Screen mesh assembly suitable for fine silt reservoir and capable of giving consideration to sand prevention and blocking prevention and application method of screen mesh assembly
By designing a screen assembly with multi-stage aperture variation, the problem of simultaneously preventing sand and clogging in fine sand reservoirs was solved, achieving a unified approach to sand prevention and clogging and extending the duration of sand prevention.
Patent Information
- Application Number
- CN202511629497.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-07
- Publication Date
- 2025-12-30
AI Technical Summary
Existing screens are unable to simultaneously achieve both sand control and anti-clogging effects in fine sand reservoirs, leading to unstable mining operations.
Design a screen assembly including an anti-clogging optimization layer, a basic sand control layer, and a sand control optimization layer, with the pore size changing from large to small. The anti-clogging optimization layer faces the reservoir, and the sand control optimization layer faces the wellbore. The multi-stage filtration achieves stratified interception of particles.
It achieves the unity of sand prevention and clogging prevention, reduces the accumulation of particles on the clogging prevention layer, extends the duration of effective sand prevention, and reduces sand output and clogging risk.
Smart Images
Figure CN121229036A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of oil and gas exploitation engineering, and particularly relates to a screen assembly suitable for fine silt reservoir and capable of preventing sand and plugging and an application method thereof. BACKGROUND
[0002] Fine silt reservoirs are widely present in oil and gas reservoirs and natural gas hydrate reservoirs. Due to the fine particles and weak cementation, serious sand production problems generally exist in the exploitation process, resulting in wellbore sand settling, production equipment wear and even production stoppage accidents. The existing mechanical sand control screen is mainly in the form of square mesh screen pipe, wire-wound screen pipe and sintered screen pipe. Under the condition of fine silt reservoir, the screen in the above-mentioned structural form generally has the following problems: reducing the filter aperture can improve the sand control effect, but can aggravate the plugging, and the plugging is mainly manifested as the rapid formation of external mud cake, resulting in a decrease in permeability. Therefore, the application of the current screen to the fine silt reservoir is opposite to the sand control effect and the plugging effect, and the two effects are difficult to be considered together, which can lead to unstable exploitation. SUMMARY
[0003] In view of the above problems, the present application aims to provide a screen assembly suitable for fine silt reservoir and capable of preventing sand and plugging and an application method thereof, so as to solve the problem that the application of the current screen to the fine silt reservoir is opposite to the sand control effect and the plugging effect, and the two effects are difficult to be considered together.
[0004] To achieve the above-mentioned purpose, the present application adopts the following technical solutions: In a first aspect, the present application discloses a screen assembly suitable for fine silt reservoir and capable of preventing sand and plugging, characterized in that the screen assembly comprises a plurality of screen units, the plurality of screen units are stacked together from top to bottom, and the aperture of the plurality of screen units decreases from the side facing the fine silt reservoir to be developed to the side facing the wellbore.
[0005] Specifically, the screen assembly comprises a plugging prevention optimization layer, a basic sand control layer and a sand control optimization layer, and the basic sand control layer is arranged between the plugging prevention optimization layer and the sand control optimization layer. The plugging prevention optimization layer is arranged to face the fine silt reservoir to be developed, the sand control optimization layer is arranged to face the wellbore, and the apertures of the plugging prevention optimization layer, the basic sand control layer and the sand control optimization layer decrease in turn.
[0006] Specifically, the fine silt reservoir comprises large-diameter particles, small-diameter particles and fine powder particles, The plugging prevention optimization layer is arranged to prevent the large-diameter particles from passing through and allow the small-diameter particles and the fine powder particles to pass through; The basic sand control layer is arranged to allow the fine powder particles and part of the small-diameter particles to pass through, and prevent the remaining small-diameter particles from passing through; The sand prevention optimization layer is used for allowing only fine powder particles to pass through, and trapping a small part of small particle size particles.
