CN113389518A

CN113389518A - Soluble bridge plug and interlayer plugging system

Info

Publication number: CN113389518A
Application number: CN202110667166.9A
Authority: CN
Inventors: 朱雯雯; 马东
Original assignee: Jiangsu Unconventional Energy Technology Development Co ltd
Current assignee: Jiangsu Unconventional Energy Technology Development Co ltd
Priority date: 2021-06-16
Filing date: 2021-06-16
Publication date: 2021-09-14

Abstract

The invention discloses a soluble bridge plug and an interlayer plugging system, and relates to the technical field of unconventional oil and gas exploitation. So set up, the flowback ball of previous interval takes a seat at the concave position, and flowback well fluid flows into in the concave position reentrant through-hole through the fluting on flowback ball next door, has solved soluble bridging plug among the prior art and has easily appeared the shutoff ball and hinder the flowback, even with the problem of flowback passageway jam.

Description

Soluble bridge plug and interlayer plugging system

Technical Field

The invention relates to the technical field of unconventional oil and gas exploitation, in particular to a soluble bridge plug and an interlayer plugging system.

Background

The exploitation of unconventional oil and gas such as shale gas, shale oil, coal bed gas, tight sandstone gas and the like usually needs volume fracturing with large displacement to reform a formation seepage channel. The bridge plug is a mature sectional tool in fracturing engineering and is suitable for use in casing.

At present, bridge plugs are mainly divided into composite drillable bridge plugs, cast iron large-drift-diameter drilling-free bridge plugs, soluble bridge plugs and the like. After fracturing of the composite drillable bridge plug is completed, the composite drillable bridge plug can be drilled by using the coiled tubing with a drill bit, and an oil-gas production channel of a full-bore shaft is recovered, but the construction risk and the operation cost for drilling and removing the bridge plug by using the coiled tubing are higher; the cast iron large-drift-diameter drilling-free bridge plug is difficult to drill and remove, and a full-drift-diameter shaft is difficult to recover after fracturing, so that the operation of later-stage production logging and the like is influenced. The soluble bridge plug can react with the water solution in the well to be dissolved after fracturing is completed, a full-drift-diameter shaft is recovered, and great performance superiority is embodied along with the increase of the exploitation depth of unconventional oil gas; however, during blowout flowback, flowback well fluid flows toward the wellhead, and before the soluble bridge plug is dissolved, the plugging ball of the previous interval can generate a large blocking effect on the flow of the flowback well fluid, even block a flowback channel, and cause flowback unsmooth.

Therefore, how to solve the problem that the soluble bridge plug in the prior art is easy to have a blocking ball to block the backflow and even block the backflow channel becomes an important technical problem to be solved by the technical personnel in the field.

Disclosure of Invention

The invention aims to provide a soluble bridge plug to solve the problems that a plugging ball of a previous interval in the prior art has large resistance to blowout and flowback and even can block a flowback channel. The technical effects that can be produced by the preferred technical scheme in the technical schemes provided by the invention are described in detail in the following.

In order to achieve the purpose, the invention provides the following technical scheme:

the invention provides a soluble bridge plug which comprises a cone, a slip and a guide shoe which are sequentially connected, wherein a sealing mechanism is arranged at the junction of the outer wall of the cone and the slip, through holes which extend along the axial direction and are mutually communicated are formed in the cone, the slip and the guide shoe, a concave position for a backflow ball to sit and a groove for backflow well liquid to flow through are formed in one end, away from the slip, of the guide shoe, the groove, the concave position and the through holes are communicated, and the backflow well liquid sequentially flows through the groove and the concave position and flows into the through holes.

Preferably, the at least two slots are uniformly distributed along the circumferential direction of the guide shoe, and each slot extends along the radial direction of the guide shoe.

Preferably, the end surface of one end of the guide shoe, which is far away from the slip, is in transition connection with the peripheral side wall of the guide shoe through a cambered surface.

Preferably, sealing mechanism establishes including the cover expansion ring and the sealing washer of the outer wall of cone, the periphery wall of expansion ring is equipped with the ring channel, the sealing washer sets up in the ring channel.

Preferably, a plurality of slip teeth are embedded on the slip, and an included angle between the axial direction of the slip teeth and the axial direction of the slip is less than 90 degrees; the end part of the slip is provided with a convex block protruding along the axial direction, the end part of the guide shoe is provided with a groove sinking along the axial direction, and the convex block extends into the groove.

Preferably, the outer surface of the cone close to one end of the guide shoe is provided with external meshing teeth, and the inner surface of the slip is provided with internal meshing teeth meshed with the external meshing teeth.

Preferably, a plurality of wear-resistant particles are embedded on the peripheral side wall of the guide shoe.

The invention also provides an interlayer plugging system which comprises the soluble bridge plug, a setting tool and a setting adapter, wherein the soluble bridge plug is the soluble bridge plug.

Preferably, the setting adapter comprises a setting rod arranged in the through hole in a penetrating mode and a setting barrel connected with one end, far away from the slip, of the cone, one end of the setting rod penetrates through the setting barrel to be connected with the setting tool, and the other end of the setting rod is connected with the guide shoe.

Preferably, the inner wall of the guide shoe is provided with a convex ring protruding towards the direction of the central shaft, the outer wall of the setting rod is provided with a step structure matched with the convex ring, one side of the convex ring, which is far away from the slip, is further provided with a shearing ring, and the shearing ring is in threaded connection with the setting rod.

According to the technical scheme, the soluble bridge plug comprises a cone, a slip, a guide shoe and a sealing mechanism, wherein one end, with a smaller cross section, of the cone extends into the slip, the guide shoe is arranged at one end, with the smaller cross section, of the cone and connected with the end portion of the slip, the sealing mechanism is arranged at the junction position of the outer wall of the cone and the slip, through holes which are axially communicated are formed in the cone, the slip and the guide shoe, a concave position for seating a return ball is formed in one end, away from the slip, of the guide shoe, a notch for flowing through of return well fluid is further formed in one end, away from the slip, of the guide shoe, the notch, the concave position and the through holes are communicated, and when blowout and return are carried out, the return well fluid flows through the notch into the concave position and then flows into the through holes, so that the return well fluid flows towards the direction of a wellhead. So set up, when blowout flowback, the flowback ball takes a seat in concave position department, the flowback ball has fixed position, make it littleer to the resistance of flowback well liquid, simultaneously for a route of the flow design of flowback well liquid, flowback well liquid can not directly flow in the through-hole, but can walk around the flowback ball through in the fluting gets into concave position and flows in the through-hole again, the blowback ball does not influence the blowout flowback of well liquid, the shutoff ball of having solved among the prior art previous interval is big to blowout flowback resistance, perhaps even with the problem of flowback channel blocking up.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic structural view of a soluble bridge plug in an embodiment of the present invention;

FIG. 2 is an exploded view of a soluble bridge plug in an embodiment of the present invention;

fig. 3 is a schematic structural diagram of an interlayer plugging system in an embodiment of the present invention.

In the figure:

1-cone, 2-slip, 3-guide shoe, 301-convex ring, 4-sealing mechanism, 401-expansion ring, 402-sealing ring, 5-through hole, 6-concave position, 7-groove, 8-slip tooth, 9-convex block, 10-groove, 11-external engaged tooth, 12-internal engaged tooth, 13-anti-abrasion particle, 14-setting rod, 141-step structure, 15-setting cylinder, 16-shearing ring, 17-shearing limiter and 18-sealing ball.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the examples given herein without any inventive step, are within the scope of the present invention.

The purpose of this embodiment is to provide a soluble bridge plug to solve the problem that the blocking ball in the previous interval in the prior art has large resistance to blowout and flowback, and may even block the flowback channel.

Hereinafter, embodiments will be described with reference to the drawings. The embodiments described below do not limit the contents of the invention described in the claims. The entire contents of the configurations shown in the following embodiments are not limited to those required as solutions of the inventions described in the claims.

Referring to fig. 1-2, in the present embodiment, the soluble bridge plug includes a cone 1, slips 2, a guide shoe 3, and a sealing mechanism 4, wherein the smaller cross-section end of the cone 1 extends into the slips 2, the guide shoe 3 is disposed at the smaller cross-section end of the cone 1, and the guide shoe 3 is connected to the end of the slips 2, a sealing mechanism 4 is arranged at the junction position of the outer wall of the cone 1 and the slips 2, through holes 5 which are axially communicated are arranged in the cone 1, the slips 2 and the guide shoe 3, a concave position 6 for seating a return ball is arranged at one end of the guide shoe 3 far away from the slips 2, and one end of the guide shoe 3 far away from the slip 2 is also provided with a slot 7 for the flow of the flow-back well fluid, the slot 7, the concave position 6 and the through hole 5 are communicated, when blowout flowback is carried out, flowback well fluid flows through the open groove 7, enters the concave position 6 and then flows into the through hole 5, so that the flowback well fluid flows towards the direction of a wellhead.

