Oil pumping polished rod falling buffer sinking device

Abstract

The present application relates to the energy industry, more particularly to the protection of pumping beam in oil exploitation, using the principle of static friction, a protection device is provided for pumping beam, which can buffer and prevent the pumping beam from falling into the oil well when it suddenly breaks. The structure of the present application is: using the super large static friction provided by polyurethane rubber, the present application is tightly bound on the pumping beam below the hanger and above the beam sealing box through high-strength screws. In order to facilitate installation without disassembling the pumping beam, the clamping seat for installing the screw is divided into two half rings, combined with the upper and lower two pieces which are also divided into two halves, and connected into a whole clamping seat through the plug screw. The inner side of the clamping seat has an arc-shaped pressing plate for compressing polyurethane rubber, and the lower layer of the combined plate has a buffer compression spring below. The present application is easy to install, which can effectively buffer and prevent the pumping beam from falling into the well when it suddenly breaks.

Description

Technical Field

[0001] This invention relates to the energy industry, and more specifically to the protection of sucker rods in oil extraction. Background Technology

[0002] The polished rod at the wellhead is a key component connecting the surface pumping unit and the downhole sucker rod string. It withstands friction and wear under alternating loads. The conventional material is high-quality carbon steel of grade 50-55 or alloy steel of 35CrMo or 30CrMo. The lower end of the polished rod passes through the polished rod seal (packing box) and connects to the downhole sucker rod string, which is thousands of meters long and weighs several tons. The upper end passes through the hanger and is held firmly by the sharp claws of the polished rod square clamp and connected to the pumping unit. When the pumping unit is working, during its upward stroke, the hanger is driven by a steel cable, which in turn drives the polished rod upward. During its downward stroke, the polished rod, together with the downhole sucker rod string connected below, moves downward under its own weight. The polished rod moves up and down repeatedly, lifting the crude oil from the bottom of the well to the surface, completing the cyclic pumping operation.

[0003] In existing technologies, polished rod clamps are used to hold the polished rod in place during production operations to prevent it from falling into the oil well. However, the sharp teeth of the clamps cause plastic deformation on the surface of the polished rod when it is clamped, resulting in mechanical damage that is irreparable. The cyclic alternating stress generated when the polished rod moves up and down under load causes stress concentration at the mechanically damaged areas, often leading to cracks and fractures starting from the damaged areas. When the polished rod breaks, oil well production stops, and when it falls into the well, a large amount of crude oil spills from the wellhead, causing environmental pollution. In addition, it is time-consuming and laborious to retrieve the polished rod. Summary of the Invention

[0004] This invention relates to the energy industry, and more specifically to the protection of sucker rods in oil extraction. It provides a protective device for sucker rods to cushion and prevent them from falling into the oil well in the event of sudden breakage.

[0005] The solution of this invention is achieved through the following technical means: When the sucker rod 9 suddenly breaks, the sucker rods connected to it, which are over a thousand meters long downhole and weigh several tons (the uppermost one protruding above the surface is the sucker rod, and all others downhole are sucker rods), will be pulled into the well by their own weight. To solve this problem, the invention utilizes the high static friction provided by the rubber core 2 and is secured to the lower part of the upper part of the sucker rod 9 by a high-strength fastening screw 8. This allows for convenient fastening without disassembling the sucker rod. In this invention, the mounting bracket 4 with the tightening screw 8 is divided into two semi-rings. These are combined with the upper and lower combination plates 5 and 1, which are also divided into two halves, and connected into a single mounting bracket 4 by the plug screw 6. The inner side of the mounting bracket 4 has an arc-shaped pressure plate 3 for compressing the rubber core 2, and a buffer spring 7 is located below the lower combination plate 1. In this way, even if the sucker rod 9 suddenly breaks, this invention can effectively buffer and prevent it from getting stuck above the sucker rod sealing box at the wellhead, and it will not fall into the well, thus keeping the wellhead sealed.

[0006] Figure 1 This is a longitudinal full-section front view. Figure 2 This is a sectional view along axis A-A. Figure 3 This is a top view (view from direction M). Figure 4 This is an N-direction view (bottom view).

[0007] Figure 1 , Figure 2 , Figure 3 , Figure 4 Detailed list of parts: 1. Lower assembly plate, 2. Rubber core, 3. Arc-shaped pressure plate, 4. Card holder, 5. Lower assembly plate, 6. Plug screw, 7. Buffer spring, 8. Tightening screw, 9. Oil sucker rod, 10. Hanger, 11. Square clip for the oil sucker rod, L1. Diameter cut of the upper and lower assembly plates; L2. Diameter cut of the card holder.

[0008] Among them, parts 9, 10, and 11 are not of this invention. The polished rod sealing box (not shown in the figure) is arranged below the polished rod and is used to seal the wellhead when the polished rod passes through during oil production.

