Patent Publication Number: US-10767443-B2

Title: Burst port sub with dissolvable barrier

Description:
TECHNICAL FIELD 
     The present invention relates to burst port subs (BPS) allowing for at least one of: a tubing, a liner and a casing, in a borehole to be opened at a predetermined pressure and further providing a delayed opening sequence. The present invention relates further to a downhole system comprising a predetermined number of such burst port subs (BPS). 
     BACKGROUND OF THE INVENTION 
     Some different tools and methods that are available today and have a delayed opening sequence are mentioned below:
         Delayed opening valves having oil metering systems allowing pressure to initiate the metering sequence, and actual opening of these valves will be delayed with the time it takes to evacuate a predetermined volume of oil;   Indexing tools requiring a number of pressure cycles for each tool to open up;   Battery powered tools which will open after a predetermined time/pressure.       

     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide burst port subs (BPS) for a tubing or a liner or a casing in a borehole and adapted to be opened at a predetermined pressure and with a delayed opening sequence. 
     Another object of the invention is to provide tools, systems and methods having delayed opening sequence and being improved with respect to the known technique. 
     Yet another object of the invention is to provide tools, systems and methods having delayed opening sequence and representing alternatives to the known technique. 
     According to a first aspect of the invention, this is achieved with a burst port sub having a dissolvable barrier. 
     According to another aspect of the invention, this is achieved with a downhole system comprising a predetermined number of such burst port subs. 
     Burst port subs (BPS)/burst disk subs allow a closed tubing or liner or casing system to be opened at a predetermined pressure. Once this pressure is reached the opening from the inside to the outside of the tubular string is initiated thus providing a fully opened conduit, and the tubular string is no longer pressure containing. 
     This invention will allow for the BPS to be pressurized in order to burst the BPS disk therein and not immediately open up for communication with the outside. This will allow a set time of from e.g. about 0,5-1 hour to e.g. about 2-3 days before the dissolvable barrier in the port of the BPS is dissolved and the open conduit is established. 
     The invention relates to a burst port sub comprising:
         at least one port;   a burst disk arranged on the inner end of the port; and   a dissolvable barrier.       

     The port can be radial. The burst disk can be adapted to burst at a predetermined pressure. The dissolvable barrier can be arranged within the port. The dissolvable barrier can be adapted to dissolve after a predetermined period of time in order to provide an open conduit. The dissolvable barrier can have the shape of one of: a ball, a disc and a plug. The dissolvable barrier can be made of a material being dissolvable by the fluids in the well. The fluids can be pumped in the well after the installation of the BPS. The fluids can have been pumped into the well, before the installation of the BPS. The fluids can already be present in the well. 
     The burst port sub can also comprise a cap. The cap can be arranged on the outer end of the port. 
     Furthermore, the burst port sub can comprise a chamber having an atmospheric pressure. The chamber can contain the dissolvable barrier. The chamber can be arranged in the port and between the burst disk and the cap. 
     The burst port sub can further comprise an insert. The inset can be adapted to be arranged in the port. The dissolvable barrier can be arranged in the insert. The insert can further comprise at least one of: the burst disk, the cap and the atmospheric chamber. The burst disk can have a predetermined thickness. The thickness can set or determine at which predetermined pressure the burst disk will burst or break. The predetermined pressure for bursting the burst disk in the sub port can be in the range from approximately 200 psi to approximately 9000 psi, and particularly from approximately 500 psi to approximately 5000 psi. 
     The predetermined period of time for dissolving the dissolvable barrier can be in the range from approximately 30 minutes to approximately 3 days, and particularly from approximately 1 hour to approximately 2 days. 
     The invention relates also to a downhole system comprising at least one burst port sub according to the invention. Said at least one burst port sub can be peripherally arranged in at least one of: a tubing, a casing and a liner. The downhole system can be adapted for at least one of: an open hole application and a cemented application. 
     The main features of this invention are given in the independent claims. Additional features of the present invention are given in the dependent claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other aspects of the invention are apparent from and will be further elucidated, by way of example(s), with reference to the drawings, wherein: 
         FIG. 1  illustrates a first embodiment of the present invention showing a system comprising a predetermined number of burst port subs. 
         FIG. 2  illustrates a second embodiment of the present invention showing a system comprising a predetermined number of burst port subs. 
         FIG. 3  illustrates a third embodiment of the present invention showing a system comprising a predetermined number of burst port subs. 
         FIG. 4  illustrates a first embodiment of a burst port sub according to the present invention. 
