Anti-backflow eccentric water distributor

Abstract

The utility model belongs to the field of downhole tools of oil field oil production engineering, and particularly relates to an anti-backflow eccentric water distributor. The backflow-preventing eccentric water distributor comprises a water distribution main body, the water distribution main body is provided with a water injection hole communicated with an eccentric hole, the water distribution main body is sleeved with an annular elastic sleeve covering the water injection hole, and the inner perimeter of the annular elastic sleeve is smaller than the corresponding outer perimeter of the water injection hole of the water distribution main body. The annular elastic sleeve covering the water injection hole is arranged at the water injection hole of the water distribution main body, and the inner perimeter of the annular elastic sleeve is smaller than the corresponding outer perimeter of the water injection hole of the water distribution main body, so that the annular elastic sleeve is in an expanded state; during water injection, injected water ejects open the annular elastic sleeve through the water injection hole and enters an oil sleeve annulus and a stratum; when injection is stopped, the annular elastic sleeve blocks the water injection hole under the action of resilience force, the water injection hole is closed, and the backflow prevention function is achieved. The anti-backflow structure of the anti-backflow eccentric water distributor is simple in design, the structure of the water distributor is slightly changed, and the manufacturing cost is low.

Description

Technical Field

[0001] The utility model belongs to the field of downhole tools for oilfield production engineering, and specifically relates to an anti-backspitting eccentric water distributor. Background Art

[0002] The eccentric water distributor is one of the downhole tools for quantitative water injection in layers according to the different water absorption capacity of the oil layer. During normal water injection, the water injection string is equipped with a packer that divides the oil layer into several water injection layers after setting, and an eccentric water distributor corresponding to each water injection layer.

[0003] The structure of the eccentric water distributor generally includes an upper joint, an upper connecting sleeve, a water distribution body, a lower connecting sleeve and a lower joint connected in sequence from top to bottom. An upper guide body is provided in the upper connecting sleeve between the upper joint and the water distribution body, and a lower guide body is provided in the lower connecting sleeve between the water distribution body and the lower joint. The center of the water distribution body has a main channel extending up and down, and the pipe wall of the main channel is provided with a side hole extending up and down. The bottom of the side hole is connected to the main channel, and the water distribution body is also provided with a water injection hole connected to the side hole. When in use, the plug is delivered into the side hole, a water nozzle is installed at the bottom of the plug, and a water outlet hole is provided on the plug shell. The injected water enters from the main channel, passes through the water nozzle, the water outlet hole of the plug and the water injection hole of the water distribution body in sequence, and then enters the oil casing annulus, and then enters the formation.

[0004] If the eccentric water distributor does not have an anti-backflow function, the water injection holes will always remain unobstructed. When injection is stopped, when the pressure of the water injection string is lower than the formation pressure, solid impurities in the formation will flow back into the water injection string through the water injection holes of the water distribution body, causing contamination of the water injection string, resulting in the deposition of solid impurities in the water injection string and test obstruction.

[0005] The Chinese utility model patent with the announcement date of August 31, 2016 and the announcement number of CN205532529U discloses a piston-controlled anti-backflow eccentric water distributor, which includes a water distribution body, on which a side hole for installing a plug and a water injection hole connected to the side hole are provided, and a piston and a spring are sleeved on the outside of the water distribution body to control the opening and closing of the water injection hole. During water injection, the injected water passes through the plug nozzle and the water injection hole of the water distribution body and acts on the piston, pushing the piston downward and compressing the spring. When the thrust is greater than the upward force of the spring, the piston begins to move downward, opening the water injection channel, and the injected water enters the annulus of the oil casing and is injected into the formation. After pressure relief or well shut-in and injection is stopped, there is no pressure in the oil pipe. At this time, the piston is not subjected to the downward thrust, but only to the upward force of the spring. The piston resets upward, closes the water injection channel, seals the water distributor, and prevents the formation backflow from entering the water distributor or the inside of the pipe column.

[0006] The Chinese utility model patent with the announcement date of April 19, 2019 and the announcement number of CN208763632U discloses an anti-back-spitting eccentric water distributor, including a water distribution body, on which an eccentric hole and a water injection hole are arranged, and an anti-back-spitting valve is installed on the water injection hole. The anti-back-spitting valve includes a pressure cap, a check spring and a sealing ball. When injecting water, the injected water pushes the sealing ball that seals the water injection hole of the water distribution body, and the anti-back-spitting valve opens. The injected water enters the casing annulus and the formation through the plug nozzle, the water injection hole of the water distribution body, and the anti-back-spitting valve. When the injection is stopped, the anti-back-spitting valve is closed under the action of the check spring, and the formation fluid or mud and sand cannot reversely enter the water distributor, ensuring the smooth flow of the oil pipe space in the well.