[0009] The positive effects of this invention are: when the sucker rod suddenly breaks, it effectively buffers and prevents it from getting stuck above the sucker rod sealing box at the wellhead and falling into the well, keeping the wellhead sealed and preventing crude oil spills and environmental pollution. There is no need to retrieve the sucker rod, simplifying the aftermath and enabling oil production to be restored as soon as possible.

[0010] Detailed Implementation: To prevent the sucker rod 9 from accelerating downwards under a pulling force of several tons when it suddenly breaks, this invention designs a rubber core 2 surrounding the sucker rod 9, with an arc-shaped pressure plate 3 and a retainer 4 arranged from the center outwards. The retainer 4 has an upper combination plate 5 and a lower combination plate 1 on its upper and lower sides. As a preferred example, the rubber core 2 is made of highly tear-resistant polyurethane rubber, which can provide sufficiently large static friction. For ease of installation, it is made into a ring and cut along an axial direction. The arc-shaped pressure plate 3, which provides clamping force to the rubber core 2, is composed of four nearly 90° fan-shaped rings with a groove in the middle, which facilitates the installation of the rubber core 2 and makes the rubber core 2 more conducive to withstanding axial and radial forces. Eight tightening screws 8, which tighten the arc-shaped pressure plate 3, are evenly distributed and assembled on the card seat 4. The card seat 4 is a ring with a Spike boss on the upper and lower sides, and is cut into two identical half rings along the diameter. The two half ring card seats 4 are connected and assembled into a complete card seat 4 by the upper combination plate 5 and the lower combination plate 1, which are positioned by the Spike boss groove, through four evenly distributed upper and lower plug screws 6. The lower combination plate 1 and the upper combination plate 5 are both cut into two halves along the diameter, and their diameter cut L1 is perpendicular to the diameter cut L2 of the card seat 4. Four buffer springs 7 are arranged at the lower end of the lower combination plate 1 to buffer the dynamic load impact generated when the sucker rod 9 falls rapidly, so as to better protect the sucker rod sealing box below.

[0011] To ensure that the present invention is adaptable to working conditions, its strength must be verified in three aspects: 1. Verification of the compressive and shear strength of the rubber core 2 when it provides the maximum static friction force; 2. Determination of the number of tightening screws 8 and verification of their compressive strength; 3. Verification of the shear strength of the plug screws 6.

[0012] This invention fully considers the dynamic load generated by the downhole sucker rod's own weight and its free fall when the sucker rod suddenly breaks. The core material 2 is optimally selected as polyurethane rubber with a safety factor of 3.0; the tightening screw 8 is grade 8.8 with a safety factor of 2.0; and the plug screw 6 is grade 12.9 with a safety factor of 2.0. All three of the above items have passed the strength check and meet the corresponding specifications.

Claims

1. A sucker rod drop buffer and anti-sinking device, characterized in that: Its structure consists of a rubber core (2) surrounding the oil sucker rod (9), with an arc-shaped pressure plate (3) and a card seat (4) arranged from the center outwards. The card seat (4) has an upper combination plate (5) and a lower combination plate (1) on the top and bottom.

2. The sucker rod drop buffer and anti-sinking device according to claim 1, characterized in that: As a preferred example, the core (2) is made of polyurethane rubber with high tear resistance, formed into a ring and cut along one axial direction.

3. A sucker rod drop buffer and anti-sinking device according to claims 1 and 2, characterized in that: The arc-shaped pressure plate (3) that provides clamping force to the rubber core (2) is composed of four nearly 90° fan-shaped rings with a groove in the middle, which facilitates the installation of the rubber core (2) and makes the rubber core (2) more conducive to bearing axial and radial forces.

4. A sucker rod drop buffer and anti-sinking device according to claims 1 and 3, characterized in that: Eight clamping screws (8) for pressing the arc-shaped pressure plate (3) are evenly distributed and assembled on the card holder (4). The card holder (4) is a ring with a Spike boss on the upper and lower sides, and is cut into two identical half rings along the diameter.

5. A sucker rod drop buffer and anti-sinking device according to claims 1 and 4, characterized in that: Two semi-ring brackets (4) are connected and assembled into a complete bracket (4) by the upper assembly plate (5) and the lower assembly plate (1) positioned by the groove of the Speck platform through four evenly distributed screws (6) on the upper and lower sides.

6. A sucker rod drop buffer and anti-sinking device according to claims 1 and 5, characterized in that: Both the lower assembly plate (1) and the upper assembly plate (5) are cut into two halves along the diameter, and the diameter cut L1 is perpendicular to the diameter cut L2 of the card seat (4).

7. A sucker rod drop buffer and anti-sinking device according to claims 1 and 5, characterized in that: Four buffer springs (7) are arranged at the lower end of the lower assembly plate (1).

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