Separated layer water injection tubular column structure for oil field

Abstract

The utility model provides an oil field separate layer water injection tubular column structure which comprises an oil well casing pipe, an oil pipe, at least one packing unit and a plurality of water distributors, the packing unit and the water distributors are installed on the oil pipe, the packing unit divides a tubular column into a plurality of water injection units, and the water distributors are arranged in the water injection units in a one-to-one correspondence mode. The packer unit comprises a first packer and a second packer, the first packer is located above the second packer, and a buffer area is formed between the first packer and the second packer. The layered water injection tubular column structure for the oil field has the advantage that the packing function is not easy to lose efficacy during high-pressure water injection.

Description

Technical Field

[0001] This utility model relates to the field of petroleum extraction technology, specifically to a layered water injection pipe string structure for oil fields. Background Technology

[0002] Layered water injection tubing is a key downhole tool assembly used in oilfield development to achieve layered water injection. Its core purpose is to address differences in water absorption between oil layers, optimize water injection effects, and improve oil recovery. Layered water injection tubing mainly consists of tubing, packers, distributors, well-washing valves, and plugs. Packers separate oil layers with different permeability zones to prevent fluid cross-contamination during water injection. Distributors are installed in each layer to regulate the water injection volume, achieving quantitative layered water injection.

[0003] Existing packers are equipped with support slips for clamping the inner wall of the well casing and rubber sleeves for sealing. Some rubber sleeves expand hydraulically or mechanically to seal the annular space between the tubing and casing, while others are compressed and deformed by applying pressure when the tubing string is lifted or rotated to achieve a seal. In actual use, when the injection pressure is high, the entire tubing will experience significant swaying due to the upward pressure. The support performance of the support slips and the sealing performance of the rubber sleeves can easily be compromised. In severe cases, lower-layer water can seep through the gap between the casing and the rubber sleeve, causing the packer to fail. This necessitates retrieval for repair, which is a very troublesome process.

[0004] In order to solve the above problems, people have been seeking an ideal technological solution. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing an oilfield stratified water injection tubing structure that is less prone to sealing failure during high-pressure water injection.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is: an oilfield layered water injection string structure, including an oil well casing, an oil tubing, at least one packer unit installed on the oil tubing, and multiple water distributors. The packer unit divides the string into multiple water injection units, and the multiple water distributors are arranged one-to-one in the multiple water injection units. The packer unit includes a first packer and a second packer. The first packer is located above the second packer, and a buffer area is formed between the first packer and the second packer.

[0007] Beneficial effect: When the water injection pressure is high, the second packer will be subjected to the upward pressure first, which greatly reduces the pressure on the first packer, thus playing a protective role and preventing the packing function from failing.

[0008] Based on the above, the first packer is a conventional packer; the outer wall of the rubber sleeve of the second packer is provided with concave and convex surfaces. When the rubber sleeve expands or is compressed and deformed to contact the inner wall of the oil well casing, a tiny gap is formed between the concave and convex surfaces and the inner wall of the oil well casing, allowing liquid to flow through.

[0009] Beneficial effects: The uneven surface weakens the sealing function of the second packer. When pressurized water rushes up, a small amount of water will pass through the tiny gaps and enter the buffer area, which also reduces the pressure on the second packer and makes the second packer less prone to damage.

[0010] Based on the above, the concave and convex surfaces are multiple spherical protrusions provided on the outer wall of the rubber tube, and the multiple spherical protrusions are evenly and staggeredly arranged.

[0011] Beneficial effect: The regular layout of the spherical protrusions makes them easier to process.

[0012] Based on the above, the length of the buffer zone is 5-6m.

[0013] Beneficial effects: Compared with the first packer and the second packer, it is easier to run into the well (the straightness of the well wall in some parts of the oil well is not high, and the two packers are easy to get stuck if they are too close), and the buffer space is also moderate.

[0014] Based on the above, both the rubber sleeve of the first packer and the rubber sleeve of the second packer are made of cord rubber sleeve.

[0015] Beneficial effects: More suitable for oilfield formations with low permeability and poor water absorption. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the oilfield layered water injection pipe string structure in Example 1.

[0017] Figure 2 This is a schematic diagram of the structure of the rubber tube in the second packer in Example 2.

