Patent Publication Number: US-10323476-B2

Title: Internally trussed high-expansion support for inflow control device sealing applications

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application is a U.S. National Stage Application of International Application No. PCT/US2014/065218 filed Nov. 12, 2014, which is incorporated herein by reference in its entirety for all purposes. 
     TECHNICAL FIELD 
     The present disclosure relates to wellbore completion operations and, more particularly, to a downhole completion assembly for sealing an inflow control device installed along a length of production tubing. 
     BACKGROUND 
     The advent of horizontal drilling has been considered a significant advance in the oil and gas industry. While this form of drilling has increased the complexity and cost of drilling, it has also increased economic returns to well operators. Horizontal drilling has lead to increased production because it maximizes the reservoir contact. This is because most oil and gas fields are generally horizontally situated. It has also enabled tapping reserves from zones previously thought too difficult to reach, such as thin oil zones. 
     Although horizontal completion technology and techniques have improved over the years, horizontal wells continue to face challenges. One of those challenges relates to uneven influx of reservoir fluid to the wellbore. This causes early water and gas breakthrough. Water and gas coning in the heel of the well is often blamed for these challenges. Another reason for water and gas breakthrough is related to uneven permeability and fractures or differences in fluid mobility, which occurs in wells with high-viscosity oil. Since it becomes easier for the reservoir fluid to be produced through one section compared to the other, having an even drawdown under conditions of uneven permeability or uneven fluid mobility can lead to premature breakthrough of water or gas. 
     In reservoirs which are largely homogenous with higher drawdown in the heel, one solution to the challenge of water and gas breakthrough is to balance the drawdown from the heel to the toe. This can be done by applying a controlled pressure drop from the annulus to the production tubing in the heel using inflow control devices (ICDs). The use of these devices reduces the drawdown and the fluid rate from this particular section. In reservoirs which are mostly heterogenous, where the drawdown is more equally distributed along the wellbore, the drawdown is reduced in high-permeability sections to allow low-productivity sections to flow more oil. This is typically achieved through equal distribution of the ICDs. ICDs have thus been very effective at delaying potential water or gas breakthroughs and thus allowing more oil to be produced throughout the life of the well. 
     There are some instances, however, where the balancing achieved using ICDs is insufficient to delay water and gas coning at the heel of a well. In those instances, it is desirable to close these zones at the heel while still allowing production from the deeper zones. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the present disclosure and its features and advantages, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  illustrates a downhole completion system used to seal an inflow control device (ICD) completion, according to one or more embodiments; 
         FIGS. 2A and 2B  illustrate contracted and expanded sections of a truss structure, respectively, according to one or more embodiments; 
         FIGS. 3A and 3B  illustrate a truss structure disposed on an expansion tool in contracted and expanded configurations, respectively, according to one or more embodiments; and 
         FIG. 4  illustrates a sealing structure layered on a truss structure, with an expansion tool inserted inside of the truss structure with the truss and sealing structures in retracted configurations, according to one or more embodiments; 
         FIG. 5  is a cross-sectional view of truss and sealing structures in expanded configurations showing the sealing structure in engagement with an ICD completion; and 
         FIG. 6  is a cross-sectional view of truss and sealing structures in expanded configurations showing the downhole completion system in engagement with an ICD completion. 
     
    
    
     DETAILED DESCRIPTION 
     Illustrative embodiments of the present disclosure are described in detail herein. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation specific decisions must be made to achieve developers&#39; specific goals, such as compliance with system related and business related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of the present disclosure. Furthermore, in no way should the following examples be read to limit, or define, the scope of the invention. 
     The present disclosure provides a downhole completion system that features an expandable sealing structure and corresponding internal truss structure that are capable of being run through existing production tubing and subsequently expanded to support and seal the internal surface of an ICD so as to restrict the flow of fluids from the wellbore into the production tubing in the region where the ICD is installed. Once the sealing structure is run to its proper downhole location, which in most cases will be between the heel and toe of a horizontal section, it may be expanded by any number of expansion tools that are also small enough to axially traverse the production tubing. In operation, the expanded sealing structure may be useful in sealing the ICD thereby restricting the influx of unwanted fluids into the production tubing. The internal truss structure may be arranged within the sealing structure and useful in radially supporting the expanded sealing structure. In some embodiments, the sealing structure and corresponding internal truss structure are expanded at the same time with the same expansion tool. 
