CN112012692A - High-reliability soluble bridge plug - Google Patents

Abstract

The invention belongs to the technical field of oil field downhole tools, and particularly relates to a high-reliability soluble bridge plug which comprises a mandrel, a rubber cylinder, an upper slip, a lower slip, an upper cone and a lower cone, wherein the mandrel is of a hollow structure, a limiting part is arranged at the lower end of the mandrel, the lower cone, the lower slip, the rubber cylinder, the upper slip and the upper cone are sequentially sleeved on the mandrel from bottom to top, axial extrusion force of the mandrel is applied during setting, the lower slip slides along the lower cone to realize radial expansion and is finally anchored on the inner wall of a casing, the upper slip slides along the upper cone to realize radial expansion and is finally anchored on the inner wall of the casing, the rubber cylinder radially expands and realizes sealing with the casing, and a clamp spring seat is sleeved on the mandrel above the upper cone. The method solves the problem that the soluble bridge plug slides down due to the insecure anchoring of the slip in the well, also solves the problem that the bridge plug needs to wait for the dissolution after fracturing, shortens the waiting time, and improves the anchoring reliability.

Description

A highly reliable soluble bridge plug

technical field

The invention belongs to the technical field of downhole tools in oilfields, and in particular relates to a soluble bridge plug with high reliability.

Background technique

Soluble bridge plugs have been used more and more in the staged fracturing construction of unconventional oil and gas. After the completion of the construction of soluble bridge plugs, no post-processing is required, and there is no residue left in the well. Its structure includes a body, a rubber cylinder and slips, all of which are soluble materials. The soluble bridge plug is set and thrown away by a special setting tool.

The dissolution of the soluble bridge plug begins after it is put into the well. Time control of the soluble bridge plug is the key to ensure that the bridge plug does not dissolve and fail before the fracturing operation is completed. Therefore, the soluble bridge plug inevitably tends to prolong the dissolution time during the manufacture. To avoid early failure, new problems have arisen, and the dissolution time is prolonged, resulting in prolonged dissolution waiting time, which is not conducive to rapid operation. In addition, after the bridge plug is set, the dissolution of slips reduces the reliability of the setting and anchoring, and the bridge plug is prone to slip out after fracturing, which has an adverse effect on the fracturing.

SUMMARY OF THE INVENTION

In order to solve the problem that the dissolution waiting time is too long in the background technology, and the reliability of slip anchoring is reduced due to dissolution, and the bridge plug slips off during fracturing and pressing, the present invention provides a highly reliable soluble bridge plug. Reduced latency and improved anchoring reliability.

The technical scheme provided by the invention is: a highly reliable soluble bridge plug, comprising a mandrel, a rubber cylinder, an upper slip, a lower slip, an upper vertebral body and a lower vertebral body, and the mandrel is a hollow structure , the lower end of the mandrel is provided with a limited part, and the lower vertebral body, the lower slip, the rubber cylinder, the upper slip and the upper vertebral body are sequentially sleeved on the mandrel from bottom to top, and the axial direction of the mandrel is applied when setting. Extrusion force, the lower slip slides along the lower vertebral body to achieve radial expansion and is finally anchored on the inner wall of the casing, the upper slip slides along the upper vertebral body to achieve radial expansion and finally anchors on the inner wall of the casing, the rubber cylinder radially expands expansion and sealing with the casing, the mandrel above the upper vertebral body is sleeved with a circlip seat, the circlip seat abuts against the upper vertebral body, a circlip is installed on the inner side of the circlip seat, and the inner side of the circlip is provided with a retaining tooth, The outer side of the corresponding mandrel is machined with a limit tooth buckle that engages with the clamping teeth. After the engagement of the limit tooth buckle and the clamping teeth, the circlip and the circlip seat are restricted from moving upward relative to the spindle, and a circlip is arranged between the spindle and the circlip seat. There is an unlocking sleeve, the lower end of the unlocking sleeve extends into the upper part of the inner side of the circlip, and the inner side of the circlip has an unlocking cone surface. The upper end of the spring seat is provided with spaced connecting claws along the circumferential direction, and the upper end of the unlocking sleeve is provided with a accommodating groove for accommodating the connecting claws. The connecting claws are connected with the unlocking sleeve through the unlocking scissors. The inner side is processed with a ball seat;

