Soluble perforated pipe fittings

Abstract

This application provides a soluble perforated pipe fitting, relating to the field of oilfield development technology. The soluble perforated pipe fitting includes: a pipe fitting having an inner wall and an outer wall, with multiple channels penetrating the inner and outer walls, the channels including interconnected large-diameter and small-diameter sections, the large-diameter section facing the inner wall and the small-diameter section facing the outer wall; and a soluble plugging component, the outer contour of which matches the inner contour of the corresponding large-diameter and small-diameter sections, and the soluble plugging component is sealed to the large-diameter and small-diameter sections, used to close the channels; the soluble plugging component is configured to dissolve under the action of a dissolving liquid, opening the channels. When subjected to pressure differences between the inside and outside of the casing, the soluble plugging component will not slip or detach towards the outer wall of the pipe fitting, ensuring long-term sealing reliability before dissolution and preventing premature failure due to vibration, pressure fluctuations, or temperature changes.

Description

Technical Field

[0001] This application relates to the field of oilfield development technology, and in particular to a soluble perforated pipe fitting. Background Technology

[0002] In oil and gas reservoir development, drilling tools are typically used to drill underground channels. Casing extends into these channels and is supported against their sidewalls to prevent formation collapse. Perforating tools are then inserted into the casing to reach the target well section. Perforation is then performed using the perforating tools to create a connection between the formation and the casing. This allows oil and gas from the formation to flow into the casing through this connection and ultimately be extracted to the surface. However, the casing is prone to deformation under formation pressure, which can prevent the perforating tools from passing through the deformed areas to reach the target well section, thus hindering perforation operations.

[0003] In related technologies, patent application number 202010602203.3 discloses a method for initiating fractures in a casing well without perforation. This method involves setting a slit on the casing, filling the slit with a soluble material, and using water to dissolve the soluble material to open the slit, thereby establishing a communication channel between the formation and the casing.

[0004] However, the connection strength between the soluble material and the cut of the casing is insufficient. When the casing extends into the underground passage, leakage is likely to occur at the cut under the pressure inside the casing. Summary of the Invention

[0005] This application provides a soluble perforated pipe fitting to overcome the problem in the prior art where the connection strength between the soluble material and the cut of the casing is insufficient, and leakage easily occurs at the cut under the pressure inside the casing when the casing is extended into the underground passage.

[0006] This application provides a soluble perforated pipe fitting, comprising: a pipe fitting having an inner wall and an outer wall, and a plurality of channels penetrating the inner wall and the outer wall, the channels including a large-diameter section and a small-diameter section that are interconnected, the large-diameter section facing the inner wall and the small-diameter section facing the outer wall.

[0007] A soluble plugging component is disposed within the channel. The outer contour of the soluble plugging component matches the inner contours of the corresponding large-diameter section and the small-diameter section, and the soluble plugging component is sealed to the large-diameter section and the small-diameter section. The soluble plugging component is used to seal the channel.

[0008] The soluble plugging component is configured to dissolve under the action of a dissolving liquid, thereby opening the channel.

[0009] In one possible implementation, the channel extends radially along the pipe fitting, and a shoulder is formed between the large-diameter section and the small-diameter section, the shoulder facing the inner wall.

[0010] The soluble plugging component includes a head and a tail connected to the head. The head is disposed within the large diameter section, and the tail is disposed within the small diameter section. A sealing end face is provided at one end of the head facing the shoulder surface, and the sealing end face abuts against the shoulder surface.

[0011] In one possible implementation, the inner circumferential surface of the large-diameter section and / or the small-diameter section is provided with an internal thread, and the outer circumferential surface of the soluble plug is provided with an external thread that matches the internal thread. The soluble plug is connected to the internal thread by the engagement of the external thread and the internal thread.

[0012] In one possible implementation, the plurality of channels are arranged in a spiral interval along the axial direction of the pipe fitting.

[0013] Alternatively, multiple channels may be arranged in multiple layers at intervals along the axial direction of the pipe fitting, with each layer having multiple channels, and the channels in each layer being arranged at intervals around the circumference of the pipe fitting.

[0014] In one possible implementation, the outer wall is used to fit against the underground passage, and the outer end face of the soluble sealing element is flush with the surface of the outer wall.

[0015] Alternatively, the outer end face of the soluble plug is lower than the outer wall.

[0016] In one possible implementation, the length of the soluble plugging member from the inner wall to the outer wall is greater than or equal to 3 mm and less than or equal to 20 mm.

[0017] In one possible implementation, a seal is further included, the seal being disposed between the soluble plug and the channel, the seal being used to seal the gap between the soluble plug and the channel.

