Unequal load collet and method of use

A downhole actuation system comprises an actuation mechanism comprising an indicator; a wellbore tubular; and a collet coupled to the wellbore tubular. The collet comprises a collet protrusion disposed on one or more collet springs, and the collet protrusion has a position on the one or more collet springs that is configured to provide a first longitudinal force to the indicator in a first direction and a second longitudinal force to the indicator in a second direction. The first longitudinal force is different than the second longitudinal force.

BACKGROUND

During drilling and upon completion and production of an oil and/or gas wellbore, a workover and/or completion tubular string can be installed in the wellbore to allow for production of oil and/or gas from the well. Current trends involve the production of oil and/or gas from deeper wellbores with more hostile operating environments. Various downhole tools may be installed within the wellbore, rather than at the surface of the wellbore, to provide operational control in deep wells. These remote tools can be activated within a wellbore based on control line signals, hydraulic actuation mechanism, and/or mechanical actuation mechanism. When a mechanically actuated mechanism is used to activate or deactivated a downhole tool, the mechanical force is typically supplied by a tubular string deployed within the wellbore. As the depth of the downhole tool increases, the mechanical force required to actuate to the downhole tool may increase in order to overcome various losses within the wellbore, such as friction along the length of the wellbore between the surface and the downhole tool actuation mechanism. As a result, the force placed on the wellbore tubular can be high. This additional force imposes stresses and strains on the wellbore tubular that may be limited by the operational thresholds of the wellbore tubular itself.

SUMMARY

According to an embodiment, a downhole actuation system comprises an actuation mechanism comprising an indicator; a wellbore tubular; and a collet coupled to the wellbore tubular. The collet comprises a collet protrusion disposed on one or more collet springs, and the collet protrusion has a position on the one or more collet springs that is configured to provide a first longitudinal force to the indicator in a first direction and a second longitudinal force to the indicator in a second direction. The first longitudinal force is different than the second longitudinal force. The wellbore tubular may comprise a drill pipe, a casing, a liner, a jointed tubing, a coiled tubing, or any combination thereof. A ratio of the second longitudinal force to the first longitudinal force may be greater than about 1.1. The first longitudinal force may be in the range of from about 1,000 pounds-force to about 10,000 pounds-force, and the second longitudinal force may be in the range of from about 2,000 pounds-force to about 20,000 pounds-force. The first longitudinal force may be less than a compressive load limit of the wellbore tubular. The second longitudinal force may be less than a tensile load limit of the wellbore tubular. The downhole actuation system may also include a downhole tool coupled to the actuation mechanism, where the actuation mechanism may be configured to produce a movement in the downhole tool through a translation of one or more components of the actuation mechanism. The downhole tool may comprise a device selected from: a plug, a valve, a lubricator valve, a tubing retrievable safety valve, a fluid loss valve, a flow control device, a zonal isolation device, a sampling device, a portion of a drilling completion, a portion of a completion assembly, or any combination thereof.

According to an embodiment, a collet comprises a collet spring; and a collet protrusion disposed on the collet spring. The collet protrusion comprises a first engagement surface and a second engagement surface, and a first distance between the first engagement surface and a center point of the collet spring is less than a second distance between the second engagement surface and the center point of the spring. The collet may also include a plurality of collet springs and a plurality of slots disposed between adjacent collet springs, wherein the plurality of collet springs couples a first end to a second end. The first end or the second end may comprise a tapered guide. The center point of the collet spring may comprise a center of the collet spring or a load center point of the collet spring. The first engagement surface may be located at about the center point of the collet spring. The second distance may be at least about 10% of an overall length of the collet spring. When neither the first distance nor the second distance is zero, a ratio of the second distance to the first distance may be greater than about 1.05. The collet protrusion may be disposed on an inner surface of the collet spring and/or the collet protrusion may be disposed on an outer surface of the collet spring.

According to an embodiment, a method of actuating a downhole tool comprises providing a collet coupled to a wellbore tubular, wherein the collet comprises a collet protrusion disposed on a collet spring; providing a first longitudinal force to an actuation mechanism in a first direction using the collet; and providing a second longitudinal force to the actuation mechanism in a second direction using the collet, wherein the first longitudinal force is different that the second longitudinal force, and wherein the first longitudinal force and the second longitudinal force are provided as a result of the configuration of the placement of the collet protrusion on the collet spring. The actuation mechanism may be configured to actuate a downhole tool to a first position in response to the first longitudinal force in the first direction, and the actuation mechanism may be further configured to actuate the downhole tool to a second position in response to second longitudinal force in the second direction. Providing the first longitudinal force may comprise engaging a first surface of the collet protrusion with an indicator coupled to the actuation mechanism. The method may also comprise passing the collet by the actuation mechanism in response to the first longitudinal force or the second longitudinal force exceeding a threshold. Passing the collet by the actuation mechanism may comprise applying a radial force to the collet protrusion at the first surface; radially displacing the collet spring through an interference distance; and conveying the collet past the indicator.

DETAILED DESCRIPTION OF THE EMBODIMENTS

In the drawings and description that follow, like parts are typically marked throughout the specification and drawings with the same reference numerals, respectively. The drawing figures are not necessarily to scale. Certain features of the invention may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in the interest of clarity and conciseness.

Unless otherwise specified, any use of any form of the terms “connect,” “engage,” “couple,” “attach,” or any other term describing an interaction between elements is not meant to limit the interaction to direct interaction between the elements and may also include indirect interaction between the elements described. In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . ”. Reference to up or down will be made for purposes of description with “up,” “upper,” “upward,” “upstream,” or “above” meaning toward the surface of the wellbore and with “down,” “lower,” “downward,” “downstream,” or “below” meaning toward the terminal end of the well, regardless of the wellbore orientation. As used herein, a “compressive load” on a wellbore tubular refers to a load in a downward direction that acts to compress a wellbore tubular. As used herein, a “tensile load” on a wellbore tubular refers to a load in an upward direction that act to place a wellbore tubular in tension. Reference to a longitudinal force means a force substantially aligned with the direction of the longitudinal axis of the wellbore, and reference to a radial force means a force substantially aligned with the radial direction of the wellbore (i.e., a direction substantially normal to the longitudinal axis). The various characteristics mentioned above, as well as other features and characteristics described in more detail below, will be readily apparent to those skilled in the art with the aid of this disclosure upon reading the following detailed description of the embodiments, and by referring to the accompanying drawings.

