US20140166366A1

US20140166366A1 - Single-trip lateral coring systems and methods

Info

Publication number: US20140166366A1
Application number: US14/104,566
Authority: US
Inventors: Robert Utter; Shantanu N. Swadi; Praful C. Desai
Original assignee: Smith International Inc
Current assignee: Smith International Inc
Priority date: 2012-12-13
Filing date: 2013-12-12
Publication date: 2014-06-19
Also published as: GB2523503A; NO20150763A1; GB2523503B; WO2014093762A1; US20140166367A1; BR112015013716A2; GB201510059D0; AP2015008558A0; US9512680B2; NO340429B1

Abstract

A coring system may be used to create a lateral section or borehole off a wellbore, and obtain a core sample therefrom. The coring system may include a coring assembly connected to a deflector assembly to enable a single-trip coring operation. The coring assembly may include a coring bit and an outer barrel for extracting a core sample. A deflector of the deflector assembly may direct the coring bit to drill a lateral section in the borehole and extract a core sample therefrom. The coring assembly and deflector may include mating surfaces to collectively retrieve the deflector assembly and coring assembly in a single trip. A collar of the coring assembly may engage against a stop surface of a shoulder or sleeve of the deflector assembly. By pulling upwardly, the engaged collar may release the anchored deflector.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of, and priority to, U.S. patent application Ser. No. 61/736,982, filed on Dec. 13, 2013 and entitled “SINGLE-TRIP LATERAL CORING SYSTEMS AND METHODS,” which application is incorporated herein by this reference in its entirety.

BACKGROUND

In order to determine the properties of a particular formation, a core sample may be extracted. For instance, a vertical wellbore may be created in a formation. A column of rock or other materials found in the formation may be extracted as the wellbore is made, and then removed from the wellbore, after which a detailed study may be performed. The detailed study and analysis may yield information and identify the lithology of the formation. Other characteristics such as porosity and permeability of the formation, the potential storage capacity and/or production potential for hydrocarbon-based fluids (e.g., oil and natural gas), and the like may also be determined from the core sample.
Coring systems may attempt to extract the core sample in a state that, to the extent possible, closely resembles the natural state in which the rock and other materials are found in the formation. For instance, a coring bit may be connected to a drill string and extended into a wellbore. The coring bit may include a central opening and, as the coring bit rotates and drills deeper into the formation, materials from the wellbore can enter through the central opening and form a column of rock in the drill string. When the column has a desired length, the column of rock may be retrieved and brought to the surface.
The column of rock forming the core sample may form directly within the drill string, and then be returned to the surface by lifting the coring bit towards the surface. In other systems, a core barrel may be lowered through the central opening in the drill string. A column of rock can form in the core barrel, and the core barrel can be retrieved. Another core barrel may then be lowered through the drill string and used to obtain another core sample from the vertical section of the formation

SUMMARY OF THE DISCLOSURE

Assemblies, systems and methods of the present disclosure may relate to obtaining a core sample from a lateral section, or borehole, extending from a wellbore. In one example system, a coring system is provided to extract a core sample in a single trip. The example coring system may include a coring assembly that includes a coring bit attached to a core barrel. The core barrel may include a collection cavity where a core sample may be collected. The coring assembly may be connected to a deflector used to deflect the coring assembly as it drills a lateral section, ore borehole, and extracts the core sample. A releasable attachment between the coring assembly and the deflector may allow collective run-in of the coring assembly and deflector into a wellbore, and later separation to allow the coring assembly to drill the lateral section ore borehole and extract a coring sample.
In another implementation, a single-trip coring system may include a coring assembly having an outer core barrel coupled to a coring bit. A sacrificial element may connect the coring assembly to a deflector assembly with a ramp face. An anchor assembly may be coupled to the deflector assembly and may include expandable slips to engage a wall of the wellbore.
In another implementation, a method may be used to drill a lateral borehole and extract a core sample therefrom in a single trip. The method may include inserting a coring system into a wellbore within a formation, the coring system including a coring assembly coupled to a deflector assembly. The deflector assembly may be anchored within the wellbore and a coupling between the coring and deflector assemblies may be released. A lateral borehole may be drilled using the coring assembly. Drilling the lateral wellbore may result in simultaneously obtaining a core sample from the formation. The core sample and a portion of the coring assembly may then be removed from the borehole.
This summary is provided solely to introduce some features and concepts that are further developed in the detailed description. Other features and aspects of the present disclosure will become apparent to those persons having ordinary skill in the art through consideration of the ensuing description, the accompanying drawings, and the appended claims. This summary is therefore not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claims.

BRIEF DESCRIPTION OF DRAWINGS

In order to describe various features and concepts of the present disclosure, a more particular description of certain subject matter will be rendered by reference to specific embodiments which are illustrated in the appended drawings. Understanding that these drawings depict example embodiments and are not to be considered to be limiting in scope, nor drawn to scale for each embodiment contemplated herein, various embodiments will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:

FIG. 1 illustrates a partial cross-sectional view of an example system for extracting a core sample from a rock formation, according to one embodiment of the present disclosure;

FIG. 2 illustrates an enlarged view of a coring assembly of the system of FIG. 1, according to one embodiment of the present disclosure;

FIG. 3 illustrates another partial cross-sectional view of the system of FIG. 1, the system being used to extract a lateral core sample deviating from the primary wellbore, according to an embodiment of the present disclosure;

FIG. 4 illustrates a cross-sectional view of another coring system for extracting a lateral core sample, the coring system including a coring assembly and deflector assembly for one-trip setting of the deflector and extraction of the core sample;

FIGS. 5 and 6 illustrate the coring system of FIG. 4, with the coring assembly deflected laterally to extract the lateral core sample, according to one embodiment of the present disclosure;

FIG. 7 illustrates the coring system of FIG. 4, with the coring assembly retracted from a lateral section in accordance with an embodiment of the present disclosure;

FIG. 8 illustrates the coring system of FIG. 4, with the coring assembly and deflector assembly collectively being removed from the wellbore according to an embodiment of the present disclosure;

FIGS. 9-11 illustrate cross-sectional views of another example of a coring system, in various stages of a method that includes inserting a single-trip coring system, extracting a lateral core sample, and retrieving the coring system from the wellbore, in accordance with an example embodiment of the present disclosure;

FIG. 12 illustrates a cross-sectional view of an example anchor assembly that may be used in a coring system in accordance with some embodiments of the present disclosure;

FIG. 13 illustrates a cross-sectional end view of the anchor assembly of FIG. 12, taken along the plane 13-13 of FIG. 12; and

FIG. 14 illustrates an enlarged cross-sectional view of one embodiment of a locking subassembly of the anchor assembly of FIG. 12.

