Patent Application
20180202423
This patent disclosure relates generally to a system and method for detecting wear on valves included in a fluid pump and, more particularly, to monitoring valve wear in pumps that may be used in hydraulic fracturing or “fracking” operations.
Hydraulic fracturing, or “fracking,” is a technique used in the oil, gas industry to recover oil and gas by directing pressurized fracking fluid into a downhole wellbore for inducing cracks in deep rock formations underground to release oil and/or gas therein, and through which the oil and gas can readily flow when the pressurized fluid is removed. The pumps used in fracking operations to pressurize and direct the fracking fluids are typically large positive displacement pumps capable of generating tremendously high pressures. Because the fracking fluid is abrasive and because of the high pressures utilized in fracking operations, the internal components of the pump are subject to wear and possible failure. Accordingly, operation of the pumps is monitored in order to conduct preventative maintenance when necessary and avoid disrupting the fracking operation. By way of reference, U.S. Patent Publication No. 9,260,959 discloses a system for controlling and monitoring operation of a hydraulic fracking pump and related equipment.
The disclosure describes, in one aspect, a pump for pumping fluid, for example, in a hydraulic fracking operation. The pump includes an intake manifold, a discharge outlet, and a plurality of pumping chambers in fluid communication with the intake manifold and the discharge outlet to receive and discharge fluid. To detect a discharge pressure from the plurality of pumping chambers, a pressure sensor may be disposed in the discharge outlet. The pump further may be associated with a logic device configured to receive discharge pressure data from the pressure sensor, to analyze the discharge pressure data verses time, and to determine the peak-to-peak amplitude of the discharge pressure verses time to detect a discharge pressure spike.
In another aspect, the disclosure describes a method of operating a pump. The method includes receiving electronic signals indicative of a discharge pressure associated with the discharge of fluid from the pump. A logic device, dedicated in part to the analysis of the discharge pressure, analyzes the discharge pressure verses time. The logic device further determines a high peak-to-peak amplitude of the discharge pressure to detect a discharge pressure spike in the discharge pressure. According to the method, the discharge pressure spike may be associated with uncharacteristic operation of a discharge valve or a suction valve associated with the pump.
In another aspect, the disclosure describes a system for monitoring operation of a pump discharging fluid. The system includes a pressure sensor disposed in the discharge outlet to measure a discharge pressure from a plurality of pumping chambers discharging fluid to the discharge outlet. The system also includes a logic device communicating with the sensor to receive discharge pressure data reflecting the discharge pressure. The logic device may be configured to determine a peak-to-peak amplitude associated with the discharge pressure and compare the peak-to-peak amplitude with a discharge pressure threshold. If high peak-to-peak amplitude exceeds the discharge pressure threshold, the logic device may issue an alarm.
This disclosure relates a pump that may be used, for example, for performing a hydraulic fracking operation to recover oil and/or natural gas from below the surface of the earth by directing high-pressure fracking fluid into a downhole wellbore to induce cracks in the rock formations below. Referring to
The fracking machine 100 can include as a power source or prime mover such as an internal combustion engine 102 like a diesel-burning compression ignition engine the combusts diesel fuel stored in one or more tanks 104 to generate mechanical or motive power. However, other examples of prime movers include gasoline-burning spark ignition engines, gas-burning turbines, and the like. To pressurize the fracking fluid, the internal combustion engine 102 is operatively coupled via drivetrain components 105 such as a crankshaft, transmission, and driveshaft to a positive displacement hydraulic pump 106, which may connected to hoses, pipes, and the like to receive low pressure fluid from storage tanks and discharge high pressure fluid to the wellhead. To cool the internal combustion engine 102, the fracking machine 100 can include a radiator 108 that circulates coolant to and from the engine thereby transferring the generated heat to the environment. The components of the fracking machine 100 may be disposed on a mobile trailer 110 supported on wheels 112 to move the fracking machine to different locations; however, in other embodiments, the fracking machine 100 can be stationary.
Referring to
To receive the low-pressure fracking fluid, the pumping unit 124 can communicate with an inlet manifold 130 disposed generally underneath the pumping unit 124. To distribute fluid to the individual pumping chambers 126, the inlet manifold 130 can include a fluid rail 132 having a common inlet port 134 that can be attached to a hose or other piping and a plurality of inlet lines 136 that lead to the pumping chambers 126. To discharge the fracking fluid pressurized in the pumping chambers 126, the pumping unit 124 can include a common discharge outlet 138 disposed on the top of the pumping unit and that communicates with each of the pumping chambers 126. The discharge outlet 138 can connect to high-pressure lines or the like that direct pressurized fluid to the wellhead. It should be appreciated that, in other embodiments, different configurations for receiving and discharging fracking fluid to and from the pumping unit 124, including different number or locations of discharge outlets 138, are contemplated.
