SINGLE-TRIP LATERAL CORING SYSTEMS AND METHODS

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.

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 toFIG. 1, an example coring system100is illustrated. The coring system100ofFIG. 1may be inserted within a wellbore102in a formation104, and used to extract a core sample of the formation104. In some embodiments, the core sample extracted from the formation may be core sample removed from a lateral or deviated perforation of the wellbore102, rather than from a vertical portion of the wellbore102.

In the particular embodiment illustrated inFIG. 1, the coring system100is shown as including a coring assembly106, a deflector assembly108, and an anchor assembly110, each of which are optionally interconnected. As discussed in greater detail herein, for instance, the coring assembly106may be connected to the deflector assembly108, and the coring assembly106, deflector assembly108, and anchor assembly110may collectively be inserted and run into the wellbore102, and lowered to a desired position. When at the desired location, the anchor assembly110may be secured in place. For instance, in this embodiment, the anchor assembly110includes an anchor112and expandable slips114that may engage the inner surface of the wellbore102, although the anchor assembly110may include any suitable construction, and may be integral with, or distinct from, the deflector assembly108. A frictional or other engagement between the expandable slips114and the inner surface of the wellbore102may effectively hold the anchor112and the deflector assembly108at a desired axial position, and potentially at a desired orientation, within the wellbore102.

The coring assembly106may be separable from the deflector assembly108in an embodiment in which the coring assembly106is connected to the deflector assembly108and/or the anchor assembly110. By way of illustration, a selectively engageable latch or other mechanism may be used to selectively connect and/or disconnect the coring assembly106relative to a deflector116of the deflector assembly108. In other embodiments, and as described in greater detail hereafter, a sacrificial element may be used to connect the coring assembly106to the deflector assembly108. For instance, once the anchor assembly110is secured at an axial and/or rotational position within the wellbore102, axial and/or rotational movement of the coring assembly106may be used to break a sacrificial element, thereby disconnecting the coring assembly106from the deflector116.

While the coring assembly106, deflector assembly108, and anchor assembly110may be collectively run into the wellbore102to allow a single trip to insert, anchor, and use such assemblies, such an embodiment is merely illustrative. In other embodiments, for instance, the coring assembly106may be separate from the deflector assembly108. In such an embodiment, the anchor assembly110may be anchored in place. Thereafter, the coring assembly106may be run into the wellbore102. Of course, the deflector assembly108may be run into the wellbore102and secured in a desired position and orientation collectively with the anchor assembly110, or run in and secured in place following insertion and/or anchoring of the anchor assembly110.

Regardless of whether the coring assembly106is connected to the anchor assembly110and/or deflector assembly108to allow for single-trip extraction of a core sample, the coring assembly106may use the deflector assembly108to extract a core sample from the wellbore102, and potentially a deviated or lateral section of the wellbore102as discussed hereafter. For instance, as shown inFIG. 1and as better viewed in the enlarged view ofFIG. 2, the coring assembly106may include a coring bit118for drilling into the formation104and extracting a core sample therefrom. The coring bit118may be connected to an outer barrel120(e.g., using threaded connector122), and core samples may collect within the coring bit118and/or the outer barrel120.

In particular, the coring bit118may include an opening124in a distal end thereof, which opening124may be in communication with a collection chamber126within the coring bit118and/or the outer barrel120. The coring bit118and the outer barrel120may be connected to a drill rig (not shown) that can rotate the coring bit118, optionally by also rotating the outer barrel120and/or a drill string (not shown) attached to the outer barrel120. As one or more cutters128on the coring bit118cut into the formation104, materials from the formation may collect within the collection chamber126to form a columnar core sample. When the coring bit118has cut deep enough to fill the collection chamber126, or otherwise obtain a sample for study, the core sample can be removed. To remove the core sample, the entire coring assembly106could be withdrawn from the wellbore102.

In another embodiment, however, a core sample may be obtained and removed without corresponding removal of the coring assembly106. For instance, in this particular embodiment, an inner barrel130may be located within the collection chamber126. The inner barrel130may be selectively removable and can include an interior opening which may also act as a collection chamber. As shown inFIGS. 1 and 2, for instance, a retrieval wire132may be connected to an upper end of the inner barrel130. When the core sample is desired, the inner barrel130may be lowered into the coring assembly106. The core barrel130may be located at any desired position, including adjacent the distal end of the coring bit118. As the coring bit118then drills the wellbore102, or cuts a lateral section into the wellbore102, the core sample may collect inside the collection chamber of the inner barrel130. When the inner barrel130is filled or otherwise has a core sample of a desired size, an operator may use the retrieval wire132to remove the inner barrel130and extract the core sample. If additional core samples are desired, the inner barrel130(or a different inner barrel130) may be lowered towards the coring bit118, and drilling may continue until another core sample is obtained.