DETAILED DESCRIPTION

In accordance with some aspects of the present disclosure, embodiments herein relate to systems and assemblies for extracting a core sample from a formation. More particularly, embodiments disclosed herein may relate to systems, assemblies and methods for extracting a core sample from a lateral section, borehole, or other deviated portion of a wellbore. Further embodiments may also relate to extracting a core sample closely resembling the natural state of the formation, and of a size allowing for study and analysis, while minimizing or eliminating compaction, fracture, or other deformation of the core sample. More particularly still, embodiments disclosed herein may relate to single-trip systems and assemblies for anchoring a deflector, extracting a core sample from a lateral section, and retrieving the deflector and coring assembly.
Some principles and uses of the teachings of the present disclosure may be better understood with reference to the accompanying description, figures and examples. It is to be understood that the details set forth herein and in the figures are presented as examples, and are not intended to be construed as limitations to the disclosure. Furthermore, it is to be understood that the present disclosure and embodiments related thereto can be carried out or practiced in various ways and that aspects of the present disclosure can be implemented in embodiments other than the ones outlined in the description below.
To facilitate an understanding of various aspects of the embodiments of the present disclosure, reference will be made to various figures and illustrations. In referring to the figures, relational terms such as, but not exclusively including, “bottom,” “below,” “top,” “above,” “back,” “front,” “left,” “right,” “rear,” “forward,” “up,” “down,” “horizontal,” “vertical,” “clockwise,” “counterclockwise,” “inside,” “outside,” and the like, may be used to describe various components, including their operation and/or illustrated position relative to one or more other components. Relational terms do not indicate a particular orientation or position for each embodiment contemplated herein. For example, a component of an assembly that is “below” another component while within a wellbore may be at a lower elevation while in a vertical portion of a wellbore, but may have a different orientation during assembly, or when the assembly is in a lateral or deviated portion a the borehole, when outside of the borehole or wellbore, during manufacture, or at other times. Accordingly, relational descriptions are intended solely for convenience in facilitating reference to some embodiments described and illustrated herein, but such relational aspects may be reversed, rotated, moved in space, placed in a diagonal orientation or position, placed horizontally or vertically, or similarly modified.
Relational terms may also be used to differentiate between similar components; however, descriptions may also refer to certain components or elements using designations such as “first,” “second,” “third,” and the like. Such language is also provided for differentiation purposes, and is not intended limit a component to a singular designation. As such, a component referenced in a description of a particular embodiment as the “first” component may be the same component that may be referenced in the claims as a “second,” “third,” or other component. Furthermore, to the extent the description refers to “an additional” or “other” element, feature, aspect, component, or the like, it does not preclude there being one such element, feature, aspect, component, or the like in other embodiments. Where the claims or specification refer to “a” or “an” element, such reference is to be inclusive of other components and understood as “one or more” of the element. No component, feature, structure, or characteristic is to be considered as required or essential unless explicitly stated as such for each embodiment of the present disclosure.
Technical and scientific terms used herein are to have a meaning as understood by a person having ordinary skill in the art to which embodiments of the present disclosure belong, unless otherwise defined. Embodiments of the present disclosure can be implemented in the testing or practice with methods and materials equivalent or similar to those described herein.
Referring now to FIG. 1, an example coring system 100 is illustrated. The coring system 100 of FIG. 1 may be inserted within a wellbore 102 in a formation 104, and used to extract a core sample of the formation 104. In some embodiments, the core sample extracted from the formation may be core sample removed from a lateral or deviated perforation of the wellbore 102, rather than from a vertical portion of the wellbore 102.
In the particular embodiment illustrated in FIG. 1, the coring system 100 is shown as including a coring assembly 106, a deflector assembly 108, and an anchor assembly 110, each of which are optionally interconnected. As discussed in greater detail herein, for instance, the coring assembly 106 may be connected to the deflector assembly 108, and the coring assembly 106, deflector assembly 108, and anchor assembly 110 may collectively be inserted and run into the wellbore 102, and lowered to a desired position. When at the desired location, the anchor assembly 110 may be secured in place. For instance, in this embodiment, the anchor assembly 110 includes an anchor 112 and expandable slips 114 that may engage the inner surface of the wellbore 102, although the anchor assembly 110 may include any suitable construction, and may be integral with, or distinct from, the deflector assembly 108. A frictional or other engagement between the expandable slips 114 and the inner surface of the wellbore 102 may effectively hold the anchor 112 and the deflector assembly 108 at a desired axial position, and potentially at a desired orientation, within the wellbore 102.
The coring assembly 106 may be separable from the deflector assembly 108 in an embodiment in which the coring assembly 106 is connected to the deflector assembly 108 and/or the anchor assembly 110. By way of illustration, a selectively engageable latch or other mechanism may be used to selectively connect and/or disconnect the coring assembly 106 relative to a deflector 116 of the deflector assembly 108. In other embodiments, and as described in greater detail hereafter, a sacrificial element may be used to connect the coring assembly 106 to the deflector assembly 108. For instance, once the anchor assembly 110 is secured at an axial and/or rotational position within the wellbore 102, axial and/or rotational movement of the coring assembly 106 may be used to break a sacrificial element, thereby disconnecting the coring assembly 106 from the deflector 116.
While the coring assembly 106, deflector assembly 108, and anchor assembly 110 may be collectively run into the wellbore 102 to allow a single trip to insert, anchor, and use such assemblies, such an embodiment is merely illustrative. In other embodiments, for instance, the coring assembly 106 may be separate from the deflector assembly 108. In such an embodiment, the anchor assembly 110 may be anchored in place. Thereafter, the coring assembly 106 may be run into the wellbore 102. Of course, the deflector assembly 108 may be run into the wellbore 102 and secured in a desired position and orientation collectively with the anchor assembly 110, or run in and secured in place following insertion and/or anchoring of the anchor assembly 110.
Regardless of whether the coring assembly 106 is connected to the anchor assembly 110 and/or deflector assembly 108 to allow for single-trip extraction of a core sample, the coring assembly 106 may use the deflector assembly 108 to extract a core sample from the wellbore 102, and potentially a deviated or lateral section of the wellbore 102 as discussed hereafter. For instance, as shown in FIG. 1 and as better viewed in the enlarged view of FIG. 2, the coring assembly 106 may include a coring bit 118 for drilling into the formation 104 and extracting a core sample therefrom. The coring bit 118 may be connected to an outer barrel 120 (e.g., using threaded connector 122), and core samples may collect within the coring bit 118 and/or the outer barrel 120.
In particular, the coring bit 118 may include an opening 124 in a distal end thereof, which opening 124 may be in communication with a collection chamber 126 within the coring bit 118 and/or the outer barrel 120. The coring bit 118 and the outer barrel 120 may be connected to a drill rig (not shown) that can rotate the coring bit 118, optionally by also rotating the outer barrel 120 and/or a drill string (not shown) attached to the outer barrel 120. As one or more cutters 128 on the coring bit 118 cut into the formation 104, materials from the formation may collect within the collection chamber 126 to form a columnar core sample. When the coring bit 118 has cut deep enough to fill the collection chamber 126, or otherwise obtain a sample for study, the core sample can be removed. To remove the core sample, the entire coring assembly 106 could be withdrawn from the wellbore 102.
In another embodiment, however, a core sample may be obtained and removed without corresponding removal of the coring assembly 106. For instance, in this particular embodiment, an inner barrel 130 may be located within the collection chamber 126. The inner barrel 130 may be selectively removable and can include an interior opening which may also act as a collection chamber. As shown in FIGS. 1 and 2, for instance, a retrieval wire 132 may be connected to an upper end of the inner barrel 130. When the core sample is desired, the inner barrel 130 may be lowered into the coring assembly 106. The core barrel 130 may be located at any desired position, including adjacent the distal end of the coring bit 118. As the coring bit 118 then drills the wellbore 102, or cuts a lateral section into the wellbore 102, the core sample may collect inside the collection chamber of the inner barrel 130. When the inner barrel 130 is filled or otherwise has a core sample of a desired size, an operator may use the retrieval wire 132 to remove the inner barrel 130 and extract the core sample. If additional core samples are desired, the inner barrel 130 (or a different inner barrel 130) may be lowered towards the coring bit 118, and drilling may continue until another core sample is obtained.