Disclose herein are devices, systems, and methods for actuating an actuation mechanism using a unequal load collet, which may be configured to provide one force to actuate a device in a first direction and a different force to actuate the device in a second direction. Referring toFIG. 1, an example of a wellbore operating environment in which a collet200and actuation mechanism202may be used is shown. As depicted, the operating environment comprises a workover and/or drilling rig106that is positioned on the earth's surface104and extends over and around a wellbore114that penetrates a subterranean formation102for the purpose of recovering hydrocarbons. The wellbore114may be drilled into the subterranean formation102using any suitable drilling technique. The wellbore114extends substantially vertically away from the earth's surface104over a vertical wellbore portion116, deviates from vertical relative to the earth's surface104over a deviated wellbore portion136, and transitions to a horizontal wellbore portion118. In alternative operating environments, all or portions of a wellbore may be vertical, deviated at any suitable angle, horizontal, and/or curved. The wellbore may be a new wellbore, an existing wellbore, a straight wellbore, an extended reach wellbore, a sidetracked wellbore, a multi-lateral wellbore, and other types of wellbores for drilling and completing one or more production zones. Further, the wellbore may be used for both producing wells and injection wells.

A wellbore tubular string120and/or a wellbore tubular string122may be lowered into the subterranean formation102for a variety of drilling, completion, workover, treatment, and/or production processes throughout the life of the wellbore. The embodiment shown inFIG. 1illustrates the wellbore tubular120in the form of a completion assembly string disposed in the wellbore114, and a second wellbore tubular122is illustrated in the form of a wellbore tubular disposed within the wellbore tubular120. It should be understood that the wellbore tubular120and/or the second wellbore tubular122is equally applicable to any type of wellbore tubulars being inserted into a wellbore including as non-limiting examples drill pipe, casing, liners, jointed tubing, and/or coiled tubing. Further, the wellbore tubular120and/or the second wellbore tubular122may operate in any of the wellbore orientations (e.g., vertical, deviated, horizontal, and/or curved) and/or types described herein. In an embodiment, the wellbore may comprise wellbore casing, which may be cemented into place in the wellbore114. In general, the wellbore tubular120and/or the second wellbore tubular122may have a different tensile load limit than a compressive load limit. For example, coiled tubing may be subject to buckling when placed under a given compressive load while being capable of supporting the same load in tension. In an embodiment, the unequal load collet may allow a downhole tool to be actuated using a force in each direction that is within the compressive load limit and the tensile load limit of the wellbore tubular120and/or the second wellbore tubular122used to form the wellbore tubular string. This represents an advantage over previous actuation devices that require the same force in each direction, as one or more of the forces may exceed the tensile load limit and/or the compressive load limit of the wellbore tubular used.

In an embodiment, the wellbore tubular string120may comprise a completion assembly string comprising one or more wellbore tubular types and one or more downhole tools (e.g., zonal isolation devices140, screens, valves124, etc.), including in an embodiment, one or more actuation mechanisms202. In an embodiment, the second wellbore tubular string122may be disposed within the wellbore tubular string120to actuate one or more downhole tools forming a portion of the wellbore tubular string120. The second wellbore tubular string122may comprise the collet200for engaging and actuating the one or more actuation mechanisms202. The one or more downhole tools may take various forms. For example, a zonal isolation device may be used to isolate the various zones within a wellbore114and may include, but is not limited to, a plug, a valve124(e.g., lubricator valve, tubing retrievable safety valve, fluid loss valves, etc.), and/or a packer140(e.g., production packer, gravel pack packer, frac-pac packer, etc.).

The workover and/or drilling rig106may comprise a derrick108with a rig floor110through which the wellbore tubular120extends downward from the drilling rig106into the wellbore114. The workover and/or drilling rig106may comprise a motor driven winch and other associated equipment for extending the wellbore tubular120and/or the second wellbore tubular122into the wellbore114to position the wellbore tubular120and/or the second wellbore tubular122at a selected depth. While the operating environment depicted inFIG. 1refers to a stationary workover and/or drilling rig106for conveying the wellbore tubular120and/or the second wellbore tubular122comprising the collet200within a land-based wellbore114, in alternative embodiments, mobile workover rigs, wellbore servicing units (such as coiled tubing units), and the like may be used to lower the outer wellbore tubular120and/or the second wellbore tubular comprising the collet200into the wellbore114. It should be understood that a wellbore tubular120and/or a second wellbore tubular122may alternatively be used in other operational environments, such as within an offshore wellbore operational environment.

Regardless of the type of operational environment in which the collet200and actuation mechanism202are used, it will be appreciated that collet200and actuation mechanism202serve to actuate a downhole device using one force in a first direction and a different force in a second direction. For example, the collet200and an actuation mechanism202may be used to open a downhole valve124using a first force (e.g., a first longitudinal force) and then close the valve124using a second force (e.g., a second longitudinal force) in a second direction, where the second force may be greater than the first force and the second direction may be different than the first direction. As described in greater detail with reference toFIGS. 2A,2B, and3, the collet200comprises a first end208, a second end210, a plurality of collet springs204with a plurality of slots212disposed there between, and a collet protrusion206. The collet protrusion206may engage an indicator304on the actuation mechanism202and apply a longitudinal force to the indicator304to actuate the downhole tool or device. The actuation mechanism202may comprise a portion of the downhole tool or device configured to be operated through an engagement with the collet200and/or a separate component from the downhole tool or device that is coupled to and configured to actuate the downhole tool or device.