A core sample collected within the collection chamber126of the outer barrel120or the inner barrel130may 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 opening124and collection chamber126(or the interior of the inner barrel130) may have a width from about one inch (25 mm) to about four inches (102 mm). In a more particular embodiment, the inner barrel130and/or outer barrel120may collect a core sample having a width greater than two inches (51 mm), which can facilitate measuring porosity of the formation104. 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 barrel120and/or inner barrel130may in other embodiments facilitate collection of a columnar core sample having a square, elliptical, trapezoidal, or other cross-sectional shape.

The coring assembly106may include any number of additional or other components. For instance, the inner barrel130and collection chamber126may be illustrated inFIGS. 1 and 2somewhat schematically. In some embodiments, the inner barrel130and/or collection chamber126may include fasteners to secure the inner barrel130in place within the outer barrel120and/or the coring bit118. Such fasteners may be selectively engageable and disengageable to allow removal of the inner barrel130independent of the outer barrel120or the coring assembly106.

As also seen inFIG. 2, an example coring assembly106may also include one or more hydraulic lines134,136. In this particular embodiment, fluid may be pumped through a channel138in the outer barrel120, and directed towards the coring bit118. The channel138of this embodiment is shown as surrounding the collection chamber126; however, in other embodiments the channel138may be otherwise located or omitted entirely. As fluid is sent through the channel138, it may pass into one or more hydraulic lines134within the coring bit118or outer barrel120. Such fluid may then be used as a cutting fluid to facilitate cutting by the coring bit118.

In another embodiment, fluid passing through the hydraulic line134and/or the channel138may be used for additional or other purposes. For instance, the embodiment shown inFIG. 2illustrates an additional hydraulic line136outside of the coring bit118. The illustrated hydraulic line136is shown as extending to the deflector116, but may extend to any desired location, and can be used for any suitable purposes. For instance, referring again toFIG. 1, the coring assembly106may be connected directly or indirectly to an anchor assembly110, and one or more expandable slips114may be selectively expanded or retracted using hydraulic fluid supplied by the hydraulic line134. When expanded, the expandable slips114may engage the wellbore102and anchor the deflector116in place. Thereafter, the coring assembly106may be inserted into the wellbore102, or detached from the deflector116, to begin a coring process.

More particularly, as noted above, some embodiments of the present disclosure relate to using the coring assembly106to extract a core sample from a lateral section or perforation of the wellbore102. Turning now toFIG. 3, the example coring system100ofFIG. 1is shown in additional detail, while extracting a lateral core sample.

In general, the deflector116may be used to deflect the coring assembly106laterally to create a deviated or lateral section103in the wellbore102. As the deflection occurs, the coring assembly106may drill laterally into the formation104and extract a core sample from the lateral section103of the wellbore102, as opposed to a vertical or other primary section of the wellbore102. InFIGS. 1 and 3for instance, the deflector116is shown as being generally wedge-shaped, and having a ramp face140. The particular incline of the ramp face140may be varied in any number of manners. For instance, relative to the longitudinal axis of the vertical portion of the wellbore102, the ramp face140may 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 face140may be about 3°. Of course, in other embodiments, the ramp face140may be inclined at an angle less than about 1° or more than about 10°.

Further, while the ramp face140may have a single segment extending at a constant incline, in other embodiments the ramp face140may have multiple segments. In this particular embodiment, for instance, the ramp face140is shown as including at least two segments, each with a different degree of incline. In other embodiments, however, the ramp face140may include three or more segments, any or each of which may have a different incline relative to other segments.

As the coring assembly106is detached from the deflector116, or when inserted into the borehole following anchoring of the anchor assembly110and the deflector assembly108, the coring bit118may come into contact with the ramp face140. Because of the angle on the ramp face140, further downward movement of the coring assembly106may cause the coring bit118to travel across the ramp face140, and gradually move towards the sidewall of the wellbore102. The coring bit118may optionally rotate as it moves along the ramp face140and/or as it engages the sidewall of the wellbore102. Using cutting elements, the coring bit118may then cut laterally into the wellbore102and form the lateral section103.

As discussed herein, when the coring bit118forms the lateral section103of the borehole, rock and other materials of the formation104may pass through an opening124in the coring bit118and collect within the collection chamber126and/or an inner barrel130. Ultimately, once a core sample of a desired size has been collected (e.g., when the inner barrel130is filled or near filled), the core sample may be extracted. Extraction of the core sample may occur with or without removal of the coring assembly106, as discussed herein.

