Not applicable.
Not applicable.
Conventional hydraulic fracturing operations (for drilled wells, such as oil and gas wells) typically use drillable zonal isolation devices (such as composite frac plugs) as the preferred method for treating and completing multi-zone horizontal wells. In application, such frac plugs would be located and set within the completion liner (e.g. cased well) one at a time. After placement of each frac plug, high pressure fracturing would be carried out in the reservoir upstream of the plug. Once all fracturing operations have been completed for the well, the plugs would then be drilled out to open the completion liner to production.
These conventional fracturing operations can be quite time consuming and costly, however. Additionally, there is the risk that it might not be possible to drill out the frac plugs located furthest in the toe of the horizontal well (e.g. furthest into the well and away from the head of the well), for example due to pipe lockup. In such instances, the operator would lose production for the intervals of the well not drilled out (resulting in a less efficient or productive well). The presently disclosed embodiments may solve one or more of these problems by providing an improved plugging technique, which may not require drill out in order to open the completion liner to full production. The presently disclosed embodiments may also provide for improved plug seat setting. Persons of ordinary skill in the art field will appreciate these and other possible benefits.
For a more complete understanding of the present disclosure, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description, wherein like reference numerals represent like parts.
It should be understood at the outset that although illustrative implementations of one or more embodiments are illustrated below, the disclosed systems and methods may be implemented using any number of techniques, whether currently known or not yet in existence. The disclosure should in no way be limited to the illustrative implementations, drawings, and techniques illustrated below, but may be modified within the scope of the appended claims along with their full scope of equivalents.
The following brief definition of terms shall apply throughout the application:
The term “up”, “uphole”, “above”, or the like, when used in reference to well or the tool string for example, shall mean towards the surface or towards the top or away from the end/toe of the well; similarly, the term “down”, “downhole”, “below”, or the like shall mean away from the surface or towards the bottom or end/toe of the well;
The term “ring” shall, when used in reference to an element for use within a well or tool string for example, typically mean that the element has a hole, opening, or longitudinal bore therethrough (for example, of the sort which might allow fluid flow through the element), and typically such bore would be located approximately along the central (longitudinal) axis of the element;
The term “comprising” means including but not limited to, and should be interpreted in the manner it is typically used in the patent context;
The phrases “in one embodiment,” “according to one embodiment,” and the like generally mean that the particular feature, structure, or characteristic following the phrase may be included in at least one embodiment of the present invention, and may be included in more than one embodiment of the present invention (importantly, such phrases do not necessarily refer to the same embodiment);
If the specification describes something as “exemplary” or an “example,” it should be understood that refers to a non-exclusive example;
The terms “about” or approximately” or the like, when used with a number, may mean that specific number, or alternatively, a range in proximity to the specific number, as understood by persons of skill in the art field (for example, +/−10%); and
If the specification states a component or feature “may,” “can,” “could,” “should,” “would,” “preferably,” “possibly,” “typically,” “optionally,” “for example,” “often,” or “might” (or other such language) be included or have a characteristic, that particular component or feature is not required to be included or to have the characteristic. Such component or feature may be optionally included in some embodiments, or it may be excluded.
Embodiments may relate generally to methods and devices for setting a plug seat within a downhole well, for example in advance of fracing operations. The disclosed expandable plug seat embodiments typically include an expandable slip ring (which in some embodiments may optionally have an elastomeric seal on its exterior) and one or more wedge rings (and in some embodiments, the plug seat may consist essentially of or consist only of a slip ring and one or more wedge rings). For example, typical embodiments might include dual wedge rings, with an upper wedge ring located above the slip ring and a lower wedge ring located below the slip ring. In other embodiments, a single wedge ring might be located with respect to (for example, above) the slip ring. To set the expandable plug seat in place within the casing of the wellbore, longitudinal force would typically be applied to each of the one or more wedge rings, thereby deforming the expandable slip ring and driving it radially outward and into contact with the casing in the wellbore (due to the interaction of the wedge-like shape of the one or more wedge rings with the inner (radial) surface of the slip ring). In some embodiments, deformation of the slip ring may be plastic and/or elastic (and most typically there would be plastic deformation of the slip ring). In some embodiments, the expandable plug seat may be used with a dissolvable ball (which might be either dissolvable metal or dissolvable polymer), which can be pumped to seat onto the plug seat device (for example, directly on the upper wedge ring). Once the downstream section of the well has been isolated in this manner, hydraulic fracturing operations can commence. Eventually, the ball may dissolve, allowing access to the wellbore without the need to drill the plug. And in some embodiments, one or more element of the plug seat may also dissolve, providing additional radial space in the well (for example, for future production).
