WO2023248157A1

WO2023248157A1 - Sealing tool for sealing fractures and method for the same

Info

Publication number: WO2023248157A1
Application number: PCT/IB2023/056424
Authority: WO
Inventors: Omar Mortagy; Ahmed Galal ABDEL-KADER; Shehab Ahmed
Original assignee: Omar Mortagy; Abdel Kader Ahmed Galal; Shehab Ahmed
Priority date: 2022-06-21
Filing date: 2023-06-21
Publication date: 2023-12-28

Abstract

Disclosed is sealing tool for sealing fractures in earth formation, comprises tubular outer tool body TOTB (207) wherein the TOTB comprises: outer side and inner side wall having slidable outer sleeve (212, SOS) and inner sleeves (216, SIS); restrictive element (218) arranged partly on inner side wall of TOTB; annular cavity (ACs) arranged at distance L1 from top surface of TOTB, and expandable sac(s) (222) to cover ACs, expandable sac(s) is coupled to TOTB via tube(s); hollow inner tool body (HITB), wherein the HITB comprises openings (228) for allowing flow of a sealing fluid therethrough, plug arrangement comprising first plug (230) and second plug (232), when pressure is applied on plug arrangement, movement of first plug is restricted by restrictive element while second plug slides downwards into HITB to slide SIS and SOS to slide downwards to, and ACs is exposed to release, PDVOSF into fractures.

Description

SEALING TOOL FOR. SEALING FRACTURES AND METHOD FOR THE SAME

TECHNICAL FIELD

The present disclosure relates to a sealing tool for sealing fractures. Moreover, the present disclosure relates to a method for sealing fractures. Moreover, the present disclosure relates to a sealing tool for sealing fractures. Moreover, the present disclosure relates to a sealing tool for sealing fractures. Moreover, the present disclosure relates to a sealing tool for sealing fractures.

BACKGROUND

Wellbore drilling operations are commonly conducted to drill various types of wells, such as those for oil, gas, water, and geothermal purposes. The drilling process involves the use of a rotating drill bit attached to a drill string that extends to a surface of the earth. The rotating drill bit is responsible for cutting or crushing the rock formations to facilitate the drilling of the wellbore.

Generally, during the drilling operation, the wellbore is typically filled with a circulating drilling fluid. Notably, the drilling fluid serves several purposes, including stabilizing the wellbore walls, transporting cuttings and rock chips to the surface, and cooling the drilling assembly. The drilling fluid is pumped through the central bore of the drill pipes and drilling assembly components, exiting through nozzles of the drill bit, and then circulating upward through an annulus between the wellbore walls and the drill string.

FIG. 1 (Prior Art) is a sectional view 100 of a large-size crack 102 in a rock formation 104 and lost circulation of a drilling fluid 106. Referring to FIG. 1 (Prior Art), a wellbore 108 is drilled through the rock formation 104 when it suddenly encounters a discontinuity or crack 102 in the rock formation 104 at which all drilling fluid 106 would escape instead of circulating up-hole in the annulus between the wellbore 108 and the drilling assembly. As soon as the loss of circulation is detected on surface, drilling is stopped. For wellbore safety reasons, drilling fluid 106 continues to be pumped through the annulus to prevent any potential well stability risks. The depth of the crack 102 is marked at which fluid circulation was lost. In such a case, there occurs a loss of a fluid column filling the wellbore, leading to a reduction in hydrostatic pressure and potential stability problems. Moreover, it poses a well control issue by increasing a risk of high-pressure gases or fluids escaping to the surface due to the absence of equalizing hydrostatic pressure.

Therefore, it is clear from FIG. 1 that existing drilling assembly has some focusing problems associated therewith. Notably, lost circulation material (LCM) particles have been employed along with the drilling fluid to block the fracture and restore the circulation of the drilling fluid. However, said LCM particles are not feasible for larger fractures as the LCM particles fail to effectively block the gap and continue to escape with the drilling fluid. In such cases, a cement plug is created to seal the wellbore below the fracture level. Additionally, a cement slurry is pumped to plug a portion of the wellbore and block a significant area of the fracture around the wellbore. Subsequently, the drilling process continues by drilling through the solidified cement plug, while the fracture remains sealed.

In some instances, conventional cement plug methods are insufficient to seal large fractures. The cement slurry continues to escape through the large fracture, preventing effective sealing. This may require multiple attempts to gradually tighten the fracture until it is completely sealed, resulting in significant time and cost losses.

Therefore, in light of the foregoing discussion, there exists a need to seal large fractures by overcoming the aforementioned drawbacks. SUMMARY

The aim of the present disclosure is to provide sealing tools and a method to seal large fractures in earth formation while drilling a wellbore. The aim of the present disclosure is achieved by a sealing tool and a method for sealing fractures in an earth formation as defined in the appended independent claims to which reference is made to. Advantageous features are set out in the appended dependent claims.

Throughout the description and claims of this specification, the words "comprise" , "include", "have", and "contain" and variations of these words, for example "comprising" and "comprises" , mean "including but not limited to", and do not exclude other components, items, integers or steps not explicitly disclosed also to be present. Moreover, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 (Prior Art) is an illustration of a sectional view of a large-size crack in a rock formation and lost circulation of a drilling fluid, in accordance with an embodiment of the present disclosure;

FIGs. 2A-F is an illustration of an environment depicting a use of a sealing tool for sealing fractures in an earth formation, in accordance with an embodiment of the present disclosure;

FIGs. 3A-E is an illustration of an environment depicting a use of a sealing tool for sealing fractures in an earth formation, in accordance with an embodiment of the present disclosure; FIGs. 4A-D is an illustration of an environment depicting a use of a sealing tool for sealing fractures in an earth formation, in accordance with an embodiment of the present disclosure;

FIGs. 5A-C is an illustration of an environment depicting a use of a sealing tool for sealing fractures in an earth formation, in accordance with an embodiment of the present disclosure; and

FIG. 6 is a flowchart depicting steps of a method for sealing fractures in an earth formation, in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

The following detailed description illustrates embodiments of the present disclosure and ways in which they can be implemented. Although some modes of carrying out the present disclosure have been disclosed, those skilled in the art would recognize that other embodiments for carrying out or practising the present disclosure are also possible.

