Two-way sand prevention circulating well washing valve

Abstract

The invention discloses a bidirectional sand prevention circulating well washing valve, which relates to the technical field of oil field oil extraction tools, and comprises an upper sand prevention screen pipe, a sealing sleeve, a one-way valve, a lower sand prevention screen pipe and a lower plug which are sequentially connected from top to bottom, the lower sand control screen pipe is connected with a lower oil pipe in the oil pipe column through a lower plug, the sealing sleeve is used for sealing and separating an annular space between the oil pipe and a sleeve, liquid of the one-way valve is allowed to flow from bottom to top, and the upper sand control screen pipe and the lower sand control screen pipe are used for filtering passing oil liquid. An inner hole of the oil pipe is separated through the one-way valve, the oil sleeve annulus is separated through the sealing sleeve, well washing fluid only circulates on the upper layer, the flow speed during well washing is guaranteed, and the well washing operation efficiency is improved. Meanwhile, adverse effects such as blockage of the flushing fluid on an oil layer are reduced, the oil content ratio in produced fluid is guaranteed, and the overall benefits of an oil field are improved.

Description

Technical Field

[0001] The invention relates to the technical field of oilfield production tools, in particular to a two-way sand prevention circulation well flushing valve. Background Art

[0002] In thin oil wells, impurities such as sand and wax produced in the well can easily enter the oil pump, increase the running resistance of the oil pump, and in severe cases, block the valve ball, resulting in a shutdown accident. For wells where sand and wax are not serious, filtration tools such as screens are generally not installed under the oil pump. However, as time accumulates, a small amount of sand, wax and other impurities will always enter tools such as gas sand anchors, reducing the overall pump efficiency. In severe cases, sand will bury the oil pipe, making it impossible to pull out the pipe string, so frequent well washing is required. The following problems exist in the well washing process:

[0003] 1. When washing the well, including forward washing and backwashing, because the casing annulus is connected to the oil layer, if the oil layer permeability is high, a large-displacement pump truck is required to return the fluid from the wellhead. Otherwise, a large amount of well washing fluid will penetrate into the oil layer, reducing the efficiency of well washing and blocking the oil layer.

[0004] 2. After the well is washed with excessive well washing fluid, the oil content in the produced fluid decreases within a period of time after pumping is started, reducing the efficiency of the oil field.

[0005] In summary, how to reduce the impact of well washing fluid on the oil layer is a technical problem that technical personnel in this field need to solve urgently. Summary of the invention

[0006] The purpose of the present invention is to provide a two-way sand control circulation well flushing valve to solve the problems existing in the above-mentioned prior art, reduce the impact of the well flushing fluid on the oil layer, ensure the oil content in the produced fluid, and improve the overall efficiency of the oil field.

[0007] To achieve the above object, the present invention provides the following solutions:

[0008] The present invention provides a two-way sand control circulation well flushing valve, comprising an upper sand control screen, a sealing sleeve, a one-way valve, a lower sand control screen and a lower plug which are connected in sequence from top to bottom, wherein the upper sand control screen is connected to an upper oil pipe in an oil pipe column through an upper plug, and the lower sand control screen is connected to a lower oil pipe in the oil pipe column through a lower plug, the sealing sleeve is used for sealing and isolating an annular space between the oil pipe and the casing, the liquid of the one-way valve is allowed to flow from bottom to top, and the upper sand control screen and the lower sand control screen are used for filtering the oil passing through.

[0009] Preferably, the middle part of the inner hole of the upper plug is sealed and the upper and lower parts of the inner hole are internal thread structures, the upper end of the upper plug is connected to the upper oil pipe in the oil pipe string through the internal thread, and the lower end of the upper plug is connected to the upper end of the upper sand control screen through the internal thread.

[0010] Preferably, it further comprises a connecting pipe, the sealing sleeve is sleeved on the outside of the connecting pipe and blocks the annular space between the connecting pipe and the casing, and the lower end of the upper sand control screen is threadedly connected to the upper end of the connecting pipe through a joint.

[0011] Preferably, the lower end of the connecting pipe is threadedly connected to the upper end of the one-way valve.

[0012] Preferably, the lower end of the one-way valve is threadably connected to the upper end of the lower sand control screen pipe through a joint.