To monitor the fluid pressure and/or flow rate of fracking fluid into and out of the pumping unit 124, one or more pressure sensors can be operatively associated with the pump 106. For example, a first pressure sensor 140 can be disposed in or proximate to the discharge outlet 138 to measure the fluid pressure being discharged from the pumping unit 124. Because it is arranged in the discharge outlet 138, the first pressure sensor 140 may measure the combined discharge pressure from each of the plurality of pumping chambers 126. In other embodiments, a plurality of first pressure sensors 140 can be associated with each of the individual pumping chambers 126 and the output of each sensor combined to determine a common discharge pressure. The first pressure senor 140 can operate on electrical principles, mechanical principles, electromechanical principles, piezoelectrics, magnetic, or utilize any other suitable technologies or combinations thereof to measure the fluid force being commonly discharged from the combination of pumping chambers 126. The first pressure sensor 140 can read the high-pressure fracking fluid being discharged from the pump 106 in any suitable units such as, for example, kilopascals, pounds per square inch (PSI), bars, or the like. The first pressure sensor 140 can transmit in real time data regarding the discharge pressure as electrical or electronic signals in either analog or digital format. Additionally, to measure the pressure of the low-pressure fracking fluid being received into the pumping unit 124, a second pressure sensor 142 can be disposed in the inlet manifold 130.
Referring to
During the pumping cycle, the piston 160 is retracted in the cylinder bore 154 creating an internal vacuum in the pumping chamber 126. The vacuum causes the suction valve 162 to lift into the suction chamber 152 thereby opening the suction chamber 152 to receive fracking fluid. Because of its orientation, however, the vacuum draws the discharge valve 164 against its respective valve seat 166 thereby keeping the discharge chamber 156 closed. When the piston 160 reciprocally changes direction and extends into the cylinder bore 154, the fracking fluid drawn therein becomes highly pressurized causing the opposite reaction of the suction and discharge valves 162, 164. Specifically, the suction valve 162 is forced against its respective valve seat 166 closing the suction chamber 152 while the discharge valve 164 is lifted from its valve seat 166 thereby opening the discharge chamber 156 allowing the pressurized fracking fluid to exit the pumping chamber 126. The pumping cycle can be repeated many times to continuously move fracking fluid through the pumping chamber 126.
To monitor, coordinate, and regulate operation of the various components the mobile fracking machine 100 including the pump 106, the mobile machine may be operatively associated with a computer control system adapted to process and execute various software instructions, programs, algorithms, functions, steps, routines, tasks, and processes. Referring to
To communicate with the other components of the computer system 200, the CPU 202 may be connected to a communications system 204, such as one or more communications busses, data links, communications networks, etc., designed to carry electronic signals between the components of the computer system 200. The communications system 204 can carry digital bits and/or bytes or analog signals and can operate in serial or parallel operating modes. The electronic signals may be multiplexed or combined to increase bandwidth along the communications system 204. The various components of the computer system 200 can be communicatively connected to the communications system 204 by ports, adapters, or the like.
For example, to rapidly send and store data to and from the CPU 202, the computer system can include a main memory 210 such as random access memory communicatively connected to the communications system 204 in close proximity to the CPU 202. The main memory 210 can be composed of multiple individual memory cells arranged in an addressable format that data can be written and read to. However, main memory 210 is typical volatile in nature and loses any stored data when power is cut. To store data more permanently, the computer system 200 can include non-volatile memory or secondary storage 212. Examples of secondary storage include hard drives, magnetic disks, optical disks, tapes, erasable programmable memory (EPROM), programmable read only memory (PROM) and other storage mediums. Accordingly, the secondary storage 212 may be permanently connected to the communications system 204 or removable from it.
To interface with an operator, the computer system 200 can include a monitor or operator display 220 such as a liquid crystal display (LCD) or technology connected to the communications system 204 through an appropriate driver 222. The communications system 204 can also connect with other input/output devices 224 to exchange information, including for example, keypads, touch screens, printers, etc. To interface with external devices, the communications system 204 can include communication ports 226, such as serial ports, parallel ports, USB ports, jacks, and the like which connect to remote devices via data cables, fiber optics and the like. In further embodiments, the communications system 204 may include transmitters/receivers 228 configured for wireless communications to send and receive data and information wirelessly. By way of example, the first and second pressure sensors 140, 142 may interface with the computer system through these communication ports 226 or transmitters/receivers 228.
