Embodiments of the invention described herein pertain to the field of oil and gas well completion. More particularly, but not by way of limitation, one or more embodiments of the invention enable a casing string torque transfer and suspension system and method for mandrel casing hangers.
Fluid, such as natural gas, oil or water, is often located in underground formations. In oil and gas wells, completion is the process of making the underground well ready for production or injection. The completion process conventionally involves preparing the bottom of the hole to the required specifications, running in and cementing the casing, running in the production tubing and its associated downhole tools, as well as perforating and stimulating as required.
Once a well has been drilled, the first step is to case the hole. Casing ensures that the well does not close in on itself once the drilling fluids are removed. Casing consists of steel pipe that is joined together to make a long, hollow tube. Typically, multiple approximately thirty-foot lengths of pipe are threaded together to create the casing string, which can be thousands of feet long depending on well depth, casing size and whether the casing is an outermost casing string or an intermediate casing string. The threaded connections are often referred to as collars. When assembled, the casing string weights hundreds of thousands of pounds and is lowered into the well by a drilling rig.
The casing string also includes a casing hanger. During casing installation, the casing string is lowered until the casing hanger is seated on a shoulder in the wellhead. Mandrel type casing hangers are often preferred to the alternative, which are known as slip-type casing hangers. The mandrel-type casing hanger suspends the casing from the wellhead, using the weight of the casing string extending below the mandrel casing hanger to secure the mandrel casing hanger on a shoulder of the wellhead housing. Once the casing string is in place suspended from the wellhead, the next step in well completion involves cementing the well. Cementing involves pumping cement slurry into the well to fill in the space between the casing and the sides of the drilled well, or to fill the space between an intermediate casing and the casing immediately outwards. Cementing seals the annulus after a casing string has been run into the wellbore and binds the casing to the well bore or formation, and to subsequent casing, to provide support to the completed well.
In order to lower and cement the casing string, a running tool is typically used to assist in suspending and reciprocating the casing string as required. The running tool consists of a cylindrical body that threads to the mandrel casing hanger on a bottom side of the running tool and is attached to manipulation casing on a top side of the running tool. The well casing to be run into the wellbore is threaded onto the bottom of the mandrel casing hanger. All of the threaded connections in the casing string are conventionally tightened by a right-handed rotation, and loosened with a left-handed rotation. Once the casing mandrel is lowered and seated in place on the wellhead housing, the running tool must be separated by a left-hand rotation. One problem that arises with this technique, however, is the left-handed rotation of the casing string to disengage the running tool must be accomplished with minimal torque due to concerns of backing off (unthreading the other connections in the casing string).
Another problem is the current running tool systems do not allow rotation of the casing string about its longitudinal axis. It is often beneficial to rotate a casing string while it is being run into the wellbore or during cementing. For example, during cementing, rotation of the casing string can ensure a casing bond of higher quality by improving the distribution of cement around the outer diameter of the casing. In another example, in horizontal wells, the casing must pass through a radius (or turn), and rotation of the casing is desirable when the casing is passing through the radius to keep the casing from sticking. However, conventional casing strings cannot be rotated with a right-hand rotation without applying too much torque to the running tool's threaded connection to the mandrel. Further, conventional casing strings cannot be sufficiently rotated to the left without concerns over prematurely detaching the running tool or unthreading the sections of casing that form the casing string.
It has been proposed to use a complex system of slots on the flange of a mandrel casing hanger, in combination with retractable dogs on a running tool, in order to provide a connection between the running tool and mandrel casing hanger that would permit rotation of the casing string. However, the proposed system has proved impractical because it requires an unmanageable amount of springs, pins and/or other small parts that must be assembled at the wellsite, and in addition, it is not readily adjustable for various casing sizes.
As is apparent from the above, current running tools for mandrel casing hangers do not adequately provide for both rotation and reciprocation of the casing string. Therefore, there is a need for an improved casing string torque transfer and suspension system and method for mandrel casing hangers.
One or more embodiments of the invention enable a casing string torque transfer and suspension system and method for mandrel casing hangers.