In a first aspect, the present disclosure provides a sealing tool for sealing fractures in an earth formation, the sealing tool comprising: a tubular outer tool body configured to be deployed from a surface of the earth to a level of the fracture in the earth, wherein the tubular outer tool body comprises: an outer side wall having a slidable outer sleeve configured to at least partially line the tubular outer tool body from the outer side wall thereof; an inner side wall having a slidable inner sleeve configured to at least partially line the tubular outer tool body from the inner side wall thereof, wherein the slidable outer sleeve and the slidable inner sleeve are coupled; wall of the tubular outer tool body; at least one annular cavity arranged below the restrictive element and at least partly along the outer side wall at a distance LI from a top surface of the tubular outer tool body, and at least one expandable sac arranged inside the at least one annular cavity, configured to cover the at least one annular cavity, wherein the at least one expandable sac is coupled to the tubular outer tool body via at least one tube; a hollow inner tool body configured to contain a pre-defined volume of a sealing fluid, the hollow inner tool body comprising a plurality of openings for allowing the flow of the sealing fluid therethrough, a plug arrangement comprising a first plug and a second plug configured to move upwards and downwards inside the hollow inner tool body, wherein, when a pressure is applied on the plug arrangement, the movement of the first plug is restricted by the restrictive element of the tubular outer tool body while the second plug slides downwards into the hollow inner tool body to slide the slidable inner sleeve and the slidable outer sleeve to slide downwards to, and the at least one annular cavity is exposed to release, via the plurality of openings, the at least one tube and the at least one expandable sac, a part of the pre-defined volume of the sealing fluid from the hollow inner tool body into the fractures in the earth formation.

According to the first aspect of the present disclosure, there is provided the aforementioned sealing tool that is used to effectively seal the fractures in the earth formation while maintaining control over the flow of the sealing fluid and accommodating variations in fracture sizes. It will be appreciated that the aforementioned components of the sealing tool synergistically work together to achieve said advantages. In this regard, the sealing tool employs the tubular outer tool body for providing structural support to the sealing tool. The sealing tool employs the slidable outer sleeve and the slidable inner sleeve for allowing a smooth movement and providing a lining to the sealing tool body. The sealing tool employs the restrictive element for controlling the flow of the sealing fluid. The sealing tool possesses the annular cavity and the expandable sac below the restrictive element for sealing the fracture in the earth formation. The sealing tool comprises the hollow inner tool body having the plurality of openings and the plug arrangement for facilitating a controlled release of the sealing fluid into the at least one expandable sac.

In a second aspect, the present disclosure provides a method for sealing fractures in an earth formation, the method comprising: method for sealing fractures in an earth formation, the method comprising: identifying a location of the fracture in the earth formation; arranging a sealing tool in a wellbore such that the sealing tool is adjacent to the fracture; filling a pre-defined volume of a sealing fluid in an expandable sac under pressure; allowing the sealing fluid to solidify; detaching a deployment tool of sealing tool and drilling through the excess sealing fluid and attached components therewith.

The second aspect of the method offers advantages such as precise targeting of fractures, controlled sealing fluid flow through the plug arrangement and restrictive element, an efficient sealing tool design with slidable sleeves and expandable sacs, versatility in choosing sealing fluids, and enhanced sealing performance. These features synergistically work together to ensure accurate and controlled delivery of the sealing fluid to the fractures, optimizing the sealing process and improving overall sealing effectiveness.

In a third aspect, the present disclosure provides a sealing tool for sealing fractures in an earth formation, the sealing tool comprising: a tubular tool body configured to be deployed from a surface of the earth to a level of the fracture in the earth, wherein the tubular tool body is configured to contain a pre-defined volume of a sealing fluid, the tubular tool body comprises: a side wall having: at least one opening for allowing the flow of the sealing fluid therethrough; and at least one slidable sleeve configured to at least partially line the at least one opening of the tubular tool body; a restrictive element arranged at least partly on the side wall of the tubular tool body; a plug arrangement comprising a first plug and a second plug configured to move upwards and downwards inside the tubular tool body, at least one sealing element arranged outside the at least one opening, and attached at one side to a fixed collet and at the other side to a sliding collet.; wherein when a pressure is applied on the plug arrangement the movement of the first plug is restricted by the restrictive element of the tubular tool body while the second plug slides downwards to slide the slidable at least one sleeve downwards, to expose the at least one opening to release, via the at least one sealing element that , a part of the pre-defined volume of the sealing fluid from the tubular tool body into the fractures in the earth formation. In a fourth aspect, the present disclosure provides a sealing tool for sealing fractures in an earth formation, the sealing tool comprising: a hole enlarging tool configured to enlarge a portion of a wellbore surrounding the fracture; a fracture-sealing assembly comprising: an inflatable element tightly wrapped around an external sleeve; a deployment tool attached to the external sleeve, the deployment tool being detachable from the external sleeve; a packer positioned at a distance above the deployment tool; a pump configured to pump a sealing fluid through the deployment tool to inflate the inflatable structure and seal off the fracture; a drilling assembly comprising a drilling reamer configured to drill through the external sleeve and the inflatable element to clear the wellbore for further drilling operations.

