PLANT FOR CONTROLLING DELIVERY OF PRESSURIZED FLUID IN A CONDUIT, AND A METHOD OF CONTROLLING A PRIME MOVER

Abstract

A plant for delivering a fluid in a conduit (10) comprises a prime mover (2), for example a gas turbine, which is configured to drive one or more fluid delivery systems (34a-c, 35a1-c1, 35a2-c2) for delivering a fluid in the conduit (10). A first sensor (16) is configured for sensing pressure variations in the pipe (10) and is connected to a first controller (7). The first controller (7) is configured to provide control signals to control valves (36a-c, 37a-c) for at least one fluid delivery system and to a control system (4, 3) for the prime mover (2). One or more hydraulic pumps (9a-c) are configured to operate the fluid delivery systems and are driven by the prime mover, whereby interaction between the hydraulic pumps and the prime mover is controlled based on sensed pressure in the pipe (10).

Claims

1. A method of controlling a plant for delivering a pressurized fluid in a conduit, the plant comprising: a prime mover configured to supply torque to one or more hydraulic pumps, each hydraulic pump being configured to supply hydraulic pressure to a respective positive displacement fluid delivery system via a respective control valve, each positive displacement fluid delivery system being configured to deliver the pressurized fluid in the conduit; a first sensor configured for sensing pressure variations in the conduit; and a first controller in data communication with the first sensor, the first controller being configured to provide control signals to the control valve for at least one of the fluid delivery systems and to a control system for the prime mover; the method comprising: sensing pressure variations in the pressurized fluid in the conduit; and based on the sensed pressure variations: (a) controlling at least one of the positive displacement fluid delivery systems; and (b) controlling power output of the prime mover.

2. The method of claim 1, further comprising determining an estimated power consumption.

3. The method of claim 2, wherein controlling power output of the prime mover comprises controlling a fuel supply of the prime mover.

4. The method of claim 3, further comprising controlling the at least one positive displacement fluid delivery system based on a set-point, the set-point being identified and set by an operator or an overall control system.

5. The method of claim 4, further comprising: the first controller providing control signals to the one or more hydraulic pumps; and controlling interaction between the hydraulic pumps and the prime mover based on sensed pressure variations in the conduit.

6. The method of claim 1, wherein the control valve for at least one of the fluid delivery systems is a plurality of control valves.

7. A plant for controlling delivery of a pressurized fluid in a conduit, the plant comprising: a prime mover configured to supply torque to one or more hydraulic pumps, each hydraulic pump being configured to supply hydraulic pressure to a respective positive displacement fluid delivery system via a respective control valve, each positive displacement fluid delivery system being configured to deliver the pressurized fluid in the conduit; a first sensor configured for sensing pressure variations in the conduit; and a first controller in data communication with the first sensor, the first controller being configured to provide control signals to the control valve for at least one of the fluid delivery systems and to a control system for the prime mover.

8. The plant of claim 7, wherein: the one or more hydraulic pumps are each configured to communicate with a hydraulic pump controller and a valve controller and to operate the fluid delivery systems; the one or more hydraulic pumps are each driven by the prime mover; and interaction between the one or more hydraulic pumps and the prime mover is controlled based on sensed pressure variations in the conduit.

9. The plant of claim 8, further comprising: valve outlet feedback pressure sensors connected to respective control valves; and a valve inlet pressure sensor connected to a respective control valve.

10. The plant of claim 9, wherein the first valve controller is configured for: receiving signals from the first sensor, the valve outlet feedback pressure sensors, and the valve inlet pressure sensor; receiving position feedback from the positive displacement fluid delivery systems; and providing the control signals to the control valves.

11. The plant of claim 10, wherein the prime mover is a gas turbine engine.

12. The plant of claim 11, further comprising a gear unit arranged between the gas turbine engine and the hydraulic pump.

13. The plant of claim 10, wherein the prime mover is a reciprocating engine.

14. The plant of claim 10, wherein at least one of the positive displacement fluid delivery systems comprises a positive displacement pump.

15. The plant of claim 10, further comprising at least one trailer; the prime mover, each hydraulic pump, and each positive displacement fluid delivery system being positioned on the at least one trailer.

16. The plant of claim 7, further comprising: valve outlet feedback pressure sensors connected to respective control valves; and a valve inlet pressure sensor connected to a respective control valve.

17. The plant of claim 7, further comprising: a respective valve outlet feedback pressure sensor connected to each control valve; and a valve inlet pressure sensor connected to a respective control valve.

18. The plant of claim 7, wherein the prime mover is selected from the group consisting of: a gas turbine engine, a reciprocating engine, and an electric motor.

19. The plant of claim 7, wherein at least one of the positive displacement fluid delivery systems comprises a positive displacement pump.

20. The plant of claim 7, further comprising at least one trailer; the prime mover, each hydraulic pump, and each positive displacement fluid delivery system being positioned on the at least one trailer.

21. The plant of claim 7, wherein the control valve for at least one of the fluid delivery systems is a plurality of control valves.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1 schematically illustrates one embodiment of a plant for controlling delivery of pressurized fluid in a conduit, in accordance with an embodiment of the current invention.

[0027] FIG. 2 is a perspective view of a mobile embodiment of the plant of FIG. 1, in a transportation configuration.

[0028] FIG. 3 is a perspective view of the mobile embodiment of FIG. 2, in a pumping (operational) configuration.

[0029] FIG. 4 is a perspective view of the mobile embodiment of FIG. 3, shown with the housing removed for illustration.

DETAILED DESCRIPTION OF AN EMBODIMENT

[0030] The following description may use terms such as horizontal, vertical, lateral, back and forth, up and down, upper, lower, inner, outer, forward, rear, etc. These terms generally refer to the views and orientations as shown in the drawings and that are associated with a normal use of the invention. The terms are used for the reader's convenience only and shall not be limiting.

[0031] Referring initially to FIGS. 2, 3, and 4, the invented plant is in this illustrated embodiment arranged as a mobile unit 18 on a trailer 19 and enclosed by a housing 20. Doors in the housing provide access to the plant, and rear doors may allow the movable unit comprising fluid end 21 with its double-acting cylinders 22 to be moved out and down (see FIG. 3) when the plant is in operation. Pipes 21a are configured for connection to well piping (not shown).

[0032] Referring to FIG. 4, the mobile plant in the illustrated embodiment includes a gas turbine 26 connected via a duct 27a to an air inlet 27, and also connected to an exhaust opening 26a. The gas turbine 26 receives fuel from a fuel tank 32. Supply lines and hoses, power lines and control lines, etc., are not shown, as these components are commonly known in the art.

[0033] The gas turbine 26 is connected to a set of single or tandem-mounted hydraulic pumps 30 via a gearbox 28. Reference numbers 31 and 29 denote a hydraulics tank and accumulator tanks, respectively. Louvers and air filtration container 23 is arranged towards the rear of the mobile unit, behind oil cooler gearbox 25 and hydraulics cooler 24.

[0034] The hydraulic pumps 30 operate hydraulic cylinders 22 in the plant's fluid ends 21. Each hydraulic cylinder operates one plunger, in each of the plant's two fluid ends 21.

[0035] A typical configuration of the invented plant will now be described with reference to the diagram in FIG. 1.

[0036] In FIG. 1, three systems are showndenoted A, B, C, respectively. It should be understood that only system C is illustrated in detail in FIG. 1, for clarity of illustration. The skilled person will understand that the components and functions illustrated and described with reference to system C also can be applied to systems A and B. It should also be understood that the invention shall not be limited to the number of systems shown in FIG. 1.

[0037] Reference number 1 denotes a power source having a prime mover 2. The prime mover 2 may be, for example, a gas turbine engine or a reciprocating engine, controlled via a throttle 3 (controlling fuel supply F and receiving information regarding rotation speed R). The prime mover 2 is connected, and configured to transfer torque T, to a gear unit 8. The gear unit 8 transfers torque T to individual hydraulic pumps 9a-c, and each pump has respective pump pressure sensors 13a-c.

[0038] If the prime mover 2 is a gas turbine, the gear unit 8 may be configured to reduce high-rpm output from the turbine. If the prime mover is of another type of engine (e.g. a reciprocating engine), the hydraulic pumps may be driven directly by the engine, and the gear unit 8 may be omitted.

[0039] Each hydraulic pump 9a-c supplies hydraulic pressure to respective positive displacement fluid delivery systems (in the illustrated embodiment, double-acting hydraulic cylinders 34a-c) via respective control valves 36a-c, 37a-c. A reservoir tank 11 and a cooler 17 are fluidly connected between the hydraulic pump 9c and the control valves 36c, 37c. The circuit also comprises an accumulator 33 for mitigating pressure pulses.

[0040] Each hydraulic cylinder 34a-c is operably connected to respective sets of fluid plungers 35a1-c1, 35a2-c2. The fluid plungers 35a1-c1, 35a2-c2 force fluid to the well via the fluid supply line 10. The invention shall, however, not be limited to such fluid plungers. Reference number 12 denotes a supply line from a fluid blending system.

[0041] Well feedback pressure sensor 16 is connected to, and configured to sense the pressure in (and hence pressure variations in) the supply line 10. Valve outlet feedback pressure sensors 15 are connected to respective control valves 36c, 37c. Valve inlet pressure sensor 14 is connected to control valve 36c. A valve controller 7 (typically a programmable logic controllerPLC) receives signals from the pressure sensors 14, 15, 16, position feedback Cp from the hydraulic cylinders, and provides control signals Vf to the control valves 36c, 37c.

[0042] A main control system 4 controls the throttle 3 based on power request Pr and provides power feedback Pf. The main control system 4 also receives transport security interlock feedback Ts from the gear unit 8, and estimated power consumption data EPC from the PLC 7, based on the sensed pressure variations by well feedback pressure sensor 16. A louver controller 5 is also in communication with the main control system 4, to open and close louvers (for e.g. ventilation and fire control). The main control system 4 receives data from a hydraulic pump controller 6 (e.g. a PLC) and provides a power command Ac to the hydraulic pump controller 6. The hydraulic pump controller 6 in turn provides the required displacement command Dc to the hydraulic pump 9c based on pump pressure feedback Pp (from the pressure sensor 13c). The main control system 4 also provides data regarding requested cylinder speed RCS to the valve controller 7, which in turn determines and provides the valve flow control signal Vf to the control valves 36c, 37c, as described above.

[0043] The plant thus includes a hydraulic-pressure/flow-controlled power transmission, in which all power from the prime mover is transformed into hydraulic power by the hydraulic pumps. The hydraulic pumps enable the prime mover to start against little or no load, and the hydraulic pumps may start the positive displacement fluid delivery system under varying load conditions.

[0044] When the plant is in use in a fracking operation, the prime mover 2 and the hydraulic pumps 9a-c operate the hydraulic cylinders 34a-c and fluid plungers 35a1-c1, 35a2-c2 to supply pressurized fracturing fluid to the line 10 (and thus the subterranean well). The hydraulic fracturing pressure generated in the well is a result of the well pressure and the hydraulic pressure generated by the plungers. The well pressure (which is sensed by the sensor 16) is communicated to the valve controller PLC 7, which controls the control valves 36a-c, 37a-c and also determines the estimated power consumption EPC, which is transmitted to the main control system 4. The prime mover fuel supply (e.g., turbine fuel injection) may thus be governed by the well pressure, or rather the variations in pressure, as sensed continuously by the sensor 16. The turbine fuel control receives pressure reading from the hydraulic control system, based on the pressure and rate reading from the hydraulic fracturing pressure. The hydraulic control system then performs a control action based on a set-point (rate/pressure) identified and set by the operator.

[0045] The delay which is inherent in hydraulic components, or which may be provided (controlled) by the main control system 4, provides sufficient time for the turbine fuel control to predict what is going to happen, and take action before it happens.

[0046] This means that the prime mover canbefore the requirement ariseseither increase the fuel injection (open throttle) to be ready for higher demand from the hydraulic pumps, or lower the fuel injection (restrict throttle) to adapt to the estimated future requirement of torque, and thereby accommodate the change in rate/pressure. This function may be particularly useful in embodiments where the prime mover is a gas turbine engine, as such turbines normally operate at high rotational speeds, and have low torque. The control system may in this fashion prevent the gas turbine engine from over-speeding, and further give the gas turbine engine a head-start on a predicted increase in torque demand.

[0047] When the requirement for fracturing fluid in the well changes, or actual consumption of fracturing fluid is changing and not complying with the set point as set by the operator or as determined by an overall control system, the valve controller 7 and pressure sensor 16 are sensing this, based on sensed pressure variations. The set point may also be defined based on a prioritized list, defined by an overall control system, of how deviating conditions are to be handled. Based on rate/pressure difference between the set point and the actual pressure reading (as sensed by 16), there will occur a situation that the actual power command Ac (fed to main controller 4 by the pump controller 6) differs from (less or more) the estimated power consumption EPC (fed to the main controller 4 by the valve controller 7). This will lead to a situation where the main controller 4 will be able to give appropriate control signals, and be able to control the instant in which the control signals are given, to both the pump controller 6 and to the prime mover throttle control 3whether simultaneously or at a controlled difference to have the prime mover act in a predictive manner.

[0048] Although an embodiment of the invention has been described with reference to three hydraulic pumps, it should be understood that other embodiments may utilize fewer or more hydraulic pumps.

[0049] Although an embodiment of the invention has been described with reference to a mobile unit, it should be understood that other embodiments may be formed as a stationary plant.

[0050] Although an embodiment of the invention has been described with reference to driving fluid ends (double-acting hydraulic cylinders), it should be understood that other embodiments may utilize other pumping principles driven by hydraulic flow and pressure, i.e. positive displacement pumps. The invention shall thus not be limited to the double-acting hydraulic cylinders.

[0051] Many different arrangements of the various components depicted, as well as components not shown, are possible without departing from the spirit and scope of the present disclosure. Embodiments of the present disclosure have been described with the intent to be illustrative rather than restrictive. Alternative embodiments will become apparent to those skilled in the art that do not depart from its scope. A skilled artisan may develop alternative means of implementing the aforementioned improvements without departing from the scope of the present disclosure. It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations and are contemplated within the scope of the claims. The specific configurations and contours set forth in the accompanying drawings are illustrative and not limiting.