Long-stroke pumping unit with counterweight flexible rod

Abstract

The invention relates to a long-stroke pumping unit with a counterweight flexible rod, which comprises a base, a motor is arranged on the base, a double-input-shaft gear box is arranged at the position of the base corresponding to a motor driving shaft, a brake is arranged at the position of the other input shaft of the double-input-shaft gear box, and the counterweight flexible rod is arranged on the base. A traction wheel set is arranged at the position, corresponding to the output end of the gearbox, of the base and comprises a pair of balance weight traction wheels arranged side by side, and a flexible polished rod traction wheel coaxially arranged is further arranged between the pair of balance weight traction wheels. A stand column is arranged on the base, a balance weight piece is arranged in the stand column, and the balance weight piece is connected with a balance weight traction wheel through a guide mechanism. A transmission guide wheel is arranged at the end, away from the stand column, of the base, a flexible polish rod is wound on the transmission guide wheel, one end of the flexible polish rod is fixed to the flexible polish rod traction wheel, and the other end of the flexible polish rod penetrates through a wellhead sealing device and then is connected with a plunger of a long-stroke oil well pump.

Description

Technical Field

[0001] This invention relates to the field of oil extraction equipment technology, and in particular to a long-stroke pumping unit with a counterweight flexible rod. Background Technology

[0002] The beam pumping units widely used in current oil extraction have significant technical limitations. Their maximum stroke is typically no more than 6 meters, while the stroke rate is usually maintained at 2 to 5 times per minute. This short-stroke, high-stroke operating mode causes the sucker rod string to be subjected to high-frequency alternating stress, exacerbating the hysteresis effect of the pump valve ball opening and closing, and significantly reducing pump efficiency. Simultaneously, the thousands of frictional movements between the rod and tubing daily cause severe uneven wear, drastically shortening the pump inspection cycle and increasing maintenance costs. In terms of energy consumption, due to the lack of an efficient load balancing mechanism, the motor must directly cope with the periodic peaks of the downhole load, forcing the equipment to be equipped with a drive system with excessively high power redundancy, resulting in energy waste due to "over-powered" operation and generally low system efficiency.

[0003] To overcome stroke limitations, some oilfields have adopted tower-type vertical pumping units. While these units can increase the stroke to 6-10 meters, they require the construction of taller support towers, resulting in high infrastructure costs and weak wind resistance. Furthermore, their counterweight system and load employ an asymmetrical motion trajectory, and the inertial impact generated during reversal creates destructive torque on the gearbox, significantly shortening the lifespan of critical components.

[0004] With the increasing urgency of developing unconventional oil and gas resources and tapping the potential of old oilfields, the industry urgently needs a new generation of pumping equipment to meet the following core requirements: to achieve a stroke of 15 meters or even 18 meters and above to increase the single pumping volume; to support ultra-low stroke operation of about 1 stroke per minute to extend rod and tube life; and to reduce system energy consumption through an efficient balancing mechanism. Summary of the Invention

[0005] The purpose of this invention is to overcome the defects in the prior art and provide a long-stroke oil pumping unit with a counterweight flexible rod.

[0006] To achieve the above objectives, the technical solution of the present invention is to design a long-stroke pumping unit with a counterweight flexible rod, including a base, a motor on the base, a dual-input shaft gearbox on the base corresponding to the drive shaft of the motor, one input shaft of the dual-input shaft gearbox being connected to the output shaft of the motor via a coupling, a brake on the other input shaft of the dual-input shaft gearbox, and a displacement monitor on the other input shaft of the dual-input shaft gearbox. The base corresponding to the output end of the gearbox is provided with a traction wheel set, the traction wheel set includes a pair of counterweight traction wheels arranged side by side, and a flexible smooth rod traction wheel arranged coaxially between the pair of counterweight traction wheels; The base is provided with a column, the middle of which is a rectangular cavity. A counterweight that can reciprocate is provided inside the cavity of the column. The counterweight is connected to the counterweight traction wheel through a guide mechanism. A transmission guide wheel is provided on the end of the base away from the column. A flexible guide rod is wound around the transmission guide wheel. One end of the flexible guide rod is fixed to the flexible guide rod traction wheel, and the other end passes through the wellhead sealing device and is connected to the plunger of the long stroke oil pump.

