Patent ID: 12247465

DETAILED DESCRIPTION

Embodiments of the present disclosure are described below in detail with reference to the accompanying figures. In the following detailed description, numerous specific details are set forth in order to provide a more thorough understanding of the claimed subject matter. However, it will be apparent to one having ordinary skill in the art that the embodiments described 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. As used herein, the term “connected” or “connected to” may indicate establishing either a direct or indirect connection, and is not limited to either unless expressly referenced as such.

In one aspect, embodiments disclosed herein relate to apparatuses and methods for placing and setting a patch made with a eutectic alloy to seal a section of a well. The eutectic alloy patch may be set using a eutectic expandable liner, which may generally include a layer of eutectic alloy around an expandable liner, and a heating expansion assembly, which may generally include an expansion cone with a heater incorporated therein and a driver. The heating expansion assembly may be assembled to the eutectic expandable liner such that a heated expansion cone may be driven axially through the eutectic expandable liner to simultaneously heat and expand the eutectic expandable liner. Eutectic expandable liners according to embodiments of the present disclosure may be useful, for example, in sealing a section of a well having a loss zone (also sometimes referred to as a lost circulation zone), where fluid may be partially or totally lost in the hole (often referred to as lost circulation of loss-of-circulation).

Eutectic expandable liners, heating expansion assemblies, systems, and methods according to embodiments of the present disclosure are discussed in more detail below. In the below discussion, relative terms such as “lower,” “upper,” “bottom,” and “top” may refer to the direction relative to the surface of the well when the assembly is positioned downhole.

According to embodiments of the present disclosure, a eutectic expandable liner may include an expandable liner having a generally tubular body, such as a casing pipe, made of steel, aluminum, or other ductile metal, and an outer layer made of a eutectic alloy. A eutectic alloy is a mixture of two or more components (most commonly alloys) in a ratio at which the mixture melts at a lower temperature than the melting point of any one of the individual components. Eutectic alloys will melt and solidify at the same, single temperature (rather than over a temperature range), which is sometimes referred to as the eutectic point. Examples of eutectic alloys include bismuth-based alloys, such as alloys of bismuth and tin, or alloys of bismuth and germanium and/or copper.

Eutectic expandable liners are designed to be radially expanded from having an initial minimum inner diameter to having an expanded inner diameter greater than the initial minimum inner diameter. The dimensions of the eutectic expandable liner (including its initial minimum inner diameter and wall thickness) may be chosen such that the inner diameter can be strained outwards to an expanded inner diameter where the liner can contact the well without inducing failure in the liner.

FIG.1shows an example of a eutectic expandable liner100according to embodiments of the present disclosure. The eutectic expandable liner100includes an upper tubular body110and a lower cone housing120having an outer diameter greater than the outer diameter of the upper tubular body. The eutectic expandable liner100further includes a base122, where a circulation port124is formed through a central portion of the base122. As discussed in more detail below, the circulation port124may be sized and shaped to receive an activation plug, which may be sent downhole to plug the circulation port124during operation of the eutectic expandable liner100.

The eutectic expandable liner100may be made of multiple joints that are threaded together around a heating expansion assembly (e.g., an expansion cone132and/or expansion cone driver136, discussed more below). For example, in one or more embodiments, the base122may be a separate piece from the lower cone housing120. To assemble the system, at least a portion of a heating expansion assembly may be placed inside the lower cone housing120, and the base122is then threaded to the lower cone housing120to enclose the bottom of the lower cone housing122. The end of the lower cone housing120opposite the base122may then be threaded to an end of the upper tubular body110, such that the heating expansion assembly is held inside the assembled eutectic expandable liner100.

The upper tubular body110and lower cone housing120may be made of a ductile metal, such as steel or an aluminum alloy. In one or more embodiments, the outer diameter of the lower cone housing120may be selected to have a minimum clearance between the smallest restriction in the well that the eutectic expandable liner100is expected to travel through.

A eutectic alloy layer112is provided around the upper tubular body110. In some embodiments, a eutectic alloy layer112may entirely surround the circumference of the upper tubular body110. By surrounding the upper tubular body with the eutectic alloy layer, the eutectic alloy layer may be able to contact and seal a discrete circumferential section of a well without needing to rotationally align the liner with the section of the well.