[0018] In one possible implementation, the cross-section of the channel is circular, elongated, slit-shaped, elliptical, rectangular, or rhomboid.

[0019] In one possible implementation, the pipe is divided into multiple target well sections along the axial direction, and each target well section is provided with multiple channels.

[0020] In one possible implementation, multiple soluble plugging components within the same target well section are dissolved by the same dissolving liquid, while soluble plugging components within multiple different target well sections are dissolved by different dissolving liquids.

[0021] This application provides a soluble perforated pipe fitting. By pre-fabricating channels penetrating the inner and outer walls of the fitting, and installing soluble plugs within these channels that precisely match the large-diameter and small-diameter sections, the casing maintains a complete seal during the running-in and cementing phases. When communication between the casing and the formation needs to be established, a dissolving fluid is used to directionally dissolve the soluble plugs, thus enabling perforation without relying on conventional perforation tools to traverse complex well sections. The shoulder surface between the large-diameter and small-diameter sections provides axial restraint for the soluble plugs, preventing them from slipping or detaching towards the outer wall of the fitting when subjected to pressure differentials between the inside and outside of the casing. This ensures the long-term sealing reliability of the soluble plugs before dissolution and prevents premature failure due to vibration, pressure fluctuations, or temperature changes. Attached Figure Description

[0022] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0023] Figure 1 This is a structural schematic diagram of the soluble perforated pipe fitting provided in this application;

[0024] Figure 2 A partial cross-sectional view of the soluble perforated pipe fitting provided in this application;

[0025] Figure 3 A schematic diagram of the structure of a channel in one embodiment of the soluble perforated pipe fitting provided in this application;

[0026] Figure 4 for Figure 3 A schematic diagram of the soluble plugging component corresponding to the channel in the soluble perforated pipe fitting provided in the document;

[0027] Figure 5 This is a schematic diagram of another embodiment of the channel in the soluble perforated pipe fitting provided in this application.

[0028] Explanation of reference numerals in the attached figures:

[0029] 100 - Pipe fitting; 110 - Inner wall; 120 - Outer wall; 130 - Target well section;

[0030] 200 - Channel; 210 - Large diameter section; 220 - Small diameter section; 230 - Shoulder surface;

[0031] 300 - Soluble plug; 310 - Head; 320 - Tail; 330 - Sealing end face;

[0032] 400 - Seals.

[0033] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0034] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0035] The terms "first," "second," "third," etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein.

[0036] Secondly, it should be noted that in the description of this application, the terms "inner", "outer", "first direction", "second direction", etc., indicating the direction or positional relationship are based on the direction or positional relationship shown in the drawings. This is only for the convenience of description and does not indicate or imply that the device or component must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this application.

[0037] Furthermore, it should be noted that, in the description of this application, unless otherwise expressly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0038] As the background technology demonstrates, in the development of unconventional oil and gas reservoirs, it is necessary to drill holes in the casing using a perforating gun to establish a connection between the casing wellbore and the formation. However, under complex geological conditions, the target well section often cannot be perforated smoothly due to casing deformation (such as elliptical deformation, diameter reduction, bending, etc.), thus making it impossible to carry out perforation operations.

[0039] To address the perforation challenge in casing deformation sections, related technologies have proposed perforation-free solutions. For example, patent application number 202010602203.3 discloses a perforation-free fracture initiation method for casing wells. This method involves creating a slit on the casing, filling the slit with a soluble material, and using water to dissolve the soluble material to open the slit, thereby establishing a communication channel between the formation and the casing, replacing traditional perforation operations.

[0040] However, during downhole operations such as casing installation, cementing, and pressure testing, the soluble material at the cut is subjected to internal pressure loads from the inner wall to the outer wall (internal pressure acts on the effective pressure-bearing area of ​​the soluble material to generate outward thrust), tensile and compressive stresses caused by wellbore bending, and thermal expansion and contraction stresses caused by temperature changes. Under the combined loads mentioned above, the soluble material is prone to fragmentation, crushing, or complete detachment, leading to premature leakage at the cut.

[0041] Understandably, the insufficient reliability of the connection between the soluble material and the casing cut can lead to leakage or failure of the perforation during well running, cementing, and early construction stages, affecting the overall sealing and pressure-bearing capacity of the casing and restricting the engineering application of perforation-free technology.

[0042] Furthermore, in actual engineering projects, a well typically only experiences casing deformation in a localized section, while the casing diameter remains normal in most other sections. The aforementioned approach involves prefabricating numerous slots and uniformly filling them with soluble material before casing installation. During operation, water or other dissolving liquid is injected into the casing to simultaneously or completely open all slots in the entire well section. This approach cannot selectively open specific deformed sections locally or at fixed points.

