Kinetic energy recovery system and method for power grid energy storage workover rig

Abstract

The invention relates to the field of petroleum drilling and repairing equipment, and discloses a kinetic energy recovery system and method for a grid electricity energy storage workover rig, and the kinetic energy recovery system comprises a battery cabinet, an electric control cabinet, a frequency conversion three-phase asynchronous motor or a permanent magnet synchronous motor, a reduction gearbox, a winch roller, a large rope, a traveling block hook and a tubular column; the winch drum adopts an integral ribbs rope groove; when the tubular column is lowered, gravitational potential energy of the tubular column is converted into kinetic energy, the winch drum is driven to rotate reversely, the variable-frequency three-phase asynchronous motor is driven to rotate reversely to generate three-phase alternating current, and the electric control cabinet converts the three-phase alternating current into direct current, stabilizes voltage and charges the direct current into a battery pack of the battery cabinet at constant current. The variable-frequency three-phase asynchronous motor serves as a power generation core, the battery cabinet serves as an energy storage core, the electric control cabinet serves as a control core, friction loss is reduced, battery management is enhanced, tubular column descending kinetic energy recycling and reusing are fully achieved, power consumption of an external network is reduced, braking consumption is reduced, and the energy-saving effect is quite remarkable.

Description

Technical Field

[0001] This invention relates to the field of oil drilling and workover equipment technology, specifically to a kinetic energy recovery system and method for a grid-connected energy storage workover rig. Background Technology

[0002] Workover rigs are specialized mechanical devices used for repairing downhole tubing or wellbore in oilfields, primarily for operations such as raising and lowering tubing and sucker rods. Existing workover rigs suffer from significant energy waste during operation: when lowering the tubing string, the enormous potential energy generated by the string's own weight is converted into heat energy and dissipated through braking, resulting not only in energy loss but also severe wear and tear on the braking system and high maintenance costs. Furthermore, traditional electric workover rigs rely on the well site power grid for power supply. Sudden power demands during tubing string lifting can easily impact the power grid, and in remote well sites with limited grid capacity, power shortages are common.

[0003] Currently, some advanced workover rigs are incorporating energy storage systems (such as supercapacitors or batteries) to recover braking energy. However, existing technologies still suffer from a single energy recovery mode: the feedback energy is typically consumed directly in the braking resistor, resulting in low energy utilization. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this invention provides a kinetic energy recovery system and method for grid-connected energy storage workover rigs, the technical solution of which is as follows: A kinetic energy recovery system for a grid-connected energy storage workover rig includes a battery cabinet, an electrical control cabinet, a variable frequency three-phase asynchronous motor or a permanent magnet synchronous motor, a gearbox, a winch drum, a main rope, a traveling block hook, and a tubing string. The battery cabinet, electrical control cabinet, variable frequency three-phase asynchronous motor, gearbox, and winch drum are mounted on the workover rig frame. The battery cabinet is electrically connected to the electrical control cabinet and the variable frequency three-phase asynchronous motor in sequence. The variable frequency three-phase asynchronous motor, gearbox, and winch drum are connected in sequence via a drive shaft. One end of the main rope is connected to the winch drum, and the other end passes over the top pulley of the derrick and is connected to the tubing string via the traveling block hook. The winch drum uses an integral Ribas rope groove, and employs a double-folded rope groove system where oblique and straight rope grooves alternate within the drum's circumferential rope grooves. The positions of the straight rope grooves between different circumferential rope grooves are exactly the same, and the positions of the oblique rope grooves between different circumferential rope grooves are exactly the same. The inclination angle of the oblique rope grooves relative to the straight rope grooves is between three and six degrees. When the pipe column is lowered, its gravitational potential energy is converted into kinetic energy, driving the winch drum to reverse and causing the variable frequency three-phase asynchronous motor to rotate in the opposite direction to generate three-phase AC power. The electrical control cabinet converts the three-phase AC power into DC power and stabilizes it before charging the battery pack in the battery cabinet with a constant current.

[0005] Furthermore, it also includes a torque sensor installed on the dead rope fastener of the workover rig. The torque sensor is electrically connected to the electrical control cabinet to collect the torque borne by the end of the main rope in real time.

[0006] Furthermore, the electrical control cabinet includes a PLC controller.

[0007] Furthermore, the electrical control cabinet includes a vector frequency converter, which includes an IGBT power module.

[0008] Furthermore, the electrical control cabinet includes a DC / DC converter.

[0009] Furthermore, the battery cabinet includes a BMS battery management module.

[0010] Furthermore, the battery cabinet includes a liquid cooling device.

