DRILL FLOOR ROTARY SLIP UNIT WITH HYDRAULIC SWIVEL

Abstract

hydraulic slip unit for a rotary drive of a rig floor comprises a main body including hydraulically operated slips disposed within a passage that can engage a pipe string within the passage to transmit vertical loads and torque for rotation of the pipe string. A hydraulic swivel is connected to the main body, wherein the swivel includes a first portion attached to the main body to rotate therewith and a second portion slidably mounted to the first portion to rotate relative thereto. Both first and second portions include oil passages therethrough in fluid communication with one another during relative rotation. During rotation of the main body, the second portion is connectable to static hydraulic supply lines that do not rotate, and fluid from the supply lines can travel through the respective oil passages to provide hydraulic power to the slips in the main body to selectively move them.

Description

TECHNICAL FIELD

The following disclosure relates to mechanical equipment used in oil field operations, and in particular to gripping apparatus for supporting tubulars such as drill pipe, collars and casing. In one embodiment, a hydraulically powered slip unit is adapted for mounting in a rotary drive of a rig's drill floor to transmit vertical loads and rotational torque to a pipe string to rotate the pipe string in the borehole when it is disconnected from a top drive, and to allow hydraulic actuation of the slip unit during rotation of the pipe string in the borehole.

BACKGROUND

In the makeup and breakout of pipe strings during drilling and other downhole operations, it is known to use slips to support the weight of the pipe string in the wellbore when the pipe string is disconnected from the top drive. Slips are typically received in a structure know as a bowl that surrounds the pipe and is supported by the rotary table or drilling floor. The bowl interior has inclined, downwardly converging surfaces such that as the slips (which are positioned around the pipe) move downward into the bowl, the slips move radially inward to increasingly engage the pipe, resulting in a so-called self-tightening behavior. The slips and bowl are designed to support the weight of the pipe string (i.e., load) and resist release until the load is supported by other means (e.g., reattachment to the top drive). As the load is released, the slips can be moved upwards to release the pipe.

It is known to equip slip bowls with hydraulic actuators to selectively move the slips up and down in the bowl. Conventional hydraulically-powered slip units are typically connected to a hydraulic power source using hydraulic supply lines that are manually pulled across the drill floor and attached to the slip unit using quick-disconnect hydraulic fittings. To avoid tangling the hydraulic supply lines, rotation of the pipe string must stop when the supply lines are connected to allow actuation of the slip unit. The supply lines are then disconnected from the slip unit when rotation of the pipe string is to resume. This repeated connection and disconnection of the supply lines results in increased labor and wear on the equipment. A need therefore exists for a hydraulically-powered slip unit that does not require disconnection of the hydraulic supply lines to allow for rotation of the pipe string.

It is know that when conducting drilling or other downhole operations in certain formations and/or under certain conditions, the pipe string can become stuck to the side of the borehole if near-continuous rotation of the pipe string is not maintained. Under such conditions, pausing rotation of the pipe string during the time hydraulic slips are in use greatly increases the risk of sticking. A need therefore exists for a hydraulically-powered slip unit that can be used during rotation of the pipe string, i.e., where disconnection of the hydraulic supply lines is not required to allow rotation.

SUMMARY

In one aspect thereof, a hydraulic slip unit is provided for a rotary drive of a rig floor. The slip unit comprises a main body including a bowl portion defining a vertical passage therethrough along a central axis and having a plurality of inclined surfaces converging downwardly toward the central axis. A plurality of slips is slidably mounted on the inclined surfaces for moving along the inclined surfaces. At least one hydraulic actuator is operatively mechanically connected to the plurality of slips and is hydraulically operable to selectively move the slips along the inclined surfaces between a relatively upper, radially outward “open” position for releasing a pipe in the passage, and a relatively lower, radially inward “engaged” position for engaging the pipe in the passage. A hydraulic swivel is connected to the main body, wherein the swivel includes a spindle attached to the bowl portion to rotate with the bowl portion and a sleeve that encircles the spindle and is slidably mounted to rotate relative to the spindle. Each of the spindle and the sleeve includes respective oil passages formed therein and connection points for the oil passages. The oil passages of the spindle are in fluid communication with the oil passages of the sleeve such that the connection points of the spindle are in fluid communication with the connection points of the sleeve during relative rotation of the sleeve with respect to the spindle. The connection points of the spindle are in fluid communication with the hydraulic actuators and the connection points of the sleeve are connectable to non-rotating hydraulic supply lines. During rotation of the main body and the attached spindle, the sleeve can be attached to static hydraulic supply lines that do not rotate, and fluid from the static hydraulic supply lines can operate the hydraulic actuators to selectively move the slips between the “open” position and the “engaged” position during such rotation.