In a fourth aspect, the present disclosure provides a sealing tool implemented as a drilling tool for sealing a fracture in an earth formation, the sealing tool comprising: a drill-bit attached to a lowest extremity of a drill-string; a hole enlarging tool configured to enlarge a portion of the wellbore surrounding the fracture upon encountering and detecting the fracture; a deployment tool; an inflatable structure wrapped around a sleeve, the inflatable structure being directly attached to the deployment tool or wrapped around the sleeve; a drilling reamer positioned at a short distance above the deployment tool; a packer positioned at a certain distance above the deployment tool; a pump configured to pump a liquid substance capable of solidifying to inflate the inflatable structure and seal off the fracture; a sealing fluid path through the deployment tool for allowing drilling fluid to flow to the drill-bit.

Throughout the present disclosure, the term "sealing tool" as used herein refers to a device that is used for sealing fractures in the earth formation. The term "fracture" as used herein refers to a discontinuity or crack in a rock formation of the earth. Notably, the fracture is a type of geological feature having a break or separation in the rock, creating a semi-planar cavity or gap. Optionally, the fractures could vary in size and shape. Optionally, the fracture could occur naturally or be induced during a drilling operation or other geological activity. In this regard, the fractures are discontinuities that create cavities surrounding a wellbore.

The sealing tool comprises the tubular outer tool body that is designed to be deployed from the surface of the earth to the level of the fracture that requires sealing. It will be appreciated that the tubular outer tool body serves as a housing of the sealing tool and provides support and functionality within the sealing tool.

Optionally, the tubular outer tool body is fabricated using a drillable material. Herein, the term drillable material refers to a substance or a material that can be easily drilled, cut, or modified using a drilling tool. It will be appreciated that the drillable material possesses properties that allow the drillable material to be penetrated or shaped with relative ease using drilling processes. Optionally, the drillable materials are typically selected based on a composition, hardness, and compatibility thereof with drilling techniques. Beneficially, the drillable materials enable efficient drilling operations, facilitating the creation of holes, cavities, or modifications while manufacturing the tubular outer tool body of the sealing tool. Optionally, the drillable material is an aluminium. Notably, the aluminium could be easily drilled or modified during the deployment or installation process, thus considered suitable for fabricating the tubular outer tool body.

The tubular outer tool body of the sealing tool comprises the outer side wall that is equipped with a slidable outer sleeve that can move along the outer side wall. In this regard, the slidable outer sleeve is used to cover and at least partially line the tubular outer tool body, thereby providing a protective and sealing function. Beneficially, the slidable outer sleeve allows for smooth movement along the outer side wall of the tubular outer tool body.

The tubular outer tool body of the sealing tool comprises the inner side wall having the slidable inner sleeve that could slide along the inner side wall. In this regard, the slidable outer sleeve and the slidable inner sleeve are connected or coupled together. It will be appreciated that the slidable outer sleeve and the slidable inner sleeve works in conjunction with each other to ensure a synchronized movement thereof. Optionally, the slidable outer sleeve and the slidable inner sleeve allows for effective sealing of the fractures by maintaining alignment and preventing any misalignment or leakage between the slidable outer sleeve and the slidable inner sleeves.

Optionally, the tubular outer tool body further comprises one or more openings extending from the inner side wall to the outer side wall of the tubular outer tool body. Herein, the term "one or more openings" refers to the presence of at least one or multiple apertures or passages within an object. In this regard, the one or more openings allows for the establishment of a fluid flow pathway between the inner and outer side walls of the tubular outer tool body. Optionally, the one or more openings may serve as channels for pressure equalization between the inner and outer side walls of the tubular outer tool body. The pressure equalization helps to balance the pressure exerted on the tubular outer tool body, ensuring stability and preventing potential damage or failure of the sealing tool. Optionally, the one or more openings provides flexibility in the design and functionality of the sealing tool. It allows for customization based on specific requirements, such as controlling the flow rate, or incorporating additional tools or components therethrough.

Optionally, the sealing tool further comprises a locking arrangement configured for locking the slidable outer sleeve and the tubular outer tool body, wherein the locking arrangement is selected from at least one of: one or more shear pins, one or more shear rings, one or more fasteners or one or more nuts and bolts. The term "locking arrangement" as used herein refers to a mechanism or system designed to secure and immobilize two or more components together, preventing unintended movement or separation thereof. In this regard, the locking arrangement is used to lock the slidable outer sleeve to the tubular outer tool body. Optionally, the locking arrangement is one or more shear pins. Herein, the one or more shear pins refer to mechanical devices that are designed to break under a predetermined load, providing a temporary or sacrificial locking mechanism that prevents unintended movement or separation of the slidable outer sleeve and the tubular outer tool body. Optionally, the locking arrangement is one or more shear rings. Herein, the one or more shear rings refer to circular components that are designed to fracture or deform under a specific force, creating a locking effect between the slidable outer sleeve and the tubular outer tool body. Optionally, the one or more shear rings provide a reliable and easily replaceable locking mechanism.

Optionally, the locking arrangement is one or more fasteners that are hardware components. In this regard, the one or more fasteners could be tightened or loosened as needed to securely fasten the slidable outer sleeve to the tubular outer tool body. In an example, the fastener may be a screw. Optionally, the locking arrangement is one or more nuts and bolts. In this regard, by threading a bolt through a hole in the slidable outer sleeve and securing it with a nut on the other side of the tubular outer tool body, this combination provides a strong and durable locking mechanism, ensuring the stability of the sealing tool. Advantageously, the presence of the locking arrangement allows for easy maintenance and replacement of the slidable outer sleeve when needed, thereby facilitating inspections, repairs, or the installation of a new slidable outer sleeve.