[0007] In a further preferred embodiment, the outer circumference of the flexible optical rod traction wheel is machined with a continuous spiral groove, the groove depth of which is greater than the diameter of the flexible optical rod, and the pitch of which is greater than the diameter of the flexible optical rod.

[0008] A further optimized technical solution is that the diameter of the flexible smooth rod traction wheel is larger than the diameter of the counterweight traction wheel.

[0009] In a further preferred embodiment, the guiding mechanism includes a pair of first guide wheels disposed at the top of the column and a pair of second guide wheels disposed on the side of the bottom of the column. Each of the first guide wheels and the second guide wheel directly below it is provided with a traction belt. One end of each traction belt is connected to one of the counterweight traction wheels, and the other ends of the two traction belts are simultaneously connected to the counterweight through a lock.

[0010] In a further preferred embodiment, a support rod is provided obliquely placed on the base between the column and the base.

[0011] In a further preferred embodiment, the number of support rods is two, one end of each support rod is hinged to the column and the other end is hinged to the base, and the column and the base are respectively provided with hinge seats, and the end of the support rod is connected to the hinge seat by bolts and nuts.

[0012] The advantages and beneficial effects of this invention are as follows: the output shaft of the motor-driven gearbox drives the traction wheel assembly to rotate; the flexible guide rod traction wheel extends and retracts the flexible guide rod to drive the plunger of the downhole oil pump; the synchronously running counterweight traction wheel controls the counterweight box to move in the opposite direction to balance the downhole load; the encoder monitors the stroke endpoint position in real time and controls its stroke; the normally closed hydraulic brake brakes in time in case of an accident to ensure the safety of the equipment; the frequency conversion control system supports stepless adjustment of the stroke rate within the required range.

[0013] Compared to traditional equipment, this invention: 1. Achieve long stroke: The stroke can reach more than 15 meters, which is 4 to 7 times that of conventional beam pumping units and 2 to 3 times that of tower pumping units.

[0014] 2. Achieve low stroke rate: The stroke rate can be infinitely adjusted even in the range of 0.1 to 1 strokes.

[0015] 3. Achieve high load capacity with low energy consumption: The counterweight and load are arranged symmetrically, which significantly reduces the requirements for the performance of hardware such as motors and brakes, thus reducing energy consumption; on the other hand, it leaves a greater margin for increasing the load at the wellhead.

[0016] 4. Reduce wear between the rods and tubes of the oil pump: Compared with conventional oil pumping units such as beam pumping units, the number of wear cycles between the rods and tubes is significantly reduced under the same output conditions. Attached Figure Description

[0017] Figure 1 The axial side of the present invention Figure 1 ; Figure 2 The axial side of the present invention Figure 2 ; Figure 3 The axial side of the present invention Figure 3 ; In the diagram: 1. Base; 2. Column; 3. Guide mechanism; 31. First guide wheel; 32. Traction belt; 33. Second guide wheel; 4. Counterweight traction wheel; 5. Flexible guide rod traction wheel; 6. Dual input shaft gearbox; 7. Support rod; 8. Motor; 9. Transmission guide wheel; 10. Flexible guide rod; 11. Plunger; 12. Counterweight. Detailed Implementation

[0018] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0019] like Figure 1-3 As shown, a long-stroke oil pumping unit with a counterweight flexible rod includes a base 1, on which a column 2 is provided. The column 2 is vertically arranged on the base 1, and the base 1 and the column 2 are detachable.

[0020] A motor 8 is mounted on the base 1, and the motor 8 is positioned near the outer side of the base 1. The drive shaft of the motor 8 is parallel to the column 2. A dual-input shaft gearbox 6 is located on the base 1 corresponding to the drive shaft of the motor 8. One input shaft of the dual-input shaft gearbox 6 is connected to the output shaft of the motor 8 via a coupling. A brake is located at the other input shaft of the dual-input shaft gearbox 6. The brake is a friction brake, which can be classified into disc brakes, externally gripping brakes, internally expanding shoe brakes, band brakes, combined band brakes, double-shoe brakes, multi-shoe brakes, simple band brakes, single-disc brakes, multi-disc brakes, fixed caliper brakes, floating brakes, etc.

[0021] A displacement monitor is also provided at the other input shaft position of the dual-input-shaft gearbox 6. Preferably, the displacement monitor is a displacement encoder. The displacement encoder converts linear or rotational displacement into processable digital / analog signals through sensors, including position feedback, speed monitoring and motion trajectory control.