The thickness of the eutectic alloy layer112may be designed to maintain the needed volume for sealing a section of a well, to account for expansion of the upper tubular body110, and/or to maintain a clearance between the eutectic alloy and the well wall while the assembly is run in hole (prior to expansion). For example, a clearance between the eutectic alloy and the well wall may be in the range of greater than 0 to about 0.5 inch (e.g., between 0.2 and 0.5 inches). If the clearance is too large, too much expansion is needed beyond the capacity of the materials used. If the clearance is too small, there is risk that the assembly may get stuck while running in hole. Additionally, in one or more embodiments, the eutectic alloy layer112may have a thickness ranging from about 0.25 inches to several inches thick, e.g., 2 inches, 3 inches, 4 inches, or more.

The eutectic alloy layer112may be applied around the outer surface of the upper tubular body110, for example, by sputtering, electroplating, or other deposition process. In some embodiments, a tubular pipe formed of eutectic alloy may be fitted concentrically around a tubular body base of an expandable alloy, where the outer eutectic tubular pipe forms the eutectic alloy layer112. In such embodiments, the outer eutectic tubular pipe may be anchored to the tubular body base, for example, using packers or stop collars.

In the embodiment shown inFIG.1, a bottom packer114extends entirely around the upper tubular body110, positioned between a bottom end of the eutectic alloy layer112and the lower cone housing120. In some embodiments, such as shown inFIG.1, a top packer116is also provided around the upper tubular body110and is positioned at an opposite axial end of the eutectic alloy layer112from the bottom packer114. In such manner, the bottom and top packers114,116border the eutectic alloy layer112. The bottom and top packers114,116may be conventional rubber packers known in the art. Additionally, the bottom and top packers114,116may be designed to have a thickness (as measured extending radially outward from the tubular body) capable of contacting and sealing around the well wall when the tubular body is expanded, which may thereby contain the eutectic alloy layer112when the eutectic alloy is heated and melted.

According to embodiments of the present disclosure, a heating expansion assembly may be assembled in a eutectic expandable liner before the assembly is run into a well. The heating expansion assembly may include an expansion cone with a heater incorporated therein and a driver for driving the expansion cone through the eutectic expandable liner. The heating expansion assembly may be assembled and positioned in the eutectic expandable liner such that the expansion cone is held at the bottom end of the liner.

For example, as shown inFIG.1, heating expansion assembly130according to embodiments of the present disclosure may be assembled in the eutectic expandable liner100. The heating expansion assembly130includes an expansion cone132having one or more heaters134incorporated into the expansion cone132.

In the embodiment shown, the expansion cone132has an annularly shaped body with a generally conical shaped upper axial end and a heater134provided around an outer surface of the expansion cone body. Specifically, the heater134is provided on a sloped surface131at the upper conical end of the expansion cone132. In some embodiments, one or more heaters may extend around an outer side surface of the expansion cone. For example, in some embodiments, heating wires may be positioned in small grooves formed around an outer sloped and/or side surface of the expansion cone. By integrating a heater at an upper conical end and/or around the outer side surface of the expansion cone, the heater may be positioned as close to the eutectic alloy layer of the liner as possible while the expansion cone is pulled through the liner, thereby allowing for more effective heating of the eutectic alloy layer.

Additionally, a central passage133extends axially through the expansion cone body. The central passage may provide fluid access through the expansion cone (e.g., well fluid as the assembly is sent downhole or hydraulic fluid for hydraulically activating the expansion cone) and/or electrical access to heaters incorporated in the expansion cone.

In an initial configuration, before the eutectic expandable liner100is expanded, the expansion cone132is provided in the lower cone housing120of the eutectic expandable liner100. The change in diameter from the lower cone housing120to the upper tubular body110may act as a stopper to prevent the expansion cone132from moving through the liner when the assembly is sent downhole to a target location and before activation of the expansion cone132. Further, in the embodiment shown, the upper sloped surface131at the conical end of the expansion cone may be oriented to push against a corresponding sloped surface along the change in diameter between the lower cone housing and the upper tubular body when the expansion cone132is activated to move through the upper tubular body.