So for example, in an embodiment, the plug seat device might comprise an expandable (for example, solid) slip ring (which optionally may have an external elastomeric seal), wherein the expandable slip ring is operable to expand by deforming (plastically and/or elastically) radially outward (upon application of sufficient force on its inner diameter); and one or more wedge rings (for example, operable to slide longitudinally and) located with respect to the slip ring so that application of sufficient longitudinal force on the wedge rings operates to drive the slip ring radially outward (e.g. causing the deformation of the slip ring). Typically, each wedge ring would comprise a wedge-like shape (for example, with the outer diameter of the wedge ring at one end (typically the end farther away from the slip ring in the unset configuration) being larger than the outer diameter of the wedge ring at the opposite end (typically the end closer to the slip ring in the unset configuration)) having an angled vertex/outer surface ranging from about 5-10 degrees (or alternatively 3-20 degrees), for example. And, the slip ring typically would be operable to deform (plastically and/or elastically) radially outward upon application of force from the wedge rings (for example, when sufficient longitudinal force is applied to the one or more wedge rings, driving the one or more wedge rings further into the slip ring, and thereby driving the slip ring radially outward due to the wedge-shape of the wedge rings). Furthermore, the expandable plug seat typically would have an (initial) unset configuration and a set configuration (e.g. after application of sufficient longitudinal force on the wedge rings has driven the slip ring radially outward into contact with the inner surface of the casing and/or wellbore, or until the slip ring has been driven outward so that is outer diameter is approximately equal to the inner diameter of the cased wellbore in question). In the unset configuration, the slip ring typically has an initial outer diameter that is less than the inner diameter of the casing and/or wellbore (for example, allowing the plug seat device to be run downhole); one wedge ring (e.g. the upper wedge ring) is typically located above the slip ring; and optionally one wedge ring (e.g. the lower wedge ring) may be located below the slip ring, for example with (only) the vertex of each wedge ring initially being located within (e.g. radially inward of and contacting the inner diameter/surface of) the slip ring (such that the remainder of the wedge rings typically would be located outside the slip ring and would not contact the slip ring in the unset configuration). So, the plug seat would be transitioned from its unset configuration to its set configuration by application of sufficient longitudinal force on the one or more wedge rings (for example, sliding the wedge rings longitudinally towards each other and/or inward of the slip ring—for example, with more of the wedge ring(s) located within the slip ring). In the set configuration, the one or more wedge rings would have been driven (and are located) further within the slip ring (for example, with the upper wedge ring being driven downward into the slip ring and the lower wedge ring being driven upward into the slip ring), thereby driving the slip ring radially outward via deformation (plastic and/or elastic) of the slip ring until the outer diameter of the slip ring contacts the inner diameter of the casing and/or wellbore with sufficient force to hold the slip ring in place during fracing operations (e.g. the outer diameter of the slip ring in the set configuration is approximately equal to and contacts the inner diameter of the casing and/or wellbore). In other words, the slip ring may be set (e.g. moved from the unset configuration to the set configuration) by application of sufficient longitudinal force on the one or more wedge rings, driving the one or more wedge rings longitudinally further within the slip ring. Thus, the slip ring is configured so that it is operable to transition from its unset position/shape/size (with an outer diameter less than the inner diameter of the cased wellbore, for example) to its set position/shape/size (with outer diameter equal to the inner diameter of the cased wellbore, for example).