An embodiment of the collet200is shown inFIGS. 2A and 2Bin the configuration in which it may be conveyed into the wellbore114. The first end208of the collet200generally comprises a tubular mandrel or means. The outer diameter of the first end208may be sized to allow the collet200to be conveyed within the wellbore and/or within one or more wellbore tubulars disposed within the wellbore. A longitudinal fluid passage214extends through the first end208to allow for the passage of fluids and/or other components (e.g., one or more additional wellbore tubulars) through the collet200. The first end208of the collet200may be coupled to a wellbore tubular by any known connection means. In an embodiment, the collet200may be coupled to a wellbore tubular by a threaded connection formed between the wellbore tubular and the first end208. In other embodiments, the first end208of the collet200may be coupled to a wellbore tubular through the use of one or more connection mechanisms such as a screw (e.g., a set screw), a bolt, a pin, a weld, and/or the like. In an embodiment, one or more screws (e.g., set screws) may be disposed in one or more holes216, which may comprise corresponding threads, in the first end208of the collet200to couple the collet200to a wellbore tubular120.

In an embodiment, the second end210of the collet200may also generally comprise a tubular mandrel or means. The outer diameter of the second end210may be sized to allow the collet200to be conveyed within the wellbore and/or within one or more wellbore tubulars disposed within the wellbore. The longitudinal fluid passage214extends from the first end208through the second end210to allow for the passage of fluids and/or other components (e.g., one or more additional wellbore tubulars) through the collet200. The second end210of the collet200may be coupled to a wellbore tubular by any known connection means. In an embodiment, the second end210of the collet200may be coupled to a wellbore tubular by a threaded connection formed between the wellbore tubular and the second end210. In other embodiments, the second end210of the collet200may be coupled to a wellbore tubular through the use of one or more connection mechanisms such as a screw, a bolt, a pin, a set screw, a weld, and/or the like. In some embodiments, the second end210of the collet200may not be coupled to a wellbore tubular. Rather, the second end210may be configured to form a guide to aid in directing the collet200and the wellbore tubular120coupled to the collet200through the interior of the wellbore and/or a wellbore tubular. In an embodiment, the second end210may form a tapered guide (e.g., a mule shoe guide) with an end disposed at a non-normal angle to the longitudinal axis (i.e., axis X ofFIG. 2A) of the wellbore. In an embodiment, the second end210may not form a guide, but the second end210may be coupled to a guide using a threaded connection and/or another connection mechanism. In still other embodiments, the second end210may not form a guide or be coupled to a guide.

In an embodiment as shown inFIG. 6C(described in more detail herein), the collet200may be disposed about a mandrel650. The mandrel650may pass through the first end208and the second end210through the longitudinal fluid passageway214. The diameter and configuration of the mandrel650may allow for radial compression and/or expansion of the collet200due to an interaction with an indicator. One or more features652,654may engage the first end208and/or the second end210to maintain the collet200in position on the mandrel650. For example, one or more collars (e.g., stop collars) may be disposed above and/or below the collet200to limit the relative longitudinal movement of the collet200about the mandrel650. In this configuration, the collet200may be slidingly engaged with the mandrel650. In an embodiment, the mandrel650may be a separate component coupled to the wellbore tubular120and/or the second wellbore tubular122, or alternatively, the mandrel may comprise a portion of the wellbore tubular120and/or the second wellbore tubular122. Various other configurations are possible for conveying the collet200within the wellbore on a wellbore tubular and/or as part of a wellbore tubular string.

Returning to the embodiment shown inFIGS. 2A,2B, and3, the collet200comprises one or more springs204(e.g., beam springs) and/or spring means separated by slots212. In some contexts, the springs204may be referred to as collet fingers204. The springs204couple the first end208of the collet200to the second end210of the collet200. The springs204may be configured to form a generally cylindrical configuration about the longitudinal fluid passage214, which may result from cutting the slots212from a single cylindrical mandrel to form the first end208, the one or more springs204and the second end210.

The one or more springs204may be configured to allow for a limited amount of radial compression of the springs204in response to a radially compressive force, and/or a limited amount of radial expansion of the springs204in response to a radially expansive force. The radial compression and/or expansion may allow the collet and the collet protrusion206to pass by a restriction in a wellbore and/or in a wellbore tubular while returning to the original diameter once the collet has moved past the restriction. The amount of radial expansion and/or compression may depend on various factors including, but not limited to, the properties of the springs204(e.g., geometry, length, cross section, moments, etc.), the radial force applied, and/or the material used to form the springs204. In addition to these factors, the force required to produce a given amount of radial expansion and/or contraction depends on the location of the applied force along the length of the spring204. For a spring of constant cross section, the greatest radial expansion and/or compression for a given force generally occurs when the force is applied at the center of the spring (e.g., the location approximately half way between a first end of the spring204adjacent the first end208of the collet200and a second end of the spring204adjacent the second end210of the collet200). As the applied force moves away from the center point of the spring, the amount of radial expansion and/or contraction decreases by an amount generally predictable using a variety of known techniques such as beam theory, where the spring is modeled as a beam. This concept may be restated in terms of the force required to provide a given amount of radial expansion and/or compression. In general, the force required to produce a given amount of radial expansion and/or contraction is the least when the amount of expansion and/or contraction is generated at the center point of the spring, and the force required to produce the given amount of radial expansion and/or contraction increases as the point of expansion and/or contraction moves away from the center point of the spring.

For springs having a non-constant cross section, beam theory may be used to predict and/or determine the point on the spring requiring the least amount of radial force to produce a given amount of radial expansion and/or contraction. This point may be referred to herein as the load center point, which may correspond to the center of the spring for a spring of constant cross section and may vary from the center of the spring for springs having non-constant cross sections. The force required to produce a given amount of radial expansion and/or contraction may increases as the point of expansion and/or contraction moves away from the load center point. These concepts may be used to design the collet protrusion206as described in more detail herein.