     The downhole completion system may provide advantages in that it is small enough to be able to be run-in through existing production tubing. When expanded, the disclosed downhole completion system may provide sufficient expansion within an ICD to adequately restrict the influx of undesired formation fluids, such as water and gas. As a result, the life of a well may be extended, thereby increasing profits and reducing expenditures associated with the well. As will be appreciated by those of ordinary skill in the art, the methods and systems disclosed herein may salvage or otherwise revive certain types of wells, which were previously thought be economically unviable. 
     Referring to  FIG. 1 , illustrated is an exemplary downhole completion system  100 , according to one or more embodiments disclosed. As illustrated, the system  100  may be configured to be downstream from the heel portion  102  of horizontal wellbore  104  to seal an inflow control device (ICD)  106  installed along the tubing string  108 . In other embodiments, an ICD may be installed along casing. As used herein, the term “casing” is intended to be understood broadly so as to casing and/or liners. Furthermore, as used, herein, the term or phrase “downhole completion system” should not be interpreted to refer solely to wellbore completion systems as classically defined or otherwise generally known in the art. Rather, the downhole completion system may also refer to, or be characterized as, a downhole fluid transport system. 
     While  FIG. 1  depicts the system  100  as being arranged adjacent to the heel portion  102  of a horizontally-oriented wellbore  104 , it will be appreciated that the system  100  may be equally arranged in a vertical or slanted portion of the wellbore  104 , or any other angular configuration therebetween, without departing from the scope of the disclosure. Additionally, the system  100  may be arranged along other portions of the horizontal wellbore  104  in order to seal ICDs  106  located closer to the toe portion  109  of the horizontal wellbore  104 . 
     In present embodiments, the system  100  includes a truss structure and a sealing structure disposed around the truss structure. The system  100  may be run in through the tubing string  108 , past the heel portion  102  and is brought into alignment with the ICD  106  adjacent to the heel portion  102 . From this position, as described in detail below, an expansion tool may be actuated to expand the truss structure and the sealing structure of the system  100  against an inner portion of the ICD  106 , thereby sealing the ICD  106 . 
     Having generally described the context in which the disclosed downhole completion system  100  may be utilized, a more detailed description of the components that make up the system  100  will be provided. To that end,  FIGS. 2A and 2B  illustrate the truss structure  110  of the system  100 . In one embodiment, the truss structure  110  is formed of a stainless steel tube, which has a pattern cut into it that enables it to expand in diameter more than 50% and up to approximately 300% without changing axial length, while at the same time maintaining a useful strength. It should be noted that any suitable expansion range is contemplated for the expanded diameter of the tube without changing its axial length. The tube serves as the support structure upon which a separate sealing layer is added. In some embodiments, a feature of the pattern is that it enables the tube to expand radially into a trussed shape that is internal to the outer sealing layer. The term “trussed shape” refers to the expanded pattern of the tube having open spaces outlined by interconnected portions of the tube (e.g., trusses). These trusses may provide additional strength and sealing capabilities. The sealing element/tube assembly may be expanded in a number of different ways (e.g., a cone, downhole power unit, etc.), but one embodiment is expansion via a hydraulic inflation tool  112 , such as an inflatable packer, which is shown generally in  FIGS. 3A and 3B .  FIG. 3A  illustrates the truss structure  110  in its collapsed/contracted configuration disposed on a hydraulic inflation tool  112 .  FIG. 3B  illustrates the truss structure  110  in its expanded configuration upon activation of the hydraulic inflation tool  112 . In one embodiment, the truss structure  110  is formed of a sheet metal having memory characteristics. 