A casing string torque transfer and suspension system and method for mandrel casing hangers is described. An illustrative embodiment of a casing string torque transfer and suspension system includes a pair of rotary drive rings secured circumferentially around a casing string running tool, the pair of rotary drive rings including a drive ring member coupled above a torque transfer ring member, a plurality of cushioning members positioned in a space between the drive ring member and the torque transfer ring member, the drive ring member secured to the casing string running tool, and the torque transfer ring member including a series of sloping teeth, each sloping tooth removably interspersed within fluid bypass flutes of a mandrel casing hanger. In some embodiments, the pair of rotary drive rings is rotatable between a torque transfer position, wherein when the rotary drive rings are rotated in a first direction, the pair of rotary drive rings transfer torque from the casing string running tool to a casing string secured below the mandrel casing hanger, and a retracted position, wherein when the casing string running tool is rotated in a second direction the rotary drive rings retract to separate the casing string running tool from the mandrel casing hanger. In certain embodiments, in the retracted position the plurality of cushioning members compress and the series of sloping teeth disengage from the fluid bypass flutes. In some embodiments, a sloped side of each sloping tooth of the series of sloping teeth slides along a beveled corner of a particular fluid bypass flute of the fluid bypass flutes as the series of sloping teeth disengage from the fluid bypass flutes to actuate into the retracted position. In certain embodiments, the casing string running tool is threadably connected to the mandrel casing hanger and a casing string is suspended below the mandrel casing hanger. In some embodiments, the mandrel casing hanger seats on a shoulder of a wellhead housing at a surface of a downhole well, and further including a casing string threaded to the mandrel casing hanger, the casing string extending into the downhole well. In certain embodiments, each sloping tooth further includes an axially extending edge parallel to a first wall of a particular fluid bypass flute in which the sloping tooth is removably interspersed, and a sloping edge opposite the axially extending edge, the sloping edge spaced from a second wall of the particular fluid bypass flute, the second wall parallel to the first wall and the sloping edge extending at about a forty-five degree angle from the second wall. In some embodiments, a top corner of the second wall is beveled at about same angle as the sloping edge. In certain embodiments, rotating the rotary drive rings in a first direction abuts the axially extending edge against the first wall to transfer torque from the casing string running tool to a casing string secured below the mandrel casing hanger, and wherein rotating the rotary drive rings in a second direction slides the sloping edge along the second wall as the rotary drive rings retract to disengage the casing string running tool from the mandrel casing hanger. In some embodiments, the pair of rotary drive rings transfer an axial load to a casing string secured below the mandrel casing hanger.
An illustrative embodiment of a casing string torque transfer and suspension system includes a running tool threadable to a mandrel casing hanger, the mandrel casing hanger including a casing string threaded to the mandrel casing hanger and extending below the mandrel casing hanger, a plurality of flutes dispersed circumferentially around a flange of the mandrel casing hanger, and a pair of rotary drive rings extending around an outer diameter of one of the running tool, the mandrel casing hanger or a combination thereof, the pair of rotary drive rings including an upper drive ring member pinned to the outer diameter of the running tool, and a lower driven ring member interlocked to the upper ring member below the upper ring member, the lower driven ring member including a set of protruding portions, each protruding portion of the set of protruding portions extending into one of the flutes when the running tool is threaded to the mandrel casing hanger. In some embodiments, each flute includes a pair of axially extending walls, and each protruding portion further includes an axially extending side parallel to a first axially extending wall of the pair of axially extending walls, the axially extending side abuttable against the first axially extending wall such that rotation of the running tool in a first direction transfers torque through the abutment and rotates the casing string, and a sloping side opposite the axially extending side and spaced from a second axially extending wall of the pair of axially extending walls, such that rotation of the running tool in a second direction disengages the running tool from the mandrel casing hanger. In some embodiments, the casing string torque transfer and suspension system includes a bevel on a top corner of the second axially extending wall, wherein during rotation of the running tool in the second direction, the sloping side slides along the bevel as the lower driven ring member moves upward. In certain embodiments, the first direction is a right-handed rotation and the second direction is a left-handed rotation when viewed from above the casing string. In some embodiments, the flange of the mandrel casing hanger is seatable on a wellhead housing shoulder. In certain embodiments, each flute of the plurality of flutes is a fluid bypass flute. In some embodiments, the casing string torque transfer and suspension system further includes a first set of rectangular teeth extending downward from the upper drive ring member, the first set of rectangular teeth interlocking with a second set of rectangular teeth that extend upward from the lower driven ring member, and a plurality of cushioning members extending axially between the upper drive ring member and the lower driven ring member, the plurality of cushioning members dispersed circumferentially around the pair of rotary drive rings. In certain embodiments, each cushioning member of the plurality of cushioning members extends from a rectangular tooth of the lower driven ring member into a trough of the first set of rectangular teeth of the upper drive ring member.
