Cross Reference Paragraph

[0001] This application claims the benefit of U.S. Provisional Application No. 62/893582 entitled “Drilling Mast,” filed August 29, 2019, the disclosure of which is incorporated herein by reference.

Background

[0002] A wellsite may include a derrick positioned over a wellbore that is drilled in a subterranean formation. The derrick may be used to lower one or more tubulars (e.g., a drill string) into the wellbore and/or raise the one or more tubulars out of the wellbore. A rotational device, such as a top drive, is positioned within the derrick and above the wellbore. The rotational device is configured to rotate the tubulars. However, because the derrick is positioned over the wellbore, this may obstruct or prevent the use of a crane to assist with moving heavy components onto and/or off of the drill floor.

Summary

[0003] This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is 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 claimed subject matter.

[0004] A mast for a drilling rig is disclosed. The mast includes a front leg and a back leg. The front leg extends at a first angle with respect to horizontal such that a lower end of the front leg is configured to be farther away from a well center plane than an upper end of the front leg. The back leg extends at a second angle with respect to horizontal such that a lower end of the back leg is configured to be farther away from the well center plane than an upper end of the back leg. The first angle is different than the second angle. The lower end and the upper end of the front leg and the lower end and the upper end of the back leg are configured to be on a same side of the well center plane.

[0005] In another embodiment, the mast includes a first front leg and a second front leg that are slanted at a first angle with respect to horizontal such that lower ends of the first and second front legs are configured to be farther away from a well center than upper ends of the first and second front legs. The mast also includes a first back leg and a second back leg that are slanted at a second angle with respect to horizontal such that lower ends of the first and second back legs are configured to be farther away from the well center than upper ends of the first and second back legs. The first angle is greater than the second angle. The mast also includes a lower mast deck coupled to the first front leg, the second front leg, the first back leg, the second back leg, or a combination thereof. The lower mast deck is configured to be positioned above a work deck. The mast also includes a winch positioned at least partially on the lower mast deck. The mast also includes an upper mast deck coupled to the first front leg, the second front leg, the first back leg, the second back leg, or a combination thereof. The upper mast deck is positioned above the lower mast deck. The mast also includes a sheave positioned at least partially on the upper mast deck. The mast also includes a cable configured to be wrapped at least partially around the winch, to extend upward from the winch to the sheave at a third angle, to be wrapped at least partially around the sheave, and to extend downward from the sheave in substantial alignment with the well center. The third angle is less than the first angle and greater than the second angle. The portion of the cable that extends downward from the sheave is configured to have a tool coupled thereto. The mast also includes a first guide rail and a second guide rail that extend downward from the upper mast deck. The first and second guide rails are substantially parallel to and laterally- offset from the well center.

[0006] A method is also disclosed. The method includes positioning a mast at a wellsite. The mast includes a front leg and a back leg. The front leg that is slanted at a first angle with respect to horizontal such that a lower end of the front leg is configured to be farther away from a well center plane than an upper end of the front leg. The well center plane is vertical and extends through a well center. The back leg that is slanted at a second angle with respect to horizontal such that a lower end of the back leg is configured to be farther away from the well center plane than an upper end of the back leg. The first angle is different than the second angle. The lower end and the upper end of the front leg and the lower end and the upper end of the back leg are configured to be on a same side of the well center plane.

Brief Description of the Drawings

[0007] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present teachings and together with the description, serve to explain the principles of the present teachings. In the figures:

[0008] Figure 1 illustrates a perspective view of a mast, according to an embodiment.

[0009] Figure 2 illustrates a cross-sectional side view of the mast positioned on a work deck at a wellsite, according to an embodiment. [0010] Figure 3 illustrates a cross-sectional front view of the mast positioned on the work deck at the wellsite, according to an embodiment.

[0011] Figure 4 illustrates a flowchart of a method for performing a wellsite operation using the mast, according to an embodiment.

Detailed Description

[0012] Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings and figures. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to one of ordinary skill in the art that the invention may be practiced without these specific details. In other instances, well-known methods, procedures, components, circuits, and networks have not been described in detail so as not to unnecessarily obscure aspects of the embodiments.

[0013] It will also be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first object or step could be termed a second object or step, and, similarly, a second object or step could be termed a first object or step, without departing from the scope of the present disclosure. The first object or step, and the second object or step, are both, objects or steps, respectively, but they are not to be considered the same object or step.