[0043] This setup not only results in the indiscriminate consumption of dissolving fluid and soluble materials, but more seriously, for non-deformable well sections, perforation operations that could have been completed efficiently and accurately with conventional perforation guns are now passively opened by dissolution, resulting in the loss of controllability of the perforation hole geometry parameters (hole diameter, hole depth, phase angle), which affects the initiation morphology and extension pattern of subsequent fracturing fractures.

[0044] To address the aforementioned technical problems, this application provides a soluble perforated pipe fitting, comprising: a pipe fitting having an inner wall and an outer wall, and multiple channels penetrating the inner and outer walls, the channels including interconnected large-diameter sections and small-diameter sections, the large-diameter sections facing the inner wall and the small-diameter sections facing the outer wall; a soluble plugging component disposed within the channels, the outer contour of the soluble plugging component matching the inner contour of the corresponding large-diameter and small-diameter sections, and the soluble plugging component being sealed to the large-diameter and small-diameter sections, the soluble plugging component being used to close the channels; the soluble plugging component being configured to dissolve under the action of a dissolving liquid, thereby opening the channels.

[0045] By prefabricating channels through the inner and outer walls of the casing and installing soluble plugs that precisely match the large-diameter and small-diameter sections within these channels, the casing maintains a complete seal during the running-in and cementing phases. When it is necessary to establish communication between the casing and the formation, the soluble plugs are directionally dissolved using a dissolving fluid, thus enabling perforation without relying on conventional perforation tools to traverse complex well sections. The shoulder surface between the large-diameter and small-diameter sections provides axial restraint for the soluble plugs, preventing them from slipping or detaching towards the outer wall of the casing when subjected to pressure differentials. This ensures the long-term sealing reliability of the soluble plugs before dissolution and prevents premature failure due to vibration, pressure fluctuations, or temperature changes.

[0046] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0047] This application provides a soluble perforated pipe fitting, combined with... Figure 1 and Figure 2 As shown, it includes: pipe fitting 100 and soluble plugging component 300.

[0048] The pipe fitting 100 has an inner wall 110 and an outer wall 120. The pipe fitting 100 is provided with a plurality of channels 200 that penetrate the inner wall 110 and the outer wall 120. The channels 200 include a large-diameter section 210 and a small-diameter section 220 that are interconnected. The large-diameter section 210 faces the inner wall 110 and the small-diameter section 220 faces the outer wall 120.

[0049] The soluble plugging component 300 is disposed within the channel 200. The outer contour of the soluble plugging component 300 matches the inner contour of the corresponding large-diameter section 210 and small-diameter section 220. The soluble plugging component 300 is sealed to the large-diameter section 210 and the small-diameter section 220. The soluble plugging component 300 is used to close the channel 200.

[0050] The soluble plugging component 300 is configured to dissolve under the action of a dissolving liquid, thereby opening the channel 200.

[0051] Among them, pipe fitting 100 refers to a hollow cylindrical structure used for bearing, isolating and transporting fluids downhole. As the main pressure-bearing component of soluble perforated pipe fitting, it provides an installation foundation for multiple channels 200 and soluble plugging components 300, and undertakes the functions of wellbore support, pressure isolation and structural protection during cementing and fracturing operations.

[0052] The pipe fitting 100 is located in the underground passage. The outer wall 120 of the pipe fitting 100 is attached to the ground, and the inner wall 110 forms an internal fluid channel. Each channel 200 on the pipe fitting 100 is arranged through the pipe fitting 100 along the wall thickness direction to form a pre-set connection structure that can be opened when needed.

[0053] In addition, it should be noted that the pipe fitting 100 can be a cylindrical pipe, a segmented spliced ​​pipe, or a locally thickened and reinforced pipe. Its material can be any one or more combinations of conventional oil casing steel, corrosion-resistant alloy steel, or high-strength low-alloy steel to adapt to different well depths, temperature and pressure conditions, and corrosive media environments.

[0054] Channel 200 refers to a channel structure that penetrates the inner wall 110 and outer wall 120 of pipe fitting 100 and is used to connect the interior of pipe fitting 100 with the formation when in the active state. Channel 200 is blocked by soluble plugging component 300 when closed, and forms a flow path for fracturing fluid or other working fluids to enter the formation when open, thereby replacing conventional perforation to complete the connection between pipe fitting 100 and the formation.

[0055] The large-diameter section 210 of the channel 200 refers to the enlarged diameter portion facing the inner wall 110 of the pipe fitting 100, and the small-diameter section 220 refers to the reduced diameter portion facing the outer wall 120 of the pipe fitting 100. The large-diameter section 210 and the small-diameter section 220 are interconnected and together form a stepped hole or tapered hole structure with a larger inner diameter and a smaller outer diameter, which is used to accommodate the soluble sealing component 300.