The upper part of the upper vertebral body is a flap-type structure, and an expansion-seal vertebral body is arranged between it and the mandrel. , an annular groove A is machined on the upper part of the inner side of the expansion sealing vertebral body, the mandrel of the corresponding section is machined with spaced long holes along the circumferential direction, the inner side of the mandrel is inserted with a fracturing ball seat sleeve, and the outer side of the fracturing seat sleeve is processed with an annular groove Groove B, the annular groove A is provided with a connecting ring, and the inner side of the connecting ring extends into the annular groove B through the long hole of the mandrel, so that the fracturing ball seat sleeve is linked with the expansion sealing vertebral body. The connecting ring is formed by splicing two half rings.

Further, the inner side of the rubber cylinder is provided with a reinforcing sleeve, the middle part of the reinforcing sleeve is arched, and the arched part is a flap structure, and the reinforcing sleeve and the rubber cylinder are vulcanized into one.

Further, the middle wall of the reinforcing sleeve is thinner than the two ends.

The beneficial effects of the present invention are:

1. After the bridge plug is set, in order to avoid dissolving and making the slip anchoring unreliable, the present invention innovatively designs the upper vertebral body into a flap-type structure. The diameter of the fracturing ball is located at the upper end of the fracturing ball seat sleeve. During fracturing, the pressure acts on the fracturing ball seat sleeve and pushes it downward. At this time, the expansion and sealing vertebral body is linked with it, thereby expanding the upper vertebral body and further. The upper slip will be anchored to ensure the reliability of its anchoring.

2. After fracturing in the present invention, throw a large-diameter pitching ball, and the pitching ball falls on the unlocking sleeve, presses and pushes the unlocking sleeve downward, the unlocking scissors are cut, and the lower end of the unlocking sleeve opens the circlip to release the clamping teeth and the limit tooth buckle. lock, so that the various parts of the bridge plug are disassembled, and the various parts are scattered downhole and slowly dissolved in the well. Therefore, in the present invention, the bridge plug is removed in a simple manner, a full diameter is formed in the wellbore, the waiting time is saved, and the fracturing operation efficiency is improved.

3. The reinforcing sleeve of the present invention can increase the strength of the rubber cylinder, avoid the rubber cylinder from being torn, and ensure the reliability of setting.

Description of drawings

FIG. 1 is a cross-sectional view of the present invention.

FIG. 2 is a cross-sectional view at A-A in FIG. 1 .

Figure 3 is a cross-sectional view of the expanded and sealed vertebral body in the present invention.

Figure 4 is a cross-sectional view of the fracturing ball seat sleeve of the present invention.

FIG. 5 is a partial enlarged view of I in FIG. 1 .

In the picture: 1-limiting part, 2-lower vertebral body, 3-lower slip, 4-plastic cylinder, 5-reinforcing sleeve, 6-upper slip, 7-upper vertebral body, 8-expanding vertebral body, 9- circlip, 10- circlip seat, 11- connecting claw, 12- unlocking scissors, 13- unlocking sleeve, 14- unlocking cone, 15- fracturing ball seat sleeve, 16- connecting ring, 17- long hole , 18 - annular groove A, 19 - annular groove B, 20 - mandrel.

Detailed ways

In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

The present invention includes a mandrel 20 , a rubber cylinder 4 , an upper slip 6 , a lower slip 3 , an upper vertebral body 7 and a lower vertebral body 2 , and the mandrel 20 is a hollow structure. The above are common structures in the prior art, and details are not repeated here.