One aspect of a coring system100of 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 system100may extend many hundreds of feet (e.g., 1000 feet, 2000 feet, or more) into the lateral section103of the wellbore102. 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 system100wishes to obtain a sample of the formation three feet (0.9 m) away from the wellbore102, as measured in a direction perpendicular to the wellbore102, and the lateral section103extends at a constant angle of 3° relative to the longitudinal axis of the wellbore102, a core sample of about sixty feet (18.3 m) should provide the desired information. Of course, if angle of the lateral section103is 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 wellbore102, the length of the core sample may vary. Further, while the illustrated wellbore102is shown as vertical, a wellbore may not be vertical; however, the coring system100may 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 assembly106laterally from the primary portion of the wellbore102, a core sample may therefore be obtained to capture formation properties further from the main wellbore102. 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 bit118, the coring system100may 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 section103that extends a relatively short distance from the primary portion of the wellbore102, the length may be much larger as noted above. Indeed, the lateral section103may extend for potentially hundreds of feet as discussed herein. Optionally, to facilitate lateral drilling of the lateral section103, the coring assembly106may use directional drilling equipment. While not shown inFIGS. 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 section103. 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 toFIGS. 4-8, an example single-trip coring system200is illustrated in greater detail. In particularFIGS. 4-8illustrate various steps in an example method that may be used to run the coring system in a wellbore202, drill a lateral section of a wellbore202, obtain a core sample, and remove the coring assembly and/or deflector assembly. The single-trip coring system200may share various features with the coring system100ofFIGS. 1-3. To avoid obscuring aspects of the embodiment inFIGS. 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 ofFIGS. 1-3(e.g., an anchor assembly having expandable slips, an inner barrel, hydraulic lines and channels, etc.) may be incorporated into the embodiments ofFIGS. 4-8.

More particularly,FIG. 4illustrates a single-trip coring system200that may include a coring assembly206connected to a deflector assembly208in accordance with some embodiments of the present disclosure. In this particular embodiment, the coring assembly206and deflector assembly208may be connected in a manner that allows the coring assembly206to be run into the wellbore202at the same time as the deflector assembly208.

The coring assembly206and deflector assembly208may be placed in the wellbore202, and lowered to a desired location. The deflector assembly208may include a deflector216with a ramp face240. When the ramp face240is oriented in a direction corresponding to a desired trajectory for a lateral section of the wellbore202, the deflector assembly208can be anchored in place. Following anchoring of the deflector assembly208, the coring assembly206can be separated from the deflector assembly208and moved along the length of the ramp face240to create the lateral section or borehole off the wellbore202, and to take a core sample.

In the particular embodiment shown inFIG. 4, a sacrificial element242may connect the coring assembly206to the deflector assembly208. The illustrated sacrificial element242may extend between the deflector216and a shaft of the coring bit218and/or outer barrel220, but may have any suitable configuration. In operation, the sacrificial element242may be designed to break or fail when a sufficient load is placed thereon. For instance, once the deflector216is anchored in place, an axial load may be placed on the outer barrel220of the coring assembly206(e.g., by loading a drill string). The anchored deflector216may be configured to have a higher resistance to an axial load that the sacrificial element242, such that when the load exceeds the maximum force allowed by the sacrificial element242, the sacrificial element242may break but the deflector216may remain anchored in place.

In another embodiment, the coring assembly206may rotate to break the sacrificial element242. By way of illustration, the coring bit218and/or outer barrel220of the coring assembly206may be configured to rotate to drill a lateral section of the wellbore202. In this embodiment, the coring bit218may be integrated with the outer barrel220, and the sacrificial element242may break when the rotational force is applied to the outer barrel220(e.g., by a surface rig). Regardless of whether the sacrificial element242breaks as a result of axial loading, rotation of the coring assembly206, or in some other manner, the coring assembly206may break free from the deflector assembly208and be allowed to move axially along the wellbore202.

The sacrificial element242may take any number of different forms. InFIG. 4, for instance, the sacrificial element242may be a shear screw or break bolt configured to fail when a load is applied to translate or rotate the coring assembly206relative to the deflector assembly208(e.g., when the deflector assembly208is anchored). In other embodiments, the sacrificial element242may 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 element242may be replaced by other structures, such as a selectively engageable latch that allows selective disconnection and/or reattachment of the coring assembly206relative to the deflector assembly208, without breaking a connector.

Once the sacrificial element242is broken, an operator of the coring system200may move the coring assembly206downwardly, further into the wellbore202. Upon doing so, the coring assembly206may move along a ramp face240of the deflector system208, and can be directed against the interior surface of the wellbore202. The coring bit218can rotate or otherwise be used to cut into the formation204and create a lateral section of the wellbore202. As shown inFIGS. 5 and 6, the coring bit218may progressively cut a lateral section203that deviates laterally relative to a primary or other portion of the wellbore202.