Referring back to
The capacity of the computer system 200 to monitor and regulate discharge pressure from the pump may be restricted by the task management requirements of the CPU 202 arising from allocating CPU capacity among multiple operations and/or by the congestion of data traffic over the communications system 204. Therefore, in an embodiment, the computer system 200 can include a dedicated logic device 230 for monitoring and regulating pump pressure. The logic device 230 may be an integrated or discrete circuit or a plurality of integrated or discrete circuits including circuitry configured for conducting specific logical functions associated with the discharge pressure of the pump. Examples of suitable logic devices 230 include programmable logic devices such as field programmable gate arrays (FPGA), dedicated or customized logic devices such as application specific integrated circuits (ASIC) and gate arrays, or any other suitable type of circuitry or microchip. The logic device 230 can be configured to process digital or analog signals or can be configured as a mixed signal device. To receive data regarding pressures associated with the pump, the logic device 230 can be directly connected to the first and second pressure sensors 140, 142, although in other embodiments, the logic device 230 may also be communicatively connected to the communications system 204. In various embodiments, the logic device 230 can be a separate device from the other components of the computer system 200 or may be physically integrated with the other components of the computer system 200. The logic device may perform other operations or processes associated with the pump.
In an aspect of the disclosure, the logic device 230 can be configured to monitor the pressure data received from the first and/or second pressure sensors 140, 142 to assess the operating condition of the suction and discharge valves associated with the pump. Referring to
Referring to
If, however, the suction and/or discharge valves 162, 164 associated with one of the plurality of pumping chambers 126 were to operate uncharacteristically, for example, due to wear or deterioration of the suction and/or discharge valves 162, 164 or the associated valve seat 166, the irregular operation may be reflected in the discharge pressure curve 306. For example, uncharacteristic operation of the suction and/or discharge valves 162, 164 may be manifested as discharge pressure spikes 310 appearing in the discharge pressure from the pump 106. The discharge pressure spikes 310 can be significant, for example, increasing the discharge pressure curve 306 to approximately 60,000 kPa or decreasing it to approximately 30,000 kPa.
The discharge pressure spikes 310 may result from wear or deterioration affecting the timing of valve operation. For example, if the opening of the discharge valve 164 is delayed while the piston 160 extends into the cylinder bore 154 on a discharge stroke, the pressure of the fracking fluid in the cylinder bore 154 would be raised significantly over the steady state discharge pressure 308. Likewise, opening the discharge valve 164 too early could also cause significant discharge pressure spikes 310. Further, if the suction valve 162 operates incorrectly, insufficient fracking fluid may be drawn into the pumping chamber 126 or may be discharged back out of the pumping chamber 126 resulting in pressure spikes. The size or proportion of the discharge pressure spikes 310 may reflect the degree of wear or deterioration of the suction and/or discharge valves 162, 164. The frequency of the discharge pressure spikes 310 may indicate the number of suction and/or discharge valves 162, 164 that are deteriorating. For example, plot 300 may reflect the number of discharge pressure spikes 310 that occur if a single discharge and/or suction valve 162, 164 operates uncharacteristically. However, if multiple valves begin to operate uncharacteristically, the frequency of the discharge pressure spikes 310 will increase.
The present disclosure is applicable to monitoring operation of a pump 106 used, for example, during a fracking operation by, in part, monitoring the discharge pressure associated with the high-pressure fracking fluid discharged from the pump 106. Referring to
Referring collectively to
In a specific embodiment, the process 400 can determine the peak-to-peak amplitude associated with the discharge pressure curve 306. The process 400 can make this determination in a peak-to-peak determination step 406. Referring to plot 300, the peak-to-peak amplitude corresponds to the change from the highest value or peak to the lowest value or trough of the discharge pressure curve. Accordingly, a stable peak-to-peak amplitude 320 may correspond to the steady state discharge pressure 308 and is relatively small or nominal in value indicating normal or characteristic operation of the pump 106. However, if the maximum or high peak-to-peak amplitudes 322 assessed by the peak-to-peak determination step 406 and corresponding to the discharge pressure spikes 310 are relatively large, it may indicate uncharacteristic operation of the pump 106 and particularly of the suction and/or discharge valves 162, 164. The peak-to-peak amplitude of the discharge pressure curve 306 may be measured in real time based on the discharge pressure data as it is received or it can be assessed by another suitable conversion process such as, for example, averaging the individual pressure fluctuations in the discharge pressure curve 306.