         FIG. 5  illustrates a second embodiment of a burst port sub according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       FIG. 1  illustrates a downhole system, according to the present invention, arranged in an open hole  300  and comprising at least one burst port sub  120 . There can be a predetermined number of burst port subs, BPS,  120 . Each burst port sub  120  is peripherally arranged in a tubing  100  in the well  300 . The tubing  100  can be a production tubing. The term “open hole” is used for wells  300  where there is no liner/casing in the pay zone  310  of the formation  600 . 
       FIG. 2  illustrates another downhole system, according to the present invention, for cemented application and comprising at least one burst port sub  120 . There can be a predetermined number of burst port subs, BPS,  120 . Each burst port sub  120  is peripherally arranged in a tubing  100  in a well  300 . Furthermore, a casing  200  or a liner  200  is cemented in the well  300 . The tubing  100  is arranged within the casing  200  or the liner  200 , and thus an annulus  300  is created therebetween. 
       FIG. 3  illustrates yet another downhole system, according to the present invention, for cemented application and comprising at least one burst port sub  120 . There can be a predetermined number of burst port subs, BPS,  120 . Each burst port sub  120  is peripherally arranged in a liner  200  cemented in a well  300 . 
     As illustrated in  FIG. 1-3 , each burst port sub  120  can be arranged in at least one of: a liner  200 , a casing  200  and a tubing  100 . Each burst port sub  120  can be used in an open hole or cemented application. 
     Each burst port sub  120  can be arranged as an integrated part of at least one of: the liner  200 , the casing  200 , the tubing  100 , and any section thereof. Alternatively, each burst port sub  120  can be arranged peripherally onto the outside surface of at least one of: the liner  200 , the casing  200  and the tubing  100 . Alternatively, each burst port sub  120  can be arranged peripherally onto the inside surface of at least one of: the liner  200 , the casing  200  and the tubing  100 . 
     Said at least one burst port subs  120  can be arranged in the area of a reservoir  600  in a subterranean formation  600 . The subterranean reservoir  600  can contain at least one of: oil and gas. 
     The several burst port subs  120  can be arranged with a predetermined distance from each other. Alternatively, a first distance between two neighbouring burst port subs  120  can vary with respect to a second distance between other two neighbouring burst port subs. 
     The present invention provides a delayed opening sequence of a burst port sub  120 . Each burst port sub  120  can be designed to be opened by different pressure. 
     The burst port sub  120 , according to the invention and shown in  FIGS. 4 and 5 , utilizes a combination of a burst disk  430 ,  530  and a dissolvable barrier  400 ,  500 . 
       FIG. 4  shows one embodiment of a burst port sub  120  according to the invention. 
     The sub  120  can comprise at least one radial port  440  arranged in the sub  120  body  450 . An insert  405  can be arranged in the port  440 . The insert  405  can for example be screwed in the port  440 . The insert  405  can comprise and hold in place a dissolvable barrier  400 . In this embodiment, the dissolvable barrier  400  has the form of a ball  400 . A burst disk  430  can be arranged in the insert  405  and on one end of the insert  405  facing the space  460  within the hollow sub  120 . Alternatively, the burst disk  430  can be arranged directly onto the inner end of the port  440 , that is on the inside  460  surface of the sub  120  body  450 . Furthermore, a cap  410  can be arranged in the insert  405  and on the opposite end of the insert  405 , thus insulating away the outside pressure  310  (in  FIGS. 1 and 2  being the pressure  310  in the annulus  300 ; and in  FIG. 3  being the pressure  310  in the reservoir  600  or formation  600 ). Alternatively, the cap  410  can be arranged directly onto the outer end of the port  440 , that is on the outside surface of the sub  120  body  450 . 
     As said and in this embodiment the sub  120  body  450  can be a part of at least one of: the liner  200 , the casing  200  and the tubing  100 . Furthermore, the space  460  within the hollow sub  120  can be a part of the inside of one of: the liner  200 , the casing  200  and the tubing  100 . 
     The insert  405  can further comprise a chamber  420  with an atmospheric pressure. 
       FIG. 5  shows another embodiment of a burst port sub  120  according to the invention. 
     The sub  120  can comprise at least one radial port  540  arranged in the sub  120  body  550 . An insert  505  can be arranged in the port  540 . The insert  505  can for example be screwed in the port  540 . The insert  505  can comprise and hold in place a dissolvable barrier  500 . In this embodiment, the dissolvable barrier  500  has the shape of a disc  500  or a plug  500 . A burst disk  530  can be arranged in the insert  505  and on a first end of the insert  505  facing the space  560  within the hollow sub  120 . Alternatively, the burst disk  530  can be arranged onto the inner end of port  540 , that is on the inside  560  surface of the sub  120  body  550 . Furthermore, a cap  510  can be arranged in the insert  505  and on the opposite end of the insert  505 , thus insulating away the outside pressure  310  (in  FIGS. 1 and 2  being the pressure  310  in the annulus  300 ; and in  FIG. 3  being the pressure  310  in the reservoir  600  or formation  600 ). Alternatively, the cap  510  can be arranged directly onto the outer end of the port  540 , that is on the outside surface of the sub  120  body  550 . 