So set up, when blowout flowback, the ball of returning takes a seat in concave position 6 department, it has fixed position to return the ball, make it littleer to the resistance of returning the flowing well liquid, simultaneously for a route of the flow design of returning the flowing well liquid, it can get into concave position 6 through the fluting 7 on returning the ball next door and flow into in the through-hole 5 again to return the flowing well liquid, it does not influence the blowout flowback of well liquid to return the ball, the shutoff ball 18 of having solved among the prior art previous interval is big to the blowout flowback resistance, perhaps even with the problem of flowback channel jam.

In a specific embodiment, the recess 6 has a cylindrical spatial shape, which is arranged coaxially with the through hole 5, and the radius of the recess 6 is smaller than the radius of the blocking ball 18. The depth of the slot 7 is greater than the maximum height of the blocking ball 18 in the recess 6, and the depth of the slot 7 refers to the height of the slot 7 in the axial direction of the guide shoe 3. With this arrangement, when the sealing ball 18 is seated in the pocket 6, the sealing ball 18 does not seal the passage between the groove 7 and the pocket 6, and the groove 7 and the pocket 6 are ensured to communicate with each other.

In a preferred scheme of the embodiment, one end of the guide shoe 3, which is far away from the slip 2, is provided with at least two slots 7, each slot 7 is uniformly distributed along the circumferential direction of the guide shoe 3, each slot 7 extends along the radial direction of the guide shoe 3, and the slots 7 penetrate between the circumferential side wall of the guide shoe 3 and the concave position 6.

So set up, each fluting 7 all can supply the well fluid of blowout flowback to flow through for soluble bridging plug is less to the flow hindrance of flowback well fluid.

In the embodiment, the end surface of the end of the guide shoe 3 far away from the slip 2 is in transition connection with the peripheral side wall of the guide shoe 3 through a cambered surface. So set up, be convenient for soluble bridging plug to descend in the sleeve, reduce the risk that soluble bridging plug meets the card in danger.

In a preferred embodiment of the present embodiment, the sealing mechanism 4 includes an expansion ring 401 and a sealing ring 402, the expansion ring 401 is sleeved on the outer wall of the cone 1, an annular groove is formed on the outer peripheral wall of the expansion ring 401, and the sealing ring 402 is disposed in the annular groove. The angle formed by the inner surface of the expansion ring 401 and the axial direction and the angle formed by the outer surface of the cone 1 and the axial direction can improve the sealing effect of the sealing mechanism 4. The material of the expansion ring 401 may be, but is not limited to, soluble metals, such as magnesium aluminum alloy; the material of the sealing ring 402 may be, but is not limited to, soluble rubber. The sealing mechanism 4 in this embodiment has a simple structure and dissolves more quickly.

In the embodiment, a plurality of slip teeth 8 are embedded on the slip 2, and the included angle between the axial direction of the slip teeth 8 and the axial direction of the slip 2 is less than 90 degrees, specifically, the included angle between the axial direction of the slip teeth 8 and the axial direction of the slip 2 can be set to 75-80 degrees, so that the slip teeth 8 can be anchored on a casing well. The tip of slips 2 one end that is close to guide shoe 3 is equipped with along a plurality of lugs 9 of axial bulge, and the tip of guide shoe 3 one end that is close to slips 2 is equipped with along a plurality of recesses 10 of axial sunken, and each lug 9 and each recess 10 interval respectively set up for lug 9 stretches into in recess 10 just, so, realizes being connected between slips 2 and the guide shoe 3.

In a preferred version of this embodiment, the outer surface of the cone 1 near the end of the guide shoe 3 is provided with external teeth 11 and the inner surface of the slip 2 is provided with internal teeth 12 which mesh with the external teeth 11. After the soluble bridge plug is seated, the external engagement teeth 11 and the internal engagement teeth 12 are engaged and connected, so that the contact slip resistance of the cone 1 and the slip 2 is increased, the cone 1 is difficult to slip from the slip 2, the slip 2 is anchored more stably, and the construction reliability of the soluble bridge plug is improved.

In this embodiment, a plurality of wear-resistant particles 13 are embedded on the peripheral side wall of the guide shoe 3 to increase the friction between the guide shoe 3 and the inner wall of the casing. So set up for the connection between soluble bridge plug and the sleeve pipe is more reliable and more stable after the setting.

The soluble bridge plug is made of soluble materials, the cone 1, the slips 2 and the guide shoe 3 can be made of soluble magnesium-aluminum alloy, but are not limited to being made of soluble magnesium-aluminum alloy, the blocking ball 18 is a super clean water soluble ball, is suitable for the temperature range of 25-250 ℃, has no requirement on the mineralization degree of well fluid, can be dissolved in clean water, active water, fracturing fluid, formation water and other liquids automatically, can be dissolved quickly after fracturing is completed, a blowout and flowback channel is unblocked, the well fluid is exchanged quickly to accelerate the complete dissolution of the soluble bridge plug, and at least half of time is saved for the full path.

