Patent Publication Number: US-2017356256-A1

Title: Trolley for insertion and extraction plants of strings of drill pipes in production wells of hydrocarbons in general and plant equipped with said trolley

Description:
The present invention relates to a trolley for insertion and extraction plants of strings of drill pipes in production wells of hydrocarbons in general. 
     The field of the invention relates to the production of gaseous or liquid hydrocarbons in general, extracted from the respective wells using strings of pipes (“tubing”) suitably assembled, connecting the single pipes with a head/tail coupling until the length necessary for reaching the production area or reservoir has been covered. 
     This type of processing envisages the cyclic insertion and extraction of strings of pipes from the production well by means of a work-over rig, in order to allow both ordinary maintenance interventions and also for restoring the production activity. These insertion operations of drill strings are effected by connecting or joining single pipes having a standard length of about 9 m, with a threaded head-to-tail coupling. In the extraction phase of the strings, the same pipes, however, are disconnected or separated from each other in correspondence with the same threaded couplings. 
     Consequently, the extraction and insertion movements of the strings must be interrupted, at every interval of 9 meters of pipe, for the time necessary for unscrewing and screwing the threaded connection couplings between adjacent pipes. These interruptions, however, are undesired as they negatively affect the production recovery, causing additional operational costs and loss of production. In the known art described above, the time necessary for transferring the single 9 meter drill pipes from the pipe rack to the work-over rig also contributes to increasing the interruption times of the production activity of the well. 
     In order to overcome these drawbacks, plants are known in which at least two single pipes are reciprocally joined, with a head-tail coupling, outside the rig. In this way, longer pipe stands are obtained with respect to standard stands, which allows the dead times of the extraction unit to be reduced ((Aaron Sinnott: “Taking tubulars offline—Reprinted from Oilfield Technology”—30 Sep. 2013, XP055207318). 
     In moving pipe stands composed of two or more pipes having a standard length, the problem arises, however, of availing of a suitable transportation trolley, which is suitable for moving and supporting pipes having a greater length and weight with respect to standard values. 
     The main objective of the present invention is therefore to provide a trolley for insertion and extraction plants of strings of drill pipes in production wells of hydrocarbons in general, wherein the above-mentioned trolley is suitable for transferring the mentioned pipe stands from and towards the pipe rack and work-over rig. 
     This and other objectives are achieved by means of the trolley and plant of claims  1  and  7  respectively. Preferred embodiments of the invention can be found in the remaining claims. 
     With respect to known trolleys used in plants for the insertion and extraction of pipes in production wells of hydrocarbons in general, that according to the present invention offers the advantage of allowing the safe movement of pipe stands having greater lengths and weights with respect to those used in this type of application. 
     The trolley of the invention also offers the advantage of operating exclusively by gravity in the transportation of pipe stands, whose weight serves for maintaining their correct position during the transfer. 
     This solves the problem of safely and simply moving pipe stands from and towards the plant, without the help of complex hydraulic systems for holding them in the correct transfer position. 
    
    
     
       These and other objectives, advantages and characteristics appear evident from the following description of a preferred embodiment of the trolley and plant of the invention, illustrated, for non-limiting purposes, in the figures of the enclosed drawings. 
       In the same: 
         FIGS. 1 to 4  illustrate the plant of the invention; 
         FIG. 5  illustrates the layout of the logistic connection, separation and control pole of the pipes; 
         FIG. 6  illustrates a perspective view of the trolley for moving pipe stands used in the plant of  FIGS. 1 to 4 ; 
         FIG. 7  illustrates a perspective view of a detail of the slide of the trolley of  FIG. 6 ; 
         FIG. 8  illustrates a detail of the pulling fork assembled on the slide of  FIG. 7 ; 
         FIG. 9  illustrates the slide of  FIG. 7  without the fork of  FIG. 8 ; 
         FIG. 10  illustrates the detail of the male of a pipe stand moved with the trolley of the previous figures; 
         FIG. 11  illustrates the trolley of  FIG. 6  in a front view; 
         FIG. 12  illustrates the trolley of  FIG. 6 , in a longitudinal section, in the boost phase of the pipe stands of  FIG. 10 ; 
         FIG. 13  illustrates a perspective and sectional view of the trolley of  FIG. 12 ; 
         FIG. 14  illustrates the trolley of  FIGS. 12 and 13  in the initial boost phase of the pipe stands; 
         FIGS. 15 and 16  illustrate the trolley of  FIG. 6 , in a longitudinal and perspective section, during the pulling phase of the pipe stands of  FIG. 10 ; 
         FIGS. 17 to 19  illustrate a perspective view of the trolley of  FIG. 6 , in different transporting positions of the pipe stands on the guide of the pipe rack; and 
         FIG. 20  illustrates an exploded view of the trolley of the invention. 
     