As the coring bit218cuts into the formation204and forms the lateral section203of the wellbore202, the coring bit218may extract samples of the formation204. In this particular embodiment, the coring bit218and the outer barrel220of the coring assembly206define a collection chamber226that is accessible through an opening224in the distal end of the coring bit218. A core sample may therefore collect in the collection chamber226for removal either with the coring assembly206, or independent from removal of the coring assembly206(e.g., using an inner barrel). Multiple core samples may also be obtained without removing the coring assembly206as discussed in greater detail with respect toFIGS. 1-3. Both the outer barrel220and 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 system200may remove the coring assembly206. As shown inFIG. 7, for instance, the coring assembly206may be removed from the lateral section203of the wellbore202by pulling upwardly on the outer barrel220and the coring bit218.

In the embodiment shown inFIGS. 4-7, removal of the coring assembly206may also be used to remove the deflector assembly208. For instance, as shown inFIG. 7, the coring bit218and/or outer barrel220may include, or be connected to, a collar244that extends radially outward from the outer barrel220. The deflector assembly202may, in turn, include or be attached to a sleeve246. In the illustrated embodiment, the sleeve246of the deflector assembly208is shown as defining an opening or passageway through which the outer barrel220of the coring assembly216may pass. The size of the opening may be such that the inner diameter of the opening allows the outer diameter of the outer barrel220to be slideably received thereby. The inner diameter of the opening may, however, be smaller than the outer diameter of the collar244. As a result, when the coring assembly206is pulled back, the collar244may engage the lower surface248of the sleeve246, which lower surface248may act as a stop surface by restricting the collar244from moving upwardly past the lower surface248. To move the coring assembly206upwardly, the deflector assembly208may therefore also be un-anchored and released from engagement with the wellbore202. In embodiments in which the deflector assembly208is anchored in place, the deflector assembly208may be released in any number of manners. A more particular discussion of one manner for releasing the anchored deflector assembly208is discussed in additional detail with respect toFIGS. 12-14.FIG. 8illustrates the coring assembly206moving upwardly and carrying the deflector assembly208, as the anchored position of the deflector assembly208is illustrated in phantom lines.

The sleeve246of the deflector assembly208, and the collar244of the coring assembly206, may be formed or constructed in any number of manners. For instance, the sleeve246may be integrally formed with the deflector216. In another embodiment, such as that shown inFIGS. 4-8, the sleeve246may be mechanically fastened to the deflector216. In this particular embodiment, a fastener250(e.g., a bolt, screw, pin, rivet, or other mechanical fastener, or some combination thereof) may be used to secure the sleeve246within a recess252in the deflector216. When secured in place, the sleeve246is optionally secured to restrict, and potentially prevent, axial and/or rotational movement of the sleeve246along the wellbore202. Thus, while the coring assembly206may move axially and/or rotationally within the wellbore202, the sleeve246may remain static. In a similar manner, the collar244may be integrally formed, or distinct from, the coring bit218and/or the outer sleeve220. Optionally, the collar244may rotate with the drill bit218, although in other embodiments, the collar244may include a bearing or other component to allow rotation of the coring bit218independent of the collar244.

In embodiments in which the sleeve246is static and the coring assembly206passes through the sleeve246, the sleeve246may also be a bearing, or may include one or more bearings or bearing surfaces. For instance, the sleeve246may include one or more bearings or bushings to reduce friction as the coring assembly206moves axially within the opening in the sleeve246or to reduce friction as a result of the coring assembly206rotating within the opening in the sleeve246. An example bearing that may be included as part of the sleeve246, 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 barrel220while the outer barrel220and coring bit218travel along the ramp face240of the deflector assembly208to drill a lateral section into the wellbore202. A spherical bearing may also be used to support axial, sliding motion of the outer barrel220as coring assembly206moves in an upwardly or downwardly directed path.

The fastener250used to connect the sleeve246to the deflector216may also have additional or other properties or structures. For instance, rather than a mechanical fastener, the sleeve246may 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 sleeve246to the deflector216, the attachment may have a greater structural strength when compared to the sacrificial element242. In one embodiment, a greater structural strength of the fastener250or other mechanical attachment may be used to allow the sacrificial element242to break prior to failure of the fastener250, to ensure that the coring assembly206can break free of the deflector216, and remain guided by the fixed sleeve246.

Another aspect of the present disclosure, as shown inFIGS. 7 and 8, includes for extracting a core sample by creating a lateral section203of the wellbore202, 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 comparingFIGS. 7 and 8, while a lateral section203may be created, the lateral section203may act as a perforation of the primary portion of the wellbore202. Rocks or other materials of the formation204may be positioned between the lateral section203or borehole and the primary wellbore (seeFIG. 7), but may wash out to connect the distal end of the lateral section203with the primary portion of the wellbore202(seeFIG. 8). Washing out the lateral section203may be particularly likely when the length of the lateral section203, or the maximum lateral offset from the vertical portion of the wellbore202, is relatively short. Removing the coring assembly206in such embodiments may also facilitate wash outs such that the lateral section203or borehole may merely be a widened portion of the wellbore202, rather than a separate bore or well. A wash out may also be particularly likely when the wellbore202is an uncased or openhole wellbore as shown inFIGS. 4-8, although in other embodiments a cased wellbore may be used.

