Patent Application
20250034964
Boreholes may be drilled into subterranean formations to recover valuable hydrocarbons, among other functions. Various operations may be performed before, during, and after the borehole has been drilled to produce and continue the flow of the hydrocarbon fluids to the surface.
A typical operation concerning downhole applications may be to apply a seal within a borehole. A seal may isolate and contain produced hydrocarbons and pressures within the borehole. There may be a variety of different tools and equipment used to create seals between the outside of a production tubing string and the inside of a casing string, liner, or the wall of a wellbore. Substantial pressure differentials across a seal may induce failure of the seal and may result in substantial loss of time, money, and equipment, and may even result in harm to individuals. Additionally, expanding a wellbore seal may induce substantial deformation and internal stress on a sealing element, which may increase the chance of failure (e.g., due to breaking or tearing). The design and manufacture of wellbore seals may be limited in structure and material choice in order to minimize the chance of failure. It may be suitable to explore alternative manufacturing processes to produce improved sealing elements.
These drawings illustrate certain aspects of some of the embodiments of the present disclosure and should not be used to limit or define the disclosure.
Disclosed herein are improved sealing elements and, more particularly, sealing elements that have regions with different Young's modulus. By having distinct regions with different Young's modulus, the sealing element may be considered multi-modulus in that the sealing element includes at least two regions with a different Young's modulus. In some embodiments, sealing element has localized fiber loading to provide regions with different Young's modulus.
Young's modulus is a measure of the relationship of an applied stress to the resultant strain. In general, a highly deformable (plastic) material will exhibit a lower modulus when the confined stress is increased. Thus, the Young's modulus is an elastic constant that demonstrates the ability of the tested material to withstand applied loads. Young's modulus as measured using ASTM D412 for elastomers and ASTM D638 for thermoplastics. By including regions with a different Young's modulus in a sealing element, the properties of the sealing element can be optimized to address different challenges.
Sealing elements may generally be elastomeric. While these sealing elements may be able to withstand high pressures, they may be subject to extrusion failure when exposed to high differential pressures. This may result in extrusion of the sealing element along the pressure gradient and the loss of annular seal. In present embodiments, extrusion resistance of a sealing element may be improved by incorporation of a region of higher modulus into the sealing element. For example, the high modulus region may be used at extrusion prone surfaces of the sealing element while other regions of the sealing element are lower modulus. By maintaining regions of lower modulus, the sealing element can maintain flexibility, especially in critical sealing areas, in accordance with some embodiments. Advantageously, the sealing element may have improved extrusion resistance from the higher modulus region while also maintaining desirable sealing properties. The high modulus region may also be incorporated into regions of the sealing element where a high abrasion resistance is required, thus also improving the abrasion resistance of the sealing element.
The sealing element may include at least two regions with a different Young's modulus. To be considered different, the Young's modulus of the regions must vary by about 5% or greater. The sealing element should also maintain significantly large strain capacities, for example, greater than 25% in both regions. Strain capacity is the capability of a material to stretch under pressure and is measured as elongation at break. In some embodiments, the sealing element includes a lower modulus region and a higher modulus region The terms “lower” and “higher” as used with respect to these regions is not intended to imply any specific degree of elasticity but are instead used as terms of degree to degree their relationship to one another. The higher modulus region may be considered a “higher” modulus region because its Young's modulus is higher than the Young's modulus of the lower modulus region.
The lower modulus region may comprise any of a variety of suitable materials for downhole sealing applications. For example, the sealing element may comprise an elastomer. Examples of suitable elastomer include nitrile butadiene (NBR) which is a copolymer of acrylonitrile and butadiene, carboxylated acrylonitrile butadiene (XNBR), hydrogenated acrylonitrile butadiene (HNBR) which is commonly referred to as highly saturated nitrile (HSN), carboxylated hydrogenated acrylonitrile butadiene (XHNBR), hydrogenated carboxylated acrylonitrile butadiene (HXNBR), ethylene propylene (EPR), ethylene propylene diene (EPDM), tetrafluoroethylene and propylene (FEPM), fluorocarbon (FKM), perfluoroelastomer (FEKM), and combinations thereof. Thermoplastics, thermosets, and thermoplastic vulcanizates may also be suitable in some examples. For example, the sealing element may comprise a thermoplastic, such as an epoxy or phenolic. Examples of suitable thermoplastics include polyphenylene sulfide (PPS), polyetheretherketones such as (PEEK), (PEK) and (PEKK), polytetrafluoroethylene (PTFE), and combinations thereof.
The lower modulus region may be included in the sealing element in any suitable amount. For example, the lower modulus region may be included in the sealing element in an amount of about 50% to about 99% by volume of the sealing element. In some embodiments, the sealing element may be included in an amount of about 55% to about 99%, 60% to about 99%, about 70% to about 99%, about 80% to about 99%, about 90% to about 99%, about 50% to about 98%, about 55% to about 98%, about 60% to about 98%, about 70% to about 98%, about 80% to about 98%, about 90% to about 98%, about 50% to about 95%, about 55% to about 95%, about 60% to about 95%, about 70% to about 95%, about 80% to about 95%, or about 90% to about 95% by volume of the sealing element.
