Non-Metallic Expandable Tubular

In the usage life of a well, the casing that lines the well can develop a leak, whether from an undesirable perforation, damage to the casing, or some other cause. This leak in the casing can cause issues with contamination both into and out of the well, issues with maintaining proper pressure in the well, and a myriad of other issues which necessitate repairing or replacing the casing in some fashion.

A method of repairing a leak in a well casing is to insert a tubular into the well to patch over the leaking area of the casing. Common problems encountered when utilizing tubulars include limited usable size due to the weight of the tubular and leaks in the tubular itself from seams, connection points, along with other problems.

This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.

In one aspect, embodiments disclosed herein relate to a system for lining a casing in a well. The system includes a tubular disposed inside of the casing that includes an inner circumferential surface delineating a conduit, an external circumferential surface, a first end, and a second end located downhole from the first end in the well. The tubular is configured to expand from an initial outer diameter to a final outer diameter that is equal to an inner diameter of the casing. The system also includes a slip disposed circumferentially around the external circumferential surface of the tubular configured to grip an inner surface of the casing. The system also includes an expansion subassembly configured to expand radially when activated and expand an area of the tubular around the expansion subassembly from the initial outer diameter to a final outer diameter. The system also includes a string that extends from a surface location through the conduit of the tubular to the expansion subassembly and configured to pull the expansion subassembly up-hole.

In one aspect, embodiments disclosed herein relate to a method for lining a casing in a well. The method includes forming a casing lining system by disposing a slip circumferentially around an external circumferential surface of a tubular with a first and a second end. The method also includes running the casing lining system into an interior of the casing, activating the slip to fix the tubular to the inner surface of the casing, activating the expansion subassembly to expand the tubular, disconnecting the expansion subassembly from the inner circumferential surface of the tubular, and pulling the expansion subassembly up-hole through the tubular by the string.

Other aspects and advantages of the claimed subject matter will be apparent from the following description and the appended claims.

In the following detailed description of embodiments of the disclosure, numerous specific details are set forth in order to provide a more thorough understanding of the disclosure. However, it will be apparent to one of ordinary skill in the art that the disclosure may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the description.

Throughout the application, ordinal numbers (for example, first, second, third) may be used as an adjective for an element (that is, any noun in the application). The use of ordinal numbers is not to imply or create any particular ordering of the elements nor to limit any element to being only a single element unless expressly disclosed, such as using the terms “before”, “after”, “single”, and other such terminology. Rather, the use of ordinal numbers is to distinguish between the elements. By way of an example, a first element is distinct from a second element, and the first element may encompass more than one element and succeed (or precede) the second element in an ordering of elements.

In the following description of, any component described regarding a figure, in various embodiments disclosed herein, may be equivalent to one or more like-named components described with regard to any other figure. For brevity, descriptions of these components will not be repeated regarding each figure. Thus, each and every embodiment of the components of each figure is incorporated by reference and assumed to be optionally present within every other figure having one or more like-named components. Additionally, in accordance with various embodiments disclosed herein, any description of the components of a figure is to be interpreted as an optional embodiment which may be implemented in addition to, in conjunction with, or in place of the embodiments described with regard to a corresponding like-named component in any other figure.

It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “an operator” includes reference to one or more of such operators.

Terms such as “approximately,” “substantially,” etc., mean that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.

It is to be understood that one or more of the steps shown in the flowcharts may be omitted, repeated, and/or performed in a different order than the order shown. Accordingly, the scope disclosed herein should not be considered limited to the specific arrangement of steps shown in the flowcharts.

Regarding the figures described herein, when using the term “down” the direction is toward or at the bottom of a respective figure and “up” is toward or at the top of the respective figure. “Up” and “down” are oriented relative to a local vertical direction. However, in the oil and gas industry, one or more activities take place in a vertical, substantially vertical, deviated, substantially horizontal, or horizontal well. Therefore, one or more figures may represent an activity in deviated or horizontal wellbore configuration. “Uphole” may refer to objects, units, or processes that are positioned relatively closer to the surface entry in a wellbore than another. “Downhole” may refer to objects, units, or processes that are positioned relatively farther from the surface entry in a wellbore than another. True vertical depth is the vertical distance from a point in the well at a location of interest to a reference point on the surface.

