ICD water control screen pipe structure of fractured reef limestone oil reservoir

Abstract

The invention discloses an ICD water control screen pipe structure of a fractured reef limestone oil reservoir. The ICD water control screen pipe structure of the fractured reef limestone oil reservoir comprises a well wall and an ICD water control screen pipe column. The well wall comprises a horizontal production section, the ICD water control screen pipe column is located in the well wall, the ICD water control screen pipe column comprises filtering sections and blind pipe sections which are alternately connected in the horizontal production section, and the length ratio of the filtering sections to the blind pipe sections which are alternately connected in the horizontal production section is 1: 1. The screen blind ratio of the ICD water control screen pipe column in the horizontal production section of the well wall is set to be 1: 1 so as to adapt to the special geological conditions of the fractured reef limestone oil reservoir, inflow distribution of fluid in the fractured reef limestone oil reservoir can be effectively balanced, excessive fluid production of the high-permeability fractured section is restrained, the bottom water coning risk is reduced, and the water control effect and the well completion effect are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of oil well completion technology, and in particular to an ICD water control screen structure for fractured reef limestone reservoirs. Background Technology

[0002] In oil extraction, the rationality of the ICD (Inflow Control Device) water control screen structure directly affects well productivity and lifespan. ICD water control screens combined with continuous packer particle packing completion technology, as a mature completion method, has been widely used in various reservoirs. However, fractured reef limestone reservoirs have unique geological conditions, such as strong heterogeneity (extreme discontinuity and disorder in the spatial distribution, physical properties, and fluid flow behavior of the "matrix-fracture" dual-medium system), uneven fracture distribution (with high-permeability sections with well-developed fractures and low-permeability sections with fewer fractures), and a high risk of bottom water coning. Traditional ICD water control screen structures in such reservoirs easily lead to uneven fluid inflow distribution along the tubing string, resulting in bottom water coning and crossflow in high-permeability sections.

[0003] In addition, the ICD water control screen string in the traditional ICD water control screen structure will hinder the full filling of the continuous packer particles in the curved annular space at the heel end, resulting in insufficient filling compaction, inability to effectively seal the production section, easy to cause inter-layer flow, and seriously affect the oil well production efficiency and life. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to address at least one defect of the related technologies mentioned in the background: the traditional ICD water control screen structure is prone to causing uneven flow and distribution of fluid on the tubing in fractured reef limestone reservoirs, and to provide an ICD water control screen structure for fractured reef limestone reservoirs.

[0005] The technical solution adopted by the present invention to solve its technical problem is: to construct an ICD water control screen structure for fractured reef limestone reservoirs, wherein the ICD water control screen structure for fractured reef limestone reservoirs includes a wellbore and an ICD water control screen string. The wellbore includes a horizontal production section, and the ICD water control screen string is located inside the wellbore. The ICD water control screen string includes filter sections and blind pipe sections that are alternately connected within the horizontal production section. The length ratio of the filter sections to the blind pipe sections that are alternately connected within the horizontal production section is 1:1.

[0006] In some embodiments, the wellbore further includes a non-production section, and the horizontal production section is connected to the non-production section; The ICD water control screen structure of the fractured reef limestone reservoir also includes a casing, which is fixed on the non-production section; The ICD water control screen tube column also includes a root end blind tube section located inside the casing and at the root end, and at least one ICD water control screen tube located inside the casing, wherein the root end refers to the end of the horizontal production section near the non-production section.

[0007] In some embodiments, the length of the heel-end blind tube segment is 1m-5m.

[0008] In some embodiments, the ICD water control screen string forms an annular space between the inner wall of the casing and the well wall, respectively. The annular space is used to fill continuous packer particles, which are resin particles.

[0009] In some embodiments, the resin particles are made of one or more of polyethylene, polypropylene, polyvinyl chloride, and styrene-divinylbenzene crosslinked copolymers.

[0010] In some embodiments, the continuous packing particles have a particle size of 0.10-1.8 mm and an actual density of 0.9-1.2 g / cm³.

[0011] In some embodiments, the annular space is used for filling with a filling fluid carrying the continuous packer particles.

[0012] In some embodiments, the ICD water control screen structure of the fractured reef limestone reservoir further includes a packer, and the packer is provided around the ICD water control screen connected to the heel blind pipe section inside the casing.