The heating expansion assembly130further includes an expansion cone driver136connected to the expansion cone132. When the assembly is sent downhole, the expansion cone driver136is connected between the expansion cone132and a pipe string140extending through the well to the surface of the well.

Expansion cone drivers may be hydraulically powered to hydraulically drive the expansion cone. For example, in some embodiments, the expansion cone driver may use hydraulic power to pressurize the area under the expansion cone, which applies a force to drive the expansion cone upward, in a direction toward the connected pipe string. In some embodiments, the expansion cone driver may be hydraulically powered by converting downhole hydraulic power into mechanical energy using a hydraulic powered motor, such as a progressive cavity positive displacement pump (sometimes referred to as a mud motor in the drilling industry). In such embodiments, a hydraulic powered motor may be connected to the expansion cone driver, between the expansion cone driver and the pipe string.

For example,FIG.6shows an example of a heating expansion assembly600according to embodiments of the present disclosure where a progressive cavity positive displacement pump is used as the expansion cone driver602. However, other types of downhole driving equipment (e.g., hydraulically or electrically powered motors) may be used to move an expansion cone through the liner. In the embodiment shown, the expansion cone driver602has a helically shaped rotor604that rotates within a stator606as fluid flows through the volume between the rotor604and stator606, converting hydraulic power to mechanical rotation. The rotor604is connected to a threaded shaft605that is threaded to the central passage607of the expansion cone608. When fluid is flowed through the expansion cone driver602to rotate the rotor604, the connected threaded shaft605also rotates through the expansion cone608. The expansion cone608may have passages609formed axially therethrough to allow for fluid flow from operating the expansion cone driver602to pass through the expansion cone608. During operation of the expansion cone driver602, contact between the sloped surface of the expansion cone608and an inner surface of an expandable liner may prevent the expansion cone132from rotating with the threaded shaft605, and instead cause the expansion cone608to be threaded up the threaded shaft605. Alternatively, grooves may be provided in the outer surface of the expansion cone608or in an inner surface of an expandable liner, and corresponding, interlocking bridges may be provided on the other of the expansion cone outer surface or liner inner surface. The interlocking grooves/bridges may be formed linearly along the interfacing surfaces of the expansion cone and expandable liner to prevent the rotation of the expansion cone608with the respect to the expandable liner. In such manner, the expansion cone driver602may drive the expansion cone608upward through an expandable liner.

In one or more embodiments, electrical connectivity from the surface to a heater in the expansion cone may be provided through the expandable liner. For example, in embodiments such as shown inFIG.6, where an expansion cone608is driven through an expandable liner using a progressive cavity positive displacement pump as the expansion cone driver602, an electrical connection (e.g., including one or more wires) may be provided along the expandable liner in a configuration to electrically communicate with a heater in the expansion cone608.

According to embodiments of the present disclosure, a eutectic expandable liner and heating expansion assembly may be sent downhole to seal a section of a well by activating the heating expansion assembly to heat and expand the eutectic expandable liner in a single run. Examples of methods and systems for sealing a section of a well using a eutectic expandable liner and heating expansion assembly according to embodiments of the present disclosure are shown and discussed with respect toFIGS.2-5below.

Referring first toFIG.2, a eutectic expandable liner and heating expansion assembly200may be sent through a well202to a downhole location203on a pipe string204(e.g., a string of drill pipe or coiled tubing). During run-in, the pipe string204extends through the well202from wellhead equipment206located at an opening to the well. Other known supporting equipment (not shown) may be located at the surface of the well to run-in the pipe string and connected well equipment and to operate the scaling operation.

The eutectic expandable liner and heating expansion assembly200is positioned at the end of the pipe string204and includes a eutectic expandable liner210assembled with a heating expansion assembly. The eutectic expandable liner210includes a eutectic alloy layer212layered around the outer circumference of a tubular body of the liner, such that the eutectic alloy forms the liner's outer surface along an axial length of the liner, and packers fitted around the liner at the opposite axial ends of the eutectic alloy layer212. The axial length of the eutectic alloy layer212(and length of the liner) may be selected, for example, depending on the size of the well and the length of the well needing to be sealed. At the downhole location203, the assembly200may be positioned such that the eutectic alloy layer212extends across the length of the well needing to be sealed.