[0056] The soluble plugging component 300 refers to a consumable sealing component installed in the channel 200 for sealing the channel 200 in the early stage and failing under the action of the dissolving liquid. It achieves reliable sealing of the channel 200 by matching the contours of the large diameter section 210 and the small diameter section 220, and restores the channel 200 to connectivity by dissolving the material when it is necessary to open the hole.

[0057] The soluble plugging component 300 is located inside the channel 200 and forms a surface contact, line contact, or combined sealing interface with the wall of the channel 200. Its outer contour is adapted to the inner contour of the corresponding large-diameter section 210 and small-diameter section 220 to ensure that the channel 200 is completely sealed during casing running, cementing, waiting for solidification, and early wellbore operations.

[0058] The material of the soluble plugging component 300 can be a magnesium-based soluble alloy, an aluminum-based soluble alloy, a zinc-based soluble alloy, or a composite alloy containing an adjustable corrosion phase.

[0059] The dissolving liquid is the working liquid used to trigger the material failure of the soluble plugging component 300 and ultimately open the channel 200. It reacts chemically or electrochemically with the soluble plugging component 300, causing the plugging component to gradually lose weight, thin, and break down, thereby releasing the seal on the channel 200.

[0060] Specifically, by prefabricating a channel 200 through the inner and outer walls 120 on the pipe fitting 100, and setting a soluble plugging component 300 that precisely matches the large-diameter section 210 and the small-diameter section 220 in the channel 200, the casing can maintain a complete seal during the running-in and cementing stages. When it is necessary to establish communication between the casing and the formation, the soluble plugging component 300 is directionally dissolved with a dissolving liquid, thereby achieving hole opening without relying on conventional perforation tools to traverse complex well sections.

[0061] The shoulder surface 230 between the large diameter section 210 and the small diameter section 220 provides axial contact and limiting for the soluble plug 300, so that the soluble plug 300 will not slip or fall off towards the outer wall 120 of the pipe fitting 100 when subjected to the pressure difference between the inside and outside of the casing, thus ensuring the long-term sealing reliability of the soluble plug 300 before dissolution and preventing premature failure due to vibration, pressure fluctuation or temperature change.

[0062] In one possible implementation, combining Figure 2 , Figure 3 and Figure 4 As shown, the channel 200 extends radially along the pipe fitting 100, and a shoulder surface 230 is formed between the large diameter section 210 and the small diameter section 220, with the shoulder surface 230 facing the inner wall 110.

[0063] The soluble plugging component 300 includes a head 310 and a tail 320 connected to the head 310. The head 310 is disposed within the large diameter section 210, and the tail 320 is disposed within the small diameter section 220. A sealing end face 330 is provided at one end of the head 310 facing the shoulder surface 230, and the sealing end face 330 abuts against the shoulder surface 230.

[0064] like Figure 2 As shown, the channel 200 is arranged radially along the pipe fitting 100, so that the channel 200 can directly form an opening path connected to the outer wall 120 side within the wall thickness range of the pipe fitting 100, which facilitates the pre-fabrication of holes and the realization of radial conduction when needed.

[0065] Among them, such as Figure 3 As shown, the shoulder surface 230 formed between the large-diameter section 210 and the small-diameter section 220 constitutes a stepped support interface pointing from the inner wall 110 towards the interior of the channel 200, providing an axial positioning reference and pressure-bearing support surface for the soluble plugging component 300, and preventing the soluble plugging component 300 from axially moving under the action of downhole pressure difference, vibration or fluid scouring.

[0066] Combination Figure 2 and Figure 3As shown, the head 310 of the soluble plugging component 300 is the main load-bearing and main sealing part located in the large-diameter section 210. It can be a cylindrical head, a disc head, a frustum head, or a cap-shaped head 310 structure with rounded corners. The tail 320 is a guiding and auxiliary plugging part connected to the head 310 and extending into the small-diameter section 220. It can be a cylindrical rod, a reduced-diameter rod, a stepped rod, or a rod-shaped structure with sealing ribs. The head 310 and the tail 320 can be integrally formed, or they can be connected by welding, interference fit, or detachable connection to form an integrated plugging assembly.

[0067] Combination Figure 3 and Figure 4 As shown, the sealing end face 330 of the soluble sealing component 300 is located on the side of the head 310 facing the shoulder surface 230. The sealing end face 330 can be a flat end face, a slightly convex end face, a conical end face, or a composite end face with an annular sealing groove. After it abuts against the shoulder surface 230, it forms a surface contact or annular contact, thereby reliably sealing the connection between the large diameter section 210 and the small diameter section 220 before the channel 200 is opened.