[0013] In some embodiments, the filtration section includes a screen tube, an ICD flow control device, a flow guide layer, and a protective layer; The ICD flow control device is arranged at intervals along the axial direction on the screen tube oil pipe and is in communication with the inside of the screen tube oil pipe. The flow guiding layer is sleeved on the outside of the screen tube oil pipe, and the protective layer is sleeved on the outside of the flow guiding layer. The flow guiding layer is used to filter and guide the fluid.

[0014] In some embodiments, the filtration precision of the diversion layer is selected based on the geological type of the fractured reef limestone reservoir and the particle size range of the continuous packing material.

[0015] By implementing this invention, the following beneficial effects are achieved: This invention sets the blind screen ratio of the ICD water control screen string to 1:1 in the horizontal production section of the wellbore to adapt to the special geological conditions of fractured reef limestone reservoirs. It can effectively balance the inflow distribution of fluids in fractured reef limestone reservoirs, suppress excessive production in high-permeability fracture sections, reduce the risk of bottom water coning, and significantly improve water control and well completion effects. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings: Figure 1 The diagram shows a structural diagram of an embodiment of the ICD water control screen structure for fractured reef limestone reservoirs of the present invention. The filter section and blind pipe section shown are only for illustrative purposes and are not intended to be limiting. The text description shall prevail. Figure 2 The diagram shows a cross-sectional view of an embodiment of the filter section of the ICD water control screen string in the ICD water control screen structure for fractured reef limestone reservoirs of the present invention. The opening size, density and position of the metal mesh layer shown are for illustrative purposes only and are not intended to be limiting. The opening size, density and position may be different in the actual product. The accompanying figure is labeled as follows: Wellbore 1; Horizontal production section 11; Non-production section 12; Heel end 13; ICD water control screen tubing string 2; Filter section 21; Screen tubing 211; ICD flow control device 212; Guide layer 213; Protective layer 214; Blind pipe section 22; Heel end blind pipe section 22a; Casing 3; Continuous packer particles 4; Packer 5. Detailed Implementation To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0017] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0018] In the description of this invention, it should be understood that the terms "center," "upper," "lower," "front," "rear," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0019] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "fixed," "connected," "linked," "located in," and "located in" should be interpreted broadly. For example, they can refer to a fixed connection (or an integral structure), a detachable connection, a mechanical connection, a chemical connection, a direct connection, or an indirect connection through an intermediate medium. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0020] The following at least one (segment, layer) can be one (segment, layer), two (segment, layer), three (segment, layer), or any number. Multiple roots (layers) can be two (layers), three (layers), or any number.

[0021] Wellbore: A physical channel through which oil is drilled from the surface to an underground oil reservoir.

[0022] Wellbore: The wellbore is the entire natural inner wall of the drilled wellbore, extending from the wellhead to the bottom. It is composed of all the formation rocks drilled through, covering the entire depth of the wellbore, and is divided into two parts: the production section and the non-production section. The production section is the part of the wellbore that completely overlaps with the effective oil-producing area of ​​the reservoir, and is located in the deep reservoir area of ​​the wellbore (such as the reef limestone section of a fractured reef limestone reservoir). The remaining sections of the wellbore (the shallow and intermediate layers without oil reservoirs) are non-production sections and have no value for crude oil extraction.

[0023] ICD water control screen string: a core completion tool used to balance fluid production and delay water vapor breakthrough.

[0024] The filter section of the ICD water control screen string allows formation fluids (oil, gas, water) to enter the string while blocking formation solid particles (sand, mud), making it the core component of sand control.

[0025] The blind section of the ICD water control screen tube string is a completely sealed, non-porous section of the tube string, whose interior serves as a channel for collecting and transporting fluids.

[0026] Bottom water coning: Active bottom water, driven by pressure difference, preferentially and rapidly advances in a finger-like pattern along high-permeability sections, forming local "water channeling" or "water ridges," and prematurely breaching the wellbore.

[0027] High-permeability zone crossflow: Fluid rapidly flows into the wellbore from the high-permeability zone, completely bypassing the effective oil layer in the low-permeability zone. This not only prevents the extraction of oil from the low-permeability zone, but also makes it easy for water to enter from the high-permeability zone.

