PUMP SYSTEM USING VARIABLE CONTROL OF A TORQUE REQUIREMENT OF A FLUID PUMP

Description

TECHNICAL FIELD

The present disclosure relates generally to fluid pumps and, for example, to a pump system using variable control of a torque requirement of a fluid pump.

BACKGROUND

Large pumps are commonly used in oil and gas extraction applications. For example, a high-pressure reciprocating pump may be suitable for uses relating to hydraulic fracturing, well cementing, or well drilling. These large pumps may use poppet-style valves that open and close by differential pressure across the valves. The valves allow flow of a fluid into a fluid chamber to be compressed, and flow out from the fluid chamber when an internal pressure exceeds a working discharge pressure. A reciprocating pump may be driven by a prime mover, such as a reciprocating engine, a turbine engine, or an electric motor. Under startup conditions, or at other times when an available torque of the prime mover is relatively low, the prime mover may lack sufficient torque to operate the pump. In particular, the prime mover may struggle to start the pump against pressure due to the high discharge pressure, and thus high torque requirement, of the pump. Rather than stepping down the torque requirement of the pump, generally, the torque output of the prime mover is stepped up to meet the torque requirement through the use of additional or specialized equipment.

For example, an existing problem with using a reciprocating engine, such as a gas engine, to drive a high-pressure pump is that to start the pump against pressure, due to the high torque requirement, a transmission and a torque converter are needed. The transmission and the torque converter may add significant weight and bulk to a pump system. Moreover, the torque converter may generate significant heat that is handled by a cooler, which also adds weight and additional complexity to the pump system.

An existing problem with using a turbine engine to drive a high-pressure pump is that to start the pump against pressure, due to the high torque requirement, only a twin-shaft turbine engine with a 100% turndown ratio (where an output shaft of the turbine is at 0 revolutions per minute (rpm)) is able to handle the torque requirement. However, such a turbine engine is highly specialized, costly, and adds complexity to a pump system. Moreover, twin-shaft turbines generally are aeroderivative and not suitable for heavy-duty industrial applications. U.S. Pat. No. 11,643,915 (the '915 patent) discloses high pressure pumps and power generators that readily are installable on mobile fracturing transportation platforms, such as trailers, and that may include a dual fuel, dual shaft turbine engine mounted to the mobile fracturing trailer selectively to drive either the high pressure pumps or the power generators. The '915 patent states that the engine includes a power end that directly drives an engine output shaft, and that the engine output shaft is coupled to a reduction gearbox such that a speed of rotation of the engine output shaft is stepped down to a speed of rotation of a gearbox output shaft of the gearbox that is suitable for a hydraulic fracturing pump. The '915 patent further states that because the rotation speed of the engine output shaft is stepped down to the rotation speed of the gearbox output shaft, the torque of the engine output shaft is stepped up to the torque of the gearbox output shaft. Thus, the '915 patent does not step down the torque requirement of the hydraulic fracturing pump, but rather steps up the torque output of the turbine engine.

Likewise, an existing problem with using an electric motor to drive a high-pressure pump is that to start the pump against pressure, due to the high torque requirement, only a specialized and costly motor is able to handle the torque requirement. Moreover, the motor may be controlled using a variable frequency drive that adds significant weight, cost, and complexity to a pump system.

The pump systems of the present disclosure solve one or more of the problems set forth above and/or other problems in the art.

SUMMARY

A pump system may include a fluid pump including a fluid end. The fluid end may include a plunger configured for reciprocating movement, a suction valve biased to a closed position and configured to open during suction cycles of the fluid pump, and a discharge valve biased to a closed position and configured to open during discharge cycles of the fluid pump. The fluid pump may include a power end configured to drive reciprocating movement of the plunger. The pump system may be configured to variably control a torque requirement of the fluid pump. The pump system may include a reciprocating engine to produce torque to drive the power end of the fluid pump. The pump system may include a fixed-ratio gearbox or a dual-ratio gearbox operably coupling the power end of the fluid pump to the reciprocating engine using a non-fluid coupling.

A pump system may include a fluid pump including a fluid end. The fluid end may include a plunger configured for reciprocating movement, a suction valve biased to a closed position and configured to open during suction cycles of the fluid pump, and a discharge valve biased to a closed position and configured to open during discharge cycles of the fluid pump. The fluid pump may include a power end configured to drive reciprocating movement of the plunger. The pump system may be configured to variably control a torque requirement of the fluid pump. The pump system may include a turbine engine to produce torque to drive the power end of the fluid pump. The turbine engine may be a single-shaft turbine engine, or a twin-shaft turbine engine having a turndown ratio of less than 100%. The pump system may include a gearbox operably coupling the power end of the fluid pump to the turbine engine.

A pump system may include a fluid pump including a fluid end. The fluid end may include a plunger configured for reciprocating movement, a suction valve biased to a closed position and configured to open during suction cycles of the fluid pump, and a discharge valve biased to a closed position and configured to open during discharge cycles of the fluid pump. The fluid pump may include a power end configured to drive reciprocating movement of the plunger. The pump system may be configured to variably control a torque requirement of the fluid pump. The pump system may include an electric motor to produce torque to drive the power end of the fluid pump. The pump system may include an electrical system configured to operate the electric motor at only a constant speed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example hydraulic fracturing system.

FIGS. 2-3 are diagrams illustrating a sectional view of an example fluid pump system.

FIG. 4 is a diagram of an example pump system.

FIG. 5 illustrates plots showing operation of a reciprocating engine and a fluid pump without and with variable control of the torque requirement of the fluid pump.