[0014] The terminology used in the description herein is for the purpose of describing particular embodiments and is not intended to be limiting. As used in this description and the appended claims, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the term “and/or” as used herein refers to and encompasses any possible combinations of one or more of the associated listed items. It will be further understood that the terms “includes,” “including,” “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. Further, as used herein, the term “if’ may be construed to mean “when” or “upon” or “in response to determining” or “in response to detecting,” depending on the context. [0015] Figure 1 illustrates a perspective view of a mast 100, according to an embodiment. The mast 100 may include one or more legs (four are shown: 110A-110D). More particularly, the mast 100 may include one or more front legs (two are shown: 110A, 110B) and one or more back legs (two are shown: 1 IOC, 110D). The front legs 110A, 110B may be closer to a well center 122 than the back legs HOC, HOD. As used herein, the well center 122 refers to the center of a wellbore. The legs 110A-110D may include lower ends 112A- 112D and upper ends 114A-114D. The lower ends 112A-112D are configured to be positioned on and/or coupled to a work deck 120.

[0016] The mast 100 may also include a lower mast deck 130 that is positioned above the work deck 120. The lower mast deck 130 may be coupled to one or more of the legs 110A- 110D and positioned between the lower ends 112A-112D and upper ends 114A-114D thereof. The lower mast deck 130 may be or include one or more cross beams 132. For example, each cross beam 132 may be coupled to two (or more) of the legs (e.g., 110A, HOC).

[0017] A winch 134 may be positioned on and/or coupled to the lower mast deck 130. The winch 134 may be positioned at least partially between the legs 110A-110D. More particularly, the winch 134 may be positioned at least partially between the front legs 110A, HOB and the back legs HOC, HOD. The winch 134 may also or instead be positioned at least partially between the legs 110A, HOC and the legs HOB, HOD. The winch 134 may have one or more cables 136 wrapped thereabout. As described in greater detail below, the winch 134 may be configured to rotate in a first direction to reel the cable 136 in and to rotate in a second direction to let the cable 136 out.

[0018] The mast 100 may also include an upper mast deck 140 that is positioned above the lower mast deck 130 and above the winch 134. For example, the upper mast deck 140 may be positioned proximate to and/or coupled to the upper ends 114A-114D of the legs 110A- 110D.

[0019] One or more sheaves 144 may be positioned on and/or coupled to the upper mast deck 140. In another embodiment, the sheave 144 may be positioned on and/or coupled to the upper ends 114A-114D of the legs 110A-110D. The sheave 144 may be or include part of a pulley system. For example, the sheave 144 may include one or more rotating wheels with one or more grooves in the outer circumference thereof that are configured to have the cable 136 positioned therein.

[0020] As shown, the cable 136 may extend upward from the winch 134 to the sheave 144, at least partially around the sheave 144, and downward from the sheave 144. An end of the cable 136 may be configured to be coupled to a tool 150. The tool 150 may be suspended over the wellbore (e.g., in alignment with the well center 122) by the cable 136. The tool 150 may be or include a top drive, which is a mechanical device that provides torque to a drill string to drill the wellbore. In another embodiment, the tool 150 may be or include a kelly and/or a swivel. In this embodiment, torque may be transmitted from a rotary table (not shown) in the work deck 120, through a kelly drive bushing into the kelly. The kelly may be coupled to a tubular member (e.g., a drill string).

[0021] The mast 100 may also include one or more guide rails (two are shown: 160A, 160B). The guide rails 160A, 160B may be coupled to and extend downward from the upper mast deck 140 and/or the upper ends 114A, 114B of the front legs 110A, 110B. The guide rails 160A, 160B may be substantially parallel to one another. As used herein, “substantially parallel” refers to within 5° of parallel. The guide rails 160A, 160B may be substantially vertical. As used herein, “substantially vertical” refers to within 5° of vertical. The guide rails 160A, 160B may be laterally-offset from the well center 122.

[0022] The tool 150 may be coupled to the guide rails 160A, 160B. More particularly, the tool 150 may include a dolly 152 that is coupled to the guide rails 160A, 160B. As described in greater detail below, when the winch 134 rotates, the dolly 152 and the guide rails 160 A, 160B guide the movement of the tool 150 so that the direction of movement is substantially parallel to the guide rails 160A, 160B (e.g., substantially vertical). In addition, as described below, the tool 150 may transfer torque to a tubular member (e.g., a drill pipe segment or drill string). The guide rails 160A, 160B may also prevent at least a portion of the tool 150 from rotating in response to the torque transmission.