The main innovation point of the present invention is: the lower end of the mandrel 20 is provided with a limiting portion 1, the lower side of the limiting portion 1 is a tapered surface, and the tapered surface plays the role of guiding shoes, which is more conducive to going downhole. The lower vertebral body 2, the lower slips 3, the rubber cylinder 4, the upper slips 6, and the upper vertebral body 7 are sequentially sleeved on the mandrel 20 from bottom to top, and the axial extrusion force of the mandrel 20 is applied during setting. , the lower slip 3 slides along the lower vertebral body 2 to achieve radial expansion and is finally anchored on the inner wall of the casing, the upper slip 6 slides along the upper vertebral body 7 to achieve radial expansion and is finally anchored on the inner wall of the casing, the rubber cylinder 4 The radial expansion and the sealing with the sleeve are realized, the mandrel 20 above the upper vertebral body 7 is sleeved with a circlip seat 10, the circlip seat 10 abuts against the upper vertebral body 7, and a circlip 9 is installed inside the circlip seat 10 , the inner side of the circlip 9 is provided with a clasp, and the outer side of the corresponding mandrel 20 is processed with a limit tooth buckle that engages with the clasp. The mandrel 20 goes up, an unlocking sleeve 13 is arranged between the mandrel 20 and the circlip seat 10, the lower end of the unlocking sleeve 13 extends into the upper part of the inner side of the circlip 9, the inner side of the circlip 9 has an unlocking cone surface 14, and the unlocking sleeve 13 unlocks along the The conical surface 14 goes down to open the circlip 9 so as to release the locking of the claws and the limit tooth buckle. The upper end of the circlip seat 10 is provided with spaced connecting claws 11 along the circumferential direction, and the upper end of the unlocking sleeve 13 is provided with a connecting claw 11. In the holding groove, the connecting claw 11 is connected with the unlocking sleeve 13 through the unlocking scissors 12, and the upper end of the connecting claw 11 is flush with the upper end surface of the unlocking sleeve 13, so as to prevent the unlocking sleeve 13 from being pushed down by mistake when the setting seal pushes the circlip seat 10 downward. The inner side of the upper end of the unlocking sleeve 13 is processed with a ball seat.

The upper part of the upper vertebral body 7 is a flap-type structure, and between it and the mandrel 20, there is an expansion-seal vertebral body 8, the expansion-seal vertebral body 8 is thick on the upper part and the lower part is thin, and the expansion-seal vertebral body 8 descends to squeeze the upper part of the upper vertebral body 7. The flap structure is expanded outward, the inner upper part of the expansion and sealing vertebral body 8 is processed with an annular groove A18, the mandrel 20 of the corresponding section is processed with spaced long holes 17 in the circumferential direction, and the inner side of the mandrel 20 is inserted with a fracturing ball seat sleeve 15. An annular groove B19 is machined on the outside of the fracturing seat sleeve 15, a connecting ring 16 is provided in the annular groove A18, and the inner side of the connecting ring 16 extends into the annular groove B19 through the long hole 17 of the mandrel 20, thereby The fracturing ball seat sleeve 15 is linked with the expansion and sealing vertebral body 8, and the connecting ring 16 is formed by splicing two half rings.

The inner side of the rubber cylinder 4 is provided with a reinforcing sleeve 5, the middle of the reinforcing sleeve 5 is arched, and the arched part is a petal-type structure, and the petal-type structure can follow the rubber cylinder 4 when the rubber cylinder 4 is axially compressed. 5 and the rubber cylinder 4 are vulcanized into one body, and the reinforcing sleeve 5 can increase the strength of the rubber cylinder 4, avoid the rubber cylinder 4 from being torn, and ensure the reliability of the setting.

The wall of the middle part of the reinforcing sleeve 5 is thinner than that of the two ends, so that the middle part of the reinforcing sleeve 5 is easier to bend.

In the present invention, an axial pressure is applied to it by a special setting tool, and the rubber cylinder 4 is extruded to be set. In the present invention, when fracturing after setting, the fracturing ball is first put into the downhole, and the fracturing ball falls on the upper end of the fracturing ball seat sleeve 15. During fracturing, the pressure acts on the fracturing ball seat sleeve 15 and pushes it downward. , at this time, the expansion and sealing vertebral body 8 is linked with the fracturing ball seat sleeve 15, so as to open the upper vertebral body 7, and further anchor the upper slips 6 to ensure the reliability of its anchoring, and prevent the slips from being dissolved and anchored. Not reliable.

After the fracturing of the present invention is completed, a ball is thrown downhole again, and the diameter of the ball is larger than the diameter of the fracturing ball, so that the head ball falls on the unlocking sleeve 13, presses and pushes the unlocking sleeve 13 downward, the unlocking scissors 12 are cut off, and the unlocking sleeve 13 The lower end stretches the retaining spring 9 to release the locking of the retaining tooth and the limit tooth buckle, so that the various components of the bridge plug are disassembled, and the components are scattered downhole and slowly dissolved in the well. Therefore, in the present invention, the bridge plug is removed in a simple manner, a full diameter is formed in the wellbore, the waiting time is saved, and the fracturing operation efficiency is improved.