The heating expansion assembly includes an expansion cone220having at least one heater221provided around an outer surface of the cone body and an expansion cone driver222connected to the expansion cone220. In the embodiment shown, the expansion cone220is connected at an axial end of the expansion cone driver222, and an opposite axial end of the expansion cone driver222is connected to the end of the pipe string204, e.g., via a threaded connection. The eutectic expandable liner210may hang on the expansion cone220as the assembly is sent downhole.

The eutectic alloy layer212portion of the eutectic expandable liner210may be positioned axially above the expansion cone220as the assembly is sent downhole. For example, the expansion cone220may be provided in a lower cone housing portion of the eutectic expandable liner, where the expansion cone and the lower cone housing portion have outer diameters greater than the eutectic alloy layer212portion of the eutectic expandable liner210, which may prevent the expansion cone from moving through eutectic alloy layer212portion of the eutectic expandable liner210as the assembly is sent downhole.

To allow the assembly to be sent downhole without getting stuck, a maximum outer diameter of the assembly200prior to expansion (e.g., measured at the outer diameter of the lower cone housing portion of the liner) may range, for example, between ⅛ and ¼ inches under-gauge (smaller in diameter) than a wellbore inner diameter at the downhole location203. In some embodiments, an under-reaming operation may be performed prior to sending the eutectic expandable liner and heating expansion assembly downhole in order to enlarge the hole diameter so that prior to expansion the assembly fits in the open hole, and when the liner is expanded, the liner has an inner diameter equal to or smaller than the open hole inner diameter. In such embodiments, the bottom hole assembly (e.g., including a drill bit and/or reamers) is pulled out of the well prior to sending the eutectic expandable liner and heating expansion assembly into the well.

When the eutectic expandable liner and heating expansion assembly200is positioned at the downhole location203, such that the eutectic alloy layer112extends across the section of the well needing to be sealed, the pipe string204is set at the surface of the well using surface equipment, such as slips on a rotary table (not shown). As shown inFIG.2, a side-entry sub207is then connected to an upper end of the pipe string204. The side-entry sub may provide downhole access to the heating expansion assembly, as described more below.

After a eutectic expandable liner and heating expansion assembly is sent to a selected downhole location, the heater(s) on the expansion cone may be electrically activated and the expansion cone may be hydraulically activated to move axially through the eutectic expandable liner. The order in which an electrical connection is provided to the heater(s) and hydraulic power is provided may depend on the type of expansion cone driver used in the eutectic expandable liner and heating expansion assembly.

For example, in embodiments using a hydraulic motor as the expansion cone driver, a wireline may be run through the pipe string (e.g., via a side-entry sub) to provide an electrical connection to the assembly and then the hydraulic motor may be activated to drive the expansion cone while the heaters on the expansion cone are electrically powered.

In some embodiments, a turbine provided downhole in the pipe string may be used to convert hydraulic power (from fluid flowing through the pipe string, e.g., drilling fluid) into electricity, which may be used to provide electricity to the heater(s) of the expansion cone. The turbine may be provided as part of a downhole electric power generator. For example, a downhole electric power generator may include a fluid inlet (e.g., in fluid communication with the flow path through the pipe string to receive fluid being pumped therethrough or in fluid communication with the well annulus to receive fluid flowing through the well), a turbine in fluid communication with the fluid inlet, an electrical generator, and one or more optional transmission components between the turbine and electrical generator. Fluid flowing through the inlet to the turbine may rotate the turbine, where the electrical generator may convert the rotational energy generated from the turbine to electrical energy. The generated electrical energy may be transmitted to heater(s) of an expansion cone via one or more electrical cables and connections. In embodiments using a downhole electric power generator to electrically power heater(s) on an expansion cone, a wireline may not need to be run through the well (and thus a side-entry sub may not need to be connected to the pipe string).

