Well tubing rotator and hanger system

Abstract

In one aspect a rotating hanger comprises a dognut sleeve having a bore and an outer profile compatible for support in the casing bowl and sealing thereto and a tubular hanger mandrel fitted rotatably to the dognut sleeve's bore and having an upper shoulder projecting above the dognut sleeve for interaction with casing bowl holddown screws which, when engaged, restrain rotation and prevent ejection from the casing bowl. In another aspect, an improved well tubing rotator and hanger system is provided the rotatable tubing hanger, a tubular connector sub threaded to the hanger mandrel and a rotator splined to the connector sub, the splined connector sub enabling rotational coupling without imposing hanger loads into the rotator which enables use of smaller, low profile and economical rotators. In another aspect, a rotator having a threaded nozzle wellhead connection is convertible to a flanged rotator.

1 . A rotating tubing hanger for suspending a string of tubing from a casing bowl fitted with holddown screws comprising: 
 a dognut sleeve having a bore and an outer profile compatible for support by the casing bowl and sealing thereto; and    a tubular hanger mandrel fitted rotatably to the dognut sleeve's bore and having a lower end from which the tubing string is suspended and an upper end projecting upwardly above the dognut sleeve for forming an upper shoulder and positioned so that the holddown screws can be actuated to engage the upper shoulder and prevent the hanger mandrel from rotation and ejection from the casing bowl or can be actuated to disengage from the upper shoulder.    
     
     
         2 . The tubing hanger of  claim 1  wherein the bore of the dognut sleeve further comprises upward facing shoulder and the hanger mandrel further comprises a outer and downward facing shoulder for rotatable support on the dognut sleeve's upward facing shoulder.  
     
     
         3 . The tubing hanger of  claim 2  wherein the hanger mandrel's upper shoulder is positioned so that: 
 the hanger mandrel is locked against rotation and prevented from ejection when engaged by the holddown screws;  
 the hanger mandrel is free for rotation when the holddown screws are disengaged from the upper shoulder; and  
 both hanger mandrel and dognut sleeve are free for removal from the casing bowl when the holddown screws are fully disengaged.  
 
     
     
         4 . The tubing hanger of  claim 3  wherein the hanger mandrel's upper shoulder is beveled so that when the holddown screws are engaged, the upper shoulder is locked against rotation and restrained from ejection from the casing bowl.  
     
     
         5 . The tubing hanger of  claim 4  wherein the bore of the upper end of the hanger mandrel is threaded.  
     
     
         6 . A rotator for a coupling with a rotating tubing hanger supported in a casing bowl of a wellhead having a wellhead flange, comprising: 
 a flange housing for mounting to the wellhead flange, said housing having a bore therethrough and a concentric counterbore extending upwardly from a lower mounting face and terminating at a top shoulder;    a concentric ring gear supported in the counterbore and sandwiched between the top shoulder and a lower retaining ring, the ring gear having an inner diameter being fitted with internal spline;    a drive gear fitted to the flange housing for rotatably driving the ring gear;    a concentric and cylindrical collar having an outer surface which is partially fitted with splines compatible with and for rotational coupling with the ring gear, and having an inner surface which is partially fitted with splines for coupling with the rotating tubing hanger.    
     
     
         7 . The rotator of  claim 6  further comprising upper and lower annular bushing rings positioned between the top shoulder and ring gear and ring gear and retaining ring respectively.  
     
     
         8 . The rotator of  claim 7  further comprising seals between 
 the collar's outer surface and the counterbore below the ring gear  
 the collar's outer surface and the bore above the ring gear  
 the collar inner surface and the rotating tubing hanger above the tubing hanger coupling.  
 
     
     
         9 . The rotator of  claim 6  wherein the flange housing has an upper face and the bore extends into a threaded nozzle.  
     
     
         10 . The rotator of  claim 6  wherein the ring gear, drive gear and collar are positioned between the lower and upper faces so that the threaded nozzle can be machined off of the flange housing for converting the upper face to a flanged mounting face.  
     