The present disclosure outlines a solution to repairing casing leaks in a well using a casing lining system that is configured to dispose a tubular within a well bore and seal said tubular against the inner surface of the well bore. Methods presented herein solve deficiencies in conventional systems because the casing lining system is manufactured and deployed as a singular tubular. Thus, the tubular has few to no seams or connection points that could create potential leak points and can be easily disposed within a well casing to repair said well casing. Furthermore, the tubular is made with material that is easier to drill out, if needed.

shows a casing lining systemdeployed within a well casingof a wellin accordance with one or more embodiments. The wellshown inis used for example purposes only and a person skilled in the art will appreciate that the wellmay have any wellbore schematic, well trajectory, or well design known in the art. The wellincludes, at least, a wellboredrilled into a formationand a well casingdisposed within the wellbore.

Particularly, after the wellborehas been drilled, the wellboreis stabilized with the well casingto prevent hole collapse, which may cause issues with operations inside the well. Well casingsare also used to prevent fluid migration between multiple downhole formations and to control the flow of fluids from the formationinto the well. A well casingmay be made of any suitably strong and durable material known in the art, such as a metal alloy, but are often made as long connected segments of steel pipe. The well casingmay further be cemented into place with a layer of cement (not shown) pumped between the formationand the installed well casing. The well casingmay be made of multiple casing tubulars, for instance, threadedly connected together.

The well casinghas an inner diameter and may be intentionally perforated in the process of utilizing the well. After the well casinghas been installed, a leakmay occur in the well casing. The leakcould develop from many different sources, such as imperfect threads between well casing sections, milling through the shoe of the well casingafter a cementing job, creating an undesirable perforation in the well casing, manufacturing faults in the well casing, etc.

In one or more embodiments, the casing lining systemcomprises an expandable tubularhaving an inner circumferential surfacedelineating a conduit, an external circumferential surface, a first end, and a second end. The first endis located opposite the second endalong the tubular. The first endis located downhole from the second endwhen the tubularis disposed in the well casing.

A first slipis arranged on the external circumferential surfaceof the tubularat the first endof the tubular. A second slipis arranged on the external circumferential surfaceat the second endof the tubular. An expansion subassembly (shown inas element number) is removably connected to the inner circumferential surfaceof the tubularand is used to expand the tubular. A stringis connected to the expansion subassemblyand is used to deploy the casing lining systeminto the well casing. The casing lining systemmay also include, for example, a first sealand a second sealarranged on the external circumferential surfaceof the tubularand/or integrated into the first slipand second slip, according to goals and conditions. While the embodiments shown depict two seals arranged on the external circumferential surfaceof the tubular, there may alternately be any number of seals according to the particular goals and conditions involved.

The tubularis configured to expand from an initial outer diameter to a final outer diameter. When the first sealand the second sealare located directly on the tubular, the first sealand the second sealare also configured to expand from an initial outer diameter to a final outer diameter as or before the tubularexpands.

In embodiments where the first sealand the second sealare packers, the first sealand the second sealexpand from the initial outer diameter to the final outer diameter when the first sealand the second sealare activated.

The initial outer diameter is less than the inner diameter of the well casing. The final outer diameter is substantially equivalent to the inner diameter of the well casingsuch that the external circumferential surfaceof the tubulartouches the inner surfaceof the well casingand the first sealand the second sealcreate a seal against the inner surfaceof the well casing.

The casing lining systemis configured to be lowered into a well casingto the depth of a casing leakand deployed to expand against the inner surfaceof the well casingand thus repair the casing leakin a manner similar to a patch. The casing lining systemis configured to be lowered by means of the stringwhich attaches from a control system at the surface (not shown) to the expansion subassemblywhich is attached to the inner circumferential surfaceof the tubularitself. The stringmay be any deployment mechanism known in the art, such as coiled tubing, drill pipe, workover pipe, slickline, wireline, etc.