[0028] like Figure 1As shown, some embodiments of the present invention disclose an ICD water control screen structure for fractured reef limestone reservoirs. This ICD water control screen structure is suitable for fractured reef limestone reservoirs and includes a wellbore 1 and an ICD water control screen string 2, as detailed below: Well wall 1 includes a horizontal production section 11. ICD water control screen pipe string 2 is located inside well wall 1. ICD water control screen pipe string 2 includes a filter section 21 and a blind pipe section 22 that are alternately connected within the horizontal production section 11. The length ratio of the filter section 21 to the blind pipe section 22 that are alternately connected within the horizontal production section 11 is 1:1, that is, the filter section 21 and the blind pipe section 22 each account for 50%.

[0029] This invention sets the blind screen ratio of the ICD water control screen string 2 in the horizontal production section 11 to 1:1 to adapt to the production scenario of fractured reef limestone reservoirs with strong heterogeneity and uneven fracture distribution. After the subsequent blind section 22 is filled with continuous packer particles 4, the resulting sealing area is large and the lateral resistance to crossflow is high. Even with the strong heterogeneity and uneven fracture distribution of fractured reef limestone reservoirs, crossflow between the production sections corresponding to the filter sections 21 at both ends of the blind section 22 is not likely to occur. This makes the flow path of the fluid in the horizontal production section 11 more uniform, forming a more balanced production pressure difference. The inflow distribution of the fluid on the string is also more uniform, and there will be no situation where the fluid inflow in a certain filter section 21 is particularly large. This can prevent the bottom water from breaking through prematurely at a local point, promote the uniform rise of the oil-water interface, and reduce the risk of bottom water coning. Furthermore, it effectively utilizes all horizontal production sections 11 (especially the low-permeability sections), suppresses excessive fluid production in high-permeability sections, expands the drainage volume, reduces residual oil, and lowers the possibility of affecting the exploitation of other areas due to excessive fluid production in a certain high-permeability section. Ultimately, it significantly improves water control, exploitation efficiency, and well completion results, providing strong technical support for the long-term stable development of the reservoir.

[0030] In some embodiments, the ICD water control screen tube column 2 includes multiple ICD water control screen tubes, each ICD water control screen tube including at least one filtration section 21 and at least one blind tube section 22.

[0031] In some embodiments, the wellbore 1 also includes a non-production section 12, which is connected to and curved in shape with respect to the horizontal production section 11, and the heel end 13 refers to the end of the horizontal production section 11 that is close to the non-production section 12.

[0032] The ICD water control screen structure for this fractured reef limestone reservoir also includes a casing 3, which is fixed to the non-production section 12. The ICD water control screen string 2 also includes a heel blind tube section 22a located inside the casing 3 at the heel end 13, and at least one ICD water control screen tube located inside the casing 3. The length of the heel blind tube section 22a is 1m-5m, for example, 1m.

[0033] Specifically, firstly, casing 3 is lowered into the non-production section 12 of well wall 1. Casing 3 reaches or approaches the horizontal production section 11 of well wall 1 and is fixed to the non-production section 12 of well wall 1 by cementing process. Then, ICD water control screen string 2 is lowered into the well wall 1. ICD water control screen string 2 is located inside casing 3 and well wall 1.

[0034] This invention uses a single blind pipe section 22a at the heel end 13 within the casing 3 (ICD water control screen string 2). The remaining portion of the casing 3 is also configured with ICD water control screens. This design, with fewer and shorter blind pipe sections, effectively reduces obstructions in the curved annular space at the heel end 13, allowing the continuous packer particles 4 to flow more smoothly and fill the annular space during filling. When the continuous packer particles 4 are injected from the wellbore, the area occupied by the outer wall of the single blind pipe section 22a at the heel end 13 is significantly reduced. This results in a more unobstructed flow channel within the curved annular space, allowing the particles to fully fill all corners under pressure. This provides ample space for the effective accumulation and compaction of the continuous packer particles 4, significantly improving the compaction of the continuous packer within the curved annular space at the heel end 13, and thus effectively sealing the horizontal production section 11.

[0035] The setting of the length of the blind tube section 22a at the heel end, which is in the range of 1m-5m, avoids the problem of insufficient structural connection stability that may be caused by the blind tube section being too short, and also prevents the continuous packer particles 4 from being obstructed at the heel end 13 due to being too long. Through precise size control, the filling effect of the continuous packer particles 4 in the horizontal production section 11 is further optimized, ensuring that they can be evenly and tightly distributed, thereby providing a more reliable structural guarantee for the effective sealing of the entire horizontal production section 11.

