A multi-layer sand control polymer screen pipe for weakly cemented reservoirs and its preparation method

Abstract

The present invention relates to the technical field of sand control, and discloses a multi-layer sand control polymer screen for weakly cemented reservoirs, comprising: a base pipe; a waterproof layer provided on the outer side of the base pipe, the waterproof layer being used for being arranged in the pure water interlayer of the reservoir, the material of the waterproof layer being a polymer and the waterproof layer being a consolidated structure; a sand control layer structure provided on the outer side of the base pipe, the sand control layer structure being used for being arranged in the reservoir to be exploited, the material of the sand control layer structure being a polymer and the sand control layer structure being a porous medium structure. This sand control screen can set the corresponding sand control layer structure and waterproof layer according to the characteristics of the actual reservoir, avoiding the problem of a large amount of water production in the water-containing interlayer reducing the production capacity.

Description

Technical Field

[0001] The present invention relates to the technical field of sand control, and more specifically, particularly to a multi-layer sand control polymer screen pipe for weakly consolidated reservoirs and a preparation method thereof. Background Art

[0002] Existing sand control screen pipes mostly use conventional media such as pre-packed gravel, regular slot networks, and regular filter meshes as sand control structures. The sand control effect of such sand control media depends on the accurate selection of the sand control precision. If the selected sand control precision is too low, a large amount of formation sand will enter the wellbore, causing downhole accidents that affect normal production, such as equipment damage and wellbore blockage; if the selected sand control precision is too high, it is easy to cause blockage of the sand control media, reducing the production efficiency or even completely stopping the oil and gas production. However, for weakly consolidated reservoirs with a high clay content, due to the different microscopic morphologies and migration characteristics of different types of clay minerals, the sand control precision selection methods that work well in conventional reservoirs are not fully applicable here. The selection of the sand control media precision needs to be based on a highly accurate understanding of formation information such as the particle size of the reservoir sand and the clay content, and an empirical formula with a high degree of compatibility with the formation. In addition, hydrates or natural gas often occur in the reservoir in the form of thin layers. These thin layers have different thicknesses, different properties, and pure water-bearing interlayers are mixed between the layers. The large amount of water production from the water-bearing interlayers during the mining process will inevitably affect the gas production efficiency. Therefore, if such vertically highly anisotropic reservoirs are generally sand controlled, the highest efficiency mining cannot be achieved. To sum up, there is currently no sand control technical means with a high degree of compatibility with weakly consolidated reservoirs. Summary of the Invention

[0003] The purpose of the present invention is to provide a multi-layer sand control polymer screen pipe for weakly consolidated reservoirs and a preparation method thereof to solve the problems existing in the prior art.

[0004] To achieve the above purpose, the present invention provides the following solutions: The present invention provides a multi-layer sand control polymer screen pipe for weakly consolidated reservoirs, including: a base pipe; a waterproof layer disposed outside the base pipe, the waterproof layer is used for being disposed in the pure water interlayer of the reservoir, the material of the waterproof layer is a polymer, and the waterproof layer is a consolidated structure; a sand control layer structure disposed outside the base pipe, the sand control layer structure is used for being disposed in the reservoir to be mined, the material of the sand control layer structure is a polymer, and the sand control layer structure is a porous medium structure.

[0005] Further, the waterproof layer is adhered to the sand control layer structure.

[0006] Further, the sand control layer structure includes at least one sand control layer; wherein, based on the particle size information of the reservoir to be mined, the number of sand control layers is determined.

[0007] Furthermore, the sand control layer structure includes a first sand control layer and a second sand control layer, and the second sand control layer is sleeved outside the first sand control layer.

[0008] Furthermore, the pore radius of the first sand control layer is smaller than that of the second sand control layer.

[0009] Furthermore, it further includes an outer protective layer sleeved outside the waterproof layer and the sand control layer structure.

[0010] A preparation method of a multi-layer sand control polymer screen pipe for a weakly cemented reservoir includes the following steps: sleeving an inner sleeve on the inner side of the base pipe, and sleeving a first outer sleeve on the outer side of the base pipe; configuring the polymer required for the sand control layer structure, fully stirring it evenly and then injecting it into the annulus between the base pipe and the first outer sleeve. After initial setting, remove the inner sleeve and the first outer sleeve, and wait for complete consolidation to form the sand control layer structure; sleeve an inner sleeve on the inner side of the base pipe with the sand control layer structure, and sleeve a second outer sleeve on the outer side of the base pipe; configure the polymer required for the waterproof layer, fully stir it evenly and then inject it into the annulus between the base pipe and the second outer sleeve. After initial setting, remove the inner sleeve and the second outer sleeve, and wait for complete consolidation to form the waterproof layer.

