Method and apparatus for creating an annular seal in a wellbore

Abstract

A workstring apparatus for creating an annular seal in a wellbore is described. Workstring comprises at least one packer apparatus comprising a body portion and an elastomeric packer element which is deformable into an outwardly deployed condition to deform wellbore casing. A fluid accumulator is provided to hold fluid to actuate at least one hydraulic cylinder of the packer apparatus. An electrically powered pump is operable to pump fluid from accumulator into the hydraulic cylinders of packer apparatus to deform the elastomeric packer element outwardly. A wireline connects the workstring to the surface and provides electrical power to the workstring. Wireline may be an electrical feed such as a composite rod or e-coil.

1 . A method of creating an annular seal in the annulus between a wellbore and a casing disposed in the wellbore, wherein at least one tubular casing element is disposed in a wellbore, said tubular casing element comprising an external sealing element disposed thereon, the method comprising:
 locating a workstring in the wellbore, the workstring comprising:
 at least one packer apparatus comprising a body portion, an elastomeric packer element disposed on said body portion and at least one hydraulic cylinder, wherein said elastomeric packer element is configured to be deformed into an outwardly deployed condition in response to actuation of said at least one hydraulic cylinder to deform casing located in the wellbore; 
 a fluid accumulator arranged to hold fluid for actuation said at least one hydraulic cylinder; 
 an electrically powered pump arranged to pump fluid from said fluid accumulator to actuate said at least one hydraulic cylinder; and 
 a wireline arranged to supply electrical power to said electrically powered pump and hold said workstring at a desired position in a wellbore; 
   moving the workstring to a position at which said elastomeric packer element is located at the same depth as said external sealing element;   operating said electrically powered pump to actuate said at least one hydraulic cylinder to deform said elastomeric packer element outwardly to contact and deform said tubular casing element outwardly and compress said external sealing element against the surface of a wellbore or casing in which said tubular casing element is located to form an annular seal.   
     
     
         2 . A method according to  claim 1 , wherein a plurality of tubular casing elements having external sealing elements disposed thereon are disposed in a wellbore, and wherein said workstring comprises a plurality of packer apparatuses each having an elastomeric packer element, the method further comprising:
 moving the workstring to a position in the wellbore at which said elastomeric packer elements are located at the same depths as said external sealing elements; and   operating said electrically powered pump to actuate said plurality of packer apparatuses to deform the respective plurality of elastomeric packer elements outwardly to contact and deform a plurality of tubular casing elements outwardly and compress said plurality of external sealing elements against the surface of a wellbore or casing in which said tubular casing element is located to form a plurality of annular seals.   
     
     
         3 . A method according to  claim 1 , wherein the workstring further comprises sensor apparatus configured to sense characteristics of the formation of the portion of wellbore in which the workstring is located and/or to locate the position of external sealing elements of tubular casing elements disposed in the wellbore, the method further comprising:
 moving the workstring through the wellbore to a position at which the sensor apparatus indicates to an operator of the workstring that an annular seal is desirable at that location in the wellbore and/or an external sealing element is located adjacent said at least one elastomeric packer element; and   operating said electrically powered pump to deform said elastomeric packer element outwardly to contact and deform said tubular casing element outwardly and compress said external sealing element against the surface of a wellbore or casing in which said tubular casing element is located to form an annular seal.   
     
     
         4 . A method according to  claim 3 , wherein the step of moving the workstring through the wellbore to a position at which the sensor apparatus indicates to an operator of the workstring that an annular seal is desirable at that location in the wellbore and/or an external sealing element is located adjacent said at least one elastomeric packer element includes operating fibre optic cables to sense wellbore parameters to indicate characteristics of the casing and/or fluid migration in the wellbore to the operator. 
     
     
         5 . A method according to  claim 1 , wherein said at least one packer apparatus comprises locking device configured to retain said elastomeric packer element in the outwardly deployed condition, said at least one packer apparatus further comprising a detachable portion containing said elastomeric packer element, the method further comprising:
 after said at least one packer apparatus has been operated to form an annular seal in the wellbore, detaching said detachable portion of said at least one packer apparatus of which the locking device has retained the elastomeric packer element in the outwardly deployed condition to deform casing to leave said detachable portion in the wellbore to act as a bridge plug.   
     
     
         6 . A method according to  claim 5 , further comprising pumping cement into the wellbore to sit on top of said detachable portion. 
     
