Soluble bridge plug for oil and gas well fracturing

Abstract

The utility model discloses a soluble bridge plug for oil and gas well fracturing, which relates to the technical field of oil and gas well fracturing and comprises a soluble ball, a rubber sleeve, two compression ring components, a wedge-shaped body, a slip, a ball seat, a body pipe, an elastic pipe and a front seat. The top of the ball seat is open, a step is arranged on the inner wall of the ball seat and used for clamping a soluble ball, the outer wall of the bottom end of the ball seat is in threaded connection with the body pipe, the body pipe is sequentially sleeved with the pressing ring assembly, the rubber sleeve, the pressing ring assembly, the wedge-shaped body, the slip and the elastic pipe with the ball seat as the starting point, and the wedge-shaped body is fixed to the body pipe through a plurality of first shear pins arrayed in the circumferential direction. The outer wall of the wedge-shaped body is matched with the inner wall of the slip through a slope, the elastic pipe is fixed to the body pipe through a plurality of second shear pins arranged in the circumferential direction, the front base is in threaded connection to the bottom of the body pipe, a plurality of elastic pieces are arranged on the outer wall of the elastic pipe in the circumferential direction, and the bottom ends of the elastic pieces are of acute-angle structures while the top ends of the elastic pieces are of obtuse-angle structures. The two sides of the elastic piece are each provided with a strip-shaped groove penetrating through the elastic pipe. According to the scheme, the sealing performance and the pressure bearing capacity are greatly improved.

Description

Technical Field

[0001] The utility model relates to the technical field of oil and gas well fracturing, in particular to a soluble bridge plug used for oil and gas well fracturing. Background Art

[0002] Multi-layer staged fracturing is a commonly used technique in oil and gas well fracturing operations. The principle is as follows: a soluble bridge plug is dropped into the wellbore and stuck in the corresponding sliding sleeve to form a sealed area to isolate different fracturing sections so that fracturing operations can be carried out within the area; after fracturing is completed, the soluble bridge plug dissolves under specific conditions (such as temperature, pressure or chemical reaction).

[0003] The key to successful fracturing is related to the sealing and pressure-bearing capacity of the soluble bridge plug. For example, CN114482957 B discloses an open-hole full-diameter infinite-stage segmented fracturing completion device and a fracturing completion method thereof. This solution only uses a second seal to seal the opening tool and the sleeve. After the opening tool is dropped into the wellbore, the second seal will be worn out for a well section of 4000-6000 meters long. After reaching the target layer, the second seal cannot perform the sealing function. This solution enables the opening slider to be stuck in the opening groove, thereby causing the opening tool to be stuck in the corresponding sleeve. However, the cross-sectional shapes of the opening slider and the opening groove are both trapezoidal, and the pressure-bearing capacity is small. Utility Model Content

[0004] In order to solve the deficiencies of the existing technology, the utility model provides a soluble bridge plug for oil and gas well fracturing, which improves the sealing performance and pressure bearing capacity.

[0005] In order to achieve the purpose of this utility model, the following scheme is proposed:

[0006] A soluble bridge plug for oil and gas well fracturing comprises a soluble ball, a rubber cylinder, two pressure ring components, a wedge, slips, a ball seat, a body tube, an elastic tube and a front seat.

[0007] The top of the ball seat is open, and its inner wall is provided with a step for clamping the soluble ball. The outer wall of the bottom end of the ball seat is threadedly connected to the main body tube. Starting from the ball seat, the pressure ring assembly, rubber cylinder, pressure ring assembly, wedge body, slips, and elastic tube are sequentially sleeved on the outside of the main body tube. The wedge body is fixed to the main body tube through a circumferential array of multiple first shear pins. The outer wall of the wedge body and the inner wall of the slip are adapted to each other through an inclined surface. The elastic tube is fixed to the main body tube through a circumferential array of multiple second shear pins. The front seat is threadedly connected to the bottom of the main body tube. There are multiple elastic sheets in the circumferential array on the outer wall of the elastic tube. The bottom end of the elastic sheet is an acute-angle structure and the top end is an obtuse-angle structure. A strip groove running through the elastic tube is provided on each side of the elastic sheet.

[0008] Furthermore, a plurality of straightening plates are arrayed along the circumferential direction on the outer wall of the elastic tube. The number and position of the straightening plates correspond one to one with the elastic plates. The straightening plates are located between the elastic plates and the front seat. The bottom and top ends of the straightening plates are both obtuse-angle structures. The bottom end of the strip groove is located between the straightening plates and the front seat. The outer diameter of the straightening plates is larger than the outer diameter of the elastic plates.