In an embodiment, the data analysis step 404 and the peak-to-peak determination step 406 can be conducted in the logic device 230 included with the computer system 200. A possible advantage of utilizing a separate logic device 230 dedicated to pressure analysis is the logic device 230 can be customized to the high operating frequencies associated with the pump 106 and the plurality of individual pumping chambers 126. Further, by analyzing the high peak-to-peak amplitude 322 that corresponds to the discharge pressure spikes 310, rather than the frequencies of the peaks, the logic device 230 may be functional over a range of variable operating conditions associated with the pump 106. In an embodiment, the logic device 230 may isolate the discharge pressure spikes 310 from the steady state discharge pressure 308 by filtering or deducting the stable peak-to-peak amplitude 320 from the high peak-to-peak amplitude 322.
In a pressure spike detection step 408, the process 400 can detect if the discharge pressure spikes 310 are present in the discharge pressure curve 306. The process 400 can conduct the pressure spike detection step 408 as part of the peak-to-peak determination step 406 and can execute it in the logic device 230. The pressure spike detection step 408 detects the discharge pressure spikes 310 as emphasized or highlighted with respect to the steady state discharge pressure 308 associated with normal pump operation, which may correspond to comparing the high peak-to-peak amplitude 322 with the stable peak-to-peak amplitude 320. Hence, pressure spike detection step 408 can determine if the suction and/or discharge valves 162, 164 are operating uncharacteristically, indicating they may be worn or deteriorating.
In an embodiment, to compare or assess the wear or deterioration, the process 400 can, in a receive discharge pressure threshold step 410, receive a discharge pressure threshold and can compare, in a threshold comparison step 412, the discharge pressure threshold to the discharge pressure spikes 310 or the high peak-to-peak amplitude 322 as determined. If the discharge pressure threshold is exceeded, the process 400, in an alarm step 414, can issue an appropriate alarm, such as an audio or visual alarm, to indicate that preventative maintenance and service of the suction and/or discharge valves 162, 164 may be required. The computer system 200 can communicate the alarm to an operator or other person associated with the fracking operation. An advantage of utilizing the discharge pressure threshold is that it can be set to prevent activation of the alarm if wear or deterioration of the suction and/or discharge valves 162, 164 remains in acceptable limits. In other words, the discharge pressure threshold can be set above the stable peak-to-peak amplitude 320. The discharge pressure threshold may be empirically determined.
In another possible embodiment, the logic device 230 can be synchronized to the pump speed and/or crankshaft configuration so the logic device 230 may be capable of determining which pumping chamber 126 may be associated with the problematic suction and/or discharge valves 162, 164. For example, by understanding which pumping chamber 126 is conducting a discharge stroke and concurrently assessing the discharge pressure curve 306, the process 400 can advantageously identify the pumping chamber 126 associated with the discharge pressure spikes 310. In those embodiments utilizing the dedicated logic device 230 for pressure analysis, a further possible advantage is that the logic device 230 can be programmable such as a programmable logic device (PLD). Hence, the programmable logic device 230 can be configured in the field for the specific factors and variables regarding the fracking operation, for example, specific discharge pressure ranges and/or pumping speeds. This may be particularly advantageous where a plurality of fracking machines are employed in cooperation together during a fracking operation. As a further possible advantage, inclusion of the logic device 230 may release the other components of the computer system 200 to monitor and regulate the other operations of the fracking machine.
It will be appreciated that the foregoing description provides examples of the disclosed system and technique. However, it is contemplated that other implementations of the disclosure may differ in detail from the foregoing examples. All references to the disclosure or examples thereof are intended to reference the particular example being discussed at that point and are not intended to imply any limitation as to the scope of the disclosure more generally. All language of distinction and disparagement with respect to certain features is intended to indicate a lack of preference for those features, but not to exclude such from the scope of the disclosure entirely unless otherwise indicated.
Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context.
The use of the terms “a” and “an” and “the” and “at least one” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The use of the term “at least one” followed by a list of one or more items (for example, “at least one of A and B”) is to be construed to mean one item selected from the listed items (A or B) or any combination of two or more of the listed items (A and B), unless otherwise indicated herein or clearly contradicted by context.
Accordingly, this disclosure includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the disclosure unless otherwise indicated herein or otherwise clearly contradicted by context.