In an embodiment, the collet200comprises one or more cuts forming slots212between the plurality of springs204. The slots212may allow the collet protrusion206to at least partially compress inward (i.e., radially compress) in response to a radially compressive force and/or at least partially expand outwards (i.e., radially expand) in response to a radially expansive force, as described in more detail below. In an embodiment, the slots212may comprise longitudinal slots, angled slots (as measured with respect to the longitudinal axis X), helical slots, and/or spiral slots for allowing at least some radial compression in response to a radially compressive force. The configuration of the slots212(e.g., their shape, width, length, orientation, and/or dimensions relative to the dimensions of the springs) may be designed to determine the spring characteristics of the springs204and the corresponding configuration and properties of the collet protrusion206.

The collet200also comprises a collet protrusion206disposed on the outer surface of one or more of the plurality of springs204. In an embodiment, the collet protrusion206may be disposed on only one of the springs204, a portion of the plurality of springs204, or all of the springs204. The collet protrusion206is configured to engage an indicator304and thereby produce a longitudinal force (i.e., a force substantially parallel to the axis X) on the indicator304and a radial force (e.g., a radially compressive force and/or a radially expansive force) on the springs204. In an embodiment, the collet protrusion206may be configured to engage the indicator304at a plurality of surfaces or points and thereby produce the corresponding longitudinal and radial forces at a plurality of points along the length of the springs204. The configuration of the collet protrusion206may be used to determine the force required to move the collet200past the indicator304in each direction, as described in more detail herein.

As shown inFIGS. 2A,2B, and3, the collet protrusion206generally comprises a section of the springs204with an increased outer diameter. The one or more collet protrusions206on the one or more springs204may extend around the outer surface of the springs204, and as part of the springs204, the one or more slots212may extend between adjacent collet protrusions206. The collet protrusion206may comprise one or more surfaces218,220for engaging and/or contacting the indicator304disposed on an outer wellbore tubular302and/or a component thereof such as a downhole tool or actuation mechanism202. In some contexts, the surfaces218,220may be referred to as engaging surfaces218,220. In an embodiment, the surfaces218,220may be disposed at generally obtuse angles with respect to the angle between the outer surface306of the springs204and the surfaces218,220as measured in a longitudinal direction (i.e., along axis X). This angle may allow for a radially compressive force to be applied to the springs204when the collet protrusion206contacts the corresponding indicator304on the outer wellbore tubular302. In an embodiment, the angle between outer surface306of the springs204and the surfaces218,220may be greater than 90 degrees and less than 180 degrees. In an embodiment, the angle between the outer surface306of the springs204and the surfaces218,220may be about 100 degrees, about 110 degrees, about 120 degrees, about 130 degrees, about 135 degrees, about 140 degrees, about 150 degrees, about 160 degrees, or about 170 degrees. The angle between the outer surface306of the springs204and the surface218may be the same or different than the angle between the outer surface306of the springs204and the surface220. In some embodiments, more than two surfaces may be present on one or more collet protrusions206. In this embodiment, each of the surfaces may have the same or different angles between the outer surface306of the springs204and the corresponding surface. In an embodiment, the edges formed between the surfaces218,220and the outer surface of the collet protrusion206may be rounded or otherwise beveled to aid in the movement of the collet protrusion206past the indicator304.

The indicator304is coupled to a wellbore tubular302and/or as a part of a downhole tool or actuation mechanism. The indicator304is configured to engage the collet protrusion206to produce the longitudinal and radial forces at one or more points along the springs204. The indicator304and the wellbore tubular302are generally configured to resist radial movement and may be configured to withstand greater radial compressive and/or radial compressive loads than the springs204of the collet200. The downhole tool and/or actuation mechanism may be configured to allow for an amount of longitudinal translation in response to an applied longitudinal force resulting from the engagement of the collet200and the indicator304. As a result, the engagement between the collet protrusion206and the indicator304may produce an amount of longitudinal translation of the indicator304and/or the actuation mechanism followed by a radial expansion and/or a radial compression of the springs204to allow the collet200to pass by the indicator304.

In an embodiment, the indicator304generally comprises a section of the wellbore tubular302and/or a component thereof with a decreased inner diameter. In other embodiments as described in more detail below, the indicator304comprises a section of the wellbore tubular302and/or a component thereof with an increased outer diameter and the collet may pass outside the wellbore tubular. The indicator304may comprise one or more surfaces308,310for contacting the surfaces218,220of the collet protrusion206. In an embodiment, the surfaces308,310may be disposed at generally obtuse angles with respect to the angle between the inner surface318of the wellbore tubular302and the surfaces308,310as measured in a longitudinal direction (i.e., along axis X). This angle may allow for a radially compressive force to be applied to the springs204when the collet protrusion206engages the indicator304. In an embodiment, the angle between inner surface318of the wellbore tubular302and the surfaces308,310may correspond to the angle of the surfaces218,220on the collet protrusion206. In general, angle between inner surface318of the wellbore tubular302and the surfaces308,310may be about 100 degrees, about 110 degrees, about 120 degrees, about 130 degrees, about 135 degrees, about 140 degrees, about 150 degrees, about 160 degrees, or about 170 degrees. The angle between the inner surface318of the wellbore tubular302and the surface308may be the same or different than the angle between the inner surface318of the wellbore tubular302and the surface310. In an embodiment, the edges formed between the surfaces308,310and the inner surface of the indicator304may be rounded or otherwise beveled to aid in the movement of the collet protrusion206past the indicator304.