[0009] Furthermore, the area between the ball seat, the wedge-shaped body and the outer wall of the main body tube constitutes a groove, and the two pressure ring assemblies are symmetrically arranged in the groove. The pressure ring assemblies include a first ring, a second ring, a third ring and a fourth ring in sequence. For the upper pressure ring assembly, the first ring is adapted to the ball seat through an inclined surface, the first ring is adapted to the second ring through a step, the second ring is adapted to the third ring through an inclined surface, and the fourth ring is adapted to the rubber cylinder through a step.

[0010] Furthermore, a circle of trapezoidal grooves is provided on the inner wall of the rubber cylinder, a sealing sleeve and a sealing ring are provided in the trapezoidal groove, and the sealing ring is located on the inner side of the sealing sleeve.

[0011] Furthermore, the outer wall of the slip is provided with two circles of inlaid columns, and corresponding positions at both ends of the slip are provided with cutouts.

[0012] The beneficial effects of the present invention are:

[0013] 1. By squeezing the rubber sleeve, the rubber of the rubber sleeve expands and fits tightly against the inner wall of the sleeve, achieving effective sealing. The soluble bridge plug has a pressure-bearing level of 70MPa and withstands pressure in two ways: first, the elastic sheet bears pressure, and the bottom end of the elastic sheet is inserted downward into the slot, which improves the pressure-bearing capacity; second, the slips open and clamp the inner wall of the sleeve, which also plays a role in bearing pressure.

[0014] 2. The elastic piece of each soluble bridge plug is of different length. The soluble bridge plugs are placed into the wellbore in a certain order to ensure that the soluble bridge plugs are stuck in the sliding sleeve at a specific position, thereby improving accuracy.

[0015] 3. The soluble bridge plug is made of soluble material. After the fracturing is completed, the soluble bridge plug will be dissolved, so that the diameter inside the sliding sleeve can still be maintained, which is convenient for subsequent well repair operations.

[0016] 4. The elastic sheet soluble bridge plug is easy to operate and highly reliable. The soluble bridge plug can be directly put into the wellbore without the assistance of other equipment, which greatly saves costs.

[0017] 5. The soluble bridge plug is a purely mechanical structure without any electronic components. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The external structure of the soluble bridge plug is shown;

[0019] Figure 2 A cross-sectional view of a dissolvable bridge plug is shown;

[0020] Figure 3 for Figure 2 A partial enlarged view of the middle part;

[0021] Figure 4 for Figure 2 A partial enlarged view of point B in the middle. DETAILED DESCRIPTION

[0022] like Figure 1 、 Figure 2 As shown, this embodiment provides a soluble bridge plug for oil and gas well fracturing, including a soluble ball 51, a rubber cylinder 52, two pressure ring assemblies 3, a wedge 53, slips 54, a ball seat 55, a body tube 56, an elastic tube 57, and a front seat 58.

[0023] Specifically, the top of the ball seat 55 is open, and the inner wall of the ball seat 55 is provided with a step for clamping the soluble ball 51. The outer wall of the bottom end of the ball seat 55 is threadedly connected to the main body tube 56. Starting from the ball seat 55, the pressure ring assembly 3, the rubber cylinder 52, the pressure ring assembly 3, the wedge 53, the slip 54, and the elastic tube 57 are sequentially sleeved outside the main body tube 56. Figure 3 As shown, the inner wall of the rubber cylinder 52 is provided with a circle of trapezoidal grooves, and a sealing sleeve 521 and a sealing ring are provided in the trapezoidal groove. The sealing ring is located inside the sealing sleeve 521, as shown in FIG. Figure 1 、 Figure 4 As shown, the wedge 53 is fixed to the main body tube 56 by a plurality of first shear pins 21 arranged in a circumferential pattern, and the outer wall of the wedge 53 is adapted to the inner wall of the slip 54 by an inclined surface, as shown in FIG. Figure 1 、 Figure 2 As shown, the elastic tube 57 is fixed to the main body tube 56 by a plurality of second shear pins 22 in a circumferential array, and the front seat 58 is threadedly connected to the bottom of the main body tube 56. The outer wall of the elastic tube 57 has a plurality of elastic sheets 571 in a circumferential array. The outer wall of the elastic sheet 571 is arc-shaped, and the center of the arc is located on the central axis of the elastic tube 57. The bottom end of the elastic sheet 571 is an acute-angle structure and the top end is an obtuse-angle structure. A strip groove 572 is provided on each side of the elastic sheet 571 and passes through the elastic tube 57. The function of the strip groove 572 is to enable the elastic tube 57 to be elastically deformed.