In another aspect thereof, a hydraulic slip unit for a rotary drive of a rig floor comprises a main body including a plurality slips disposed within a passage around a central axis and at least one hydraulic actuator that, when supplied with hydraulic power, can selectively move the slips between an open configuration and an engaged configuration. When in the open configuration, the slips do not engage a pipe string within the passage, and when in the engaged configuration, the slips engage the pipe string within the passage to transmit vertical loads and torque for rotation of the pipe string. A hydraulic swivel is connected to the main body, wherein the swivel includes a first portion attached to the main body to rotate with the main body. The first portion includes oil passages fluidly connected at a first end to the hydraulic actuator in the main body. A second portion of the hydraulic swivel is slidably mounted to the first portion to rotate relative to the first portion. The second portion includes oil passages fluidly connectable at a first end to static hydraulic supply lines. Second ends of the respective oil passages of the first portion and the second portion are in fluid communication with one another during relative rotation. During rotation of the main body and first portion, the second portion is connectable to static hydraulic supply lines that do not rotate, and fluid from the static hydraulic supply lines can travel through the respective oil passages to the actuator to provide hydraulic power to the actuator to selectively move the slips between the open configuration and the engaged configuration.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding, reference is now made to the following description taken in conjunction with the accompanying Drawings in which:

FIG. 1 is a perspective view of a drill floor rotary slip unit with hydraulic swivel in accordance with one embodiment;

FIG. 2 is a side view of the rotary slip unit of FIG. 1;

FIG. 3 is a top view of the rotary slip unit of FIG. 2 with the slips in the “upper” or “open” position;

FIG. 4 is a side cross-sectional view of the rotary slip unit of FIG. 2 with the slips in the “open” position taken along Line A-A of FIG. 2;

FIG. 5 is a top view of the rotary slip unit of FIG. 2 with the slips in the “lower” or “engaged” position;

FIG. 6 is a side cross-sectional view of the rotary slip unit of FIG. 2 with the slips in the “engaged” position taken along Line A-A of FIG. 2; and

FIG. 7 is a perspective view of the rotary slip unit of FIG. 1 mounted in the rotary drive of a rig's drill floor.

DETAILED DESCRIPTION

Referring first to FIGS. 1 and 2, there is illustrated a drill floor rotary slip unit 100 in accordance with one embodiment. For purposes of illustration, the main body of the slip unit 100 is depicted semi-transparent in FIGS. 1 and 2 to better show its interior features. The slip unit 100 includes a main body 102 operably connected to a hydraulic swivel 104. The main body 102 is externally configured to define a cap portion 106 and a bowl portion 108. The cap portion 106 is configured to extend outward from the bowl portion 108 to define underside support surfaces 110 and lateral drive surfaces 112. The underside support surfaces 110 bear on the upper portions of the rotary (e.g., the rotary bushing (see FIG. 7)) to transmit vertical loads from the main body 102 to the rotary. Similarly, the lateral drive surfaces 112 can interfit with lateral portions of the rotary to transmit torque from the rotary drive to the main body 102. In the illustrated embodiment, the lateral drive surfaces 112 are configured in a square shape with beveled corners to interfit with a known API-specified rotary adapter; however, in other embodiments, the lateral drive surfaces can be configured in other shapes to interface with different rotary drives or rotary bushings. The main body 102 of the slip unit 100 is internally configured to define a vertical passage 114 extending along a central axis 116 for receiving the pipe string (not shown). The interior surface of the bowl portion 108 includes a plurality of inclined, downwardly converging surfaces 118 disposed around the central axis 116.