The term "expandable sac" as used herein refers to a reservoir or storage area that is designed to accommodate the sealing fluid or any other desired substance that is used to seal fractures in the earth formation. In this regard, when the sealing tool is deployed and the pressure is applied, the expandable sac expands or inflates, covering the annular cavity and releasing the sealing fluid into the fractures. Optionally, the at least one expandable sac is a cylindrical rubber or a fabric membrane that is positioned between the fixing collet and the sliding collet.

Optionally, the at least one expandable sac is made of a cylindrical rubber or fabric membrane, that could stretch or expand in response to the pressure exerted thereon. Said expansion allows the at least one sac to effectively distribute the sealing fluid and ensure the proper deployment thereof in the desired locations. It will be appreciated that the at least one expandable sac release the sealing fluid in a controlled manner, contributing to the overall sealing performance of the sealing tool.

Optionally, the at least one expandable sac is fabricated using at least one of: a rubber, a fiber fabric, a polymer, an elastomer or a flexible material. In this regard, optionally, the at least one expandable sac is fabricated using the rubber that offers excellent elasticity and resilience. It will be appreciated that the rubber allows the expansion and the contraction of the at least one expandable sac during the sealing process. Optionally, the rubber provides a tight and reliable seal, ensuring effective containment and distribution of the sealing fluid. Optionally, the at least one expandable sac is fabricated using the fiber fabric, such as a woven or a non-woven textile material, to provide strength and durability thereto. Typically, the fiber fabrics possesses a high tensile strength and tear resistance, that could be beneficial in maintaining the integrity of the at least one expandable sac under pressure. Additionally, the porous nature of some fiber fabrics allows for controlled permeability, facilitating the release and distribution of the sealing fluid. Optionally, the at least one expandable sac is fabricated using the polymer material that offers versatility and customization options. Optionally, polymers could be engineered to possess specific properties such as flexibility, chemical resistance, and dimensional stability. The choice of polymer can be tailored to meet the specific requirements of the sealing tool, ensuring optimal performance and longevity.

Optionally, the at least one expandable sac is fabricated using the elastomers, which are elastic polymers, provide excellent flexibility and deformation recovery characteristics. Optionally, utilizing the elastomer for the at least one expandable sac allows for repeated expansion and contraction without losing its original shape or functionality. Optionally, the elastomers offer good sealing properties and can withstand various environmental conditions, making them suitable for sealing applications.

Optionally, the at least one expandable sac is fabricated using the flexible materials that could include a wide range of materials such as silicone, synthetic rubber, or other similar substances, offering adaptability and ease of manipulation. Optionally, the flexible materials could conform to irregular shapes and surfaces, ensuring a tight and effective seal.

It will be appreciated that the selection of an appropriate material for the at least one expandable sac ensures reliable containment and controlled release of the sealing fluid, contributing to the success of the sealing process and the longevity of the sealing tool.

The term "restrictive element" refers to a physical barrier or obstruction that is positioned on the inner side wall of the tubular outer tool body. In this regard, the restrictive element may extend partially or completely along the inner side wall, depending on the specific design and requirements of the sealing tool. Optionally, the restrictive element could be implemented as a protrusion, ledge, or any other suitable structure that interacts with the first plug (described later in the description) during the operation of the sealing tool.

Herein, the term "annular cavity" refers to a circular or ring-shaped void or space within the sealing tool body. In this regard, the annular cavity is positioned below the restrictive element, meaning it is situated closer to the bottom of the sealing tool body than the restrictive element is. Moreover, the annular cavity is also partially aligned along the outer side wall, extending along a portion of its circumference. Furthermore, the distance between the top surface of the tubular outer tool body and the annular cavity is denoted as LI. Optionally, the distance LI represents a vertical separation or height between the top surface and the annular cavity. Optionally, the distance LI could vary depending on the specific design and requirements of the sealing tool.

Optionally, the annular cavity may serve as a reservoir or space for accommodating certain components or materials necessary for the operation of the sealing tool. In particular, the annular cavity is associated with the storage and expansion of the at least one expandable sac that is intended to cover the annular cavity. Moreover, the expandable sacs, that are connected to the tubular outer tool body via at least one tube, are designed to expand and contract based on the fluid pressure exerted thereon. Optionally, the annular cavity provides a confined area for the at least one expandable sacs to be housed and operated within.

Optionally, the sealing tool further comprises a fixing collet and a sliding collet associated with the slidable outer sleeve, wherein the at least one expandable sac is arranged between the fixing collet and the sliding collet. The term "fixing collet" as used herein refers to a collar-like component that surrounds and clamps onto an object being held or secured. In this regard, the fixing collet creates a strong clamping force around the object, exerting pressure to firmly hold it in place. Optionally, the sealing tool comprises the fixing collet to hold both a workpiece and the sealing tool, providing a stable and secure connection. Both the fixed collet and the sliding collets are attached at the ends of the cylindrical rubber membrane. The fixed collet is a pivot point to provide positioning of the membrane. When the membrane is inflated, if both ends are fixed, it will be under very high tension due to inflation, so the sliding collet gives one degree of freedom allowing the membrane to get shorter as it gets inflated, so as to minimize the stresses in the membrane.

The term "sliding collet" refers to a collet that has the ability to slide or move along an axis while maintaining contact with the surrounding components. Optionally, the sliding collet acts as a bearing and allows for movement or adjustment of the sleeve within the limited workspace. Optionally, the sliding collet is chosen specifically for its ability to handle heavy loads and provides one degree of freedom, allowing the at least one expandable sac to adjust its length as it inflates to minimize stresses. Optionally, the fixing collet and the sliding collet are attached at the two ends of the cylindrical rubber membrane. Optionally, the fixing collet serves as a pivot point to provide positioning of the membrane, while the sliding collet allows for flexibility and accommodation of variations during the inflation process. Together, they contribute to the effective sealing and reliable performance of the tool.