[0024] To smoothly engage the soluble bridge plugs within their corresponding sleeves, a groove is provided on the inner wall of the sleeve. The groove's shape matches that of the elastic sheet 571, and its bottom end also forms an acute angle. The length of the groove on each sleeve increases gradually from the wellhead to the bottom. Therefore, when deploying the soluble bridge plugs into the wellbore, the one with the longest elastic sheet 571 is deployed first, followed by those with progressively shorter elastic sheets 571, ensuring that the soluble bridge plugs are engaged within their corresponding sleeves.

[0025] The sealing principle is as follows:

[0026] After the soluble bridge plug is clamped in the corresponding sliding sleeve, pressure is applied to the soluble bridge plug, and the elastic sheet 571 is tightly clamped in the clamping groove. The soluble ball 51, the ball seat 55, the main body tube 56, the rubber cylinder 52, the two pressure ring assemblies 3, and the wedge body 53 move downward as a whole. The second shear pin 22 of the elastic tube 57 is sheared off by the force, and the first shear pin 21 of the wedge body 53 is sheared off by the force. In this process, the tip of the bottom of the wedge body 53 squeezes the slip 54, causing the slip 54 to open and clamp the inner wall of the sliding sleeve. The two pressure ring assemblies 3 will squeeze the rubber cylinder 52, causing the rubber of the rubber cylinder 52 to expand and fit tightly against the inner wall of the sliding sleeve to achieve sealing.

[0027] The pressure conditions are as follows:

[0028] First, the pressure is borne by the elastic sheet 571 , and the bottom end of the elastic sheet 571 is inserted downward into the card slot 141 , thereby improving the pressure bearing capacity; second, the slips 54 are opened and clamped to the inner wall of the sliding sleeve, which can also play a role in bearing pressure.

[0029] When the soluble bridge plug is put into the wellbore, the elastic sheet 571 is in a compressed state when entering the well. In order to ensure that the soluble bridge plug enters the well smoothly and reaches the sliding sleeve at a specific position, the present embodiment adopts the following measures: Figure 1 、 Figure 2 As shown, the outer wall of the elastic tube 57 is also arrayed with a plurality of straightening pieces 573 along the circumferential direction. The number and position of the straightening pieces 573 correspond to the elastic pieces 571 one by one. The outer diameter of the straightening piece 573 is larger than the outer diameter of the elastic piece 571. The straightening piece 573 is located between the elastic piece 571 and the front seat 58. The bottom and top ends of the straightening piece 573 are both obtuse-angled structures. The bottom end of the strip groove 572 is located between the straightening piece 573 and the front seat 58. A circle of avoidance grooves is provided on the inner wall of the sliding sleeve. When the soluble bridge plug is stuck in the corresponding slot, the straightening piece 573 is located in the avoidance groove.

[0030] Because the outer diameter of the straightening piece 573 is slightly larger than the outer diameter of the elastic piece 571, when the soluble bridge plug enters the small inner diameter space from the large inner diameter of the sliding sleeve, the straightening piece 573 will be compressed, and the straightening piece 573 will drive the elastic piece 571 to be compressed as a whole, ensuring that the entire soluble bridge plug will not get stuck when entering the small inner diameter, and further ensuring that it will get stuck only within a specific length of the slot.

[0031] The specific structure of the pressure ring assembly 3 is as follows: Figure 2 、 Figure 3As shown, the area between the ball seat 55, the wedge-shaped body 53 and the outer wall of the main body tube 56 constitutes a groove, and the two pressure ring assemblies 3 are symmetrically arranged in the groove. The pressure ring assembly 3 includes a first ring 31, a second ring 32, a third ring 33 and a fourth ring 34 in sequence. For the upper pressure ring assembly 3, its first ring 31 is adapted to the ball seat 55 through an inclined surface, the first ring 31 is adapted to the second ring 32 through a step, the second ring 32 and the third ring 33 are adapted through an inclined surface, and the fourth ring 34 is adapted to the rubber cylinder 52 through a step. For the lower pressure ring assembly 3, its first ring 31 is adapted to the wedge-shaped body 53 through an inclined surface. The cross-sectional shape of the fourth ring 34 can be rectangular or L-shaped.

[0032] The specific structure of slips 54 is as follows: Figure 1 As shown, the outer wall of the slip 54 is provided with two circles of inlaid columns 541, and the corresponding positions of the upper and lower ends of the slip 54 are provided with cutouts 542. The function of the cutouts 542 is to ensure that when the tip of the bottom of the wedge-shaped body 53 squeezes the slip 54, the slip 54 can be smoothly opened and clamped to the inner wall of the sliding sleeve.

