Self-unblocking pre-filling sand control pipe based on elastic instability particle dispersion filling

Abstract

The invention provides a self-unblocking pre-filling sand prevention pipe based on elastic instability particle dispersed filling, the self-unblocking pre-filling sand prevention pipe based on elastic instability particle dispersed filling comprises an outer pipe, an inner pipe and a base pipe, the outer pipe, the inner pipe and the base pipe are sequentially arranged in a sleeved mode from outside to inside in the radial direction of the outer pipe, and the outer pipe and the inner pipe are arranged at intervals to form a filling layer; common ceramsite and at least one type of elastic instability particles are arranged in the filling layer, and the elastic instability particles can deform according to the change of the pressure difference between the inside and the outside of a shaft, so that the local blockage of the filling layer is automatically relieved. According to the self-blockage-removal pre-filling sand control pipe based on elastic instability particle dispersed filling, the elastic instability particles capable of responding to the pressure difference change are introduced, the problem that filling is uneven due to factors such as gravity and well deviation in a traditional pre-filling screen pipe is solved, blocked fine sand can be discharged in time, the self-blockage-removal function is achieved, and the sand control efficiency is improved. And the sand blocking efficiency and stability are improved.

Description

Technical Field

[0001] This invention relates to the field of sand control pipe technology, and in particular to a self-dissolving pre-filled sand control pipe based on elastically unstable particle dispersion filling. Background Technology

[0002] Pre-filled screens, widely used in oil and gas well sand control technology, have many shortcomings. During the filling process, due to factors such as gravity settling, well inclination, and local blockage, the ceramsite is unevenly distributed in the annulus of the screen. Some areas are densely filled, while other areas have gaps or are not filled at all, resulting in a discontinuous filter layer structure and affecting the overall sand control effect.

[0003] Furthermore, the fixed filter layer structure of traditional pre-filled screens cannot adaptively adjust to changes in formation pressure differentials. Under high pressure or pressure fluctuations, fine sand intrusion or filter layer damage can easily occur, leading to early sand production failure. Additionally, once local blockage occurs during use, the screen lacks an effective self-unblocking mechanism, resulting in decreased filter layer performance, severely impacting service life, and increasing well workover frequency and operating costs. Summary of the Invention

[0004] This invention provides a self-dissolving pre-filled sand-proof pipe based on elastically unstable particle dispersion filling, which solves the defects of uneven filling of pre-filled screen pipes, discontinuous filter layer structure, poor anti-clogging ability and lack of dynamic adaptability in the prior art. It realizes the self-adjustment of filter layer density under different pressure difference conditions, automatic release of local blockage, and continuous performance of long-term stable sand-proof function.

[0005] This invention provides a self-dissolving pre-filled sand-proof pipe based on elastically unstable particle dispersion filling, comprising: An outer tube, an inner tube, and a base tube are arranged sequentially from the outside to the inside along the radial direction of the outer tube, and the outer tube and the inner tube are arranged at intervals to form a filling layer; The filling layer contains ordinary ceramic particles and at least one type of elastic unstable particles. The elastic unstable particles can deform according to the pressure difference between the inside and outside of the wellbore, so as to automatically release the local blockage of the filling layer.

[0006] In some embodiments, the elastic unstable particle includes a first elastic unstable particle, which deforms when the pressure difference between the inside and outside of the wellbore is 4 MPa ± Δ.

[0007] In some embodiments, the elastic unstable particle includes a second elastic unstable particle, which deforms when the pressure difference between the inside and outside of the wellbore is 6 MPa ± Δ.

[0008] In some embodiments, the elastic unstable particle includes a third elastic unstable particle, which deforms when the pressure difference between the inside and outside of the wellbore is 8 MPa ± Δ.

[0009] In some embodiments, the elastic unstable particle includes a shell and an inner cavity, wherein the dimension of the shell in the radial direction of the elastic unstable particle is the wall thickness of the elastic unstable particle, the wall thickness of the first elastic unstable particle is a1, the wall thickness of the second elastic unstable particle is a2, and the wall thickness of the third elastic unstable particle is a3, wherein a1 < a2 < a3.