[0023] Figure 2 illustrates a cross-sectional side view of the mast 100 on the work deck 120 at the wellsite, according to an embodiment. To facilitate the following description, several reference planes are introduced. A first plane 210 is shown that is vertical and extends through the guide rails 160A, 160B, which are substantially vertical.

[0024] A second plane 212 is shown that is substantially vertical, extends through the well center 122, and/or is parallel with the first plane 210. The second plane 212 may also be referred to as a well center plane. In at least one embodiment, the front leg 110A and/or the back leg HOC may be in a plane that is substantially perpendicular (e.g., within +/- 5° of perpendicular) to the second plane 212. In at least one embodiment, the legs 110A, HOC may be in the same plane.

[0025] A third plane 214 is shown that is substantially vertical, extends through the front- most portion 156 of the structure, and/or is parallel with the first plane 210, the second plane 212, or both. The front-most portion 156 of the structure may be or include the front-most portion of the legs 110A, 110B, the upper mast deck 140, or both. In other words, the front- most portion 156 may be the point on the legs 110A-110D and/or the upper mast deck 140 that is closest to the well center 122 and/or the second plane 212.

[0026] In the side view shown in Figure 2, the front legs 110A (110B not visible in Figure 2) may be substantially parallel to one another and slanted such that the lower ends 112A (112B not visible in Figure 2) are positioned farther away from the planes 210, 212, and/or 214 than the upper ends 114A (114B not visible in Figure 2). Thus, the front legs 110A, 110B may be oriented at an angle 220 with respect to horizontal, such that the lower ends 112A, 112B are farther, in a horizontal direction, from well center 122 than the upper ends 114A, 114B. The angle 220 may be from about 80° to about 89°, about 81° to about 88°, or about 82° to about 87°.

[0027] The back legs 1 IOC (110D not visible in Figure 2) may also be substantially parallel to one another and slanted such that the lower ends 112C (112D not visible in Figure 2) are positioned farther away from the planes 210, 212, and/or 214 than the upper ends 114C (114D not visible in Figure 2). Thus, the back legs 1 IOC, 110D may be oriented at an angle 222 with respect to horizontal, such that the lower ends 112C, 112D are farther, in a horizontal direction, from well center 122 than the upper ends 114C, 114D. The angle 222 may be less than the angle 220. The angle 222 may be from about 60° to about 85°, about 65° to about 83°, or about 70° to about 80°.

[0028] In an embodiment, the legs 110A, HOC may be slanted such that the upper end 114C of the back leg HOC is positioned farther from the plane(s) 210, 212, and/or 214 than the lower end 112A of the front leg 110 A. In another embodiment, the legs 110 A, 1 IOC may be slanted such that the upper end 114C of the back leg 1 IOC is positioned closer the plane(s) 210, 212, and/or 214 than the lower end 112A of the front leg 110A. In another embodiment, the legs 110A, HOC may be slanted such that the upper end 114C of the back leg HOC is positioned (e.g., directly) above a portion of the front leg 110A.

[0029] The cable 136 (e.g., the portion between the winch 134 and the sheave 144) may also be slanted such that the portion of the cable 136 proximate to the winch 134 is positioned farther away from the planes 210, 212, and/or 214 than the portion proximate to the sheave 144. Thus, the cable 136 may be oriented at an angle 224 with respect to horizontal, such that the lower portion of the cable 136 is farther, in a horizontal direction, from the well center 122 than the upper portion of the cable 136. The angle 224 may be less than the angle 220 and greater than the angle 222. The angle 224 may be from about 70° to about 88°, about 72° to about 85°, or about 75° to about 83°. In at least one embodiment, the angle 224 may be substantially halfway between the angles 220, 222. As used herein, substantially halfway refers to within +/- 5° of halfway between. For example, if the angle 220 is 80°, and the angle 222 is 60°, then the angle 224 may be halfway between the angles 220, 222 if the angle 224 is from 65° to 75°.