     As said and in this embodiment the sub  120  body  550  can be a part of at least one of: the liner  200 , the casing and the tubing  100 . Furthermore, the space  560  within the hollow sub  120  can be a part of the inside of one of: the liner  200 , the casing and the tubing  100 . 
     The insert  505  can further comprise a chamber  520  with an atmospheric pressure. 
     The atmospheric chamber  420 ,  520  will allow the burst disk  430 ,  530  to burst at a predetermined pressure inside at least one of: the tubing  100 , the liner  200  and the casing  200 , and independent of the outside pressure  310 . In other words, independent of the differential pressure across at least one of: the tubing  100 , the liner  200  and the casing  200 . The BPS  120  is in practice independent of the pressure on the outside, because of the atmospheric chamber  420 ,  520  arranged in the port  440 ,  540  or in the insert  405 ,  505  of the BPS  120  body  450 ,  550 . The applied pressure that can be used to burst a chosen burst disk  430 ,  530  in the sub  120  can for example be in the range from about 200 psi to about 9000 psi, and possibly from about 500 psi to about 5000 psi. The applied pressure should not be limited to the above-mentioned pressure ranges. For example applied pressure over 9000 psi can also be appropriate. 
     The insert  405 ,  505  can consist of at least one insert part. This can be so in order to facilitate easy installation of the dissolvable barrier  400 ,  500 , and possibly at least one of: the burst disk  430 ,  530  and the cap  410 ,  510 . 
     The burst disk  430 ,  530  can be a disk/disc with a predetermined thickness that is adapted to burst at a predetermined pressure inside at least one of: the tubing  100 , the liner  200  and the casing  200 . 
     The dissolvable barrier  400 ,  500  can be arranged in a dry and atmospheric chamber  420 ,  520  arranged in the port  440 ,  540  of the sub  120  body  450 ,  550  and thus will not be subject to any exposure of well  300  fluids until the burst disk  430 ,  530  opens up for fluid from the inside  460 ,  560  of the BPS  120  in order to contact the dissolvable barrier  400 ,  500  and start the dissolving process. 
     In  FIGS. 4 and 5 , it is illustrated that the BPS/sub  120  can have an internal thread at each sub end (wherein the inside  460 ,  560  diameter of the sub  120 , in the port  440 ,  540  area, is smaller than the diameter in the rest of the sub  120  body  450 ,  550 , i.e. at both sub  120  ends). These drawings show a box-box thread having screwed a pin end into each side. This allows the sub  120  to be screwed up to at least one of the liner  200 , the casing  200  and the tubing  100 . Alternatively, the BPS/sub  120  can have an external thread at each sub end. 
     The dissolvable barrier  400 ;  500  can be made of a material being dissolvable by fluids in the well  300 . The fluids can be pumped into the well  300 , and/or they can be already existing or present (e.g. previously pumped) in the well  300  (in  FIG. 1-2  this can be done through the tubing  100 , while in  FIG. 3  this can be done through the well  300 ). Such material can for example be aluminum/aluminium. Other metals that can dissolve in both acid(s) or liquid(s)/fluid(s) containing salt(s), can also be suitable as a material for the dissolvable barrier  400 ;  500 . Another example can be magnesium or a combination of several metals. The material of the dissolvable barrier  400 ;  500  can in addition fulfill some requirements for material strength, in addition to the requirement(s) for dissolvability or solubility. 
     Low internal pressure from the sub  120  can push the cap  410 ,  510  away from the port  440 ,  540 . 
     The cap  410 ,  510  can be made of a material fulfilling some requirements for material strength, such as, but not limited to, e.g. a suitable metal or plastic or composite. 
     Additionally or alternatively, the cap can be made of a dissolvable material, similar as for the dissolvable barrier. 
     Once in place, at least one of the tubing  100 , the liner  200  and the casing  200 , can be pressurized to a pressure required for bursting one or several BPS  120  disks  430 ,  530  without allowing for loss of pressure to the annulus  300  (se  FIGS. 1 and 2 ). This will allow for applying full tubing  100  and/or liner  200  and/or casing  200  test pressure and for opening a number of disks  430 ,  530 . 
     After a predetermined period of time, dependent on at least one of: the type of the dissolvable material, pumped fluids, well fluids and well temperature, the dissolvable barrier  400 ,  500  will dissolve and will thus establish communication through all the BPS subs  120 . 
     Additional modifications, alterations and adaptations of the present invention will suggest themselves to those skilled in the art without departing from the scope of the invention as expressed and stated in the following patent claims.