A core sample collected within the collection chamber 126 of the outer barrel 120 or the inner barrel 130 may have any suitable size and shape. For instance, as discussed herein, a length of the collected core sample may vary from a few inches to many hundreds of feet. The width of the core sample may also vary. For instance, the opening 124 and collection chamber 126 (or the interior of the inner barrel 130) may have a width from about one inch (25 mm) to about four inches (102 mm). In a more particular embodiment, the inner barrel 130 and/or outer barrel 120 may collect a core sample having a width greater than two inches (51 mm), which can facilitate measuring porosity of the formation 104. Of course, in other embodiments, the core sample may have a width or diameter less than one inch (25 mm) or greater than four inches (102 mm). Moreover, while the core sample may have a circular cross-sectional shape in some embodiments, the outer barrel 120 and/or inner barrel 130 may in other embodiments facilitate collection of a columnar core sample having a square, elliptical, trapezoidal, or other cross-sectional shape.
The coring assembly 106 may include any number of additional or other components. For instance, the inner barrel 130 and collection chamber 126 may be illustrated in FIGS. 1 and 2 somewhat schematically. In some embodiments, the inner barrel 130 and/or collection chamber 126 may include fasteners to secure the inner barrel 130 in place within the outer barrel 120 and/or the coring bit 118. Such fasteners may be selectively engageable and disengageable to allow removal of the inner barrel 130 independent of the outer barrel 120 or the coring assembly 106.
As also seen in FIG. 2, an example coring assembly 106 may also include one or more hydraulic lines 134, 136. In this particular embodiment, fluid may be pumped through a channel 138 in the outer barrel 120, and directed towards the coring bit 118. The channel 138 of this embodiment is shown as surrounding the collection chamber 126; however, in other embodiments the channel 138 may be otherwise located or omitted entirely. As fluid is sent through the channel 138, it may pass into one or more hydraulic lines 134 within the coring bit 118 or outer barrel 120. Such fluid may then be used as a cutting fluid to facilitate cutting by the coring bit 118.
In another embodiment, fluid passing through the hydraulic line 134 and/or the channel 138 may be used for additional or other purposes. For instance, the embodiment shown in FIG. 2 illustrates an additional hydraulic line 136 outside of the coring bit 118. The illustrated hydraulic line 136 is shown as extending to the deflector 116, but may extend to any desired location, and can be used for any suitable purposes. For instance, referring again to FIG. 1, the coring assembly 106 may be connected directly or indirectly to an anchor assembly 110, and one or more expandable slips 114 may be selectively expanded or retracted using hydraulic fluid supplied by the hydraulic line 134. When expanded, the expandable slips 114 may engage the wellbore 102 and anchor the deflector 116 in place. Thereafter, the coring assembly 106 may be inserted into the wellbore 102, or detached from the deflector 116, to begin a coring process.
More particularly, as noted above, some embodiments of the present disclosure relate to using the coring assembly 106 to extract a core sample from a lateral section or perforation of the wellbore 102. Turning now to FIG. 3, the example coring system 100 of FIG. 1 is shown in additional detail, while extracting a lateral core sample.
In general, the deflector 116 may be used to deflect the coring assembly 106 laterally to create a deviated or lateral section 103 in the wellbore 102. As the deflection occurs, the coring assembly 106 may drill laterally into the formation 104 and extract a core sample from the lateral section 103 of the wellbore 102, as opposed to a vertical or other primary section of the wellbore 102. In FIGS. 1 and 3 for instance, the deflector 116 is shown as being generally wedge-shaped, and having a ramp face 140. The particular incline of the ramp face 140 may be varied in any number of manners. For instance, relative to the longitudinal axis of the vertical portion of the wellbore 102, the ramp face 140 may extend at an angle between about 1° and about 10°, although such an embodiment is merely illustrative. In a more particular embodiment, the angle may be between about 2° and about 6°. In still another example embodiment, the angle of the ramp face 140 may be about 3°. Of course, in other embodiments, the ramp face 140 may be inclined at an angle less than about 1° or more than about 10°.
Further, while the ramp face 140 may have a single segment extending at a constant incline, in other embodiments the ramp face 140 may have multiple segments. In this particular embodiment, for instance, the ramp face 140 is shown as including at least two segments, each with a different degree of incline. In other embodiments, however, the ramp face 140 may include three or more segments, any or each of which may have a different incline relative to other segments.
As the coring assembly 106 is detached from the deflector 116, or when inserted into the borehole following anchoring of the anchor assembly 110 and the deflector assembly 108, the coring bit 118 may come into contact with the ramp face 140. Because of the angle on the ramp face 140, further downward movement of the coring assembly 106 may cause the coring bit 118 to travel across the ramp face 140, and gradually move towards the sidewall of the wellbore 102. The coring bit 118 may optionally rotate as it moves along the ramp face 140 and/or as it engages the sidewall of the wellbore 102. Using cutting elements, the coring bit 118 may then cut laterally into the wellbore 102 and form the lateral section 103.
As discussed herein, when the coring bit 118 forms the lateral section 103 of the borehole, rock and other materials of the formation 104 may pass through an opening 124 in the coring bit 118 and collect within the collection chamber 126 and/or an inner barrel 130. Ultimately, once a core sample of a desired size has been collected (e.g., when the inner barrel 130 is filled or near filled), the core sample may be extracted. Extraction of the core sample may occur with or without removal of the coring assembly 106, as discussed herein.
One aspect of a coring system 100 of the present disclosure may therefore include the ability to extract a core sample from a deviated portion of a borehole, with such sample having any desired length. Indeed, in some embodiments, a core sample extracted using the coring system 100 may extend many hundreds of feet (e.g., 1000 feet, 2000 feet, or more) into the lateral section 103 of the wellbore 102. In other embodiments however, the core sample may be much shorter (e.g., less than 1000 feet in some embodiments, less than 100 feet in other embodiments, and less than 50 feet in still other embodiments). As an example, if an operator of the coring system 100 wishes to obtain a sample of the formation three feet (0.9 m) away from the wellbore 102, as measured in a direction perpendicular to the wellbore 102, and the lateral section 103 extends at a constant angle of 3° relative to the longitudinal axis of the wellbore 102, a core sample of about sixty feet (18.3 m) should provide the desired information. Of course, if angle of the lateral section 103 is greater or smaller than 3°, or varies along its length, or if the desired information is nearer or further from the primary portion of the wellbore 102, the length of the core sample may vary. Further, while the illustrated wellbore 102 is shown as vertical, a wellbore may not be vertical; however, the coring system 100 may be used to drill a lateral, deviated section, or borehole, off of even a non-vertical wellbore to obtain a core sample.
While some formations may have relatively constant properties over large distances, other formations may show large deviations over even short distances. Accordingly, by extending the coring assembly 106 laterally from the primary portion of the wellbore 102, a core sample may therefore be obtained to capture formation properties further from the main wellbore 102. Gradients and other changes in properties may therefore be analyzed and determined. Further, because core samples may be of virtually any continuous length, core samples may be relatively unfractured and large enough to allow for simplified analysis. Further still, as continuous core samples are obtained through a coring bit 118, the coring system 100 may operate with few or no explosives that could otherwise create fractured or compacted core samples.
While a core sample may be obtained over a lateral section 103 that extends a relatively short distance from the primary portion of the wellbore 102, the length may be much larger as noted above. Indeed, the lateral section 103 may extend for potentially hundreds of feet as discussed herein. Optionally, to facilitate lateral drilling of the lateral section 103, the coring assembly 106 may use directional drilling equipment. While not shown in FIGS. 1-3, such directional drilling equipment may include steerable drilling assemblies that include a bent angle housing to direct the angle of drilling during drilling of the lateral section 103. The directional drilling equipment may employ other directional control systems including, but not limited to, rotary steerable systems. Example rotary steerable systems may include hydraulically controlled pads, deflecting rods, or a variety of other features and components used to push, point, or otherwise control a drilling direction.
As discussed above, some aspects of the present disclosure further relate to a coring system that allows a core sample to be taken in a deviated portion of a borehole, while also using a single trip to anchor the deflection assembly and obtain the core sample. Some systems may also allow detachment and retrieval of the deflection assembly in the same, single trip. Turning now to FIGS. 4-8, an example single-trip coring system 200 is illustrated in greater detail. In particular FIGS. 4-8 illustrate various steps in an example method that may be used to run the coring system in a wellbore 202, drill a lateral section of a wellbore 202, obtain a core sample, and remove the coring assembly and/or deflector assembly. The single-trip coring system 200 may share various features with the coring system 100 of FIGS. 1-3. To avoid obscuring aspects of the embodiment in FIGS. 4-8, redundant features may not be described again in detail, but it should be appreciated by a person having ordinary skill in the art that the various features of FIGS. 1-3 (e.g., an anchor assembly having expandable slips, an inner barrel, hydraulic lines and channels, etc.) may be incorporated into the embodiments of FIGS. 4-8.