The rotary slip unit 100 further includes a plurality of slips 120 and one or more hydraulic actuators 122. Each slip 120 is disposed in the vertical passage 114 adjacent to a respective one of the inclined surfaces 118 and operatively mechanically connected to one end of at least one of the hydraulic actuators 122. The other end of each hydraulic actuator 122 is operatively mechanically connected to the bowl portion 108. Each hydraulic actuator 122 can selectively extend and retract upon receiving hydraulic power. As further described below, the hydraulic actuators 122 are operatively fluidly connected to the swivel portion 104 to receive hydraulic power from the swivel portion. The slips 120 can include jaws or dies 124 to enhance the grip on the pipe. In the illustrated embodiment, the dies 124 are removable from the slips 120 to allow replacement when worn out; however, in other embodiments the jaws can be integral to the slips.

Referring now also to FIGS. 3-6, the hydraulic actuators 122 can be selectively actuated by the application of hydraulic power via fluid connections to move the slips 120 up and down along the inclined surfaces 118 within the bowl portion 108. When the actuators 122 are extended, the slip unit 100 is in an “open” configuration (FIGS. 3 and 4), i.e., the slips 120 are positioned relatively higher along the inclines 118 and radially away from the axis 116 to define therebetween a relatively larger first diameter D1, where D1 is larger than the diameter of the pipe to be supported, so the slips do not grip the pipe. When the actuators 122 are retracted, the slip unit 100 is in an “engaged” configuration (FIGS. 5 and 6), i.e., the slips 120 are positioned relatively lower along the inclines 118 and radially inward towards the axis 116 to define therebetween a relatively smaller second diameter D2, where D2 is the diameter of the pipe to be supported, so the slips grip the pipe. A comparison of the top views shown in FIGS. 3 and 5, respectively, illustrates that the slips 120 in the “open” configuration (FIG. 3) are moved radially away from the center axis 116 so the dies 124 do not contact the pipe (they are hidden from view behind the carrier 126), whereas the slips in the “engaged” configuration (FIG. 5) are moved radially towards the center axis so that the dies can engage a pipe in the passage 114. In embodiments of the rotary slip unit 100 having an even number of slips 120, the respective diameters D1 and D2 are the respective distances, measured through the central axis 116, between the gripping surfaces of opposing slips. In embodiments of the rotary slip unit 100 having an odd number of slips 120 (or where the slips do not directly oppose one another across the central axis), the respective diameters D1 and D2 are understood to be two times the slip “radius,” which is the nominal distance from the central axis 116 to the gripping surface of the slips.

In some embodiments, the hydraulic actuators 122 can be directly connected to the slips 120 for moving them along the inclined surfaces 118, whereas in other embodiments, the actuators can be indirectly connected to the slips. For example, in the illustrated embodiment, the actuators 122 are operatively connected to the slips 120 by use of an intermediate ring-shaped carrier 126. In particular, the moving ends of the actuators 122 are connected to the carrier 126, which in turn is slidably connected to the tops of the slips 120. Moving the carrier 126 up and down causes the slips 120 to move up and down along the inclined surfaces 118, and the slidable connection between the top of the slips and the carrier allows the slips to move radially as needed to follow the inclined surface. This arrangement has the advantage of allowing one end of the hydraulic actuators 122 to be fixedly attached the bowl portion 108 of the unit. However, other arrangements for operative mechanical connection of the actuators 122 to the slips 120 can be used within the scope of the current invention.

