Graded filtering sand control screen pipe

Abstract

A graded filtering sand control screen relates to the technical field of oil and gas production equipment and comprises an inner filter layer, an outer filter layer and elastic bodies, the middle of each elastic body is provided with an arched part arched inwards, a conical surface is arranged below each elastic body, the small end of each conical surface is fixedly connected with the inner filter layer, and the outer end of each conical surface is fixedly connected with the outer filter layer. The large head end of the conical surface is fixedly connected with the outer filter layer, an outer filter hole or an outer filter seam is formed in the outer filter layer between the conical surface and the elastic body above the conical surface, and an inner filter hole or an inner filter seam is formed in the inner filter layer between the elastic body and the conical surface above the elastic body; sand-containing crude oil at the well bottom sequentially passes through the outer filtering holes or the outer filtering seams, the filtering gaps and the inner filtering holes or the inner filtering seams and then enters the inner filtering layer, and sand filtered by the inner filtering holes or the inner filtering seams firstly falls into the filtering gaps, then is guided to the outer filtering holes or the outer filtering seams through the conical surfaces and finally slides out of the device. The failure of the sand control screen pipe caused by sand accumulation in the space between the filter layers is avoided.

Description

Technical Field

[0001] This utility model belongs to the technical field of oil and gas production equipment, and in particular relates to a graded filter sand prevention screen pipe. Background Technology

[0002] Sand production is a common occurrence in oil and gas fields due to geological and extraction factors. It becomes even more severe in the extraction of loose sandstone oil and gas reservoirs, heavy oil extraction, and after the oil field enters the high water-cut stage. Sand control has become a primary issue that must be considered in oil and gas field development. Sand control screens are an important tool for stabilizing production during oil and gas extraction, used to prevent larger sand and gravel particles from entering the production pipeline.

[0003] To improve the sand filtration effect of sand control screens, existing technologies use multi-stage filtration sand control screens. The defect of existing multi-stage filtration sand control screens is that the sand filtered by the middle layer filter falls between the middle layer filter and the outer layer filter, and the sand filtered by the inner layer filter falls between the inner layer filter and the middle layer filter. After a period of time, the space between the filter screens is filled with sand, and the sand control screen malfunctions. Utility Model Content

[0004] (I) Technical problems to be solved

[0005] The technical problem to be solved by this application is how to avoid sand accumulation in the space between filter layers.

[0006] (II) Technical Solution

[0007] A graded sand-control filter pipe includes an inner filter layer and an outer filter layer. The outer filter layer performs the first filtration, and the inner filter layer performs the third filtration. An annular space A is provided between the inner and outer filter layers. Segmented elastic bodies are disposed within the annular space A. Each elastic body has an inwardly arched portion in the middle. An annular filtration gap exists between the arched portion and the inner filter layer, serving as a second filtration. The elastic body can elastically contract or extend along its length. When the elastic body elastically extends, the filtration gap between the arched portion and the inner filter layer increases. This increased filtration gap allows sand stuck in the filtration gap to slide off. The lower end of the elastic body... The outer filter layer is fixedly connected, and the upper end of the elastomer slides with the outer filter layer, thus providing feasibility for the elastomer to elongate in the length direction. A conical surface is provided below each elastomer. The small end of the conical surface is fixedly connected to the inner filter layer, and the large end of the conical surface is fixedly connected to the outer filter layer. The conical surface can guide the sand filtered out by the second filtration to slide out. An outer filter hole or outer filter slot is opened on the outer filter layer between the conical surface and the elastomer above it. An inner filter hole or inner filter slot is opened on the inner filter layer between the elastomer and the conical surface above it. The sand-bearing crude oil at the bottom of the well enters the inner filter layer after passing through the outer filter hole or outer filter slot, the filter gap, and the inner filter hole or inner filter slot in sequence.

[0008] A further technical solution is as follows: In the inner filter layer, a liquid storage pipe is fixedly installed on the inner filter layer below each set of inner filter holes or inner filter slots. Adjacent liquid storage pipes are interlocked and there is an annular space B. During the upstroke of the pump, the crude oil at the bottom of the well enters the inner filter layer after passing through the outer filter holes or outer filter slots, the filter gap, and the inner filter holes or inner filter slots in sequence. During the downstroke of the pump, the crude oil in each liquid storage pipe loses its upward momentum and flows downward under the action of gravity, flowing down against the original upward path, thereby playing a certain role in unblocking.