[0036] In some embodiments, the ICD water control screen string 2 forms annular spaces between the inner wall of the casing 3 and the wellbore 1, respectively. These annular spaces are filled with continuous packer particles 4 to form a continuous packer. The continuous packer particles 4 are resin particles, and their materials include one or more of polyethylene, high-density polyethylene, polypropylene, polyvinyl chloride, and styrene-divinylbenzene cross-linked copolymers. These polymer materials possess oil resistance, temperature resistance, and aging resistance properties to adapt to the complex downhole environment and ensure that their performance does not degrade due to chemical corrosion or temperature changes during long-term use, thereby maintaining the stability and sealing effect of the continuous packer. It should be noted that, in addition to the materials mentioned above, other polymer materials with similar properties can be selected for the continuous packer particles 4 according to the actual reservoir conditions.

[0037] In some embodiments, the particle size of the continuous packer particles 4 is 0.10-1.8 mm, and the actual density is 0.9-1.2 g / cm³. This particle size range ensures that the particles form a tight packing within the annular space, effectively blocking cross-flow, while avoiding the problem of decreased permeability caused by excessively large particles leading to incomplete packing or excessively small particles. The setting of the actual density takes into account the matching with the wellbore fluid density, ensuring that the particles can settle smoothly and be stably distributed during the packing process, while preventing migration during long-term production due to excessive density differences, further enhancing the overall sealing reliability of the continuous packer. In practical applications, the particle size and density of the continuous packer particles can be fine-tuned according to parameters such as the specific size of the annular space, the wellbore trajectory, and the formation pressure to achieve the best sealing effect.

[0038] In some embodiments, the annular space is used for filling with a filling fluid carrying continuous packing particles 4. Specifically, during the filling process, the filling fluid carries the continuous packing particles 4, and the filling rate is greater than 1 cubic meter per minute. The filling fluid can reduce the surface tension between the particles and water, allowing the particles to be evenly dispersed in the sand-carrying fluid without clumping, resulting in more uniform filling and ensuring that the particles are tightly packed. For example, the concentration of the filling fluid is 3%-15%.

[0039] In some embodiments, the ICD water control screen structure of fractured reef limestone reservoirs also includes a packer 5. A packer 5 is installed around the ICD water control screen connected to the heel blind section 22a inside the casing 3, ensuring the ICD water control screen string 2 is centered while achieving 360° uniform and dense filling. This ensures that the continuous packer particles 4 can fully cover the entire horizontal production section 11, resulting in better sealing. Simultaneously, the mechanical sealing of the packer 5 and the stepless sealing of the continuous packer particles 4 reinforce each other, providing enhanced isolation for high-water-yielding sections.

[0040] In some embodiments, such as Figure 2 As shown, the filtration section 21 includes a screen tubing 211, an ICD flow control device 212, a guide layer 213, and a protective layer 214. The ICD flow control device 212 is spaced axially along the screen tubing 211 and communicates with its interior. The guide layer 213 is fitted over the screen tubing 211, and the protective layer 214 is fitted over the guide layer 213. The guide layer 213 is used to filter and guide the fluid. Specifically, the fluid must pass through the protective layer 214 and the guide layer 213 sequentially for filtration and guidance before entering the ICD flow control device 212, and finally flowing into the screen tubing 211 and being produced at the wellhead. The ICD flow control device 212 is used to generate an additional pressure drop related to the flow rate through a fixed flow channel (such as a nozzle or spiral groove). The ICD flow control device 212 is implemented using existing technology, which is a common technique / general knowledge in the field and will not be described in detail here.

[0041] In some embodiments, the flow guiding layer 213 comprises multiple layers of metallic mesh, and the protective layer 214 comprises at least one layer of metallic mesh, such as a metal mesh fabric. Understandably, the protective layer 214 may also differ from the flow guiding layer 213. The filtration precision of the flow guiding layer 213 (or the protective layer 214 and the flow guiding layer 213) is selected based on the geological type of the fractured reef limestone reservoir (e.g., fracture density, sand production risk) and the particle size range of the continuous packing particles 4. Typically, the filtration precision is less than the minimum particle size of the continuous packing particles 4 to prevent packing particles from entering the screen tube. For example, a 40-70 mesh particle size range is 425 micrometers to 212 micrometers, and the metallic mesh layer is selected to be 150-200 micrometers.