In some embodiments, such as shown inFIGS.2-5, an expansion cone driver222is a fluid conduit that provides fluid from above the eutectic expandable liner210(e.g., from the surface of the well) to an enclosed volume below the expansion cone220to increase pressure below the expansion cone220. In such embodiments, the increased pressure below the expansion cone220is used to drive the expansion cone upwardly through the eutectic alloy layer212portion of the liner. As shown, the expansion cone driver222extends an axial length greater than the eutectic alloy layer212portion of the liner and has an outer diameter that fits through a central passage extending axially through the expansion cone220. In some embodiments, the expansion cone driver222may include a stopper that prevents the expansion cone220from sliding off the conduit.

While the expansion cone220shown inFIGS.2-5has a generally toroidal shape to allow fluid flow through its central passage, in other embodiments, an expansion cone may have a different shape, depending in part on the type of driving mechanism used to move the expansion cone axially upward through the eutectic expandable liner.

In the embodiment shown inFIGS.2-5, an enclosed volume223below the expansion cone220is formed, in part, by the lower cone housing portion of the liner assembly when the expansion cone220is held in an initial configuration prior to activation. For example,FIG.2shows the eutectic expandable liner and heating expansion assembly200in an initial configuration, where the expansion cone220is held in a lower cone housing portion of the eutectic expandable liner210. A circulation port224is formed through a base of the lower cone housing, where the circulation port224may allow circulation of fluid through the pipe string and well as the assembly is being sent downhole to a downhole location203. As shown inFIG.3, when the assembly is positioned at the selected downhole location203, an activation plug225is dropped to land on and seal the circulation port224. In one or more embodiments, the activation plug225may be sized to fit through a hole formed through a wireline connection seat226provided in the eutectic expandable liner and heating expansion assembly200(described more below). In such embodiments, the activation plug225may be dropped from the surface through the pipe string204used to deliver the assembly200downhole and through the connection seat226provided in the assembly200to land on and seal the circulation port224. With the activation plug225in sealing engagement with the circulation port224, a fully enclosed volume223(with a single fluid access via the expansion cone driver222) is formed below the expansion cone220, between the lower cone housing and a bottom surface of the expansion cone.

After the activation plug225is in place, a wireline208is run from the surface, through the side-entry sub207, to the eutectic expandable liner and heating expansion assembly200to provide power to the assembly.FIGS.3and4show an example of an electrical connection that may be formed using a wireline to provide power to the eutectic expandable liner and heating expansion assembly200, whereFIG.3shows a cross-sectional side view of the connection andFIG.4shows a traverse cross-sectional view of the connection. As shown, the wireline208includes a wireline plug209provided at its end. The wireline plug209may have a size and shape that corresponds with a connection seat226provided in the eutectic expandable liner and heating expansion assembly200. For example, as described above, the connection seat226may have a hole formed therethrough that allows passage of the activation plug225through the connection seat226, where an upper end of the hole is sized and shaped to receive and hold the wireline plug209. In one or more embodiments, the wireline plug209and upper end of the connection seat hole may have corresponding and mating tapered surfaces, where the wireline plug209fits into the upper end of the connection seat hole but is sized to where the wireline plug209does not pass through the connection seat hole.

According to embodiments of the present disclosure, a connection seat may be positioned centrally in the expansion cone and electrically connected to the expansion cone heater. In the embodiment shown, the connection seat226is provided inside the expansion cone driver222at an axially shared position with the expansion cone220. Electrical lines227run through the connection seat226to the expansion cone220to power the heater221on the expansion cone. Additionally, the wireline plug209may include electrically conducting outer surfaces, which may act as electrical connection points when contacted to corresponding electrical connection points in the connection seat226.

According to embodiments of the present disclosure, the wireline plug209may be sent downhole via wireline208until the wireline plug209lands on the connection seat226. Various types of guides (e.g., passages, sensors, magnets, or others) may be used to guide the wireline plug209to connect to the connection seat226. Once the wireline208is electrically connected to the expansion cone heater221via the wireline plug209and connection seat226, an operator may turn on and off the heater221according to a heating schedule for the sealing operation.