[0009] A further technical solution is: a support ring is provided below each liquid storage tube, the liquid storage tube abuts against the support ring, and the support ring is fixedly connected to the inner filter layer.

[0010] A further technical solution is that a sliding sleeve is fixedly connected to the upper end of each elastomer, and the sliding sleeve slides in conjunction with the outer filter layer.

[0011] (III) Technical Effects

[0012] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0013] 1. This application achieves the goal of preventing sand accumulation in the space between filter layers by setting a conical surface and an elastomer between the inner filter layer and the outer filter layer, and opening an outer filter hole or outer filter slit on the outer filter layer between the conical surface and the elastomer above it, and opening an inner filter hole or inner filter slit on the inner filter layer between the elastomer and the conical surface above it.

[0014] 2. This application achieves this by fixing a liquid storage pipe on the inner filter layer below each group of inner filter holes or inner filter seams. During the upstroke of the pump, the crude oil at the bottom of the well passes through the outer filter hole or outer filter seam, the filter gap, and the inner filter hole or inner filter seam in sequence before entering the inner filter layer. During the downstroke of the pump, the crude oil in the lower end of the pump string and each liquid storage pipe loses its upward momentum and flows downward under the action of gravity, flowing down against the original upward path, thus playing a certain role in unblocking. During the unblocking process, due to the presence of the liquid storage pipe, the unblocking effect of each group of inner filter holes or inner filter seams is almost the same. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of this utility model.

[0016] The dashed arrows in the diagram indicate the path of the crude oil flowing upwards.

[0017] In the diagram: 1. External filter hole or external filter slit; 2. Conical surface; 3. Sliding sleeve; 4. External filter layer; 5. Arched part; 6. Elastomer; 7. Internal filter hole or internal filter slit; 8. Internal filter layer; 9. Liquid storage tube; 10. Support ring; 11. Annular space A; 12. Annular space B; 13. Filter gap. Detailed Implementation

[0018] To make the technical problems, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0019] This embodiment includes an inner filter layer 8 and an outer filter layer 4. The outer filter layer 4 has external filter holes or external filter slots 1, which serve as the first filtration. The inner filter layer 8 has internal filter holes or internal filter slots 7, which serve as the third filtration. An annular space A11 exists between the inner filter layer 8 and the outer filter layer 4. A segmented elastic body 6 is disposed within the annular space A11. Each segment of the elastic body 6 has an inwardly arched portion 5 in the middle. An annular filter gap 13 exists between the arched portion 5 and the inner filter layer 8, serving as the second filtration. The elastic body 6 can elastically contract or extend along its length direction (its own axial direction). When the filter gap 13 is blocked, the suction force of the oil pump forces the filter gap 13 to increase, i.e., forces the elastic body 6 to extend and deform. When the elastic body 6 elastically extends, the filter gap 13 between the arched portion 5 and the inner filter layer 8 increases, causing sand stuck in the filter gap 13 to slide off, thereby relieving the blockage of the filter gap 13. The lower end of the elastomer 6 is fixedly connected to the outer filter layer 4, and the upper end of the elastomer 6 is slidably engaged with the outer filter layer 4, thus providing feasibility for the elastomer 6 to elongate in the length direction. A conical surface 2 is provided below each elastomer 6. The small end of the conical surface 2 is fixedly connected to the inner filter layer 8, and the large end of the conical surface 2 is fixedly connected to the outer filter layer 4. The conical surface 2 can guide the sand filtered out in the second filtration to the outer filter hole or outer filter gap 1. The outer filter hole or outer filter gap 1 is opened on the outer filter layer 4 between the conical surface 2 and the elastomer 6 above it. The inner filter hole or inner filter gap 7 is opened on the inner filter layer 8 between the elastomer 6 and the conical surface 2 above it. The sand-laden crude oil at the bottom of the well passes sequentially through the outer filter hole or outer filter gap 1, the filter gap 13, and the inner filter layer 8. After passing through the filter hole or inner filter slot 7, the sand enters the inner filter layer 8. The sand filtered out by the outer filter hole or outer filter slot 1 automatically falls into the well. The sand filtered out by the filter gap 13 is guided through the conical surface 2 to the outer filter hole or outer filter slot 1, and then slides out of the outside of this application. The sand filtered out by the inner filter hole or inner filter slot 7 first falls into the filter gap 13, and then is guided through the conical surface 2 to the outer filter hole or outer filter slot 1, and then slides out of the outside of this application. There is no sand accumulation between the filter layers of this application, so the sand prevention screen will not fail due to sand accumulation in the space between the filter layers.