[0007] In a second aspect, the application further discloses an application method of the screen assembly suitable for fine powder sand reservoirs and capable of preventing sand and plugging, and the method comprises the following steps: Step A: disposing the screen assembly in the fine powder sand reservoir, so that the plugging prevention optimization layer faces the fine powder sand reservoir to be developed, and the sand prevention optimization layer faces the wellbore; Step B: the large particle size particles, the small particle size particles and the fine powder particles mixed in the fine powder sand reservoir pass through the screen assembly along with fluid movement; Step C: along with the continuation of step B, the large particle size particles trapped by the plugging prevention optimization layer, the most small particle size particles trapped by the base sand prevention layer and the small part of small particle size particles trapped by the sand prevention optimization layer present a change in particle size from large to small in space, so that a spatial gap with a gradually decreasing pore size from outside to inside is formed in space, which helps to reduce the accumulation of particles in the fine powder sand reservoir on the plugging prevention optimization layer, increases the accommodation capacity of particles in the fine powder sand reservoir, and thus prolongs the duration of the effective sand prevention state.
[0008] In the step B, the following specific steps are included: Step B1: the large particle size particles are trapped by the plugging prevention optimization layer, and the small particle size particles and the fine powder particles pass through the pore size of the plugging prevention optimization layer; Step B2: the fine powder particles and part of the small particle size particles pass through the pore size of the base sand prevention layer, and the remaining part of the small particle size particles are trapped by the base sand prevention layer; Step B3: only the fine powder particles pass through the sand prevention optimization layer, and a small part of the small particle size particles are trapped by the sand prevention optimization layer.
[0009] Compared with the prior art, the application has the following beneficial effects: (1) The application discloses a screen assembly suitable for fine powder sand reservoirs and capable of preventing sand and plugging, which comprises a plugging prevention optimization layer, a base sand prevention layer and a sand prevention optimization layer, and the base sand prevention layer is arranged between the plugging prevention optimization layer and the sand prevention optimization layer; wherein the plugging prevention optimization layer faces the fine powder sand reservoir to be developed, the sand prevention optimization layer faces the wellbore, and the pore sizes of the plugging prevention optimization layer, the base sand prevention layer and the sand prevention optimization layer change from large to small in sequence. The fine powder sand reservoir includes large particle size particles, small particle size particles and fine powder particles, so when the screen assembly is applied to the fine powder sand reservoir, the plugging prevention optimization layer does not allow the large particle size particles to pass through and allows the small particle size particles and the fine powder particles to pass through; the base sand prevention layer allows the fine powder particles and part of the small particle size particles to pass through, and does not allow the remaining part of the small particle size particles to pass through; and the sand prevention optimization layer only allows the fine powder particles to pass through, and traps a small part of the small particle size particles, so that the sand prevention effect and the plugging prevention effect are unified, and the problem that sand prevention and plugging prevention are difficult to be considered together is solved.
[0010] (II) This invention discloses an application method for a screen assembly suitable for fine sand reservoirs that can simultaneously prevent sand and blockage, comprising: Step A: Set the above-mentioned screen assembly in the fine sand reservoir, so that the anti-blocking optimization layer faces the fine sand reservoir to be developed, and the sand control optimization layer faces the wellbore. Step B: Large-diameter particles, small-diameter particles, and fine powder particles embedded in the fine sand reservoir pass through the screen assembly with the fluid movement, including the following specific steps: Step B1: Large-diameter particles are trapped by the anti-clogging optimization layer, while small-diameter particles and fine powder particles pass through the pores of the anti-clogging optimization layer; Step B2: Fine powder particles and some small-diameter particles pass through the pores of the basic sand-proof layer, while the remaining small-diameter particles are trapped by the basic sand-proof layer. Step B3: Only fine powder particles pass through the sand-proof optimization layer, and a small portion of small-diameter particles are retained by the sand-proof optimization layer; Step C: As step B continues, the large-diameter particles trapped by the anti-blocking optimization layer, most of the small-diameter particles trapped by the basic sand control layer, and a small portion of the small-diameter particles trapped by the sand control optimization layer exhibit a spatial variation in particle size from large to small. This creates spatial gaps with pore sizes gradually decreasing from the outside to the inside, which helps reduce the accumulation of particles in the fine silt reservoir on the anti-blocking optimization layer, increases the particle holding capacity in the fine silt reservoir, and thus extends the duration of the effective sand control state.