     In certain embodiments, the truss structure  110  is formed by cutting the desired pattern into a 2.5 to 3 inch diameter, 30 inch long, schedule 40/80 stainless steel pipe. As those of ordinary skill in the art will appreciate, the size and composition of the truss structure  110  is not limited to this exemplary embodiment. Further, it will be appreciated that the truss structure  110  may be formed using any suitable manufacturing technique including, but not limited to, casting, 3D printing, etc. In the illustrated embodiment, the cut pattern is formed of a plurality of rows  114  of perforations disposed equidistant around the circumference of the truss structure  110 . These perforations may form a plurality of expandable cells  122  defined on the truss structure  110 . Each row  114  is formed of a plurality of generally opposing, longitudinally offset arc-shaped perforations  116 , each having a dimple  118  formed in the approximate mid-section of the arc, as shown in  FIG. 2A . The arc-shaped perforations  116  are arranged along the length of the truss structure  110  and have holes  120  formed at the beginning and end of each arc. The holes  120  and the arcs  116  may completely penetrate the steel structure of pipe. In other embodiments, the arcs  116  themselves may only partially penetrate through the pipe wall. In still further embodiments, neither the arcs  116  nor the holes  120  may penetrate through the pipe wall. The pattern is preferably cut using a water jet, but may also be cut using a laser. 
     Each of the expandable cells  122  includes a perimeter that is defined by the arc-shaped perforations  116 , the dimples  118 , and the holes  120 . Upon expansion of the cells  122 , the arc-shaped perforations open up and form opposing offset generally pie-shaped openings in the body of the truss structure  110 , which are formed along the length of the pipe, as shown in  FIG. 2B . It should be apparent that other embodiments may be utilized, such as where the truss structure  110  uses linear rather than arc-shaped perforations  116 . In other embodiments, the perforations  116  are not generally opposing. 
     It should be noted that any suitable shaped perforations  116  that permit the truss structure  110  to expand may be used in other embodiments. In addition, any suitable number of such perforations  116  may be utilized to provide the desired expansion. Furthermore, any suitable relationship between the perforations  116  may be contemplated in the disclosed embodiments. Still further, the openings  122  in the body of the truss structure  110  may have any suitable shaped upon expansion of the truss structure  110 . 
     The run-in configuration of the downhole completion system  100  is shown in  FIG. 4 , with a sealing structure  130  disposed on the truss structure  110 . The sealing structure  130  is an elongate tubular member. In some embodiments, the sealing structure  130  may be formed by coiling a sealable material around the truss structure  110 . The sealing material may be formed of rubber; thermoset plastics; thermoplastics; fiber-reinforced composites; cementious compositions; corrugated, crenulated, circular, looped or spiral metal or metal alloy; any combinations of the forgoing; or any other suitable sealing material. As illustrated, the truss structure  110  may be nested inside the sealing structure  130  when the sealing structure  130  is in its contracted configuration. In some embodiments, multiple truss structures  110  may be nested to create a longer length. 
     In some embodiments, the sealing structure  130  may further include a sealing element  132  disposed about at least a portion of the outer circumferential surface of the sealing structure, as illustrated in  FIG. 5 . In some embodiments, an additional layer of protective material  134  may surround the outer surface of the sealing element  132  to protect the sealing element  132  as it is advanced through the wellbore. The protective material  134  may further provide external support to the sealing structure  130 . For example, the protective material  134  may provide external support to the sealing structure  130  (and truss structure) by holding the sealing structure  130  under a maximum running diameter prior to the placement and expansion of the truss structure within the tubing string  108 . The term “maximum running diameter” refers to a diameter that the sealing structure  130  is not exceed while the downhole completion system  100  is being run through tubing in the wellbore. Indeed, the protective material  134  may exert a slight compressive force on the sealing structure  130  (and the truss structure) to maintain these structures in a compressed position while the system is lowered through the wellbore. After reaching the appropriate position in the wellbore, an inflation tool, as described above, may exert a force on the inside surface of the truss structure that opposes and overcomes the compressive force from the protective material  134  in order to expand the completion system  100 . 