More particularly, FIG. 4 illustrates a single-trip coring system 200 that may include a coring assembly 206 connected to a deflector assembly 208 in accordance with some embodiments of the present disclosure. In this particular embodiment, the coring assembly 206 and deflector assembly 208 may be connected in a manner that allows the coring assembly 206 to be run into the wellbore 202 at the same time as the deflector assembly 208.
The coring assembly 206 and deflector assembly 208 may be placed in the wellbore 202, and lowered to a desired location. The deflector assembly 208 may include a deflector 216 with a ramp face 240. When the ramp face 240 is oriented in a direction corresponding to a desired trajectory for a lateral section of the wellbore 202, the deflector assembly 208 can be anchored in place. Following anchoring of the deflector assembly 208, the coring assembly 206 can be separated from the deflector assembly 208 and moved along the length of the ramp face 240 to create the lateral section or borehole off the wellbore 202, and to take a core sample.
In the particular embodiment shown in FIG. 4, a sacrificial element 242 may connect the coring assembly 206 to the deflector assembly 208. The illustrated sacrificial element 242 may extend between the deflector 216 and a shaft of the coring bit 218 and/or outer barrel 220, but may have any suitable configuration. In operation, the sacrificial element 242 may be designed to break or fail when a sufficient load is placed thereon. For instance, once the deflector 216 is anchored in place, an axial load may be placed on the outer barrel 220 of the coring assembly 206 (e.g., by loading a drill string). The anchored deflector 216 may be configured to have a higher resistance to an axial load that the sacrificial element 242, such that when the load exceeds the maximum force allowed by the sacrificial element 242, the sacrificial element 242 may break but the deflector 216 may remain anchored in place.
In another embodiment, the coring assembly 206 may rotate to break the sacrificial element 242. By way of illustration, the coring bit 218 and/or outer barrel 220 of the coring assembly 206 may be configured to rotate to drill a lateral section of the wellbore 202. In this embodiment, the coring bit 218 may be integrated with the outer barrel 220, and the sacrificial element 242 may break when the rotational force is applied to the outer barrel 220 (e.g., by a surface rig). Regardless of whether the sacrificial element 242 breaks as a result of axial loading, rotation of the coring assembly 206, or in some other manner, the coring assembly 206 may break free from the deflector assembly 208 and be allowed to move axially along the wellbore 202.
The sacrificial element 242 may take any number of different forms. In FIG. 4, for instance, the sacrificial element 242 may be a shear screw or break bolt configured to fail when a load is applied to translate or rotate the coring assembly 206 relative to the deflector assembly 208 (e.g., when the deflector assembly 208 is anchored). In other embodiments, the sacrificial element 242 may include a notched tab configured to break where stress concentrations form at notches. In still other embodiments, other sacrificial elements or non-sacrificial elements may be used. Thus, the sacrificial element 242 may be replaced by other structures, such as a selectively engageable latch that allows selective disconnection and/or reattachment of the coring assembly 206 relative to the deflector assembly 208, without breaking a connector.
Once the sacrificial element 242 is broken, an operator of the coring system 200 may move the coring assembly 206 downwardly, further into the wellbore 202. Upon doing so, the coring assembly 206 may move along a ramp face 240 of the deflector system 208, and can be directed against the interior surface of the wellbore 202. The coring bit 218 can rotate or otherwise be used to cut into the formation 204 and create a lateral section of the wellbore 202. As shown in FIGS. 5 and 6, the coring bit 218 may progressively cut a lateral section 203 that deviates laterally relative to a primary or other portion of the wellbore 202.
As the coring bit 218 cuts into the formation 204 and forms the lateral section 203 of the wellbore 202, the coring bit 218 may extract samples of the formation 204. In this particular embodiment, the coring bit 218 and the outer barrel 220 of the coring assembly 206 define a collection chamber 226 that is accessible through an opening 224 in the distal end of the coring bit 218. A core sample may therefore collect in the collection chamber 226 for removal either with the coring assembly 206, or independent from removal of the coring assembly 206 (e.g., using an inner barrel). Multiple core samples may also be obtained without removing the coring assembly 206 as discussed in greater detail with respect to FIGS. 1-3. Both the outer barrel 220 and an inner barrel may be examples of core barrels usable in connection with coring systems of the present disclosure.
When the desired core samples have been obtained, an operator of the coring system 200 may remove the coring assembly 206. As shown in FIG. 7, for instance, the coring assembly 206 may be removed from the lateral section 203 of the wellbore 202 by pulling upwardly on the outer barrel 220 and the coring bit 218.
In the embodiment shown in FIGS. 4-7, removal of the coring assembly 206 may also be used to remove the deflector assembly 208. For instance, as shown in FIG. 7, the coring bit 218 and/or outer barrel 220 may include, or be connected to, a collar 244 that extends radially outward from the outer barrel 220. The deflector assembly 202 may, in turn, include or be attached to a sleeve 246. In the illustrated embodiment, the sleeve 246 of the deflector assembly 208 is shown as defining an opening or passageway through which the outer barrel 220 of the coring assembly 216 may pass. The size of the opening may be such that the inner diameter of the opening allows the outer diameter of the outer barrel 220 to be slideably received thereby. The inner diameter of the opening may, however, be smaller than the outer diameter of the collar 244. As a result, when the coring assembly 206 is pulled back, the collar 244 may engage the lower surface 248 of the sleeve 246, which lower surface 248 may act as a stop surface by restricting the collar 244 from moving upwardly past the lower surface 248. To move the coring assembly 206 upwardly, the deflector assembly 208 may therefore also be un-anchored and released from engagement with the wellbore 202. In embodiments in which the deflector assembly 208 is anchored in place, the deflector assembly 208 may be released in any number of manners. A more particular discussion of one manner for releasing the anchored deflector assembly 208 is discussed in additional detail with respect to FIGS. 12-14. FIG. 8 illustrates the coring assembly 206 moving upwardly and carrying the deflector assembly 208, as the anchored position of the deflector assembly 208 is illustrated in phantom lines.
The sleeve 246 of the deflector assembly 208, and the collar 244 of the coring assembly 206, may be formed or constructed in any number of manners. For instance, the sleeve 246 may be integrally formed with the deflector 216. In another embodiment, such as that shown in FIGS. 4-8, the sleeve 246 may be mechanically fastened to the deflector 216. In this particular embodiment, a fastener 250 (e.g., a bolt, screw, pin, rivet, or other mechanical fastener, or some combination thereof) may be used to secure the sleeve 246 within a recess 252 in the deflector 216. When secured in place, the sleeve 246 is optionally secured to restrict, and potentially prevent, axial and/or rotational movement of the sleeve 246 along the wellbore 202. Thus, while the coring assembly 206 may move axially and/or rotationally within the wellbore 202, the sleeve 246 may remain static. In a similar manner, the collar 244 may be integrally formed, or distinct from, the coring bit 218 and/or the outer sleeve 220. Optionally, the collar 244 may rotate with the drill bit 218, although in other embodiments, the collar 244 may include a bearing or other component to allow rotation of the coring bit 218 independent of the collar 244.
In embodiments in which the sleeve 246 is static and the coring assembly 206 passes through the sleeve 246, the sleeve 246 may also be a bearing, or may include one or more bearings or bearing surfaces. For instance, the sleeve 246 may include one or more bearings or bushings to reduce friction as the coring assembly 206 moves axially within the opening in the sleeve 246 or to reduce friction as a result of the coring assembly 206 rotating within the opening in the sleeve 246. An example bearing that may be included as part of the sleeve 246, or connected thereto, may include a thrust bearing, roller bearing, spherical bearing, or other bearing, or some combination thereof. In an example embodiment using a spherical bearing, the bearing may allow angular deflection of the outer barrel 220 while the outer barrel 220 and coring bit 218 travel along the ramp face 240 of the deflector assembly 208 to drill a lateral section into the wellbore 202. A spherical bearing may also be used to support axial, sliding motion of the outer barrel 220 as coring assembly 206 moves in an upwardly or downwardly directed path.
The fastener 250 used to connect the sleeve 246 to the deflector 216 may also have additional or other properties or structures. For instance, rather than a mechanical fastener, the sleeve 246 may be secured in place using other mechanisms, including mechanical attachments such as welding, adhesives, thermal bonding, threaded connectors, and the like. Regardless of the particular type of attachment used to connect the sleeve 246 to the deflector 216, the attachment may have a greater structural strength when compared to the sacrificial element 242. In one embodiment, a greater structural strength of the fastener 250 or other mechanical attachment may be used to allow the sacrificial element 242 to break prior to failure of the fastener 250, to ensure that the coring assembly 206 can break free of the deflector 216, and remain guided by the fixed sleeve 246.
