Sand tolerant oil well pump

Abstract

The utility model discloses a kind of sand-resistant oil well pump, relate to petroleum exploitation machinery field. Including pump barrel and plunger assembly, plunger assembly outer wall upper and lower ends are equipped with sealing ring. Lubricating oil injection hole is set up on the plunger wall between upper and lower sealing ring, its inside is equipped with filter screen. Plunger assembly inner chamber is equipped with scraping ring, scraping ring upper and lower sides are equipped with the baffle ring fixed in inner wall. When working, crude oil in plunger is filtered after filter screen and enters the gap between pump barrel and plunger assembly by lubricating oil injection hole, forms clean lubricating oil film, avoids dry friction and sand jam. In the up and down stroke of oil well pump, scraping ring reciprocating sliding between two baffle rings using inertia, automatically scrape off impurities on filter screen, prevent blockage. The utility model has ingenious structure, significantly prolongs the service life of oil well pump in sand-containing well.

Description

Technical Field

[0001] This utility model relates to the field of oil extraction machinery technology, specifically to a sand-resistant oil pump. Background Technology

[0002] In oilfield development, the extraction of sand-bearing wells has always been a technical challenge. When conventional oil pumps operate in sand-bearing crude oil, sand particles can easily enter the gap between the plunger and the pump barrel, causing severe wear on both the pump barrel and the plunger, and even "sand jamming" leading to sucker rod breakage. To prevent sand, some designs employ sealing structures with extremely small gaps, but this results in a lack of crude oil lubrication between the plunger and the pump barrel, creating "dry friction," which also rapidly shortens the service life of the oil pump.

[0003] Therefore, there is an urgent need for an oil pump that can prevent sand from getting stuck, ensure good lubrication, and have long-term anti-clogging function. Utility Model Content

[0004] The purpose of this invention is to provide a sand-resistant oil pump to solve the problems of sand jamming and dry friction in existing oil pumps in sandy wells.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A sand-resistant oil pump includes a pump barrel and a plunger assembly disposed inside the pump barrel. The outer wall of the plunger assembly is provided with upper and lower sealing rings. A through lubrication injection hole is opened on the side wall of the plunger assembly between the two sealing rings. A filter screen is provided on the inner side of the lubrication injection hole. The plunger assembly has a scraper ring that can slide axially in its inner cavity. The upper and lower sides of the scraper ring are respectively provided with retaining rings fixed on the inner wall of the plunger assembly. The outer wall of the scraper ring slides and fits against the inner surface of the filter screen.

[0006] Furthermore, the axial distance between the two retaining rings is greater than the axial height of the scraper ring, and the filter screen is located between the two retaining rings.

[0007] Furthermore, the filter screen is embedded in the inner wall of the plunger assembly, and the inner surface of the filter screen is flush with the inner wall of the plunger assembly.

[0008] Furthermore, the scraper ring is a hollow ring structure with an inner diameter not less than the inner diameter of the retaining ring, so as to allow crude oil to flow and avoid pressure drop.

[0009] Furthermore, an annular groove is formed on the outer wall of the plunger assembly, the sealing ring is installed in the annular groove, and the outer wall of the sealing ring slides and seals with the inner wall of the pump barrel.

[0010] Preferably, the sealing ring has a bowl-shaped cross-section, with the bowl-shaped opening facing outward towards the sand-containing side.

[0011] The beneficial effects of this utility model are: 1. Self-lubricating, anti-dry friction, and anti-sand jamming: After being filtered through a screen, the crude oil inside the plunger assembly enters the sealed annular gap formed by the two sealing rings, the pump barrel, and the plunger through the lubrication injection hole. The filtered clean crude oil forms a lubricating oil film here, which not only avoids dry friction between the plunger and the pump barrel, but also uses the sealing rings to isolate the sand-containing crude oil from the outside, completely solving the problem of "jamming when sand enters, and dry friction when sand does not enter".

[0012] 2. Self-cleaning and anti-clogging: Utilizing the reversing acceleration of the oil pump's up and down strokes. During the stroke alternation, the scraper ring slides relative to the upper and lower retaining rings due to inertia. Its outer wall automatically scrapes the filter screen surface, removing sand, colloids, and other impurities adhering to the filter screen. The impurities are carried away with the main fluid in the plunger, achieving real-time self-cleaning of the filter screen and ensuring long-term unobstructed lubrication. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 yes Figure 1 A magnified view of part A in the middle; Figure 3 yes Figure 1 A magnified view of part B in the middle; Figure 4 yes Figure 1 A magnified view of part C in the middle.

[0014] In the diagram: 1. Pump barrel; 2. Plunger assembly; 3. Sealing ring; 4. Lubrication injection hole; 5. Filter screen; 6. Scraper ring; 7. Retaining ring. Detailed Implementation

[0015] The present invention will be further described below with reference to specific embodiments.

[0016] The description of this utility model is merely a structural or even functional description of the embodiments, and the scope of this utility model is not limited by the embodiments described herein.