[0007] Although the above eccentric water distributors all have the anti-spitting function, they need to use complex structures such as pistons and matching springs, anti-spitting valves, etc., which greatly modify ordinary water distributors and have high manufacturing costs. Utility Model Content

[0008] The utility model aims to provide an anti-back-spitting eccentric water distributor to solve the problems of complex anti-back-spitting structure design and high manufacturing cost of the existing anti-back-spitting eccentric water distributor.

[0009] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0010] An anti-back-spitting eccentric water distributor comprises a water distribution body, wherein the water distribution body has a water injection hole connected to the eccentric hole, and an annular elastic sleeve covering the water injection hole is mounted on the water distribution body at the water injection hole position, and the inner circumference of the annular elastic sleeve is smaller than the corresponding outer circumference of the water distribution body at the water injection hole position.

[0011] The utility model belongs to an improved invention creation, in which an annular elastic sleeve covering the water injection hole is arranged at the water injection hole of the water distribution body, and the inner circumference of the annular elastic sleeve is smaller than the corresponding outer circumference of the water injection hole of the water distribution body, so as to ensure that the annular elastic sleeve is in an expanded state; when injecting water, the injected water pushes the annular elastic sleeve through the water injection hole and enters the oil casing annulus and the formation; when the injection is stopped, the annular elastic sleeve blocks the water injection hole under the action of the rebound force, and the water injection hole is closed, so as to realize the anti-back-spitting function. The anti-back-spitting structure design of the anti-back-spitting eccentric water distributor is simple, the modification of the water distributor structure is small, and the manufacturing cost is low.

[0012] Preferably, the anti-back-vomiting eccentric water distributor is provided with a limiting structure for limiting the upward and downward deviation of the annular elastic sleeve.

[0013] Further preferably, the anti-back-vomiting eccentric water distributor includes an upper connecting sleeve connecting an upper joint and the water distribution body, and the limiting structure includes an upper limit structure formed by the lower end surface of the upper connecting sleeve for limiting the upward displacement of the annular elastic sleeve.

[0014] More preferably, the lower end surface of the upper connecting sleeve is provided with an inner chamfer.

[0015] Most preferably, the radial dimension of the inner chamfer is smaller than the wall thickness of the annular elastic sleeve.

[0016] Further preferably, the limiting structure comprises a lower limiting step provided on the water distribution body below the annular elastic sleeve for limiting the downward displacement of the annular elastic sleeve.

[0017] More preferably, the annular elastic sleeve is spaced apart from the lower limiting step.

[0018] Preferably, the water injection hole is correspondingly arranged at the axial middle part of the annular elastic sleeve.

[0019] Preferably, the outer peripheral surface corresponding to the position of the water injection hole on the water distribution body is an outer cylindrical surface.

[0020] Preferably, the annular elastic sleeve is an annular rubber sleeve. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a structural schematic diagram of an anti-backspitting eccentric water distributor according to an embodiment of the utility model;

[0022] Figure 2 for Figure 1 AA section view;

[0023] Figure 3 for Figure 1 A partial enlarged view of the boxed part;

[0024] Among them, 1-upper joint; 2-upper connecting sleeve; 3-upper guide body; 4-water distribution body; 5-lower connecting sleeve; 6-lower guide body; 7-lower joint; 8-side hole; 9-water outlet hole; 10-annular elastic sleeve; 11-limiting step; 12-outer cylindrical surface; 20-inner chamfer. DETAILED DESCRIPTION

[0025] The purpose of the utility model is to provide an anti-back-spitting eccentric water distributor, which does not change the internal structure of the eccentric water distributor. The main technical concept is to cover an annular elastic sleeve outside the water injection hole of the water distribution body, and the inner circumference of the annular elastic sleeve is smaller than the corresponding outer circumference of the water injection hole of the water distribution body, thereby ensuring that the annular elastic sleeve is in an expanded state. When the water injection pressure is greater than the rebound force of the annular elastic sleeve, the injected water pushes the annular elastic sleeve to realize the water injection function; when the injection is stopped, the annular elastic sleeve covers and blocks the water injection hole under the action of the rebound force, thereby realizing the anti-back-spitting function.