The collet protrusion206may generally have a height312configured to engage the indicator304. As used herein the height312of the collet protrusion206may refer to the radial distance that the outer surface307of the collet protrusion206extends beyond the surface306of the corresponding spring204. Similarly, the indicator304may have a height314sufficient to allow for an engagement with the collet protrusion206. The interference distance316represents the amount of radial overlap between the collet protrusion206and the indicator304, and is the amount by which the collet spring204must be displaced in order to allow the collet to pass by the indicator. The interference distance316can be chosen through a selection of the height314of the indicator304and/or the height312of the collet protrusion206. As noted above, the force required to radially compress and/or radially expand the springs204through the interference distance316may be based on the properties of the springs and the interference distance316through which the collet is radially compressed or expanded. In an embodiment, a desired force may be achieved through a selection of the properties of the springs204and the interference distance316. In an embodiment, the interference distance316may range from about 0.001 inches to about 0.5 inches, alternatively about 0.02 inches to about 0.2 inches, or alternatively about 0.03 inches to about 0.1 inches.

The radial compression and/or radial expansion of the springs204through the interference distance316results from the engagement of a surface (e.g., surface308) of the indicator304with a surface (e.g., a surface218) of the collet protrusion206. At a first point320of engagement between the indicator304and the collet protrusion206corresponding to a first surface218, a portion of the force resulting from the engagement between the corresponding surfaces is directed in a longitudinal direction (i.e., along axis X) and a portion of the force is directed in a radial direction. In an embodiment, the portion of the force directed along the longitudinal direction may be transferred to an actuation mechanism to actuate one or more downhole tools or components. When the longitudinal resistance of the indicator304rises above a threshold (e.g., when the actuation mechanism moves to an actuated state, for example reaching a stop or a maximum translation position), the radial force may also increase. As the radial force applied to the spring204at the first point320of engagement exceeds a first force required to displace the spring204through the interference distance316, the collet protrusion206may pass by the indicator304.

Similarly, when the collet200is conveyed in a second direction, a surface (e.g., surface310) of the indicator304may engage a surface of the collet protrusion206at a second point322of engagement corresponding to surface220. The longitudinal force resulting from the engagement of the indicator304with the collet protrusion206may be transferred to the actuation mechanism to actuate one or more downhole tools or components. When the longitudinal resistance of the indicator304rises above a threshold (e.g., when the actuation mechanism moves to an actuated state), the radial force may also increase. As the radial force applied to the spring204at the second point322of engagement exceeds a second force required to displace the spring204at the second point322through the interference distance316, the collet protrusion206may pass by the indicator304.

In an embodiment, the selection of the location of the surfaces of the collet protrusion206, and therefore the points (e.g., the first point320and/or the second point322) at which the collet protrusion206engages the indicator304, may allow one force to be applied to the indicator304in a first direction and a different force to be applied to the indicator304in a second direction. As discussed above, the force required to radially compress and/or expand the spring a given distance (e.g., the interference distance316) at a given point is generally the least at the center point and/or the load center point of the spring204. As the point of radial compression and/or radial expansion moves away from the center point and/or load center point of the spring204, the force required to radially compress and/or expand the spring204the given distance (e.g., the interference distance316) increases. This principle may be used to configure the collet protrusion206to provide one force (e.g., one longitudinal force) in a first direction and a different force (e.g., a different longitudinal force) in a second direction for actuating an actuation mechanism.

In an embodiment, the second surface220corresponding to a second point322may be located at approximately a center point (e.g., the center224and/or load center point) of the spring204. The first surface218corresponding to the first point320may be located a longitudinal distance324away from the second surface220. As a result of this configuration, the amount of longitudinal force that can applied and/or the amount of longitudinal resistance that can be encountered prior to exceeding the radial force required to displace the spring204through the interference distance316may be higher at the first surface218than at the second surface220.

In another embodiment, the first surface218corresponding to a first point320may be located at approximately a center point (e.g., the center224and/or load center point) of the spring204. The second surface220corresponding to the second point322may be located a longitudinal distance324away from the first surface218. As a result of this configuration, the amount of longitudinal force that can applied and/or the amount of longitudinal resistance that can be encountered prior to exceeding the radial force required to displace the spring204through the interference distance316may be higher at the second surface220than at the first surface218.

In an embodiment, the distance324between the first surface218and the second surface220may be selected to provide a configuration and location of the collet protrusion206and corresponding surfaces218,220requiring a lower force to radially compress and/or radially expand the springs204upon engagement with the indicator304at one surface (e.g., the first surface218) as compared to another surface (e.g., the second surface220). In an embodiment in which the second surface220is located at the center point224of the spring204, the distance324may be at least about 10%, about 20%, about 30%, or about 40% of the overall length of the spring204between the first end208and the second end210of the collet200. In an embodiment in which the first surface218is located at the center point224of the spring204, the distance324may be at least about 10%, about 20%, about 30%, or about 40% of the overall length of the spring204between the first end208and the second end210of the collet200.

In an embodiment, neither the first surface218nor the second surface220may be located at the center point224of the spring204. A longitudinal force differential may be achieved between a first surface218and a second surface220by configuring the distance between the first surface218and the center point of the spring204to be different than the distance between the second surface220and the center point224of the spring204. In an embodiment, the distance between the first surface218and the center point of the spring204to be less than the distance between the second surface220and the center point224of the spring204. In an embodiment in which neither the first surface218nor the second surface220are located at the center point224of the beam, the ratio of the distance between the second surface220and the center point of the spring204to the distance between the first surface218and the center point224of the spring204may be greater than about 1.05, greater than about 1.1, greater than about 1.2, greater than about 1.3, greater than about 1.4, greater than about 1.5, greater than about 1.6, greater than about 1.7, greater than about 1.8, greater than about 1.9, or greater than about 2.0.