The slip ring may optionally have a plurality of anchoring teeth on its outer surface, configured to more securely attach the slip ring in place on the inner surface of the cased wellbore (in the set configuration), for example with the teeth operable/configured to penetrate the casing slightly upon setting of the plug seat (for example, penetrating about 0.010-0.030 inches). The slip ring may optionally also have a plurality of longitudinal slots (which typically might not penetrate all the way through the slip ring, but merely would be indentations forming a thinner wall cross-section at locations in the slip ring—although in other embodiments, the slots could form openings in the slip ring) which may be located radially around the circumference of (e.g. the outer surface) of the slip ring. For example, each such longitudinal slot might have a width of about 0.25 inches, a length of about 2.17 inches, and a depth to not fully penetrate the slip ring, but rather to leave a thin web (for example about 0.030 inches thick). An exemplary embodiment might have about 15 such slots spaced evenly around the exterior circumference of the slip ring. And while some embodiments of the slip ring may have an elastomeric (or other) seal element located on its outer/exterior surface, in other embodiments the slip ring may be configured to effectively form a seal when driven into contact with the cased wellbore (e.g. an effective seal might be formed without the use of any such separate seal element).
Typically, the plug seat device does not contain any additional retention elements (such as a body lock ring or mandrel) beyond the slip ring and/or wedge rings (so for example, the plug seat may consist essentially of or consist of only the slip ring and one or more wedge rings). Additionally, typically the plug seat device would not contain a separate ball seat (e.g., the ball could be landed directly on the upper wedge ring). So for example, the plug seat of some embodiments might consist essentially of (or consist of) only the slip ring and one or more wedge rings. In some embodiments, the slip ring may comprise an outer surface, which may comprise a plurality of anchoring teeth/barbs/ridges in some embodiments for securing/attaching/anchoring the slip ring in place on the inner surface of the casing and/or wellbore (providing a better lock/grip than friction alone). Additionally, the optional elastomeric seal (typically located on the outer/exterior surface of the slip ring in embodiments having such a seal) typically would be configured/operable to effectively seal fluid flow about the exterior of the plug seat device when set in place within the casing (although in other embodiments, such an effective seal might be formed by contact of the slip ring body itself against the cased wellbore, without any need for a separate seal element). Typically, the optional seal diameter would be slightly larger than the outer diameter of the slip ring (for example, larger than the slip teeth diameter) to allow for compression when set. Such a seal might be rated for 10,000 psi differential pressure at 350 degrees Fahrenheit. Exemplary seal materials might be either Nitrile or Aflas.
Often, the plug seat device might be operable or configured to work in conjunction with a sealing ball/plug. Such a ball might be formed of a dissolvable material (which might be metallic or polymeric material operable to dissolve over time (for example, approximately 1-5 days) under exposure to elevated temperature (for example a range of approximately 150-250 degrees Fahrenheit) and either brine (for example KCL brine) or acid (for example approximately 2-5 pH range)). One example of such a dissolvable material might be TervAlloy or similar materials sold by Terves, Inc. Another example of such dissolvable material might be polymer from Bubbletight LLC. In some such embodiments, the slip ring and/or one or more wedge rings in the set configuration might be configured to have an inner diameter sufficiently large to allow for access to the wellbore via tubing or wireline (such that they do not need to be drilled out to allow for production of the well). In some other embodiments, the one or more wedge rings and/or the slip ring of the plug seat might also be formed of such dissolvable material (e.g. material operable to dissolve over time (for example, approximately 1-5 days) under exposure to elevated temperature (for example a range of approximately 150-250 degrees Fahrenheit) and either brine (for example KCL brine) or acid (for example approximately 2-5 pH range)). For example, the one or more wedge rings and/or slip ring might be formed of the same dissolvable material as the sealing ball/plug. This would allow the plugged wellbore to open (after the timeframe needed for fracing, for example) without the need for drilling. And in some embodiments, the plug seat device may be configured/operable to be made-up into a tool string with a wireline-conveyed power charge setting tool (e.g. a wireline pressure setting assembly) and/or a perforating gun assembly. Such a tool string may allow the plug seat to be set and the wellbore to be perforated in one wireline trip downhole (e.g. prior to fracturing the zone).