The sealing tool comprises the hollow inner tool body having an empty space or void inside. The term "pre-defined volume" refers to a specific quantity or amount of sealing fluid that is predetermined or specified for use in the sealing tool. In this regard, the pre-defined volume could vary depending on the requirements of the sealing operation and the size of the fractures to be sealed. Optionally, the sealing fluid is a cement or a resin. Notably, the cement is a powdered substance that, when mixed with water, forms a thick paste that hardens and sets over time. It will be appreciated that the cement offers excellent mechanical strength and durability, making it suitable for sealing and stabilizing fractures in the earth formation. Typically, the resin is a type of synthetic material that could be in liquid or solid form. It will be appreciated that the resins are often used as sealing fluids in applications where flexibility, adhesion, and chemical resistance are required. Optionally, the resins could be designed to cure or harden in response to temperature, pressure, or other curing agents.

The hollow inner tool body comprises the plurality of openings for allowing the flow of the sealing fluid therethrough. In this regard, during the drilling operation, the sealing fluid is provided to the hollow inner tool body. The plurality of openings act as pathways or channels for the sealing fluid to move within the sealing tool body. The number and arrangement of the plurality of openings could vary depending on the design and requirements of the sealing tool. The plurality of openings facilitates the controlled release and distribution of the sealing fluid from the hollow inner tool body.

The hollow inner tool body comprises the plug arrangement within the sealing tool. The plug arrangement consists of a first plug and a second plug that are designed to move upwards and downwards inside the hollow inner tool body. In this regard, when the pressure is applied to the plug arrangement, specific actions and interactions occur. The first plug and the second plug are positioned within the hollow inner tool body and are capable of vertical movement. Moreover, when the pressure is exerted on the plug arrangement, the movement of the first plug is restricted by the restrictive element of the tubular outer tool body. The restriction prevents the first plug from moving upwards. Furthermore, the second plug is allowed to slide downwards into the hollow inner tool body when pressure is applied to the plug arrangement. As the second plug moves downwards, it initiates the sliding motion of the slidable inner sleeve and slidable outer sleeve. The slidable inner sleeve and slidable outer sleeve are components that line the tubular outer tool body and are designed to slide downwards in response to the movement of the second plug. The downward motion of the slidable inner sleeve and slidable outer sleeve, induced by the movement of the second plug, facilitates the desired deployment and activation of the sealing mechanism.

Furthermore, once the annular cavity is exposed, a portion of the predefined volume of sealing fluid contained within the hollow inner tool body is released. The release occurs through the plurality of openings that are present in the hollow inner tool body. The sealing fluid flows through the plurality of openings, as well as through the at least one tube and the at least one expandable sac, into the fractures in the earth formation.

Optionally, the sealing tool further comprises a plurality of one-way flow valves configured to prevent the sealing fluid from escaping the at least one expandable sac. In this regard, the one-way flow valves are designed to allow fluid flow in only one direction, specifically to prevent the sealing fluid from escaping the at least one expandable sac. Optionally, the oneway flow valves ensure that once the sealing fluid enters the at least one expandable sac, it could not flow back or escape through the same pathway. Instead, the sealing fluid is retained within the at least one expandable sac, maintaining an intended purpose thereof sealing the fractures in the earth formation. The technical effect of incorporating oneway flow valves is to enhance the efficiency and effectiveness of the sealing process by preventing the sealing fluid from escaping and minimizing wastage of the sealing fluid.

Optionally, the sealing tool further comprises a hole enlarging element and configured for enlarging at least a portion around the fracture in the earth formation. Herein, the hole enlarging element refers to an additional component specifically designed to serve the purpose of creating a larger opening or cavity around the fracture area. Optionally, the hole enlarging element could be designed in various forms such as cutting blades, reaming devices, or mechanical expanders. Optionally, when activated, the hole enlarging element widens the hole or cavity surrounding the fracture, providing more space for the sealing process.

The technical effect of incorporating the hole enlarging element is that by enlarging the hole or cavity, the sealing tool ensures that the sealing fluid can adequately fill the space, enhancing the sealing performance and reducing the likelihood of incomplete or ineffective sealing.

Optionally, the sealing tool further comprises a packer and configured to isolate the pressure of at least the portion of the wellbore where the fracture exists. Herein, the packer refers to a mechanical device used in wellbore operations to create a seal or barrier between different zones or sections of the wellbore. Optionally, the packer is a standard tool used in the oil and gas drilling field. Optionally, the packer is mainly composed of an elastomeric part that can be enlarged hydraulically or mechanically to be compressed against the earth formation, in case of open-hole packers, or the casing, in case of casing packers, to seal off or isolate a certain zone of the wellbore. In this regard, the packer is configured to isolate the pressure in the portion of the wellbore where the fracture, that is being sealed, exists. Optionally, by isolating the pressure, the packer helps maintain the desired pressure conditions within the sealed portion of the wellbore where the fracture exists. The controlled pressure environment contributes to the effectiveness of the fracture sealing process, as it ensures that the pressure all around the sealing tool remains the same before, during, and even after the sealing process has been completed.. The technical effect of incorporating the packer into the sealing tool is to protect the soft material of the sealing tool against damage and to enhance the sealing performance by providing pressure isolation and control. This contributes to a more safe, stable and reliable sealing process, allowing the sealing fluid to properly set and harden, ultimately improving the effectiveness and durability of the seal.

Optionally, the sealing tool further comprises a drilling reamer for removing the excess sealing fluid from a wellbore. Herein, the drilling reamer refers to a mechanical tool used in drilling operations. Optionally, the drilling reamer consists of cutting or scraping elements associated with the sealing tool's body. Optionally, the drilling tool is either a complete separate assembly lowered into the wellbore after the sealing process as in the standard sealing tool, or the drilling reamer located above the sealing tool. Optionally, the purpose of the drilling reamer is to enlarge or smooth the wellbore, remove obstructions, and clean out debris generated during the drilling operation. Optionally, the drilling reamer is arranged in a position where the drilling reamer could access the wellbore after the sealing process is completed. Optionally, the drilling reamer could be arranged near a bottom of the sealing tool or at a suitable location that allows effective removal of excess sealing fluid.