[0068] The dimensional relationship between the large-diameter section 210 and the small-diameter section 220 is usually such that the outer diameter of the head 310 matches the inner diameter of the large-diameter section 210, and the outer diameter of the tail 320 matches the inner diameter of the small-diameter section 220. The axial length of the head 310 is preferably not less than the effective support length corresponding to the contact width of the shoulder surface 230. The length of the tail 320 can be set according to the total depth of the channel 200 and the assembly stability to ensure good coaxiality of the sealing component after radial installation and to maintain the pre-sealed pre-tightened state.

[0069] When the pipe fitting 100 is not inserted underground, the soluble plugging component 300 can be installed in the channel 200. The head 310 is confined in the large-diameter section 210, and the tail 320 can be embedded in the small-diameter section 220. The sealing end face 330 and the shoulder face 230 abut against each other to form the initial closed interface of the radial channel 200. The fluid pressure inside the pipe fitting 100 is difficult to directly penetrate this interface and enter the outside of the casing, thus keeping the orifice closed. When the dissolving liquid is subsequently injected into the pipe fitting 100, the dissolving liquid flows along the axial direction of the pipe fitting 100 and gradually contacts the soluble plugging component 300. During the dissolution process, the soluble plugging component 300 first weakens the sealing integrity near the head 310 and the shoulder face 230. Then the head 310 and the tail 320 are dissolved synchronously or in stages until a connecting cavity is formed in the channel 200 and the fluid passage inside and outside the pipe fitting 100 is restored.

[0070] Understandably, the end face contact between the shoulder surface 230 and the sealing end face 330 can provide stable positioning and reliable sealing before dissolution, preventing the soluble plugging component 300 from shifting under internal pressure, which is beneficial to improving the pressure resistance stability of the plugging component in the complex pressure environment downhole.

[0071] In addition, such as Figure 2 As shown, the large-diameter section 210 and the small-diameter section 220 of the soluble plugging component 300 can be connected to each other. The channel 200 has a conical structure, and the large-diameter section 210 faces the inner wall 110 to increase the pressure-bearing area and prevent the soluble plugging component 300 from shifting.

[0072] In one possible implementation, the inner circumferential surfaces of the large-diameter section 210 and / or the small-diameter section 220 are provided with internal threads, and the outer circumferential surface of the soluble sealing member 300 is provided with external threads that match the internal threads. The soluble sealing member 300 is connected by the engagement of the external threads and the internal threads.

[0073] With this configuration, the soluble plugging component 300 can be screwed into the channel 200 along the axial direction, forming a stable pull-out-resistant connection through threaded engagement. This prevents the soluble plugging component 300 from shifting, loosening, or deviating during well running, cementing, pressure testing, and downhole high-pressure fluctuations, thereby maintaining the closed state of the channel 200.

[0074] Of course, in different embodiments, the internal thread may be provided only on the inner circumferential surface of the major diameter section 210 to form the main locking area at the head 310, or it may be provided only on the inner circumferential surface of the minor diameter section 220, or it may be provided on both the inner circumferential surfaces of the major diameter section 210 and the minor diameter section 220 to form a double engagement constraint. It should be understood that the above thread type, material selection and size range are only illustrative and are not specific limitations.

[0075] In one possible implementation, reference is made to Figure 1 As shown, multiple channels 200 are arranged in a spiral pattern at intervals along the axial direction of the pipe fitting 100.

[0076] Or, refer to Figure 5 As shown, multiple channels 200 are arranged in multiple layers at intervals along the axial direction of the pipe fitting 100, and multiple channels 200 are arranged in each layer. The channels 200 in each layer are arranged at intervals around the circumference of the pipe fitting 100.

[0077] like Figure 1 As shown, multiple channels 200 are distributed sequentially around the axis of the pipe fitting 100 according to a spiral trajectory, so that adjacent channels 200 maintain a distance in the axial direction while offset in the circumferential direction, thereby forming a continuous or discontinuous spiral arrangement on the outer circumferential surface of the sleeve.

[0078] This configuration ensures that the fluid entering the channel 200 after it is opened is distributed circumferentially along the pipe fitting 100, preventing subsequent fracturing fluid from concentrating in the same location. This helps improve the uniformity of formation pressure and reduces the adverse effects of local stress concentration on the strength of the pipe fitting 100.