An illustrative embodiment of a torque transfer and suspension tool for a mandrel type casing hanger suspending a casing string into a downhole well includes a pair of rotary drive rings secured around an outer diameter of a running tool, a torque transfer ring of the pair of rotary drive rings including a series of sloping teeth that removably couple to the mandrel type casing hanger, the pair of rotary drive rings transferring torque to the casing string to rotate the casing string in a right-handed direction during one of running of the casing string, cementing of the casing string or a combination thereof, and the pair of rotary drive rings transferring axial loads from the running tool to the mandrel type casing hanger and the casing string when the running tool is threaded to the mandrel type casing hanger. In some embodiments, rotation of the pair of rotary drive rings in a left-handed direction retracts the rotary drive rings as the torque transfer and suspension tool separates from the mandrel type casing hanger.
An illustrative embodiment of a method of rotating a casing string suspended in a downhole well includes securing a pair of rotary drive rings around an outer diameter of a running tool such that slanted teeth of the rotary drive rings extend into fluid bypass flutes of a mandrel casing hanger when the mandrel casing hanger is threaded to the running tool, cushioning a space between the pair or rotary drive rings with a compressible member, reciprocating the casing string by using the pair of rotary drive rings to transfer axial loads from the running tool to a casing string suspended below the mandrel casing hanger when the mandrel casing hanger is threaded to the running tool, abutting a vertical side of each slanted tooth of the slanted teeth of the rotary drive rings against the fluid bypass flutes to transfer torque from the running tool to the mandrel casing hanger and rotate the casing string in a right-handed direction, and retracting the pair of rotary drive rings by sliding a slanted side of the slanted teeth upward and away from the fluid bypass flutes to separate the running tool from the mandrel casing hanger when the running tool is rotated in a left-handed direction. In some embodiments, an upper ring of the pair of rotary drive rings is secured to the running tool, and a lower ring of the pair of rotary drive rings includes the slanted teeth. In certain embodiments, the space between the pair of rotary drive rings is below the upper ring and above the lower ring, and a plurality of the compressible members extend between them, the plurality of compressible members dispersed around the pair of rotary drive rings. In some embodiments, the plurality of compressible members are compressed during rotation in the left-handed direction. In certain embodiments, the casing string is rotated in the right-handed direction during cementing of the casing string.
In further embodiments, features from specific embodiments may be combined with features from other embodiments. For example, features from one embodiment may be combined with features from any of the other embodiments. In further embodiments, additional features may be added to the specific embodiments described herein.
Advantages of the present invention may become apparent to those skilled in the art with the benefit of the following detailed description and upon reference to the accompanying drawings in which:
While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and may herein be described in detail. The drawings may not be to scale. It should be understood, however, that the embodiments described herein and shown in the drawings are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the scope of the present invention as defined by the appended claims.
A casing string torque transfer and suspension system and method for mandrel casing hangers is described. In the following exemplary description, numerous specific details are set forth in order to provide a more thorough understanding of embodiments of the invention. It will be apparent, however, to an artisan of ordinary skill that the present invention may be practiced without incorporating all aspects of the specific details described herein. In other instances, specific features, quantities, or measurements well known to those of ordinary skill in the art have not been described in detail so as not to obscure the invention. Readers should note that although examples of the invention are set forth herein, the claims, and the full scope of any equivalents, are what define the metes and bounds of the invention.
As used in this specification and the appended claims, the singular forms “a”, “an” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to a casing string includes one or more casing strings.
As used in this specification and the appended claims, “coupled” refers to either a direct connection or an indirect connection (e.g., at least one intervening connection) between one or more objects or components. The phrase “directly attached” means a direct connection between objects or components.
As used herein the terms “axial”, “axially”, “longitudinal” and “longitudinally” refer interchangeably to the direction extending along the length of the casing string.
As used in this specification and the appended claims, “right-handed” or “right-hand” refers to rotation in a clockwise direction when viewed from above the casing string.
As used in this specification and the appended claims, “left-handed” or “left-hand” refers to rotation in a counterclockwise direction when viewed from above the casing string.
For ease of description and so as not to obscure the invention, illustrative embodiments are primarily described in terms of a casing string suspended from a wellhead and extending into an oil and/or gas downhole well. However, the invention is not so limited. Illustrative embodiments may be equally applied to any casing string suspended by a mandrel-type casing hanger where rotation of the suspended casing string is desired in addition to reciprocation of the casing string.