The casing lining systemexpands by means of the expansion subassemblyexpanding and forcing the tubularto have the final outer diameter substantially equal to the inner diameter of the well casing. When deployed within a well casing, the tubularmay not extend to the surface and instead be entirely within the well casing, or the tubularmay extend all the way to the surface, depending on goals and conditions involved. The surface may be any location on or above Earth's surface.

In one or more embodiments, the tubularmay be made of a nonmetallic material configured to plastically deform under tension and thus allow for an expansion subassemblyto mechanically expand the tubularin a radial fashion to fit snugly against the inner surfaceof the well casing. The tubular may specifically be made of a polymer such as Acrylonitrile Butadiene Styrene (ABS), Polyvinyl Chloride (PVC), or other such suitable material as known in the art. When a plastically deformable material, such as ABS or PVC, is put under a tensile load such as the circumferential tensile load induced by the radial expansion of the expansion subassembly, the polymer chains that comprise such a material are readily able to shift over each other to cause the bulk material to stretch and thus relieve the tension. Such materials, when plastically deformed in such a way, lack a sufficient internal restorative force to reverse the deformation, leaving the material in that deformed state. A corresponding compressive force such as from a well casingor formationis not sufficient to reverse the circumferential and radial expansion of a tubularowing to the nature of plastic deformation. Furthermore, this material is easier to mill out as compared to tubulars made of metal alloys.

In one or more embodiments, the tubularis manufactured as a single piece with no seams or connections. For example, the tubularmay be made by extruding a polymer through a die to produce a continuous tubularof a size according to the die and as long as is necessary in a similar manner to producing plastic pipe. The continuous, seamless nature of a single piece tubularprovides advantages by minimizing stress concentrations that may occur at a seam or joint, minimizing pre-existing leaks that may occur at a seam or joint, and simplifying the handling of the tubularby removing the need to join sections of tubulartogether.

In accordance with one or more embodiments, the first slipand the second slipare activated through electronic means (e.g., a signal sent along the stringto the first slipand/or the second slip). In other embodiments, the first slipand/or the second slipare activated through mechanical means (e.g., slack off weight applied through the stringor hydraulic pressure applied through the string).

When the first slipand the second slipactivate, they expand or jut out from the tubularto grip or bite into the inner surfaceof the well casing. The first slipand the second slipare able to grip or jut into the inner surfaceof the well casingusing a gripping element, not pictured, such as metal teeth or buttons. Once the first slipand/or the second slipare engaged with the inner surfaceof the well casing, the first slipand/or the second slipcan hold the tubularwithin the well casing, allowing the expansion subassemblyto detach from the tubularand expand the tubular.

In accordance with one or more embodiments, the first slipactivates prior to the expansion subassemblydetaching from the inner circumferential surfaceof the tubularsuch that the first slipholds the tubularwithin the well casing. In further embodiments, the second slipactivates by the same means and at the same time as the first slip. In other embodiments, the second slipactivates as the expansion subassemblypasses through the tubularproximate the installation location of the second slipon the tubular.

The first sealand the second sealprovide a fluid-tight seal between the tubularand the inner surfaceof the well casing. In one or more embodiments, the first sealand second sealmay be an elastomeric band arranged around an external circumferential surfaceof the tubular, to be expanded along with the tubularagainst the inner surfaceof the well casing.

The elastomeric nature of the band comprising the first sealor second sealmay provide improved sealing against rough or dirty surfaces, such as the inner surfaceof the well casing, by easily conforming to the surface. Alternatively, the first sealand second sealmay be integrated with the first slipand second slipas a combination of gripping elements and elastomeric elements.

In some embodiments, the first slipand second slipmay likewise be composed of a different material that is capable of being expanded and conforming to a surface such as a soft plastic or soft metal such as lead. In one or more alternate embodiments, the first sealand/or the second sealis configured as a metal to metal seal.