[0079] In one possible implementation, the spiral arrangement can be in the form of a single spiral, double spiral, or multiple spirals. The same or different axial spacing can be set between the channels 200 arranged along the same spiral path. Parameters such as the spiral helix angle can be matched according to the length of the pipe fitting 100, the length of the target fracturing section, and the desired opening sequence.

[0080] Of course, in one possible implementation, refer to Figure 5 As shown, multiple channels 200 can be arranged in several layers along the axial direction of the pipe fitting 100, with a predetermined axial distance between each layer, while multiple channels 200 are arranged at intervals along the circumference of the pipe fitting 100 within the same layer.

[0081] With this configuration, the pipe fitting 100 forms a discrete opening layer in the axial direction and a dispersed opening group in the circumferential direction, which facilitates the layered opening and zoned flow diversion of the channel 200 according to different target sections, different fracturing stages or different modification intensity requirements.

[0082] The number of channels 200 in each layer can be the same, or it can be adjusted according to the well section length, reservoir heterogeneity and expected stimulation scale. The circumferential spacing angle can be uniformly distributed or unevenly distributed to adapt to the restricted direction of the wellbore, the expansion trend of the main formation fracture or the entry posture of the construction tools.

[0083] The axial spacing between adjacent layers is typically larger than the size of a single channel 200 to avoid excessive reduction in casing wall thickness due to overly dense channel 200s. The circumferential arrangement angle of the channels 200 can be calculated based on the outer circumference of the casing and the predetermined coverage area to ensure a relatively balanced fluid entry surface around the wellbore after opening. The multi-layered circumferentially spaced structure can be arranged in an array, grid, or staggered pattern, suitable for staged fracturing, local perforation repair, and differentiated stimulation under complex well conditions.

[0084] It should be understood that the above-mentioned spiral spacing and multi-layer spacing are merely exemplary limitations on the spatial arrangement of channel 200. Their specific quantity, arrangement pitch, angle and number of layers can be adjusted according to working conditions and design requirements, without specific restrictions.

[0085] In one possible implementation, such as Figure 1 As shown, the outer wall 120 is used to fit into the underground passage, and the outer end face of the soluble sealing component 300 is flush with the surface of the outer wall 120.

[0086] Alternatively, the outer end face of the soluble plug 300 is 120 mm lower than the outer wall.

[0087] It is understandable that the end face of the soluble plugging component 300 facing the outer wall 120 of the pipe fitting 100 is in a state of being coplanar or nearly coplanar with the outer surface of the pipe fitting 100, or is recessed inward relative to the outer surface of the pipe fitting 100, so that the soluble plugging component 300 forms a continuous transition surface on the outer periphery of the pipe fitting 100 without producing obvious steps or sharp corners.

[0088] This configuration, while ensuring the sealing of channel 200 and its subsequent soluble opening function, minimizes the local protrusion of the outer periphery of pipe fitting 100, reduces the scraping and collision between pipe fitting 100 and the formation when it extends underground or passes through the variable diameter section, and reduces the probability of interference with the formation well wall, centralizer, scraper or other downhole tools.

[0089] Furthermore, in one possible implementation, the outer end face of the soluble sealing element 300 can be a flat surface, a slightly curved surface, or a chamfered transition surface. A flat surface facilitates a clear coplanar relationship with the outer wall 120, a slightly curved surface further improves the peripheral flow field and contact transition, while a chamfered transition surface helps reduce edge stress concentration and improve impact resistance.

[0090] Furthermore, the length of the soluble plug 300 from the inner wall 110 to the outer wall 120 is greater than or equal to 3 mm and less than or equal to 20 mm.

[0091] It is understandable that the soluble plugging component 300 is a soluble plugging component installed inside the channel 200, used to close the channel 200 during the downhole and early construction phases, and which fails to open under the action of the dissolving liquid.

[0092] The effective load-bearing length formed by the soluble plugging component 300 along the wall thickness direction of the pipe fitting 100 is the length from the inner wall 110 to the outer wall 120. The length of the soluble plugging component 300 is limited to this range. This limitation cannot guarantee a stable sealing fit between the soluble plugging component 300 and the large-diameter section 210 and the small-diameter section 220, while simultaneously enabling rapid and controllable dissolution and opening during the well opening stage, thereby improving operational reliability and construction efficiency under confined well conditions.

[0093] In one possible implementation, such as Figure 3 As shown, it also includes a seal 400, which is disposed between the soluble plug 300 and the channel 200. The seal 400 is used to seal the gap between the soluble plug 300 and the channel 200.

[0094] Among them, the seal 400 is a sealing element used to compensate for the machining tolerance between the soluble plugging element 300 and the channel 200 and to enhance the initial sealing performance. By occupying the tiny gap between the two, it forms a continuous sealing contact interface, thereby suppressing the radial or axial flow of downhole fluid at the dissolution front of the soluble plugging element 300.