Referring now toFIG.5, with the circulation port224closed and the expansion cone heater221electrically connected to a power source (via the wireline), the expansion cone driver is activated to move the expansion cone in a direction from the lower cone housing toward the bottom packer. In the embodiment shown, the expansion cone driver222is activated by pumping fluid through the expansion cone driver, e.g., by connecting a top drive system to the side-entry sub207and pumping fluid through the side-entry sub into the pipe string204and through the connected expansion cone driver222. As fluid is pumped through the expansion cone driver222, the fluid fills and pressurizes the enclosed volume223below the expansion cone220. The pressurized enclosed volume223below the expansion cone220moves the expansion cone220upward (in a direction toward the surface of the well) through the eutectic expandable liner210. As the expansion cone220is moved upward through the eutectic expandable liner210, the expansion cone220pushes the wall of the eutectic expandable liner210radially outward, thereby deforming the liner wall to have an inner diameter approximately as large as the outer diameter of the expansion cone220. When the expansion cone220reaches an axial position along the eutectic expandable liner210having a bottom packer213, the expansion of the liner wall pushes the surrounding bottom packer213radially outward to contact and seal against the well wall, thereby setting the bottom packer213. After the bottom packer213is set, the heater221is activated (e.g., via electrical power provided through the wireline).

When the heater221is turned on, outer surfaces of the expansion cone220heated by the heater221heat the adjacent liner wall as the expansion cone pushes/expands the liner wall radially outward. In one or more embodiments, conductors may be incorporated through the expansion cone driver222, where the conductors are positioned along the expansion cone driver222to maintain electrical connectivity between the wireline plug209and the expansion cone heater221. In such manner, when the heater221is turned on and the expansion cone220is moved through the liner210, the heating expansion cone220both heats the liner wall and expands the liner wall radially outward in a single pass through the liner.

The heater221may be turned on after passing through a bottom packer213to avoid heating and damaging the bottom packer213. After passing through the section of the liner having the bottom packer213, the heater221may be turned on to heat the liner wall as the expansion cone passes through the eutectic alloy layer212section of the liner210. As the heating expansion cone220moves through the eutectic alloy layer212section of the liner210, the eutectic alloy layer212is heated from heat transfer through the liner wall from the heater221. Accordingly, heater(s) incorporated into the expansion cone220may be positioned along the expansion cone around or proximate to outer surfaces designed to contact the inner surface of the liner wall in order to improve heat transfer through the liner wall to the eutectic alloy layer212.

The heating may be controlled so as to heat the liner wall high enough to melt the surrounding eutectic alloy layer212. For example, in some embodiments, the expansion cone220(and incorporated heater221) may be pulled through the liner210at a calculated rate that allows sufficient heat to be transferred through the liner wall to melt the surrounding eutectic alloy layer212. In some embodiments, the amount of heat generated by heater(s) on an expansion cone may be controlled by turning on a selected number heaters around the expansion cone and/or by controlling the amount of heat output by a heater on the expansion cone. On/off control of heater(s) on an expansion cone and/or heat output level of heater(s) on an expansion cone may be controlled, for example, by an operator at the surface of the well, where surface commands may be transmitted via wireline to the heating system.

As the heated expansion cone220is moved through the section of the liner having the eutectic alloy layer212, the eutectic alloy layer212is melted by heat from the expansion cone heater221at the same time the expansion cone220is expanding the liner wall radially outward. The radially outward expansion of the liner pushes the molten eutectic alloy into the surrounding section of the well. For example, as shown inFIG.5, after the expansion cone220moves through the eutectic alloy layer212section of the liner, melting the eutectic alloy layer212and pushing the liner wall radially outward, the surrounding molten eutectic alloy is pushed into the well wall to seal the surrounding section of the well. There are two factors that contribute to the eutectic alloy setting in place as it is pushed into the well wall: 1) solidification happens immediately after the molten eutectic alloy is pushed into the well wall, similar to the solidification timeframe of soldering; and 2) the volume of the eutectic alloy may be calculated to which it fills the entire needed volume around the well wall.