Another aspect of the present disclosure, as shown in FIGS. 7 and 8, includes for extracting a core sample by creating a lateral section 203 of the wellbore 202, while not creating a separate bore. When two bores are present, governmental regulations may provide for abandonment procedures to be performed separately on each bore, thereby increasing the cost and decreasing the efficiency in abandoning a well. However, a separate bore is not created, but rather the bore is merely widened, a single abandonment procedure may be performed. In particular, in comparing FIGS. 7 and 8, while a lateral section 203 may be created, the lateral section 203 may act as a perforation of the primary portion of the wellbore 202. Rocks or other materials of the formation 204 may be positioned between the lateral section 203 or borehole and the primary wellbore (see FIG. 7), but may wash out to connect the distal end of the lateral section 203 with the primary portion of the wellbore 202 (see FIG. 8). Washing out the lateral section 203 may be particularly likely when the length of the lateral section 203, or the maximum lateral offset from the vertical portion of the wellbore 202, is relatively short. Removing the coring assembly 206 in such embodiments may also facilitate wash outs such that the lateral section 203 or borehole may merely be a widened portion of the wellbore 202, rather than a separate bore or well. A wash out may also be particularly likely when the wellbore 202 is an uncased or openhole wellbore as shown in FIGS. 4-8, although in other embodiments a cased wellbore may be used.
Turning now to FIGS. 9-11, another embodiment of a coring system 300 is shown in additional detail. In particular, FIGS. 9-11 illustrate various elements of a method for anchoring a deflection assembly 308 and extracting a core sample in a single trip. Retrieval of the deflection assembly 308 may also include release of the deflection assembly 308 in some embodiments.
In general, the coring system 300 of FIGS. 9-11 may be relatively similar to the coring system 200 of FIGS. 4-8. For instance, the coring system 300 may include a coring assembly 306 that is connected to the deflection assembly 308 using a sacrificial element 342 or some other releasable connector. When inserting the coring assembly 306 and the deflection assembly 308 into the wellbore 302 formed in the formation 304, the sacrificial element 342 may be in an engaged or unbroken state that maintains the relative position of the coring assembly 306 relative to the deflection assembly 308. By selectively disengaging a releasable connector, or by causing the sacrificial element 342 to fail (e.g., using axial motion following anchoring of the deflector assembly 308, or by rotating a coring bit 318 of the coring assembly 306), the coring assembly 306 may move axially along the wellbore 302 while the deflector 316 remains anchored in place.
In the particular embodiment shown in FIGS. 9-11, the coring assembly 306 may include a coring bit 318 that can be mechanically attached to an outer barrel 320. In particular, this embodiment illustrates a threaded connector 322 between the coring bit 318 and the outer barrel 320. Using the threaded connector 322, the coring bit 318 may be selectively attached, removed, replaced, and the like. In other embodiments, the coring it 318 may be integrally formed with the outer barrel 320, or may be attached to the outer barrel 320 or a drill string (not shown) in other manners.
In general, the coring bit 318 may act in a manner similar to other coring bits described herein. In FIG. 9, for instance, the coring bit 318 is shown as including an opening 324 in the distal end thereof, and which facilitates the collection of a core sample. For instance, as the coring bit 318 drills laterally into the formation 304 (see FIG. 10), materials from the formation 304 may enter the opening 324 and collect within a collection chamber. An optional inner barrel (not shown) may also be provided to allow extraction of core samples without removal of the coring assembly 306, and/or collection of multiple, different core samples in a single trip of the coring assembly 306, whether collected along a single lateral section 303 or at multiple lateral sections.
In FIG. 9, the illustrated coring assembly 306 is shown as including a collar 344 connected to the coring bit 318 and/or the outer barrel 320. In particular, the illustrated collar 344 may include an interior opening into which the outer diameter of an upper portion of the coring bit 318 may be positioned. Optionally, the collar 344 has a fixed axial position along the coring assembly 306. Thus, once the coring assembly 306 is detached from the deflector assembly 308, the collar 344 may move along the deflector 316 along with the coring bit 318. While the illustrated embodiment illustrates the collar 344 positioned around the coring bit 318, in other embodiments the collar 344 may be secured to, or may encompass, a portion of the outer barrel 320.
The collar 344 may be used to guide the coring bit 318 in accordance with some embodiments of the present disclosure. In this particular embodiment, for instance, the deflector 316 of the deflector assembly 308 may include a track 340 for interfacing with the collar 344. The shape, size, and configuration of the track 340 may match that of the collar 344. For instance, the track 340 may have a concave surface with a contour to match an outer contour of the collar 344. In another embodiment, the track 340 may include a rail, guide, or other similar component that may correspond to the collar 344 and/or facilitate movement of the collar 344 along the track 340.
As the collar 344 moves downwardly and laterally along the track 340, the coring bit 318 may also move. The track 340 may be inclined relative to the longitudinal axis of the wellbore 302, thereby causing the coring bit 318 to ultimately engage a sidewall of the wellbore 302. By rotating the coring bit 318, the coring bit 318 can also cut into the sidewall at a trajectory corresponding to the configuration of the track 340. As shown in FIG. 10, for instance, the track 340 may guide the coring bit 318 as it creates a lateral section 303 of the wellbore 302. Of course, as the lateral section 303 is created, a core sample of the lateral section of the formation 304 may also be formed within the collection chamber 326 of the coring assembly 306.
Once the desired core samples are obtained, the coring assembly 306 may be removed as shown in FIG. 11. In particular, the outer barrel 320 may be connected to a drill string, and can be pulled upwardly. As the outer barrel 320 is pulled upwardly, the coring bit 318 may move out of the lateral section 303 of the wellbore 302, and towards an upper portion of the deflector assembly 308. In this particular embodiment, the upper portion of the deflector assembly defines a shoulder 346. More particularly, the coring bit 318 and the collar 344 may follow the track 340. The track 340 may direct the collar 344 of the coring assembly 306 against the shoulder 346, which can act as a stop surface to restrict the collar 344 from moving upwardly past the shoulder 346. The shoulder 346 may be sized so that the distance between the shoulder 246 and the sidewall of the wellbore 302 defines a passageway with sufficient size to allow the outer barrel 326 to slideably move therebetween. The collar 344 may, however, have an increased radial size, and may not fit in the passageway between the shoulder 346 and the sidewall of the wellbore 302. As a result, the collar 344 may engage the shoulder 346, which can restrict, and potentially prevent, the collar 344 from moving past the shoulder 346.
When pulling upwardly on the outer barrel 326, the coring assembly 306 may be used to retrieve the deflector assembly 308 from the wellbore 302. For instance, as discussed herein, the deflector assembly 308 may be selectively released from its anchored position within the wellbore 302. Following un-anchoring of the deflector assembly 308 (e.g., by releasing an anchor assembly connected to the deflector assembly 308), an upwardly-directed force on the coring assembly 306 may also cause the deflector assembly 308 to move upwardly by virtue of the engagement between the collar 344 and the shoulder 346.
The collar 344 of the embodiment shown in FIGS. 9-11 may have a number of different constructions. In one embodiment, for instance, the collar 344 may be integrally formed with the coring bit 318 and/or outer barrel 320, and may rotate with the coring bit 318 when it rotates and digs the lateral section 303 of the wellbore 302. In the illustrated embodiment, however, the collar 344 may also be separately formed and then attached to the coring assembly 306. The interior opening of the collar 344 may have a size sufficient to allow the coring bit 318 to be positioned therein. Optionally, the coring bit 318 may float within the collar 344. For instance, the collar 344 may be configured not to rotate with the coring bit 318. One or more bearings or other components may be used to facilitate rotation of the coring bit 318 within the collar 344. In one embodiment, the collar 344 includes a groove, notch or other structure that mates with a corresponding structure of the track 340. As a result, as the coring assembly 306 moves along the track 340, the drill bit 318 may rotate while the track 340 may restrict rotation of the collar 344.
As should be appreciated by a person having ordinary skill in the art in view of the disclosure herein, some embodiments of the present disclosure may relate to apparatus, systems, and methods for anchoring a deflector and extracting a core sample in a single trip. In accordance with some of those embodiments, the deflector may also be anchored and thereafter un-anchored to allow setting and retrieval in the same, single trip.
An example anchor assembly 410 that may be used in connection with embodiments of the present disclosure is shown in additional detail in FIGS. 12-14. This particular anchor assembly includes an anchor body 412 and one or more expandable slips 414. More particularly, as described in greater detail below, hydraulic fluid passing through the anchor body 412 may be used to selectively expand the expandable slips 414, which may then engage the exterior wall around a wellbore.