[0013] Preferably, the middle part of the inner hole of the lower plug is sealed and the upper and lower parts of the inner hole are internal thread structures, the upper end of the lower plug is connected to the lower end of the upper sand control screen through the internal thread, and the lower end of the lower plug is connected to the lower oil pipe in the oil pipe string through the internal thread.

[0014] Preferably, the wall of the upper sand control screen pipe is provided with sieve holes connecting the external space and the internal through holes.

[0015] Preferably, the wall of the lower sand control screen pipe is provided with screen holes connecting the external space and the internal through holes.

[0016] Compared with the prior art, the present invention has achieved the following technical effects:

[0017] The bidirectional sand-proof circulation well-washing valve of the present invention separates the inner hole of the oil pipe through a one-way valve and separates the annulus of the oil casing through a sealing sleeve, so that the well-washing fluid circulates only in the upper layer, ensuring the flow rate during well-washing and improving the efficiency of well-washing operations. At the same time, it reduces the adverse effects of the well-washing fluid on the oil layer, such as clogging, ensuring the oil content ratio in the produced fluid, and improving the overall benefits of the oil field. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a structural schematic diagram of a bidirectional sand control circulation well flushing valve in the present invention;

[0020] In the figure: 1. upper plug; 2. upper sand control screen; 3. sealing sleeve; 4. one-way valve; 5. lower sand control screen; 6. lower plug. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] The purpose of the present invention is to provide a two-way sand prevention circulation well flushing valve to solve the problems existing in the prior art.

[0023] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] The two-way sand control circulation well washing valve in this embodiment is as follows: Figure 1 As shown, it includes an upper plug 1, an upper sand screen 2, a sealing sleeve 3, a one-way valve 4, a lower sand screen 5 and a lower plug 6 which are connected in sequence from top to bottom, wherein the upper sand screen 2 is connected to the upper oil pipe in the oil pipe string through the upper plug 1, and the lower sand screen 5 is connected to the lower oil pipe in the oil pipe string through the lower plug 6. The sealing sleeve 3 is used to seal and isolate the annular space between the oil pipe and the casing. The liquid in the one-way valve 4 is allowed to flow from bottom to top. The upper sand screen 2 and the lower sand screen 5 are used to filter the oil passing through.

[0025] In this specific embodiment, the middle part of the inner hole of the upper plug 1 is sealed and the upper and lower parts of the inner hole are internal thread structures. The upper end of the upper plug 1 is connected to the upper oil pipe in the oil pipe string through the internal thread, and the lower end of the upper plug 1 is connected to the upper end of the upper sand control screen 2 through the internal thread.

[0026] In this specific embodiment, a connecting pipe is also included. The sealing sleeve 3 is sleeved on the outside of the connecting pipe and blocks the annular space between the connecting pipe and the casing. The lower end of the upper sand control screen pipe 2 is connected to the upper end of the connecting pipe through a joint thread.

[0027] In this specific embodiment, the lower end of the connecting pipe is threadedly connected to the upper end of the one-way valve 4 .

[0028] In this specific embodiment, the lower end of the one-way valve 4 is connected to the upper end of the lower sand control screen 5 through a joint thread.

[0029] In this specific embodiment, the middle of the inner hole of the lower plug 6 is blocked and the upper and lower parts of the inner hole are internal thread structures. The upper end of the lower plug 6 passes through the lower end of the internal thread upper sand screen 2, and the lower end of the lower plug 6 is connected to the lower oil pipe in the oil pipe string through the internal thread. The lower plug 6 makes the lower oil pipe non-conductive, and the oil needs to go through the annular space between the connecting pipe and the casing. The oil passes through the annular space, enters the lower sand screen 5, and then passes through the inner hole of the one-way valve 4 to reach the upper part of the one-way valve 4, and cannot fall back, waiting for the oil pump to produce the ground.

[0030] In this specific embodiment, the wall of the upper sand control screen pipe 2 is provided with screen holes communicating with the external space and the internal through holes.

[0031] In this specific embodiment, the wall of the lower sand control screen pipe 5 is provided with screen holes communicating with the external space and the internal through holes.

