Patent Application
20200392795
Embodiments of the present disclosure generally relate to earth-boring (e.g., downhole) tools. In particular, to earth-boring tools, apparatus, and methods used to insert casings within a wellbore in a subterranean formation.
The drilling of wells for oil and gas production conventionally employs longitudinally extending sections or so-called “strings” of drill pipe to which, at one end, is secured a drill bit of a larger diameter. After a selected portion of the borehole has been drilled, the borehole is usually lined or cased with a string or section of casing. Such a casing or liner usually exhibits a larger diameter than the drill pipe and a smaller diameter than the drill bit. Therefore, drilling and casing according to the conventional process typically requires sequentially drilling the borehole using drill string with a drill bit attached thereto, removing the drill string and drill bit from the borehole, and disposing casing into the borehole. Further, often after a section of the borehole is lined with casing, which is usually cemented into place, additional drilling beyond the end of the casing may be desired.
Unfortunately, sequential drilling and casing may be time consuming because, as may be appreciated, at the considerable depths reached during oil and gas production, the time required to implement complex retrieval procedures to recover the drill string before running casing may be considerable. Such operations may be costly as well, since, for example, the beginning of profitable production can be greatly delayed. Moreover, control of the well may be difficult during the period of time that the drill pipe is being removed and the casing is being disposed into the borehole. Thus, in some instances, it is known to combine the drilling and casing processes into one run by attaching a “casing bit” to the end of a casing string and drilling with the casing string itself instead of with a conventional drill string. Nonetheless, there are situations in which a casing string may become stuck in a subterranean formation before reaching the intended depth within the formation.
Some embodiments may include a downhole tool assembly. The downhole tool assembly may include a first casing section and a second casing section. The first and second casing sections may be configured to be inserted into a borehole. The downhole tool may also include an earth-boring tool. The earth-boring tool may include at least one blade. The earth-boring tool may be coupled between the first casing section and the second casing section. The at least one blade may be configured to remove material from a downhole formation.
Another embodiment may include a method of securing a casing into a formation. The method may include inserting the casing string into an earth formation. The method may further include rotating the casing string. The method may also include removing an obstruction in a wellbore with an earth-boring tool coupled between at least two segments of casing in the casing string by rotation of the casing string. The method may further include cementing the casing string and the earth-boring tool in place within the wellbore.
A further embodiment may include a method of manufacturing an earth-boring tool. The method may include forming a body of the earth-boring tool. The body may include at least one blade, a bore, and threads. The at least one blade may extend radially from the body. The bore may extend through the body along a longitudinal axis of the body. The threads may be formed on both a first end and a second end of the body. The threads may be configured to couple the body between segments of casing in a casing string.
While the specification concludes with claims particularly pointing out and distinctly claiming embodiments of the present disclosure, the advantages of embodiments of the disclosure may be more readily ascertained from the following description of embodiments of the disclosure when read in conjunction with the accompanying drawings in which:
The illustrations presented herein are not meant to be actual views of any particular earth-boring tool or component thereof, but are merely idealized representations employed to describe illustrative embodiments. The drawings are not necessarily to scale.
As used herein, relational terms, such as “first,” “second,” “top,” “bottom,” etc., are generally used for clarity and convenience in understanding the disclosure and accompanying drawings and do not connote or depend on any specific preference, orientation, or order, except where the context clearly indicates otherwise.
As used herein, the term “and/or” means and includes any and all combinations of one or more of the associated listed items.
As used herein, the term “substantially” or “about” in reference to a given parameter means and includes to a degree that one skilled in the art would understand that the given parameter, property, or condition is met with a small degree of variance, such as within acceptable manufacturing tolerances. For example, a parameter that is substantially met may be at least about 90% met, at least about 95% met, at least about 99% met, or even 100% met.
As used herein, the terms “behind” and “ahead” when used in reference to a component of a drill string or casing string refer to a direction relative to the motion of the component of the drill string. For example, if the component is moving into a borehole a bottom of the borehole is ahead of the component and the surface and the drill rig are behind the component.
Some approaches have been developed to address the difficulties associated with conventional drilling and casing operations. Of initial interest is an apparatus, which is known as a “casing shoe,” that has been used in conventional wellbore casing operations. Casing shoes are devices that are attached to the end of a casing string and are able to drill through modest obstructions within a borehole that has been previously drilled while the wellbore casing is advanced into the wellbore. In addition, the casing shoe may include an inner section manufactured from a material that is drillable by rotary drill bits. Accordingly, when cemented into place, casing shoes usually pose no difficulty to a subsequent drill bit. For instance, U.S. Pat. No. 6,062,326 to Strong et al. discloses a casing shoe in which the central portion thereof may be configured to be drilled through. In addition, U.S. Pat. No. 6,062,326 to Strong et al. discloses a casing shoe that may include diamond cutters over the entire face thereof, if it is not desired to drill therethrough.