[0011] A method for kinetic energy recovery of a grid-connected energy storage workover rig, the method relying on the aforementioned kinetic energy recovery system of a grid-connected energy storage workover rig, and including the following steps: (1) Standby preparation After the system starts up, the BMS battery management module automatically detects the battery pack voltage, temperature, and SOC state of charge, and the PLC controller establishes a communication connection with the vector inverter and the BMS battery management module. (2) Energy recovery The driller issues a command to lower the tubing string, which drives the winch drum to reverse under the weight of the tubing string. The reverse rotation of the winch drum drives the variable frequency three-phase asynchronous motor to rotate in the opposite direction through the connection between the drive shaft and the gearbox, and makes its rotor speed greater than the speed of the stator rotating magnetic field. The rotor moves in the magnetic field, cutting magnetic field lines, and enters the asynchronous generator mode through electromagnetic induction to generate three-phase alternating current, realizing the initial conversion and recovery of kinetic energy. (3) Energy storage When the BMS battery management module displays a SOC (State of Charge) of <80%, a feedback signal is sent to the PLC controller. The PLC controller then sends a command to the vector inverter. The vector inverter rectifies the AC power generated by the motor into DC power through the IGBT power module and sends it to the DC bus. After being regulated by the DC / DC converter, the DC power is charged into the battery pack at a constant current to ensure stable power transmission. When the BMS battery management module displays a SOC of ≥80%, a feedback signal is sent to the PLC controller. The controller automatically uses the remaining power to power other auxiliary equipment and consumes it through the braking resistor. (4) Energy feedback When the tube column is lifted, the DC power from the battery pack is inverted into AC power and then used in conjunction with the grid power to supply power, feeding the stored energy back to the power system.

[0012] Furthermore, in step (1), the battery pack uses a lithium iron phosphate battery pack with a rated capacity of 160-200 kWh. If the BMS battery management module displays a SOC state of charge of <80%, it sends a feedback signal to the PLC controller. The PLC controller controls the grid power to charge the battery pack through a DC / DC converter until the SOC state of charge is ≥80%. At the same time, the liquid cooling device is activated to control the battery temperature at 25-35°C, and the system enters standby mode.

[0013] Furthermore, in step (2), the voltage of the three-phase AC power generated by the variable frequency three-phase asynchronous motor is AC380~1000V.

[0014] The core principle of the kinetic energy recovery of this invention is a four-level conversion cycle of "potential energy-mechanical energy-electrical energy-chemical energy": (1) Potential energy release: When the column is lowered, the potential energy generated by its own gravity is converted into kinetic energy, which drives the winch drum to rotate and converts the potential energy into the mechanical energy of the winch drum; (2) Mechanical energy transmission: Through the transmission structure (reduction gearbox, transmission shaft) between the variable frequency three-phase asynchronous motor and the winch drum, the rotational mechanical energy of the winch drum is directly transmitted to the variable frequency three-phase asynchronous motor, which drives the motor rotor to rotate in the opposite direction; (3) Electrical energy conversion: When the motor rotates in the opposite direction, it enters the power generation mode and uses the principle of electromagnetic induction to convert mechanical energy into three-phase AC power; (4) Energy storage: Through the rectification of the vector frequency converter and the voltage regulation of the DC / DC converter, the AC power is converted into DC power and stored in the lithium iron phosphate battery pack in the form of chemical energy; (5) Recycling: When the column is lifted, the battery pack releases chemical energy, which is converted into AC power and then supplied in conjunction with the grid power to feed the stored energy back to the power system and complete the cycle.

[0015] Compared with the prior art, the present invention has the following main advantages: 1. This invention uses a variable frequency three-phase asynchronous motor as the power generation core, a battery cabinet as the energy storage core, and an electrical control cabinet as the control core. It has a compact structure and strong synergy. It converts the energy when the tube column is lowered into three-phase AC power, stores it in the form of DC power, and feeds it back to the power system. It fully realizes the recovery and reuse of kinetic energy, significantly reduces the power consumption of the external grid, reduces or even eliminates the frequency of use of braking resistors, and has significant energy saving and consumption reduction effects.

[0016] 2. This invention significantly slows down the aging rate of the battery under high-power charging and discharging conditions by accurately monitoring the battery status and providing intelligent protection, thereby extending the service life of core components and improving the economic efficiency throughout the entire life cycle.