The technical effect of including the drilling reamer in the sealing tool is to ensure the removal of any excess sealing fluid from the wellbore. During the sealing process, it is common for some of the sealing fluid to escape into the wellbore or accumulate in undesirable locations. The excess sealing fluid could hinder subsequent operations and may impact the overall effectiveness of the sealing.

The present disclosure also relates to the method for sealing fractures in an earth formation as described above. Various embodiments and variants disclosed above, with respect to the aforementioned sealing tool for sealing fractures in an earth formation, apply mutatis mutandis to the method for sealing fractures in an earth formation.

The present disclosure also relates to the sealing tool for sealing fractures in an earth formation as described above. Various embodiments and variants disclosed above, with respect to the aforementioned sealing tool for sealing fractures in an earth formation, apply mutatis mutandis to the sealing tool for sealing fractures in an earth formation.

It will be appreciated that the sealing tool of the third aspect is an alternative of the sealing tool of the first aspect. Herein, the sealing tool of the third aspect does not contain an annular cavity created by the presence of the hollow inner tool body as in the first aspect. The tubular tool body is itself a hollow tubular tool body having a side wall an inner diameter of which is smaller than an outer diameter thereof; and a covered base to create a pre-defined volume of the tubular tool body. The sealing tool of the third aspect is configured to be deployed from the surface of the earth to the level of the fracture in the earth in a similar way as the sealing tool of the first aspect. The hollow tubular tool body is configured to contain a pre-defined volume of a sealing fluid therein. The side wall of the tubular tool body has at least one opening for allowing the flow of the sealing fluid therethrough; and at least one slidable sleeve configured to at least partially line the at least one opening of the tubular tool body. In an embodiment, the at least one slidable sleeve may be fixed at one of the openings from amongst the at least one slidable opening. The at least one sealing element is arranged outside the at least one opening in an orthogonal or angular position. The at least one sealing element may be implemented as a cylindrical rubber tube to allow a part of the pre-defined volume of the sealing fluid passing from the volume of the tubular tool body to flow in to the fracture in the earth formation via the at least one opening when a pressure is applied on the plug arrangement.

Optionally, the at least one sealing element is implemented as a cylindrical rubber tube, and wherein a diameter of the at least one sealing element has a diameter corresponding to the diameter of the at least one opening. Beneficaially, equal diameters of the said structures allow a constant flow of the sealing fluid therethrough. The present disclosure also relates to the sealing tool for sealing fractures in an earth formation as described above. Various embodiments and variants disclosed above, with respect to the aforementioned sealing tool for sealing fractures in an earth formation, apply mutatis mutandis to the sealing tool for sealing fractures in an earth formation.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring to FIGs. 2A-F illustrated is an environment 200 depicting a use of a sealing tool 202 for sealing fractures 204 in an earth formation 206, in accordance with an embodiment of the present disclosure. As shown, the sealing tool 202 is deployed all the way from the surface to the level of the fracture 204. The sealing tool 202 comprises a tubular outer tool body 207 configured to be deployed from a surface 208 of the earth to a level of the fracture 204 in the earth, wherein the tubular outer tool body 207 comprises an outer side wall 210 having a slidable outer sleeve 212 configured to at least partially line the tubular outer tool body 207 from the outer side wall 210 thereof; an inner side wall 214 having a slidable inner sleeve 216 configured to at least partially line the tubular outer tool body 207 from the inner side wall 214 thereof, wherein the slidable outer sleeve 212 and the slidable inner 216 sleeve are coupled; a restrictive element 218 arranged at least partly on the inner side wall 214 of the tubular outer tool body 207 ; at least one annular cavity 220 arranged below the restrictive element 218 and at least partly along the outer side wall 210 at a distance LI from a top surface of the tubular outer tool body 207, and at least one expandable sac 222 arranged inside the at least one annular cavity 220, configured to cover the at least one annular cavity 220, wherein the at least one expandable sac 222 is coupled to the tubular outer tool body 207 via at least one tube 224; a hollow inner tool body 226 configured to contain a predefined volume of a sealing fluid, the hollow inner tool body comprises a plurality of openings 228 for allowing the flow of the sealing fluid therethrough, a plug arrangement comprising a first plug 230 and a second plug 232 configured to move upwards and downwards inside the hollow inner tool body 226, wherein, when a pressure is applied on the plug arrangement, the movement of the first plug 230 is restricted by the restrictive element 218 of the tubular outer tool body 207 while the second plug 232 slides downwards into the hollow inner tool body to slide the slidable inner sleeve 216 and the slidable outer sleeve 212 to slide downwards to, and the at least one annular cavity 220 is exposed to release, via the plurality of openings 228, the at least one tube 224 and the at least one expandable sac 222, a part of the pre-defined volume of the sealing fluid from the hollow inner tool body into the fractures 204 in the earth formation 206.

Optionally, the sealing tool 202 further comprises a plurality of one-way flow valves 234 configured to prevent the sealing fluid from escaping the at least one expandable sac 222. There is also shown a wellbore 233.