Illustrative embodiments provide a pair of drive rings that transfer torque between a running tool and a casing string to rotate the casing string in a right-handed direction without over-torquing the threaded connection between the running tool and a mandrel casing hanger. The running tool may also carry the axial loads of the casing string and mandrel when the drive rings are engaged in the mandrel's fluid bypass flutes. The pair of drive rings may be secured around the outer diameter of the running tool body and may permit disengagement of the running tool from the mandrel casing hanger with a low-torque, left-handed rotation that may not unthread any other connections in the casing string. The pair of drive rings may include a set of asymmetrical, slanted teeth that extend into flutes of the mandrel casing hanger. Left-handed rotation of the running tool may cause the slanted teeth to slide upwards out of the flutes similar to a pawl mechanism. A cushioning member, such as compressible springs, arranged between each drive ring of the pair of drive rings may provide a torque transmission connection between the pair of drive rings and permit compression of the pair of drive rings as the running tool is disengaged from the mandrel casing hanger.
Illustrative embodiments may permit a casing string to be rotated during running and/or cementing of the casing string. Illustrative embodiments may provide a simplified system that reduces the amount of rods, pins, springs and other similar small parts that must be assembled and maintained at a wellsite or other field environment, providing for a more feasibly implemented solution. Illustrative embodiments provide a single pair of drive rings that may be applied to multiple casing sizes. Drive rings sized to fit around the outer diameter of the mandrel casing hanger may be employed with casings of varying diameter. Illustrative embodiments may be applied to mandrel casing hangers that are attached to running tools with either internal or external threading.
Turning to
Running tool 205 may include a hollow, cylindrical body that connects to mandrel casing hanger 210 with handling threads 230. Mandrel casing hanger 210 may be a mandrel-type casing suspension threaded to running tool 205 with either internal or external handling threads 230, and extend below running tool 205. Handling threads 230 may be an acme profile thread and/or a trapezoidal thread profile for use with higher axial loads. Lower casing string 215 to be run into wellbore 105 may be threaded by casing threading 250 to mandrel casing hanger 210 and extend below mandrel casing hanger 210.
Wellhead 115 may include wellhead housing 220. The inner diameter of wellhead housing 220 may include shoulder 225. Mandrel casing hanger 210 may include a flange that seats onto shoulder 225 to suspend lower casing string 215 above wellbore 105 as lower casing string 215 extends into wellbore 105.
Lower torque ring member (driven ring member) 410 may include a set of trapezoidal teeth 415 and/or protruding portions of torque ring member 410 that extend into flutes 305 of mandrel casing hanger 210. When engaged with mandrel casing hanger 210, torque ring member 410 may be arranged such that troughs 445 between trapezoidal teeth 415 rest and/or seat on the top of flange 300, and trapezoidal teeth 415 extend into flutes 305. One trapezoidal tooth 415 may extend into each flute 305 of mandrel casing hanger 210. In some embodiments, a trapezoidal tooth 415 may extend into every other flute 305 and/or only some flutes 305 may include a trapezoidal tooth 415.
Trapezoidal tooth 415 may include an axially extending side 435 adjacent to driving wall 440. Axially extending side 435 may be parallel to driving wall 440 and/or abut driving wall 440, such that a torque transmission connection is formed when running tool 205 and/or rotary drive rings 400 are rotated in a right-handed direction. Rotation may be initiated by drilling rig 110 via manipulation casing 200. As shown in
Returning to
A casing string torque transfer and suspension system and method for mandrel casing hangers has been described. Further modifications and alternative embodiments of various aspects of the invention may be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the general manner of carrying out the invention. It is to be understood that the forms of the invention shown and described herein are to be taken as the presently preferred embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features of the invention may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of this description of the invention. Changes may be made in the elements described herein without departing from the scope and range of equivalents as described in the following claims. In addition, it is to be understood that features described herein independently may, in certain embodiments, be combined.
This application claims the benefit of U.S. Provisional Application No. 62/397,848 to Burrows filed Sep. 21, 2016 and entitled “APPARATUS, SYSTEM AND METHOD FOR RUNNING OF A CASING STRING,” which is hereby incorporated by reference in its entirety.
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Number | Date | Country | |
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62397848 | Sep 2016 | US |