[0020] To achieve a certain unblocking effect on the sand control screen, a liquid storage pipe 9 is fixedly installed on the inner filter layer 8 below each group of inner filter holes or inner filter slots 7. Adjacent liquid storage pipes 9 are interlocked and have an annular space B12. During the upstroke of the pump, crude oil at the bottom of the well enters the inner filter layer 8 after passing through the outer filter hole or outer filter slot 1, the filter gap 13, and the inner filter hole or inner filter slot 7 in sequence, achieving three-stage filtration in this process. During the downstroke of the pump, the crude oil in each liquid storage pipe 9 loses its upward momentum and flows downward under the action of gravity, flowing against the original upward path. It flows backward when passing through each stage of filter holes, thus playing a certain unblocking role. The purpose of setting one liquid storage pipe 9 in each group of inner filter holes or inner filter slots 7 is to ensure that when the crude oil loses its upward momentum, the crude oil in each liquid storage pipe 9 flows downward evenly, so the unblocking effect of each group of inner filter holes or inner filter slots 7 is the same, with no significant difference.

[0021] A support ring 10 is provided below each liquid storage tube 9, and the liquid storage tube 9 rests against the support ring 10. The support ring 10 is fixedly connected to the inner filter layer 8 and is used to support the weight of the liquid storage tube 9.

[0022] Each elastomer 6 has a sliding sleeve 3 fixedly connected to its upper end. The sliding sleeve 3 is in sliding engagement with the outer filter layer 4. The presence of the sliding sleeve 3 prevents the upper end of the elastomer 6 from getting stuck with the outer filter layer 4.

Claims

1. A graded filtration sand control screen comprising an inner filtration layer (8) and an outer filtration layer (4), characterised in that: There is an annular space A (11) between the inner filter layer (8) and the outer filter layer (4), and a segmented elastic body (6) is arranged in the annular space A (11), the middle part of each elastic body (6) is provided with an inwardly arched arch (5), and the arch (5) and the inner filter layer (8) are provided with an annular filter gap (13), the elastic body (6) can be elastically contracted or elongated along the length direction of itself, the filter gap (13) between the arch (5) and the inner filter layer (8) is increased when the elastic body (6) is elastically elongated, the lower end of the elastic body (6) is fixedly connected with the outer filter layer (4), the upper end of the elastic body (6) is in sliding fit with the outer filter layer (4), a conical surface (2) is arranged below each elastic body (6), the small end of the conical surface (2) is fixedly connected with the inner filter layer (8), the large end of the conical surface (2) is fixedly connected with the outer filter layer (4), the outer filter layer (4) between the conical surface (2) and the elastic body (6) above the conical surface (2) is provided with an outer filter hole or an outer filter slot (1), and the inner filter layer (8) between the elastic body (6) and the conical surface (2) above the elastic body (6) is provided with an inner filter hole or an inner filter slot (7).

2. A graded filtration sand screen according to claim 1, characterized by: In the inner filter layer (8), a liquid storage pipe (9) is fixedly arranged below each group of inner filter holes or inner filter slots (7) in the inner filter layer (8), and the adjacent liquid storage pipes (9) are inserted and connected and there is an annular space B (12).

3. A graded filtration sand screen according to claim 2, characterized by: A supporting ring (10) is arranged below each liquid storage pipe (9), the liquid storage pipe (9) abuts against the supporting ring (10), and the supporting ring (10) is fixedly connected with the inner filter layer (8).

4. A graded filtration sand screen according to claim 1, characterized by: The upper end of each elastic body (6) is fixedly connected with a sliding sleeve (3), and the sliding sleeve (3) is in sliding fit with the outer filter layer (4).

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