[0026] Furthermore, by optimizing the limiting structure, the shape of the annular elastic sleeve, etc., the performance reliability of the water injection and anti-backspitting functions can be further improved. In this way, the anti-backspitting function can be achieved by simply modifying the ordinary eccentric water distributor. In the actual engineering application process, it has the characteristics of small changes, simple structure, reliable performance and low cost.

[0027] The implementation process of the utility model is described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] The utility model of the anti-backspitting eccentric water distributor is as follows Figure 1 to Figure 3 As shown, it includes an upper joint 1, an upper connecting sleeve 2, an upper guide body 3, a water distribution body 4, a lower connecting sleeve 5, a lower guide body 6, and a lower joint 7, wherein the upper connecting sleeve 2 is connected between the upper joint 1 and the water distribution body 4, and the lower connecting sleeve 5 is connected between the water distribution body 4 and the lower joint 7. The upper guide body 3 is arranged on the inner side of the upper connecting sleeve 2 and is located between the upper joint 1 and the water distribution body 4, and the lower guide body 6 is arranged on the inner side of the lower connecting sleeve 5 and is located between the water distribution body 4 and the lower joint 7.

[0029] The utility model mainly relates to the improvement of the water distribution body 4, the structure of the upper joint 1, the upper connecting sleeve 2, the upper guide body 3, the lower connecting sleeve 5, the lower guide body 6, the lower joint 7 and the connection relationship with the corresponding parts are the existing technology, and are not limited to Figure 1 specific implementation circumstances.

[0030] The water distribution body 4 realizes water injection into the corresponding formation and meets relevant test requirements such as pressure measurement. The water distribution body 4 has a main channel located in the center and a side hole 8 connected to the main channel. The water distribution body 4 is also provided with a water injection hole 9 connected to the side hole 8. The side hole 8 is used to install a plug. A water nozzle is installed at the bottom of the plug. A water outlet hole is provided on the plug shell. When injecting water, the injected water enters the oil casing annulus through the water injection channel formed by the main channel, the plug nozzle, the plug outlet hole and the water injection hole 9 of the water distribution body 4.

[0031] like Figure 2 , Figure 3 As shown, an annular elastic sleeve 10 capable of covering the water injection hole 9 is mounted on the water distribution body 4 at the water injection hole 9. The annular elastic sleeve 10 has a certain elasticity, and its inner circumference is smaller than the corresponding outer circumference of the water distribution body 4 at the water injection hole 9. In this way, the annular elastic sleeve 10 is in an expanded state, and it clings to and blocks the water injection hole 9 under the action of its own resilience. During water injection, the injected water pushes the annular elastic sleeve 10 through the water injection hole 9 and enters the corresponding oil layer. After stopping injection, the annular elastic sleeve 10 re-blocks the water injection hole 9 under the action of its own resilience, preventing the backflow of formation water and solid impurities, and achieving anti-vomiting.

[0032] In order to prevent the annular elastic sleeve 10 from deviating from the predetermined position range after multiple water injection and stop operations, that is, the annular elastic sleeve 10 itself cannot effectively cover the water injection hole 9, a limiting structure is provided on the eccentric water distributor to limit the upward and downward deviation of the annular elastic sleeve 10.

[0033] like Figure 3 As shown, in order to limit the upward displacement of the annular elastic sleeve 10, the lower end surface of the upper connecting sleeve 2 is used as the upper limit structure of the annular elastic sleeve. After the upper end of the annular elastic sleeve 10 contacts the lower end surface of the upper connecting sleeve 2, the annular elastic sleeve 10 reaches its upward displacement limit position. In order to limit the downward displacement of the annular elastic sleeve 10, a limiting step 11 is provided below the annular elastic sleeve 10 on the water distribution body 4 to limit the downward displacement of the annular elastic sleeve 10. After the lower end of the annular elastic sleeve 10 contacts the limiting step 11, the annular elastic sleeve 10 reaches its downward displacement limit position. By setting the above limiting structure, it can be ensured that even if the annular elastic sleeve deviates up and down, the water injection and anti-vomiting functions can still be achieved within the range of its up and down displacement.

