Delayed fin deployment wiper plug

Abstract

A delayed fin deployment wiper plug has a tubular body, which has a closed top and a piston therein. The piston is supported at one or more locations inside the tubular body by one or more sets of shear pins or spring clips or some equivalent device. The piston is connected to or abutted to a sleeve that covers an upper portion of the tubular body, containing therein one or more sets of deployable fins that are not exposed for use unless the piston is activated and raises the sleeve.

Claims

1. A delayed fin deployment wiper plug, said wiper plug comprising; (a) a tubular body having an open base and a closed top; (b) said closed top having a hole therethrough; (c) said tubular body having a first set of a plurality of flexible fins circumnavigating a circumference of an exterior surface at a lower end of said tubular body; (d) a piston slidingly fitted through said hole, said piston comprising a piston rod and a piston base; (e) said piston base supported at a first location inside said tubular body by one or more reversible connectors; (f) said piston rod and piston base and closed top forming a compression chamber inside an upper portion of said tubular body; (g) a sleeve over said upper portion of said tubular body, said sleeve having an open base and a closed sleeve top; (h) said piston rod abutting or connected to said closed sleeve top; (i) a second set of a plurality of flexible fins circumnavigating a circumference of an exterior surface at said upper end of said tubular body and contained within said sleeve; and (j) said sleeve being of smaller diameter than a diameter of deployed fins.

2. The wiper plug of claim 1, wherein said fins are upwardly angled fins.

3. The wiper plug of claim 1, wherein said fins are upwardly angled fins comprising an elastomeric material.

4. The wiper plug of claim 1, wherein said fins are upwardly angled fins and said fins and said tubular body comprise an elastomeric material.

5. The wiper plug of claim 1, wherein said fins are upwardly angled fins and said fins comprise an elastomeric material and said tubular body comprise a metal interior surface.

6. The wiper plug of claim 1, wherein said sleeve and said piston comprise metal.

7. The wiper plug of claim 1, wherein said fins are upwardly angled fins and said fins comprise an elastomeric material and said tubular body comprised a metal interior surface and said sleeve and said piston comprise metal.

8. A method of cleaning a wellbore, comprising deploying the wiper plug of claim 1 in a wellbore at a first pressure to clean a first portion of wellbore, changing said pressure, and deploying said second set of a plurality of flexible fins to clean a second portion of said wellbore.

9. A delayed fin deployment wiper plug, said wiper plug having a tubular body having a closed top and a piston therein, the piston being connected to or abutting a sleeve that covers an upper portion of said tubular body and houses therein one or more sets of deployable fins that are not exposed for use until said piston is activated and raises said sleeve, wherein said piston is supported at one or more positions inside said tubular body by one or more sets of shearable connectors, and high pressure shears said shearable connectors and raises said sleeve.

10. The wiper plug of claim 9, wherein said wiper plug has two sets of shearable connectors, and an upper set of shearable connectors requires more force to shear than a lower set of shearable connectors.

11. The wiper plug of claim 10, wherein said shearable connector is a shear pin, shear screw, or a shear bolt.

12. A method of cleaning a well bore comprising: (a) pumping a fluid through a wellbore at a first pump rate; (b) deploying a delayed fin wiper plug into said wellbore, said delayed fin wiper plug comprising: i) a tubular body having an open base and a closed top; ii) said closed top having a hole therethrough; iii) said tubular body having a first set of a plurality of flexible fins circumnavigating a circumference of an exterior surface at a lower end of said tubular body, said first set of fins cleaning a first portion of said wellbore at said first pump rate; iv) a piston slidingly fitted through said hole, said piston comprising a piston rod and a piston base; v) said piston base supported at a first location inside said tubular body by one or more reversible connectors; vi) said piston rod and piston base and closed top forming a compression chamber inside an upper portion of said tubular body; vii) a sleeve over said upper portion of said tubular body, said sleeve having an open base and a closed sleeve top; viii) said piston rod abutting or connected to said closed sleeve top; ix) a second set of a plurality of flexible fins circumnavigating a circumference of an exterior surface at said upper end of said tubular body and contained within said sleeve; and x) said sleeve being of smaller diameter than a diameter of deployed fins; (c) pumping said fluid at a second lower rate thereby decreasing the pressure in the wellbore and thereby removing said one or more reversible connectors; and (d) expanding said compression chamber sliding said sleeve off of said second set of flexible fins, wherein said second set of fins cleans a second portion of said wellbore.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a prior art well architectural diagram showing decreasing diameter with depth and cemented intervals.

(2) FIG. 2 shows a variety of different prior art wiper plugs.

(3) FIG. 3 shows a prior art wiper plug used in single stage cementing operation.

(4) FIG. 4 is a cross-sectional view of a deployable fin wiper plug.

(5) FIG. 5 shows the wiper plug of FIG. 4 with a second set of fins deployed.

(6) FIG. 6 is a cross-sectional view of a wiper plug with second and third sets of fins that can be sequentially deployed at, for example, changing pressure.

(7) FIG. 7 is a cross-sectional view of the wiper plug of FIG. 6 shown with a second set of fins deployed, but with a third set of fins still housed inside the protective sleeve.

DETAILED DESCRIPTION

(8) The disclosure provides novel wiper plugs with a second (or more) set(s) of wiper fins that are deployable on command. Generally speaking, the wiper plug has a piston that can be activated to raise a sleeve, under which are housed one or more additional fin sets. When the piston is activated, it lifts, raising the sleeve and exposing the fins that were previously hidden inside the sleeve.

(9) The piston can be activated in any suitable manner, and one common means would be to allow changing pressure to raise the sleeve, e.g., by shearing shear pins, screws, bolts and the like, or by overcoming the holding pressure of a spring clip, or other equivalent device. Other activation methods include timer activated, airbag activated, dissolvable retainer, deterioration of a retaining ring, deterioration of retaining wiper fins, and the like.

(10) The invention includes any one or more of the following embodiment(s), in any combination(s) thereof:

(11) In at least one embodiment, a delayed fin deployment wiper plug includes a tubular body having an open base and a closed top, the closed top having a hole therethrough, and the tubular body having a first set of a plurality of flexible fins circumnavigating a circumference of an exterior surface at a lower end of the tubular body. The delayed fin deployment wiper plug further includes a piston slidingly fitted through the hole, the piston including a piston rod and a piston base, the piston base supported at a first location inside the tubular body by one or more reversible connectors, and the piston rod and piston base and closed top forming a compression chamber inside an upper portion of the tubular body. The delayed fin deployment wiper plug further includes a sleeve over the upper portion of the tubular body, the sleeve having an open base and a closed sleeve top, and the piston rod abutting or connected to the closed sleeve top. The delayed fin deployment wiper plug further includes a second set of a plurality of flexible fins circumnavigating a circumference of an exterior surface at the upper end of the tubular body and contained within the sleeve, the sleeve being of smaller diameter than a diameter of deployed fins.

(12) In at least one embodiment, a delayed fin deployment wiper plug includes a tubular body having an open base and a closed top, the closed top having a hole therethrough, and the tubular body having a first set of a plurality of flexible fins circumnavigating a circumference of an exterior surface at a lower end of the tubular body. The delayed fin deployment wiper plug further includes a piston slidingly fitted through the hole, the piston including a piston rod and a piston base, the piston base supported at a first location inside the tubular body by one or more reversible connectors, and the piston rod and piston base and closed top forming a compression chamber inside an upper portion of the tubular body. The delayed fin deployment wiper plug further includes a sleeve over the upper portion of the tubular body, the sleeve having an open base and a closed sleeve top, and the piston rod abutting or connected to the closed sleeve top. The delayed fin deployment wiper plug further includes a second set of a plurality of flexible fins circumnavigating a circumference of an exterior surface at the upper end of the tubular body and contained within the sleeve, the sleeve being of smaller diameter than a diameter of deployed fins.

(13) In at least one embodiment, a delayed fin deployment wiper plug includes a tubular body having a closed top having a hole therethrough, the tubular body having a first set of a plurality of flexible fins circumnavigating a circumference of an exterior surface at a lower portion of the tubular body. The delayed fin deployment wiper plug further includes a piston slidingly fitted through the hole, the piston including a piston rod and a piston base, and the piston base supported at a first location inside the tubular body by a first set of reversible connectors. The delayed fin deployment wiper plug further includes a second set of reversible connectors above the first set of reversible connectors, the second set of reversible connectors having a higher shear strength than the first set of reversible connectors, and the piston rod and piston base and closed top forming a compression chamber inside an upper portion of the tubular body. The delayed fin deployment wiper plug further includes a sleeve over the upper portion of the tubular body, the sleeve having an open base and a closed sleeve top, and the piston rod abutting or connected to the sleeve top. The delayed fin deployment wiper plug further includes a second set of a plurality of flexible fins circumnavigating a circumference of an exterior surface of the upper portion of the tubular body and contained within the sleeve, above the first set of reversible connectors. The delayed fin deployment wiper plug further includes a third set of a plurality of flexible fins circumnavigating a circumference of an exterior surface of the upper portion of the tubular body and contained within the sleeve, above the second set of reversible connectors.

(14) In any wiper plug herein, the reversible connectors may be selected from spring clips, shear pins, shear screws, shear bolts, or an equivalent.

(15) In any wiper plug herein, the fins may be upwardly angled fins.

(16) In any wiper plug herein, the fins may be upwardly angled fins comprising an elastomeric material.

(17) In any wiper plug herein, the fins may be upwardly angled fins, and the fins and the tubular body may comprise an elastomeric material.

(18) In any wiper plug herein, the fins may be upwardly angled fins and may comprise an elastomeric material, and the tubular body may comprise a metal interior surface.

(19) In any wiper plug herein, the sleeve and the piston may comprise metal.

(20) In any wiper plug herein, the fins may be upwardly angled fins and comprise an elastomeric material, the tubular body may comprise a metal interior surface, and the sleeve and piston may comprise metal.

(21) In at least one embodiment, a delayed fin deployment wiper plug includes a wiper plug having a tubular body having a closed top and a piston therein, the piston being connected to or abutting a sleeve that covers an upper portion of the tubular body and houses therein one or more sets of deployable fins that are not exposed for use until the piston is activated and raises the sleeve.

(22) In any wiper plug herein, the piston may be supported at one or more positions inside the tubular body by one or more sets of shearable connectors, and a change in pressure shears the shearable connectors and raises the sleeve.

(23) In any wiper plug herein, the wiper plug may have two sets of shearable connectors, and an upper set of shearable connectors requires more force to shear than a lower set of shearable connectors.

(24) In any wiper plug herein, the shearable connector may be a shear spin, a shear screw, or a shear bolt, or an equivalent.

(25) In at least one embodiment, wiper plugs include a tubular body having a plurality of upwardly angled fins circumnavigating an exterior surface of the tubular body, where the improvement in the wiper plugs includes a piston in an upper portion of the tubular body, the piston being connected to or abutting a sleeve that covers the upper portion of the tubular body and houses therein at least one second set of deployable fins that are not exposed for use until the piston is activated and raises the sleeve.

(26) In any wiper plug herein, the wiper plug may further include holding means for holding the piston at one or more locations along the tubular body and means for selectively removing or deactivating the holding means.

(27) In any wiper plug herein, the wiper plug includes first holding means and second holding means above the first holding means, and the first holding means is removed or deactivated when a pressure exceeds a first pressure threshold, and the second holding means is removed or deactivated when a pressure exceeds a second pressure threshold higher than the first pressure threshold.

(28) In at least one embodiment, a method of cleaning a wellbore includes deploying the wiper plug herein in a wellbore at a first pressure to clean a first portion of wellbore, changing the pressure, and deploying the second set of a plurality of flexible fins to clean a second portion of the wellbore. This can be repeated with a third set of fins cleaning a third portion of the wellbore. The method can be used in any of a variety of downhole procedures, such as cementing a casing, plug and abandonment, pigging, and the like.

(29) In at least one embodiment, a method of cleaning a wellbore includes pumping a fluid through a wellbore at a first pump rate and deploying a delayed fin wiper plug into the wellbore. The delayed fin wiper plug includes: a tubular body having an open base and a closed top, the closed top having a hole therethrough, the tubular body having a first set of a plurality of flexible fins circumnavigating a circumference of an exterior surface at a lower end of the tubular body, the first set of fins cleaning a first portion of the wellbore at a first pump rate; a piston slidingly fitted through the hole, the piston including a piston rod and a piston base, the piston base supported at a first location inside the tubular body by one or more reversible connectors, the piston rod and piston base and closed top forming a compression chamber inside an upper portion of the tubular body; a sleeve over the upper portion of the tubular body, the sleeve having an open base and a closed sleeve top, the piston rod abutting or connected to the closed sleeve top; a second set of a plurality of flexible fins circumnavigating a circumference of an exterior surface at the upper end of the tubular body and contained within the sleeve, the sleeve being of smaller diameter than a diameter of deployed fins. The method further includes pumping the fluid at a second lower rate thereby decreasing the pressure in the wellbore and thereby removing the one or more reversible connectors. The method further includes expanding the compression chamber sliding the sleeve off of the second set of flexible fins, wherein the second set of fins cleans a second portion of the wellbore.