[0010] In some embodiments, the volume percentage of the elastically unstable particles in the filling layer is less than 10%.

[0011] In some embodiments, when the median particle size of the stratum sand is less than 150 μm, the filling rate of the elastically unstable particles in the filling layer is <8%.

[0012] In some embodiments, when the median particle size of the stratum sand is 150-250 μm, the filling rate of the elastically unstable particles in the filling layer is 5%-6%.

[0013] In some embodiments, when the pressure difference between the inside and outside of the wellbore is 4MPa±Δ, only the ordinary ceramsite and the first elastically unstable particles are filled. When the pressure difference between the inside and outside of the wellbore is 6MPa±△, only the ordinary ceramic particles and the second elastic unstable particles are filled.

[0014] In some embodiments, when the pressure difference between the inside and outside of the wellbore is 8MPa±Δ, the ordinary ceramic particles, the first elastically unstable particles, the second elastically unstable particles, and the third elastically unstable particles are used for filling.

[0015] The self-dissolving pre-filled sand-control pipe based on the dispersion filling of elastically unstable particles in this invention solves the problem of uneven filling caused by gravity, well inclination and other factors in traditional pre-filled screen pipes by introducing elastically unstable particles that can respond to pressure difference changes. It realizes the adaptive control of the filter layer and improves the sand-blocking efficiency and long-term stability. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is a half-section structural diagram of the self-dissolving pre-filled sand-proof pipe based on elastically unstable particle dispersion filling provided by the present invention.

[0018] Figure 2 This is a schematic diagram of the self-unblocking pre-filling sand-proof pipe particle filling based on the elastically unstable particle dispersion filling provided by the present invention, taking the mixing and filling of the first elastically unstable particles and ordinary ceramic particles as an example.

[0019] Figure 3 This is a schematic diagram of three types of elastically unstable particles provided by the present invention.

[0020] Figure 4 This is a schematic diagram of the compression structure of the first, second, and third elastically unstable particles.

[0021] Figure label: 1. Outer tube; 2. Inner tube; 3. Base tube; 4. Ordinary ceramsite; 5. First elastically unstable particle; 6. Second elastically unstable particle; 7. Third elastically unstable particle. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0023] The self-unblocking pre-filled sand-proof pipe based on elastically unstable particle dispersion filling in this embodiment of the invention includes an outer pipe 1, an inner pipe 2 and a base pipe 3. The outer pipe 1, the inner pipe 2 and the base pipe 3 are arranged sequentially from the outside to the inside along the radial direction of the outer pipe 1. The outer pipe 1 and the inner pipe 2 are arranged at intervals to form a filling layer.

[0024] The filling layer contains ordinary ceramic particles 4 and at least one type of elastic unstable particles. The elastic unstable particles can deform according to the pressure difference between the inside and outside of the wellbore, so as to realize the automatic release of local blockage of the filling layer.

[0025] The outer tube 1, inner tube 2, and base tube 3 are arranged sequentially from the outside to the inside along the radial direction of the outer tube 1. An annular space, called a filling layer, is formed between the outer tube 1 and the inner tube 2 at intervals. This filling layer is filled with ordinary ceramic particles 4 and at least one type of elastically unstable particles.

[0026] Elastic buckling particles, also known as elastic buckling particles, can deform in response to changes in the pressure difference between the inside and outside of the wellbore. When the pressure difference increases, the elastic buckling particles are compressed, their volume decreases, and the space within the filling layer increases. This allows for timely drainage of fine sand, reducing the risk of blockage in the filling layer. A reasonable filling ratio of elastic buckling particles can also ensure that the filling layer does not reduce its sand-control accuracy while discharging fine sand, thereby improving the sand-control performance of the filling layer. This dynamic adjustment capability allows the sand control pipe to adapt to complex and variable formation conditions, enhancing its sand-control performance.

[0027] Moreover, different types of elastically unstable particles can deform under different pressure differentials due to differences in wall thickness and materials (such as metal microspheres and rubber particles).