[0030] Having the legs 1 lOA-110D and/or the cable 136 oriented at these angles 220, 222, 224 may allow the front-most portion 156 to be on the same side of the well center 122 as the rest (e.g., a remainder) of the legs 110A-110D, the lower mast deck 130, the winch 134, the upper mast deck 140, or a combination thereof. In other words, the entirety of the legs 110A- 110D, the lower mast deck 130, the winch 134, the upper mast deck 140, or a combination thereof may be located on the same side of the well center 122. As used herein, a “same side of the well center 122” refers to a same side of the plane 212. The second and third planes 212, 214 may be laterally-offset from one another from about 1 cm to about 1 meter, about 3 cm to about 50 cm, or about 5 cm to about 20 cm. As mentioned above, having the entirety of the legs 1 lOA-110D, the lower mast deck 130, the winch 134, and the upper mast deck 140 on one side of the plane(s) 212 and/or 214 may allow space for other equipment (e.g., a crane 180) to move objects onto and off of the work deck 120, and/or into and/out of alignment with the well center 122.

[0031] The sheave 144 may extend forward from the upper mast deck 140. For example, a front-most portion 146 of the sheave 144 may extend past the plane 214. The front-most portion 146 of the sheave 144 may extend to the plane 212 and in some embodiments may extend at least partially past the plane 212. This may allow the cable 136, which is wrapped at least partially around the sheave 144, to be aligned with the well center 122 and thereby apply a purely vertical force to the tool 150, in at least some embodiments.

[0032] Having the legs 1 lOA-110D and/or the cable 136 oriented at these angles 220, 222, 224 may also cause a majority of the upward force to be concentrated through the front legs 110A and 110B, because an angle 226 between the front legs 110A, 110B and the portion of the cable 136 between the winch 134 and the sheave 144 is similar to (e.g., within 5° of) the angle 228 between the front legs 110A, 110B and the portion of the cable 136 between the sheave 144 to the tool 150.

[0033] In addition, as shown in Figure 2, having the winch 134 located on or above the lower mast deck 130 may create space underneath for equipment 138. The equipment 138 may be positioned on the work deck 120 and under the lower mast deck 130 and the winch 134. In contrast, conventional derricks have the winch 134 located on the work deck 120, leaving little or no room for equipment 138. In an example, the equipment 138 may be or include one or more choke and kill valves and for running tubular connection equipment. [0034] Figure 3 illustrates a cross-sectional front view of the mast 100, according to an embodiment. From the front view, the front legs 110A, 110B may be slanted toward one another such that the lower ends 112A, 112B are spaced farther apart than the upper ends 114A, 114B. An angle 310 between the front legs 110A, 110B may be from about 5° to about 40°, about 10° to about 30°, or about 15° to about 25°.

[0035] In addition, the mast 100 may include one or more slanted support members (two are shown: 320A, 320B). The slanted support members 320A, 320B may be coupled to one or more of the legs 1 lOA-110D, the lower mast deck 130, and/or the cross beams 132. In the example, shown, the slanted support member 320A is coupled to the lower mast deck 130 and to the leg 110A, and the slanted support member 320B is coupled to the lower mast deck 130 and to the leg 110B. The slanted support members 320A, 320B may be oriented at angles 322A, 322B that are symmetrical (e.g., mirror images) to one another. The angles 322A, 322B may be from about 40° to about 75°, about 45° to about 70°, or about 50° to about 65°. The slanted support members 320A, 320B may help direct the forces from the winch 134 into the front legs 110A, 110b so that the compression force between the sheave 144 and the winch 134 will be through the front legs 110A, 110B.

[0036] Figure 4 illustrates a flowchart of a method 400 for performing a wellsite operation using the mast 100, according to an embodiment. An illustrative order of the method 400 is described below; however, it will be appreciated that one or more portions of the method 400 may be performed in a different order, repeated, or omitted.

[0037] The method 400 may include constructing or positioning the mast 100 at a wellsite, as at 402. In at least one embodiment, positioning the mast 100 may include constructing the mast 100 from the various components (e.g., the legs 110A-110D, the decks 130, 140, etc.). The mast 100 may be positioned on one side of the plane 212 through the well center 122, as described above.

[0038] The method 400 may also include actuating the winch 134 to raise the tool 150, as at 404. This may cause the winch 134 to rotate in the first direction, which may reel in the cable 136. The dolly 152 and the guide rails 160A, 160B may guide the movement of the tool 150 so that the direction of movement is substantially parallel to the guide rails 160A, 160B (e.g., vertically upward).

[0039] The method 400 may also include coupling the tool 150 to a first tubular member 170, as at 406. An example of this is shown in Figure 2. More particularly, the tool 150 may be coupled to an upper end of the first tubular member 170. In one example, the first tubular member 170 may be or include a single tubular member. In another example, the first tubular member 170 may be or include two or more tubular members that are coupled together (i.e., a stand). In an example, the term “tubular member” may refer to one or more drill pipe segments, one or more liner segments, one or more casing segments, or the like.

[0040] The method 400 may also include coupling the first tubular member 170 to a second tubular member 172 to form a tubular string (e.g., a drill string) 174, as at 408. An example of this is shown in Figure 2. More particularly, a lower end of the first tubular member 170 may be coupled to an upper end of the second tubular member 172. The second tubular member 172 may be positioned at least partially within the wellbore.

[0041] The method 400 may also include rotating the tubular string 174 using the tool 150, as at 410. The dolly 152 and the guide rails 160A, 160B may prevent the tool 150 and/or the tubular string 174 from moving laterally while the tool 150 rotates the tubular string 174. In addition, the dolly 152 and the guide rails 160A, 160B may prevent the at least a portion of the tool 150 from rotating while the tool 150 rotates the tubular string 174, thereby transmitting torque from the tool 150 to the tubular string 174, to rotate the tubular string 174. [0042] The method 400 may also include actuating the winch 134 to lower the tool 150 and the tubular string 174, as at 412. In at least one embodiment, this may occur simultaneously with the tool 150 rotating the tubular string 174. Actuating the winch 134 may cause the winch 134 to rotate in the second direction, which may let out the cable 136. The dolly 152 and the guide rails 160A, 160B may guide the movement of the tool 150 so that the direction of movement is substantially parallel to the guide rails 160A, 160B (e.g., vertically downward). In at least one embodiment, the tubular string 174 may have a drill bit coupled to a lower end thereof, and the rotation of the tubular string 174 combined with the weight and/or downward movement of the tubular string 174 may cause the drill bit to drill farther into the subterranean formation, thereby increasing the length/depth of the wellbore.

[0043] The method 400 may also include setting a slips device 176 to grip the tubular string 174, as at 414. An example of this is shown in Figure 2. More particularly, once the tool 150 and the tubular string 174 have been lowered, the slips device 176 may be set to grip the first tubular member 170 and to support the weight of the tubular string 174.

[0044] The method 400 may also include decoupling the tool 150 from the first tubular member 170, as at 416. More particularly, the tool 150 may be decoupled to the upper end of the first tubular member 170 when the slips device 176 is gripping the first tubular member 170 and supporting the weight of the tubular string 174. The method 400 may then loop back around to 404 and repeat to increase the length of the drill string 174 and/or increase the depth of the wellbore.

[0045] In at least one embodiment, the crane 180 may operate simultaneously with one or more portions 402-416 of the method 400. The crane 180 may operate on one side of the plane 212, while the mast 100 operates on the other side of the plane 212. Thus, the mast 100 may not interfere with the operation of the crane 180, and vice versa. As mentioned above, the operation of the crane 180 may include moving objects onto and off of the work deck 120, and/or into and/out of alignment with the well center 122. In one embodiment, the crane 180 may assist the mast 100 with lowering the tubular string 174 into the wellbore and/or raising the tubular string 174 out of the wellbore.

[0046] As used herein, the terms “inner” and “outer”; “up” and “down”; “upper” and “lower”; “upward” and “downward”; “upstream” and “downstream”; “above” and “below”; “inward” and “outward”; and other like terms as used herein refer to relative positions to one another and are not intended to denote a particular direction or spatial orientation. The terms “couple,” “coupled,” “connect,” “connection,” “connected,” “in connection with,” and “connecting” refer to “in direct connection with” or “in connection with via one or more intermediate elements or members.”

[0047] The foregoing description, for purpose of explanation, has been described with reference to specific embodiments. However, the illustrative discussions above are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in view of the above teachings. Moreover, the order in which the elements of the methods are illustrated and described may be re-arranged, and/or two or more elements may occur simultaneously. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated.