Casing Patch

Abstract

Systems and methods for patching a casing are disclosed. A casing patch has two concentric cylinders and a setting ring having ratcheting teeth that prevent radial contraction and prevent radial expansion. A radially outwardly directed force sets the casing patch at a desired location which seals against the casing and can withstand pressures of up to 20,000 psi. A deployment tool comprising corresponding cones can impart a downward force into the radially outwardly directed force, and can release from the casing patch as desired.

Description

BACKGROUND

Perforating and fracturing operations involve the use of high pressure and explosive conditions which, in addition to the normally harsh environment in a well, can cause damage to a casing. Repairing damaged casing is in many instances not even attempted due to the high cost and low success rate of current repair operations, leaving many otherwise productive zones underutilized. There is a need in the art for a cost-effective casing repair solution.

SUMMARY

Embodiments of the present disclosure are directed to an apparatus including a first element having a generally cylindrical shape, an interior surface, and an exterior surface. The first element has a length sufficient to cover an interior surface of a desired region of a casing within a well. The apparatus also includes a second element having a generally cylindrical shape, an interior surface, and an exterior surface, the second element having a length substantially coextensive with the first element, the second element having a smaller radius than the first element such that the second element fits within the first element with the outer surface of the second element contacting the interior surface of the first element. The apparatus also includes a setting ring positioned between the first and second elements, the setting ring having a circumferential, ratcheted cut extending around the setting ring's circumference. The ratcheted cut permits circumferential expansion of the setting ring and prevents circumferential contraction of the setting ring. The first element, second element, and setting rings comprise a patch for the casing. The apparatus also includes a deployment tool configured to carry the patch to a desired location in the well and to exert a radially outward force on the patch sufficient to deform the patch onto the casing to seal the casing at the desired location.

Further embodiments of the present disclosure are directed to a method for sealing a portion of a casing in a well. The method includes positioning a patch in the well at a desired location, the patch comprising two concentric cylindrical elements and a setting ring, the setting ring comprising an outer ring and an inner ring. The outer ring and inner ring have corresponding ratchet teeth that permit radial expansion and prevent radial contraction. The method also includes exerting a setting force onto a deployment tool, wherein the deployment tool is configured to impart the setting force into a radially outward force sufficient to expand the setting ring and the patch in a radially outward direction to seal against the casing at the desired location. The method also includes collapsing the deployment tool such that the deployment tool releases from the patch, and pulling the deployment tool out of the well with the patch secured to the casing.

Other embodiments of the present disclosure are directed to a casing patch including a first cylinder having a first stiffness and an outer diameter, and a second cylinder having a second stiffness less than the first stiffness, the second cylinder surrounding the first cylinder and having an inner diameter substantially equal to the outer diameter of the first cylinder such that the first and second cylinders are friction fit together. The second cylinder has a recess on an interior surface. The casing patch also includes a setting ring positioned within the recess in the second cylinder, the setting ring having ratcheted teeth that permit radial expansion and prevent radial contraction. Applying a setting force causes the setting ring to permanently expand due to the ratcheted teeth and to seal onto a casing in a well. In further embodiments the casing patch also includes a deployment tool configured to impart a downward force into a radially outward force applied in 360 degrees around a circumference of the deployment tool to set the casing patch. The deployment tool is further configured to release the casing patch and be pulled out of the well.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a perspective view of a casing patch according to embodiments of the present disclosure.

FIG. 2 is a cross-sectional view of the casing patch according to embodiments of the present disclosure.

FIG. 3 is a side view of the setting rings according to embodiments of the present disclosure.

FIG. 4 is a close up view of a scarf cut according to embodiments of the present disclosure.

FIG. 5 is a cross-sectional view of a casing patch including a deployment tool according to embodiments of the present disclosure.

FIG. 6 is a cross-sectional view of the outer cone according to embodiments of the present disclosure.

FIG. 7 is a cross-sectional view of the outer cone and inner cone according to embodiments of the present disclosure.

DETAILED DESCRIPTION

Below is a detailed description according to various embodiments of the present disclosure. FIG. 1 is a perspective view of a casing patch 100 according to embodiments of the present disclosure. The casing patch 100 is a generally cylindrical structure that can be placed into position in a well to cover a damaged region of the casing and once situated and set, the casing patch 100 can cover a damaged area with sufficient strength to allow production to continue. The casing patch 100 can have an outer layer 102 and an inner layer 104 that is substantially coextensive with the outer layer 102. The casing patch 100 can include slips 106 on an outer surface 108 to permit the casing patch to grip the casing as is the customary use of slips. There can be any number and arrangement of slips. Other anchoring and fixation methods can also be used without departing from the scope of the present disclosure. The casing patch 100 can also include a setting ring 110 shown in phantom on the interior of the casing patch that will be described in greater detail and shown to greater advantage in FIG. 2. The setting ring 110 can be expanded to urge the casing patch outward to set the casing patch onto the damaged area of the casing.

FIG. 2 is a cross-sectional view of the casing patch 100 according to embodiments of the present disclosure. As described above, the casing patch includes an outer layer 102, an inner layer 104, setting rings 110, and slips 106. There can be any suitable number of setting rings. The casing patch 100 is shown inside of a casing 112 which has a damaged area 118. In some embodiments the casing patch 100 is sized to be larger than the damaged area 118 and can have setting rings 110 sufficient to seal around the damaged area. As shown here, there can be two rings one above and one below the damaged area 118. Other configurations are also possible. In some embodiments the casing patch 100 includes fold-back rings 120 and an elastomeric element (not shown) on an outer surface to help form a seal with the casing 112.

The outer and inner layers of the casing patch 100 can be interference-fitted together when assembled. The outer layer can have distinct material properties from the inner layer. In some embodiments the inner layer 104 can be made of corrosion resistant stiffer alloy (<160 ksi) with high elongation to failure (up to 25%). Such a material can be an IN 625 Plus alloy. The outer layer 102 can be made of corrosion resistant softer alloy (<80 ksi) with high elongation to failure (up to 50%).

In some embodiments the outer layer 102 can be manufactured with a recess on an interior surface that is configured to receive the setting rings 110 within the recess. The inner layer 104 can therefore be installed inside the outer layer 104 covering the setting rings 110. In some embodiments the inner layer 104 can be thinner and stiffer than the outer layer 102. In some embodiments the inner layer 104 can also include a recess configured to receive the setting rings 110. In yet other embodiments the setting rings 110 can be positioned in the inner layer 104 and not in the outer layer 102.

The casing patch 100 can be positioned in the well via a tool such as coil tubing or a specialized tool. Once in position, a force can be applied to the interior of the casing patch 100 sufficient to deform the setting rings 110 outwardly such that the setting rings 110 enlarge and lock into place. The casing patch 110 can therefore be flow formed onto the casing to seal and enable re-fracturing in the well.

FIG. 3 is a side view of the setting rings 110 according to embodiments of the present disclosure. The setting rings 110 can be formed as a cylindrical single piece of material which is subject to a process to make a scarf cut around the ring 110. The rings can be made out of a high-strength spring alloy. The scarf cut results in an inner portion 114 and an outer portion 116, with a ratcheted, jagged cut between them. When the ring is expanded, the ratchets prevent reversal of the expansion, thus locking the setting rings in an enlarged state to seal the casing patch in place.

FIG. 4 is a close up view of a scarf cut according to embodiments of the present disclosure. The setting ring 110 has an outer portion 116 and an inner portion 114, with a jagged, ratcheting cut 126 between them. In some embodiments a first end 130 of the inner portion 114 is urged away from a second end 132, causing a gap 128 to form between the first end 130 and the second end 132. The jagged profile of the cut prevents the ring from contracting once expanded. The force to expand the rings can be applied radially outwardly to the ring.

FIG. 5 is a cross-sectional view of a casing patch 100 including a deployment tool 140 according to embodiments of the present disclosure. The deployment tool 140 can be connected to the casing patch during run-in-hole where it is used to apply an outward force onto the casing patch 100 sufficient to set the patch in place. It is then released from the patch and retrieved. The deployment tool 140 can include an inner cone 144, an outer cone 142, an adapter 148, and a connector 146. The inner cone 144 can have a slight slope to an outward surface that matches a corresponding slight slope to an inner surface of the outer cone 142. These surfaces operate together such that a downward force applied to the inner cone 144 causes outward expansion of the outer cone 142. In some embodiments the deployment tool 140 is capable of providing up to 75,000 pounds of pressure downward. The outer cone 142 will deform outwardly imparting the desired radially outward force onto the casing patch 100 to set the setting rings 110 and set the patch. The deployment tool 140 also includes set screws 150 that connect the outer and inner cones together that are sheared to allow relative movement in an axial direction between outer and inner cones. The outer cone 142 includes a nose 148 configured to stop the deployment tool 140 in the desired position relative to the casing patch 100. In some embodiments the nose 148 is positioned adjacent to a setting ring 110 as shown here. In other embodiments the setting ring(s) can be at different locations.

FIG. 6 is a cross-sectional view of the outer cone 142 according to embodiments of the present disclosure. The outer cone 142 includes a nose 148 and a plurality of fingers 152 separated by relief cuts to permit outward expansion as the deployment tool is urged downward. The dimensions of the relief cuts can depend on the forces and geometry of other components in the system. The outer cone 142 can include hardened (ion nitride etc.) on an interior diameter to allow the cone 142 to smoothly actuate and expand the fingers 152. The fingers 152 can include a rounded feature as a line contact to reduce friction during deployment. The cone 142 can include stress-relieving holes at the end of the slots to prevent cracking. The cone 142 can collapse once it reaches a fully-deployed position at which point it will cease to impart the outward force on the cone, thus allowing the deployment tool to be pulled out of the hole.

FIG. 7 is a cross-sectional view of the outer cone 142 and inner cone 144 according to embodiments of the present disclosure. The inner cone 144 has an interior recess configured to receive the adapter (shown in FIG. 5). The inner cone can also have slots 160 that permit the cone to flex at a desired time to deploy the casing patch. The recess that holds the adapter can have notches 162 that hold the adapter in place in the inner cone with a friction-fit fixture.

The casing patch systems and methods of the present disclosure enable re-fracturing of existing zones previously not possible. The casing patch can withstand pressures exceeding 20,000 psi and temperatures of 450 degrees F. The deployment mechanism enables a force of up to 75,000 lbs to deploy the casing patch in a precise zone to remedy a damaged area or seal a perforation. In some embodiments the shear pins are configured to withstand slightly less than the rating of the deployment tool. For example, if the deployment tool is rated to set at 75,000 lbs, the shear pins can be rated for 70,000 such that the shear pins shear before reaching the final deployment load of the deployment tool.

The foregoing disclosure hereby enables a person of ordinary skill in the art to make and use the disclosed systems without undue experimentation. Certain examples are given to for purposes of explanation and are not given in a limiting manner.

Claims

1. An apparatus, comprising: a first element having a generally cylindrical shape, an interior surface, and an exterior surface, the first element having a length sufficient to cover an interior surface of a desired region of a casing within a well;a second element having a generally cylindrical shape, an interior surface, and an exterior surface, the second element having a length substantially coextensive with the first element, the second element having a smaller radius than the first element such that the second element fits within the first element with the outer surface of the second element contacting the interior surface of the first element;a setting ring positioned between the first and second elements, the setting ring having a circumferential, ratcheted cut extending around the setting ring's circumference, wherein the ratcheted cut permits circumferential expansion of the setting ring and prevents circumferential contraction of the setting ring;wherein the first element, second element, and setting rings comprise a patch for the casing;a deployment tool configured to carry the patch to a desired location in the well and to exert a radially outward force on the patch sufficient to deform the patch onto the casing to seal the casing at the desired location.

2. The apparatus of claim 1, further comprising slips on the exterior surface of the first element.

3. The apparatus of claim 1, further comprising an elastomeric sealing element on the exterior surface of the first element.

4. The apparatus of claim 1, further comprising fold-back shoes on the exterior surface of the first element.

5. The apparatus of claim 1 wherein the setting ring comprises a first setting ring, the apparatus further comprising a second setting substantially similar to the first setting ring.

6. The apparatus of claim 5 wherein the first and second setting rings are spaced apart sufficiently to surround a desired area of the casing.

7. The apparatus of claim 1 wherein the first element is made of a first material and the second element is made of second material, the second material being stiffer than the first material.

8. The apparatus of claim 7 wherein the first material has a stiffness of approximately 80 ksi and the second material has a stiffness of approximately 160 ksi.

9. The apparatus of claim 1 wherein the deployment tool comprises an inner cone and a corresponding outer cone having slopes configured to transmit a downward force into an outward radial force sufficient to set the setting ring.

10. The apparatus of claim 9 wherein at least one of the outer cone and inner cone has slots to permit flexure.

11. The apparatus of claim 9 wherein the deployment tool is configured to deliver approximately 75,000 lbs of force to set the setting rings.

12. The apparatus of claim 9 wherein the deployment tool is configured to release from the patch and to be pulled out of the well.

13. The apparatus of claim 1 wherein the setting ring is situated in a recess, wherein the recess is positioned in either the first element at the interior surface, the second element at the exterior surface, or partially in the first element at the interior surface and the second element at the exterior surface.

14. A method for sealing a portion of a casing in a well, the method comprising: positioning a patch in the well at a desired location, the patch comprising two concentric cylindrical elements and a setting ring, the setting ring comprising an outer ring and an inner ring, wherein the outer ring and inner ring have corresponding ratchet teeth that permit radial expansion and prevent radial contraction;exerting a setting force onto a deployment tool, wherein the deployment tool is configured to impart the setting force into a radially outward force sufficient to expand the setting ring and the patch in a radially outward direction to seal against the casing at the desired location;collapsing the deployment tool such that the deployment tool releases from the patch; andpulling the deployment tool out of the well with the patch secured to the casing.

15. The method of claim 14 wherein exerting the setting force comprises exerting 75,000 lbs of force in a downward direction.

16. The method of claim 14, wherein collapsing the deployment tool comprises shearing a shear pin.

17. The method of claim 14 wherein the two concentric cylindrical element comprise a first element having a first strength and a second element having a second strength greater than the first strength, and wherein the second element is smaller than the first element and positioned within the first element.

18. The method of claim 14, further comprising setting slips on an exterior surface of the patch.

19. A casing patch, comprising: a first cylinder having a first stiffness and an outer diameter;a second cylinder having a second stiffness less than the first stiffness, the second cylinder surrounding the first cylinder and having an inner diameter substantially equal to the outer diameter of the first cylinder such that the first and second cylinders are friction fit together, wherein the second cylinder has a recess on an interior surface; anda setting ring positioned within the recess in the second cylinder, the setting ring having ratcheted teeth that permit radial expansion and prevent radial contraction, wherein applying a setting force causes the setting ring to permanently expand due to the ratcheted teeth and to seal onto a casing in a well.

20. The casing patch of claim 19, further comprising a deployment tool configured to impart a downward force into a radially outward force applied in 360 degrees around a circumference of the deployment tool to set the casing patch, wherein the deployment tool is further configured to release the casing patch and be pulled out of the well.