In an embodiment, the configuration of the locations of the surfaces (e.g., the first surface218and/or the second surface220) at which the collet protrusion206engages the indicator304may allow a first longitudinal force to be applied to an actuation mechanism in a first direction and a second longitudinal force to be applied to the actuation mechanism in a second direction. In an embodiment, the first longitudinal force may be different than the second longitudinal force. In an embodiment, the first longitudinal force may be greater than the second longitudinal force, or the second longitudinal force may be greater than the first longitudinal force. In an embodiment, the collet protrusion206and the corresponding engagement surfaces may be configured to provide a ratio of the second longitudinal force to the first longitudinal force of greater than about 1.1, greater than about 1.2, greater than about 1.3, greater than about 1.4, greater than about 1.5, greater than about 1.6, greater than about 1.7, greater than about 1.8, greater than about 1.9, greater than about 2.0, or greater than about 2.5. In an embodiment, the first longitudinal force may range from about 1,000 pounds-force to about 10,000 pounds-force, alternatively about 2,500 pounds-force to about 7,500 pounds-force, or alternatively about 3,000 pounds-force to about 6,000 pounds-force. The second longitudinal force may range from about 2,000 pounds-force to about 20,000 pounds-force, alternatively about 5,000 pounds-force to about 15,000 pounds-force, alternatively about 7,500 pounds-force to about 12,500 pounds-force, or alternatively about 9,000 pounds-force to about 11,000 pounds-force.

In an embodiment, the first longitudinal force may be less than or equal to a compressive load limit of the wellbore tubular coupled to the collet. In an embodiment, the first longitudinal force may be less than about 99%, less than about 95%, less than about 90%, less than about 80%, or alternatively less than about 70% of the compressive load limit of the wellbore tubular coupled to the collet. In an embodiment, the second longitudinal force may be less than or equal to a tensile load limit of the wellbore tubular coupled to the collet. In an embodiment, the second force may be less than about 99%, less than about 95%, less than about 90%, less than about 80%, or alternatively less than about 70% of the tensile load limit of the wellbore tubular coupled to the collet.

In addition to the embodiment of the collet described with respect toFIGS. 2A,2B, and3, another embodiment of the collet is shown inFIGS. 4 and 5. The collet400illustrated inFIGS. 4 and 5is similar to the collet200illustrated inFIGS. 2A,2B, and3, and similar components may be the same or similar to those described with respect toFIGS. 2A,2B, and3. The collet400comprises a first end408, a second end410, a plurality of collet springs404with a plurality of slots412disposed there between, and a longitudinal fluid passage414extending through the collet400. The collet400also comprises a collet protrusion406disposed on an inner surface of the springs404that may interact with an indicator disposed on an outer surface of a wellbore tubular502. Since the collet protrusion406is disposed on an inner surface of the springs404, this embodiment may be referred to in some contexts as an inverted collet.

The one or more springs404may be configured to allow for a limited amount of radial expansion in response to a radially expansive force during the engagement of the collet protrusion406with one or more surfaces506,510of an indicator504. The indicator504may be coupled to an outer surface of a wellbore tubular502and/or as a part of a downhole tool or actuation mechanism. The indicator504is configured to engage the collet protrusion406to produce longitudinal and radial forces at one or more points along the springs404. The indicator504and the wellbore tubular502are generally configured to resist radial movement and may be configured to withstand greater radial compressive loads than the springs404of the collet400. As a result, the engagement between the collet protrusion406and the indicator504may produce a radial expansion of the springs404through an interference distance516rather than a radial expansion of the wellbore tubular502when the longitudinal resistance is above a threshold. Any of the considerations relative to configuring the location of the surfaces418,420of the collet protrusion406relative to the center point424of the spring may be applied to the collet400to allow a downhole device to be actuated with one force in a first direction and a different force in a second direction, as was discussed previously with respect toFIGS. 2A,2B, and3and collet200.

Still another embodiment of a collet is illustrated inFIGS. 6A,6B,6C, and7. The collet600illustrated inFIGS. 6A,6B,6C, and7is similar to the collet200illustrated inFIGS. 2A,2B, and3, and similar components may be the same or similar to those described with respect toFIGS. 2A,2B, and3. The collet600comprises a first end608, a second end610, a plurality of collet springs604with a plurality of slots612disposed there between, and a longitudinal fluid passage614extending through the collet600. The collet600also comprises a collet protrusion606disposed on an outer surface of the springs604that may interact with an indicator702disposed on an inner surface of a wellbore tubular702.

The collet protrusion606is configured to engage the indicator704and thereby produce a longitudinal force on the indicator704and a radial force (e.g., a radially compressive force) on the springs604. In an embodiment, the collet protrusion606may be configured to engage the indicator704at any of a plurality of surfaces and thereby produce the corresponding longitudinal and radial forces at a plurality of points along the length of the springs604. The configuration of the collet protrusion606may be used to determine the longitudinal force applied to the indicator704and the radial force required to move the collet600past the indicator704in each direction.

As shown inFIGS. 6A,6B,6C, and7, the collet protrusion206generally comprises a section of the springs604with an increased outer diameter. The collet protrusion606may comprise two raised portions622,624having an increased outer diameter and a central portion626having an increased outer diameter relative to the outer surface of the springs604, and an outer diameter that may be less than the two portions622,624(e.g., forming a protrusion having a recessed central portion). In an embodiment, the outer diameter of the central portion626may be configured to allow the indicator704to pass by the central portion626without engaging the central portion626. The collet protrusion606may comprise one or more surfaces618,620,726,728for contacting an indicator704disposed on an outer wellbore tubular702through which the collet600passes. In an embodiment, the surfaces726,728may be disposed at generally obtuse angles with respect to the angle between the outer surface706of the springs604and the surfaces726,728as measured in a longitudinal direction. The angles of the surfaces726,728may be selected to allow the indicator704to pass over the surfaces726,728without producing a longitudinal force sufficient to actuate an actuation mechanism. In an embodiment, the an the angle between the outer surface706of the springs604and the surfaces726,728as measured in a longitudinal direction may range from about 120 degrees to about 150 degrees. The angles of the surfaces726,728may each be the same or they may be different.