[0028] This invention provides a self-dissolving pre-filled sand control pipe based on dispersed filling of elastically unstable particles. By introducing elastically unstable particles with compression and rebound capabilities into the filling layer, it effectively solves the problems of uneven filter layer distribution, fixed structure, and poor anti-clogging performance in traditional pre-filled screen pipes. This structure can dynamically adjust the filter layer density when the downhole pressure differential changes. Under high pressure differential conditions, it achieves self-dissolving by reducing the volume of the elastically unstable particles, while ensuring stable sand-blocking accuracy and improving the sand-blocking capacity of the self-dissolving pre-filled sand control pipe based on dispersed filling of elastically unstable particles.

[0029] Compared with existing technologies, this solution has the following significant effects: it improves the uniformity and continuity of the filling layer; it enhances the adaptability of the self-unblocking pre-filled sand control pipe based on elastically unstable particle dispersed filling to formation pressure fluctuations; it extends the service life of the self-unblocking pre-filled sand control pipe based on elastically unstable particle dispersed filling; and it reduces the frequency of well workovers and maintenance costs caused by blockages.

[0030] Therefore, the self-dissolving pre-filled sand-proof pipe based on elastically unstable particle dispersion filling in the embodiments of the present invention has the advantages of good filling uniformity, high filter layer stability, strong self-dissolving ability, and strong adaptability to complex geological conditions.

[0031] In some embodiments, the elastically unstable particle includes a first elastically unstable particle 5, which deforms when the pressure difference between the inside and outside of the wellbore is 4 MPa ± Δ. Here, Δ is 0.3 MPa-0.5 MPa.

[0032] The first elastically unstable particle 5 begins to deform when the pressure difference between the inside and outside of the wellbore reaches 4 MPa ± Δ. This design makes it suitable for medium-low pressure differential reservoir environments, automatically compacting the filter layer under high pressure differential in the early stages of production to prevent fine sand from entering the wellbore.

[0033] The self-unblocking pre-filled sand-preventing pipe based on the elastically unstable particle dispersion filling of this invention has a reasonable set response pressure for the first elastically unstable particle 5, which can effectively increase the sand-blocking density in the early stage of production, while avoiding ineffective deformation caused by premature activation, thus improving the adaptability of the sand-preventing pipe to medium and low production pressure differential reservoirs.

[0034] In some embodiments, the elastically unstable particle includes a second elastically unstable particle 6, which deforms when the pressure difference between the inside and outside of the wellbore is 6 MPa ± Δ. Here, Δ is 0.3 MPa-0.5 MPa.

[0035] The second elastic unstable particle 6 deforms when the pressure difference between the inside and outside of the wellbore is 6 MPa ± Δ. Compared with the first elastic unstable particle 5, the second elastic unstable particle 6 has a higher trigger pressure threshold and is suitable for reservoir environments with higher pressure differentials.

[0036] The self-dissolving pre-filled sand-proof pipe based on the dispersion filling of elastically unstable particles in this embodiment of the invention expands the application range of the sand-proof pipe by adding the second elastically unstable particle 6, enabling it to maintain good filter layer density and anti-clogging ability under high production pressure differential conditions.

[0037] In some embodiments, the elastically unstable particle includes a third elastically unstable particle 7, which deforms when the pressure difference between the inside and outside of the wellbore is 8 MPa ± Δ. Here, Δ is 0.3 MPa-0.5 MPa.

[0038] The third elastically unstable particle 7 deforms when the pressure difference between the inside and outside of the wellbore is 8 MPa ± Δ. Its response pressure difference is higher than the previous two, making it suitable for complex conditions such as extreme high pressure differences or deep reservoirs.

[0039] The self-dissolving pre-filled sand-proof pipe based on the dispersion filling of elastically unstable particles in this embodiment of the invention enhances the stability and adaptability of the sand-proof pipe under high pressure differential environment by introducing the third elastically unstable particle 7, ensuring that the filter layer structure can still maintain integrity under strong fluid impact and preventing early sand discharge failure.