[0011] Furthermore, configure the polymer required for the first sand control layer, fully stir it evenly and then inject it into the annulus between the base pipe and the first outer sleeve. After the slurry initial sets, remove the inner sleeve and the first outer sleeve, and wait for the slurry to be completely consolidated to form the first sand control layer; sleeve the second outer sleeve on the outer side of the base pipe with the first sand control layer; configure the polymer required for the second sand control layer, fully stir it evenly and then inject it into the annulus between the first sand control layer and the second outer sleeve. After the slurry initial sets, remove the second outer sleeve, and wait for the slurry to be completely consolidated to form the second sand control layer.

[0012] The present invention discloses the following technical effects:

[0013] In the present invention, a waterproof layer and a sand control layer structure are arranged on the outer side of the base pipe. Both the waterproof layer and the sand control layer structure are composed of different polymers, replacing the conventional mechanical sand control medium. During use, the waterproof layer is located in the pure aquifer of the reservoir and ensures water impermeability in the form of its consolidated body structure, and the sand control layer structure is located in the reservoir to be exploited and plays a sand blocking effect in the form of a porous medium. Based on the sand control effect evaluation, it has a good sand blocking effect on clay minerals and quartz sand of fine silt grade and has a low permeability damage. The overall structure has a high adaptability to the weakly cemented reservoir.

[0014] The porous medium formed after the consolidation of this polymer has a high porosity, strong pore connectivity and a complex pore network. Based on a large number of indoor experimental results of the inventor's previous evaluation of the sand control effect of this material, the present invention has a good sand control effect on clay minerals and quartz sands of fine sand grade and a low permeability damage;

[0015] It can achieve precise sand control under complex formation conditions. While achieving efficient sand control, it also avoids the problem that a large amount of water production in the high-water-bearing interlayer affects the gas production efficiency;

[0016] The preparation of this application is simple and the structure is concise. Different parts are connected by the self-bonding strength of the material itself, without additional fastening mechanisms and separation mechanisms, increasing the service life of the sand control screen pipe, reducing the maintenance cost, and also avoiding the situation of sand control failure caused by the erosion damage of the separator, increasing the overall reliability of the screen pipe. Brief Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0019] Figure 2 It is a schematic diagram of the layered preparation of the sand control screen pipe;

[0020] Figure 3 It is the experimental result of the sand control effect evaluation of the sand control consolidation body;

[0021] Figure 4 It is the experimental result of the sand control effect evaluation of the pre-packed gravel;

[0022] Among them, 1. Base pipe; 2. Waterproof layer; 3. First sand control layer; 4. Second sand control layer; 5. Protective layer; 6. Inner sleeve; 7. First outer sleeve; 8. Second outer sleeve; 9. Water-bearing interlayer; 10. Reservoir. Detailed Embodiments

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0024] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] like Figure 1 and Figure 2 As shown, the present invention provides a multi-layer sand control polymer screen for weakly cemented reservoirs, comprising: a base pipe 1; a waterproof layer 2 disposed outside the base pipe 1 and intended for installation in a pure water interlayer of the reservoir 10; the waterproof layer 2 is made of a polymer and has a consolidated structure; and a sand control layer structure disposed outside the base pipe 1 and intended for installation in the reservoir 10 to be mined; the sand control layer structure is made of a polymer and has a porous medium structure. The waterproof layer 2 is bonded to the sand control layer structure.

[0026] The sand control layer structure includes at least one sand control layer. The number of sand control layers depends on the particle size distribution and sorting of the formation sand. For some reservoirs 10 with relatively concentrated particle sizes, a single layer of sand control medium in the radial direction can meet the sand control requirements, and a single layer of sand control layer structure can be used.

[0027] In this embodiment, the sand control layer structure includes a first sand control layer 3 and a second sand control layer 4. The first sand control layer 3 is arranged on the outside of the base pipe 1, and the second sand control layer 4 is arranged on the outside of the first sand control layer 3. The waterproof layer 2 is arranged on the outside of the base pipe 1 and is located on the top of the first sand control layer 3 and the second sand control layer 4. A protective layer 5 is arranged on the outside of the waterproof layer 2 and the second sand control layer 4.