The higher modulus region may include a reinforcing agent and a matrix material. The matrix material may include any suitable material, including elastomers, thermoplastics, thermosets and thermoplastic vulcanizates. Examples of suitable elastomer include nitrile butadiene (NBR) which is a copolymer of acrylonitrile and butadiene, carboxylated acrylonitrile butadiene (XNBR), hydrogenated acrylonitrile butadiene (HNBR) which is commonly referred to as highly saturated nitrile (HSN), carboxylated hydrogenated acrylonitrile butadiene (XHNBR), hydrogenated carboxylated acrylonitrile butadiene (HXNBR), ethylene propylene (EPR), ethylene propylene diene (EPDM), tetrafluoroethylene and propylene (FEPM), fluorocarbon (FKM), perfluoroelastomer (FEKM), and combinations thereof. The elastomer included in the matrix material of the higher modulus region may be the same or different than the elastomer of the lower modulus region. In some embodiments, the matrix material may be included in the higher modulus region in an amount of about 60% to about 99% by volume and, alternative, about 65% to about 97% by volume of the higher modulus region. To provide an increased modulus, the higher modulus region may further include a reinforcing agent, such as a powders or fibers. Examples of suitable powers that may be used as the reinforcing agent may include carbon black, fumed silica, treated clay, graphite, and combinations thereof. Where used, the powders can include single walled or multi-walled nano-tubes. Examples of suitable fibers my include glass fibers {e.g., e-glass, A-glass, E-CR-glass, C-glass, D-glass, R-glass, and/or S-glass), cellulosic fibers (e.g., viscose rayon, cotton, etc.), carbon fibers, graphite fibers, metal fibers {e.g., steel, aluminum, etc.), ceramic fibers, metallic-ceramic fibers, aramid fibers, and combinations thereof. Specific examples of suitable fibers include aramids, cotton flock, rayon, polyesters, and polyamides. The reinforcing agent may be included in the higher modulus region in an amount of about 1% to about 40% by volume and, alternatively, about 3% to about 35% by volume of the higher modulus region.
The higher modulus region may be included in the sealing element in any suitable amount. For example, the lower modulus region may be included in the sealing element in an amount of about 1% to about 50% by volume of the sealing element. In some embodiments, the sealing element may be included in an amount of about 1% to about 45%, 1% to about 40%, about 1% to about 30%, about 1% to about 20%, about 1% to about 10%, about 2% to about 50%, about 2% to about 45%, about 2% to about 40%, about 2% to about 30%, about 2% to about 20%, about 2% to about 10%, about 5% to about 50%, about 5% to about 45%, about 5% to about 40%, about 5% to about 30%, about 5% to about 20%, or about 5% to about 10% by volume of the sealing element.
The higher modulus region may have a Young's modulus that is about 5% or greater than the lower modulus region. For example, the higher modulus region may have a Young's modulus that is 5% to about ** % greater than the lower modulus region. In some embodiments, the higher modulus region may have Young's Modus that is 1 time, 2 times, 3 times, 5 times, or even 100 times greater than the lower modulus region. The specific difference may depend, for example, on the composition of each region and the particular reinforcing agent used. For example, a higher modulus region that comprise a thermoplastic with a lower modulus region that comprises an elastomer may have a much larger difference when a system where both regions comprise elastomers.
The sealing elements can be made by any suitable techniques. For example, standard sealing manufacturing techniques may be used for their construction. In some embodiments, the reinforcing agent (e.g., fibers) may be incorporated into the matrix material (e.g., elastomer) either directly or as a masterbatch. For example, the reinforcing agent incorporated into the matrix material through shear mixing method using two roll mill or internal mixers. In some embodiments, A preform to be made from the rubber compound using extrusion, punching or through any similar process. Preform can be made as a single material with lower and higher modulus regions or can be made as two separate preforms and can be joined together in molding. Both the lower and higher modulus region portion should be with similar cure characteristics to ensure proper bonding. Molding of the preform can be done through compression molding or through transfer molding, for example.
The sealing element can be used for a variety of different downhole sealing applications. For example, the sealing element may be an O-ring seal, D-seal, T-seal, V-seal, X-seal, flat seal, lip seal, back-up ring, or a packing element. The sealing element can have a variety of different configurations. For example, the lower modulus region and the higher modulus region can be arranged in the sealing element with respect to one another in a variety of different configurations. In some embodiments, the sealing element may generally be annular in shape. In some embodiments, the higher modulus region forms at least a portion of an outer surface of the sealing element. In some embodiment, the higher modulus region may form a core of the sealing element, for example, to provide a reinforced core. In some embodiments, the higher modulus region may be disposed in one or more corners of the sealing element, for example, to provide reinforced corners. In some embodiments, the higher modulus region may be disposed on one or more ends of the sealing element, for example, to provide reinformed ends. The higher modulus region may be disposed on interfaces (e.g., corners, ends, outer surfaces, etc.) between components, for example, to reinforce these regions that would otherwise have an extrusion gap that would be susceptible to damage. By reinforcing the interfaces with the higher modulus region, the softer systems may be protected from damage.