As best seen in FIG. 4, the hydraulic swivel 104 comprises an inner spindle 128 and an outer sleeve 132. The inner spindle 128 is disposed below the main body 102 along the axis 116 and affixed to the bowl portion 108 so that it moves (e.g., rotates) with the bowl portion. The spindle 128 defines a central passage 130 that is concentric with the axis 116 and allows the pipe string to pass through. The outer sleeve 132 encircles the spindle 128 but is slidably mounted to allow the sleeve and spindle to rotate relative to one another around the axis 116. The sleeve 132 can be secured to a static structure (e.g., a static part of the drilling rig) to prevent rotation of the sleeve when the spindle 128 and the main body 102 are rotated by the rotary. The outer sleeve 132 has oil passages 134 formed therein which are fluidly connected with external connection points 136 for attachment of hydraulic supply lines 138. Similarly, the spindle has oil passages 140 formed therein which are fluidly connected by way of respective connection points to the actuators 122. The various oil passages 134 of the sleeve 132 are in fluid connection with respective oil passages 140 of the spindle 128 to form continuous fluid paths from the respective static connection ports 136 to the respective hydraulic actuators 122 rotating with the main body 102 such that hydraulic power from the hydraulic supply lines 138 can selectively operate the actuators of the slip unit 100, i.e., even while the spindle is rotating relative to the sleeve. Accordingly, as long as the sleeve 132 is secured to a static structure, the hydraulic supply lines 138 can remain attached and provide hydraulic power to the actuators 122 of the slip unit 100 while the main body 102 rotates and grips the pipe string. It will be appreciated that while the illustrated embodiment includes the sleeve 132 held static while the spindle 128 is attached to the main body 102 to rotate with the bowl 108, in other embodiment the sleeve can be attached to the main body to rotate with the bowl and the spindle can be held static (with the static hydraulic supply lines 138 now being connected to the static spindle). The swivel 104 transfers hydraulic fluid between the relatively moving sleeve 132 and spindle 128 in both cases.

Referring now to FIG. 7, there is illustrated the drill floor rotary slip unit 100 installed in a rotary drive 150 of a rig floor 152. In the illustrated embodiment, the rotary drive 150 includes an API standard rotary bushing 154 which receives, supports and rotates the main body 102 of the slip unit. The outer sleeve 132 of the hydraulic swivel 104 is mechanically attached to a static portion 156 of the rig floor to prevent rotation of the sleeve when the main body 102 rotates with the rotary drive. Hydraulic supply lines 138 are connected to the static sleeve 132. As previously described, the oil passages 134 of the sleeve 132 are in continuous fluid communication with the oil passages 140 of the spindle 128, which are in turn fluidly connected to the actuators 122 of the bowl 108. As a result, hydraulic fluid from the supply lines 138 can operate the actuators 122 to selectively move the slips 120 between the “open” and “engaged” configurations whether the main body 102 is rotating or static. Use of the slip unit 100 in a rotary drive 150 during breakout and makeup operations supports the pipe string vertical load while simultaneously transmitting torque from the rotary drive to rotate the pipe string in the borehole to prevent sticking of the pipe string when the pipe string is disconnected from the top drive. The permanent hydraulic connection for the slip actuators 122 provided by the hydraulic swivel 104 allows the hydraulic slip unit 100 to be activated, e.g., for breakout and makeup operations, during rotation of the pipe string.

In some embodiments, the drill floor rotary slip unit 100 can have a vertical load capacity within the range from 450,000 pounds to 550,000 pounds for supporting the pipe string in the borehole. In some embodiments, the drill floor rotary slip unit 100 can have a rotational torque capacity within the range from 23,400 foot-pounds to 28,600 foot-pounds for rotating the pipe string in the borehole. In some embodiments, the drill floor rotary slip unit 100 can have a vertical load capacity of 500,000 pounds for supporting the pipe string in the borehole and a rotational torque capacity of 26,000 foot-pounds for rotating the pipe string in the borehole. In some embodiments the slip unit 100 can have a vertical passage with a maximum unobstructed diameter of 6.75 inches, i.e., when the slips are in the fully open configuration (e.g., FIGS. 3 and 4) and minimum a slip-to-slip diameter of 4.50 inches, i.e., when the slips are in the engaged configuration (e.g., FIGS. 5 and 6). For many embodiments, the slip unit 100 does not need to provide sufficient torque for drilling further into the formation; it is only necessary that the slip unit provide sufficient torque for rotating the pipe in the borehole to prevent the pipe string from sticking within the borehole. In some embodiments, the slip unit 100 can have a cap portion 106 with a substantially square profile (viewed from above) with a width within the range from 20.125 inches to 22.125 inches from one lateral drive surface 112 to the opposite lateral drive surface (i.e., measured perpendicular to the drive surfaces). In some embodiments, the slip unit 100 can have a cap portion 106 with a substantially square profile with a width of 21.125 inches from one lateral drive surface 112 to the opposite lateral drive surface (measured perpendicular). In some embodiments, the slip unit 100 can have an overall height (viewed from the side) of 28.50 inches from the top of the main body 102 to the bottom of the hydraulic swivel 104. In some embodiments, the main body 102 of the slip unit 100 can have a cap portion 106 with a height of 5.25 inches and a bowl portion 108 with a height of 15.00 inches. In some embodiments, the hydraulic swivel 104 can have a height of 7.75 inches, i.e., extending 7.75 inches beneath the main body 102.