    
    
     As illustrated in  FIG. 1 , a work-over rig comprises a tower  1  equipped with a travelling block  2 , to which the pipe stands  8  consisting of a plurality of single joints  3  are connected, in turn removed from a pipe rack  4  and hoisted towards the rig floor  6  by sliding on a V-door  5 . 
     In the example illustrated, the mentioned stand  8  is obtained by the coupling of two pipes  3   a  and  3   b  in correspondence with the connection  22  of  FIG. 1 , but it is understood that the invention is not limited to the number of pipes forming the mentioned stand  8 . 
     After assembling the pipes  3   a  and  3   b  on the pipe rack  4 , the stand  8  thus obtained is hoisted, by means of the travelling block  2 , onto the rig floor  6 , so that it can be coupled with the stand  9  already in the well ( FIG. 4 ). 
     According to the invention, in order to facilitate the transfer of the stands  8  from and towards the rig floor  6 , at least one trolley  10  is advantageously used, that can be moved by means of a chain  11  ( FIG. 2 ), or with equivalent systems (hydraulic or mechanical systems), not shown. 
     The management of the plant of the previous figures can be effected according to the scheme of  FIG. 5 . In the same, a certain number of work-over rigs,  16 ,  17 ,  18  is served by an assembly and disassembly station  19  of the stands  8  outside the same rigs. The transportation of these stands from the station  19  to the same rigs  16 - 18  is effected with the help of special means  20 . 
     The trolley  10  of the invention, as represented in  FIGS. 6 to 9 and 20 , comprises an external carter  12 , substantially U-shaped, overturned over a guide  13  for transporting the pipe stands . 8  onto the pipe rack  4 . 
     The trolley  10  is equipped with the slide  21  of  FIG. 7 , in turn composed of the sliding base  22  of  FIG. 9 , on which the pipe stand  8  rests. The above-mentioned base  22  is, in turn, completed by the fork  23  of  FIG. 8 , whose arc-shaped bottom  24  is removably housed in the corresponding seat  25  of the base  22  of  FIG. 9 . Thanks to this embodiment, the dimensions of the forks  23  can be selected in relation to the diameter of the pipe stand  8  in  FIG. 10 . 
     The slide  21  also comprises a plate  26 , destined for receiving the thrust of the tool joint  31  of the pipe stand  8  during their transportation towards the tower  1 . The same slide  21  of the trolley  10  is, in turn, slidingly supported above a corresponding guiding channel  35  ( FIGS. 13, 19 ). 
     As better illustrated in  FIGS. 12 and 16 , the plate  26  of the slide  21  is equipped with a transversal pin  27  slidingly guided in the direction of the arrows F 1  and F 2  inside slots  28  positioned on the side walls of the same carter  12  ( FIGS. 17 and 18 ). The movement of the slide  21  in the direction of the arrow F 1  of  FIG. 16  is effected in contrast with the action of a spring  29  interposed between said plate  26  and a fixed shoulder  30  of the same carter  12 . 
     In the boost phase towards the tower  1  of the pipe stand  8 , in the direction of the arrow F 2  of  FIGS. 12 to 14 , the plate  26  pushes against the tool joint  31  of the above-mentioned pipe stand  8 , crushing the spring  29  until it interferes against the shoulder  30 . In this way, the pipe stand  8  is caused to slide above the guide  13 , in the direction of the tower  1 . The movement of the slide  21  on the guide  13  is advantageously effected with the help of rolls  32 , in turn sliding on respective rails  33  of the same guide  13  ( FIG. 19 ). 
     In the contrary movement of the slide  21 , arrow F 1  of  FIGS. 15 and 16 , the fork  23  grips the shoulder  34  of the tool joint  31  of  FIGS. 10, 15 and 16 . In these conditions, the position of the plate  26  of the slide  21  corresponds to the rest position of the spring  29 . With this movement of the slide  21 , the pip stand  8  is removed from the tower  1  in the direction of the outlet of the pipe rack  4 .