[0017] like Figures 1 to 4 As shown, this utility model provides a sand-resistant oil pump, including a pump barrel 1 and a hollow plunger assembly 2 coaxially disposed within the pump barrel 1. The outer wall of the plunger assembly 2 has two annular grooves, upper and lower, and sealing rings 3 (such as...) are respectively installed in the annular grooves. Figure 2 and Figure 4 As shown), the cross-section of the sealing ring 3 is bowl-shaped, with the bowl-shaped opening facing outward towards the sand-containing side. The outer wall of the sealing ring 3 slides and seals with the inner wall of the pump barrel 1, thereby forming an annular lubrication cavity between the two sealing rings 3 and between the outer wall of the plunger assembly 2 and the inner wall of the pump barrel 1.

[0018] like Figure 3 As shown, a lubrication injection hole 4 penetrating the plunger wall is provided on the side wall of the plunger assembly 2 between the two sealing rings 3. A filter screen 5 is embedded in the inner side of the lubrication injection hole 4 (i.e., the side closest to the inner cavity of the plunger assembly 2). The inner surface of the filter screen 5 is flush with the inner wall of the plunger assembly 2 and does not obstruct the flow of fluid inside the plunger.

[0019] Inside the plunger assembly 2, corresponding to the position of the filter screen 5, a hollow annular scraper ring 6 is provided. The outer diameter of the scraper ring 6 matches the inner diameter of the plunger assembly 2, allowing its outer wall to slide against the inner surface of the filter screen 5. On the upper and lower sides of the scraper ring 6, retaining rings 7 are respectively fixed to the inner wall of the plunger assembly 2. The axial distance between the two retaining rings 7 is greater than the axial height of the scraper ring 6, providing the scraper ring 6 with a range of vertical sliding stroke.

[0020] Working principle of this utility model: When the pump is operating, sand-laden crude oil from the well enters the hollow cavity of the plunger assembly 2 and flows upward. Due to the high pressure of the crude oil downhole, some of the crude oil in the cavity of the plunger assembly 2 passes through the filter screen 5, removing impurities such as sand particles, becoming clean crude oil. This clean crude oil then enters the annular lubrication cavity between the two sealing rings 3 directly through the lubrication injection hole 4. The air originally in the lubrication cavity is compressed and expelled, or dissolved in the oil. When the pump reaches the predetermined working depth, the lubrication cavity is completely filled with crude oil from the well. This clean crude oil forms a lubricating film between the plunger assembly 2 and the pump barrel 1, ensuring the pump is always in a good wet lubrication state and avoiding dry friction. At the same time, the upper and lower sealing rings 3 effectively prevent external sand-laden crude oil from entering the friction pair, preventing sand jamming.

[0021] During the reciprocating stroke of the plunger assembly 2 driven by the pumping unit, when the stroke direction changes (i.e., the plunger accelerates upwards or downwards), the scraper ring 6, due to its own inertia, overcomes friction and slides axially relative to the plunger assembly 2 within the range defined by the two retaining rings 7. During this sliding process, the outer wall of the scraper ring 6 scrapes the surface of the filter screen 5, removing sand, paraffin, and other impurities adhering to or clogging it. These removed impurities are directly mixed into the upward-flowing mainstream crude oil within the plunger assembly 2 and pumped to the surface. Thus, the pump's own mechanical motion achieves automatic, maintenance-free cleaning of the filter screen 5.

[0022] Of course, the above description is only a preferred embodiment of this utility model and should not be considered as limiting the scope of the embodiments of this utility model. This utility model is not limited to the above examples, and all equivalent changes and improvements made by those skilled in the art within the scope of this utility model should be included in the patent coverage of this utility model.

Claims

1. A sand-resistant oil pump, comprising a pump barrel (1) and a plunger assembly (2) disposed within the pump barrel (1), characterized in that: The outer wall of the plunger assembly (2) is provided with two sealing rings (3) at the top and bottom; a through lubrication injection hole (4) is provided on the side wall of the plunger assembly (2) between the two sealing rings (3), and a filter screen (5) is provided on the inner side of the lubrication injection hole (4). The inner cavity of the plunger assembly (2) is provided with a scraper ring (6) that can slide along the axial direction. The upper and lower sides of the scraper ring (6) are respectively provided with retaining rings (7) fixed on the inner wall of the plunger assembly (2). The outer wall of the scraper ring (6) slides and fits against the inner surface of the filter screen (5).

2. The sand-resistant oil pump according to claim 1, characterized in that: The axial distance between the two retaining rings (7) is greater than the axial height of the scraper ring (6), and the filter screen (5) is located between the two retaining rings (7).

3. The sand-resistant oil pump according to claim 1, characterized in that: The filter (5) is embedded in the inner wall of the plunger assembly (2), and the inner surface of the filter (5) is flush with the inner wall of the plunger assembly (2).

4. The sand-resistant oil pump according to claim 1, characterized in that: The scraper ring (6) has a hollow ring structure. Its inner diameter is not less than the inner diameter of the retaining ring (7).

5. A sand-resistant oil pump according to claim 1, characterized in that: The outer wall of the plunger assembly (2) is provided with an annular groove, the sealing ring (3) is installed in the annular groove, and the outer wall of the sealing ring (3) slides and seals with the inner wall of the pump barrel (1).

6. A sand-resistant oil pump according to claim 1, characterized in that: The sealing ring (3) has a bowl-shaped cross section with the bowl-shaped opening facing the sand-containing side.

Images