[0011] This application method shows that large-diameter particles, small-diameter particles, and fine powder particles mixed in the fine sand reservoir pass through the multi-stage filtration of the screen assembly as the fluid moves. The stratification and interception of fine sand of different particle sizes reduces the coordination number of the particle distribution and the local particle density, thereby achieving a balance between sand prevention and blockage prevention. Attached Figure Description
[0012] Figure 1 This is a three-dimensional structural schematic diagram of a screen assembly provided in Embodiment 1 of the present invention, which is suitable for fine sand reservoirs and can simultaneously prevent sand and blockage. Figure 2 yes Figure 1 A schematic diagram of the cross-section after AA-direction sectioning; Figure 3 This is provided in Embodiment 2 of the present invention. Figure 1 A schematic diagram of the application of the screen assembly in fine silt reservoirs.
[0013] Explanation of reference numerals in the attached diagram: 1-Anti-clogging optimization layer, 2-Basic sand-proof layer, 3-Sand-proof optimization layer. Detailed Implementation
[0014] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the invention and to fully convey the scope of the invention to those skilled in the art.
[0015] Example 1: A screen assembly suitable for fine sand reservoirs that can simultaneously prevent sand and blockage. Embodiment 1 of the present invention provides a screen assembly suitable for fine sand reservoirs that can both prevent sand and blockage. Its structure is described in detail below with reference to the accompanying drawings.
[0016] The screen assembly, which is suitable for fine silt reservoirs and can both prevent sand and blockage, includes several screen units stacked together from top to bottom, and the aperture of the screen units gradually decreases from the side facing the fine silt reservoir to the side facing the wellbore.
[0017] Specifically, the screen assembly suitable for fine silt reservoirs and capable of both sand control and clogging prevention includes: Anti-blocking optimization layer 1, Basic sand control layer 2, Sand control optimization layer 3, The anti-clogging optimization layer 1 and the sand-control optimization layer 3 are disposed on both sides of the basic sand-control layer 2, that is, the basic sand-control layer 2 is sandwiched between the anti-clogging optimization layer 1 and the sand-control optimization layer 3. Figure 1 and Figure 2 As shown.
[0018] The anti-blocking optimization layer 1 is directed toward the fine sand reservoir to be developed, and the sand control optimization layer 3 is directed toward the wellbore. The pore sizes of the anti-blocking optimization layer 1, the basic sand control layer 2, and the sand control optimization layer 3 change sequentially from large to small.
[0019] Specifically, fine silt reservoirs include large-diameter particles, small-diameter particles, and fine silt particles. The anti-clogging optimization layer 1 is used to prevent large-diameter particles from passing through (while blocking large-diameter particles) and allows small-diameter particles and fine powder particles to pass through. The basic sand-proof layer 2 is used to allow fine powder particles and some small-diameter particles to pass through, but not to allow the remaining small-diameter particles to pass through; The sand-proof optimization layer 3 is used to allow only fine powder particles to pass through, while retaining a small portion of small-diameter particles.
[0020] Specifically, the anti-blocking optimization layer 1, the basic sand-proof layer 2, and the sand-proof optimization layer 3 are all screens inside independent sand-proof screen tubes.
[0021] The filter pore size of these screens decreases progressively in the direction of fluid flow, and the thickness of each screen layer can be the same or gradient.
[0022] The apparent precision of these screens is the same as that of traditional sand control screens, such as the average value of the total opening area of the mesh / slit, i.e. the average flow area, but the thickness of the external mud cake accumulation layer is significantly reduced.