[0032] During use, the bidirectional sand control circulation well-washing valve in this embodiment is installed in the middle and upper part of the oil pipe column, and the installation order from top to bottom is the box plug, oil pipe (1 to 2 pieces), the bidirectional sand control circulation well-washing valve in this embodiment, oil pipe (2 to 5 pieces, determined according to the sand production situation in the well), gas sand anchor, and oil pump. When washing the well, the washing fluid is pumped into the well. Due to the presence of the one-way valve 4, the inner hole of the oil pipe is separated, and the sealing sleeve 3 separates the oil casing annulus, so that the washing fluid circulates only in the upper layer, achieving the purpose of washing the well without polluting the formation.

[0033] The specific working principle is as follows:

[0034] 1) The main structure is a flow check valve 4. Between the check valve 4 and the inner hole of the casing, the annular space between the oil pipe and the casing is sealed by the "oil and casing annular space sealing sleeve 3" to form an upper and lower space. The lower layer is connected to the oil layer, and the upper layer includes the sucker rod string and the oil pipe string above the oil pump.

[0035] 2) The oil in the oil layer can pass through the one-way valve 4 and enter the upper space, and cannot fall back.

[0036] 3) The screen pipe under the one-way valve 4 performs preliminary filtration on the produced fluid of the oil layer, thus protecting the one-way valve 4 to the greatest extent from the influence of impurities such as sand and wax in the oil layer.

[0037] 4) The screen pipe on the top of the check valve 4 filters the oil again to improve the working environment of the oil pump, gas sand anchor, etc. It also prevents the impurities in the oil from settling and prevents the sand from burying the check valve 4, thus extending the normal working cycle.

[0038] 5) During well washing, including forward washing and backwashing, the well washing fluid can only circulate in the upper layer under the blockage of the one-way valve 4 and the sealing sleeve 3, thereby ensuring the flow rate and well washing effect.

[0039] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A two-way sand control circulation well flushing valve, characterized by: It comprises an upper sand control screen, a sealing sleeve, a one-way valve, a lower sand control screen and a lower plug connected in sequence from top to bottom, wherein the upper sand control screen is connected to the upper oil pipe in the oil pipe string through the upper plug, and the lower sand control screen is connected to the lower oil pipe in the oil pipe string through the lower plug, the sealing sleeve is used to seal and cut off the annular space between the oil pipe and the casing, the liquid of the one-way valve is allowed to flow from bottom to top, and the upper sand control screen and the lower sand control screen are used to filter the oil passing through.

2. The two-way sand control circulation well flushing valve according to claim 1 is characterized in that: The middle part of the inner hole of the upper plug is sealed and the upper and lower parts of the inner hole are internal thread structures. The upper end of the upper plug is connected to the upper oil pipe in the oil pipe string through the internal thread, and the lower end of the upper plug is connected to the upper end of the upper sand control screen through the internal thread.

3. The two-way sand control circulation well flushing valve according to claim 2 is characterized in that: It also includes a connecting pipe, the sealing sleeve is sleeved on the outside of the connecting pipe and blocks the annular space between the connecting pipe and the casing, and the lower end of the upper sand control screen is connected to the upper end of the connecting pipe through a joint thread.

4. The two-way sand control circulation well flushing valve according to claim 3 is characterized in that: The lower end of the connecting pipe is threadedly connected to the upper end of the one-way valve.

5. The two-way sand control circulation well flushing valve according to claim 4 is characterized in that: The lower end of the one-way valve is threadably connected to the upper end of the lower sand control screen pipe through a joint.

6. The two-way sand control circulation well flushing valve according to claim 5 is characterized in that: The middle part of the inner hole of the lower plug is sealed and the upper and lower parts of the inner hole are internal thread structures. The upper end of the lower plug is connected to the lower end of the lower sand control screen through the internal thread, and the lower end of the lower plug is connected to the lower oil pipe in the oil pipe string through the internal thread.

7. The bidirectional sand control circulation well flushing valve according to claim 1 is characterized in that: The pipe wall of the upper sand control screen pipe is provided with screen holes communicating with the external space and the internal through holes.

8. The two-way sand control circulation well flushing valve according to claim 1 is characterized in that: The pipe wall of the lower sand control screen pipe is provided with screen holes communicating with the external space and the internal through holes.

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