[0095] The seal 400 can take the form of a sealing ring, an elastic sealing ring, a metal gasket, a composite sealing layer, or a partially filled rubber ring, etc., without any specific restrictions. Among them, sealing rings and elastic sealing rings are suitable for forming radial seals, while metal gaskets are suitable for forming end face hard seals.

[0096] In one possible implementation, combining Figure 1 and Figure 2 As shown, the cross-section of channel 200 is circular, elongated, slit-shaped, elliptical, rectangular, or rhomboid.

[0097] The cross-sectional shape of channel 200 can be pre-designed according to the expected fracturing flow rate and reservoir stimulation target. For example, a circular cross-section usually corresponds to a uniformly stressed flow structure, which is easy to process and fit, and is suitable for occasions with high requirements for structural strength and processing consistency; a long strip or slotted cross-section is elongated in one direction, which can form a larger opening area within a limited wall thickness, thereby improving the fluid flow capacity after opening and forming a more concentrated jet effect; elliptical and rectangular cross-sections can achieve a balance between orifice area and directionality, which is convenient for arrangement according to the stress distribution in the wellbore and the fracturing fracture initiation direction.

[0098] In one possible implementation, reference is made to Figure 5 As shown, the pipe fitting 100 is divided into multiple target well sections 130 along the axial direction, and multiple channels 200 are provided on each target well section 130.

[0099] Among them, the target well section 130 refers to several operating sections pre-divided along the axial length of the pipe fitting 100, which can correspond to different reservoir locations, different fracturing stages or different construction control units, and are used to realize segmented management and zoned opening on the same casing.

[0100] Each target well section 130 is equipped with multiple channels 200, which allows multiple fluid connection points to be formed within the same target well section 130, making it convenient to selectively open the corresponding channels 200 according to the transformation needs.

[0101] Multiple channels 200 on each target well section 130 can be evenly distributed around the circumference of the target well section 130, arranged in a spiral interval, or arranged in several groups in layers to adapt to the requirements of different well diameters, different trajectories, and different fracturing processes.

[0102] In one possible implementation, the length of the target well section 130 can be set as a short, medium or long section structure according to the formation thickness and the single-section fracturing length, and the number of channels 200 in each target well section 130 can be set to two, more or in groups, without specific restrictions.

[0103] Specifically, the pipe fitting 100 is divided into multiple target well sections 130 along the axial direction, so that the pipe fitting 100 can respond in segments according to the downhole operation rhythm. Each target well section 130 can be regarded as an independent modifiable unit, thereby providing a structural basis for segmented fracturing, segmented opening and differentiated dissolution control.

[0104] With this setup, during construction, after the pipe fitting 100 is lowered into the ground and cemented, multiple target well sections 130 to be modified can be determined according to the reservoir distribution. Multiple channels 200 sealed by soluble plugging components 300 are retained in the corresponding well sections. Subsequently, before and after fracturing operations, dissolving fluid can be injected sequentially according to the well sections or the opening sequence of different well sections can be controlled by time windows, so that the channels 200 in each target well section 130 are gradually dissolved and opened, forming multiple injection pathways connected to the formation.

[0105] Reference Figure 5 As shown, the channel 200 is distributed axially within multiple target well sections 130. The target well section 130 at the deformation point can be opened by dissolving the soluble plugging component 300 with the dissolving liquid. This eliminates the need for all target well sections 130 to bear the entire connection task, thereby reducing the structural weakening caused by localized opening concentration. At the same time, segmented opening achieves more uniform fracturing fluid distribution and more controllable fracture initiation location.

[0106] Furthermore, multiple soluble plugging components 300 within the same target well section 130 are dissolved by the same dissolving liquid, while soluble plugging components 300 within multiple different target well sections 130 are dissolved by different dissolving liquids respectively.

[0107] It is understandable that the differentiated configuration of the same solution and different solutions mentioned above is essentially to control the segmented opening of the channel 200 for multiple target well sections 130 after the pipe fitting 100 is divided along the axial direction.

[0108] Among them, multiple soluble plugging components 300 within the same target well section 130 can use a solution with the same chemical system, similar concentration range, or compatible reaction mechanism to ensure that when the solution is delivered to the pipe 100 and reaches the target well section 130, multiple channels 200 are opened synchronously or nearly synchronously within the same working window.

[0109] Different dissolving liquids are matched to the soluble plugging components 300 in different target well sections 130, so that adjacent well sections can be dissolved in sequence according to a predetermined time sequence, thereby realizing separate control of the timing of connection between different layers.