In an embodiment, the surfaces618,620may be disposed at generally obtuse angles with respect to the angle between the outer surface of the central portion626and the surfaces618,620as measured in a longitudinal direction. In an embodiment, the angle between the outer surface of the central portion626and the surfaces618,620as measured in a longitudinal direction may range from great than about 90 degrees to about 120 degrees. The angles of the surfaces618,620may each be the same or they may be different. This angle may allow for a longitudinal force to be applied to the indicator704and a radially compressive force to be applied to the springs604when the surfaces618,620of the respective raised portions624,622contacts the corresponding surface708,710of the indicator704on the outer wellbore tubular702. In an embodiment, the edges formed between the surfaces618,620and the outer surface of the corresponding raised portions624,622may be rounded or otherwise beveled to aid in the movement of the collet protrusion606past the indicator704.

The radial compression of the springs604through the interference distance716results from the engagement of a surface708,710of the indicator704with a surface618,620,726,728of the collet protrusion606. At a point of engagement between a surface708,710of the indicator704and a surface618,620,726,728of the collet protrusion606, a portion of the resulting force between the corresponding surfaces is directed in a longitudinal direction and a portion of the force is directed in a radial direction. The portion of the force directed in the longitudinal and radial directions is based, at least in part, on the angle of the surfaces. In general, as the angle between the outer surface706of the springs604and the surfaces618,620,726,728increases, a greater portion of the force is directed in the radial direction and less of the force is directed in the longitudinal direction. In an embodiment, the angle between the outer surface706of the springs604and the surfaces726,728may be selected so that the radially directed portion of the force resulting from the engagement of the collet600with the indicator704is sufficient to radially compress the springs604through the interference distance716rather than actuate an actuation mechanism in a longitudinal direction. This may allow the indicator704to pass into radial alignment with the central portion626of the collet protrusion606prior to actuation of an actuation mechanism.

In an embodiment, the angle between the outer surface of the central portion626and the surfaces618,620may be selected so that the engagement between the surfaces618,620and the indicator704may produce a sufficient portion of the force directed in the longitudinal direction to actuate an actuation mechanism coupled to one or more downhole tools or components. When the longitudinal resistance of the indicator704rises above a threshold (e.g., when the actuation mechanism moves to an actuated state), the radial force applied to the spring604at the corresponding point720,722of engagement may exceed the radial force required to displace the spring604through the interference distance716. The corresponding raised portion622,624of the collet protrusion606may then pass by the indicator704. In an embodiment, the selection of the location of the surfaces618,620of the collet protrusion606, and therefore the points (e.g., the first point720and/or the second point722) at which the collet protrusion606engages the indicator704, may allow a one longitudinal force to be applied to the actuation mechanism in a first direction and a different longitudinal force to be applied to the actuation mechanism in a second direction. Any of the considerations and resulting force differentials discussed with respect the collet200also apply to the selection of the locations of the surfaces618,620of the collet600.

Returning toFIGS. 2A,2B, and3, the indicator304may form a portion of an actuation mechanism for actuating a downhole tool or component. The actuation mechanism may generally be configured to produce a movement in a downhole tool through a translation of one or more components of the actuation mechanism. As discussed above, the translation may be a longitudinal translation and may be achieved through the engagement of the indicator with one or more surfaces of the collet protrusion206. The surfaces218,220of the collet200may be configured to provide one longitudinal force to actuate an actuation mechanism in a first direction and a different longitudinal force to actuate the actuation mechanism in a second direction. The corresponding actuation mechanism may be configured to actuate in response to one longitudinal force in a first direction and the different longitudinal force in the second direction. Any of a variety of actuation mechanisms comprising a feature configured to act as an indicator304may be used with the collet disclosed herein. In an embodiment, the actuation mechanisms may be coupled to and configured to actuate one or more devices including, but not limited to, a plug, a valve (e.g., a lubricator valve, tubing retrievable safety valve, fluid loss valves, etc.), a flow control device (e.g., a shifting sleeve, a selective flow device, etc.), a zonal isolation device (e.g., a plug, a packer such as a production packer, gravel pack packer, frac-pac packer, etc.), a sampling device, a portion of a drilling completion, a portion of a completion assembly, and any other downhole tool or component that is configured to be mechanically actuated by the translation of one or more components.

In an embodiment, the actuation mechanism may be coupled to a valve such as a ball valve. As shown inFIG. 8, an embodiment of a ball valve800may generally comprise a variety of components to provide a seal (e.g., a ball/seat interface) and an actuation mechanism to actuate the ball valve800. While an exemplary actuation mechanism and process is described with respect to a ball valve assembly, it is expressly understood that the actuation mechanism providing the longitudinal translation may be used with any of a variety of downhole tools.

In an embodiment, the ball valve800assembly may comprise two cylindrical retaining members802,804on opposite sides of the ball806. One or more seats or seating surfaces may be disposed above and/or below the ball806(e.g., within or engaging cylindrical retaining member802and/or cylindrical retaining member804) to provide a fluid seal with the ball806. The ball806generally comprises a truncated sphere having planar surfaces810on opposite sides of the sphere. Planar surfaces810may each have a projection812(e.g., cylindrical projections) extending outwardly therefrom, and a radial groove814extending from the projection812to the edge of the planar surface810.

An actuation mechanism may comprise or may be coupled to an actuation member808having two parallel arms816,818that are positioned about the ball806and the retaining members802,804. In an embodiment, the actuation member808may comprise an indicator832disposed on the upper side of the ball806. In some embodiments, the actuation member808may be coupled to a separate actuation mechanism comprising an indicator on the upper side of the ball806. The actuation member808may be aligned such that arms816,818are in a plane parallel to that of planar surfaces810. Projections812may be received in windows820,822through each of the arms816,818. Actuation pins824may be provided on each of the inner sides of the arms816,818. Pins824may be received within the grooves814on the ball806. Bearings826may be positioned between each pin824and groove814, and a support member830may engage a projection812within the respective windows820,822.