Turning now toFIGS. 9-11, another embodiment of a coring system300is shown in additional detail. In particular,FIGS. 9-11illustrate various elements of a method for anchoring a deflection assembly308and extracting a core sample in a single trip. Retrieval of the deflection assembly308may also include release of the deflection assembly308in some embodiments.

In general, the coring system300ofFIGS. 9-11may be relatively similar to the coring system200ofFIGS. 4-8. For instance, the coring system300may include a coring assembly306that is connected to the deflection assembly308using a sacrificial element342or some other releasable connector. When inserting the coring assembly306and the deflection assembly308into the wellbore302formed in the formation304, the sacrificial element342may be in an engaged or unbroken state that maintains the relative position of the coring assembly306relative to the deflection assembly308. By selectively disengaging a releasable connector, or by causing the sacrificial element342to fail (e.g., using axial motion following anchoring of the deflector assembly308, or by rotating a coring bit318of the coring assembly306), the coring assembly306may move axially along the wellbore302while the deflector316remains anchored in place.

In the particular embodiment shown inFIGS. 9-11, the coring assembly306may include a coring bit318that can be mechanically attached to an outer barrel320. In particular, this embodiment illustrates a threaded connector322between the coring bit318and the outer barrel320. Using the threaded connector322, the coring bit318may be selectively attached, removed, replaced, and the like. In other embodiments, the coring it318may be integrally formed with the outer barrel320, or may be attached to the outer barrel320or a drill string (not shown) in other manners.

In general, the coring bit318may act in a manner similar to other coring bits described herein. InFIG. 9, for instance, the coring bit318is shown as including an opening324in the distal end thereof, and which facilitates the collection of a core sample. For instance, as the coring bit318drills laterally into the formation304(seeFIG. 10), materials from the formation304may enter the opening324and 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 assembly306, and/or collection of multiple, different core samples in a single trip of the coring assembly306, whether collected along a single lateral section303or at multiple lateral sections.

InFIG. 9, the illustrated coring assembly306is shown as including a collar344connected to the coring bit318and/or the outer barrel320. In particular, the illustrated collar344may include an interior opening into which the outer diameter of an upper portion of the coring bit318may be positioned. Optionally, the collar344has a fixed axial position along the coring assembly306. Thus, once the coring assembly306is detached from the deflector assembly308, the collar344may move along the deflector316along with the coring bit318. While the illustrated embodiment illustrates the collar344positioned around the coring bit318, in other embodiments the collar344may be secured to, or may encompass, a portion of the outer barrel320.

The collar344may be used to guide the coring bit318in accordance with some embodiments of the present disclosure. In this particular embodiment, for instance, the deflector316of the deflector assembly308may include a track340for interfacing with the collar344. The shape, size, and configuration of the track340may match that of the collar344. For instance, the track340may have a concave surface with a contour to match an outer contour of the collar344. In another embodiment, the track340may include a rail, guide, or other similar component that may correspond to the collar344and/or facilitate movement of the collar344along the track340.

As the collar344moves downwardly and laterally along the track340, the coring bit318may also move. The track340may be inclined relative to the longitudinal axis of the wellbore302, thereby causing the coring bit318to ultimately engage a sidewall of the wellbore302. By rotating the coring bit318, the coring bit318can also cut into the sidewall at a trajectory corresponding to the configuration of the track340. As shown inFIG. 10, for instance, the track340may guide the coring bit318as it creates a lateral section303of the wellbore302. Of course, as the lateral section303is created, a core sample of the lateral section of the formation304may also be formed within the collection chamber326of the coring assembly306.

Once the desired core samples are obtained, the coring assembly306may be removed as shown inFIG. 11. In particular, the outer barrel320may be connected to a drill string, and can be pulled upwardly. As the outer barrel320is pulled upwardly, the coring bit318may move out of the lateral section303of the wellbore302, and towards an upper portion of the deflector assembly308. In this particular embodiment, the upper portion of the deflector assembly defines a shoulder346. More particularly, the coring bit318and the collar344may follow the track340. The track340may direct the collar344of the coring assembly306against the shoulder346, which can act as a stop surface to restrict the collar344from moving upwardly past the shoulder346. The shoulder346may be sized so that the distance between the shoulder246and the sidewall of the wellbore302defines a passageway with sufficient size to allow the outer barrel326to slideably move therebetween. The collar344may, however, have an increased radial size, and may not fit in the passageway between the shoulder346and the sidewall of the wellbore302. As a result, the collar344may engage the shoulder346, which can restrict, and potentially prevent, the collar344from moving past the shoulder346.