As a further extension of the casing shoe concept, in order to address the problems with sequential drilling and casing, drilling with casing is gaining popularity as a method for initially drilling a borehole, wherein the casing is used as the drilling conduit and, after drilling, the casing is cemented into and remains within the wellbore to act as the wellbore casing. Drilling with casing employs a drill bit that is configured for attachment to the casing string instead of a drill string, so that the drill bit functions not only to drill the earth formation, but also to guide the casing into the wellbore. This may be advantageous because the casing is disposed into the borehole as it is formed by the drill bit, and therefore eliminates the necessity of retrieving the drill string and drill bit after reaching a target depth where cementing is desired. Such drill bits that are configured for attachment to a casing string are referred to hereinafter as “drill shoes.”
As used herein, the terms “earth-boring casing shoes” and “casing shoes” mean and include any device that is configured for attachment to an end of a section of casing and used for drilling a wellbore or for guiding casing through a previously drilled wellbore as the section of casing to which the device is attached is advanced into a subterranean formation. Casing shoes may be used to guide casing through a wellbore and ensure that the wellbore diameter remains as drilled (i.e., has not decreased as sometimes occurs in reactive or sloughing formations).
In some environments, the formation material may be unstable around the borehole. For example, the formation may include flowable material such as tar or loose material such as sand. Unstable formation material may lead to cave-ins, borehole swelling, and other obstructions. If the obstructions occur behind the earth-boring casing shoes, the obstruction can restrict movement of the casing. An unresolved restriction may lead to a stuck casing. Stuck casings can result in multiple days of down time while the stuck casing is removed.
In accordance with embodiments of the present disclosure, a wellbore casing reamer tool is provided. The wellbore casing reamer tool may be coupled between two sections of casing. The wellbore casing reamer tool may include blades having cutting elements mounted thereon. The wellbore casing reamer tool may be used when drilling with casing, or when guiding casing into a previously drilled wellbore. The wellbore casing tool may be useful when casing a wellbore that extends through a flowable material in a subterranean formation.
The casing string 102 may be formed from multiple segments 108 (e.g., sections, pieces, etc.) of casing. Each segment 108 of casing may be at least one casing pipe. Casing pipe may be in lengths between about 10 feet (3.048 m) and about 60 feet (18.288 m), such as between about 30 feet (9.144 m) and about 50 feet (15.24 m), or between about 40 feet (12.192 m) and about 42 feet (12.8016 m). The outside diameter of casing pipe may range from about 4.5 inches (11.43 cm) to about 20 inches (50.80 cm).
In some embodiments, the segments 108 of casing may be coupled together to form the casing string 102. For example, the segments 108 of casing may be coupled together with a threaded connection, which may conform to industry standards (e.g., American Petroleum Institute (API) standards, etc.). In some embodiments, the each segment 108 may include complementary threads on each end of the segment 108. For example, a first end of each segment 108 may include female threads and a second end of each segment 108 may include complementary male threads such that each segment 108 may be threaded into the adjoining segment 108.
In some embodiments, each segment 108 may be coupled with a coupler. For example, each end of each segment 108 may have identical threads, such as threads that are the same size, pitch, and orientation (e.g., male or female). The coupler may be a short segment of threaded pipe. The threads on the coupler may be complementary to the threads on each end of the segments 108, such that the coupler may be threaded into adjoining segments 108 coupling the segments 108 together. For example, the segments 108 may have substantially identical male threads on each end of each segment 108. The coupler may be a length of pipe that is substantially shorter than the segments 108 that has substantially identical (e.g., same size, pitch, and orientation) female threads on each end of the coupler that are complementary to the male threads on each end of each segment 108. The male threads of each segment 108 may be threaded into the female threads on the coupler coupling the adjacent segments 108 to each other through the coupler. In some embodiments, the segments 108 may have substantially identical female threads and the coupler may have substantially identical complementary male threads.
The casing string 102 may include one or more mid-string earth-boring tools 110 positioned in a middle portion of the casing string 102. One or more segments 108 of casing may be between each mid-string earth-boring tool 110 and between at least one of the mid-string earth-boring tool 110 and the casing shoe 106. The mid-string earth-boring tools 110 may have an outside diameter 112 at least as large as an outside diameter 114 of the casing string 102. In some embodiments, the mid-string earth-boring tools 110 may have an outside diameter 112 that is larger than an outside diameter 114 of the casing string 102. In some embodiments, the outside diameter 112 of the mid-string earth-boring tools 110 may be smaller than an inside diameter 116 of the borehole 104, such that the mid-string earth-boring tools 110 are not configured to enlarge the borehole 104 beyond the original inside diameter 116 of the borehole 104, unless the borehole has collapsed after drilling, for example, due to an unstable formation or materials or the presence of flowable material.