In one or more alternate embodiments, the first sealand the second sealmay be packers. The packers may be any type of packer known in the art, such as hydraulic or mechanical packers. As such, the first sealand the second sealmay be activated as a traditional packer would, before or after the tubularexpands, to inflate and seal against the inner surfaceof the well casing. The first sealand/or second sealmay optionally be arranged in grooves or depressions in the tubularto aid in precise positioning of the first sealand/or the second seal.

The relative positions of the first slip, second slip, first seal, and second sealshown inare merely in accordance with example embodiments, however, a person skilled in the art will appreciate that the first slip, second slip, first seal, and second sealmay be located at different locations along the tubularwithout departing from the scope of the disclosure herein. For example, the first sealand second sealmay be arranged in any combination of uphole, downhole, or integrated with the first slipand second slipdepending on goals and conditions.

and subsequent figures are not necessarily shown to scale. The length of the proposed casing lining systemcould be as short as the slips, seals, and expansion subassemblywould allow, or as long as hundreds or thousands of feet and similarly could be a wide range of diameters.

In accordance with one or more embodiments, the stringmay be coiled tubing that is part of a coiled tubing system (not shown). Coiled tubing is a metallic tubular that has been machined as a continuous string deformed to coil around a spool. The coiled tubing is uncoiled from the spool to deploy downhole tools into the well. In accordance with one or more embodiments, the coiled tubing is attached to the expansion subassemblyand the expansion subassemblyis attached to the inner circumferential surfaceof the tubular. Alternately, any suitable tubularinstallation system known in the art such as a drilling rig, a workover rig, a slickline unit, or a wireline unit may be used for disposing this casing lining systeminto a well casing.

shows a cross section of a casing lining systemdisposed within the well casing in accordance with one or more embodiments. The casing lining systemmay include an expansion subassemblyin accordance with one or more embodiments. The expansion subassemblyis arranged on the downhole end of a stringand may be removably connected to the inner circumferential surfaceof a tubularby such means as shear pins or a friction connection.

By being connected to the tubular, the expansion subassemblyis able to support the weight of the tubularas the casing lining systemis being deployed into the well casing. The expansion subassemblyis in turn supported by the stringwhich extends from the expansion subassemblyto the surface.

The expansion subassemblyis configured to be selectively expanded with sufficient force to expand the tubular. In one or more embodiments, the stringis fluidly connected to a hydraulic mechanism in the expansion subassemblysuch that fluid pumped downhole through the stringis directed to the expansion subassembly. Thus, when the casing lining systemis at the appropriate depth, hydraulic fluid can be pumped under pressure from the surface, down the stringto the expansion subassemblyto expand the expansion subassemblywith sufficient force to expand the tubular. The expansion subassemblymay alternately be expanded by electronic means such as an electric motor comprised in the expansion subassemblyand configured to expand the expansion subassemblyunder sufficient force. The stringmay then include an electrical connection from the motor of the expansion subassemblyto a control system at the surface.

The expansion of the expansion subassemblyserves to circumferentially stretch and radially expand the tubularto conform to the inner surfaceof the well casing. When the tubularconforms to the inner surfaceof the casing, a seal is correspondingly formed by the first sealand second sealor simply from the tubularitself sealing against the inner surfaceof the casing which may occur even if the first sealand second sealare not used as part of the tubular. Similarly, the conformity of the tubularto the inner surfaceof the well casingmay provide for suspending the tubularin the wellby the action of the first slipand second slipor by the friction between the tubularand the inner surfaceof the casing itself if the first slipand second slipare not used as part of the tubular.

shows a cross section of the casing lining systembeing expanded in accordance with one or more embodiments. In one or more embodiments, after the initial expansion of the expansion subassemblyand at least the first sliphas engaged with the inner surfaceof the casing, the expansion subassemblyis forcefully drawn upwards through the tubularby means of tension applied to the stringfrom the surface to expand the tubularto the final outer diameter. The expansion subassemblymay be configured to reduce the friction between the expansion subassemblyand the tubularwith lubrication, low friction surfaces, rollers, or other such means to reduce the force necessary to draw the expansion subassemblythrough the tubular.