When pulling upwardly on the outer barrel326, the coring assembly306may be used to retrieve the deflector assembly308from the wellbore302. For instance, as discussed herein, the deflector assembly308may be selectively released from its anchored position within the wellbore302. Following un-anchoring of the deflector assembly308(e.g., by releasing an anchor assembly connected to the deflector assembly308), an upwardly-directed force on the coring assembly306may also cause the deflector assembly308to move upwardly by virtue of the engagement between the collar344and the shoulder346.

The collar344of the embodiment shown inFIGS. 9-11may have a number of different constructions. In one embodiment, for instance, the collar344may be integrally formed with the coring bit318and/or outer barrel320, and may rotate with the coring bit318when it rotates and digs the lateral section303of the wellbore302. In the illustrated embodiment, however, the collar344may also be separately formed and then attached to the coring assembly306. The interior opening of the collar344may have a size sufficient to allow the coring bit318to be positioned therein. Optionally, the coring bit318may float within the collar344. For instance, the collar344may be configured not to rotate with the coring bit318. One or more bearings or other components may be used to facilitate rotation of the coring bit318within the collar344. In one embodiment, the collar344includes a groove, notch or other structure that mates with a corresponding structure of the track340. As a result, as the coring assembly306moves along the track340, the drill bit318may rotate while the track340may restrict rotation of the collar344.

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 assembly410that may be used in connection with embodiments of the present disclosure is shown in additional detail inFIGS. 12-14. This particular anchor assembly includes an anchor body412and one or more expandable slips414. More particularly, as described in greater detail below, hydraulic fluid passing through the anchor body412may be used to selectively expand the expandable slips414, which may then engage the exterior wall around a wellbore.

FIGS. 12-14depict the example embodiment of an anchor assembly410, with various operational positions. In one embodiment, the anchor assembly410may 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 assembly410may 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 assembly410may be used. For instance, the anchor assembly410may 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. 12-14provide an operational overview of the anchor assembly410. In particular, the anchor assembly410may be lowered into an uncased wellbore in a locked and collapsed position shown inFIGS. 12 and 13. When the anchor assembly410reaches a desired depth, the anchor assembly410may be unlocked and expanded to a set position shown in phantom lines inFIGS. 12 and 13, where expandable slips414of the anchor assembly410may engage a surrounding open wellbore wall, or a casing. The anchor assembly410may be configured to expand over a range of diameters, andFIGS. 12 and 13depict the anchor assembly410, with the maximum expanded configuration shown in phantom lines. Finally, to remove the anchor assembly410from the well, the anchor assembly410may be released from the casing to return to an unlocked and collapsed position as shown inFIG. 12.

The anchor assembly410may generally comprise a top sub454connected via threads456to a generally cylindrical mandrel457having a fluid channel466therethrough, which in turn is connected via threads456to a nose458. In one embodiment, the anchor assembly410may include an upper box connection460and a lower pin connection462for connecting the anchor assembly410into a downhole assembly. The upper box connection460may be connected to the lower end of a deflector assembly408, for example. Optionally, a pipe plug464may be connected to the nose458to close off a fluid channel466of the mandrel457so that the anchor assembly410may be expanded hydraulically.

The mandrel457may be the innermost component within the anchor assembly410. Disposed around and slidingly engaging the mandrel457is a spring stack468in the illustrated embodiment, along with an upper slip housing470, one or more slips414, and lower slip housing472. One or more recesses474may be formed in the slip housings470,472to accommodate the radial movement of the one or more slips414. The recesses474may include angled channels formed into the wall thereof, and these channels may provide a drive mechanism for the slips414to move radially outwardly into the expanded positions depicted in phantom lines inFIGS. 12 and 13. In one embodiment, the anchor assembly410may comprise three slips414as shown inFIG. 13, wherein the three slips414may be spaced at 120° intervals circumferentially around the anchor assembly410, and in the same radial plane. It should be appreciated, however, that any number of slips414may be disposed in the same radial plane around the anchor assembly410. For example, the anchor assembly410may comprise four slips414, each approximately 90° from each other, two slips414, each approximately 180° from each other, or any number of slips414. Further, while the slips414may be offset at equal angular intervals, other embodiments contemplate such offsets being varied. For instance, when three slips414are used, the one slip414may be spaced about 90° from one slip414and about 135° from another slip414.

In the embodiment shown inFIG. 12, a piston housing476may be connected to the lower slip housing472(e.g., using threads). The piston housing476may form a fluid chamber478around the mandrel457within which a piston480and a locking subassembly482may be disposed. The piston480may connect to the mandrel457(e.g., using threads), and the mandrel457may include ports484that enable fluid flow from the flowbore466into the fluid chamber478to actuate the anchor assembly410to the expanded position shown in phantom lines inFIGS. 12 and 13. In one embodiment, a seal may be provided between the piston480and the mandrel457, between the piston480and the piston housing476, and/or between the piston housing476and the lower slip housing472.