In the embodiment of
In some embodiments, the plug seat 10 (for example as shown in
The slip ring 520 in this unset configuration has an outer diameter which is configured to be less than the inner diameter of the cased wellbore (for which the plug seat is intended to be used), and is operable/configured to deform (plastically and/or elastically) under application of force from the wedge rings 530, 540 (in order to shift outward from the unset to the set configuration/position). The wedge rings 530, 540 also have a maximum outer diameter which is less than the inner diameter of the cased wellbore (although typically the difference between the maximum outer diameter of the wedge rings 530, 540 and the inner diameter of the cased wellbore is less than or equal to the thickness of the slip ring, for example after deformation to the set position). In
As discussed above, the slip ring 520 is typically made of a material operable to deform from unset to set configuration upon application of sufficient force (radially) via the wedge rings 530, 540. And typically, the wedge rings 530, 540 and/or the slip ring 520 may be formed of dissolvable material (as discussed above). On the other hand, if the wedge rings and/or slip ring are not dissolvable (for example, if only a dissolvable ball is used to close the bore), then they (e.g. one or both) may instead have a bore (e.g. an inner diameter) which is sufficiently large in the set position/configuration to allow for access to the wellbore (below the set plug seat) via tubing or wireline, such that they do not need to be drilled out to allow for downhole work/production below the set plug seat in the wellbore. And as discussed above, the wedge rings 530, 540 typically have a wedge-like shape (for example, in cross-section), with the outer surface having an angle (for example, with respect to a line parallel to the longitudinal bore centerline) ranging from about 3-20 degrees (or for example, alternately 5-20, 5-10, or 10-20 degrees). And as discussed above, the seat plug of
Upon application of sufficient longitudinal force on the wedge rings 530, 540 (for example, with the setting tool pressing down on the upper wedge ring 530 directly, while the lower wedge ring 540 is pressed up against by an insert 508 which interacts with the setting tool in the tool string to transmit upward longitudinal force to the lower wedge ring), the wedge rings 530, 540 move (e.g. slide longitudinally) further into the slip ring (for example, towards each other), with their wedge-like shape driving the slip ring 520 to deform (plastically and/or elastically) outward to the set configuration/position as shown in
Similar to the discussion above regarding
As discussed above, the slip ring 620 is typically made of a material operable to deform from unset to set configuration upon application of sufficient force (radially) via the wedge ring 630. And typically, the wedge ring 630 and/or the slip ring 620 may be formed of dissolvable material (as discussed above). On the other hand, if the wedge ring and/or slip ring are not dissolvable (for example, if only a dissolvable ball is used to close the bore), then they (e.g. one or both) may instead have a bore (e.g. an inner diameter) which is sufficiently large in the set position/configuration to allow for access to the wellbore (below the set plug seat) via tubing or wireline, such that they do not need to be drilled out to allow for downhole work/production below the set plug seat in the wellbore. And as discussed above, the wedge ring 630 typically has a wedge-like shape (for example, in cross-section), with the outer surface having an angle (for example, with respect to a line parallel to the longitudinal bore centerline) ranging from about 3-20 degrees (or for example alternately, 5-20, 5-10, or 10-20 degrees). And as discussed above, the seat plug of
Upon application of sufficient longitudinal force on the wedge ring 630, for example with the setting tool pressing down on the upper wedge ring 630 directly, the wedge ring 630 moves (e.g. slide longitudinally) further into the slip ring (for example, with most of the length of the wedge ring located within the slip ring), with the wedge-like shape driving the slip ring 620 to deform (plastically and/or elastically) outward to the set configuration/position as shown in
One or more of the plug seat device embodiments described above may allow for an improved method of fracturing a well, especially for example when used in conjunction with a dissolvable ball/plug. Typically, such a method of performing downhole operations (such as fracing) within a (typically cased) wellbore uses an expandable plug seat (which, for example, might include a slip ring and one or more wedge rings located with respect to the slip ring so that application of sufficient longitudinal force on the wedge rings operates to drive the slip ring radially outward) and includes the step of applying a longitudinal force onto the one or more wedge rings (thereby driving the wedge rings towards one another and/or deeper into the slip ring), thereby deforming (e.g. plastically and/or elastically) the slip ring radially outward into contact with the casing/wellbore (in order to seat the plug seat in the casing/wellbore and/or move the plug seat from the unset position to the set position). In some embodiments, the longitudinal force may be applied to the wedge rings by a wireline-conveyed power charge setting tool (e.g. a wireline pressure setting assembly). Typically, the plug seat might not contain any additional retention elements (such as body lock ring or mandrel) beyond the slip ring and/or wedge ring(s). Additionally, the plug seat typically would not contain a separate ball seat; rather, the ball would be landed directly on the upper wedge ring. So in some embodiments, the plug seat may consist essentially of (or consist of) only the slip ring and one or more wedge rings.