FIGS. 12-14 depict the example embodiment of an anchor assembly 410, with various operational positions. In one embodiment, the anchor assembly 410 may be used, for example, in combination with a coring assembly and a deflector assembly for extracting a core sample from a lateral section, or borehole of a wellbore, or from some other lateral section or borehole (e.g., a deviation portion from an already deviated borehole). It should be appreciated, however, that the anchor assembly 410 may be used in many different types of downhole assemblies, and that coring assemblies and/or deflector assemblies are not exhaustive representations of the assemblies or components with which the anchor assembly 410 may be used. For instance, the anchor assembly 410 may be used in any drilling assembly using an anchoring tool, including with a whipstock for a sidetracking process. Further, it is to be fully recognized that the different teachings of the embodiments disclosed herein may be employed separately or in any suitable combination to produce desired results.
FIGS. 12-14 provide an operational overview of the anchor assembly 410. In particular, the anchor assembly 410 may be lowered into an uncased wellbore in a locked and collapsed position shown in FIGS. 12 and 13. When the anchor assembly 410 reaches a desired depth, the anchor assembly 410 may be unlocked and expanded to a set position shown in phantom lines in FIGS. 12 and 13, where expandable slips 414 of the anchor assembly 410 may engage a surrounding open wellbore wall, or a casing. The anchor assembly 410 may be configured to expand over a range of diameters, and FIGS. 12 and 13 depict the anchor assembly 410, with the maximum expanded configuration shown in phantom lines. Finally, to remove the anchor assembly 410 from the well, the anchor assembly 410 may be released from the casing to return to an unlocked and collapsed position as shown in FIG. 12.
The anchor assembly 410 may generally comprise a top sub 454 connected via threads 456 to a generally cylindrical mandrel 457 having a fluid channel 466 therethrough, which in turn is connected via threads 456 to a nose 458. In one embodiment, the anchor assembly 410 may include an upper box connection 460 and a lower pin connection 462 for connecting the anchor assembly 410 into a downhole assembly. The upper box connection 460 may be connected to the lower end of a deflector assembly 408, for example. Optionally, a pipe plug 464 may be connected to the nose 458 to close off a fluid channel 466 of the mandrel 457 so that the anchor assembly 410 may be expanded hydraulically.
The mandrel 457 may be the innermost component within the anchor assembly 410. Disposed around and slidingly engaging the mandrel 457 is a spring stack 468 in the illustrated embodiment, along with an upper slip housing 470, one or more slips 414, and lower slip housing 472. One or more recesses 474 may be formed in the slip housings 470, 472 to accommodate the radial movement of the one or more slips 414. The recesses 474 may include angled channels formed into the wall thereof, and these channels may provide a drive mechanism for the slips 414 to move radially outwardly into the expanded positions depicted in phantom lines in FIGS. 12 and 13. In one embodiment, the anchor assembly 410 may comprise three slips 414 as shown in FIG. 13, wherein the three slips 414 may be spaced at 120° intervals circumferentially around the anchor assembly 410, and in the same radial plane. It should be appreciated, however, that any number of slips 414 may be disposed in the same radial plane around the anchor assembly 410. For example, the anchor assembly 410 may comprise four slips 414, each approximately 90° from each other, two slips 414, each approximately 180° from each other, or any number of slips 414. Further, while the slips 414 may be offset at equal angular intervals, other embodiments contemplate such offsets being varied. For instance, when three slips 414 are used, the one slip 414 may be spaced about 90° from one slip 414 and about 135° from another slip 414.
In the embodiment shown in FIG. 12, a piston housing 476 may be connected to the lower slip housing 472 (e.g., using threads). The piston housing 476 may form a fluid chamber 478 around the mandrel 457 within which a piston 480 and a locking subassembly 482 may be disposed. The piston 480 may connect to the mandrel 457 (e.g., using threads), and the mandrel 457 may include ports 484 that enable fluid flow from the flowbore 466 into the fluid chamber 478 to actuate the anchor assembly 410 to the expanded position shown in phantom lines in FIGS. 12 and 13. In one embodiment, a seal may be provided between the piston 480 and the mandrel 457, between the piston 480 and the piston housing 476, and/or between the piston housing 476 and the lower slip housing 472.
FIG. 14 depicts an enlarged view of the locking subassembly 482, shown releasably coupled to the piston housing 476 via one or more shear screws 486. The locking subassembly 482 shown in FIG. 14 may include a lock housing 488 mounted about the mandrel 457, and a lock nut 490, which interacts with the mandrel 457 to prevent release of the anchor assembly 410 when pressure is released. The outer radial surface of mandrel 457 may include serrations which cooperate with inverse serrations formed on the inner surface of locking nut 490, as described in more detail below.
Referring now to FIGS. 12 and 13, the anchor assembly 410 is illustrated with the slips 414 in a retracted position which allows the anchor assembly 410 to be inserted into a wellbore. When the slips 414 are expanded to the position illustrated in phantom lines in FIGS. 12 and 13, the slips 414 may be in an expanded position, in which the slips 414 extend radially outwardly into gripping engagement with a surrounding open wellbore wall or casing. The anchor assembly 410 may have two operational positions within a particular wellbore—namely a collapsed position as shown in FIGS. 12 and 13 for running the anchor into a wellbore, and an expanded position as shown in phantom lines in FIGS. 12 and 13, for grippingly engaging a wellbore.
To actuate the anchor assembly 410, hydraulic forces may be applied to cause the slips 414 to expand radially outwardly from the locked and collapsed position of FIGS. 12 and 13 to the unlocked and expanded position shown in phantom lines. Specifically, fluid may flow down the fluid channel 466 and through the ports 484 in the mandrel 457 into the chamber 478 surrounded by the piston housing 476. When the anchor assembly 410 is the lowermost tool in a drilling, coring, or other system, the pipe plug 464 may be used to close off the fluid channel 466 through the mandrel 457 to allow fluid pressure to build up within the anchor assembly 410 to actuate it (e.g., by radially expanding the slips 414 of the anchor assembly 410). If, however, another tool is run below the anchor assembly 410, the pipe plug 464 may be removed so that hydraulic fluid can flow through the anchor assembly 410 to the lower tool. In such an operation, the lower tool could include a similar pipe plug so that hydraulic pressure can be built up in both the lower tool and the anchor assembly 410 to actuate both tools.
Pressure may continue to build in the fluid chamber 478 as the piston 480 provides a seal therein until the pressure is sufficient to cause shear screws 492 to shear. Since the piston 480 may be connected to the mandrel 457, the piston 480 may remain stationary while the outer piston housing 476 and the lower slip housing 472 connected thereto may move axially upwardly from the position shown in FIG. 12. Upward movement of the lower slip housing 472 can act against the slips 414 to drive the slips 414 radially outwardly along the channels 494. This upward motion may also cause the slips 414 and the upper slip housing 470 to move axially upwardly against the force of the spring stack 468, which is optionally a Belleville spring stack.
Because the outer piston housing 476 may be moveable to expand the slips 414 rather than the piston 480, the anchor assembly 410 design may not use a redundant piston stroke, and the anchor assembly 410 may maintain approximately the same axial length in the collapsed position of FIG. 12 and in the expanded position. The anchor assembly 410 may also have a shorter mandrel 457 as compared to other anchors, and the slips 414 may be nearly unidirectional. Therefore, the spring stack 468 can act as a means to store up energy. If the spring stack 468 were not present, the energy stored in the anchor assembly 410 could be based on how much the mandrel 457 stretches as the slips 414 are set against a wall of the wellbore. Although the mandrel 457 is made of a hard metal, such as steel, it still stretches a small amount, acting as a very stiff spring. Therefore, in order to store up energy in the anchor assembly 410, this spring effect may be weakened or unstiffened to some degree, such as by adding the spring stack 468. In so doing, the stroke length for setting the slips 414 may be increased.
The anchor assembly 410 may also be configured for operation within wellbores having a range of diameters. In an embodiment, a spacer screw 496 may be provided to maintain a space between the lower slip housing 472 and the upper slip housing 470 when the anchor assembly 410 is in its maximum expanded position. During assembly of the anchor assembly 410, when installing the slips 414, the upper slip housing 470 and the lower slip housing 472 may be abutted against each other, and extensions in the slips 414 may be aligned with the channels 494 in the recesses 474 of the slip housings 470, 472. Then the upper and lower slip housings 470, 472 may be pulled apart and the slips 414 can collapse into the anchor assembly 410 around the mandrel 457. To guard against the anchor assembly 410 overstroking downhole, the spacer screw 496 can restrict the upper and lower slip housing 470, 472 from abutting together as during assembly, thereby restricting the slips 414 from falling out of the anchor assembly 410. Thus, in the maximum expanded position, the spacer screw 496 may provide a stop surface against which the lower slip housing 472 may be restricted, and potentially prevented, from further upward movement so that it remains spaced apart from the upper slip housing 470. The spacer screw 496 can be provided as a safety mechanism because the slips 414 should engage the wellbore wall in an intermediate expanded position, well before the lower slip housing 472 engages the spacer screw 496.