FIG. 6 is a diagram of an example pump system.

FIG. 7 illustrates plots showing operation of a turbine engine and a fluid pump without and with variable control of the torque requirement of the fluid pump.

FIG. 8 is a diagram of an example pump system.

FIG. 9 illustrates plots showing operation of an electric motor and a fluid pump without and with variable control of the torque requirement of the fluid pump.

DETAILED DESCRIPTION

FIG. 1 is a diagram illustrating an example hydraulic fracturing system 100. For example, FIG. 1 depicts a plan view of an example hydraulic fracturing site along with equipment that is used during a hydraulic fracturing process. In some examples, less equipment, additional equipment, or alternative equipment to the example equipment depicted in FIG. 1 may be used to conduct the hydraulic fracturing process.

The hydraulic fracturing system 100 includes a well 102. Hydraulic fracturing is a well-stimulation technique that uses high-pressure injection of fracturing fluid into the well 102 and corresponding wellbore in order to hydraulically fracture a rock formation surrounding the wellbore. While the description provided herein describes hydraulic fracturing in the context of wellbore stimulation for oil and gas production, the description herein is also applicable to other uses of hydraulic fracturing.

High-pressure injection of the fracturing fluid may be achieved by one or more pump systems 104 that may be mounted (or housed) on one or more hydraulic fracturing trailers 106 (which also may be referred to as “hydraulic fracturing rigs”) of the hydraulic fracturing system 100. Each of the pump systems 104 includes at least one fluid pump 108 (referred to herein collectively, as “fluid pumps 108” and individually as “a fluid pump 108”). The fluid pumps 108 may be hydraulic fracturing pumps. The fluid pumps 108 may include various types of high-volume hydraulic fracturing pumps such as triplex or quintuplex pumps. Additionally, or alternatively, the fluid pumps 108 may include other types of reciprocating positive-displacement pumps or gear pumps. A type and/or a configuration of the fluid pumps 108 may vary depending on the fracture gradient of the rock formation that will be hydraulically fractured, the quantity of fluid pumps 108 used in the hydraulic fracturing system 100, the flow rate necessary to complete the hydraulic fracture, the pressure necessary to complete the hydraulic fracture, or the like. The hydraulic fracturing system 100 may include any number of trailers 106 having fluid pumps 108 thereon in order to pump hydraulic fracturing fluid at a predetermined rate and pressure.

In some examples, the fluid pumps 108 may be in fluid communication with a manifold 110 via various fluid conduits 112, such as flow lines, pipes, or other types of fluid conduits. The manifold 110 combines fracturing fluid received from the fluid pumps 108 prior to injecting the fracturing fluid into the well 102. The manifold 110 also distributes fracturing fluid to the fluid pumps 108 that the manifold 110 receives from a blender 114 of the hydraulic fracturing system 100. In some examples, the various fluids are transferred between the various components of the hydraulic fracturing system 100 via the fluid conduits 112. The fluid conduits 112 include low-pressure fluid conduits 112(1) and high-pressure fluid conduits 112(2). In some examples, the low-pressure fluid conduits 112(1) deliver fracturing fluid from the manifold 110 to the fluid pumps 108, and the high-pressure fluid conduits 112(2) transfer high-pressure fracturing fluid from the fluid pumps 108 to the manifold 110.

The manifold 110 also includes a fracturing head 116. The fracturing head 116 may be included on a same support structure as the manifold 110. The fracturing head 116 receives fracturing fluid from the manifold 110 and delivers the fracturing fluid to the well 102 (via a well head mounted on the well 102) during a hydraulic fracturing process. In some examples, the fracturing head 116 may be fluidly connected to multiple wells.

The blender 114 combines proppant received from a proppant storage unit 118 with fluid, which may be received from a hydration unit 120 of the hydraulic fracturing system 100. In some examples, the proppant storage unit 118 may include a dump truck, a truck with a trailer, one or more silos, or other types of containers. The hydration unit 120 receives water from one or more water tanks 122. In some examples, the hydraulic fracturing system 100 may receive water from water pits, water trucks, water lines, and/or any other suitable source of water. The hydration unit 120 may include one or more tanks, pumps, gates, or the like.

The hydration unit 120, or alternatively a chemical adding unit or the blender 114, may add fluid additives, such as polymers or other chemical additives, to the water. Such additives may increase the viscosity of the fracturing fluid prior to mixing the fluid with proppant in the blender 114. The additives may also modify a pH of the fracturing fluid to an appropriate level for injection into a targeted formation surrounding the wellbore. Additionally, or alternatively, the hydraulic fracturing system 100 may include one or more fluid additive storage units 124 that store fluid additives. The fluid additive storage unit 124 may be in fluid communication with the hydration unit 120 and/or the blender 114 to add fluid additives to the fracturing fluid.

In some examples, the hydraulic fracturing system 100 may include a balancing pump 126. The balancing pump 126 provides balancing of a differential pressure in an annulus of the well 102. The hydraulic fracturing system 100 may include a data monitoring system 128. The data monitoring system 128 may manage and/or monitor the hydraulic fracturing process performed by the hydraulic fracturing system 100 and the equipment used in the process. In some examples, the management and/or monitoring operations may be performed from multiple locations. The data monitoring system 128 may be supported on a van, a truck, or may be otherwise mobile. The data monitoring system 128 may include a display for displaying data for monitoring performance and/or optimizing operation of the hydraulic fracturing system 100. In some examples, the data gathered by the data monitoring system 128 may be sent off-board or off-site for monitoring performance and/or performing calculations relative to the hydraulic fracturing system 100.