In the open position, the ball806is positioned so as to allow flow of fluid through the ball valve800by allowing fluid to flow through an interior fluid passageway828(e.g., a bore or hole) extending through the ball806. During operation, the ball806is rotated about rotational axis Y such that interior flow passage828is rotated out of alignment with the flow of fluid, thereby forming a fluid seal with one or more seats or seating surfaces and closing the valve. The interior flow passage828may have its longitudinal axis disposed at about 90 degrees to the axis X when the ball is in the closed position and the longitudinal axis may be aligned with the axis X when the ball is in the open position. The ball806may be rotated by longitudinal movement of the actuation member808along axis X. The pins824move as the actuation member808moves, which causes the ball806to rotate due to the positioning of the pins824within the grooves814on the ball806.

With reference toFIGS. 1 and 8, the ball valve800and its associated components can be disposed within a wellbore114as a portion of the wellbore tubular string120. In an embodiment, the ball valve800may comprise a sub-surface safety valve, a fluid loss valve, and/or a lubricator valve. In order to actuate the ball valve800from a closed position to an open position, a second wellbore tubular string122comprising a collet200as described herein may be disposed within the wellbore tubular string120comprising the ball valve800. As the second wellbore tubular string122is conveyed within the wellbore tubular string120, the collet200may be conveyed into proximity with the indicator832of the ball valve.

As shown inFIG. 3, the indicator832on the actuation member808may represent the indicator304with the upper portion of the wellbore on the left side ofFIG. 3. As the collet200approaches the indicator304from the upper side of the ball valve800, the surface220of the collet protrusion206may engage the surface310of the indicator304at a corresponding point320. A force may be applied to the collet200to the point of engagement through the second wellbore tubular122from the surface of the wellbore114. A portion of this force is directed in a longitudinal direction (i.e., along axis X) and a portion of the force is directed in a radial direction. In an embodiment, the longitudinal portion of the force may be transferred to an actuation member808to actuate the ball valve800. As this first force is applied in the longitudinal direction, the actuation member808may move down along the axis X. The pins824move as the actuation member808moves along the axis X, which causes the ball806to rotate due to the positioning of the pins824within the grooves814on the ball806. The actuation member808may move down until the upper surface of the windows820,822contacts the edge of the protrusions on the support member830to rotate the ball806to the open position. At this point, the actuation member808may be constrained from further downward movement and the longitudinal resistance may be characterized as exceeding a threshold. Subsequent force applied to the collet200through the second wellbore tubular122may result in the radial force applied to the spring204at the point322of engagement exceeding a force required to displace the spring204through the interference distance316, thereby allowing the collet protrusion206to pass by the indicator304. The second wellbore tubular122comprising the collet200may then be conveyed through the interior fluid passageway828of the ball806, which may allow for one or more fluids to be produced from the wellbore and/or a wellbore servicing fluid to be pumped into the wellbore formation (e.g., from a zone located below the ball valve) through the second wellbore tubular122.

Upon conveying the second wellbore tubular122out of the wellbore114, the collet may pass through the interior fluid passageway828of the ball806and engage the lower side of the indicator832. Again referring to the indicator304illustrated inFIG. 3as representing the indicator832, a surface308of the indicator304may engage a surface218of the collet protrusion206at a point320of engagement corresponding to surface218. The longitudinal force resulting from the engagement of the indicator304with the collet protrusion206may be transferred to the actuation member808of the ball valve800. Due to the configuration of the surface218, the longitudinal force applied to the actuation member808is different than the longitudinal force applied to open the ball valve800. As this second longitudinal force is applied to the indicator304, the actuation member808may move up along the axis X. The pins824move as the actuation member808moves along the axis X, which causes the ball806to rotate due to the positioning of the pins824within the grooves814on the ball806. The actuation member808may move up until the lower surface of the windows820,822contacts the edge of the protrusions on the support member830to the closed position (e.g., closing the ball valve800and shutting in the well below the valve). At this point, the actuation member808may be constrained from further upward movement and the longitudinal resistance may be characterized as exceeding a threshold. Subsequent force applied to the collet200through the second wellbore tubular122may result in the radial force applied to the spring204at the point320of engagement exceeding a force required to displace the spring204through the interference distance316, thereby allowing the collet protrusion206to pass by the indicator304. The second wellbore tubular122comprising the collet200may then be conveyed within the wellbore tubular120above the ball valve800. For example, the second wellbore tubular122may then be safely removed from the wellbore while the lower portion of the wellbore may be shut in via the closed ball valve800.

In this embodiment, the collet, including the surfaces of the collet protrusion, may be configured so that the first force applied to the actuation mechanism to actuate the ball valve800to an open position and pass the second wellbore tubular122through the ball valve800may be less than the second force applied to the actuation mechanism to actuate the ball valve800to a closed position. In an embodiment, the second wellbore tubular122may comprise coiled tubing, and the first force applied to the actuation mechanism to actuate the ball valve800to an open position may be less than the buckling limit (i.e., a compressive force threshold) of the coiled tubing. In this embodiment, the second force applied to the actuation mechanism to actuate the ball valve800to a closed position may be greater than the first force and below the tensile force limit of the coiled tubing.

The collet described herein may allow for the use of differential forces to be applied to actuate a downhole tool in different directions. The use of differential forces may allow for various wellbore tubulars to be used for actuating downhole tools that have a different tensile and compressive load limits, such as coiled tubing and the like. The ability to apply different forces in different directions may also be used to actuate downhole tools having differential opening and closing loads. Further, the collet described herein achieves the differential applied forces based on the configuration of the engagement surfaces of the collet protrusion being located at different points along the springs of the collet. While the angle of the engagement surfaces may alter the amount of longitudinal force and radial force applied to an actuation mechanism, this technique may only allow for a limited and unpredictable amount of force differential when the interference distance is small. The use of varying engagement points may advantageously produce a more predictable and consistent interaction between the collet and an actuation mechanism.