Moreover, the length range of the slips 2 of the soluble bridge plug provided by the application is 70mm-120mm, the angle range between the outer surface of the cone 1 and the axial direction is 5-18 degrees, compared with the traditional soluble bridge plug, the slips 2 in the application are longer, the taper of the cone 1 is smaller, the slips can be smoothly put into the well even if the casing is deformed, the trafficability in the well is good, and the problem that the slips cannot be set on the casing is avoided.

In a specific setting process, the cone 1 and the slip 2 are subjected to reverse extrusion acting force in the axial direction, so that the sealing mechanism 4 and the slip 2 expand in the radial direction, the sealing structure is tightly attached to the casing pipe, and the slip teeth 8 are anchored on the sleeve to achieve the sealing and supporting effects. The plugging ball 18 is thrown from the well mouth, under the combined action of gravity and liquid flow, the plugging ball 18 is seated at one end of the cone 1 far away from the slip 2, and the through hole 5 of the soluble bridge plug is plugged, so that the segmented purpose is achieved.

The present invention further provides an interlayer plugging system, please refer to fig. 3, which includes a soluble bridge plug, a setting tool, and a setting adapter, wherein the soluble bridge plug is the soluble bridge plug in the above embodiment. The setting rod 14 of the setting adapter extends into the through hole 5 of the soluble bridge plug and is connected with a setting tool, and the setting rod, the setting tool and the setting tool are matched to realize the setting of the soluble bridge plug. So set up, the guide shoe 3 of soluble bridge plug is equipped with fluting 7 and concave position 6, fluting 7, concave position 6 and through-hole 5 intercommunication, shutoff ball 18 takes a seat at concave position 6, restrict the position of shutoff ball 18 through concave position 6, simultaneously, flowback well fluid is by fluting 7, concave position 6 through flowing into through-hole 5, the blowback ball does not influence the blowout flowback of well fluid, the shutoff ball 18 of having solved among the prior art previous interval is big to the blowout flowback resistance, perhaps even with the problem of flowback passageway jam. The derivation of the beneficial effect is substantially similar to that of the above soluble bridge plug, and therefore, the description thereof is omitted.

In the preferred scheme of this embodiment, the setting adapter includes setting pole 14 and setting section of thick bamboo 15, and setting pole 14 wears to establish in the through-hole 5 of soluble bridging plug, and setting section of thick bamboo 15 is connected with the one end that the cone 1 keeps away from slips 2, and the one end that sets pole 14 keeps away from guide shoe 3 passes through setting section of thick bamboo 15 and is connected with the setting instrument, and the other end of setting pole 14 is connected with guide shoe 3.

The inner wall of the guide shoe 3 is provided with a convex ring 301 which is convex towards the central axis direction, the setting rod 14 penetrates through the guide shoe 3, the outer wall of the setting rod is provided with a step structure 141 which is matched with the convex ring 301, one side of the convex ring 301, which is far away from the slip 2, is also provided with a shearing ring 16, and the shearing ring 16 is in threaded connection with the setting rod 14. The shearing limiter 17 is connected with the inner part of one end of the setting cylinder 15 connected with the cone 1, and the shearing limiter 17 is connected with the setting rod 14. The inner surface of the cone 1 at the end near the guide shoe 3 is provided with an inclined guide surface for guiding the removal of the setting stem 14 of the setting adapter. The soluble bridge plug achieves a release when the setting force generated by the setting tool exceeds the thread shear force between the shear ring 16 and the setting stem 14. The releasing mode does not need to shear pins, and no shear pins remain at the bottom of the well after releasing; furthermore, the connection of the soluble bridge plug components directly or indirectly with the setting stem 14 of the setting adapter can avoid premature setting of the soluble bridge plug when it is run into the well.

After the tool string is lowered to the designed depth, the setting is started through cable ignition or hydraulic pressure, the setting tool generates thrust to push a setting barrel 15 of a setting adapter, so that the cone 1 is pushed to move towards the direction close to the guide shoe 3, the sealing mechanism 4 is expanded through the movement of the cone 1, the expansion ring 401 and the sealing ring 402 are opened, meanwhile, the slips 2 are opened, when the sealing mechanism 4 is completely attached to the inner wall of the casing and certain extrusion is carried out, and after the slips 2 are anchored to the inner wall of the casing, the soluble bridge plug setting is completed, at the moment, the cone 1 is firmly wedged together with the slips 2, and the downward movement cannot be continued.

