Sacrificial screen pipe capable of improving filling efficiency

Abstract

A sacrifice screen pipe capable of improving filling efficiency comprises a screen pipe body, a liquid swelling packer is arranged in the screen pipe body, and when the liquid swelling packer is in an initial state, a flow guide gap exists between the liquid swelling packer and the inner wall of the screen pipe body; after the packer capable of expanding when encountering liquid is tripped into a shaft, the packer capable of expanding when encountering liquid is in an expanding state from an initial state, and a flow guide gap between the packer and the inner wall of the screen pipe body is sealed. The utility model has the following technical effects: firstly, when filling liquid carrying particles is injected into the annulus of the shaft, the radial flow guide holes can generate larger flow, so that more particles can be carried to remain at the toe part of the shaft, the toe part space can be filled with the particles more easily, and the particles are filled and extruded more compactly; and secondly, the packer capable of expanding when encountering liquid is arranged, an expansion assembly expands when encountering liquid after well completion, a flow-back channel in the screen pipe body is completely sealed, and therefore the problem that the water content of produced liquid is increased due to water outlet of the stratum of the toe of the shaft is thoroughly solved.

Description

Technical Field

[0001] The utility model patent belongs to the technical field of oil extraction, and relates to a screen pipe used for well completion, in particular to a sacrificial screen pipe that can improve filling efficiency. Background Art

[0002] "Continuous packer water control technology" has been widely used in the field of oil extraction technology. Referring to Chinese patents 201910623000X, a sealing method and completion structure for injection and production in the same well, 2019104892759, an artificial well wall formation method and completion structure for preventing mud production or channeling in mudstone layers, 2021111193667, a continuous seal for improving the axial anti-channeling capability in the downhole annulus, 202120468829X, a water injection well, 2023113127387, a method for reducing water and increasing oil production by filling seals with particles in oil and gas wells in fractured oil and gas reservoirs, and other public documents, the following method is usually used to form a "continuous seal" during the completion operation: first, a central pipe string with a screen pipe is lowered into the wellbore, and then a filling fluid carrying sealing particles is injected into the wellbore annulus between the well wall and the central pipe string. The filling fluid is returned through the screen pipe and the central pipe string or absorbed by the formation, and the sealing particles are blocked by the screen of the screen pipe and retained in the wellbore annulus to form a "continuous seal". Similarly, similar filling operations can be used to fill the wellbore annulus with gravel or other particles.

[0003] The above method has the following technical problems: for wellbores with long production sections (for example, more than 500 meters), due to the large number of screens in the production section, it has a strong backflow and flowback capacity. Therefore, most of the filling fluid injected through the wellbore annulus is returned by the screens in the part of the production section near the wellhead. Therefore, it is difficult to guide the filling fluid carrying filling particles to the toe end of the central pipe string in the production section, resulting in unsatisfactory filling effect in the deep production section, especially at the toe end of the central pipe string. There are cavities between the filling particles or the filling is not tight enough, which leads to poor water control effect after production. In order to solve the above technical problems, an ordinary screen without flow control function can be used at the toe end of the central pipe string. This ordinary screen has a large flow diversion capacity and can divert the filling fluid injected into the annulus to the toe end of the central pipe string. However, since the ordinary screen has uncontrollable two-way flow diversion capacity and does not have automatic water control capability, once water appears in the formation corresponding to the toe end after production, the water will directly enter the central pipe string without hindrance, resulting in a serious increase in the water content of the oil well production fluid. Utility Model Content

[0004] The purpose of this utility model patent is to overcome the defects of the existing technology and provide a sacrificial screen that can improve the filling efficiency, so as to solve the problems of unsatisfactory filling effect and water outflow from the toe of the wellbore affecting the water content of the produced fluid during the completion operation.

[0005] To achieve the above purpose, this utility model patent adopts the following technical solutions:

[0006] A sacrificial screen that can improve filling efficiency includes a screen body, wherein a liquid-expanding packer is provided inside the screen body, wherein, in an initial state, the liquid-expanding packer has a guide gap between the packer and the inner wall of the screen body; after the liquid-expanding packer is lowered into the wellbore, it expands from the initial state to an expanded state when it encounters liquid, thereby sealing the guide gap between the packer and the inner wall of the screen body.

[0007] Furthermore, the sieve tube body is a tubular structure, with a cylindrical screen provided circumferentially on the outer wall, and sieve holes provided on the screen; radial guide holes are provided at the position of the outer wall of the sieve tube body covered by the screen.