     In operation, the sealing element  132  may be configured to expand as the sealing structure  130  expands and ultimately engage and seal against the inner diameter of the ICD  106 . In some embodiments, the sealing element  132  may be arranged at two or more discrete locations along the length of the sealing structure  130 . In some embodiments, the sealing element  132  may be arranged at a location along the length of the sealing structure  130  that corresponds with the location of apertures in the ICD  106 , through which production fluids would otherwise enter the tubing string  108 . The sealing element  132  may be made of an elastomer, a rubber, or any other suitable material. The sealing element  132  may further be formed from a swellable or non-swellable material. In at least one embodiment, the sealing element  132  may be a swellable elastomer that swells in the presence of at least one of water and oil. However, it will be appreciated that any suitable swellable material may be employed and remain within the scope of the present disclosure. 
     In other embodiments, the material for the sealing elements  132  may vary along the sealing section in order to create the best sealing available for the fluid type that the particular seal element may be exposed to. For instance, one or more bands of sealing materials may be located as desired along the length of the sealing section. The material used for the sealing element  132  may include swellable elastomeric, as described above, and/or bands of viscous fluid. The viscous fluid, for instance, may be an uncured elastomeric that will cure in the presence of well fluids. The viscous fluid may include a silicone that cures with water in some embodiments. In other embodiments, the viscous fluid may include other materials that are a combination of properties, such as a viscous slurry of the silicone and small beads of ceramic or cured elastomeric material. The viscous material may be configured to better conform to the annular space between the expanded sealing structure and the varying shape of the tubing string  108  and/or the ICD  106 . It should be noted that to establish a seal, the material of the sealing element  132  does not need to change properties, but only have sufficient viscosity and length to remain in place the life of the well. The presence of other fillers, such as fibers, may enhance the viscous material. 
     As illustrated, and as will be discussed in greater detail below, at least one truss structure  110  may be generally arranged within a corresponding sealing structure  130  and may be configured to radially expand to seal a portion of production tubing. For example,  FIG. 6  illustrates a cross-section of an ICD completion (as described above with reference to  FIG. 1 ) being sealed by the downhole completion system  100  described above. As illustrated, the ICD  106  includes various ports  150  through which production fluid would normally flow from the subterranean formation into the tubing string  108  with a calibrated pressure drop. In the downhole completion system  100 , the expanded truss structure  110  holds the sealing structure  130  against these apertures  150 , thereby sealing the ICD  106  so that water or gas does not flow into the tubing string  108 . As illustrated, there is no expansion tool present within the system  100 , since the expansion tool may function as a deployment device that is removable after being used to expand the system  100  into sealing engagement with the ICD  106 . 
     During installation, the system  100  may be combined with a mechanical connection to the surface for translating the system  100  through the tubing string  108 . The mechanical connection may include a conveyance device used to transport the sealing structure  130  and truss structure  110  in their respective contracted configurations through the tubing string  108  to the ICD  106 . The conveyance device may include a wireline, a slickline, coiled tubing or jointed tubing. In some embodiments, the system  100  may be run in to the ICD  106  in a contracted state on an expansion tool coupled to the mechanical connection prior to expansion via the expansion tool. After expansion of the system  100 , the expansion tool may be released and translated out of the tubing string  108  via the mechanical connection. In some embodiments, the system  100  may be positioned within the ICD  106  to seal the ports  150  through the use of a spinner, a casing-collar locator, tagging off of a known restriction (e.g., landing nipple), or any other method. In some embodiments, the system  100  and/or the ICD  106  may be equipped with a sensor for determining the position of the system  100  with respect to the ICD  106  and the ports  150  that need to be covered. 
     In some embodiments, multiple different ICDs  106  located along the horizontal wellbore  104  may need to be sealed throughout the life of the well. For example, the ICD  106  located adjacent to the heel portion  102  of the horizontal wellbore  104  may be sealed first and then another ICD  106  located closer to the toe of the horizontal wellbore  104  may need to be sealed to prevent water encroachment. In such situations, an additional downhole completion system  100  may be deployed into the horizontal wellbore  104  to seal the other ICD  106 . As illustrated, the additional system  100  may be translated (in a contracted configuration) through the expanded system  100  that is already sealing the ICD  106  near the heel portion  102 . This is because an inner diameter of the truss structure  110  in the expanded configuration is greater than an outer diameter of the downhole completion system  100  in the contracted configuration. Thus, sealing can be provided along the ICDs  106  from heel to toe within the horizontal wellbore  104 . 