Although the preferred embodiment has been described in detail, it should be understood that various changes, substitutions and alterations can be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A hydraulic slip unit for a rotary drive of a rig floor, the slip unit comprising: a main body including:a bowl portion defining a vertical passage therethrough along a central axis and having a plurality of inclined surfaces converging downwardly toward the central axis,a plurality of slips slidably mounted on the inclined surfaces for moving along the inclined surfaces, andat least one hydraulic actuator operatively mechanically connected to the plurality of slips and hydraulically operable to selectively move the slips along the inclined surfaces between a relatively upper, radially outward “open” position for releasing a pipe in the passage, and a relatively lower, radially inward “engaged” position for engaging the pipe in the passage;a hydraulic swivel connected to the main body, wherein the swivel includes:a spindle attached to the bowl portion to rotate with the bowl portion,a sleeve that encircles the spindle and is slidably mounted thereto to rotate relative to the spindle,wherein each of the spindle and the sleeve includes respective oil passages formed therein and connection points for the oil passages, and wherein the oil passages of the spindle are in fluid communication with the oil passages of the sleeve such that the connection points of the spindle are in fluid communication with the connection points of the sleeve during relative rotation of the sleeve with respect to the spindle, andwherein the connection points of the spindle are in fluid communication with the hydraulic actuators and the connection points of the sleeve are connectable to hydraulic supply lines affixed to a rig floor; andwhereby during rotation of the main body and the attached spindle relative to the rig floor, the sleeve does not rotate relative to the rig floor, and the connection points of the sleeve can be attached to the hydraulic supply lines affixed to the rig floor, and fluid from the hydraulic supply lines affixed to the rig floor can operate the hydraulic actuators to selectively move the slips between the “open” position and the “engaged” position during such rotation.

2. A hydraulic slip unit in accordance with claim 1, wherein the at least one hydraulic actuator has a respective first end directly mechanically connected to the bowl portion and a respective second end directly mechanically connected to each one of the plurality of slips, and wherein extending the at least one hydraulic actuator moves the plurality of slips relative to the bowl portion.

3. A hydraulic slip unit in accordance with claim 1, further comprising: a carrier ring having a first portion and a second portion;wherein the first portion of the carrier ring is mechanically connected to the plurality of slips to receive mechanical loads from the slips and transmit mechanical loads to the slips; andwherein the second portion of the carrier ring is mechanically connected to a first respective end of the at least one hydraulic actuator to receive mechanical loads from the actuator and transmit mechanical loads to the actuator; andwhereby all mechanical loads transferred between the slips and the actuator pass through the carrier ring.

4. A hydraulic slip unit in accordance with claim 3, wherein the carrier ring is disposed above the plurality of slips such that raising the carrier ring relative to the bowl portion raises the plurality of slips relative to the bowl portion and lowering the carrier ring relative to the bowl portion lowers the plurality of slips relative to the bowl portion.

5. A hydraulic slip unit in accordance with claim 4, wherein the carrier ring is disposed above the at least one hydraulic actuator such that extending the hydraulic actuator raises the carrier ring relative to the bowl portion and retracting the hydraulic actuator lowers the carrier ring relative to the bowl portion.

6. A hydraulic slip unit in accordance with claim 5, wherein a second respective end of the at least one hydraulic actuator is fixedly attached to the bowl portion.

7. A hydraulic slip unit in accordance with claim 3, wherein the carrier ring has an annular configuration defining a central opening disposed along the central axis and comprising a portion of the vertical passage of the slip unit.