[0008] Furthermore, the outer wall of the sieve tube body is further provided with a sieve fixing ring, and the sieve is clamped between the sieve fixing rings.

[0009] Furthermore, the liquid-expandable packer includes a carrier and an expansion rubber tube, wherein the carrier is an axial structure coaxially arranged inside the screen body; the expansion rubber tube is annularly arranged outside the carrier.

[0010] Furthermore, the liquid-expandable packer also includes a baffle, which is a circular ring structure and is arranged on the carrier at positions on both sides of the expansion rubber cylinder to limit the expansion rubber cylinder; the outer diameter of the baffle is consistent with the outer diameter of the expansion rubber cylinder.

[0011] Furthermore, the liquid-swellable packer further includes a packer straightening ring. There are at least two packer straightening rings, which are arranged on the carrier at both sides of the baffle. Axial guide holes are also provided on the packer straightening rings.

[0012] Furthermore, the liquid-swellable packer also includes a packer positioning ring, which is arranged on the carrier, and the outer diameter of the packer positioning ring is smaller than the inner diameter of the screen body; a radial threaded countersunk hole is provided on the outer circumference of the packer positioning ring.

[0013] Furthermore, a packer fixing ring is provided on the circumferential outer side of the screen tube body, and radial bolt through holes that are consistent with the threaded countersunk holes of the packer fixing ring are provided at positions corresponding to the packer fixing ring and the screen tube body at positions corresponding to the packer fixing ring, and limiting bolts are provided in the bolt through holes and the threaded countersunk holes.

[0014] Furthermore, the first flow cross-section formed by the guide slit, the second flow cross-section formed between the packer positioning ring and the inner wall of the screen tube body, and the third flow cross-section formed by the axial guide hole provided on the packer straightening ring, all have flow cross-sectional areas that are not less than the predetermined flow cross-sectional requirements.

[0015] Furthermore, outer side surfaces of the packer straightening ring, the packer positioning ring and / or the baffle are provided with chamfers.

[0016] This utility model patent is a sacrificial screen that can improve filling efficiency and has the following technical effects: First, when injecting filling fluid carrying particles into the wellbore annulus, the radial guide holes can generate a larger flow rate, thereby carrying more particles to be retained at the toe of the wellbore, making it easier for the particles to fill the toe space and making the filling and squeezing between the particles more compact. Second, by setting a liquid expansion packer, the expansion component expands when it encounters liquid after well completion, completely sealing the return channel inside the screen body, thereby completely solving the problem of increased water content in the produced fluid caused by water coming out of the formation at the toe of the wellbore. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a partial cross-sectional view of a sacrificial screen tube that can improve filling efficiency in an embodiment of the present utility model;

[0018] Figure 2 This is a schematic diagram of the liquid flow direction of the expansion rubber cylinder 2-1 before expansion in the embodiment of the present utility model;

[0019] Figure 3 This is a schematic diagram of the liquid flow direction after the expansion rubber cylinder 2-1 is fully expanded in the embodiment of the present utility model.

[0020] Explanation of the accompanying symbols: screen body 1, screen 1-1, screen hole 1-2, radial guide hole 1-3, screen fixing ring 1-4, liquid expansion packer 2, carrier 2-0, expansion rubber cylinder 2-1, packer straightening ring 2-2, packer positioning ring 2-3, packer fixing ring 2-4, limit bolt 2-5, baffle 2-6, axial guide hole 2-7. DETAILED DESCRIPTION

[0021] The following is combined with Figures 1 to 3 , further illustrating a specific embodiment of the utility model patent a sacrificial screen tube that can improve filling efficiency. The utility model patent a sacrificial screen tube that can improve filling efficiency is not limited to the description of the following embodiments.

[0022] This embodiment discloses a sacrificial screen that can improve filling efficiency, such as Figure 1-3 As shown, the sacrificial screen that can improve the filling efficiency includes a screen body 1, wherein the screen body 1 is provided with a liquid expansion packer 2, wherein, as shown in FIG. Figure 2 As shown, in the initial state, there is a guide gap W1 between the liquid-expandable packer 2 and the inner wall of the screen body 1; Figure 3 As shown, after the liquid-expandable packer 2 is lowered into the wellbore, it expands from its initial state to an expanded state upon contact with liquid, thereby sealing the diversion gap W1 between the packer and the inner wall of the screen body 1 .