When the heated expansion cone220has completely moved through the eutectic alloy layer212section of the liner, the heater221may be turned off. In some embodiments, as shown inFIG.5, a top packer214is provided around the liner on an axial side of the eutectic alloy layer212opposite the bottom packer213. In such embodiments, the heated expansion cone220continues to move through the expandable liner210(with the heater221on) until the expansion cone220reaches a portion of the liner having the top packer214, at which point the heater221is turned off. With the heater221off, the expansion cone220continues to move through the portion of the liner having the top packer214, thereby expanding the top packer214radially outward to contact and seal against the surrounding well wall.

As shown inFIG.5, when the expansion cone220has finished moving through the eutectic expandable liner210, the expanded liner is set and the surrounding section of the well is sealed. The heating expansion assembly (including the expansion cone220and the connected expansion cone driver222) may then be pulled out of the well after the expandable liner is set in the downhole location. In some embodiments, after the expandable liner is set and the pipe string with the connected heating expansion assembly is removed, subsequent well operations may be performed, such as running a bottom hole assembly through the well and through the set expandable liner to drill past the sealed downhole location.

The eutectic expandable liner and heating expansion assembly200may be sent downhole to seal and line a portion of a well for different reasons involving sealing fluid flow between the well and the surrounding formation. Additionally, eutectic expandable liner and heating expansion assemblies according to embodiments disclosed herein may be used to seal cased or uncased (open hole) portions of a well.

In the embodiment shown, the eutectic expandable liner and heating expansion assembly200is sent to a downhole location203in an open hole section of the well202having a loss zone205. A loss zone205may refer to a portion of the well in which fluid being circulated through the well is partially or totally lost through the loss zone into the formation. Thus, loss of circulation may physically be seen when the flow rate in the returns line from the well drops below the flow rate in lines pumping fluid into the well. There are degrees of loss of circulation that may be identified in a well based on the difference in the flow rates of fluid into and out of the well. For example, a total loss of circulation occurs when no return fluid reaches the surface following introduction of drilling fluid into the wellbore. A partial loss of circulation occurs when a predefined minimum amount of return fluid reaches the surface following introduction of drilling fluid into the wellbore. For example, a loss zone may be identified as a portion of the well in which fluid flows from the well into the formation at a rate of at least 10 bbls/hr.

According to embodiments of the present disclosure, prior to sending the eutectic expandable liner assembly downhole, the downhole location of a loss zone may be identified within an accuracy that is shorter than half the axial length of the eutectic alloy layer112provided on the eutectic expandable liner210. In some embodiments, after identifying a loss zone and prior to running the eutectic expandable liner assembly through the well, the axial length and thickness of the eutectic alloy layer112applied on the eutectic expandable liner110may be based on the predicted size of the loss zone.

Additionally, once the loss zone205is identified, an operator may prepare the well for a sealing operation by drilling beyond the identified loss zone205, deep enough to give enough space for the eutectic expandable liner and heating expansion assembly200to be positioned next to and seal the loss zone.

When a sealing operation is performed on a section of a well having a loss zone, such as shown inFIGS.2-5, the eutectic alloy layer212provided around the liner body may be designed to have sufficient size (e.g., thickness and axial length) to flow into the loss zone205when melted. As the molten eutectic alloy flows into the loss zone205, away from the heated expansion cone220, the eutectic alloy cools. Once the molten eutectic alloy cools to its eutectic temperature, the eutectic alloy resolidifies to seal the loss zone205.

Embodiments of the present disclosure may provide at least one of the following advantages. Commercially available expandable liner patches are typically made of steel, which is too strong to deform around obstacles behind it, e.g., cuttings or wellbore irregularities. Thus, when obstacles are present behind a conventional liner, an expansion cone running through the liner may not be able to push and expand the liner, but will instead push against the formation, which will stop the progress of the cone and fail the operation. However, by using eutectic expandable liners and heating expansion assemblies according to embodiments of the present disclosure, an outer layer of soft heated eutectic alloy would expand over obstacles, if any, while expanding the inner liner. Additionally, by using eutectic expandable liners and heating expansion assemblies according to embodiments of the present disclosure, the sealing process may be completed in a single run, where the eutectic liner is expanded and heated in a single pass of the expansion cone.

Although only a few example embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without materially departing from this invention. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims.