A ball-free metal-sealed dissolvable bridge plug

Abstract

This invention discloses a ball-free metal-sealed dissolvable bridge plug, comprising a pusher cylinder, the upper end of which is threadedly connected to a setting tool, and the lower end which is installed in the inner hole of the upper part of a ball seat; it also includes a pull rod and a conversion joint, the pull rod and the conversion joint being located at the axis, and the conversion joint, the ball seat, and the slips being sequentially fitted onto the pull rod; the conversion joint is located inside the pusher cylinder, the upper end of which is connected to the setting tool, and the lower end is located in the ball seat and threadedly connected to the pull rod; the lower end of the ball seat is sleeved with the slips; a base is fitted onto the tail of the pull rod and threadedly connected; and a dissolvable ball is located in the lower end of the conversion joint. This invention saves the step of inserting a dissolvable ball at the wellhead, improving construction efficiency, and allows for immediate verification of the bridge plug's setting status after setting, improving the reliability of bridge plug construction. The metal sealing ring has a wide temperature adaptability range and good sealing effect; the integral slips and locking structure reduce the number of tool parts, shorten the tool size, and facilitate tool insertion.

Description

Technical Field

[0001] This invention relates to the field of oil and gas field development technology, specifically to a non-ball-throwing metal-sealed soluble bridge plug. Background Technology

[0002] Currently, most soluble bridge plugs used in the market are made from soluble rubber. A characteristic of soluble rubber materials is that at high oil well temperatures, the rubber strength deteriorates rapidly, reducing sealing performance. Simultaneously, at low temperatures, its solubility decreases, resulting in prolonged dissolution times or no dissolution at all. Furthermore, rubber-sealed bridge plugs have complex structures, numerous components, and long dimensions, increasing tool costs and hindering tool insertion.

[0003] Currently, bridge plug fracturing uses a combined perforation and bridge plug setting technique. After the bridge plug is set, the cable is pulled up and deployed for perforation. Then, the perforation and setting tools are removed from the well. During fracturing, a sealing ball is deployed to seal the central channel of the bridge plug. There are two main problems: first, deploying the ball reduces operational efficiency and wastes fluid pumped into the ball; second, it cannot verify the setting of the bridge plug.

[0004] Furthermore, existing soluble bridge plug sealing components are all made of rubber, which limits their application range, has many structural components, and suffers from design flaws. They are long, have small inner diameters, and are not suitable for installation. After the bridge plug is set, a ball needs to be inserted from the wellhead to seal the central channel of the bridge plug, and the setting of the bridge plug cannot be verified, affecting work efficiency and fracturing effect. Summary of the Invention

[0005] The purpose of this invention is to address the aforementioned deficiencies in the existing technology by providing a ball-free, soluble metal-sealed bridge plug with a simple structure, few components, short length, and reliable sealing, thereby solving the defects and shortcomings of existing soluble bridge plugs in use.

[0006] A ball-free metal-sealed dissolvable bridge plug includes a pusher, the upper end of which is threadedly connected to a setting tool, and the lower end of which is installed in the inner hole of the upper part of the ball seat;

[0007] It also includes a tie rod and an adapter, which are located at the axis. The adapter, ball seat, and slip are sequentially fitted onto the tie rod.

[0008] The adapter is located inside the push cylinder. The upper end of the adapter is connected to the setting tool, and the lower end is located inside the ball seat and connected to the pull rod by a thread.

[0009] The lower end of the ball seat is fitted with the slip; the base is fitted onto the tail of the pull rod and connected by threads; the dissolvable ball is located inside the lower end of the adapter.

[0010] The pusher has a cylindrical structure, consisting of a large-diameter cylindrical surface at the top and a small-diameter cylindrical surface at the bottom. The inner wall of the upper end is provided with threads for connection with the setting tool, and the lower end has a groove extending from the small-diameter cylindrical surface to the large-diameter cylindrical surface. Two symmetrical countersunk holes are provided on the side perpendicular to the groove, and the countersunk holes are provided with threads for connection with guide screws.

[0011] The adapter has a cylindrical structure. Its outer cylindrical surface includes a lower small cylindrical surface and an upper large cylindrical surface. The junction between the small and large cylindrical surfaces is a transition conical surface. Two symmetrical planes are cut into the small cylindrical surface, each with a ball-shaped cavity. A dissolvable ball is placed inside the ball-shaped cavity of the adapter. Two symmetrical guide grooves are provided on the outer cylindrical surface, with the axis of the guide grooves perpendicular to the axis of the ball-shaped cavity. The end of a guide screw is located within one of the guide grooves. The upper inner wall has threads for connection to a setting tool, and the lower inner wall has threads for connection to a pull rod.

[0012] The ball seat has a cylindrical structure. The lower end of its outer surface is conical, with a locking tapered thread at the bottom. From top to bottom, the inner cavity of the ball seat comprises three progressively smaller inner holes: a first inner hole, a second inner hole, and a third inner hole. A step and an inner conical surface are provided between the first and second inner holes, and a sealing tapered surface is provided between the second and third inner holes. The step fits against the lower end face of the push cylinder; the inner conical surface fits against the transition tapered surface of the adapter.

[0013] The slip is a cylindrical structure with a conical hole on the inner wall at the upper end and a conical thread at the lower end of the conical hole. The slip is fitted onto a ball seat, and the conical hole meshes with the conical surface of the ball seat. Multiple axial cuts are evenly intersecting along the upper and lower end faces of the slip, and a circular hole is provided radially from the outer cylindrical surface at the end of each cut.

[0014] The metal seal has a cylindrical structure with a sealing conical surface on the inner surface. It is fitted onto the conical surface of the ball seat and located at the upper end face of the slip.

[0015] During bridge plug setting, the pusher and ball seat move forward axially together, while the adapter, dissolvable ball, metal sealing ring, slips, base, and pull rod remain relatively stationary axially. Driven by the pusher and ball seat, the metal sealing ring and slips expand radially.

[0016] After the metal sealing ring and slips expand radially to a certain size, they fit tightly against the inner wall of the casing, sealing the upper and lower parts of the casing. The casing anchored to the slips bears the pressure from the upper sealing.

[0017] When the pusher, adapter, dissolvable ball, and pull rod are pulled outward along the axis, the dissolvable ball slides out of the hole.

[0018] When fracturing the target layer, the soluble ball sits on the sealing cone surface inside the ball seat.

[0019] The aforementioned tie rod, adapter, pusher sleeve, and guide screw are made of metal. After the bridge plug is set, the tie rod, adapter, pusher sleeve, and guide screw are removed from the well, while the other components remain downhole. The dissolvable ball, propelled by the fracturing fluid, sits on the conical surface of the ball seat, sealing the central channel of the bridge plug and isolating the fracturing section. All components left downhole are made of magnesium-based dissolvable metal and automatically dissolve after fracturing.

[0020] This invention employs a novel central channel structure for the plugging bridge, eliminating the need for the traditional step of inserting a soluble ball at the wellhead after bridge plug setting, thus improving construction efficiency. Furthermore, the setting status of the bridge plug can be verified immediately after setting, enhancing the reliability of the bridge plug installation. Simultaneously, the metal sealing ring has a wide temperature adaptability range and excellent sealing performance; the integrated slips and novel locking structure reduce the number of tool components and shorten the tool's size, facilitating tool insertion. Attached Figure Description

[0021] Figure 1 This is a cross-sectional structural schematic diagram of the present invention;

[0022] Figure 2 This is a schematic diagram of the structure of the present invention;

[0023] Figure 3 This is a three-dimensional view of the pusher of the present invention;

[0024] Figure 4 This is a three-dimensional view of the adapter of the present invention;

[0025] Figure 5 This is a structural view of the ball seat of the present invention.

[0026] Figure 6 This is a three-dimensional view of the locking seat of the present invention.

[0027] Figure 7 This is one of the principle views of the bridge plug setting mechanism of the present invention.

[0028] Figure 8 This is the second diagram illustrating the principle of bridge plug setting in this invention.

[0029] Figure 9 This is a schematic view of the ball-mounted seat of the present invention. Detailed Implementation

[0030] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the invention.

[0031] like Figure 1 and Figure 2As shown, a ball-free metal-sealed dissolvable bridge plug includes a pusher 1, the upper end of which is threadedly connected to a setting tool, and the lower end of which is installed in the inner hole of the upper part of the ball seat 4.

[0032] It also includes a pull rod 7 and an adapter 2, with the pull rod 7 and the adapter 2 located at the axis. The adapter 2, ball seat 4, and slip 6 are sequentially fitted onto the pull rod 7.

[0033] The adapter 2 is located inside the push cylinder 1. The upper end of the adapter 2 is connected to the setting tool, and the lower end is located inside the ball seat 4 and connected to the pull rod 7 by a thread.

[0034] The lower end of the ball seat 4 is sleeved with the slip 6; the base 8 is fitted onto the tail of the pull rod 7 and connected by threads; the dissolvable ball 3 is located inside the lower end of the adapter 2;

[0035] like Figure 3 As shown, the pusher 1 is a cylindrical structure, consisting of a large-diameter cylindrical surface 14 at the upper end and a small-diameter cylindrical surface 15 at the lower end. The inner wall of the upper end is provided with threads for connection with the setting tool, and the lower end has a slot 11 with a width of 30-50mm and a length of 50-160mm. The slot 11 extends from the small-diameter cylindrical surface 15 to the large-diameter cylindrical surface 14. Two symmetrical countersunk holes 12 are provided on the side perpendicular to the slot 11. The countersunk holes 12 are provided with threads and are threaded to the guide screws 19.

[0036] like Figure 4 As shown, the adapter 2 has a cylindrical structure. Its outer cylindrical surface includes a small cylindrical surface 21 at the lower end and a large cylindrical surface 22 at the upper end. The junction of the small cylindrical surface 21 and the large cylindrical surface 22 is a transitional conical surface 23. Two symmetrical planes 24 are cut from the small cylindrical surface 21, and ball holes 25 are provided on the planes 24. A dissolvable ball 3 is installed inside the ball hole 25 of the adapter 2. Two symmetrical guide grooves 26 are provided on the outer cylindrical surface. The axis of the guide grooves 26 is perpendicular to the axis of the ball hole 25, and the end of the guide screw 19 is located within the guide groove 26. The upper inner wall is provided with threads for connection to the setting tool, and the lower inner wall is provided with threads for connection to the pull rod 7.

[0037] like Figure 5 As shown, the ball seat 4 has a cylindrical structure. The lower end of the outer surface of the ball seat 4 is a conical surface 41, and a locking tapered thread 42 with a length of 10-40mm is provided at the lower end of the conical surface 41. From the upper end to the lower end, the inner cavity of the ball seat 4 includes three gradually decreasing diameter inner holes: a first inner hole 43, a second inner hole 44, and a third inner hole 45. A step 46 and an inner conical surface 47 are provided between the first inner hole 43 and the second inner hole 44, and a sealing conical surface 48 is provided between the second inner hole 44 and the third inner hole 45. The step 46 is in contact with the lower end face of the push cylinder 1; the inner conical surface 47 is in contact with the transition conical surface 23 of the conversion joint 2.

[0038] like Figure 6As shown, the slip 6 has a cylindrical structure with a conical hole 61 on the inner wall of its upper end and a conical thread 62 at the lower end of the conical hole 61. The slip 6 is fitted onto the ball seat 4, and the conical hole 61 engages with the conical surface 41 of the ball seat 4. Multiple slits 63 are evenly and intersectingly cut along the axial direction from the upper and lower end faces of the slip 6. Each slit 63 is 5-10 mm away from the end face, and a circular hole 64 is provided radially from the outer cylindrical surface at the end of each slit 63.

[0039] The metal seal 5 has a cylindrical structure with an inner surface that is a sealing conical surface 51. It is fitted onto the conical surface 41 of the ball seat 4 and is located at the upper end face of the slip 6.

[0040] like Figure 7 As shown in one of the schematic diagrams of the bridge plug setting principle of the present invention, the metal sealing ring 5 expands outward to the inner wall of the sleeve 50, and the slip 6 expands outward to the inner wall of the sleeve 50.

[0041] like Figure 8 As shown in the second schematic diagram of the bridge plug setting principle of the present invention, after the bridge plug is set, when the push cylinder 1, the conversion joint 2, the soluble ball 3, and the pull rod 7 are pulled outward along the axial direction, the soluble ball 3 slides out from the ball hole 25.