[0022] The dual-input shaft gearbox 6 has an output end in a direction parallel to the drive shaft axis. The base corresponding to the output end is provided with a traction wheel set. The traction wheel set includes a pair of counterweight traction wheels 4 arranged side by side, and a flexible smooth rod traction wheel 5 arranged coaxially between the pair of counterweight traction wheels 4.

[0023] The traction wheel assembly includes flexible polished rod traction wheels 5 and counterweight traction wheels 4 with different diameters. The outer circumference of the flexible polished rod traction wheel 5 is machined with continuous spiral grooves, the groove depth of which is slightly greater than the diameter of the flexible polished rod 10, and the pitch is slightly greater than the rod diameter, ensuring that the flexible polished rod 10 can be tightly and orderly wound and arranged. The counterweight traction wheel 4 adopts a planar winding structure to support multiple layers of counterweight traction belts. The diameter of the flexible polished rod traction wheel 5 is larger than the diameter of the counterweight traction wheel 4. By amplifying the wellhead displacement through the diameter ratio, the displacement of the polished rod at the wellhead is greater than the displacement of the counterweight traction belt on the counterweight side for each rotation of the traction wheel, thereby reducing the height of the pumping unit.

[0024] The motor 8, brake, gearbox, and traction wheel assembly constitute a power and braking system. The motor 8 converts electrical energy into kinetic energy and drives the belt traction wheel to rotate reciprocally through the gearbox. The gearbox increases the torque to provide driving force for the pumping unit. At the same time, the brake uses frictional torque to reduce the speed of the drive shaft or stop its rotation, thereby decelerating, stopping, or keeping the moving parts (or moving machinery) in a stopped state, thus enabling the pumping unit to work and brake.

[0025] A transmission guide wheel 9 is provided on the end of the base 1 away from the column 2. A flexible guide rod 10 is wound around the transmission guide wheel 9. One end of the flexible guide rod 10 is fixed on the flexible guide rod traction wheel 5, and the other end passes through the wellhead sealing device and is connected to the plunger 11 of the long stroke oil pump.

[0026] The flexible polished rod 10 adopts a special composite polished rod structure, with a high-strength anti-torsion steel wire rope as the core, and a wear-resistant and corrosion-resistant polymer coated with a high-molecular adhesive layer. This composite structure results in a low coefficient of friction on the polished rod surface, and it possesses many characteristics such as resistance to high and low temperatures, oil resistance, wear resistance, smooth surface, and reliable wellhead sealing.

[0027] The column 2 is a frame structure with a rectangular cavity in the middle. A counterweight 12 that can reciprocate is provided in the cavity of the column 2. The counterweight 12 is connected to the counterweight traction wheel 4 through a guide mechanism 3. The guide mechanism 3 includes a pair of first guide wheels 31 provided at the top of the column 2 and a pair of second guide wheels 33 provided on the side of the bottom of the column 2. Each first guide wheel 31 and the second guide wheel 33 directly below it is provided with a traction belt 32. One end of each traction belt 32 is connected to one of the counterweight traction wheels 4, and the other ends of the two traction belts 32 are connected to the counterweight 12 through a lock.

[0028] A pair of pulleys are provided on the upper long side and the lower long side of the counterweight 12, respectively, and they roll in cooperation with the inner surface of the corresponding column 2. A pair of pulleys are also provided on the upper short side and the lower short side of the counterweight 12, which roll in cooperation with the inner surface of the corresponding column 2. This can prevent the counterweight 12 from rubbing against the column 2 and improve work efficiency.

[0029] The counterweight balancing system consists of a vertical column, a counterweight box, a high-strength counterweight traction belt, and a guide wheel assembly. The side wall of the counterweight box is equipped with guide pulleys that form a clearance fit with the guide rails on the inner wall of the column to ensure that the counterweight box moves along a vertical path. The guide wheel assembly includes bottom guide wheels and top guide wheels of the column. By adjusting the horizontal angle between each guide wheel, the risk of deviation when the counterweight traction belt is wound can be effectively eliminated.