After the soluble bridge plug is set, the pushing force generated by the setting tool is continuously increased, and when the pushing force is increased to the thread shearing force between the shearing ring 16 and the setting rod 14, the setting rod 14 and the shearing ring 16 are pulled out of the guide shoe 3, so that the setting adapter is separated from the soluble bridge plug.

And (3) putting the plugging ball 18 into the well-set soluble bridge plug in a free falling mode or pumping mode, wherein the plugging ball 18 seals the end of the cone 1, and the annular space between the cone 1 and the sleeve is sealed by a sealing ring, so that the upper fracturing layer section and the lower fracturing layer section are sealed.

After the fracturing operation is finished, blowout and flowback are carried out, the plugging ball 18 of the previous layer section is seated on the concave position 6, and flowback well fluid can enter the concave position 6 through the open slot 7 beside the flowback ball, then flow into the through hole 5 and flow towards the direction of a well head.

It is understood that the same or similar parts in the above embodiments may be mutually referred to, and the same or similar parts in other embodiments may be referred to for the content which is not described in detail in some embodiments. The multiple schemes provided by the invention comprise basic schemes, are independent from each other and are not restricted with each other, but can be combined with each other under the condition of no conflict, so that multiple effects are realized together.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.

Claims

1. The utility model provides a soluble bridge plug, its characterized in that, including cone (1), slips (2) and guide shoe (3) that connect gradually, the outer wall of cone (1) with the juncture of slips (2) is equipped with sealing mechanism (4), cone (1) slips (2) with the inside of guide shoe (3) all is equipped with along axial extension, and through-hole (5) that communicate each other, the guide shoe (3) is kept away from the one end of slips (2) is equipped with recess position (6) that supply to return row ball to take a seat and supply to return fluting (7) that row well liquid flows through, fluting (7) recess position (6) and through-hole (5) are linked together, it flows through in proper order to return row well liquid fluting (7) recess position (6) flow into in through-hole (5).

2. Soluble bridge plug according to claim 1, characterized in that the slots (7) are provided in at least two and are evenly distributed in the circumferential direction of the guide shoe (3), each slot (7) extending in the radial direction of the guide shoe (3).

3. The soluble bridge plug according to claim 1, characterized in that the end surface of the end of the shoe (3) remote from the slip (2) is connected with the peripheral side wall of the shoe (3) by a curved transition.

4. The soluble bridge plug according to claim 1, wherein the sealing mechanism (4) comprises an expansion ring (401) and a sealing ring (402) which are sleeved on the outer wall of the cone (1), the outer peripheral wall of the expansion ring (401) is provided with an annular groove, and the sealing ring (402) is arranged in the annular groove.

5. A soluble bridge plug according to claim 1, wherein a plurality of slip elements (8) are embedded in the slip (2), the angle between the axial direction of the slip elements (8) and the axial direction of the slip (2) being less than 90 °; the end part of the slip (2) is provided with a convex block (9) protruding along the axial direction, the end part of the guide shoe (3) is provided with a groove (10) recessed along the axial direction, and the convex block (9) extends into the groove (10).

6. Soluble bridge plug according to claim 1, characterized in that the outer surface of the cone (1) near the end of the guide shoe (3) is provided with external toothing (11) and the inner surface of the slip (2) is provided with internal toothing (12) which meshes with the external toothing (11).

7. Soluble bridge plug as claimed in claim 1, characterized in that the guide shoe (3) is embedded on its peripheral side wall with a plurality of wear-resistant particles (13).

8. An interbedded plugging system comprising a soluble bridge plug according to any one of claims 1 to 7, a setting tool, a setting adaptor.

9. The interlaminar plugging system of claim 8, wherein the setting adapter comprises a setting rod (14) arranged in the through hole (5) in a penetrating mode and a setting barrel (15) connected with one end, away from the slip (2), of the cone (1), one end of the setting rod (14) penetrates through the setting barrel (15) to be connected with the setting tool, and the other end of the setting rod is connected with the guide shoe (3).

10. The interlaminar plugging system according to claim 9, characterized in that the inner wall of the guide shoe (3) is provided with a convex ring (301) which protrudes towards the central axis direction, the outer wall of the setting rod (14) is provided with a step structure (141) which is matched with the convex ring (301), one side of the convex ring (301) far away from the slip (2) is further provided with a shearing ring (16), and the shearing ring (16) is in threaded connection with the setting rod (14).