FIG. 14depicts an enlarged view of the locking subassembly482, shown releasably coupled to the piston housing476via one or more shear screws486. The locking subassembly482shown inFIG. 14may include a lock housing488mounted about the mandrel457, and a lock nut490, which interacts with the mandrel457to prevent release of the anchor assembly410when pressure is released. The outer radial surface of mandrel457may include serrations which cooperate with inverse serrations formed on the inner surface of locking nut490, as described in more detail below.

Referring now toFIGS. 12 and 13, the anchor assembly410is illustrated with the slips414in a retracted position which allows the anchor assembly410to be inserted into a wellbore. When the slips414are expanded to the position illustrated in phantom lines inFIGS. 12 and 13, the slips414may be in an expanded position, in which the slips414extend radially outwardly into gripping engagement with a surrounding open wellbore wall or casing. The anchor assembly410may have two operational positions within a particular wellbore—namely a collapsed position as shown inFIGS. 12 and 13for running the anchor into a wellbore, and an expanded position as shown in phantom lines inFIGS. 12 and 13, for grippingly engaging a wellbore.

To actuate the anchor assembly410, hydraulic forces may be applied to cause the slips414to expand radially outwardly from the locked and collapsed position ofFIGS. 12 and 13to the unlocked and expanded position shown in phantom lines. Specifically, fluid may flow down the fluid channel466and through the ports484in the mandrel457into the chamber478surrounded by the piston housing476. When the anchor assembly410is the lowermost tool in a drilling, coring, or other system, the pipe plug464may be used to close off the fluid channel466through the mandrel457to allow fluid pressure to build up within the anchor assembly410to actuate it (e.g., by radially expanding the slips414of the anchor assembly410). If, however, another tool is run below the anchor assembly410, the pipe plug464may be removed so that hydraulic fluid can flow through the anchor assembly410to 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 assembly410to actuate both tools.

Pressure may continue to build in the fluid chamber478as the piston480provides a seal therein until the pressure is sufficient to cause shear screws492to shear. Since the piston480may be connected to the mandrel457, the piston480may remain stationary while the outer piston housing476and the lower slip housing472connected thereto may move axially upwardly from the position shown inFIG. 12. Upward movement of the lower slip housing472can act against the slips414to drive the slips414radially outwardly along the channels494. This upward motion may also cause the slips414and the upper slip housing470to move axially upwardly against the force of the spring stack468, which is optionally a Belleville spring stack.

Because the outer piston housing476may be moveable to expand the slips414rather than the piston480, the anchor assembly410design may not use a redundant piston stroke, and the anchor assembly410may maintain approximately the same axial length in the collapsed position ofFIG. 12and in the expanded position. The anchor assembly410may also have a shorter mandrel457as compared to other anchors, and the slips414may be nearly unidirectional. Therefore, the spring stack468can act as a means to store up energy. If the spring stack468were not present, the energy stored in the anchor assembly410could be based on how much the mandrel457stretches as the slips414are set against a wall of the wellbore. Although the mandrel457is 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 assembly410, this spring effect may be weakened or unstiffened to some degree, such as by adding the spring stack468. In so doing, the stroke length for setting the slips414may be increased.

The anchor assembly410may also be configured for operation within wellbores having a range of diameters. In an embodiment, a spacer screw496may be provided to maintain a space between the lower slip housing472and the upper slip housing470when the anchor assembly410is in its maximum expanded position. During assembly of the anchor assembly410, when installing the slips414, the upper slip housing470and the lower slip housing472may be abutted against each other, and extensions in the slips414may be aligned with the channels494in the recesses474of the slip housings470,472. Then the upper and lower slip housings470,472may be pulled apart and the slips414can collapse into the anchor assembly410around the mandrel457. To guard against the anchor assembly410overstroking downhole, the spacer screw496can restrict the upper and lower slip housing470,472from abutting together as during assembly, thereby restricting the slips414from falling out of the anchor assembly410. Thus, in the maximum expanded position, the spacer screw496may provide a stop surface against which the lower slip housing472may be restricted, and potentially prevented, from further upward movement so that it remains spaced apart from the upper slip housing470. The spacer screw496can be provided as a safety mechanism because the slips414should engage the wellbore wall in an intermediate expanded position, well before the lower slip housing472engages the spacer screw496.