shows a cross section of the casing lining systemfully expanded in accordance with one or more embodiments. Once the tubularis completely expanded by the expansion subassembly, the first slip, second slip, first seal, and second sealare engaged, thus, the tubularis self-supporting in the welland seals the area of the casingcovered by the tubular, thus, repairing any casing leakor undesirable perforation. With the tubularthen installed, the expansion subassemblyis free to be drawn out of wellby the string, leaving the tubularbehind in the well.

shows a cross section of the casing lining systemas installed in accordance with one or more embodiments. With the tubularfully installed in the welland the expansion subassemblyand stringwithdrawn from the well, the casing leakis repaired, and fluid flow can proceed through the casing for further drilling, production, or other well life stage.

is a flowchart in accordance with one or more embodiments. In accordance with one or more embodiments, the method for utilizing the casing lining systemto repair a casing leakor undesirable perforation in a well casing is as follows. Stepis to form a casing lining systemby disposing a slip,circumferentially around an external circumferential surfaceof a tubularthat has a first endand a second end, connecting an expansion subassemblyto an inner circumferential surfaceof the tubularproximate the second endof the tubular, and connecting the expansion subassemblyto an downhole end of a string.

Stepis to run the casing lining systeminto an interior of the casingby lowering the stringinto the casing. When inserting the casing lining system, the first endof the tubularenters the casing prior to the second endof the tubular.

Stepis to activate the slip,included in the casing lining systemto grip into an inner surfaceof the casingto fix the tubularto the inner surfaceof the casing. In one or more embodiments, the slip,is activated independently of the expansion subassemblyby any means known in the art such as hydraulic or electrical power sent via the stringand expansion subassemblyto the slip,or any other means known in the art.

Stepis to activate the expansion subassemblyto cause the expansion subassemblyto expand and thereby correspondingly expand an area of the tubulararound the expansion subassemblyfrom an initial outer diameter to a final outer diameter. Depending on the configuration of expansion subassemblyused, activation may be accomplished with hydraulic or electrical power directed through the stringto the expansion subassemblyor any other means known in the art.

Stepis to disconnect the expansion subassemblyfrom the inner circumferential surface of the tubular. Disconnecting the expansion subassemblycan be accomplished by pulling, using the string, the expansion subassemblyin an up-hole direction once the slip,is engaged with the casing, to cause the expansion subassemblyto slide against the inner circumferential surface of the tubular and shear any shear pins and/or overcome any friction attachment holding the expansion subassemblyto the tubular.

Stepis to pull the expansion subassemblyup-hole using the stringso that the expansion subassemblypasses through the full length of the tubularto expand said tubularfrom an initial outer diameter to a final outer diameter that is equal to the inner diameter of the casing. With the tubularexpanded, any seals,on the tubularand/or integrated into the slips,are activated and seal against the inner surfaceof the casing. With the tubularfully expanded and installed, the expansion subassemblyand stringmay be pulled out of the casingso that he wellmay be put into use. Sometime after the tubularis installed in the casing, the tubularmay be milled out if, for example, the undesirable perforations repaired by the tubularbecome desirable once again.

Embodiments of the present disclosure may provide at least one of the following advantages. The tubularbeing nonmetallic reduces the risk of corrosion, allows for easy milling once installed, allows the tubularto be easily handled and deployed from a coil tubing unit, and allows the tubularto be one unjointed piece. The tubularmay be constructed of a lightweight nonmetallic material which would allow for a much larger tubularas opposed to a heavier metallic construction. The tubularbeing one piece minimizes possibility of leaks through seams or joints. The overall arrangement of tubularand expansion subassemblyallows the casing lining systemto be quickly and efficiently deployed to repair a well casing.