[0023] Specifically, during well completion operations in the prior art, the central tubular string lowered into the wellbore typically consists of a blind pipe and a screen. The sacrificial screen disclosed in this embodiment, which can improve filling efficiency, is applied to the position closest to the toe of a central tubular string composed of multiple pipe sections. The sacrificial screen, which can improve filling efficiency, includes a screen body 1. The front end (toe end) of the screen body 1 is provided with radial guide holes 1-3 with a relatively high flow rate. These radial guide holes 1-3 are straight-through and do not require an ICD or AICD valve. After the center pipe string is lowered into the wellbore, when the filling fluid carrying particles is injected into the wellbore annulus, the radial guide holes 1-3 can generate a larger flow rate, thereby returning the filling fluid in the wellbore annulus to the center pipe string and back out of the wellbore, and then the filling fluid with a larger flow rate can carry more particles to be retained at the toe of the wellbore (and the deeper position of the wellbore production section), so that the particles can more easily fill the toe space (and the deeper space of the wellbore production section); at the same time, the larger flow rate can also generate greater pressure, which can make the filling and squeezing between the particles more compact. However, after the well is completed and put into production using the above technical solution, once the formation at the toe of the wellbore leaks, since the radial guide holes 1-3 of the screen body 1 are in a straight-through mode, if the liquid-expanding packer 2 used in this embodiment is not provided, a large amount of leakage produced by the formation will inevitably be introduced into the center pipe string and the wellhead, thereby increasing the water content in the produced fluid. In this embodiment, a liquid-expandable packer 2 is provided. After completion, the expansion component (e.g., expansion rubber sleeve 2-1) in the liquid-expandable packer 2 expands upon contact with liquid (e.g., fully expands within 5-10 hours). The expanded expansion component completely seals the flowback channel within the sieve body 1 of the sacrificial sieve, which improves filling efficiency, thereby completely resolving the problem of increased water content in the produced fluid caused by water production at the toe of the wellbore. The "sacrificial" in the name of the sacrificial sieve, which improves filling efficiency, means this: once the expansion component seals the flowback channel within the sieve body 1, the flowback channel cannot be controlled to open again, and the sieve cannot participate in subsequent production processes. Instead, it can only be used once during the completion phase to fill particles into the wellbore. This is called "sacrificial." It can be seen that the concept of this technical solution is to improve the filling efficiency and effectiveness of particles in the wellbore annulus by "sacrificing" the sieve.

[0024] As an optional technical solution, the screen tube body 1 is a tubular structure, with a cylindrical screen 1-1 circumferentially arranged on the outer wall, and screen holes 1-2 are arranged on the screen 1-1; radial guide holes 1-3 are arranged at the position of the outer wall of the screen tube body 1 covered by the screen 1-1.

[0025] Specifically, a male buckle and a female buckle are provided at both ends of the screen tube body 1, respectively, for connecting with other adjacent pipe strings or toe closure devices in front and behind; the diameter of the sieve holes 1-2 of the screen 1-1 is smaller than the diameter of the particles, thereby preventing the particles from flowing into the interior of the screen tube body 1 through the radial guide holes 1-3; the radial guide holes 1-3 can be set with sufficient flow area according to flow requirements.

[0026] As an optional technical solution, the outer wall of the screen tube body 1 is further provided with screen fixing rings 1-4, and the screen 1-1 is clamped between the screen fixing rings 1-4.

[0027] Specifically, the screen fixing rings 1-4 are fixedly mounted on the outer wall of the screen pipe body 1 by welding, clamping, or bolting. The screen 1-1 is sandwiched between the two screen fixing rings 1-4, thereby securing the screen 1-1 outside the circumference of the screen pipe body 1. A certain distance is maintained between the screen 1-1 and the outer wall of the screen pipe body 1 to facilitate the passage of downhole fluid.

[0028] As an optional technical solution, the liquid-expandable packer 2 includes a carrier 2-0 and an expansion rubber cylinder 2-1, wherein the carrier 2-0 is an axial structure coaxially arranged inside the screen body 1; the expansion rubber cylinder 2-1 is arranged on the outside of the carrier 2-0.