[0018] In the diagram: 1. Oil well casing; 2. Tubing; 3. Water distributor; 4. Water injection unit; 5. Wash inlet valve; 6. Plug; 7. First packer; 8. Second packer; 9. Buffer zone; 10. Rubber sleeve; 11. Spherical protrusion. Detailed Implementation

[0019] The technical solution of this utility model will be further described in detail below through specific embodiments. Example 1

[0020] like Figure 1As shown, an oilfield layered water injection string structure includes an oil well casing 1, an oil tubing 2, at least one packer unit installed on the oil tubing 2, and multiple water distributors 3. The packer unit divides the string into multiple water injection units 4, and the multiple water distributors 3 are arranged one-to-one in the multiple water injection units 4. The tail end of the oil tubing 2 is also provided with a flushing valve 5 and a plug 6. This part belongs to the layered water injection string structure commonly used in the prior art.

[0021] To prevent the packer function from failing, the packer unit includes a first packer 7 and a second packer 8. The first packer 7 is located above the second packer 8, and a buffer area 9 is formed between the first packer 7 and the second packer 8. The length of the buffer area 9 is specifically 5-6m. Compared with the first packer and the second packer being installed adjacent to each other, it is not only convenient to run into the well (the straightness of the well wall in some oil wells is not high, and the two packers are easy to get stuck if they are too close), but the buffer space is also moderate. It will not reduce the buffering effect due to the distance being too close, nor will it leave a long section of the tubing without protective measures due to the distance being too far.

[0022] Working principle:

[0023] The first packer 7 and the second packer 8 are installed one above the other, with their rubber sleeves 10 in contact with the inner wall of the well casing 1. When the water injection pressure in the lower layer is high, the second packer 8 is preferentially subjected to the upward pressure and is preferentially damaged. In this way, the pressure on the first packer 7 is greatly reduced, which plays a protective role and prevents the packing function from failing. Example 2

[0024] like Figure 2 As shown, the difference between this embodiment and embodiment 1 is that the first packer 7 adopts a conventional packer; the outer wall of the rubber tube 10 of the second packer 8 is provided with a concave-convex surface, which is a plurality of spherical protrusions 11 provided on the outer wall of the rubber tube 10, and the plurality of spherical protrusions 11 are evenly and staggeredly arranged.

[0025] In use, the uneven surface weakens the sealing function of the second packer 8. When the rubber sleeve 10 expands or is compressed and deformed to contact the inner wall of the oil well casing 1, a tiny gap is formed between the uneven surface and the inner wall of the oil well casing 1, allowing liquid to flow through. When pressurized water rushes up, a small amount of water will pass through the tiny gap and enter the buffer area 9, which also reduces the pressure on the second packer 8. The pressure change on the first packer 7 is also very small, which makes the second packer 8 less prone to damage. Example 3

[0026] The difference between this embodiment and other embodiments is that the rubber sleeve 10 of the first packer 7 and the rubber sleeve 10 of the second packer 8 are both made of cord rubber sleeves. This is to be suitable for oilfield formations with low permeability and poor water absorption capacity, such as the Wenbei Oilfield where the applicant operates. Previously, steel wire rubber sleeves were used. Due to the small pressure difference of the water nozzle, some water injection well packers could not be set or lost their seal, making it difficult to achieve effective stratified water injection. After using cord rubber sleeves, normal setting was achieved, ensuring effective stratified water injection.

[0027] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and not to limit it; although the utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of this utility model or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solution of this utility model, and all such modifications and substitutions should be covered within the scope of the technical solution claimed by this utility model.

Claims

1. A layered water injection string structure for oilfields, comprising well casing, tubing, at least one packer unit installed on the tubing, and multiple water distributors, wherein the packer unit divides the string into multiple water injection units, and the multiple water distributors are correspondingly arranged in the multiple water injection units, characterized in that: The packer unit includes a first packer and a second packer, with the first packer located above the second packer, and a buffer area formed between the first packer and the second packer.

2. The oilfield layered water injection tubing structure according to claim 1, characterized in that: The first packer is a conventional packer; the outer wall of the rubber sleeve of the second packer is provided with concave and convex surfaces. When the rubber sleeve expands or is compressed and deformed to contact the inner wall of the oil well casing, a tiny gap is formed between the concave and convex surfaces and the inner wall of the oil well casing, allowing liquid to flow through.

3. The oilfield layered water injection tubing structure according to claim 2, characterized in that: The concave and convex surfaces are multiple spherical protrusions provided on the outer wall of the rubber tube, and the multiple spherical protrusions are evenly and staggeredly arranged.

4. The oilfield layered water injection string structure according to any one of claims 1-3, characterized in that: The length of the buffer zone is 5-6m.

5. The oilfield layered water injection string structure according to claim 4, characterized in that: Both the rubber sleeve of the first packer and the rubber sleeve of the second packer are made of cord rubber sleeve.

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