Abstract:
An apparatus for facilitating the connection of tubulars, said apparatus comprising a winch ( 15 ), at least one wire line ( 4, 5 ), and a device ( 2 ) for gripping the tubular ( 3 ), the arrangement being such that, in use, the winch ( 15 ) can be used to winch said at least one wire ( 4, 5 ) and said device ( 2 ) to position a tubular ( 3 ) below said top drive.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    This invention relates to a method and apparatus for facilitating the connection of tubulars using a top drive and is, more particularly but not exclusively, for facilitating the connection of a section or stand of casing to a string or casing.  
           [0003]    2. Description of the Related Art  
           [0004]    In the construction of wells such as oil or gas wells, it is usually necessary to line predrilied holes with a string of tubulars known as casing. Because of the size of the casing required, sections or stands of say two sections of casing are connected to each other as they are lowered into the well from a platform. The first section or stand of casing is lowered into the well and is usually restrained from falling into the well by a spider located in the platform&#39;s floor. Subsequent sections or stands of casing are moved from a rack to the well centre above the spider. The threaded pin of the section or stand of casing to be connected is located over the threaded box of the casing in the well to form a string of casing. The connection is made-up by rotation therebetween.  
           [0005]    It is common practice to use a power tong to torque the connection up to a predetermined torque in order to perfect the connection. The power tong is located on the platform, either on rails, or hung from a derrick on a chain. However, it has recently been proposed to use a top drive for making such connection.  
           [0006]    Prior to the present invention, pipe handling devices moved pipes to be connected to a tubular string from a rack to the well centre using articulated arms or, more commonly, a pipe elevator suspended from the drilling tower.  
           [0007]    The present invention provides an alternative to these devices.  
         SUMMARY OF THE INVENTION  
         [0008]    Accordingly, a first aspect of the present invention provides an apparatus for facilitating the connection of tubulars, said apparatus comprising a winch, at least one wire line and a device for gripping a tubular the arrangement being such that, in use, the winch can be used to winch said at least one wire and said device to position a tubular below said top drive.  
           [0009]    Further features are set out in claims 2 to 6.  
           [0010]    According to a second aspect of the present invention there is provided a method of facilitating the connection of tubulars using a top drive and comprising the steps of attaching at least one wire to a tubular, the wire depending from the top drive or from a component attached thereto, and winching the wire and the tubular upwards to a position beneath the top drive.  
           [0011]    According to a third aspect of the present invention there is provided an apparatus for facilitating the connection of tubulars using a top drive, said apparatus comprising an elevator and a pair of bails, characterised in that said elevator is, in use, movable in relation to said pair of bails.  
           [0012]    According to a fourth aspect of the present invention there is provided: an apparatus for facilitating the connection of tubulars using a top drive, said apparatus comprising an elevator ( 102 ) and a pair of bails ( 103 ,  104 ), characterised in that said elevator ( 102 ) is, in use, movable relative to said pair of bails ( 103 ,  104 ). 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    For a better understanding of the present invention and in order to show how the same may be carried into effect reference will now be made, by way of example, to the accompanying drawings in which:  
         [0014]    [0014]FIGS. 1 a  to  1   e  are perspective views of an apparatus in accordance with a first embodiment of the present invention at various stages of operation; and  
         [0015]    [0015]FIGS. 2 a  to  2   d  are perspective views of an apparatus in accordance with a second embodiment of the invention at various stages of operation. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0016]    Referring to FIGS. 1 a  to  1   e  there is shown an apparatus which is generally identified by reference numeral  1 .  
         [0017]    The apparatus  1  comprises a clamp  2  for retaining a tubular  3 . The clamp  2  is suspended on wires  4 ,  5  which are connected thereto on opposing sides thereof. The wire  5  passes through an eye  6  in lug  7  which is attached to a spherical bearing in arm  8  of a suspension unit  9  at the point at which the arm  8  is connected to a hydraulic motor. The wire is connected to the hydraulic motor  10  in a corresponding manner. The suspension unit  9  is of a type which enables displacement of the tubular  3  when connected to a tool  17  (see below), relative to a top drive  13 , along a number of different axes. The wires  4 ,  5  pass across the suspension unit  9  and over pulley wheels  11  which are rotatably arranged on a plate  12 . The plate  12  is fixed in relation to a top drive generally identified by reference numeral  13 . The wires  4 ,  5  then pass over drums  14  to which the wires  4 ,  5  are also connected. The drums  14  are rotatable via a hydraulic winch motor  15 .  