[0023] Example 2: Application method of a screen assembly suitable for fine sand reservoirs that can simultaneously prevent sand and blockage. Embodiment 2 of the present invention provides an application method for a screen assembly suitable for fine silt reservoirs that can simultaneously prevent sand and blockage. It employs a screen assembly suitable for fine silt reservoirs that can simultaneously prevent sand and blockage, as described in Embodiment 1. (Refer to...) Figure 3 The method includes the following steps: Step A: Set the screen assembly of Example 1 in the fine sand reservoir, with the anti-blocking optimization layer 1 facing the fine sand reservoir to be developed, and the sand control optimization layer 3 facing the wellbore; Step B: Large-diameter particles, small-diameter particles, and fine powder particles embedded in the fine sand reservoir pass through the screen assembly with the fluid movement, including the following specific steps: Step B1: Large-diameter particles are trapped by the anti-clogging optimization layer 1, while small-diameter particles and fine powder particles pass through the pores of the anti-clogging optimization layer 1; Step B2: Fine powder particles and some small-diameter particles pass through the pores of the basic sand-proof layer 2, while the remaining small-diameter particles are trapped by the basic sand-proof layer 2. Step B3: Only fine powder particles pass through the sand-proof optimization layer 3, and a small portion of small-diameter particles are trapped by the sand-proof optimization layer 3.
[0024] Step C: As step B continues, the large-diameter particles intercepted by the anti-blocking optimization layer 1, most of the small-diameter particles intercepted by the basic sand control layer 2, and a small portion of the small-diameter particles intercepted by the sand control optimization layer 3 exhibit a spatial variation in particle size from large to small. This creates spatial gaps where the pore size gradually decreases from the outside to the inside, which helps reduce the accumulation of particles in the fine silt reservoir on the anti-blocking optimization layer 1, increases the particle holding capacity in the fine silt reservoir, and thus extends the duration of the effective sand control state.
[0025] This invention employs a four-way coupling scheme of Discrete Element Method (DEM) and Computational Fluid Dynamics (CFD) to numerically simulate the sand-blocking effect of a gradient structure multilayer sand-control screen. Fluid enters a fine silt reservoir, passes through it, and then enters the screen assembly. The fine silt reservoir is defined as a reservoir unit with a width of 1.0 mm, a length of 1.5 mm, and a height of 0.2 mm, with a boundary wall thickness of 0.5 mm. A denser fluid grid is used in the fine silt reservoir near the screen assembly, while the remaining portion of the reservoir is also a fluid grid. The mesh size in the denser fluid grid region is 0.2 mm, and the mesh size in the non-dense fluid grid region is 1.3 mm. Coupled simulations based on the Discrete Element Method (DEM) and Computational Fluid Dynamics (CFD) show that, under the same apparent accuracy conditions (apparent accuracy refers to the average total opening area of the mesh / slot, i.e., the average flow area), compared to a homogeneous multilayer sand control screen, the gradient structure multilayer sand control screen of this invention can effectively alleviate clogging and prolong the duration of sand control while ensuring sand control effectiveness. Its sand output and maximum sand output rate are reduced by more than 50%, and permeability and pressure gradient losses are reduced by 15% to 35%. This invention's structure is suitable for fine-grained sand reservoirs with poor pore permeability or high clay content, providing theoretical and technical support for the safe and efficient exploitation of oil, gas, and natural gas hydrates.
[0026] The simulation involved in this embodiment 2 takes a muddy fine sand natural gas hydrate reservoir in the South China Sea as the research object. A numerical model of screen sand blocking is constructed. Under the premise of the same overall apparent accuracy, the sand blocking performance of uniform structure and gradient structure are compared respectively. The parameters of the fluid sand carrying and sand blocking numerical model are shown in Table 1.
[0027] Simulation results show that under a uniform structure, particles tend to form a cake quickly on the outside of the medium, leading to a rapid decrease in porosity and permeability; while under a gradient structure, particles are trapped inside the medium step by step, the external cake becomes significantly thinner, and the clogging phenomenon is alleviated.
