Pipe guides and methods of guiding pipes in snubbing units

Abstract

An hydraulic snubbing unit has a pair of hydraulic cylinders for moving travelling snubbing slips towards and away from stationary snubbing slips to snub a pipe through the snubbing unit, the hydraulic cylinders having spaced, parallel cylinder rods. A pipe guidance apparatus has pipe guides between the stationary snubbing slips and the travelling snubbing slips, the pipe guides each having a pair of cylinder rod openings spaced apart from one another and slidably receiving the rods of the hydraulic cylinders and a pipe guidance opening located between the cylinder rod openings and slidably guiding the pipe, and a pipe guide spacer having extendable and contractible interconnections between the pipe guides. In a contracted condition of the pipe guide spacer, the interconnections are contracted and the pipe guides are moved into proximity to one another by the simultaneous movement of the cylinder rods slips towards the stationary slips, and in an expanded condition, the interconnections are extended and the pipe guides are moved apart from one another by the simultaneous movement of the cylinder rods away from the stationary slips to provide lateral support of the pipe at intervals along the pipe.

1 . A pipe guidance apparatus for guiding a pipe during snubbing of the pipe, comprising:—
 a. a plurality of pipe guides;   b. the pipe guides each having a pair of jack rod openings spaced apart from one and a pipe guidance opening located between the jack rod openings for slidably guiding the pipe;   c. the jack rod openings being mutually aligned and the pipe guidance openings being mutually aligned; and   d. a pipe guide spacer;   e. the pipe guide spacer comprising extendable and contractible interconnections between the pipe guides; and   f. the pipe spacer having a contracted condition, in which the interconnections are contracted and the pipe guides are moved towards one another, and an expanded condition, in which the interconnections are extended and the pipe guides are moved apart from one another.   
   
   
       2 . A pipe guidance apparatus as claimed in  claim 1 , wherein the extendable and contractible interconnections comprise two parallel sets of tubular members, the tubular members of each of the sets being telescopically extendable and retractable relative to one another and each of the sets of tubular members being provided, at one end of the set, with a pull member for telescopically extending the tubular members. 
   
   
       3 . A pipe guidance apparatus as claimed in  claim 2 , wherein an outermost one of the tubular members of each set of tubular members, at an opposite end of the set, has an abutment for retaining the remainder of the set on contraction of the set. 
   
   
       4 . A pipe guidance apparatus as claimed in  claim 2 , wherein each of the pull members has, at one end thereof, an anchor member located within an innermost one of the tubular members of the respective set of tubular members, said innermost tubular member having an end abutment engageable by the anchor member to telescopically extend said respective set of tubular members on extension of the pull member from the innermost tubular member. 
   
   
       5 . A pipe guidance apparatus as claimed in  claim 4 , wherein each of the tubular members has, on one end thereof, a further anchor member and at an opposite end thereof a further end abutment, the further end abutment of each of the tubular members being engageable by the further anchor member of another of the tubular members to effect the telescopic extension of the tubular members. 
   
   
       6 . A pipe guidance apparatus as claimed in  claim 5 , wherein the further end abutments are formed by end caps on the tubular members. 
   
   
       7 . A pipe guidance apparatus as claimed in  claim 5 , wherein the further anchor members comprise annular collars on the tubular members. 
   
   
       8 . In an hydraulic snubbing unit having stationary snubbing slips, travelling snubbing slips and a pair of spaced, parallel hydraulic jacks for moving the travelling snubbing slips towards and away from the stationary snubbing slips to snub a pipe through the snubbing unit, the hydraulic jacks comprising hydraulic cylinders and jack rods extending from the cylinders, the improvement comprising:
 a pipe guidance apparatus for guiding a section of the pipe between the stationary snubbing slips and the travelling snubbing slips;   the pipe guidance apparatus comprising:—a plurality of pipe guides between the stationary snubbing slips and the travelling snubbing slips;   the pipe guide guides each having a pair of cylinder rod openings spaced apart from one another and slidably receiving the jack rods of the hydraulic cylinders and a pipe guidance opening located between the cylinder rod openings and slidably guiding the pipe; and   a pipe guide spacer;   the pipe guide spacer comprising extendable and contractible interconnections between the pipe guides; and   the pipe spacer having a contracted condition, in which the interconnections are contracted and the pipe guides are moved into proximity to one another by movement of the travelling slips towards the stationary slips, and an expanded condition, in which the interconnections are extended and the pipe guides are moved apart from one another by movement of the travelling slips away from the stationary slips.   
   
   
       9 . An hydraulic snubber unit as claimed in  claim 8 , wherein the extendable and contractible interconnections comprise two parallel sets of tubular members, the tubular members of each of the sets being telescopically extendable and retractable relative to one another, and each including a connecting member for telescopically extending and contracting the tubular members, the connecting members each having one end connected for movement with the travelling slips and an opposite end extending into the tubular members. 
   
   
       10 . An hydraulic snubber unit as claimed in  claim 8 , wherein each of the connecting members has at one end thereof an anchor member located within an innermost one of the tubular members of the respective set of tubular members, said innermost tubular member having an end abutment engageable by the anchor member to telescopically extend said innermost tubular member. 
   
   
       11 . An hydraulic snubber unit as claimed in  claim 10 , wherein each of the tubular members of each set, other than an outermost one of the tubular members, has on one end thereof a further anchor member and each of the tubular members has at an opposite end thereof a further end abutment, the further end abutment being engageable by one of the further anchor members to effect the telescopic extension of the tubular members. 
   
   
       12 . An hydraulic snubber unit as claimed in  claim 8 , wherein the extendable and contractible interconnections comprise two parallel sets of telescopically extendable and retractable tubular member connecting the pipe guides in a ladder-like assembly. 
   
   
       13 . A method of guiding a pipe as the pipe is being snubbed through snubbing unit having stationary snubbing slips, traveling snubbing slips and hydraulic jacks for moving the traveling slips towards and away from the stationary slips, the hydraulic jacks comprising hydraulic cylinders and jack rods extending from the hydraulic cylinders, the jack rods being connected to the traveling snubbing slips, the method comprising the steps of:—gripping the pipe by the travelling snubbing slips during movement of the pipe through the snubbing unit;
 extending and retracting the hydraulic jacks to displace the travelling snubbing slips relative to the stationary snubbing slips and thereby to displace the pipe through the snubbing unit; and   guiding a section of the pipe extending between the stationary snubbing slips and the travelling snubbing slips by laterally restraining the pipe section at intervals spaced apart along the section of the pipe.   
   
   
       14 . A method as claimed in  claim 13 , in which the step of guiding a section of the pipe comprises guiding the pipe by pipe guides spaced apart along the section of the pipe, and which further includes moving the pipe guides towards one another on movement of the travelling slips towards the stationary slips and moving the pipe guides apart from one another on movement of the travelling slips away from the stationary slips. 
   
   
       15 . A method as claimed in  claim 14 , which includes guiding the pipe guides along the pipe by sliding engagement of the pipe guides with the jack rods of the hydraulic cylinders.