Referring to FIGs. 3A-E illustrated is an environment 300 depicting a use of a sealing tool 302 for sealing fractures 304 in an earth formation 306, in accordance with another embodiment of the present disclosure. As shown in FIG. 3A, optionally, the sealing tool 302, further comprises a fixing collet 308 and a sliding collet 310 associated with the slidable outer sleeve 312, wherein the at least one expandable sac 314 is arranged between the fixing collet 308 and the sliding collet 310. As shown in FIG. 3B, a first plug 312 and a second plug 314 run through the inner surface of the sealing tool 302 followed by a sealing fluid pumped from surface. The first plug 312 lands on a restriction 316 in the tubular outer tool body 318, while the second plug 314 continues to land on the inner sleeve 320. As shown in FIG. 3C, upon applying pressure, the first plug 312 would cause the inner sleeve 320 to slide down to a lower position. As the inner sleeve 320 and slides down, the inner sleeve 320 would uncover a plurality of openings 322 allowing cement or resin slurry to flow through the plurality of openings 322 then through one-way valves 324 to start pressurizing the small volume between outer sleeve 312 and the at least one expandable sac 314. As the at least one expandable sac 314 starts to expand, it pulls the upper sliding collet 310 causing it to slide down allowing for more volume to be filled between the outer sleeve 312 and the at least one expandable sac 314.

Referring to FIGs. 4A-D illustrated is an environment 400 depicting a use of a sealing tool 402 for sealing fractures 404 in an earth formation 406, in accordance with another embodiment of the present disclosure. As shown in FIG. 4A, a hole section around the fracture 404 has been enlarged using a hole enlargement tool. Then, when the hole enlargement tool is withdrawn the sealing tool 402 is run in the fractures 404. Optionally, the sealing tool 402 comprises at least one expandable sac 408 surrounding or tightly wrapped around a deployment tool 410. Optionally, the sealing tool 402 may also include a packer 412 at a certain distance above the deployment tool 410. When the sealing tool 402 reaches the fracture 404 location, packer 412 is set. As shown in FIG. 4B, a sealing fluid 414, or any other liquid substance that is capable of solidifying with time, pressure, or temperature, is then pumped from surface to flow through the deployment tool 410, and enter at least one expandable sac 408 to inflate the at least one expandable sac 408 inside the enlarged hole section 412 to seal off the fracture 404. As shown in FIG. 4C, deployment tool 410 is then withdrawn. As shown in FIG. 4D, a zoomed view of the deployment tool 410. As shown, a bore of external sleeve 412 concentrically comprises body 414 fixed together via shear pins such as 416. Body 414 is a cylindrical structure that houses in its bore 418 another cylindrical structure, called mandrel 420, which is allowed to slide along the axis of body 414. Mandrel 420 may be fixed to body 414 via shear pins such as 416. Referring to FIGs. 5A-C illustrated is an environment 500 depicting a use of a sealing tool 502 for sealing fractures 504 in an earth formation, in accordance with another embodiment of the present disclosure. As shown, the sealing tool 502 comprises a drill-bit 504 at the lowest extremity of the drill-string, a hole enlarging tool 506, a drilling fractureseal tool that consists of a deployment tool 508, at least one expandable sac 510, a drilling reamer 512 at a short distance above the deployment tool 508, and packer 514 positioned at a certain distance above the deployment tool 508. The at least one expandable sac 510 can be directly attached to deployment tool 508. A sleeve 516 is attached to deployment tool 508 via shear pins or via any other means. As soon as the fracture 504 is encountered and detected at surface, hole enlarging tool 506 is activated and the portion of hole around the fracture 504 is enlarged to a certain diameter. After hole portion has been enlarged, hole enlarging tool 506 is deactivated. Packer 514 is then set. Cement or resin 518, or any other liquid substance that is capable of solidifying with time, pressure, or temperature, is then pumped from surface to inflate the at least one expandable sac 510 inside the enlarged section to seal off the crack, as shown in figure 5B. The resin 518 or cement is allowed a certain duration to completely set and solidify. After setting, packer 514 is deactivated, and a drilling fluid path through the deployment tool 508 is re-opened to allow drilling fluid to flow again from surface to the drill-bit. Rotation of the drill-string is restarted and the drill-string is lowered to allow drilling-reamer 512 to drill through sleeve 516 and through the excess of solidified resin 518 or cement, as shown in figure 5C.

Referring to FIG. 6, illustrated is a flowchart depicting steps of a method for sealing fractures in an earth formation, in accordance with an embodiment of the present disclosure. At step 602, a location of the fracture is identified in the earth formation. At step 604, a sealing tool is arranged in a wellbore such that the sealing tool is adjacent to the fracture. At step 606, a pre-defined volume of a sealing fluid is filled in at least one expandable sac . At step 608, a sealing fluid is left to sit. At step 610, a deployment tool is detached and drilled through an excess sealing fluid and attached components therewith. The aforementioned steps are only illustrative and other alternatives can also be provided where one or more steps are added, one or more steps are removed, or one or more steps are provided in a different sequence without departing from the scope of the claims herein.

Claims

1. A sealing tool for sealing fractures in an earth formation, the sealing tool comprising : a tubular outer tool body configured to be deployed from a surface of the earth to a level of the fracture in the earth, wherein the tubular outer tool body comprises: an outer side wall having a slidable outer sleeve configured to at least partially line the tubular outer tool body from the outer side wall thereof; an inner side wall having a slidable inner sleeve configured to at least partially line the tubular outer tool body from the inner side wall thereof, wherein the slidable outer sleeve and the slidable inner sleeve are coupled; a restrictive element arranged at least partly on the inner side wall of the tubular outer tool body; at least one annular cavity arranged below the restrictive element and at least partly along the outer side wall at a distance LI from a top surface of the tubular outer tool body, and at least one expandable sac arranged inside the at least one annular cavity, configured to cover the at least one annular cavity, wherein the at least one expandable sac is coupled to the tubular outer tool body via at least one tube; a hollow inner tool body configured to contain a pre-defined volume of a sealing fluid, the hollow inner tool body comprising a plurality of openings for allowing the flow of the sealing fluid therethrough, a plug arrangement comprising a first plug and a second plug configured to move upwards and downwards inside the hollow inner tool body, wherein, when a pressure is applied on the plug arrangement, the movement of the first plug is restricted by the restrictive element of the tubular outer tool body while the second plug slides downwards into the hollow inner tool body to slide the slidable inner sleeve and the slidable outer sleeve to slide downwards to, and the at least one annular cavity is exposed to release, via the plurality of openings, the at least one tube and the at least one expandable sac, a part of the pre-defined volume of the sealing fluid from the hollow inner tool body into the fractures in the earth formation.