[0017] 3. The winch drum adopts an integral Ribas rope groove, and uses a double-folded rope groove with alternating oblique and straight rope grooves within the circumferential rope groove of the drum. This solves the problems of rope tangling and biting during the winding process of traditional straight or spiral rope grooves, making the rope winding smooth and the load evenly distributed in each layer. It reduces sliding friction and wear between ropes and between the rope and the drum, extending the service life of the rope by more than 4 times. It also reduces non-effective energy consumption, and the transmission efficiency of the winch drum is improved by more than 3%, which is conducive to maximizing the recovery of kinetic energy during the lowering of the tube column.

[0018] 4. This invention meets the comprehensive requirements of well workover operations for high power, long endurance, high safety, zero emissions, and low noise, and is conducive to promoting the green and intelligent upgrading of well workover equipment. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structural layout of the present invention; Figure 2 A schematic diagram of the structural principle of a three-phase asynchronous motor generating electricity; Figure 3 A schematic diagram showing the semi-circular unfolding of the integral Ribas rope groove of the winch drum; Figure 4 This is a flowchart of the energy recovery and distribution control process of the present invention; In the diagram: 1-Battery cabinet, 2-Electrical control cabinet, 3-Variable frequency three-phase asynchronous motor, 4-Reduction gearbox, 5-Drive shaft, 6-Wind drum, 7-Main rope, 8-Torque sensor, 9-Traveling hook, 10-Tubing string, 11-Workover rig frame, 12-Dead rope retainer, 13-Heavy crane pulley, 14-Rotor, 15-Stator, 16-Stator rotating magnetic field, 17-Rotor rotation direction, 18-Stator magnetic field rotation direction, 19-Rope groove ridge, 20-Straight rope groove, 21-Inclined rope groove. Detailed Implementation

[0020] The present invention will be further described below with reference to the embodiments and accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of this application can be combined with each other. Example 1

[0021] See Figure 1 and Figure 3A kinetic energy recovery system for a grid-connected energy storage workover rig includes a battery cabinet 1, an electrical control cabinet 2, a variable frequency three-phase asynchronous motor 3 or a permanent magnet synchronous motor 4, a gearbox 4, a winch drum 6, a main rope 7, a traveling block hook 9, and a tubing string 10. The battery cabinet 1, electrical control cabinet 2, variable frequency three-phase asynchronous motor 3, gearbox 4, and winch drum 6 are mounted on the workover rig frame 11. The battery cabinet 1 is electrically connected to the electrical control cabinet 2 and the variable frequency three-phase asynchronous motor 3 in sequence. The variable frequency three-phase asynchronous motor 3, gearbox 4, and winch drum 6 are connected in sequence via a drive shaft 5. One end of the main rope 7 is connected to the winch drum 6, and the other end passes over the overhead pulley 13 at the top of the derrick and is connected via the traveling block hook 9. The pipe column 10 is connected to the winch drum 6, which adopts an integral Ribas rope groove and a double-folded rope groove with alternating inclined rope grooves 21 and straight rope grooves 20 in the circumferential rope groove of the drum. The straight rope grooves 20 between different circumferential rope grooves are in the same position, and the inclined rope grooves 21 between different circumferential rope grooves are in the same position. The inclination angle of the inclined rope grooves 21 relative to the straight rope grooves 20 is between three and six degrees. When the pipe column 10 is lowered, its gravitational potential energy is converted into kinetic energy, which drives the winch drum 6 to reverse and drives the variable frequency three-phase asynchronous motor 3 to rotate in the opposite direction to generate three-phase AC power. The electrical control cabinet 2 converts the three-phase AC power into DC power and stabilizes it, and then charges the battery pack of the battery cabinet 1 with a constant current. Example 2

[0022] See Figure 1 and Figure 3 A kinetic energy recovery system for a grid-connected energy storage workover rig, based on the technical solution described in Embodiment 1, further includes a torque sensor 8 installed on the dead rope fixing device 12 of the workover rig. The torque sensor 8 is electrically connected to the electrical control cabinet 2, collects the torque borne by the end of the main rope 7 in real time, and transmits the torque parameter signal to the electrical control cabinet 2. Example 3

[0023] See Figure 1 and Figure 3 A kinetic energy recovery system for a grid-connected energy storage well workover rig, based on the technical solution described in Embodiment 2, includes an electrical control cabinet 2 comprising a PLC controller, a vector frequency converter, and a DC / DC converter. The vector frequency converter includes an IGBT power module. The PLC controller serves as the control core of the entire system, connecting to all unit signals to achieve an adaptive collaborative control strategy based on real-time operating conditions and state awareness. The vector frequency converter can rectify the AC power generated by the variable frequency three-phase asynchronous motor 3 into DC power through the IGBT power module, and can detect signals such as the speed, voltage, and current of the variable frequency three-phase asynchronous motor 3. The DC / DC converter provides voltage regulation for the DC power. Example 4