         [0018]    In use, the clamp  2  is placed around a tubular below a box  16  thereof. The hydraulic winch motor  15  is then activated, which lifts the tubular  3  (conveniently from a rack) and towards a tool  17  for gripping the tubular  3  (FIG. 1 b ). The tubular  3  encompasses the tool  17  at which point the hydraulic winch motor  15  is deactivated (FIG. 1 c ). During this operation the elevator  18  is held away from the tool  17  by piston and cylinders  19 ,  20  acting on bails  21  and  22 . The suspension unit  9  allows the hydraulic motor  10  and the arrangement depending therebelow to move in vertical and horizontal planes relative to the top drive  13 . The eyes  6  in lugs  7  maintain the wires  4  and  5  in line with the tubular  3  during any such movement. The tool  17  may now be used to connect the tubular to the tubular string. More particularly, the tool may be of a type which is inserted into the upper end of the tubular, with gripping elements of the tool being radially displaceable for engagement with the inner wall of the tubular so as to secure the tubular to the tool. Once the tool is secured to the tubular, the hydraulic motor  10  is activated which rotates the tool  17  and hence the tubular  3  for engagement with a tubular string held in a spider.  
         [0019]    The clamp  2  is now released from the tubular  3 , and the top drive  13  and hence apparatus  1  is now lifted clear of the tubular  3 . The elevator  18  is now swung in line with the apparatus  1  by actuation of the piston and cylinders  19  and  20  (FIG. 1 d ).  
         [0020]    The top drive  13  is then lowered, lowering the elevator  18  over the box  16  of the tubular  3 . The slips in the elevator  18  are then set to take the weight of the entire tubular string. The top drive is then raised slightly to enable the slips in the spider to be released and the top drive is then lowered to introduce the tubular string into the borehole.  
         [0021]    Referring to FIGS. 2 a  to  2   d  there is shown an apparatus which is generally identified by reference numeral  101 .  
         [0022]    The apparatus  101  comprises an elevator  102  arranged at one end of bails  103 ,  104 . The bails  103 ,  104  are movably attached to a top drive  105  via axles  106  which are located in eyes  107  in the other end of the bails  103 ,  104 . Piston and cylinders  108 ,  109  are arranged between the top drive  105  and the bails. One end of the piston and cylinders  108 ,  109  are movably arranged on axles  110  on the top drive. The other end of the piston and cylinders  108 ,  109  are movably arranged on axles  111 ,  112  which are located in lugs  113 ,  114  located approximately one-third along the length of the bails  103 ,  109 .  
         [0023]    The elevator  102  is provided with pins  115  on either side thereof and projecting therefrom. The pins  115  are located in slots  116  and  116   g.  A piston  117 ,  118  and cylinder  119 ,  120  are arranged in each of the bails  103 ,  104 . The cylinders are arranged in slot  121 ,  122 . The piston  117 ,  118  are connected at their ends to the pins  115 . The cylinders  119 ,  120  are prevented from moving along the bails  103 ,  104  by cross members  123  and  124 . A hole is provided in each of the cross members to allow the pistons to move therethrough.  
         [0024]    In use, a tubular  125  is angled from a rack near to the well centre. The tubular may however remain upright in the rack. The clamp  102  is placed around the tubular below a box  126  (FIG. 2 a ). The top drive is raised on a track on a derrick. The tubular is lifted from the rack and the tubular swings to hang vertically (FIG. 2 b ). The piston and cylinders  108 ,  109  are actuated, extending the pistons allowing the bails  103 ,  104  to move to a vertical position. The tubular  125  is now directly beneath a tool  127  for internally gripping and rotating the tubular  125  (FIG. 2 c ). The pistons  117 ,  118  and cylinders  119 ,  120  are now actuated. The pins  115  follow slot  116  and the clamp  102  moves upwardly, lifting the tubular  125  over the tool  127  (FIG. 2 d ). The tool  127  can now be actuated to grip the tubular  125 .  
         [0025]    At this stage the elevator  102  is released and the top drive  105  lowered to enable the tubular  125  to be connected to the string of tubulars in the slips and torqued appropriately by the top drive  105 .  
         [0026]    The pistons  117 ,  118  and cylinders  119 ,  120  are meantime extended so that after the tubular  125  has been connected the top drive  105  can be raised until the elevator  102  is immediately below the box. The elevator  102  is then actuated to grip the tubular  125  firmly. The top drive  105  is then raised to lift the tubular string sufficiently to enable the wedges in the slips to be withdrawn. The top drive  105  is then lower to the drilling platform, the slips applied, the elevator  102  raised for the tubular  125  and the process repeated.  
         [0027]    While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.