The outside diameter 112 of the mid-string earth-boring tools 110 may be greater than the outside diameter 114 of the casing string 102, such as between the outside diameter 114 of the casing string 102 and the inside diameter 116 of the borehole 104, between the outside diameter 114 of the casing string 102 and about 150% of the diameter 114 of the casing string 102, between about 105% of the diameter 114 of the casing string 102 and about 125% of the diameter 114 of the casing string 102, or between about 110% of the diameter 114 of the casing string 102 and about 120% of the diameter 114 of the casing string 102.
The mid-string earth-boring tool 110 may be configured to couple two segments 108 of the casing string 102 together. For example, the mid-string earth-boring tool 110 may include complementary threads to the adjacent segments 108 of the casing string 102. In some embodiments, the mid-string earth-boring tool 110 may be configured to join the two segments 108 of the casing string 102 in place of a coupler. For example, the two segments 108 of the casing string 102 may have identical threads (e.g., same size, pitch, and orientation) on each end of each segment 108. The mid-string earth-boring tool 110 may have complementary threads to the threads on the ends of each segment 108. One end of each of the two segments 108 may then be threaded into the mid-string earth-boring tool 110 coupling the two segments 108 through the mid-string earth-boring tool 110. In some embodiments, the adjacent segments 108 of the casing string 102 may have identical male threads and the mid-string earth-boring tool 110 may have complementary female threads. In some embodiments, the adjacent segments 108 of the casing string 102 may have identical female threads and the mid-string earth-boring tool 110 may have complementary male threads.
In another example, the mid-string earth-boring tool 110 may couple to the adjoining segments 108 in the same manner that the segments 108 would couple to one another if the mid-string earth-boring tool 110 were not there. In other words, the mid-string earth-boring tool 110 may act as another segment 108 in the casing string 102. For example, the segments 108 may have complementary threads on each end of each segment 108. The mid-string earth-boring tool 110 may have similar complementary threads on each end of the mid-string earth-boring tool 110. The mid-string earth-boring tool 110 may be inserted between the two segments 108 coupling the two segments 108 in the same manner that the segments 108 would have coupled to each other. In another example, each segment 108 may be coupled with a coupler. Each end of each segment 108 may have identical threads, such as threads that are the same size, pitch, and orientation. The mid-string earth-boring tool 110 may have the same identical threads to the ends of each segment 108. The coupler may be a short segment of threaded pipe. The threads on the coupler may be complementary to the threads on each end of the segments 108 and the mid-string earth-boring tool, such that the coupler may be threaded onto the adjoining segments 108 and the mid-string earth-boring tool 110 coupling the segments 108 together through the mid-string earth-boring tool 110. In some embodiments, the mid-string earth-boring tool 110 may be coupled to the coupler and/or segments 108 through another coupling process, such as welding, soldering, brazing, pressing, etc. In some embodiments, the mid-string earth-boring tool 110 may be coupled through a combination of processes. For example, the mid-string earth-boring tool 110 may be coupled to the coupler and/or segments 108 with a threaded connection. Once the threaded connection is completed (e.g., tight, bottomed out, etc.) the connection may be welded, soldered, brazed, pinned, etc. The pin, weld, solder, or braze may substantially prevent the threaded connection from slipping, backing out, un-threading, etc.
In some embodiments, multiple mid-string earth-boring tools 110 may be inserted into the casing string 102. For example, the casing string 102 may include more than two mid-string earth-boring tools 110, such as between two mid-string earth-boring tools 110 and ten mid-string earth-boring tools 110, between three mid-string earth-boring tools 110 and five mid-string earth-boring tools, or about 4 mid-string earth-boring tools. In some embodiments, the mid-string earth-boring tools 110 may be inserted at uniform intervals (e.g., a distance between each of the mid-string earth-boring tools is the same). In other embodiments, the intervals between the mid-string earth-boring tools may vary. For example, the make-up of the formation may dictate the intervals that are used. In some embodiments, a mid-string earth-boring tool 110 may be inserted between each segment 108.
Once the casing string 102 reaches a desired location, the casing string may be left in the borehole 104. The mid-string earth-boring tool 110 may remain in the borehole 104 along with the casing string 102. In some embodiments, the casing string 102 may be secured within the borehole 104. For example, the casing string 102 may be secured in the borehole 104 with cement, backfill, or other known techniques. In some embodiments, only a portion of the casing string 102 may be secured. For example, cement may be used to provide zonal isolation for the casing string 102.
The at least one blade 202 on the mid-string earth-boring tool 110 may be configured to clear an obstruction behind the casing shoe 106 as the casing string 102 advances through the borehole 104. The at least one blade 202 may include hard elements 204 on an exterior surface of the at least one blade 202. In some embodiments, the hard elements 204 may include deposits of hardfacing material. Such hardfacing material may comprise, for example, hard and abrasive particles (e.g., diamond, boron nitride, silicon carbide, carbides or borides of titanium, tungsten, or tantalum, etc.) embedded within a metal or metal alloy matrix material (e.g., an iron-based, cobalt-based, or nickel-based metal alloy). In some embodiments, the hard elements 204 may include cutting structures such as polycrystalline diamond compact (PDC) cutting elements secured to the at least one blade 202. The hard elements 204 may be configured to contact the obstruction breaking up, cutting, wearing, and/or otherwise clearing away the obstruction as the at least one blade 202 rotates through the obstruction.
The mid-string earth-boring tool 110 may include so called “junk slots” 206 between the blades 202. The junk slots 206 may be configured to provide a path between the mid-string earth-boring tool 110 and the wall of the borehole 104 such that hydraulic drilling fluid and other material carried therein may cross the mid-string earth-boring tool when flowing through the annulus between the casing string 102 and the wall of the borehole 104. For example, fluid present downhole such as drilling mud may pass through the junk slots 206 to exit the borehole 104. Debris removed from obstructions may also pass through the junk slots 206. For example, the debris from the obstructions may be carried to the surface passing through the junk slots 206 with the drilling mud. In some embodiments, when the casing string 102 is in position, the junk slots 206 may allow cement to pass through the junk slots to secure portions of the casing string 102 in place within the borehole 104.
The mid-string earth-boring tool 110 may have a bore 312 that is substantially free of obstruction. The bore 312 may be substantially annular (e.g., ring shaped, circular, etc.). The bore 312 may extend through the entire mid-string earth-boring tool 110 defining a path through the center of the mid-string earth-boring tool 110. In some embodiments, the bore 312 may have an inner diameter 314 that is substantially the same as an inner diameter of the adjoining segments 108 of the casing string 102. In some embodiments, the inner diameter 314 of the bore 312 may be larger than the inner diameter of the adjoining segments 108. For example, the bore 312 may be substantially the same size as the outer diameter 114 of the adjoining segments 108 and configured to receive threaded ends of the adjoining segments 108 within the bore 312. In some embodiments, the inner diameter 314 of the bore 312 may be smaller than the inner diameter of the adjoining segments 108. For example, the mid-string earth-boring tool 110 may be configured to thread into the adjoining segments 108 such that the inner diameter of the adjoining segments 108 may be substantially the same as an outer diameter 316 of the body 300 of the mid-string earth-boring tool 110.
In some embodiments, the blades 202 may be arranged such that the blades are substantially parallel to the casing string 102. In other embodiments, the blades 202 may have other profiles, shapes, layouts, etc. For example,
In some embodiments, mid-string earth-boring tools 110 with different blade designs may be used on the same casing string 102. For example, different blade designs may be better suited for some obstacles than others. Therefore, in a drilling operation an operator may choose different mid-string earth-boring tools 110 for different portions of the casing string 102 based on the type of obstacle that is expected in each region.
Embodiments of the present disclosure may reduce or even eliminate stuck casing events. A stuck casing string can require multiple days to retrieve, which can have extensive adverse financial consequences. Avoiding stuck casing events may result in significant cost savings during a drilling operation. Additionally, the drilling operation may be more efficient when operations are not stopped to retrieve a stuck pipe. The increased efficiency may result in creating a productive well that will begin generating revenue in a shorter period of time.
The embodiments of the disclosure described above and illustrated in the accompanying drawing figures do not limit the scope of the invention, since these embodiments are merely examples of embodiments of the invention, which is defined by the appended claims and their legal equivalents. Any equivalent embodiments are intended to be within the scope of this disclosure. Indeed, various modifications of the present disclosure, in addition to those shown and described herein, such as alternative useful combinations of the elements described, may become apparent to those skilled in the art from the description. Such modifications and embodiments are also intended to fall within the scope of the appended claims and their legal equivalents.
This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application Ser. No. 62/862,370, filed Jun. 17, 2019, the disclosure of which is hereby incorporated herein in its entirety by this reference.
| Number | Date | Country | |
|---|---|---|---|
| 62862370 | Jun 2019 | US |
