the temperature sensor assemblies 18 used on the multiple pumps 12 may be communicatively coupled to the DAQ system 24 and the controller 20, as shown in
While temperature sensor assemblies 18 utilizing one or more non-contact temperature sensors are described above, other embodiments of the temperature sensor assemblies 18 may be utilized in the disclosed system 10.
In the temperature sensor assemblies 18 of
The transmitter 232 and the temperature sensor 230 may be selectively coupled to the battery 392 via the mechanical switch device 390. The mechanical switch device 390 may operate similar to a thermostat such that when the connecting rod 76 (or crosshead) reaches a certain temperature, it moves a lever to electrically couple the temperature sensor 230 and the transmitter 232 to the battery 392. That way, the temperature sensor assembly 18 may only provide temperature measurements to the outside controller once the internal power end temperatures are within a certain range where bearing operation may be compromised. When a bearing is replaced or other maintenance is performed on the pump power end 14, an operator may reset the mechanical switch device 390 to decouple the sensor 230 and transmitter 232 from the battery 392. That way, a simple coin operated battery 392 may be used to provide sensing power in the pump end 14 throughout the lifecycle of the pump. Multiple temperature sensors 230 and associated transmitters 232, receivers 234, mechanical switch devices 390, and batteries 392 may be utilized in the pump power end 14 and positioned such that they take measurements of different points around the connecting rod 76 (or crosshead) for redundancy.
Although the present disclosure and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the disclosure as defined by the following claims.
Filing Document | Filing Date | Country | Kind |
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PCT/US2017/019471 | 2/24/2017 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
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WO2018/156152 | 8/30/2018 | WO | A |
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Number | Date | Country | |
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20190345921 A1 | Nov 2019 | US |