The hydraulic fracturing system 100 includes a controller 130. The controller 130 may be a system-wide controller for the hydraulic fracturing system 100 or a pump-specific controller for a pump system 104. The controller 130 may be communicatively coupled (e.g., by a wired connection or a wireless connection) with one or more of the pump systems 104. The controller 130 may also be communicatively coupled with other equipment and/or systems of the hydraulic fracturing system 100.

As indicated above, FIG. 1 is provided as an example. Other examples may differ from what is described with regard to FIG. 1.

FIGS. 2-3 are diagrams illustrating a sectional view of an example fluid pump system 200. The fluid pump system 200 includes a fluid pump 201 (e.g., a fluid pump assembly) and a suction valve control system 240. The fluid pump 201 may be configured to operate in an application relating to oil and gas extraction, such as hydraulic fracturing, well cementing, and/or well drilling, among other examples. In some implementations, the fluid pump 201 may be mounted on a trailer to facilitate transportation of the fluid pump 201 between operational sites. The fluid pump 201 may be a positive displacement pump. For example, the fluid pump 201 may be a reciprocating pump, as shown.

In some implementations, the fluid pump 201 may have a capability to produce a maximum discharge pressure of at least 10,000 pounds per square inch (psi), at least 15,000 psi, or at least 20,000 psi. For example, the fluid pump 201 may be a hydraulic fracturing pump (e.g., the fluid pump 201 may correspond to the fluid pump 108). In some implementations, the fluid pump 201 may have a capability to produce a maximum discharge pressure of at most 7,500 psi, at most 5,000 psi, or at most 1,000 psi. For example, the fluid pump 201 may be a cement pump (e.g., configured to pump cement), a mud pump (e.g., configured to pump drilling fluid, also known as “drilling mud”), and/or an injection pump (e.g., configured to pump water and/or chemicals for injection to a well), among other examples.

The fluid pump 201 includes a fluid end 202 and a power end 204. The fluid end 202 may be connected to the power end 204 by stay rods 206. The fluid end 202 includes one or more fluid chambers 208 (only one shown). For example, the fluid pump 201 may include one, two, three, four, five, or more fluid chambers 208 and associated components. A fluid chamber 208 may sometimes be referred to as a “bore” of the fluid pump 201.

The fluid pump 201 may be configured to allow fluid to flow into the fluid chamber 208 during suction cycles of the fluid pump 201, and to discharge fluid during discharge cycles of the fluid pump 201. The fluid pump 201 includes a suction valve 214, disposed within a suction bore 210, that is configured to control fluid suction into the fluid chamber 208. The suction valve 214 (e.g., a poppet-style valve) may be biased (e.g., by a spring) to a closed position with respect to a suction valve seat 215 (thereby creating a seal) in the fluid chamber 208. For example, the suction valve 214 may be configured to close during discharge cycles of the fluid pump 201. Similarly, the fluid pump 201 includes a discharge valve 216, disposed within a discharge bore 212, that is configured to control fluid discharge from the fluid chamber 208. The discharge valve 216 (e.g., a poppet-style valve) may be biased (e.g., by a spring) to a closed position with respect to a discharge valve seat 217 (thereby creating a seal) in the fluid chamber 208. During a suction stroke of a plunger 220, fluid is allowed to flow from a suction manifold 218 through the suction valve 214 and into the fluid chamber 208. The fluid is then pumped in response to a discharge stroke (e.g., a forward stroke) of the plunger 220 and flows through the discharge valve 216 into the discharge bore 212. The discharge bore 212 may be fluidly coupled to a wellbore or other destination to supply high pressure fluid.

In operation, the reciprocating plunger 220 moves in a plunger bore 222 and is driven by the power end 204 of the fluid pump 201. The power end 204 may include a crankshaft 224 that is rotated by a gearbox output 226 (illustrated by a single gear, but may be more than one gear). A gearbox input 228 may be coupled to a transmission (not shown) and/or a prime mover 229 to rotate the gearbox input 228 during operation. In some implementations, the gearbox input 228 may be coupled directly to the prime mover 229 without use of a transmission. For example, the suction valve control system 240 described herein enables variable pump displacement, thereby allowing the power end 204 to be driven by the prime mover 229 without use of a transmission (although a transmission may be used in some configurations).

As one example, the prime mover 229 may include a reciprocating engine, which may be configured to drive the power end 204 without use of a transmission. As another example, the prime mover 229 may include a gas engine (also referred to as a “natural gas engine” or a “gaseous fuel engine”), which may be configured to operate at constant speed. As an additional example, the prime mover 229 may include a turbine engine, such as a single-shaft turbine engine or a dual-shaft turbine engine. In some implementations, the prime mover 229 may include an electric motor, such as a direct current (DC) electric motor or an alternating current (AC) electric motor. The electric motor may be configured to drive the power end 204 with or without control by a variable frequency drive (e.g., at constant speed). As a further example, the prime mover 229 may include a diesel engine, which may be configured to drive the power end 204 using a transmission.

A connecting rod 230 mechanically connects the crankshaft 224 to a crosshead 232 via a wrist pin 234. The crosshead 232 is mounted within a stationary crosshead housing 236, which constrains the crosshead 232 to linear reciprocating movement. A pony rod 238 connects to the crosshead 232 and has its opposite end connected to the plunger 220 to enable reciprocating movement of the plunger 220 (e.g., the plunger 220 is operably connected to the power end 204). The plunger 220 may be one of a plurality of plungers, such as, for example, three or five plungers, depending on the size of the fluid pump 201 (e.g., three cylinder, five cylinder, etc.) and the number of fluid chambers 208.

The plunger 220 extends through the plunger bore 222 so as to interface and otherwise extend within the fluid chamber 208. In operation, movement of the crankshaft 224 causes the plunger 220 to reciprocate within, or move linearly toward and away from, the fluid chamber 208. As the plunger 220 translates away from the fluid chamber 208 (a suction stroke of the plunger 220), the pressure of the fluid inside the fluid chamber 208 decreases, which creates a pressure differential across the suction valve 214. The pressure differential across the suction valve 214 enables actuation (e.g., opening) of the suction valve 214 to allow the fluid to enter the fluid chamber 208 from the suction manifold 218 (e.g., the fluid is pressurized to a low pressure, such as from 60 to 100 psi, by an outside system, such as a centrifugal pump, and pushed through the suction manifold 218). The pumped fluid is pushed into the fluid chamber 208 as the plunger 220 continues to translate away from the fluid chamber 208. As the plunger 220 changes directions and moves toward the fluid chamber 208 (a discharge stroke of the plunger 220), the fluid pressure inside the fluid chamber 208 increases, which creates a pressure differential across the discharge valve 216. Fluid pressure inside the fluid chamber 208 continues to increase as the plunger 220 approaches the fluid chamber 208 until the pressure differential across the discharge valve 216 is great enough to actuate (e.g., open) the discharge valve 216 and enable the fluid to exit the fluid chamber 208.

As an example, at top dead center (TDC) of the plunger 220 (when the plunger 220 is furthest from the crankshaft 224 center line, and volume in the fluid chamber 208 is at a minimum), pressure in the fluid chamber 208 is at, or is close to, a discharge pressure of the fluid pump 201. As the plunger 220 moves away from TDC, both the discharge valve 216 and the suction valve 214 may be closed, and pressure drops as volume in the fluid chamber 208 increases. The relationship between pressure and volume when the discharge valve 216 and the suction valve 214 are closed is defined largely by the compressibility of a fluid being pumped. When the pressure in the fluid chamber 208 is near, or is below, a suction pressure, the suction valve 214 opens, and flow begins to enter the fluid chamber 208 (e.g., while the plunger 220 is still moving away from TDC). The rate of flow into the fluid chamber 208 is controlled by the speed of the plunger 220. At about 80 degrees from TDC, when the crankshaft 224 is at 90 degrees to the centerline of the connecting rod 230, plunger velocity and suction flow rate is at a maximum. As the plunger 220 moves toward bottom dead center (BDC) of the plunger 220 (volume in the fluid chamber 208 is at a maximum), the plunger velocity and suction valve flow rate approaches zero. The suction valve 214 may close at this point, or slightly after when the plunger 220 begins to travel back towards TDC. As the plunger 220 moves toward TDC, both the suction valve 214 and the discharge valve 216 may be closed, and pressure increases in the fluid chamber 208 as volume is decreased. The discharge valve 216 opens when the pressure in the fluid chamber 208 is at, or slightly exceeds, the discharge pressure of the discharge bore 212. Flow may leave the fluid chamber 208 during the period when the discharge valve 216 opens and then closes, near or slightly after when the plunger 220 is back at TDC.

The suction valve control system 240 may include one or more valve control components 242 and a controller 244. A valve control component 242 is configured to control actuation of a suction valve 214, which may include controlling closing of the suction valve 214, controlling opening of the suction valve 214, and/or controlling lift (e.g., a maximum lift) of the suction valve 214. For example, the valve control component 242 is configured to restrict ordinary closing (e.g., ordinary closing due to a biasing member and/or pressurization of the fluid chamber 208) of the suction valve 214 in a controlled manner (e.g., the valve control component 242 may be configured to hold open the suction valve 214 and to release the suction valve 214 according to a desired timing). In one example, the valve control component 242 may include an actuator (e.g., a plunger-type actuator) that is hydraulically controlled (e.g., by a solenoid valve), or electronically and/or mechanically controlled. The actuator may be configured to actuate between a retracted position and an extended position, and, in some examples, to intermediate positions between the retracted position and the extended position. The actuator may be positioned such that in an extended position, the actuator can reach the underside of the suction valve 214 (e.g., the side of the suction valve 214 opposite the fluid chamber 208) when the suction valve 214 is in an open position. Alternatively, the actuator may be attached to the suction valve 214. In some examples, the valve control component 242 may include a physical part that is configured to directly contact a surface of the suction valve 214 in order to hold open the suction valve 214. The valve control component 242 is not limited to any particular type of actuator, physical part, and/or actuation mechanism described herein. The suction valve control system 240 may include a respective valve control component 242 for each suction valve 214 of the fluid pump 201. Phase between the valve control components 242 and the plunger 220 may be established from a timing wheel or a phase marker on the fluid pump 201, which can be correlated to control signals for the valve control components 242.

In FIG. 2, the valve control component 242 is shown not holding open the suction valve 214, and the suction valve 214 is in a closed position. In FIG. 3, the valve control component 242 is shown holding the suction valve 214 in an open position.

The controller 244 may include one or more memories and one or more processors communicatively coupled to the one or more memories. A processor may include a central processing unit, a graphics processing unit, a microprocessor, a controller, a microcontroller, a digital signal processor, a field-programmable gate array, an application-specific integrated circuit, and/or another type of processing component. The processor may be implemented in hardware, firmware, or a combination of hardware and software. The processor may be capable of being programmed to perform one or more operations or processes described elsewhere herein. A memory may include volatile and/or nonvolatile memory. For example, the memory may include random access memory (RAM), read only memory (ROM), a hard disk drive, and/or another type of memory (e.g., a flash memory, a magnetic memory, and/or an optical memory). The memory may be a non-transitory computer-readable medium. The memory may store information, one or more instructions, and/or software (e.g., one or more software applications) related to the operation of the controller 244.