[0029] Specifically, the carrier is an axial structure, coaxially arranged with the screen tube body 1 and located inside the screen tube body 1. The expansion rubber cylinder 2-1 is arranged around the outer circumference of the carrier 2-0. The interior of the expansion rubber cylinder 2-1 is in contact with the outer circumference of the carrier 2-0. In the initial state, a certain distance is maintained between the outer side of the expansion rubber cylinder 2-1 and the interior of the screen tube body 1, forming a guide gap W1.

[0030] As an optional technical solution, the liquid-expandable seal 2 also includes a baffle 2-6, which is a circular ring structure and is arranged on the carrier 2-0 at positions on both sides of the expansion rubber cylinder 2-1 to limit the expansion rubber cylinder 2-1; the outer diameter of the baffle 2-6 is consistent with the outer diameter of the initial position of the expansion rubber cylinder 2-1.

[0031] Specifically, two baffles 2-6 are fixed to the carrier 2-0, forming an annular groove structure, within which the expansion rubber sleeve 2-1 is disposed. When the liquid-expandable packer 2 is in its initial state, the outer diameter of the baffles 2-6 coincides with that of the expansion rubber sleeve 2-1. When the expansion rubber sleeve 2-1 expands upon contact with liquid, the baffles 2-6 prevent the expansion rubber sleeve 2-1 from expanding axially toward both ends, ensuring that it expands only radially. This results in a more effective expansion effect and facilitates better closure of the diversion gap W1.

[0032] As an optional technical solution, the liquid-expandable packer 2 also includes a packer straightening ring 2-2. The number of the packer straightening rings 2-2 is at least two, and the rings are arranged on the carrier 2-0 at both sides of the baffle 2-6; the packer straightening ring 2-2 is also provided with an axial guide hole 2-7.

[0033] Specifically, the purpose of providing the packer centering ring 2-2 is to ensure that the liquid-expandable packer 2 can be coaxially arranged with the screen body 1, thereby ensuring that the expansion rubber sleeve 2-1 can be evenly pressed against the interior of the screen body 1 during expansion, thereby achieving a better expansion effect and helping to better close the diversion slot W1. Preferably, the baffle 2-6 should maintain a certain distance from the packer centering ring 2-2 to avoid blocking the axial diversion hole 2-7.

[0034] As an optional technical solution, the liquid-swellable packer 2 also includes a packer positioning ring 2-3, which is arranged on the carrier 2-0. The outer diameter of the packer positioning ring 2-3 is smaller than the inner diameter of the screen body 1; a radial threaded countersunk hole is provided on the outer side of the circumference of the packer positioning ring 2-3.

[0035] Specifically, the outer diameter of the packer locating ring 2-3 is smaller than the inner diameter of the screen body 1, ensuring that a second guide slot W2 is retained between the two as a flowback channel for the center pipe string. A radial threaded countersunk hole is provided on the outer circumference of the packer locating ring 2-3 to position and secure the liquid-swellable packer 2 within the screen body 1.

[0036] As an optional technical solution, a packer fixing ring 2-4 is further provided on the circumferential outer side of the screen tube body 1, and radial bolt through holes that are consistent with the threaded countersunk holes of the packer fixing ring 2-4 are provided at positions corresponding to the packer fixing ring 2-4 and the screen tube body 1, and limiting bolts 2-5 are provided in the bolt through holes and the threaded countersunk holes.

[0037] Specifically, the packer fixing ring 2-4 can be fixed to the outer circumference of the screen body 1 by means of clamping, welding or bolting. The packer fixing ring 2-4 is used to cooperate with the bolts 2-5 to achieve positioning and fixing of the liquid-swellable packer 2 in the screen body 1.

[0038] As an optional technical solution, the first flow cross-section formed by the guide slot W1, the second flow cross-section W2 formed between the packer positioning ring 2-3 and the inner wall of the screen body 1, and the third flow cross-section D formed by the axial guide hole 2-7 provided on the packer straightening ring 2-2, all have flow cross-sectional areas that are not less than the predetermined flow cross-sectional requirements.

[0039] Specifically, at the beginning of the completion plan design, the filling flowback flow requirements should be determined in advance, and then the minimum flow cross-section requirements of the flowback channel should be determined in combination with the designed bottom hole pressure difference during filling. When the user is actually completing the well, he should choose products that meet the predetermined flow cross-section requirements, ensuring the first flow cross-section formed by the guide seam W1, the second flow cross-section formed by the gap W2 between the packer positioning ring 2-3 and the inner wall of the screen body 1, and the third flow cross-section formed by the axial guide hole 2-7 set on the packer straightening ring 2-2 (see Figure 1 In the figure mark D, if multiple axial flow guide holes 2-7 are set, the size of the third flow cross-section is the sum of the flow cross-sections of the multiple axial flow guide holes 2-7), and the area of ​​their flow cross-sections is not less than the predetermined flow cross-section requirement.

[0040] As an optional technical solution, the outer side surfaces of the packer straightening ring 2-2, the packer positioning ring 2-3 and / or the baffle 2-6 are provided with chamfers.

[0041] Specifically, when producing and assembling the sacrificial screen tube that can improve the filling efficiency, it is necessary to insert the liquid-expandable seal 2 into the screen tube body 1 from one end of the screen tube body 1. Since the diameter difference between the two is small, in order to facilitate the assembly of the two into one, the angular parts of the circumferential side position assembly of the liquid-expandable seal 2, such as the outer side of the seal straightening ring 2-2, the seal positioning ring 2-3 and the baffle 2-6, can be chamfered, which will be beneficial to the production and assembly process of the sacrificial screen tube that can improve the filling efficiency.

[0042] The above content is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention cannot be considered to be limited to these descriptions. For those skilled in the art of the present invention, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should be considered to fall within the scope of protection of the present invention.

Claims

1. A sacrificial screen tube capable of improving filling efficiency, comprising a screen tube body, characterized in that: The screen body is provided with a liquid expansion packer, wherein: When the liquid-expandable packer is in an initial state, a guide gap exists between the packer and the inner wall of the screen body; After the liquid-expandable packer is lowered into the wellbore, it expands from its initial state to an expanded state upon contact with liquid, thereby sealing the diversion gap between the packer and the inner wall of the screen body.

2. The sacrificial screen capable of improving filling efficiency according to claim 1, characterized in that: The sieve tube body is a tubular structure, with a cylindrical screen provided around the outer wall, and sieve holes provided on the screen; radial guide holes are provided at the position of the outer wall of the sieve tube body covered by the screen.

3. The sacrificial screen capable of improving filling efficiency according to claim 2, characterized in that: The outer wall of the sieve tube body is further provided with a sieve fixing ring, and the sieve is clamped between the sieve fixing rings.

4. The sacrificial screen capable of improving filling efficiency according to claim 1, characterized in that: The liquid-expandable packer includes a carrier and an expansion rubber tube, wherein the carrier is an axial structure and is coaxially arranged inside the screen body; the expansion rubber tube is annularly arranged on the outside of the carrier.

5. The sacrificial screen capable of improving filling efficiency according to claim 4, characterized in that: The liquid-expandable packer further comprises a baffle, which is an annular structure and is arranged on the carrier at both sides of the expansion rubber cylinder to limit the expansion rubber cylinder; the outer diameter of the baffle is consistent with the outer diameter of the expansion rubber cylinder.

6. The sacrificial screen capable of improving filling efficiency according to claim 5, characterized in that: The liquid-expandable packer further comprises a packer straightening ring, and the number of the packer straightening rings is at least two, and the rings are arranged on the carrier at positions on both sides of the baffle; the packer straightening rings are also provided with axial guide holes.

7. The sacrificial screen capable of improving filling efficiency according to claim 6, characterized in that: The liquid-swellable packer further comprises a packer positioning ring, which is arranged on the carrier and has an outer diameter smaller than an inner diameter of the screen body; a radial threaded countersunk hole is provided on the outer circumference of the packer positioning ring.

8. The sacrificial screen capable of improving filling efficiency according to claim 7, characterized in that: A packer fixing ring is also provided on the circumferential outer side of the screen tube body. The packer fixing ring and the screen tube body are provided with radial bolt through holes at positions corresponding to the threaded countersunk holes of the packer fixing ring. Limit bolts are provided in the bolt through holes and the threaded countersunk holes.

9. The sacrificial screen capable of improving filling efficiency according to claim 8, characterized in that: The first flow cross section formed by the guide slit, the second flow cross section formed between the packer positioning ring and the inner wall of the screen tube body, and the third flow cross section formed by the axial guide hole provided on the packer straightening ring, all have flow cross-sectional areas that are not less than the predetermined flow cross-sectional requirements.

10. The sacrificial screen capable of improving filling efficiency according to claim 9, characterized in that: The outer side surfaces of the packer straightening ring, the packer positioning ring and / or the baffle are provided with chamfers.

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