Thus, the anchor assembly 410 may be fully operational over a wide range of diameters, and can have an expanded position that varies depending on the diameter of the wellbore. As such, the anchor assembly 410 may be specifically designed to provide proper anchoring of a coring, drilling, or other assembly to withstand compression, tension, and torque for a range of wellbore diameters. Specifically, the anchor assembly 410 is configured to expand up to at least 1.5 times the collapsed diameter of the anchor assembly 410. For example, in one embodiment, the anchor assembly 410 has a collapsed diameter of approximately 8.2 inches (208 mm) and is designed to expand into engagement with an 8½ inch (216 mm) diameter wellbore up to a 12¼ inch (311 mm) diameter wellbore. Where the anchor assembly 410 is used in a cased wellbore, an anchor assembly 410 having a diameter of approximately 8.2 inches (208 mm) may correspond generally to a 9⅝ inch (244 mm) casing up to 13⅜ inch (340 mm) casing.
Once the slips 414 are expanded into gripping engagement with a wellbore, to prevent the anchor assembly 410 from returning to a collapsed position until so desired, the anchor assembly 410 may include a locking subassembly 482. As the piston housing 476 moves, so too may a lock housing 488 that is connected thereto via shear screws 486 mounted about the mandrel 457. As shown in FIG. 14, the lock housing 488 may cooperate with a lock nut 490, which can interact with the mandrel 457 to restrict or prevent release of the anchor assembly 410 when hydraulic fluid pressure is released. Specifically, the outer radial surface of mandrel 457 may include one or more serrations which cooperate with inverse serrations formed on the inner surface of the locking nut 490. Thus, as the piston housing 476 moves the lock housing 488 upwardly, the locking nut 490 can also move upwardly in conjunction therewith, causing the serrations of the locking nut 490 to move over the serrations of the mandrel 457. The serrations on the mandrel 457 may be one-way serrations that allow the locking nut 490 and the components that are connected thereto to move upstream when hydraulic pressure is applied to the anchor assembly 410. Therefore, because of the ramped shape of the serrations, the locking nut 490 may be permitted to move in one direction, namely upstream, with respect to the mandrel 457. The interacting serrations can restrict or prevent movement in the downstream direction since there may be no ramp on the mandrel serrations that angle in that direction. Thus, interacting edges of the serrations can facilitate movement in a single direction, thereby restricting the anchor assembly 410 from returning to a collapsed position until so desired.
In an embodiment, the locking nut 490 may be machined as a hoop and then split into multiple segments. A spring 498 (e.g., a garter spring) may be provided to hold the segments of the locking nut 490 around the mandrel 457. The spring 498 may resemble an O-ring, except that the spring 498 can be made out of wire. Such wire may be looped around the locking nut 490, and the ends can be hooked together. The spring 498 may allow the sections of the locking nut 490 to open and close as the locking nut 490 jumps over each individual serration as it moves upwardly on the mandrel 457. Thus, the spring 498 may allow the locking nut 490 to slide up the ramp of a mandrel serration and jump over to the next serration, thereby ratcheting itself up the mandrel 457. The spring 498 can also hold the locking nut 490 segments together so that the locking nut 490 cannot back up over the serrations on the mandrel 457.
The anchor assembly 410 may also designed to return from an expanded position to a released, collapsed position. For instance, as discussed herein with respect to the coring systems 100, 200, and 300, some embodiments of a coring system contemplate a system in which an anchor may be set (e.g., expanded), a core sample extracted, the anchor released (e.g., retracted), and a coring assembly and anchor retrieved, within a single trip. The anchor assembly 410 may therefore be used in such embodiments to allow the anchor to be released, which may allow another component, such as a deflector assembly, to be released and retrieved.
The anchor assembly 410 of FIGS. 12-14 can be released from gripping engagement with a surrounding wellbore wall by applying an upwardly directed force sufficient to allow the slips 414 to retract to the released and collapsed position shown in FIG. 12. In particular, the lock housing 488 shown in FIG. 14 may be connected to the piston housing 476 by shear screws 486. To return the anchor assembly 410 to a collapsed position, an axial force can be applied to the anchor assembly 410 sufficient to shear the shear screws 486, thereby releasing the locking subassembly 482. As shown in FIG. 12, a release ring 499 may be disposed between the upper slip housing 470 and the mandrel 457. In one aspect, the release ring 499 can provide a shoulder to restrict the upper slip housing 470 from sliding too far downwardly with respect to the slips 414 in the run-in, retracted position of FIG. 12, or after releasing the anchor assembly 410 to the position shown in FIG. 12. In another aspect the release ring 499 may be configured to allow the mandrel 457 to move a small distance axially before the slips 414 disengage from the wellbore to allow for the shear screws 486 to shear completely. Thus, when an axial force is applied to the mandrel 457, the release ring 499 can allow for the slips 414 to maintain engagement with the wellbore to provide a counter force against which the shear screws 486 can shear. Therefore, the release ring 499 can allow the shear screws 486 to shear completely, which enables the slips 414 to collapse back into the anchor assembly 410. With the anchor assembly 410 in the released and collapsed position of FIG. 12, the anchor assembly 410 can be removed from the wellbore.
In accordance with one embodiment, the anchor assembly 410 of FIGS. 12-14 may be used in connection with a coring system 200 of FIGS. 4-8 or a coring system 300 of FIGS. 9-11. It should be appreciated in view of the disclosure herein, that when connected to the anchor assembly 410, a coring system 200, 300 may be used to expand and engage the slips 414 against a wellbore and anchor a corresponding deflector assembly 208, 308 in place. Optional hydraulic lines (see FIG. 2) may be used to provide hydraulic fluid to expand the slips 414.
When a core sample has been obtained, the anchor assembly 410 may be released by applying an upwardly directed force to retract the slips 414 as discussed herein. For instance, as shown in FIGS. 4-8, a collar 244 of a coring assembly 206 may engage a sleeve 246 of a deflector assembly 208. By pulling upwardly on the coring assembly 206, a corresponding upward force can be applied to the deflector assembly, which may also be connected to the mandrel 447 of the anchor assembly 410. Such upward force, if sufficient to shear the shear screws 486, may allow the slips 414 to retract, thereby allowing the coring assembly 206, deflector assembly 208, and anchor assembly 410 to be removed. A similar process may be used with the coring system 300 of FIGS. 9-11, in which a collar 344 or a coring assembly 306 may engage a shoulder 346 of a deflector assembly 308 to exert an upward force that may release the slips 414 of the anchor assembly 410.
Accordingly, the various embodiments disclosed herein include components and structures that are interchangeable, and may be combined to obtain any number of aspects of the present disclosure. For instance, in a single trip, a deflector may be anchored in place, a core sample extracted, the deflector released, and the deflector and coring assembly removed. In the same or other embodiments, the coring system may potentially be used at multiple locations along a wellbore. For instance, the deflector and coring assembly may be lowered to a desired location and anchored in place. The coring assembly may then be used to extract a core sample, and the deflector can be released. The coring assembly and deflector may then be raised or lowered to another location, where the process is repeated by anchoring the deflector, extracting a core sample, and potentially releasing the anchored deflector. Such a process may be repeated multiple times to obtain core samples at multiple vertical locations, and within a single trip.
To facilitate obtaining core samples at multiple locations in a single trip, the anchor assembly 410 may be modified in a number of different manners. For instance, a motor, power source, and wireless transponder may be provided. The motor may mechanically move the slips 414 and/or the mandrel 457 to allow selective expansion and retraction of the slips 414. Thus, the shear screws 486 are optional, and multiple engagements may occur along a length of a wellbore.
Although only a few example implementations have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the example implementation without materially departing from the disclosure of “Singe-Trip Lateral Coring Systems and Methods.” Accordingly, any such modifications are intended to be included in the scope of this disclosure. Likewise, while the disclosure herein contains many specifics, these specifics should not be construed as limiting the scope of the disclosure or of any of the appended claims, but merely as providing information pertinent to one or more specific implementations that may fall within the scope of the disclosure and the appended claims. Any described features from the various implementations disclosed may be employed in combination. In addition, other implementations of the present disclosure may also be devised which lie within the scopes of the disclosure and the appended claims. Additions, deletions and modifications to the implementations that fall within the meaning and scopes of the claims are to be embraced by the claims.
In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures. It is the express intention of the applicant not to invoke 35 U.S.C. §112, paragraph 6 for any limitations of any of the claims herein, except for those in which the claim expressly uses the words ‘means for’ together with an associated function.
Certain implementations and features may have been described using a set of numerical upper limits and a set of numerical lower limits. It should be appreciated that ranges including the combination of any two values, e.g., the combination of any lower value with any upper value, the combination of any two lower values, and/or the combination of any two upper values are contemplated unless otherwise indicated. Certain lower limits, upper limits and ranges may appear in one or more claims below. Numerical values are “about” or “approximately” the indicated value, and take into account experimental error and variations that would be expected by a person having ordinary skill in the art.