The method may further comprise the step of positioning the plug seat within the wellbore (i.e. locating the plug at the proper location downhole within the wellbore for sealing of the wellbore for fracturing of a zone). Oftentimes, the plug seat may be run downhole in conjunction with a wireline-conveyed power charge setting tool (e.g. a wireline pressure setting assembly) and/or a perforating gun assembly (e.g. all three would be run downhole together at the same time). This may allow for more efficient setting of the plug seat and perforating of the well (reducing the number of separate trips run downhole). Typically, such a method would include making-up a tool string comprising the plug seat, a wireline-conveyed power charge setting tool (e.g. a wireline pressure setting assembly), and/or a perforating gun assembly, and then positioning the plug seat in the wellbore, setting the plug seat using the wireline-conveyed power charge setting tool (e.g. a wireline pressure setting assembly), and perforating the well casing, all in a single trip downhole.
Once the plug seat has been set in the wellbore and the well/casing has been perforated, the wellbore can be sealed to allow for fracturing of the well upstream of the plug seat. Typically, the wedge rings may comprise at least an upper wedge ring located above the slip ring, and the method may further comprise landing (e.g. pumping) a dissolvable ball/plug onto the upper wedge ring (to isolate/seal the downstream section of the well). In other words, the ball typically would land directly on the upper wedge ring, without a separate ball seat. In some embodiments, the ball may be formed of dissolvable material (operable to dissolve over time (for example, approximately 1-5 days) under exposure to elevated temperature (for example a range of approximately 150-250 degrees Fahrenheit) and either brine (for example KCL brine) or acid (for example approximately 2-5 pH range). One example of such a material might be TervAlloy dissolvable metallic material or similar materials sold by Terves, Inc. Another example of such material might be dissolvable polymeric material by Bubbletight LLC. And in some embodiments, the plug seat (or at least portions of the plug seat, such as the one or more wedge rings and/or the seal ring) would be formed of dissolvable material (for example, operable to dissolve over time (for example, approximately 1-5 days) under exposure to elevated temperature (for example a range of approximately 150-250 degrees Fahrenheit) and either brine (for example KCL brine) or acid (for example approximately 2-5 pH range). Again, exemplary materials might be TervAlloy or similar materials sold by Terves, Inc., or dissolvable polymeric material by Bubbletight LLC. So, the slip ring and/or one or more wedge rings may be formed of the same dissolvable material as the ball (or in some embodiments, the wedge ring(s) and/or slip ring may be dissolvable, while the ball might not be).
Once the set plug seat has been sealed (isolating the downstream portion of the well), the method might include fracturing a zone of the well above the set and sealed plug seat (e.g. with the ball in place on the upper wedge ring). In most instances, the wellbore in question would comprise a horizontal portion (e.g. a horizontal well), having a toe and a heel. Typically, the initial plug seat is set towards the toe of the horizontal portion of the well (e.g. farthest downhole). The process (for example, setting a plug seat, perforating the casing, sealing the plug seat with a dissolvable ball/plug, and fracturing the zone) typically would be repeated one or more times from the toe of the horizontal portion of the well towards the heel. Then, the ball and/or plug seat would dissolve (over about 1-5 days, due to exposure to well conditions (e.g. elevated temperature, acid and/or brine), without the need for drilling to open the wellbore). In other words, the wellbore might be accessed downstream of the location of the set plug seat(s) via tubing and/or wireline without drilling the ball and/or plug seat (due to the dissolvable nature of the ball and/or plug seat), allowing production of the well without drilling the ball and/or plug seat.