[0033] The soluble bridge plug provided in this embodiment has the following performance advantages:

[0034] ①Adapt to different temperature ranges of 38℃~178℃ (100F-350F);

[0035] ② A variety of material combination designs can be provided to meet the requirements of different blocks;

[0036] ③ Pressure level 70MPa (10000PSI), integrated anti-premature setting design, capable of setting in a specific position of the sleeve;

[0037] ④100% metal soluble materials, such as magnesium-aluminum alloy, are completely dissolved within 5 days (the dissolution time can be adjusted according to site needs);

[0038] ⑤ Fine treatment of metal surface, surface coating treatment, acid-resistant, water-soluble, anti-corrosion surface spraying to adapt to the construction wells of acid injection immersion;

[0039] ⑥Applicable to all current casing steel grades (P110 / 125 / 140, etc.);

[0040] ⑦ The maximum inner diameter design is conducive to flowback after fracturing without affecting production.

[0041] The above embodiments are only used to illustrate the technical ideas and features of the present invention and are not intended to be exclusive or limitative of the present invention. It should be understood by those skilled in the art that various changes or equivalent replacements made to the present invention without departing from the scope of the present invention are within the scope of protection of the present invention.

Claims

1. A soluble bridge plug for oil and gas well fracturing, characterized in that: It includes a soluble ball (51), a rubber cylinder (52), two pressure ring assemblies (3), a wedge (53), a slip (54), a ball seat (55), a body tube (56), an elastic tube (57), and a front seat (58); The top of the ball seat (55) is open, and its inner wall is provided with a step for clamping the soluble ball (51). The outer wall of the bottom end of the ball seat (55) is threadedly connected to the body tube (56); Starting from the ball seat (55), the first pressure ring assembly (3), the rubber cylinder (52), the second pressure ring assembly (3), the wedge body (53), the slips (54), and the elastic tube (57) are sequentially sleeved on the outside of the main body tube (56); the wedge body (53) is fixed to the main body tube (56) through a plurality of first shear pins (21) in a circumferential array; the outer wall of the wedge body (53) and the inner wall of the slips (54) are adapted to each other through an inclined surface; the elastic tube (57) is fixed to the main body tube (56) through a plurality of second shear pins (22) in a circumferential array; and the front seat (58) is threadedly connected to the bottom of the main body tube (56); The outer wall of the elastic tube (57) is provided with a plurality of elastic sheets (571) in a circumferential array. The bottom end of the elastic sheet (571) is an acute-angle structure, and the top end is an obtuse-angle structure. A strip groove (572) penetrating the elastic tube (57) is provided on each side of the elastic sheet (571).

2. The soluble bridge plug for oil and gas well fracturing according to claim 1, characterized in that: The outer wall of the elastic tube (57) is also arrayed with a plurality of straightening pieces (573) along the circumferential direction. The number and position of the straightening pieces (573) and the elastic pieces (571) correspond one to one. The straightening piece (573) is located between the elastic piece (571) and the front seat (58). The bottom and top ends of the straightening piece (573) are both obtuse-angled structures. The bottom end of the strip groove (572) is located between the straightening piece (573) and the front seat (58). The outer diameter of the straightening piece (573) is larger than the outer diameter of the elastic piece (571).

3. The soluble bridge plug for oil and gas well fracturing according to claim 1, characterized in that: The area between the ball seat (55), the wedge-shaped body (53) and the outer wall of the main body tube (56) forms a groove, and the two pressure ring assemblies (3) are symmetrically arranged in the groove. The pressure ring assemblies (3) sequentially include a first ring (31), a second ring (32), a third ring (33) and a fourth ring (34). For the upper pressure ring assembly (3), the first ring (31) is adapted to the ball seat (55) through an inclined surface, the first ring (31) is adapted to the second ring (32) through a step, the second ring (32) is adapted to the third ring (33) through an inclined surface, and the fourth ring (34) is adapted to the rubber cylinder (52) through a step.

4. The soluble bridge plug for oil and gas well fracturing according to claim 1, characterized in that: The inner wall of the rubber cylinder (52) is provided with a circle of trapezoidal grooves, and a sealing sleeve (521) and a sealing ring are provided in the trapezoidal groove, and the sealing ring is located on the inner side of the sealing sleeve (521).

5. The soluble bridge plug for oil and gas well fracturing according to claim 1, characterized in that: The outer wall of the slip (54) is provided with two circles of inlaid columns (541), and corresponding positions at both ends of the slip (54) are provided with cutouts (542).

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