Claims

What is claimed is:

1. A single-trip coring system, comprising:

a coring assembly including a core barrel for capturing a core sample, and a coring bit coupled to the core barrel;

a deflector for deflecting the coring assembly into a formation for drilling a lateral section of a borehole; and

a releasable attachment between the coring assembly and the deflector.

2. The single-trip coring system recited in claim 1, the releasable attachment including a sacrificial element.

3. The single-trip coring system recited in claim 1, the core barrel including a collection chamber and one or more of:

an outer core barrel; or

an inner core barrel.

4. The single-trip coring system recited in claim 1, further comprising:

an expandable anchor coupled to the deflector.

5. The single-trip coring system recited in claim 1, further comprising:

a collar coupled to the coring bit; and

a sleeve coupled to the deflector, the sleeve including an interior chamber through which the core barrel extends, the interior chamber being sized to restrict movement of the collar through the interior chamber.

6. The single-trip coring system recited in claim 5, the collar being configured to move with the coring bit, and the sleeve being configured to remain stationary while the coring bit moves following release of the releasable attachment.

7. The single-trip coring system recited in claim 1, the core barrel being rotatable within the sleeve.

8. The single-trip coring system recited in claim 1, further comprising:

a collar connected to the coring bit; and

a shoulder connected to the deflector, the shoulder being sized to create a passageway with a sidewall of a wellbore, the passageway permitting the core barrel to extend therethrough while restricting movement of the collar therethrough.

9. The single-trip coring system recited in claim 8, the shoulder being configured to remain stationary relative to the sleeve, while the collar is configured to move axially with the coring bit.

10. The single-trip coring system recited in claim 9, the core barrel being configured to be rotatable within the collar.

11. The single-trip coring system recited in claim 8, the deflector including a track for mating with the collar.

12. A method for single-trip drilling of a lateral borehole and extracting a core sample therefrom, comprising:

inserting a coring system into a wellbore within a formation, the coring system including a coring assembly coupled to a deflector assembly;

anchoring the deflector assembly within the wellbore;

releasing a coupling between the coring assembly and the deflector assembly;

drilling a lateral borehole using the coring assembly while simultaneously obtaining a core sample from the formation; and

removing the core sample and at least a portion of the coring assembly from the borehole.

13. The method recited in claim 12, further comprising:

un-anchoring the deflector assembly within the borehole; and

collectively removing the deflector assembly and coring assembly from the borehole following obtaining of the core sample from the formation.

14. The method recited in claim 13, the method further comprising:

obtaining at least one additional core sample through the lateral borehole, prior to removing the deflector assembly and coring assembly from the borehole.

15. The method recited in claim 13, wherein collectively removing the deflector assembly and coring assembly includes:

retracting a the coring assembly from the lateral borehole;

engaging a collar of the coring assembly against a stop surface of the deflector assembly; and

pulling upwardly on the coring assembly and thereby un-anchoring the deflector assembly.

16. The method recited in claim 12, wherein obtaining the core sample from the borehole includes obtaining a core sample having a size and construction sufficient to determine porosity.

17. The method recited in claim 12, wherein anchoring the deflector assembly includes anchoring the deflector assembly at a first location within the wellbore, the method further comprising:

un-anchoring the deflector at the first location within the wellbore;

anchoring the deflector at a second location within the wellbore;

obtaining at least one additional core sample at an additional lateral borehole corresponding to the second location within the wellbore; and

removing the at least one additional core sample from the wellbore.

18. The method recited in claim 12, wherein drilling the lateral borehole includes obtaining a continuous core sample along a length of the lateral wellbore.

19. A single-trip coring system, comprising:

a coring assembly including an outer core barrel coupled to a coring bit;

a deflector assembly having a ramp face;

a sacrificial element coupling the coring assembly to the deflector assembly; and

an anchor assembly coupled to the deflector assembly, the anchor assembly including a plurality of expandable slips.

20. The single-trip coring system recited in claim 19, wherein:

the coring assembly includes a collar coupled to the coring bit, the collar being configured to move axially with the coring bit upon selective release by the sacrificial element; and

the deflector assembly includes a stop surface for retrieving the deflector assembly by engaging the collar and restricting passage of the collar upwardly past the stop surface.