[0034] Furthermore, if Figure 3 As shown, the lower end surface of the upper connecting sleeve 2 is provided with an inner chamfer 20, so that when the annular elastic sleeve 10 deflects upward, the inner chamfer 20 provides an inner chamfer space to guide the annular elastic sleeve 10 to move inward instead of easily crossing the lower end surface of the upper connecting sleeve 2. At the same time, the radial dimension of the inner chamfer 20 is smaller than the sleeve wall thickness of the annular elastic sleeve 10, and the upper end of the annular elastic sleeve 10 is prevented from squeezing into the inner chamfer space, thereby not causing adverse effects on the outflow of water from the upper end of the annular elastic sleeve 10.

[0035] At the same time, the annular elastic sleeve 10 and the limiting step 11 are arranged at intervals, which facilitates water to flow from the lower end of the annular elastic sleeve 10 through the interval into the annulus of the oil casing.

[0036] The axial middle part of the annular elastic sleeve 10 fits with the corresponding water injection hole 9. The above design ensures that the annular elastic sleeve 10 has a certain coverage range in the up and down directions, and has good sealing reliability for the water injection hole 9. Further in combination with the above limiting structure of the annular elastic sleeve 10, the reliability of the water injection and anti-spitting functions can be better guaranteed.

[0037] The utility model has no special requirements on the shape of the water distribution body 4, such as Figure 2 As shown, the outer peripheral surface of the water injection hole 9 of the water distribution body 4 is an outer cylindrical surface 12, and the outer diameter of the outer cylindrical surface 12 is smaller than the outer diameter of the limiting step 11. In addition, the annular elastic sleeve can be in the form of an annular rubber sleeve, which is a conventional material in the field of oil field downhole tools, so the cost is low and the performance is reliable.

[0038] The use process of the utility model of the anti-back-spitting eccentric water distributor is as follows: during the process of going down the well, the annular elastic sleeve 10 is tightly attached to the outer cylindrical surface 12 of the water distribution body 4, closing the water injection hole 9. During water injection, the injected water pushes the annular elastic sleeve 10 through the water injection hole 9 and enters the oil layer; when the water injection is stopped, when the pressure of the water injection pipe column is lower than the oil layer pressure, the annular elastic sleeve 10 is tightly attached to the outer cylindrical surface 12 of the water distribution body 4 under the action of elastic force, blocking the water injection hole 9. The water injection hole 9 is closed, and formation water and solid impurities cannot enter the pipe column, avoiding pipe column pollution.

Claims

1. An anti-backspitting eccentric water distributor, comprising a water distribution body, wherein the water distribution body has a water injection hole connected to the eccentric hole, characterized in that: An annular elastic sleeve covering the water injection hole is mounted on the water distribution body, and the inner circumference of the annular elastic sleeve is smaller than the corresponding outer circumference of the water injection hole of the water distribution body.

2. The anti-backspitting eccentric water distributor according to claim 1, characterized in that: The anti-back-spitting eccentric water distributor is provided with a limiting structure for limiting the upward and downward deviation of the annular elastic sleeve.

3. The anti-backspitting eccentric water distributor according to claim 2, characterized in that: The anti-back-spitting eccentric water distributor comprises an upper connecting sleeve connecting an upper joint and the water distribution body, and the limiting structure comprises an upper limit structure formed by the lower end surface of the upper connecting sleeve to limit the upward displacement of the annular elastic sleeve.

4. The anti-backspitting eccentric water distributor according to claim 3, characterized in that: The lower end surface of the upper connecting sleeve is provided with an inner chamfer.

5. The anti-backspitting eccentric water distributor according to claim 4, characterized in that: The radial dimension of the inner chamfer is smaller than the wall thickness of the annular elastic sleeve.

6. The anti-backspitting eccentric water distributor according to claim 2, characterized in that: The limiting structure comprises a lower limiting step which is arranged on the water distribution body below the annular elastic sleeve and which limits the downward displacement of the annular elastic sleeve.

7. The anti-backspitting eccentric water distributor according to claim 6, characterized in that: The annular elastic sleeve is arranged at an interval from the lower limit step.

8. The anti-backspitting eccentric water distributor according to any one of claims 1 to 7, characterized in that: The water injection hole is correspondingly arranged at the axial middle part of the annular elastic sleeve.

9. The anti-backspitting eccentric water distributor according to claim 1, characterized in that: The outer peripheral surface corresponding to the position of the water injection hole on the water distribution body is an outer cylindrical surface.

10. The anti-backspitting eccentric water distributor according to claim 1, characterized in that: The annular elastic sleeve is an annular rubber sleeve.

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