2. The sealing tool of claim 1, further comprises a plurality of one-way flow valves configured to prevent the sealing fluid from escaping the at least one expandable sac.

3. The sealing tool of claim 1, wherein the at least one expandable sac is fabricated using at least one of: a rubber, a rubber-coated fabric, a fiber fabric, a polymer, an elastomer or a flexible material.

4. The sealing tool of claim 1, wherein the sealing fluid is a cement or a resin.

5. The sealing tool of claim 1, wherein at least the tubular outer tool body is fabricated using a drillable material.

6. The sealing tool of claim 1, further comprises a locking arrangement configured for locking the slidable outer sleeve and the tubular outer tool body, wherein the locking arrangement is selected from at least one of: one or more shear pins, one or more shear rings, one or more fasteners or one or more nuts and bolts.

7. The sealing tool of claim 1, further comprises a fixing collet and a sliding collet associated with the slidable outer sleeve, wherein the at least one expandable sac is arranged between the fixing collet and the sliding collet.

8. The sealing tool of claim 1, wherein the tubular outer tool body further comprises one or more openings extending from the inner side wall to the outer side wall of the tubular outer tool body.

9. The sealing tool of claim 1, further comprises a hole enlarging element and configured for enlarging at least a portion around the fracture in the earth formation.

10. The sealing tool of claim 1, further comprises a packer and configured to isolate the pressure of at least the portion of the fracture.

11. The sealing tool of claim 1, further comprises a drilling reamer for removing the excess sealing fluid from a wellbore.

12. A method for sealing fractures in an earth formation, the method comprising : identifying a location of the fracture in the earth formation; arranging a sealing tool in a wellbore such that the sealing tool is adjacent to the fracture; filling a pre-defined volume of a sealing fluid in an expandable sac under pressure; allowing the sealing fluid to solidify; detaching a deployment tool of sealing tool and drilling through the excess sealing fluid and attached components therewith.

13. A sealing tool for sealing fractures in an earth formation, the sealing tool comprising: a tubular tool body configured to be deployed from a surface of the earth to a level of the fracture in the earth, wherein the tubular tool body is configured to contain a pre-defined volume of a sealing fluid, the tubular tool body comprises: a side wall having: at least one opening for allowing the flow of the sealing fluid therethrough; and at least one slidable sleeve configured to at least partially line the at least one opening of the tubular tool body; a restrictive element arranged at least partly on the side wall of the tubular tool body; a plug arrangement comprising a first plug and a second plug configured to move upwards and downwards inside the tubular tool body, at least one sealing element arranged outside the at least one opening, and attached at one side to a fixed collet and at the other side to a sliding collet.; wherein when a pressure is applied on the plug arrangement the movement of the first plug is restricted by the restrictive element of the tubular tool body while the second plug slides downwards to slide the slidable at least one sleeve downwards, to expose the at least one opening to release, via the at least one sealing element that , a part of the pre-defined volume of the sealing fluid from the tubular tool body into the fractures in the earth formation.

14. The sealing tool of claim 13, wherein the at least one sealing element is implemented as a cylindrical rubber tube.

15. A sealing tool for sealing fractures in an earth formation, the sealing tool comprising: a hole enlarging tool configured to enlarge a portion of a wellbore surrounding the fracture; a fracture-sealing assembly comprising: an inflatable element tightly wrapped around an external sleeve; a deployment tool attached to the external sleeve, the deployment tool being detachable from the external sleeve; a packer positioned at a distance above the deployment tool; a pump configured to pump a sealing fluid through the deployment tool to inflate the inflatable structure and seal off the fracture; a drilling assembly comprising a drilling reamer configured to drill through the external sleeve and the inflatable element to clear the wellbore for further drilling operations.

16. The sealing tool of claim 13, wherein the hole enlarging tool is part of a drill-string used to drill the wellbore.

17. The sealing tool of claim 13, the packer is at least one of: a hydraulic packer, a mechanical packer.

18. The sealing tool of claim 13, wherein the inflatable structure is inflated by applying pressure to a mandrel slidably housed within a bore of the external sleeve.

19. The sealing tool of claim 13, further comprising a plurality of shear pins for attaching the external sleeve to the deployment tool and the mandrel to the body of the external sleeve.

20. A sealing tool implemented as a drilling tool for sealing a fracture in an earth formation, the sealing tool comprising: a drill-bit attached to a lowest extremity of a drill-string; a hole enlarging tool configured to enlarge a portion of the wellbore surrounding the fracture upon encountering and detecting the fracture; a deployment tool; an inflatable structure wrapped around a sleeve, the inflatable structure being directly attached to the deployment tool or wrapped around the sleeve; a drilling reamer positioned at a short distance above the deployment tool; a packer positioned at a certain distance above the deployment tool; a pump configured to pump a liquid substance capable of solidifying to inflate the inflatable structure and seal off the fracture; a sealing fluid path through the deployment tool for allowing drilling fluid to flow to the drill-bit.

21. A sealing tool of claim 20, wherein the hole enlarging tool is deactivated after enlarging the portion of the wellbore surrounding the fracture.

22. A sealing tool of claim 20, wherein the sealing fluid path through the deployment tool is re-opened after deactivating the packer.