An inner cone type sand control screen

Abstract

The present invention relates to an inner cone type sand control screen. It mainly solves the problem that existing sand control screens cannot filter out the silt components in fracturing sand, which causes sand jam in the oil well pump. It is characterized in that a plurality of ceramic filter core assemblies (4) are provided inside the outer tube (3) of the screen. The inner cone type sand control screen can filter out the silt components in the fracturing sand before entering the pump barrel of the oil well pump, thereby ensuring normal production after the oil well is fracturing.

Description

Technical Field

[0001] The invention relates to the field of sand control after oilfield fracturing, in particular to an inner cone type sand control screen pipe. Background Art

[0002] Oil well fracturing is a key measure for increasing oilfield production. After fracturing a well is commissioned or resumed, sand flow typically occurs. Fracturing sand flows from the formation into the wellbore along with the oil. To prevent fracturing sand from entering the wellbore pump and causing sand jams, which could affect the pump's lift, a sand-control screen is typically installed below the pump to filter out the fracturing sand. This ensures the pump remains unaffected by the fracturing sand and maintains normal, stable operation.

[0003] However, as oilfield development deepens, large-scale fracturing is often used to develop tight oil, resulting in a significant increase in the amount of fracturing sand injected. At the same time, severe sand return often occurs after fracturing wells are put into production. Fracturing sand flows back into the wellbore from the formation. Although existing sand control screens can filter out most of the fracturing sand, they cannot filter out the silt component in it, resulting in... Summary of the Invention

[0004] In order to overcome the deficiency of existing sand control screens that cannot filter out the silt components in fracturing sand, thus causing sand jam in the oil well pump, the present invention provides an inner cone type sand control screen, which can filter out the silt in the fracturing sand before entering the pump barrel of the oil well pump, thereby ensuring normal production after the oil well is fracturing.

[0005] The technical solution of the present invention is: an inner cone type sand control screen pipe, comprising a screen pipe upper joint and a screen pipe lower joint, a screen pipe outer tube connected between the screen pipe upper joint and the screen pipe lower joint, and a plurality of ceramic filter element assemblies are arranged inside the screen pipe outer tube.

[0006] The ceramic filter element assembly comprises a filter element outer shell and a filter element inner shell, with a ceramic filter element arranged therebetween; the filter element outer shell is provided with a filter element outer shell liquid inlet slit, and the filter element inner shell is provided with a filter element inner shell liquid outlet slit.

[0007] The liquid inlet slit of the filter element outer shell is located above the liquid outlet slit of the filter element inner shell.

[0008] The filter element inner shell is conical, the liquid outlet gap of the filter element inner shell is located at the large diameter end of the filter element inner shell, and the liquid inlet gap of the filter element outer shell corresponds to the small diameter end of the filter element inner shell.

[0009] The two ends of the filter element outer shell and the filter element inner shell are connected to the housing upper cover and the housing lower cover respectively.

[0010] The present invention has the following beneficial effects: due to the adoption of the above-mentioned scheme, the combination of the liquid inlet gap of the filter element shell, the ceramic filter element, and the liquid outlet gap of the filter element inner shell can filter out the fracturing sand carried in the oil and the very small amount of silt components contained therein; the oil adopts a top-in and bottom-out design, the oil enters from the liquid inlet gap of the filter element shell, passes through the ceramic filter element, and then enters the internal conical channel of the ceramic filter element assembly from the liquid outlet gap of the filter element inner shell. The height of the ceramic filter element is fully utilized, which increases the length of the fracturing sand filtration path; the inner cone design of the ceramic filter element and the filter element inner shell, combined with the setting of the liquid inlet gap of the filter element shell and the liquid outlet gap of the filter element inner shell, makes the oil flow rate suddenly increase when flowing through the top of the filter element inner shell, and the pressure at the liquid outlet gap of the bottom ceramic filter element inner shell suddenly decreases. This effect will drive the flow of oil in the inner cone type ceramic filter element assembly, play the effect of accelerating suction and periodic impact, and thus prevent the ceramic filter element from being blocked.

[0011] The present invention utilizes a multi-stage inner-conical ceramic filter assembly, each stage of which provides three-layer filtration of the oil. The ceramic filter element increases the length of the fracturing sand filtration path, providing excellent sand control. This allows the fracturing sand and silt contained in the oil to be completely filtered out before entering the oil well pump, ensuring normal and stable operation of the oil well pump without sand jamming. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a structural schematic diagram of the present invention;

[0013] Figure 2 It is a structural diagram of the inner cone type ceramic filter element assembly.

[0014] In the figure, A-the liquid inlet hole of the outer cylinder of the screen tube, B-the liquid inlet gap of the filter element shell, C-the liquid outlet gap of the inner shell of the filter element, D-the annular space of the oil casing, 1-the oil pipe coupling, 2-the upper joint of the screen tube, 3-the outer cylinder of the screen tube, 4-the ceramic filter element assembly, 5-the lower joint of the screen tube, 6-the casing, 401-the upper cover of the housing, 402-the filter element shell, 403-the ceramic filter element, 404-the filter element inner shell, 405-the lower cover of the housing. DETAILED DESCRIPTION

[0015] The present invention will be further described below in conjunction with the accompanying drawings:

[0016] Depend on Figure 1 、 Figure 2As shown, an internally tapered sand control screen comprises an upper screen joint 2 and a lower screen joint 5. The upper end of the upper screen joint 2 is connected to the oil pipe via a tubing coupling 1. A screen outer tube 3 is threadedly connected between the upper and lower screen joints 2 and 5. The outer tube 3 is provided with a plurality of liquid inlet holes A. Several ceramic filter element assemblies 4 are disposed within the outer tube 3. The upper and lower screen joints 2 and 5 confine these ceramic filter element assemblies 4 within the outer tube 3. Adjacent ceramic filter element assemblies 4 are crimped together.

[0017] The ceramic filter assembly 4 includes a filter housing 402 and a filter inner housing 404, with a ceramic filter 403 disposed therebetween. The outer housing 402 and the inner housing 404 are connected at both ends to the housing upper cover 401 and the housing lower cover 405, respectively, enclosing the ceramic filter 403 between the inner and outer housings. The inner housing 404 is conical, with a smaller inner diameter at the upper end and a larger inner diameter at the lower end. The outer housing 402 is provided with a filter housing liquid inlet slit B, and the inner housing 404 is provided with a filter inner housing liquid outlet slit C. The outer housing liquid inlet slit B is located above the filter inner housing liquid outlet slit C, i.e., the filter inner housing liquid outlet slit C is located at the larger diameter end of the filter inner housing 404, and the outer housing liquid inlet slit B corresponds to the smaller diameter end of the filter inner housing 404. During the crude oil lifting process, negative pressure can be generated at the liquid gap in the filter inner housing, facilitating the entry of crude oil into the sieve tube.

[0018] When the inner cone type sand control pipe is working, an oil casing annular space D is formed between the screen tube outer tube 3 and the casing 6, and the oil enters the ceramic filter element assembly 4 from the screen tube outer tube liquid inlet hole A on the screen tube outer tube 3. During this period, the first filtration is completed through the liquid inlet gap B of the filter element shell, and a very small amount of fracturing sand and silt carried in the oil is blocked outside the liquid inlet gap B of the filter element shell; then the oil enters the ceramic filter element 403 and continues to move downward, and the ceramic filter element 403 completes the second filtration, and the only remaining smaller fracturing sand and silt carried in the oil is completely filtered out; finally, the oil enters the internal conical channel of the ceramic filter element assembly through the liquid outlet gap C of the ceramic filter element inner shell. At this time, the oil no longer contains fracturing sand with silt components, thereby playing a role in preventing sand jam in the oil pump. The filter inner shell 404 of the ceramic filter assembly 4 is tapered, with the outlet slit C on the inner shell 404 positioned below the inlet slit B on the outer shell 402. After entering the ceramic filter assembly 4 through the inlet slit B, the oil passes through the ceramic filter 403 and then enters the tapered channel within the ceramic filter assembly through the outlet slit C. This fully utilizes the height of the ceramic filter 403 to increase the filtration path length and enhance the filtration of silt and sand. Furthermore, due to the tapered shape of the filter inner shell 404, the oil's flow rate suddenly increases as it flows through the top of the filter inner shell 404, while the pressure at the bottom outlet slit C suddenly decreases. This effect drives the oil's flow within the ceramic filter assembly 4, accelerating suction and providing periodic shock, thereby preventing clogging of the ceramic filter 403.

Claims

1. An inner cone type sand control screen pipe, comprising a screen pipe upper joint (2) and a screen pipe lower joint (5), wherein a screen pipe outer cylinder (3) is connected between the screen pipe upper joint (2) and the screen pipe lower joint (5), characterized in that: A plurality of ceramic filter element assemblies (4) are provided inside the screen tube outer cylinder (3); the ceramic filter element assembly (4) comprises a filter element outer shell (402) and a filter element inner shell (404), with a ceramic filter element (403) provided therebetween; the filter element outer shell (402) is provided with a filter element outer shell liquid inlet slit (B), and the filter element inner shell (404) is provided with a filter element inner shell liquid outlet slit (C); the filter element outer shell liquid inlet slit (B) is located above the filter element inner shell liquid outlet slit (C); the filter element inner shell (404) is conical, the filter element inner shell liquid outlet slit (C) is located at the large diameter end of the filter element inner shell (404), and the filter element outer shell liquid inlet slit (B) corresponds to the small diameter end of the filter element inner shell (404); the filter element outer shell (402) and the filter element inner shell (404) are connected at both ends to the housing upper cover (401) and the housing lower cover (405), respectively.

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