[0028] The base pipe 1 is made of a perforated seamless steel pipe made of common carbon steel such as J55, N80, or P110, with a pore diameter of 10 mm and a pore density of 50-100 pores / m. The protective layer 5 is a single-layer metal mesh made of 304 stainless steel, 0.5-1 mm thick, and with a mesh size of 10-20. It is worth noting that the sand and water-repellent functions of the present invention are primarily achieved by the first sand control layer 3, the second sand control layer 4, and the waterproof layer 2. Therefore, the present invention does not place excessive demands on the properties of the base pipe 1 and the outer protective layer 5; they only need to meet strength requirements and minimize clogging.

[0029] The waterproof layer 2, the first sand control layer 3 and the second sand control layer 4 are all polymers. This polymer is configured on the ground and filled in the corresponding parts in a slurry state before solidification. It relies on its own bonding strength to achieve adhesion of different parts of the screen pipe without the need for additional fastening and separation mechanisms.

[0030] The first sand control layer 3 is arranged in the annulus formed between the base pipe 1 and the first outer casing 7. When filling the first sand control layer 3, an inner casing 6 is inserted into the base pipe 1, and the first outer casing 7 is fixed outside the base pipe 1. At this time, an annulus is formed between the base pipe 1 and the first outer casing 7, and the polymer of the first sand control layer 3 is filled into it. After the slurry solidifies, the first sand control layer 3 is formed. The first sand control layer 3 is a porous medium with both mechanical strength and high flow conductivity. It has high porosity, high pore connectivity, and a complex pore network, which can effectively prevent sand while greatly reducing the risk of blockage.

[0031] The second sand control layer 4 is arranged in the annulus formed between the first sand control layer 3 and the second outer casing 8. The second outer casing 8 is fixed outside the base pipe 1 and the first sand control layer 3, and the polymer of the second sand control layer 4 is filled into the annulus between the first sand control layer 3 and the second outer casing 8. After the slurry solidifies, the second sand control layer 4 is formed. The second sand control layer 4 is a porous medium with both mechanical strength and high flow conductivity. It has high porosity, high pore connectivity, and a complex pore network, which can effectively prevent sand while greatly reducing the risk of blockage.

[0032] The porous medium formed after the polymerization of the first sand control layer 3 and the second sand control layer 4 has a stable and adjustable pore size, pore structure, and porosity. The pore radius of the first sand control layer 3 is smaller than that of the second sand control layer 4. The second sand control layer 4 is used to block the coarser components of the sediment in the formation, while the first sand control layer 3 is used to further block the finer components of the sediment in the formation.

[0033] The thicknesses of the waterproof layer 2, the first sand control layer 3, and the second sand control layer 4 completely depend on the thicknesses of the water-bearing interlayer 9 and the reservoir 10.

[0034] The waterproof layer 2 is arranged in the annulus formed between the base pipe 1 and the second outer casing 8, and is located above the first sand control layer 3 and the second sand control layer 4. When filling the waterproof layer 2, the inner casing 6 is inserted into the interior of the base pipe 1, the second outer casing 8 is fixed outside the base pipe 1, and the polymer of the waterproof layer 2 is filled into the annulus at the top of the first sand control layer 3 and the second sand control layer 4. After the slurry is consolidated, the waterproof layer 2 is formed. The waterproof layer 2 corresponds to the water-bearing interlayer 9 between the reservoirs 10 and is not involved in gas production. Its function is to completely block the production of water and sand. The first sand control layer 3 and the second sand control layer 4 correspond to the reservoirs 10 to be exploited. While ensuring the sand control effect, it is necessary to prevent the gas production channels from being blocked by sediment as much as possible. Based on the above different functional requirements, the polymer formulations of the waterproof layer 2, the first sand control layer 3 and the second sand control layer 4 are adjusted respectively, so that the polymer of the waterproof layer 2 will form a high-strength and waterproof consolidation body after consolidation to block the production of water in the high-water-bearing interlayer 9; the polymers of the first sand control layer 3 and the second sand control layer 4 will form a porous medium with both mechanical strength and high flow conductivity after consolidation, which has high porosity, high pore connectivity and a complex pore network, reducing the risk of blockage to a great extent while efficiently controlling sand.