[0110] It should be noted that multiple soluble plugging components 300 within the same target well section 130 refer to multiple soluble plugging components 300 arranged in the same axial interval to serve the same fracturing construction section, and their function is to cooperate with the unified stimulation of the same reservoir section; different target well sections 130 refer to two or more construction sections that are spaced apart from each other in the axial direction of the pipe fitting 100, which correspond to different reservoir locations, different formation pressure conditions or different stimulation requirements.

[0111] It is understandable that when a certain target well section 130 of the pipe fitting 100 is deformed, the soluble plugging component 300 can be dissolved by conveying the dissolving liquid corresponding to the target well section 130. That is, selective opening is performed locally and at a fixed point for a specific deformed well section, while the soluble plugging component 300 at other target well sections 130 continues to block the channel 200. In other words, other undeformed target well sections 130 can continue to be opened using perforation tools.

[0112] This setup not only avoids the consumption of dissolving fluid and soluble materials, but also allows for efficient and precise perforation operations in non-deformable well sections, ensuring the controllability of perforation hole geometry parameters such as diameter, depth, and phase angle.

[0113] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A soluble perforated pipe fitting, characterized in that, include: A pipe fitting (100) having an inner wall (110) and an outer wall (120), the pipe fitting (100) having a plurality of channels (200) penetrating the inner wall (110) and the outer wall (120), the channels (200) including a large-diameter section (210) and a small-diameter section (220) communicating with each other, the large-diameter section (210) facing the inner wall (110) and the small-diameter section (220) facing the outer wall (120); A soluble plug (300) is disposed within the channel (200). The outer contour of the soluble plug (300) matches the inner contours of the corresponding large-diameter section (210) and small-diameter section (220). The soluble plug (300) is sealed to the large-diameter section (210) and the small-diameter section (220). The soluble plug (300) is used to close the channel (200). The soluble plugging element (300) is configured to dissolve under the action of a dissolving liquid, thereby opening the channel (200).

2. The soluble perforated pipe fitting according to claim 1, characterized in that, The channel (200) extends radially along the pipe (100), and a shoulder surface (230) is formed between the large diameter section (210) and the small diameter section (220), with the shoulder surface (230) facing the inner wall (110). The soluble plugging component (300) includes a head (310) and a tail (320) connected to the head (310). The head (310) is disposed within the large diameter section (210), and the tail (320) is disposed within the small diameter section (220). A sealing end face (330) is provided at one end of the head (310) facing the shoulder surface (230), and the sealing end face (330) abuts against the shoulder surface (230).

3. The soluble perforated pipe fitting according to claim 2, characterized in that, The inner circumferential surface of the large diameter section (210) and / or the small diameter section (220) is provided with an internal thread, and the outer circumferential surface of the soluble plug (300) is provided with an external thread that matches the internal thread. The soluble plug (300) is connected by the engagement of the external thread and the internal thread.

4. The soluble perforated pipe fitting according to claim 2, characterized in that, The plurality of channels (200) are arranged in a spiral pattern at intervals along the axial direction of the pipe fitting (100); Alternatively, multiple channels (200) are spaced apart along the axial direction of the pipe fitting (100) in multiple layers, with each layer having multiple channels (200) spaced apart around the circumferential direction of the pipe fitting (100).

5. The soluble perforated pipe fitting according to claim 1, characterized in that, The outer wall (120) is used to fit against the underground passage, and the outer end face of the soluble sealing member (300) is flush with the surface of the outer wall (120); Alternatively, the outer end face of the soluble plug (300) is lower than the outer wall (120).

6. The soluble perforated pipe fitting according to claim 5, characterized in that, The length of the soluble plug (300) from the inner wall (110) to the outer wall (120) is greater than or equal to 3 mm and less than or equal to 20 mm.

7. The soluble perforated pipe fitting according to claim 5, characterized in that, It also includes a seal (400) disposed between the soluble plug (300) and the channel (200), the seal (400) being used to seal the gap between the soluble plug (300) and the channel (200).

8. The soluble perforated pipe fitting according to any one of claims 1-7, characterized in that, The cross-section of the channel (200) is circular, elongated, slit-shaped, elliptical, rectangular, or rhomboid.

9. The soluble perforated pipe fitting according to any one of claims 1-7, characterized in that, The pipe fitting (100) is divided into multiple target well sections (130) along the axial direction, and each target well section (130) is provided with multiple channels (200).

10. The soluble perforated pipe fitting according to claim 9, characterized in that, Multiple soluble plugging components (300) within the same target well section (130) are dissolved by the same dissolving liquid, while multiple soluble plugging components (300) within different target well sections (130) are dissolved by different dissolving liquids respectively.

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