Thus, the anchor assembly410may 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 assembly410may 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 assembly410is configured to expand up to at least 1.5 times the collapsed diameter of the anchor assembly410. For example, in one embodiment, the anchor assembly410has 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 assembly410is used in a cased wellbore, an anchor assembly410having 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 slips414are expanded into gripping engagement with a wellbore, to prevent the anchor assembly410from returning to a collapsed position until so desired, the anchor assembly410may include a locking subassembly482. As the piston housing476moves, so too may a lock housing488that is connected thereto via shear screws486mounted about the mandrel457. As shown inFIG. 14, the lock housing488may cooperate with a lock nut490, which can interact with the mandrel457to restrict or prevent release of the anchor assembly410when hydraulic fluid pressure is released. Specifically, the outer radial surface of mandrel457may include one or more serrations which cooperate with inverse serrations formed on the inner surface of the locking nut490. Thus, as the piston housing476moves the lock housing488upwardly, the locking nut490can also move upwardly in conjunction therewith, causing the serrations of the locking nut490to move over the serrations of the mandrel457. The serrations on the mandrel457may be one-way serrations that allow the locking nut490and the components that are connected thereto to move upstream when hydraulic pressure is applied to the anchor assembly410. Therefore, because of the ramped shape of the serrations, the locking nut490may be permitted to move in one direction, namely upstream, with respect to the mandrel457. 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 assembly410from returning to a collapsed position until so desired.

In an embodiment, the locking nut490may be machined as a hoop and then split into multiple segments. A spring498(e.g., a garter spring) may be provided to hold the segments of the locking nut490around the mandrel457. The spring498may resemble an O-ring, except that the spring498can be made out of wire. Such wire may be looped around the locking nut490, and the ends can be hooked together. The spring498may allow the sections of the locking nut490to open and close as the locking nut490jumps over each individual serration as it moves upwardly on the mandrel457. Thus, the spring498may allow the locking nut490to slide up the ramp of a mandrel serration and jump over to the next serration, thereby ratcheting itself up the mandrel457. The spring498can also hold the locking nut490segments together so that the locking nut490cannot back up over the serrations on the mandrel457.

The anchor assembly410may also designed to return from an expanded position to a released, collapsed position. For instance, as discussed herein with respect to the coring systems100,200, and300, 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 assembly410may 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 assembly410ofFIGS. 12-14can be released from gripping engagement with a surrounding wellbore wall by applying an upwardly directed force sufficient to allow the slips414to retract to the released and collapsed position shown inFIG. 12. In particular, the lock housing488shown inFIG. 14may be connected to the piston housing476by shear screws486. To return the anchor assembly410to a collapsed position, an axial force can be applied to the anchor assembly410sufficient to shear the shear screws486, thereby releasing the locking subassembly482. As shown inFIG. 12, a release ring499may be disposed between the upper slip housing470and the mandrel457. In one aspect, the release ring499can provide a shoulder to restrict the upper slip housing470from sliding too far downwardly with respect to the slips414in the run-in, retracted position ofFIG. 12, or after releasing the anchor assembly410to the position shown inFIG. 12. In another aspect the release ring499may be configured to allow the mandrel457to move a small distance axially before the slips414disengage from the wellbore to allow for the shear screws486to shear completely. Thus, when an axial force is applied to the mandrel457, the release ring499can allow for the slips414to maintain engagement with the wellbore to provide a counter force against which the shear screws486can shear. Therefore, the release ring499can allow the shear screws486to shear completely, which enables the slips414to collapse back into the anchor assembly410. With the anchor assembly410in the released and collapsed position ofFIG. 12, the anchor assembly410can be removed from the wellbore.

In accordance with one embodiment, the anchor assembly410ofFIGS. 12-14may be used in connection with a coring system200ofFIGS. 4-8or a coring system300ofFIGS. 9-11. It should be appreciated in view of the disclosure herein, that when connected to the anchor assembly410, a coring system200,300may be used to expand and engage the slips414against a wellbore and anchor a corresponding deflector assembly208,308in place. Optional hydraulic lines (seeFIG. 2) may be used to provide hydraulic fluid to expand the slips414.

When a core sample has been obtained, the anchor assembly410may be released by applying an upwardly directed force to retract the slips414as discussed herein. For instance, as shown inFIGS. 4-8, a collar244of a coring assembly206may engage a sleeve246of a deflector assembly208. By pulling upwardly on the coring assembly206, a corresponding upward force can be applied to the deflector assembly, which may also be connected to the mandrel447of the anchor assembly410. Such upward force, if sufficient to shear the shear screws486, may allow the slips414to retract, thereby allowing the coring assembly206, deflector assembly208, and anchor assembly410to be removed. A similar process may be used with the coring system300ofFIGS. 9-11, in which a collar344or a coring assembly306may engage a shoulder346of a deflector assembly308to exert an upward force that may release the slips414of the anchor assembly410.

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 assembly410may 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 slips414and/or the mandrel457to allow selective expansion and retraction of the slips414. Thus, the shear screws486are 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.