8. A hydraulic slip unit in accordance with claim 7, wherein the central opening of the carrier ring has a ring diameter equal to a first diameter defined by the spacing, measured across the central axis, between slips with the slips in the relatively upper, radially outward “open” position.

9. A hydraulic slip unit for a rotary drive of a rig floor, the slip unit comprising: a main body including a bowl portion and a plurality slips disposed within a passage around a central axis and at least one hydraulic actuator supplied with hydraulic power for selectively moving the slips between an open configuration defining a first diameter D1 across the central axis, and an engaged configuration defining a second diameter D2 across the central axis,wherein the slips in the open configuration do not engage a pipe string having a diameter less than D1 within the passage, and the slips in the engaged configuration engage the pipe string having the diameter of D2 within the passage to transmit vertical loads and torque for rotation of the pipe string between the slips and the bowl portion;a hydraulic swivel connected to the main body, wherein the swivel includes:a first portion attached to the main body to rotate with the main body, the first portion including oil passages fluidly connected at a first end to the hydraulic actuator in the main body;a second portion slidably mounted to the first portion to rotate relative to the first portion, the second portion including oil passages fluidly connectable at a first end to static hydraulic supply lines;wherein second ends of the respective oil passages of the first portion and the second portion are in fluid communication with one another during relative rotation; andwherein during rotation of the main body and first portion relative to a rig floor, the second portion does not rotate relative to the rig floor and is connectable to static hydraulic supply lines affixed to the rig floor; andwherein fluid from the static hydraulic supply lines can travel through the respective oil passages to the actuator to provide hydraulic power to the actuator to selectively move the slips between the open configuration and the engaged configuration.

10. A hydraulic slip unit in accordance with claim 9, wherein the open configuration of the slips defines a diameter D1 of 6.75 inches, and the engaged configuration of the slips defines a diameter D2 of 4.50 inches.

11. A hydraulic slip unit in accordance with claim 9, further comprising: a cap portion extending laterally outwardly from an upper part of the bowl portion to define underside support surfaces and a plurality of lateral drive surfaces;the underside support surfaces being configured to bear on the upper portions of a rotary bushing a rotary drive of a rig floor to transfer vertical loads received by the cap portion from the bowl portion of the main body to the rotary busing; andthe plurality of lateral drive surfaces being configured to interfit with lateral portions of the rotary bushing to transmit torque received by the cap portion from the rotary bushing to the bowl portion of the main body.

12. A hydraulic slip unit in accordance with claim 11, wherein the lateral drive surfaces of the cap portion are configured in a substantially square shape with beveled corners to interfit with an API-specified rotary adapter on the rotary bushing of the rig floor.

13. A hydraulic slip unit in accordance with claim 11, wherein the cap portion, viewed from above, has a substantially square shape with a width, measured perpendicularly from one lateral drive surface to the opposite lateral drive surface, within the range from 20.125 inches to 22.125 inches.

14. A hydraulic slip unit in accordance with claim 13, wherein the cap portion, viewed from above, has a substantially square shape with a width, measured perpendicularly from one lateral drive surface to the opposite lateral drive surface, of 21.125 inches.

15. A hydraulic slip unit in accordance with claim 9, wherein the slip unit has a vertical load capacity within the range from 450,000 pounds to 550,000 pounds for supporting the pipe in the borehole and a rotational torque capacity within the range from 23,400 foot-pounds to 28,600 foot-pounds for rotating the pipe in the borehole.

16. A hydraulic slip unit in accordance with claim 15, wherein slip unit has a vertical load capacity of 500,000 pounds for supporting the pipe in the borehole and a rotational torque capacity of 26,000 foot-pounds for rotating the pipe in the borehole.

17. A hydraulic slip unit in accordance with claim 9, further comprising: a carrier ring having a first portion and a second portion;wherein the first portion of the carrier ring is mechanically connected to the plurality of slips to receive mechanical loads from the slips and transmit mechanical loads to the slips; andwherein the second portion of the carrier ring is mechanically connected to a first respective end of the at least one hydraulic actuator to receive mechanical loads from the actuator and transmit mechanical loads to the actuator; andwhereby all mechanical loads transferred between the slips and the actuator pass through the carrier ring.