[0035] The outer diameter of the inner casing 6 should be equal to or slightly smaller (not exceeding 1 mm) than the inner diameter of the base pipe 1, and the wall thickness is 1 - 2 mm; the inner diameters of the first outer casing 7 and the second outer casing 8 depend on the radial thickness of the first sand control layer 3 and the second sand control layer 4, and the wall thickness is 1 - 2 mm; the inner casing 6, the first outer casing 7 and the second outer casing 8 only play a role in supporting and shaping before the slurry in the present invention is consolidated, and there are no special requirements for the material. Materials with low cost and not easily cemented with the slurry can be selected, such as PVC cylindrical pipes, etc.

[0036] A preparation method for a multi-layer sand control polymer screen pipe for weakly cemented reservoirs is as follows:

[0037] The inner casing 6 is sleeved inside the base pipe 1;

[0038] The polymer required for the sand control layer structure is configured, fully stirred and then injected into the annulus between the base pipe 1 and the first outer casing. After initial setting, the inner casing 6 and the first outer casing 7 are removed, and waiting for complete consolidation to form the sand control layer structure;

[0039] The inner casing 6 is sleeved inside the base pipe 1 with the sand control layer structure, and the second outer casing is sleeved outside the base pipe 1;

[0040] The polymer required for the waterproof layer 2 is configured, fully stirred and then injected into the annulus between the base pipe 1 and the second outer casing 8. After initial setting, the inner casing 6 and the second outer casing 8 are removed, and waiting for complete consolidation to form the waterproof layer 2.

[0041] Specifically: Prepare the polymer required for configuring the first sand control layer 3, inject it into the annulus between the base pipe 1 and the first outer casing 7 after fully stirring and mixing evenly, remove the inner casing 6 and the first outer casing 7 after initial setting, and wait for the slurry to fully consolidate to form the first sand control layer 3.

[0042] Place the base pipe 1 with the first sand control layer 3, the outer protection layer 5, and the second outer casing 8, prepare the polymer required for configuring the second sand control layer 4, inject it into the annulus between the first sand control layer 3 and the second outer casing 8 after fully stirring and mixing evenly, remove the second outer casing 8 after initial setting, and wait for full consolidation to form the second sand control layer 4.

[0043] Place the inner casing 6, the base pipe 1 with the first sand control layer 3 and the second sand control layer 4, the outer protection layer 5, and the second outer casing 8, prepare the polymer required for configuring the waterproof layer 2, inject it into the annulus between the base pipe 1 and the second outer casing 8 after fully stirring and mixing evenly, remove the inner casing 6 and the second outer casing 8 after initial setting, and wait for full consolidation to form the waterproof layer 2, then the sand control screen pipe is manufactured.

[0044] The volume of the polymer in this application is basically unchanged before and after consolidation, and the injection volume of the polymer in all steps depends on the volume of the required sand control medium.

[0045] The sand control screen pipe provided by this application uses multi-layer polymers to replace the conventional mechanical sand control medium. The porous medium formed after the consolidation of this polymer has a high porosity, strong pore connectivity, and a complex pore network. The sand control medium used in this application has a good sand control effect on clay minerals and quartz sand of the silt and fine sand grades and has a low permeability damage. This application is simple to prepare, has a concise structure, and the different parts are connected by the self-bonding strength of the material itself, without additional fastening mechanisms and separation mechanisms. This application can be applied to complex formations with strong interlayer anisotropy to achieve precise sand control, that is, while efficiently controlling sand, it also avoids the problem that a large amount of water production in the high-water-bearing interlayer 9 affects the gas production efficiency.

[0046] As Figure 3 、 Figure 4 shown, sand control effect evaluation experiments of quartz sand and illite were carried out respectively using the sand control consolidated body in the present invention and conventional pre-packed gravel. The median particle sizes of the quartz sand and illite used in the experiment were both 10 μm. The apparent permeability in (a) refers to the ratio of the real-time permeability of the sand control medium to the initial permeability. The smaller the apparent permeability, the greater the permeability damage; (b) shows the sand production amounts in different time periods (1 hour, 2 hours, 3 hours, 4 hours, and 5 hours). The smaller the sand production amount, the better the sand control effect. The experimental results show that the sand control consolidated body used in the present invention has an excellent blocking effect on silt and fine sand grade mud and sand, and compared with traditional gravel sand control, it basically does not cause permeability damage during the sand control process and has a small risk of blockage.