(30) FIG. 4 shows a cross section of the deployable fin wiper plug. The tubular body 401 has an open base 401B and a closed top 401T, with a hole 402 therethrough.

(31) Hole 402 is sized to allow piston rod 415R to slidably fit therethrough. Piston base 415B and piston rod 415R together make up piston 415, and the chamber being formed by the piston base 415B, piston rod 415R and tubular body top 401T being an atmospheric or compressible chamber 407.

(32) A second set of fins 413 is found under sleeve 411, which also has an open base 411B and closed top 411T. The second set of fins is compressed or bent inside the sleeve 411, which is of smaller diameter that the first set of fins 403 in an open position. Of course, the sleeve 411 must also be of smaller diameter than the casing or tubing being wiped.

(33) Bearings 409 allow the piston to slide up and down, but other means, such as grease, could be used. Shear pins 405 are sheared under sufficient pressure, thus raising the sleeve 411 and allowing the second set of fins 413 to deploy. FIG. 5 shows the pins 405 sheared off, and the pressure thus raising the base of the piston 415B, and thereby raising sleeve 411 and exposing the fresh fins 413, which now no longer being constrained can straighten to meet the casing wall, thus providing the wiping action.

(34) Piston 415 and sleeve 411 can be a single integrated piece or can be two or more pieces operably coupled in a more or less permanent manner or can be reversibly coupled. They could also be two or more separate pieces.

(35) The outer body is dimensioned to accommodate a small range of casing inner diameters. In addition, we have shown the cross-sectional shapes of the tubing as cylindrical, but the inner surface could be any shape, such as a square, pentagon, hexagon. However, most if not all oil wells and casings are tubular.

(36) FIG. 6 shows a second embodiment with two sets of shear pins, allowing first and second delayed deployments of fins. The tubular body 601 has an open base 601B and a closed top 4601T, with a hole 602 therethrough.

(37) Hole 602 is sized to allow piston rod 615R to slidably fit therethrough. Piston base 615B and piston rod 615R together make up piston 615, and the chamber being formed by the piston base 615B, piston rod 615R and tubular body top 601T being an atmospheric or compressible chamber 607.

(38) A set of fins 613A is always deployed. A second set of fins 613B and a third set 613C are found under sleeve 611, which also has an open base 611B and closed top 611T, and the second and third sets of fins are compressed or bent inside the smaller diameter sleeve 611.

(39) Bearings 609 allow the piston to slide up and down, and here two sets of shear pins 605A and 605B are provided, the lower set 605A shearing under lower pressure than the upper set 605B. Thus, at a first pressure, the first set 605A shears and the sleeve 611 raises, exposing the second set of fins 613A to deploy, and the piston is stopped by the second set of shear pins 605B. See FIG. 7. At a second higher pressure, the pins 605B shear off, thus raising the base of the piston 615B, and thereby raising sleeve 611 the rest of the way to expose the third set of fins 613B. This action can be repeated a plurality of times.

(40) The shear pins are exemplary only and other removable connectors could be used instead, such as spring clips, shear screws, shear bolts, rivets, and the like.

(41) With regard to materials suitable for the invention, a number of different ones may serve. For the fins, a generally resilient material, such as many different types of elastomers, polyvinyls, and rubbers well known in the relevant art may be used. Other plastics known in the art may serve as well.

(42) The tubular body can be the same material or a metal or can have a metal interior surface. Indeed, many wiper plugs have an aluminum core, and hard rubber or other resin exterior. The sleeve and piston are typically made of metal, such as aluminum or steel.

(43) A very simple plug style has been provided herein, but the plug can have any of the further modifications known in the art, such as stiffening rods inside the fins, plug connectors, and the like.

(44) In use, the wiper plug is used in any downhole application, being deployed down hole to wipe clean an inner surface of well tubing and removing any removable connector or holding means when it is time to deploy a set of fresh fins. Where the holding means are pressure activated, a first set of fresh fins is deployed by at least temporarily providing a pressure high enough to raise the piston. Additional sets of fins can be deployed by at least temporarily providing a pressure high enough to again raise the piston, and typically, each subsequent deployment requires increased pressure.