[0030] A support rod 7 is also provided between the column 2 and the base 1, which is inclined on the base 1. In one embodiment, there are two support rods 7. The two ends of each support rod 7 are respectively hinged to the column 1 and the base 1. The column 2 and the base 1 are provided with hinge seats. The end of the support rod 7 is connected to the hinge seat by bolts and nuts. The support rod 7 can provide auxiliary support for the column 2, increase the rigidity of the column 2, and prevent the column 2 from tipping over.

[0031] In practical applications, the required counterweight box mass is first calculated based on the oil well operating conditions. The counterweight block combination inside the counterweight box is then adjusted. During installation, the transmission guide wheel 9 is positioned close to the wellhead side, and the counterweight column is set parallel to the rear of the pumping unit's power module. The distance between the two is determined based on the site space optimization. After the flexible polished rod 10 passes through the wellhead sealing device, one end is fixed to the starting groove of the flexible polished rod traction wheel 5. One end of the counterweight traction belt is connected to the top of the counterweight box, and after being turned by the first guide wheel 31 and the second guide wheel 33 of the column, it is fixed to the counterweight traction wheel 4.

[0032] After startup, motor 8 drives the traction wheel assembly via a gearbox reduction. When the flexible polished rod traction wheel rotates counterclockwise, it lifts the pump plunger. Simultaneously, the counterweight traction wheel rotates counterclockwise to release the traction belt, causing the counterweight box to descend. Gravitational potential energy is converted into auxiliary power for lifting the downhole load. Upon reaching the top dead center, the control system switches the motor direction, the flexible polished rod traction wheel releases the polished rod to lower the plunger, and the counterweight traction wheel retracts the counterweight traction belt to lift the counterweight box and store energy. The encoder in the displacement monitoring unit provides real-time feedback on the shaft end position, and the braking system can brake promptly in case of unexpected situations, ensuring equipment safety.

[0033] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A long-stroke pumping unit with a counterweight flexible rod, comprising a base, characterized in that, The base is equipped with a motor, and a dual-input shaft gearbox is provided at the position of the base corresponding to the motor drive shaft. One input shaft of the dual-input shaft gearbox is connected to the output shaft of the motor through a coupling. A brake is provided at the other input shaft position of the dual-input shaft gearbox, and a displacement monitor is also provided at the other input shaft position of the dual-input shaft gearbox. The base corresponding to the output end of the gearbox is provided with a traction wheel set, the traction wheel set includes a pair of counterweight traction wheels arranged side by side, and a flexible smooth rod traction wheel arranged coaxially between the pair of counterweight traction wheels; The base is provided with a column, the middle of which is a rectangular cavity. A counterweight that can reciprocate is provided inside the cavity of the column. The counterweight is connected to the counterweight traction wheel through a guide mechanism. A transmission guide wheel is provided on the end of the base away from the column. A flexible guide rod is wound around the transmission guide wheel. One end of the flexible guide rod is fixed to the flexible guide rod traction wheel, and the other end passes through the wellhead sealing device and is connected to the plunger of the long stroke oil pump.

2. The long-stroke pumping unit with counterweight flexible rod according to claim 1, characterized in that, The outer circumference of the flexible optical rod traction wheel is machined with continuous spiral grooves, the groove depth of which is greater than the diameter of the flexible optical rod, and the pitch of which is greater than the diameter of the flexible optical rod.

3. A long-stroke pumping unit with a counterweight flexible rod according to claim 1, characterized in that, The diameter of the flexible smooth rod traction wheel is larger than the diameter of the counterweight traction wheel.

4. A long-stroke pumping unit with a counterweight flexible rod according to claim 1, characterized in that, The guiding mechanism includes a pair of first guide wheels disposed on the top of the column and a pair of second guide wheels disposed on the side of the bottom of the column. Each first guide wheel and the second guide wheel directly below it are provided with a traction belt. One end of each traction belt is connected to one of the counterweight traction wheels, and the other ends of the two traction belts are connected to the counterweight through a lock.

5. A long-stroke pumping unit with a counterweight flexible rod according to claim 1, characterized in that, A support rod is also provided obliquely on the base between the column and the base.

6. A long-stroke pumping unit with a counterweight flexible rod according to claim 5, characterized in that, The number of support rods is two. One end of each support rod is hinged to the column and the other end is hinged to the base. The column and the base are respectively provided with hinge seats. The end of the support rod is connected to the hinge seat by bolts and nuts.

Images