[0042] like Figure 9 As shown in the schematic diagram of the dissolvable ball seating principle of the present invention, when the setting tool is lifted, liquid is pumped into the wellbore, and the dissolvable ball 3 enters the central hole of the bridge plug along with the liquid. The dissolvable ball 3 falls on the sealing cone surface 48 of the ball seat 4, blocking the central channel of the bridge plug.

Claims

1. A ball-free, metal-sealed, dissolvable bridge plug, characterized in that, Includes a pusher (1), the upper end of which is threadedly connected to the setting tool, and the lower end is installed in the inner hole of the ball seat (4); It also includes a pull rod (7) and an adapter (2), with the pull rod (7) and the adapter (2) located at the axis. The adapter (2), ball seat (4), and slip (6) are sequentially fitted onto the pull rod (7). The adapter (2) is located inside the push cylinder (1). The upper end of the adapter (2) is connected to the setting tool, and the lower end is located inside the ball seat (4) and connected to the pull rod (7) by thread. The pusher (1) is a cylindrical structure, consisting of a large-diameter cylindrical surface (14) at the top and a small-diameter cylindrical surface (15) at the bottom. The inner wall of the upper end is provided with a thread for connection with the setting tool, and the lower end has a slot (11) with a width of 30-50mm and a length of 50-160mm. The slot (11) extends from the small-diameter cylindrical surface (15) to the large-diameter cylindrical surface (14). Two symmetrical countersunk holes (12) are opened on the side perpendicular to the slot (11). The countersunk holes (12) are provided with threads and are threaded to the guide screw (19). The adapter (2) is a cylindrical structure. The outer cylindrical surface includes a small cylindrical surface (21) at the lower end and a large cylindrical surface (22) at the upper end. The connection between the small cylindrical surface (21) and the large cylindrical surface (22) is a transition cone surface (23). The small cylindrical surface (21) is cut into two symmetrical planes (24). A ball hole (25) is provided on the plane (24). The soluble ball (3) is installed in the ball hole (25) of the adapter (2). Two symmetrical guide grooves (26) are provided on the outer cylindrical surface. The axis of the guide groove (26) is perpendicular to the axis of the ball hole (25). The end of the guide screw (19) is located in the guide groove (26). The inner wall of the upper end is provided with a thread for connecting to the setting tool, and the inner wall of the lower end is provided with a thread for connecting to the pull rod (7). The lower end of the ball seat (4) is fitted with the slip (6); the base (8) is fitted onto the tail of the pull rod (7) and connected by threads; the dissolvable ball (3) is located inside the lower end of the adapter (2).

2. The ball-free, soluble metal-sealed bridge plug according to claim 1, characterized in that, The ball seat (4) has a cylindrical structure. The lower end of the outer surface of the ball seat (4) is a conical surface (41). A locking conical thread (42) is provided at the lower end of the conical surface (41). From the upper end to the lower end, the inner cavity of the ball seat (4) includes three gradually decreasing diameter first inner holes (43), second inner holes (44), and third inner holes (45). A step (46) and an inner conical surface (47) are provided between the first inner hole (43) and the second inner hole (44). A sealing conical surface (48) is provided between the second inner hole (44) and the third inner hole (45). The step (46) is in contact with the lower end face of the push cylinder (1). The inner conical surface (47) is in contact with the transition conical surface (23) of the conversion joint (2).

3. The ball-free, soluble metal-sealed bridge plug according to claim 2, characterized in that, The aforementioned slip (6) has a cylindrical structure with a conical hole (61) on the inner wall of the upper end and a conical thread (62) at the lower end of the conical hole (61). The slip (6) is fitted onto the ball seat (4), and the conical hole (61) meshes with the conical surface (41) of the ball seat (4). Multiple cuts (63) are evenly and intersectingly cut along the axial direction from the upper and lower end faces of the slip (6), and a circular hole (64) is provided radially from the outer cylindrical surface at the end of each cut (63).

4. The ball-free, metal-sealed, soluble bridge plug according to claim 3, characterized in that, It also includes a metal seal (5), a cylindrical structure with a sealing conical surface (51) on the inner surface, which is fitted onto the conical surface (41) of the ball seat (4) and located at the upper end face of the slip (6).

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