[0042] The present invention further enhances the adaptability of the structure to fractured reef limestone reservoirs by matching the filtration accuracy of the flow guide layer 213 (or the protective layer 214 and the flow guide layer 213) with the particle size of the continuous packing particles 4, and by the synergistic effect of the ICD flow control device 212 and the flow guide layer 213, taking into account the functions of sand prevention, water control and packing.

[0043] In some embodiments, the blind pipe section 22 is a screen pipe oil pipe 211 without a protective layer 214, a flow guide layer 213 and connected to the ICD flow control device 212. It has no external filtration or flow guide structure, and the fluid cannot flow radially into the screen pipe through the blind pipe section 22.

[0044] It is understood that the above embodiments only illustrate some implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can freely combine the above embodiments or technical features without departing from the concept of the present invention, and can also make several modifications and improvements, all of which fall within the protection scope of the present invention. That is, the embodiments described "in some embodiments" can be freely combined with any of the preceding and following embodiments. Therefore, all equivalent transformations and modifications made within the scope of the claims of the present invention should be covered by the claims of the present invention.

Claims

1. An ICD water control screen structure for fractured reef limestone reservoirs, characterized in that, The ICD water control screen structure of the fractured reef limestone reservoir includes a wellbore (1) and an ICD water control screen string (2). The well wall (1) includes a horizontal production section (11), and the ICD water control screen pipe string (2) is located inside the well wall (1). The ICD water control screen pipe string (2) includes a filter section (21) and a blind pipe section (22) that are alternately connected in the horizontal production section (11). The length ratio of the filter section (21) to the blind pipe section (22) that are alternately connected in the horizontal production section (11) is 1:

1.

2. The ICD water control screen structure for fractured reef limestone reservoirs according to claim 1, characterized in that, The wellbore (1) also includes a non-production section (12), and the horizontal production section (11) is connected to the non-production section (12); The ICD water control screen structure of the fractured reef limestone reservoir also includes a casing (3), which is fixed to the non-production section (12). The ICD water control screen tube column (2) also includes a root end blind tube section (22a) located in the sleeve (3) and at the root end (13) and at least one ICD water control screen tube located in the sleeve (3), wherein the root end (13) refers to the end of the horizontal production section (11) near the non-production section (12).

3. The ICD water control screen structure for fractured reef limestone reservoirs according to claim 2, characterized in that, The length of the blind tube section (22a) at the heel end is 1m-5m.

4. The ICD water control screen structure for fractured reef limestone reservoirs according to claim 2, characterized in that, The ICD water control screen pipe string (2) forms an annular space between the inner wall of the casing (3) and the well wall (1), respectively. The annular space is used to fill the continuous packer particles (4), which are resin particles.

5. The ICD water control screen structure for fractured reef limestone reservoirs according to claim 4, characterized in that, The resin particles are made of one or more of polyethylene, polypropylene, polyvinyl chloride, and styrene-divinylbenzene cross-linked copolymers.

6. The ICD water control screen structure for fractured reef limestone reservoirs according to claim 4, characterized in that, The continuous packing particles (4) have a particle size of 0.10-1.8 mm and a true density of 0.9-1.2 g / cm³.

7. The ICD water control screen structure for fractured reef limestone reservoirs according to claim 4, characterized in that, The annular space is used to fill the continuous packer particles (4) with the filling fluid.

8. The ICD water control screen structure for fractured reef limestone reservoirs according to claim 2, characterized in that, The ICD water control screen structure of the fractured reef limestone reservoir also includes a packer (5), and the packer (5) is provided around the ICD water control screen connected to the heel blind pipe section (22a) inside the casing (3).

9. The ICD water control screen structure for fractured reef limestone reservoirs according to claim 2, characterized in that, The filter section (21) includes a screen pipe (211), an ICD flow control device (212), a flow guide layer (213), and a protective layer (214). The ICD flow control device (212) is arranged axially at intervals on the screen pipe oil pipe (211) and communicates with the inside of the screen pipe oil pipe (211). The flow guiding layer (213) is sleeved on the outside of the screen pipe oil pipe (211), and the protective layer (214) is sleeved on the outside of the flow guiding layer (213). The flow guiding layer (213) is used to filter and guide the fluid.

10. The ICD water control screen structure for fractured reef limestone reservoirs according to claim 9, characterized in that, The filtration precision of the guide layer (213) is selected based on the geological type of the fractured reef limestone reservoir and the particle size range of the continuous packing particles (4).

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