     
         11 . An improved well tubing rotator and hanger system is provided for a wellhead having a casing bowl, a wellhead flange, and holddown screws actuable to extend into the casing bowl, said system comprising: 
 a rotatable two-piece tubing hanger having a dognut sleeve supported in the casing bowl and having a bore, a tubular hanger mandrel rotatable in the dognut sleeve's bore and having an upper shoulder which, upon actuation of the holddown screws, can be engaged by the holddown screws to lock rotation and disengaged from the holddown screws to permit rotation of the hanger mandrel and to permit removal of the rotating tubing hanger from the casing bowl;    a rotator mounted to the wellhead flange; and    a tubular connector sub, threaded at a lower end to the rotating hanger and splined at an upper end for rotational-only coupling with the rotator.    
     
     
         12 . The improved system of  claim 8  wherein the rotator comprises: 
 a flange housing for mounting to the wellhead flange, said housing having a bore therethrough and a concentric counterbore extending upwardly from a lower mounting face and terminating at a top shoulder;  
 an ring gear retained concentrically within the counterbore, the ring gear being rotatable by a drive gear; and  
 a collar positioned concentric within the counter-bore and being rotatable with the ring gear, and having an interface with the connector sub so as transmit rotation from the ring gear to the connector sub without incurring axial loads.  
 
     
     
         13 . The improved system of  claim 9  wherein 
 the ring gear is sandwiched between the top shoulder and a lower retaining ring has an inner diameter being fitted with internal spline;  
 the drive gear is fitted to the flange housing for rotatably driving the ring gear;  
 the collar has an outer surface which is at least partially fitted with splines compatible with and for rotational coupling with the ring gear, and having an inner surface which is at least partially fitted with splines for coupling with the connector sub.  
 
     
     
         14 . The improved system of  claim 10  further comprising upper and lower annular bushing rings positioned between the top shoulder and ring gear and ring gear and retaining ring respectively.  
     
     
         15 . The improved system of  claim 8  further comprising seals between 
 the collar's outer surface and the counterbore below the ring gear  
 the collar's outer surface and the bore above the ring gear  
 the collar inner surface and the rotating tubing hanger above the tubing hanger coupling.  
 
     
     
         16 . The improved system of  claim 8  wherein the hanger mandrel's upper shoulder is positioned so that: 
 the hanger mandrel is engaged by the holddown screws when actuated into the casing bowl so as to lock rotation of the hanger mandrel;  
 the hanger mandrel is free for rotation when the holddown screws are actuated so as to be partially extracted from the casing bowl and are disengaged from the upper shoulder; and  
 both hanger mandrel and dognut sleeve are free for removal from the casing bowl when the holddown screws are fully disengaged.  
 
     
     
         17 . A method for safely servicing a well's wellhead while avoiding a blowout, the wellhead being fitted with a tubing rotator and a casing bowl fitted with holddown screws, the method comprising: 
 providing a two-piece rotating hanger comprising a dognut sleeve having a bore and an outer profile which is compatible for support in the casing bowl and sealing thereto, and a tubular hanger mandrel fifted rotatably to the dognut sleeve's bore, the mandrel having a lower end from which a tubing string is suspended and an upper end projecting upwardly above the dognut sleeve for forming an upper shoulder and connected drivably to the tubing rotator;    actuating the holddown screws to a first position to engage the hanger mandrel's upper shoulder for safely restraining rotation and preventing ejection of the rotating hanger from the casing bowl; and    removing the tubing rotator.    
     
     
         18 . The wellhead servicing method of  claim 14  further comprising relieving stored rotational energy in the tubing string by actuating the holddown screws to disengage from the upper shoulder and permitting the hanger mandrel to rotate.  
     
     
         19 . The wellhead servicing method of  claim 15  wherein once pressure has been reduced below the tubing hanger the method further comprises disengaging the holddown screws from the upper shoulder sufficiently so that the hanger mandrel and dognut sleeve can be removed fully from casing bowl.