[0047] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

[0048] The embodiments described above are only descriptions of the preferred modes of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A multi-layer sand control polymer screen pipe for weakly cemented reservoirs, characterized in that, Comprising: a base pipe (1); a waterproof layer (2) disposed outside the base pipe (1), the waterproof layer (2) being for being disposed in the pure water interlayer of the reservoir (10), the material of the waterproof layer (2) being a polymer and the waterproof layer (2) being a consolidated structure; a sand control layer structure disposed outside the base pipe (1), the sand control layer structure being for being disposed in the reservoir to be exploited, the material of the sand control layer structure being a polymer and the sand control layer structure being a porous medium structure; the waterproof layer (2) is adhered to the sand control layer structure; wherein, based on the particle size information of the reservoir to be exploited, the number of layers of the sand control layer is determined; the sand control layer structure includes a first sand control layer (3) and a second sand control layer (4), and the second sand control layer (4) is sleeved outside the first sand control layer (3); the pore radius of the first sand control layer (3) is smaller than that of the second sand control layer (4); also includes an outer protective layer (5) sleeved outside the waterproof layer (2) and the sand control layer structure; wherein, the first sand control layer (3) is disposed in the annulus formed between the base pipe (1) and the first outer sleeve (7). When filling the first sand control layer (3), an inner sleeve (6) is inserted into the base pipe (1), and the first outer sleeve (7) is fixed outside the base pipe (1). At this time, an annulus is formed between the base pipe (1) and the first outer sleeve (7), and the polymer of the first sand control layer (3) is filled therein. After the slurry is consolidated, the first sand control layer (3) is formed; a second outer sleeve (8) is fixed outside the base pipe (1) and the first sand control layer (3), and the second sand control layer (4) is disposed in the annulus formed between the first sand control layer (3) and the second outer sleeve (8); the waterproof layer (2) is disposed in the annulus formed between the base pipe (1) and the second outer sleeve (8) and is located above the first sand control layer (3) and the second sand control layer (4).

2. A preparation method of a multi-layer sand control polymer screen pipe for a weakly cemented reservoir, characterized in that, A method for preparing the multi-layer sand control polymer screen pipe for weakly cemented reservoir according to claim 1, comprising the following steps: an inner sleeve (6) is sleeved inside the base pipe (1), and a first outer sleeve (7) is sleeved outside the base pipe (1); the polymer required for the sand control layer structure is configured, fully stirred and evenly injected into the annulus between the base pipe (1) and the first outer sleeve (7). After initial setting, the inner sleeve (6) and the first outer sleeve (7) are removed, and after complete consolidation, the sand control layer structure is formed; an inner sleeve (6) is sleeved inside the base pipe (1) with the sand control layer structure, and a second outer sleeve (8) is sleeved outside the base pipe (1); the polymer required for the waterproof layer (2) is configured, fully stirred and evenly injected into the annulus between the base pipe (1) and the second outer sleeve (8). After initial setting, the inner sleeve (6) and the second outer sleeve (8) are removed, and after complete consolidation, the waterproof layer (2) is formed.

3. The preparation method of the multi-layer sand control polymer screen pipe for weakly cemented reservoirs according to claim 2, characterized in that: The sand control layer structure includes a first sand control layer (3) and a second sand control layer (4). The second sand control layer (4) is sleeved outside the first sand control layer (3). The method for forming the sand control layer structure by configuring the polymer required for the sand control layer structure, fully stirring it evenly and then injecting it into the annulus between the base pipe (1) and the first outer sleeve pipe (7), removing the inner sleeve pipe (6) and the first outer sleeve pipe (7) after initial setting, and waiting for complete consolidation further includes: Configuring the polymer required for the first sand control layer (3), fully stirring it evenly and then injecting it into the annulus between the base pipe (1) and the first outer sleeve pipe (7), removing the inner sleeve pipe (6) and the first outer sleeve pipe (7) after initial setting, and waiting for complete consolidation to form the first sand control layer (3); Sleeving a second outer sleeve pipe (8) outside the base pipe (1) with the first sand control layer (3); Configuring the polymer required for the second sand control layer (4), fully stirring it evenly and then injecting it into the annulus between the first sand control layer (3) and the second outer sleeve pipe (8), removing the second outer sleeve pipe (8) after initial setting, and waiting for complete consolidation to form the second sand control layer (4).

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