[0028] In terms of sand discharge characteristics, compared with uniform structure sand control screens, gradient structure sand control screens significantly reduce the amount of sand discharged and the maximum sand discharge rate.
[0029] This screen assembly is used in the development of natural gas hydrate reservoirs, and can delay the decline in porosity in the near-wellbore area, improving the stability of seepage channels. This screen assembly can also be used for solid phase control and seepage maintenance in conventional loose sandstone reservoirs, high-mud-content oil and gas reservoirs on the seabed, or other fine-particle porous media. Compared with traditional sand control screens, this sand control screen can optimize sand production and maximum sand production rate by more than 50% during application, and optimize permeability and pressure gradient loss by 10% to 50%.
[0030] Table 1. Parameters of the numerical model for fluid-borne and sand-blocking.
[0031] 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 screen assembly suitable for use in a fine-particle sand reservoir and capable of sand control and plugging prevention, characterized in that, The screen assembly comprises a plurality of screen units stacked together from top to bottom, and the aperture of the plurality of screen units gradually decreases from the side facing the fine silt reservoir to be developed to the side facing the wellbore.
2. The screen assembly of claim 1, wherein, The screen assembly comprises a plugging prevention optimization layer (1), a basic sand prevention layer (2), and a sand prevention optimization layer (3), wherein the basic sand prevention layer (2) is arranged between the plugging prevention optimization layer (1) and the sand prevention optimization layer (3). The aperture of the plugging prevention optimization layer (1), the basic sand prevention layer (2), and the sand prevention optimization layer (3) gradually decreases from large to small.
3. The screen assembly according to claim 2, wherein The fine silt reservoir comprises large-diameter particles, small-diameter particles, and fine powder particles, The plugging prevention optimization layer (1) is configured to prevent the large-diameter particles from passing through and allow the small-diameter particles and the fine powder particles to pass through; The basic sand prevention layer (2) is configured to allow the fine powder particles and part of the small-diameter particles to pass through, while preventing the remaining small-diameter particles from passing through; The sand prevention optimization layer (3) is configured to allow only the fine powder particles to pass through, while retaining a small part of the small-diameter particles.
4. A method for applying a screen assembly suitable for use in fine-particle sand reservoirs and capable of preventing sand and plugging, characterized in that, The method comprises Step A: arranging the screen assembly according to any one of claims 1 to 3 in the fine silt reservoir, such that the plugging prevention optimization layer (1) faces the fine silt reservoir to be developed, and the sand prevention optimization layer (3) faces the wellbore; Step B: the large-diameter particles, the small-diameter particles, and the fine powder particles in the fine silt reservoir move through the screen assembly along with the fluid; Step C: as Step B continues, the large-diameter particles retained by the plugging prevention optimization layer (1), the majority of the small-diameter particles retained by the basic sand prevention layer (2), and the small part of the small-diameter particles retained by the sand prevention optimization layer (3) spatially present a change in particle size from large to small, thereby forming a spatial gap with a gradually decreasing aperture from the outside to the inside, which helps to reduce the accumulation of particles in the fine silt reservoir on the plugging prevention optimization layer (1), increases the capacity of the fine silt reservoir, and thus prolongs the duration of the effective sand prevention state.
5. The method of claim 4, wherein the compound is administered in an amount of about 0.1 to 10 mg / kg. Step B comprises the following specific steps: Step B1: the large-diameter particles are retained by the plugging prevention optimization layer (1), while the small-diameter particles and the fine powder particles pass through the aperture of the plugging prevention optimization layer (1); Step B2: the fine powder particles and part of the small-diameter particles pass through the aperture of the basic sand prevention layer (2), while the remaining small-diameter particles are retained by the basic sand prevention layer (2); Step B3: only the fine powder particles pass through the sand prevention optimization layer (3), and a small part of the small-diameter particles are retained by the sand prevention optimization layer (3).