[0024] See Figure 1 and Figure 3A kinetic energy recovery system for a grid-connected energy storage well workover rig, based on the technical solution described in Example 3, includes a battery cabinet 1 comprising a BMS (Battery Management System) module and a liquid cooling device. The liquid cooling device cools the BMS module, maintaining it at a suitable temperature. The BMS module integrates overvoltage, overcurrent, overtemperature, undervoltage, and short-circuit protection functions. It sets multi-level alarm thresholds for key parameters such as battery temperature, individual cell temperature difference, voltage, insulation resistance, charge / discharge current, and SOC (State of Charge), and implements a graded control mechanism of "Level 1 Reminder, Level 2 Warning, and Level 3 Shutdown," effectively ensuring battery safety and lifespan under various operating conditions and improving the overall economic efficiency throughout the battery's lifecycle. Example 5

[0025] See Figure 1 and Figure 3 A method for recovering kinetic energy from a grid-connected energy storage well workover rig includes the following steps: (1) Standby preparation After system startup, the BMS battery management module automatically detects the battery pack voltage, temperature, and SOC (State of Charge). The PLC controller establishes a communication connection with the vector inverter and the BMS battery management module. Battery cabinet 1 serves as the system's power compensation source and emergency power supply. Based on a comprehensive quantitative evaluation of its capacity, energy density, cycle life, and safety factor, lithium iron phosphate battery packs are used. The battery packs adopt a modular design with a rated capacity of 160–200 kWh, preferably 180 kWh, and a maximum continuous discharge current of 400 A to meet the power supply needs of the work unit. If the rated capacity of the battery pack is too small, the corresponding voltage and current will also be small, failing to meet production requirements; if the rated capacity of the battery pack is too large, the corresponding voltage and current will also be large, and the volume will also be large, making it difficult to arrange within the limited space of the workover rig chassis. If the BMS battery management module displays a SOC (State of Charge) of <80%, it sends a feedback signal to the PLC controller. The PLC controller then controls the grid power to charge the battery pack through a DC / DC converter until the SOC is ≥80%. At the same time, it activates the liquid cooling device to control the battery temperature between 25 and 35°C, and the system enters standby mode.

[0026] (2) Energy recovery The driller issues a command to lower the tubing string 10, which, under the gravity of the tubing string 10, drives the winch drum 6 to reverse. The reverse rotation of the winch drum 6, through the connection between the drive shaft 5 and the reduction gearbox 4, drives the variable frequency three-phase asynchronous motor 3 to rotate in the opposite direction, and makes the rotor 14 rotate faster than the stator rotating magnetic field 16. The rotor 14 moves in the magnetic field, cutting magnetic field lines, and enters the asynchronous generator mode through electromagnetic induction to generate three-phase alternating current, realizing the initial conversion and recovery of kinetic energy. The voltage of the three-phase alternating current generated by the variable frequency three-phase asynchronous motor 3 is AC380~1000V.

[0027] (3) Energy storage When the BMS battery management module displays a SOC (State of Charge) of <80%, a feedback signal is sent to the PLC controller. The PLC controller then sends a command to the vector inverter. The vector inverter rectifies the AC power generated by the motor into DC power through the IGBT power module and sends it to the DC bus. After being regulated by the DC / DC converter, the DC power is charged into the battery pack at a constant current to ensure stable power transmission. When the BMS battery management module displays a SOC of ≥80%, a feedback signal is sent to the PLC controller. The controller automatically uses the remaining power to power other auxiliary equipment and consumes it through the braking resistor.

[0028] (4) Energy feedback When column 10 is lifted, the DC power from the battery pack is inverted into AC power and then used in conjunction with the grid power to supply power, feeding the stored energy back to the power system.