[0040] In some embodiments, the elastic unstable particle includes a shell and an inner cavity. The size of the shell in the radial direction of the elastic unstable particle is equal to the wall thickness of the elastic unstable particle. The wall thickness of the first elastic unstable particle 5 is a1, the wall thickness of the second elastic unstable particle 6 is a2, and the wall thickness of the third elastic unstable particle 7 is a3, wherein a1 < a2 < a3.

[0041] The greater the wall thickness, the more difficult it is to compress the elastically unstable particles, thus requiring a higher trigger differential pressure. This structural design allows different types of elastically unstable particles to respond to different downhole pressure conditions as needed.

[0042] The self-dissolving pre-filled sand-proof pipe based on the dispersed filling of elastically unstable particles in this invention achieves precise control of the response pressure difference of different types of elastically unstable particles by controlling the wall thickness and material differences of the elastically unstable particles, thereby realizing a graded response mechanism, enhancing the dynamic control capability of the filter layer, and realizing the self-dissolving function inside the self-dissolving pre-filled sand-proof pipe based on the dispersed filling of elastically unstable particles.

[0043] In some embodiments, the volume percentage of elastically unstable particles in the filling layer is less than 10%. The total volume percentage of elastically unstable particles is less than 10%. This ratio ensures that the filter layer has sufficient adjustment capability without affecting the overall structural strength and sand-blocking performance due to excessive elastically unstable particles.

[0044] The self-dissolving pre-filled sand-proof pipe based on the dispersed filling of elastically unstable particles in this invention has a reasonable proportion of elastically unstable particles, which ensures the uniformity and self-adaptive ability of the filter layer while taking into account structural strength and economy, thus improving the overall practicality of the sand-proof pipe.

[0045] The filling rate of elastically unstable particles is related to the median particle size of the formation sand. As the median particle size increases, the filling rate decreases. This can avoid the reduction in sand-blocking accuracy of the self-unblocking pre-filled sand-control pipe based on the dispersed filling of elastically unstable particles due to excessive elastically unstable particles.

[0046] In some embodiments, when the median particle size of the stratum sand is less than 150 μm, the filling rate of elastically unstable particles in the filling layer is <8%.

[0047] In some embodiments, when the median particle size of the stratum sand is 150-250 μm, the filling rate of elastically unstable particles in the filling layer is 5%-6%.

[0048] In some embodiments, when the pressure difference between the inside and outside of the wellbore is 4 MPa ± Δ, only ordinary ceramic particles and first elastically unstable particles are used for filling. This is because in such reservoirs, the pressure difference is low, and there is no need to use elastically unstable particles with high response pressure; effective self-unblocking and filter layer adjustment functions can be achieved solely by the first elastically unstable particles 5.

[0049] The self-dissolving pre-filled sand-preventing pipe based on elastically unstable particle dispersion filling in this embodiment of the invention is optimized for low-pressure-difference reservoirs, saving material costs while achieving good sand-prevention effects.

[0050] When the pressure difference between the inside and outside of the wellbore is 6MPa±△, only ordinary ceramic particles 4 and second elastically unstable particles 6 are filled.

[0051] This allows for the activation of different types of elastically unstable particles at different pressure differential stages, enabling phased adjustment of the filter layer.

[0052] The self-dissolving pre-filled sand-proof pipe based on the dispersed filling of elastically unstable particles in this invention uses two types of elastically unstable particles in combination, which enables the self-dissolving pre-filled sand-proof pipe based on the dispersed filling of elastically unstable particles to have stronger dynamic adaptability in a medium pressure difference range, thereby improving sand blocking efficiency and self-dissolving performance.

[0053] In some embodiments, when the pressure difference between the inside and outside of the wellbore is 8MPa±Δ, ordinary ceramic particles 4, first elastically unstable particles 5, second elastically unstable particles 6 and third elastically unstable particles 7 are used for filling.

[0054] This configuration and the volume ratio of the elastically unstable particles ensure that the filter layer still has good sand-blocking accuracy and structural stability under high pressure differential conditions, while also having a strong self-cleaning ability.