     The disclosed downhole completion system  100  may be deployed directly into the tubing string  108  to seal ICDs  106  at any point along the length of the horizontal wellbore  104  and at any point during production. This allows flexibility in sealing off various ICDs  106  in order to increase the amount of formation fluids produced through the horizontal wellbore  104 . An operator does not have to anticipate which zones of the horizontal wellbore  104  might start taking in water or gas during the lifetime of the well. In addition, the use of the system  100  to seal the ICD  106  near the heel portion  102  of the wellbore does not prevent the installation of another system  100  further along the horizontal wellbore  104 . 
     Embodiments disclosed herein include: 
     A. A method of sealing an inflow control device installed in a subterranean formation which is producing an undesirable fluid that includes conveying a truss structure and sealing structure disposed thereon into production tubing adjacent the inflow control device. The truss and sealing structures being radially expandable between a contracted configuration and an expanded configuration. The method also includes radially expanding the truss and sealing structures from their contracted configurations to an expanded configuration whereby the sealing structure seals against the inflow control device thereby creating a flow restriction between the subterranean formation and an inside surface of the production tubing. 
     B. A downhole completion system includes a truss structure and a sealing structure disposed about the truss structure. The truss structure is radially expandable between a contracted configuration and an expanded configuration. The sealing structure is radially expandable between a contracted configuration and an expanded configuration. The sealing structure is operable to seal one or more apertures in an inflow control device so as to restrict the flow of fluids through the apertures. 
     Each of the embodiments A and B may have one or more of the following additional elements in combination: Element 1: wherein when in the expanded configuration the truss structure radially supports the sealing structure. Element 2: further including conveying the sealing and truss structures into the production tubing simultaneously, the truss structure being nested inside the sealing structure when the sealing structure is in its contracted configuration. Element 3: wherein radially expanding the truss structure into its expanded configuration further comprises expanding a plurality of expandable cells defined on the truss structure. Element 4: wherein the axial length of the truss structure in the contracted and expanded configurations is substantially the same. Element 5: wherein a diameter of the truss structure is expanded by more than 50% when the truss structure is expanded from the contracted configuration to the expanded configuration. Element 6: further including conveying the truss structure and the sealing structure into the production tubing until the truss structure and the sealing structure are disposed in proximity to the inflow control device based on sensor feedback, and radially expanding the truss and sealing structures from their contracted configurations to the expanded configuration when the truss and sealing structures are disposed in proximity to the inflow control device. Element 7: further including conveying a second truss structure with a second sealing structure disposed thereon in a contracted configuration into the production tubing and through the expanded truss structure. 
     Element 8: further including a conveyance device to transport the sealing and truss structures in their respective contracted configurations through the production tubing to the inflow control device. Element 9: wherein the conveyance device is selected from the group consisting of wireline, slickline, coiled tubing and jointed tubing. Element 10: further including a deployment device to radially expand the sealing and truss structures from their respective contracted configurations to their respective expanded configurations, the truss structure being expanded while arranged at least partially within the sealing structure. Element 11: wherein the deployment device is selected from the group consisting of a hydraulic inflation tool and an inflatable packer. Element 12: wherein when in the expanded configuration the truss structure radially supports the sealing structure. Element 13: wherein the truss structure includes a plurality of expandable cells. Element 14: wherein at least one of the plurality of expandable cells includes an arc-shaped perforation with holes formed at the beginning and end of the arc-shaped perforation. Element 15: wherein the truss structure has a diameter which expands by more than 50% when the truss structure is expanded from the contracted configuration to the expanded configuration. Element 16: wherein the axial length of the truss structure in the contracted and expanded configurations is substantially the same. Element 17: wherein an inner diameter of the truss structure in the expanded position is greater than an outer diameter of the sealing structure in the contracted position. Element 18: wherein a swellable material is disposed about at least a portion of the truss structure. 
     Although the present disclosure and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the disclosure as defined by the following claims.