In the present invention, the lower vertebral body 2, the lower slip 3, the rubber cylinder 4, the upper slip 6, the upper vertebral body 7, and the circlip seat 10 are not connected to each other. In the present invention, each component is disassembled, so that it can easily fall into the well and realize the full diameter of the well.

Claims (3)

1. The utility model provides a soluble bridge plug that reliability is high, includes mandrel (20), packing element (4), goes up slips (6), slips (3) down, goes up centrum (7) and lower centrum (2), mandrel (20) be hollow structure, its characterized in that: the lower end of the mandrel (20) is provided with a limiting part (1), the lower cone (2), the lower slip (3), the rubber cylinder (4), the upper slip (6) and the upper cone (7) are sequentially sleeved on the mandrel (20) from bottom to top, axial extrusion force of the mandrel (20) is applied during setting, the lower slip (3) slides along the lower cone (2) to realize radial expansion and is finally anchored on the inner wall of the casing, the upper slip (6) slides along the upper cone (7) to realize radial expansion and is finally anchored on the inner wall of the casing, the rubber cylinder (4) radially expands and realizes sealing with the casing, the mandrel (20) above the upper cone (7) is sleeved with a clamp spring seat (10), the clamp spring seat (10) is abutted against the upper cone (7), a clamp spring (9) is installed on the inner side of the clamp spring seat (10), clamp teeth are arranged on the inner side of the clamp spring (9), and limiting tooth buckles meshed with the clamp teeth are processed on the outer side of the corresponding mandrel (20, after the limiting tooth buckles are meshed with the clamping teeth, the clamp spring (9) and the clamp spring seat (10) are limited to move upwards relative to the mandrel (20), an unlocking sleeve (13) is arranged between the mandrel (20) and the clamp spring seat (10), the lower end of the unlocking sleeve (13) extends into the upper portion of the inner side of the clamp spring (9), an unlocking conical surface (14) is arranged on the inner side of the clamp spring (9), the unlocking sleeve (13) moves downwards along the unlocking conical surface (14) to unfold the clamp spring (9) so as to unlock the clamping teeth and the limiting tooth buckles, the upper end of the clamp spring seat (10) is circumferentially provided with spaced connecting claws (11), a containing groove for containing the connecting claws (11) is formed in the upper end of the unlocking sleeve (13), the connecting claws (11) are connected with the unlocking sleeve (13) through unlocking shear pins (12), the upper end of the connecting claws (11) is flush with the upper end surface of the unlocking sleeve (13), and a ball seat is machined in the inner side of;

the upper part of the upper vertebral body (7) is of a petal type structure, an expansion sealing vertebral body (8) is arranged between the upper vertebral body and a mandrel (20), the expansion sealing vertebral body (8) is thick at the upper part and thin at the lower part, the expansion sealing vertebral body (8) extrudes downwards to expand the petal type structure at the upper part of the upper vertebral body (7), an annular groove A (18) is processed at the upper part of the inner side of the expansion sealing vertebral body (8), slotted holes (17) are machined at intervals along the circumferential direction of a mandrel (20) at the corresponding section, a fracturing ball seat sleeve (15) is inserted into the inner side of the mandrel (20), an annular groove B (19) is machined on the outer side of the fracturing seat sleeve (15), a connecting ring (16) is arranged in the annular groove A (18), the inner side of the connecting ring (16) penetrates through the slotted holes (17) of the mandrel (20) and extends into the annular groove B (19), thereby make fracturing ball seat cover (15) and the linkage of bloated centrum (8), go up the link (16) and form by two semi-ring concatenation.

2. A highly reliable soluble bridge plug according to claim 1, wherein: the rubber sleeve (4) is internally provided with a reinforcing sleeve (5), the middle part of the reinforcing sleeve (5) is arched, the arched part is of a petal type structure, and the reinforcing sleeve (5) and the rubber sleeve (4) are vulcanized into a whole.

3. A highly reliable soluble bridge plug according to claim 2, wherein: the wall of the middle part of the reinforcing sleeve (5) is thinner than that of the two ends.

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