[0055] The self-dissolving pre-filled sand control pipe based on the dispersed filling of elastically unstable particles in this invention significantly enhances the reliability of the sand control pipe in high-pressure differential reservoirs by using an appropriate volume ratio of elastically unstable particles with high strength response, extends its service life, stabilizes the sand-blocking accuracy of the self-dissolving pre-filled sand control pipe based on the dispersed filling of elastically unstable particles, reduces the clogging risk of the self-dissolving pre-filled sand control pipe based on the dispersed filling of elastically unstable particles, and reduces the maintenance frequency.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A self-dissolving pre-filled sand-proof pipe based on elastically unstable particle dispersion filling, characterized in that, include: The outer tube (1), the inner tube (2) and the base tube (3) are arranged sequentially from the outside to the inside along the radial direction of the outer tube (1), and the outer tube (1) and the inner tube (2) are arranged at intervals to form a filling layer; The filling layer contains ordinary ceramic particles (4) and at least one type of elastic unstable particles. The elastic unstable particles can deform according to the pressure difference between the inside and outside of the wellbore, so as to realize the automatic release of local blockage of the filling layer.

2. The self-dissolving pre-filled sand-proof pipe based on elastically unstable particle dispersion filling according to claim 1, characterized in that, The elastic unstable particle includes a first elastic unstable particle (5), which deforms when the pressure difference between the inside and outside of the wellbore is 4MPa±Δ.

3. The self-dissolving pre-filled sand-proof pipe based on elastically unstable particle dispersion filling according to claim 2, characterized in that, The elastic unstable particle includes a second elastic unstable particle (6), which deforms when the pressure difference between the inside and outside of the wellbore is 6 MPa ± Δ.

4. The self-dissolving pre-filled sand-proof pipe based on elastically unstable particle dispersion filling according to claim 3, characterized in that, The elastic unstable particle includes a third elastic unstable particle (7), which deforms when the pressure difference between the inside and outside of the wellbore is 8MPa±Δ.

5. The self-dissolving pre-filled sand-proof pipe based on elastically unstable particle dispersion filling according to claim 4, characterized in that, The elastic unstable particle includes a shell and an inner cavity. The size of the shell in the radial direction of the elastic unstable particle is the wall thickness of the elastic unstable particle. The wall thickness of the first elastic unstable particle (5) is a1, the wall thickness of the second elastic unstable particle (6) is a2, and the wall thickness of the third elastic unstable particle (7) is a3, wherein a1 < a2 < a3.

6. The self-dissolving pre-filled sand-proof pipe based on elastically unstable particle dispersion filling according to claim 1, characterized in that, In the filling layer, the volume percentage of the elastically unstable particles is less than 10%.

7. The self-dissolving pre-filled sand-proof pipe based on elastically unstable particle dispersion filling according to claim 1, characterized in that, When the median particle size of the stratum sand is less than 150 μm, the filling rate of the elastically unstable particles in the filling layer is <8%.

8. The self-dissolving pre-filled sand-proof pipe based on elastically unstable particle dispersion filling according to claim 1, characterized in that, When the median particle size of the stratum sand is between 150 and 250 μm, the filling rate of the elastically unstable particles in the filling layer is 5% to 6%.

9. The self-dissolving pre-filled sand-proof pipe based on elastically unstable particle dispersion filling according to claim 4, characterized in that, When the pressure difference between the inside and outside of the wellbore is 4MPa±△, only the ordinary ceramic particles and the first elastic unstable particles are filled. When the pressure difference between the inside and outside of the wellbore is 6MPa±△, only the ordinary ceramic particles and the second elastic unstable particles are filled.

10. The self-dissolving pre-filled sand-proof pipe based on elastically unstable particle dispersion filling according to claim 9, characterized in that, When the pressure difference between the inside and outside of the wellbore is 8MPa±Δ, the wellbore is filled with the ordinary ceramic particles, the first elastically unstable particles, the second elastically unstable particles, and the third elastically unstable particles.

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