As illustrated, downhole tools may be run into wellbore 104 on conveyance line 112. Wellbore 114 may extend through the various earth strata including formation 106. A casing 116 may be secured within wellbore 114 by cement (not shown). Casing 116 may be made from any material such as metals, plastics, composites, or the like, may be expanded or unexpanded as part of an installation procedure. Additionally, it is not necessary for casing 116 to be cemented into wellbore 114. In examples, production tubing 118 may be secured within casing 116. Production tubing 118 may be any suitable tubing string utilized in the production of hydrocarbons. In examples, production tubing may be permanently disposed within casing 116 by cement (not shown). Packer 102 may be disposed on or near production tubing 118.
Without limitation, any suitable type of packing element 102 may be used. In general, a packing elements may be device that can be run into a wellbore with a smaller initial outside diameter that then expands externally to seal the wellbore. The packing element 102 may employ flexible, elastomeric elements that expand. The packing element 102 may be a production packer, test packer, isolation packer, etc. A production packer may isolate the annulus (e.g., between the production tubing and the wellbore wall) and anchor or secure the bottom of the production tubing string. The packing element 102 incorporates a means of securing the packer against the casing or liner wall, such as a slip arrangement, and a means (e.g., sealing elements) of creating a reliable hydraulic seal to isolate the annulus, typically by means of an expandable elastomeric element. Packers, such as packing element 102, are typically classified by application, setting method and possible retrievability. Suitable types of packers may include whether they are permanently set or retrievable, mechanically set, hydraulically set, and/or combinations thereof.
While not separately shown, packing element 102 comprises a lower modulus region and a higher modulus region, as described in more detail herein. Packing element 102 may be set downhole to seal off a portion of wellbore 114. When set, packing element 102 may isolate zones of the annulus between wellbore 114 and a tubing string by providing a seal between production tubing 118 and casing 116. In examples, packing element 102 may be disposed on production tubing 118. The downhole tools may be disposed around conveyance line 112 and run into wellbore 114 when desired to actuate packer 102. Downhole tools may temporarily couple to packer 102 to initiate a sealing operation within wellbore 114.
It should be understood by those skilled in the art that present examples are equally well suited for use in wellbores having other directional configurations including vertical wellbore, horizontal wellbores, deviated wellbores, multilateral wells and the like. Accordingly, it should be understood by those skilled in the art that the use of directional terms such as above, below, upper, lower, upward, downward, uphole, downhole and the like are used in relation to the illustrative embodiments as they are depicted in the figures, the upward direction being toward the top of the corresponding figure and the downward direction being toward the bottom of the corresponding figure, the uphole direction being toward the surface of the well and the downhole direction being toward the toe of the well. Also, even though
Accordingly, the present disclosure may provide sealing elements that comprise a region of localized fiber loading. The methods and systems may include any of the various features disclosed herein, including one or more of the following statements.
To facilitate a better understanding of the present invention, the following examples of certain aspects of some embodiments are given. In no way should the following examples be read to limit, or define, the entire scope of the disclosure.
Testing was performed to evaluate failure performance for a sealing element in accordance with one or embodiments. The sealing element tested was an O-ring as shown on
To evaluate failure performance, testing was carried out under hydraulic differential pressure. Test specimens were prepared according to
The results of the testing are shown on
For the sake of brevity, only certain ranges are explicitly disclosed herein. However, ranges from any lower limit may be combined with any upper limit to recite a range not explicitly recited, as well as, ranges from any lower limit may be combined with any other lower limit to recite a range not explicitly recited, in the same way, ranges from any upper limit may be combined with any other upper limit to recite a range not explicitly recited. Additionally, whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range are specifically disclosed. In particular, every range of values (of the form, “from about a to about b,” or, equivalently, “from approximately a to b,” or, equivalently, “from approximately a-b”) disclosed herein is to be understood to set forth every number and range encompassed within the broader range of values even if not explicitly recited. Thus, every point or individual value may serve as its own lower or upper limit combined with any other point or individual value or any other lower or upper limit, to recite a range not explicitly recited.
Therefore, the present embodiments are well adapted to attain the ends and advantages mentioned as well as those that are inherent therein. The particular embodiments disclosed above are illustrative only, as the present embodiments may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Although individual embodiments are discussed, all combinations of each embodiment are contemplated and covered by the disclosure. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. Also, the terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee. It is therefore evident that the particular illustrative embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the present disclosure.
