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.

What is claimed is: 
     
         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, and   at 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, and   wherein 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; and   whereby 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; and   wherein 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; and   whereby 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 D 1  across the central axis, and an engaged configuration defining a second diameter D 2  across the central axis,   wherein the slips in the open configuration do not engage a pipe string having a diameter less than D 1  within the passage, and the slips in the engaged configuration engage the pipe string having the diameter of D 2  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; and   wherein 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; and   wherein 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 D 1  of 6.75 inches, and the engaged configuration of the slips defines a diameter D 2  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; and   the 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; and   wherein 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; and   whereby all mechanical loads transferred between the slips and the actuator pass through the carrier ring.