The controller 244 may be mounted on the fluid pump 201, the fluid end 202, the suction manifold 218, another component of the fluid pump system 200, or the prime mover 229. Alternatively, the controller 244 may be remote from the fluid pump 201 or the prime mover 229. The controller 244 is communicatively coupled to the valve control components 242. The controller 244 may control a timing at which the valve control components 242 restrict closing of the suction valves 214 (e.g., the controller 244 may control a timing of actuation of the actuators controlling the suction valves 214). Operations described herein as being performed by the controller 244 may be performed by (e.g., split among) multiple controllers (e.g., a first controller may determine the timing and provide instructions to an additional controller that controls the valve control components 242).

The controller 244 may be communicatively coupled to one or more sensors on the fluid pump 201 (e.g., a pressure sensor or a flow rate sensor, among other examples) and/or communicatively coupled to one or more additional controllers associated with the fluid pump 201 and/or the prime mover 229. Thus, the controller 244 may receive input data from the sensor(s) and/or the additional controller(s), and the controller 244 may control a timing of the valve control components 242 (e.g., individually or in unison) in accordance with the input data. The input data may relate to various operating parameters relating to the fluid pump 201 and/or the prime mover 229.

For example, the input data may indicate a type of prime mover, a prime mover output speed, a prime mover available torque, a prime mover actual torque, a prime mover quick to neutral indication (e.g., an indication that the prime mover 229 should be immediately relieved of all output load), a transmission output speed, a transmission output torque, a transmission quick to neutral indication (e.g., an indication that the transmission should be immediately put in neutral), a pump crankshaft speed, a pump crankshaft angle, a pump plunger(s) location, a power end vibration, a fluid end vibration, a pump discharge pressure, a pump required input torque, a pump suction pressure, a pump lube oil pressure, a pump lube oil temperature, a fluid end valve leak detection indication, a fluid end packing leak detection indication, a desired pump flow indicated using an input device or determined automatically (e.g., using a machine learning model), a pump output torque, a pump flow, a quantity of pump plungers, a plunger size (e.g., a configured variable), a pump stroke (e.g., a configured variable), a pump rod load (e.g., calculated from plunger size and discharge pressure), and/or a pump displacement (e.g., calculated from pump stroke, plunger size, and quantity of plungers), among other examples. In some examples, the input data may include available torque of the prime mover and pump required input torque, and the suction valve control system 240 is configured to maintain (e.g., constantly, at least during a certain portion of operation such as start-up) pump required input torque at or below available torque of the prime mover 229. In some examples, the input data may include pump discharge pressure and pump flow, and the suction valve control system 240 is configured to determine pump required input torque based on pump discharge pressure and pump flow. In some examples, the input data may include pump discharge pressure and pump crankshaft speed, and the suction valve control system 240 is configured to determine pump required input torque based on pump discharge pressure and pump crankshaft speed. In some examples, the input data may include pump output torque and pump flow, and the suction valve control system 240 is configured to determine pump required input torque based on pump output torque and pump flow. In some examples, the input data may include pump output torque and pump crankshaft speed, and the suction valve control system 240 is configured to determine pump required input torque based on pump output torque and pump crankshaft speed. The exemplary input data described above, provided to the suction valve control system 240, can enable balancing of pump required input torque with available torque of the prime mover that solves one or more of the problems set forth herein and/or other problems in the art.

As indicated above, FIGS. 2-3 are provided as an example. Other examples may differ from what is described with regard to FIGS. 2-3.

FIG. 4 is a diagram of an example pump system 400. The pump system 400 may correspond to a pump system 104, described in connection with FIG. 1. As shown, the pump system 400 may include a prime mover 229 (which is a reciprocating engine in the pump system 400, and referred to as “reciprocating engine 229”), a gearbox 402, a mechanical coupling 404 (e.g., a driveline), and a fluid pump 201. The reciprocating engine 229, the gearbox 402, the mechanical coupling 404, and/or the fluid pump 201 may be mounted on a trailer 406. The trailer 406 may include a trailer bed on which equipment is mounted, and a set of wheels that support the trailer bed. The trailer 406 may have two axles (two pairs of wheels), three axles (three pairs of wheels), four axles (four pairs of wheels), or five axles (five pairs of wheels) depending on a weight of the equipment mounted on the trailer 406.

The reciprocating engine 229 may be a gas engine, a diesel engine (e.g., a dual fuel engine), a gasoline engine, or the like. For example, the reciprocating engine 229 may be a spark-ignited, gas engine. The reciprocating engine 229 may have a variable operating speed, or may have a constant operating speed. The reciprocating engine 229 is configured to produce torque to thereby drive the power end 204 of the fluid pump 201, which in turn drives the reciprocating movement of a plunger 220. For example, the reciprocating movement of the plunger 220 is achieved when the available torque of the reciprocating engine 229 overcomes a fluid pressure acting on the plunger 220.

The pump system 400 is configured to variably control a torque requirement of the fluid pump 201 (e.g., using a system that is part of, connected to, or separate from the fluid pump 201). For example, the pump system 400 may be capable of dynamically reducing (e.g., down to zero) and then increasing the torque requirement of the fluid pump 201. In some implementations, the pump system 400 may use the suction valve control system 240 to variably control the torque requirement of the fluid pump 201, as described herein. For example, variable control of the torque requirement may be provided by a valve control component 242, engaged with the fluid pump 201, and configured to control actuation of the suction valve 214. In particular, the valve control component 242 may be configured to maintain the suction valve 214 in an open position during a discharge cycle of the fluid pump 201, as described herein. In some examples, to maintain the suction valve 214 in an open position, the valve control component 242 may be actuated (e.g., by the controller 244) to an extended position such that the valve control component 242 holds open the suction valve 214 (e.g., by contacting, or pushing against, the underside of the suction valve 214, or based on attachment of the valve control component 242 to the suction valve 214). An open position of the suction valve 214 may correspond to an opening of the suction valve 214 during steady state suction cycles of the fluid pump 201. For example, an open position of the suction valve 214 may be a fully open position that corresponds to a maximum flow area of the suction valve 214.

Accordingly, the suction valve 214, that would otherwise close during discharge cycles of the fluid pump 201, is restricted from closing during the discharge cycles by the valve control component 242. As a result, a discharge stroke of the plunger 220 into the fluid chamber 208 will result in fluid being pumped through the open suction valve 214 back out into the suction manifold 218, rather than acting against the pressure of the closed discharge valve 216. In this way, the torque requirement of the fluid pump 201 is reduced. “Discharge cycle” may refer to a discharge stroke of the plunger 220, regardless of whether the discharge stroke discharges fluid from the fluid pump 201.

Through manipulation of a timing at which the suction valve 214 is maintained in an open position during a discharge cycle, the torque requirement of the fluid pump 201 can likewise be varied. For example, the suction valve 214 may be held open throughout a discharge cycle, or the suction valve 214 may be held open at a start of a discharge cycle and then released (e.g., closed) at a point during the discharge cycle (e.g., so that only partial flow occurs). By precise tuning of the timing, which can be modulated from cycle-to-cycle, continuously variable displacement, and thus continuously variable torque, of the fluid pump 201 may be achieved. Moreover, the timing at which the suction valves 214 of multiple fluid chambers 208 are maintained in open positions during discharge cycles can be coordinated to produce a desired torque requirement of the fluid pump 201. Holding the suction valve 214 open throughout a discharge cycle may also prevent an inadvertent creation of pressure.

Variably controlling the torque requirement of the fluid pump 201 allows the fluid pump 201 to be coupled to the reciprocating engine 229 without the use of a variable-ratio transmission (e.g., a multi-speed transmission) or a fluid coupling such as a torque converter. In this way, the added weight and complexity of the transmission and the torque converter (as well as a cooler for the torque converter) can be eliminated from the pump system 400, thereby enabling more flexible and less complex configurations for the trailer 406. In particular, the power end 204 of the fluid pump 201 may be operably coupled to the reciprocating engine 229 by the gearbox 402, which may be coupled to the fluid pump 201 using a non-fluid coupling such as the mechanical coupling 404. The gearbox 402 may be a fixed-ratio gearbox (e.g., that provides a constant gear ratio between input and output shafts of the gearbox 402). For example, the gearbox 402 may not provide stepping up of the torque output of the reciprocating engine 229, as the torque requirement of the fluid pump 201 can be stepped down in accordance with the available torque of the reciprocating engine 229. In some implementations, the gearbox 402 may be a dual-ratio gearbox (e.g., that provides no more than two gear ratios).

As indicated above, FIG. 4 is provided as an example. Other examples may differ from what is described with regard to FIG. 4.

FIG. 5 illustrates plots 500, 550 showing operation of a reciprocating engine and a fluid pump without and with, respectively, variable control of the torque requirement of the fluid pump. The plots 500, 550 show engine speed represented by a dark-shaded solid line, available engine torque represented by a light-shaded solid line, applied torque by the fluid pump represented by a small-dashed line, and pump flow rate represented by a large-dashed line.

Without variable control of the torque requirement of the fluid pump, as shown in plot 500, the available torque from the reciprocating engine is insufficient to start the fluid pump for a time period following a transmission shifting into gear. During this time period, a torque converter may provide multiplication of the torque output of the reciprocating engine, which is represented by the shaded region between the lines representing applied torque by the fluid pump and available engine torque. Pumping of the fluid pump may commence once the available torque from the reciprocating engine exceeds the applied torque by the fluid pump.

In contrast, with variable control of the torque requirement of the fluid pump, as shown in plot 550, the torque requirement of the fluid pump can be gradually increased (e.g., after the reciprocating engine reaches its rated speed and as engine speed increases) to coincide with the available torque from the reciprocating engine, thereby allowing the reciprocating engine to accelerate. For example, the torque requirement of the fluid pump can be variably controlled to maintain the torque requirement below the available torque of the reciprocating engine.

As indicated above, FIG. 5 is provided as an example. Other examples may differ from what is described with regard to FIG. 5.

FIG. 6 is a diagram of an example pump system 600. The pump system 600 may correspond to a pump system 104, described in connection with FIG. 1. As shown, the pump system 600 may include a prime mover 229 (which is a turbine engine in the pump system 600, and referred to as “turbine engine 229”), a gearbox 602, a mechanical coupling 604 (e.g., a driveline), and a fluid pump 201. The turbine engine 229, the gearbox 602, the mechanical coupling 604, and/or the fluid pump 201 may be mounted on a trailer 606, which may be similar to the trailer 406 described in connection with FIG. 4.

The pump system 600 is configured to variably control a torque requirement of the fluid pump 201 (e.g., using a system that is part of, connected to, or separate from the fluid pump 201), in a similar manner as described in connection with FIG. 4. Variably controlling the torque requirement of the fluid pump 201 allows the fluid pump 201 to be coupled to various non-specialized and lower-cost turbine engines (e.g., industrial, single-shaft turbine engines) without the need for a turndown ratio of 100% (a turndown ratio of 100% would otherwise be needed without variable control of the torque requirement). For example, the turbine engine 229 may be a single-shaft turbine engine. Alternatively, the turbine engine 229 may be a twin-shaft turbine engine having a turndown ratio of less than 100% (though unnecessary, the twin-shaft turbine engine may have a turndown ratio of 100% in some examples). For example, the turndown ratio may be less than or equal to 60%, less than or equal to 50%, less than or equal to 40%, less than or equal to 30%, or less than or equal to 20%. The turbine engine 229 is configured to produce torque to thereby drive the power end 204 of the fluid pump 201, which in turn drives the reciprocating movement of a plunger 220. For example, the reciprocating movement of the plunger 220 is achieved when the available torque of the turbine engine 229 overcomes a fluid pressure acting on the plunger 220.

The power end 204 of the fluid pump 201 may be operably coupled to the turbine engine 229 by the gearbox 602, which may be coupled to the fluid pump 201 using the mechanical coupling 604. The gearbox 602 may be suitable for use with the turbine engine 229. The gearbox 602 may be a fixed-ratio gearbox or a variable-ratio gearbox.

As indicated above, FIG. 6 is provided as an example. Other examples may differ from what is described with regard to FIG. 6.

FIG. 7 illustrates plots 700, 750 showing operation of a turbine engine and a fluid pump without and with, respectively, variable control of the torque requirement of the fluid pump. The plots 700, 750 show engine speed represented by a dark-shaded solid line, available engine torque represented by a light-shaded solid line, applied torque by the fluid pump represented by a small-dashed line, and pump flow rate represented by a large-dashed line.

Without variable control of the torque requirement of the fluid pump, as shown in plot 700, the available torque from the turbine engine is insufficient to start the fluid pump 201 for a time period following activation of an output shaft of the turbine engine 229. During this time period, which is represented by the shaded region between the lines representing applied torque by the fluid pump and available engine torque, the turbine engine may generate significant heat, which may reduce a useful life of the turbine engine. Pumping of the fluid pump may commence once the available torque from the turbine engine exceeds the applied torque by the fluid pump.

In contrast, with variable control of the torque requirement of the fluid pump, as shown in plot 750, the torque requirement of the fluid pump can be gradually increased (e.g., after the turbine engine reaches its rated speed) to coincide with the available torque from the turbine engine, thereby allowing the turbine engine to accept the load of the fluid pump gradually. For example, the torque requirement of the fluid pump can be variably controlled to maintain the torque requirement below the available torque of the turbine engine 229.

As indicated above, FIG. 7 is provided as an example. Other examples may differ from what is described with regard to FIG. 7.

FIG. 8 is a diagram of an example pump system 800. The pump system 800 may correspond to a pump system 104, described in connection with FIG. 1. As shown, the pump system 800 may include a prime mover 229 (which is an electric motor in the pump system 800, and referred to as “electric motor 229”), an electrical system 802, a mechanical coupling 804 (e.g., a driveline), and a fluid pump 201. The electric motor 229, the electrical system 802, the mechanical coupling 804, and/or the fluid pump 201 may be mounted on a trailer 806, which may be similar to the trailer 406 described in connection with FIG. 4. As shown, the pump system 800 may have a single-pump configuration, where the electric motor 229 drives a single fluid pump 201. Alternatively, the pump system 800 may have a twin-pump configuration, where the electric motor 229 drives two fluid pumps 201 positioned at opposite ends of the electric motor 229.

The pump system 800 is configured to variably control a torque requirement of the fluid pump 201 (e.g., using a system that is part of, connected to, or separate from the fluid pump 201), in a similar manner as described in connection with FIG. 4. Variably controlling the torque requirement of the fluid pump 201 allows the fluid pump 201 to be coupled to various non-specialized and low-cost electric motors that operate at a constant speed (variable speed operation of an electric motor would otherwise be used without variable control of the torque requirement). For example, the electric motor 229 may be a DC motor (e.g., with full torque capability at rated speed) or an AC motor (e.g., with full torque capability at zero speed) that operates at a constant speed. In some implementations, the electric motor 229 may be a variable speed motor (e.g., having a torque output that increases with speed).

Moreover, variably controlling the torque requirement of the fluid pump 201 allows operation of the electric motor 229 without the use of a variable frequency drive (VFD). In this way, the added weight and complexity of the VFD can be eliminated from the pump system 800, thereby enabling more flexible and less complex configurations for the trailer 806. The electric motor 229 is configured to produce torque to thereby drive the power end 204 of the fluid pump 201, which in turn drives the reciprocating movement of a plunger 220. For example, the reciprocating movement of the plunger 220 is achieved when the available torque of the electric motor 229 overcomes a fluid pressure acting on the plunger 220. The power end 204 of the fluid pump 201 may be operably coupled to the electric motor 229 by the mechanical coupling 804.

The electrical system 802 includes a power source for the electric motor 229 and/or a delivery system for delivering electrical power from the power source to the electric motor 229. The power source may include a battery, an electrical generator, a generator set, an electrical utility grid, an electrical microgrid, a solar power system, a wind power system, or the like. The delivery system may include one or more power cables, one or more converters (e.g., inverters, rectifiers, DC-DC converters, and/or AC-AC converters), one or more transformers, and/or one or more power electronics components (e.g., power distribution units). The electrical system 802 may be configured to operate the electric motor 229 at only a constant speed. For example, the electrical system 802 may lack any capability for variable-speed operation of the electric motor 229. As an example, the electrical system 802 may lack a VFD. In some implementations, the electrical system 802 may be configured to operate the electric motor 229 at a variable speed.

As indicated above, FIG. 8 is provided as an example. Other examples may differ from what is described with regard to FIG. 8.

FIG. 9 illustrates plots 900, 950 showing operation of an electric motor and a fluid pump without and with, respectively, variable control of the torque requirement of the fluid pump. The plots 900, 950 show motor speed represented by a dark-shaded solid line, available motor torque represented by a light-shaded solid line, applied torque by the fluid pump represented by a small-dashed line, and pump flow rate represented by a large-dashed line.

Without variable control of the torque requirement of the fluid pump, as shown in plot 900, the available torque from the electric motor is insufficient to start the fluid pump for a time period. Pumping of the fluid pump may commence once the available torque from the electric motor exceeds the applied torque by the fluid pump.

In contrast, with variable control of the torque requirement of the fluid pump 201, as shown in plot 950, the torque requirement of the fluid pump can be gradually increased, thereby allowing the electric motor to accept the load of the fluid pump gradually. For example, the torque requirement of the fluid pump can be variably controlled to maintain the torque requirement below the available torque of the electric motor. Plot 950 shows the torque requirement of the fluid pump increasing from zero after the electric motor reaches full speed and maximum available torque. However, the torque requirement of the fluid pump can be increased to coincide with the available torque from the electric motor increasing (similar to plots 550 and 750). Moreover, as shown in plot 950 by the shaded region below the line representing motor speed, the availability of the torque of the electric motor can be delayed to allow the electric motor to reach a minimum speed at which the electric motor can accept a load.

As indicated above, FIG. 9 is provided as an example. Other examples may differ from what is described with regard to FIG. 9.

INDUSTRIAL APPLICABILITY

The pump systems 400, 600, 800 described herein may be used with any positive displacement fluid pump, such as a reciprocating pump. For example, the pump systems 400, 600, 800 may be used with a pump that produces a high discharge pressure. In particular, the pump systems 400, 600, 800 may be employed in an application relating to oil and gas extraction, such as hydraulic fracturing, well cementing, and/or well drilling, among other examples. In such high-pressure uses, a fluid pump may have a high torque requirement, and a prime mover for the fluid pump may struggle to start the pump against pressure. Rather than stepping down the torque requirement of the pump, generally, the torque output of the prime mover is stepped up to meet the torque requirement through the use of additional or specialized equipment.

For example, in order for a gas engine to start a high-pressure pump against pressure, a transmission and a torque converter are needed to address the high torque requirement of the pump. However, the transmission and the torque converter may add significant weight and bulk to a pump system. Moreover, the torque converter may generate significant heat that is handled by a cooler, which also adds weight and additional complexity to the pump system. As another example, in the case of a turbine engine, a specialized and costly twin-shaft turbine engine with a 100% turndown ratio is needed to address the high torque requirement associated with starting a high-pressure pump against pressure. As a further example, in the case of an electric motor, a specialized and costly motor, controlled using a VFD, is needed to address the high torque requirement associated with starting a high-pressure pump against pressure. The VFD may add significant weight and complexity to a pump system.

The pump systems 400, 600, 800 described herein enable variable control of a torque requirement of a fluid pump. The pump's torque requirement can be controlled to maintain the torque requirement below the available torque of a prime mover. For example, the torque requirement can be increased gradually to coincide with the available torque from the prime mover, thereby allowing the prime mover to accept the load of the pump gradually. In this way, additional or specialized equipment, that otherwise would be used to address the high torque requirement associated with starting a high-pressure pump against pressure, can be eliminated from a pump system. In a hydraulic fracturing context, this allows for weight reduction as well as more flexible and less complex configurations for a hydraulic fracturing trailer.

For example, variable control of the torque requirement enables the pump system 400 to use a reciprocating engine as a prime mover without a transmission or a torque converter, thereby significantly reducing a weight and complexity of the pump system 400. As another example, variable control of the torque requirement enables the pump system 600 to use a low-complexity and lower-cost turbine engine (e.g., that is suitable for heavy-duty industrial applications), such as a single-shaft turbine engine or a twin-shaft turbine engine with a turndown ratio of less than 100%. As a further example, variable control of the torque requirement enables the pump system 800 to use a low-complexity and low-cost electric motor without the use of a VFD, thereby significantly reducing a weight and complexity of the pump system 800.

The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the implementations to the precise forms disclosed. Modifications and variations may be made in light of the above disclosure or may be acquired from practice of the implementations. Furthermore, any of the implementations described herein may be combined unless the foregoing disclosure expressly provides a reason that one or more implementations cannot be combined. Even though particular combinations of features are recited in the claims and/or disclosed in the specification, these combinations are not intended to limit the disclosure of various implementations. Although each dependent claim listed below may directly depend on only one claim, the disclosure of various implementations includes each dependent claim in combination with every other claim in the claim set.

As used herein, “a,” “an,” and a “set” are intended to include one or more items, and may be used interchangeably with “one or more.” Further, as used herein, the article “the” is intended to include one or more items referenced in connection with the article “the” and may be used interchangeably with “the one or more.” Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise. Also, as used herein, the term “or” is intended to be inclusive when used in a series and may be used interchangeably with “and/or,” unless explicitly stated otherwise (e.g., if used in combination with “either” or “only one of”).