Once the well has been perforated (and the tool string, for example having the setting tool and or perforating gun, has been removed), a dissolvable ball 450 might be dropped and pumped downhole until it is seated on the plug seat 410 (as shown in
While various embodiments in accordance with the principles disclosed herein have been shown and described above, modifications thereof may be made by one skilled in the art without departing from the spirit and the teachings of the disclosure. The embodiments described herein are representative only and are not intended to be limiting. Many variations, combinations, and modifications are possible and are within the scope of the disclosure. Alternative embodiments that result from combining, integrating, and/or omitting features of the embodiment(s) are also within the scope of the disclosure. And logic flows for methods do not necessarily require the particular order shown, or sequential order, to achieve desirable results. Other steps may be provided, or steps may be eliminated, from the described flows/methods, and other components may be added to, or removed from, the described devices/systems. So, other embodiments may be within the scope of the following claims.
Accordingly, the scope of protection is not limited by the description set out above, but is defined by the claims which follow, that scope including all equivalents of the subject matter of the claims. In the claims, any designation of a claim as depending from a range of claims (for example #-##) would indicate that the claim is a multiple dependent claim based of any claim in the range (e.g. dependent on claim # or claim ## or any claim therebetween). Each and every claim is incorporated as further disclosure into the specification and the claims are embodiment(s) of the present invention(s). Furthermore, any advantages and features described above may relate to specific embodiments, but shall not limit the application of such issued claims to processes and structures accomplishing any or all of the above advantages or having any or all of the above features.
Additionally, the section headings used herein are provided for consistency with the suggestions under 37 C.F.R. 1.77 or to otherwise provide organizational cues. These headings shall not limit or characterize the invention(s) set out in any claims that may issue from this disclosure. Specifically and by way of example, although the headings might refer to a “Field,” the claims should not be limited by the language chosen under this heading to describe the so-called field. Further, a description of a technology in the “Background” is not to be construed as an admission that certain technology is prior art to any invention(s) in this disclosure. Neither is the “Summary” to be considered as a limiting characterization of the invention(s) set forth in issued claims. Furthermore, any reference in this disclosure to “invention” in the singular should not be used to argue that there is only a single point of novelty in this disclosure. Multiple inventions may be set forth according to the limitations of the multiple claims issuing from this disclosure, and such claims accordingly define the invention(s), and their equivalents, that are protected thereby. In all instances, the scope of the claims shall be considered on their own merits in light of this disclosure, but should not be constrained by the headings set forth herein.
Use of broader terms such as comprises, includes, and having should be understood to provide support for narrower terms such as consisting of, consisting essentially of, and comprised substantially of. Use of the term “optionally,” “may,” “might,” “possibly,” and the like with respect to any element of an embodiment means that the element is not required, or alternatively, the element is required, both alternatives being within the scope of the embodiment(s). Also, references to examples are merely provided for illustrative purposes, and are not intended to be exclusive.
Also, techniques, systems, subsystems, and methods described and illustrated in the various embodiments as discrete or separate may be combined or integrated with other systems, modules, techniques, or methods without departing from the scope of the present disclosure. Other items shown or discussed as directly coupled or communicating with each other may be indirectly coupled or communicating through some interface, device, or intermediate component, whether electrically, mechanically, or otherwise. Other examples of changes, substitutions, and alterations are ascertainable by one skilled in the art and could be made without departing from the spirit and scope disclosed herein.
This application is a non-provisional of and claims benefit under 35 U.S.C. §119 to co-pending U.S. Provisional Patent Application Ser. No. 62/067,594, filed on Oct. 23, 2014, and entitled “Expandable Plug Seat”, which is hereby incorporated by reference for all purposes as if reproduced in its entirety.
Number | Date | Country | |
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62067594 | Oct 2014 | US |