     
         7 . A method according to  claim 1 , further comprising:
 lining a wellbore with a plurality of tubular casing elements;   pumping cement into the annulus between said plurality of tubular casing elements and the surface of the wellbore or casing in which said plurality of casing elements is located; and   locating said work string in the wellbore and operating said work string to form at least one annular seal in said wellbore before said cement has set.   
     
     
         8 . A workstring apparatus for creating an annular seal in the annulus between a wellbore and a casing disposed in the wellbore, the workstring comprising:
 at least one packer apparatus comprising:
 a first body portion removably connectable to a second body portion; 
 an elastomeric packer element disposed on said first body portion, said elastomeric packer element configured to be deformed into an outwardly deployed condition in response to actuation of at least one piston disposed on said second body portion; 
 a locking device disposed on said first body portion to retain said elastomeric packer element in the outwardly deployed condition; 
 wherein said first body portion can be disconnected from said second body portion after said elastomeric packer element is moved to the outwardly deployed condition to deform casing in a wellbore in which the assembly is disposed to enable retrieval of said second body portion from said wellbore; 
   a fluid accumulator arranged to hold fluid for actuation said at least one hydraulic cylinder;   an electrically powered pump arranged to pump fluid from said fluid accumulator to actuate said at least one hydraulic cylinder; and   a wireline arranged to supply electrical power to said electrically powered pump and hold said workstring at a desired position in a wellbore;   wherein operating said electrically powered pump to actuate said at least one hydraulic cylinder deforms said elastomeric packer element outwardly to contact and deform a tubular casing element in which said packer apparatus is located outwardly to form an annular seal.   
     
     
         9 . An apparatus according to  claim 8 , further comprising sensor apparatus configured to sense characteristics of the formation of the portion of wellbore in which the workstring is located and/or to locate the position of an external sealing element of tubular casing elements disposed in the wellbore. 
     
     
         10 . An apparatus according to  claim 9 , wherein said sensor apparatus comprises at least one fibre optic cable and control apparatus configured to sense characteristics of the formation of the portion of wellbore in which the workstring is located and/or to locate the position of an external sealing element of tubular casing elements disposed in the wellbore based on light signals from said at least one fibre optic cable. 
     
     
         11 . An apparatus according to  claim 8 , wherein said locking means comprises:
 a first plurality of teeth disposed on an outer surface of said first body portion; and   a ratchet member having a second plurality of teeth disposed thereon for engagement with said first plurality of teeth;   wherein said ratchet member is able to move in a first direction along said first body portion during deformation of said elastomeric packer element but is prevent from movement in a second direction, opposite to said first direction by engagement of said first and second pluralities of teeth.   
     
     
         12 . An apparatus according to  claim 11 , wherein said ratchet member comprises a split ring. 
     
     
         13 . An apparatus according to  claim 11 , wherein said locking device further comprises a ratchet retainer ring in engagement with said elastomeric packer element. 
     
     
         14 . An apparatus according to  claim 8 , further comprising an electrically operated release apparatus to enable disconnection of the first body portion from the second body portion. 
     
     
         15 . An apparatus according to  claim 8 , further comprising a floating piston in fluid communication with both:
 fluid held in the fluid accumulator; and   fluid located in a wellbore in use;   such that fluid held in the fluid accumulator is isolated from fluid located in the wellbore but is at an equal pressure to fluid located in the wellbore.   
     
     
         16 . An apparatus according to  claim 8 , further comprising a plurality of packer apparatuses. 
     
     
         17 . A method of placing a casing patch in a wellbore, the method comprising:
 mounting a tubular casing element having an external sealing element disposed thereon on a workstring according to  claim 8 ;   moving said work string to a location in the wellbore at which a casing patch is required;   operating said work string to deform said tubular casing element to form an annular seal at the desired location of said casing patch and disconnect said tubular casing element from the work string; and   moving the work string away from said tubular casing element forming said casing patch.   
     
     
         18 . A method of completing a wellbore, the method comprising:
 lining a wellbore with at least one tubular casing element, said at least one tubular casing element comprising an external sealing element disposed thereon; and   creating an annular seal between a wellbore and a casing disposed in the wellbore according to the method of  claim 1 .   
     
     
         19 . A tubular casing element for a wellbore, the tubular casing element comprising an external sealing element disposed thereon, wherein the external sealing element is a tubular sleeve formed from two or more of the following materials:
 an elastomer;   a composite material;   an alloy;   a metal; or   polyterafluoroethylene.