Claims

1. A kinetic energy recovery system for a grid-connected energy storage well workover rig, characterized in that, The system includes a battery cabinet, electrical control cabinet, variable frequency three-phase asynchronous motor or permanent magnet synchronous motor, gearbox, winch drum, main rope, traveling block hook, and tubing string. The battery cabinet, electrical control cabinet, variable frequency three-phase asynchronous motor, gearbox, and winch drum are mounted on the workover rig frame. The battery cabinet is electrically connected to the electrical control cabinet and then to the variable frequency three-phase asynchronous motor in sequence. The variable frequency three-phase asynchronous motor, gearbox, and winch drum are connected in sequence via a drive shaft. One end of the main rope is connected to the winch drum, and the other end passes over the overhead crane pulley at the top of the derrick and connects to the tubing string via the traveling block hook. The winch drum uses a complete... The ribbed rope groove is a double-zigzag rope groove with alternating oblique and straight rope grooves within the circumferential rope groove of the drum. The straight rope grooves between different circumferential rope grooves are in the same position, and the oblique rope grooves between different circumferential rope grooves are in the same position. The inclination angle of the oblique rope grooves relative to the straight rope grooves is between three and six degrees. When the pipe column is lowered, its gravitational potential energy is converted into kinetic energy, driving the winch drum to reverse and driving the variable frequency three-phase asynchronous motor to rotate in the opposite direction to generate three-phase AC power. The electrical control cabinet converts the three-phase AC power into DC power and stabilizes it before charging the battery pack in the battery cabinet with a constant current.

2. The kinetic energy recovery system for a grid-connected energy storage well workover rig according to claim 1, characterized in that, It also includes a torque sensor installed on the dead rope fastener of the workover rig. The torque sensor is electrically connected to the electrical control cabinet and collects the torque borne by the end of the main rope in real time.

3. The kinetic energy recovery system for a grid-connected energy storage well workover rig according to claim 2, characterized in that, The electrical control cabinet includes a PLC controller.

4. The kinetic energy recovery system of a grid-connected energy storage well workover rig according to claim 3, characterized in that, The electrical control cabinet includes a vector frequency converter, which in turn includes an IGBT power module.

5. The kinetic energy recovery system of a grid-connected energy storage well workover rig according to claim 4, characterized in that, The electrical control cabinet includes a DC / DC converter.

6. The kinetic energy recovery system of a grid-connected energy storage well workover rig according to claim 5, characterized in that, The battery cabinet includes a BMS battery management module.

7. The kinetic energy recovery system of a grid-connected energy storage well workover rig according to claim 6, characterized in that, The battery cabinet includes a liquid cooling device.

8. A method for kinetic energy recovery in a grid-connected energy storage well workover rig, characterized in that, This kinetic energy recovery method relies on the kinetic energy recovery system of a grid-connected energy storage workover rig as described in claim 7, and includes the following steps: (1) Standby preparation After the system starts up, the BMS battery management module automatically detects the battery pack voltage, temperature, and SOC state of charge, and the PLC controller establishes a communication connection with the vector inverter and the BMS battery management module. (2) Energy recovery The driller issues a command to lower the tubing string, which drives the winch drum to reverse under the weight of the tubing string. The reverse rotation of the winch drum drives the variable frequency three-phase asynchronous motor to rotate in the opposite direction through the connection between the drive shaft and the gearbox, and makes its rotor speed greater than the speed of the stator rotating magnetic field. The rotor moves in the magnetic field, cutting magnetic field lines, and enters the asynchronous generator mode through electromagnetic induction to generate three-phase alternating current, realizing the initial conversion and recovery of kinetic energy. (3) Energy storage When the BMS battery management module displays a SOC (State of Charge) of <80%, a feedback signal is sent to the PLC controller. The PLC controller then sends a command to the vector inverter. The vector inverter rectifies the AC power generated by the motor into DC power through the IGBT power module and sends it to the DC bus. After being regulated by the DC / DC converter, the DC power is charged into the battery pack at a constant current to ensure stable power transmission. When the BMS battery management module displays a SOC of ≥80%, a feedback signal is sent to the PLC controller. The controller automatically uses the remaining power to power other auxiliary equipment and consumes it through the braking resistor. (4) Energy feedback When the tube column is lifted, the DC power from the battery pack is inverted into AC power and then used in conjunction with the grid power to supply power, feeding the stored energy back to the power system.

9. The method for kinetic energy recovery of a grid-connected energy storage well workover rig according to claim 8, characterized in that, In step (1), the battery pack uses a lithium iron phosphate battery pack with a rated capacity of 160-200 kWh. If the BMS battery management module displays a SOC state of charge of <80%, it sends a feedback signal to the PLC controller. The PLC controller controls the grid power to charge the battery pack through a DC / DC converter until the SOC state of charge is ≥80%. At the same time, the liquid cooling device is activated to control the battery temperature at 25-35°C, and the system enters standby mode.

10. The method for kinetic energy recovery of a grid-connected energy storage well workover rig according to claim 8, characterized in that, In step (2), the voltage of the three-phase AC power generated by the variable frequency three-phase asynchronous motor is AC380~1000V.

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