Method for completing a borehole

Abstract

The invention relates to a method for completing a borehole ( 1, 2 ) prior to the start of production, wherein after making the borehole ( 1, 2 ) the borehole wall ( 3 ) is anchored in a sealed manner with a conveying tube ( 4 ) and/or casing tube, and the borehole wall ( 3 ) is perforated with perforation units ( 5 ) at desired points. To complete a borehole without the use of cemented conveying tubes and/or casing tubes, it is proposed that the conveying tube ( 3 ) and/or casing tube be provided on its outer surface with a swellable sealing jacket ( 6 ), wherein the sealing jacket ( 6 ) swells after activation and anchors the annular gap between the conveying tube ( 4 ) and/or casing tube and the borehole wall ( 3 ) in a sealed manner and simultaneously centres the conveying tube ( 4 ) and/or casing tube in the borehole ( 1, 2 ).

1 . A method for completing a borehole before the start of production, wherein after the introduction of the borehole the borehole wall is anchored sealingly by means of a conveying tube and/or casing tube, and the borehole wall is perforated at desired locations by means of perforation units, characterized in that the conveying tube and/or casing tube are/is provided on their/its outer face with a swellable sealing jacket, wherein after activation the sealing jacket swells and anchors the annular gap sealingly between the conveying tube and/or casing tube and the borehole wall and at the same time centers the conveying tube and/or casing tube in the borehole. 
   
   
       2 . A method as claimed in  claim 1 , characterized in that the activation and swelling of the sealing jacket are carried out after perforation. 
   
   
       3 . A method as claimed in  claim 1 , characterized in that the perforation pressure and/or the borehole temperature and/or the liquid which is generated in the production zone are/is used for activating the sealing jacket for swelling purposes. 
   
   
       4 . A method as claimed in  claim 1 , characterized in that the material used for the sealing jacket is a viscous material and/or a rubber or thermoplastic. 
   
   
       5 . A method as claimed in  claim 1 , characterized in that the sealing jacket is designed to be deactivatable and, after deactivation, is permeable to liquids or gases. 
   
   
       6 . A method as claimed in  claim 5 , characterized in that chemical and/or thermal activation stimulators are used for deactivation. 
   
   
       7 . A method as claimed in  claim 6 , characterized in that the chemical activation stimulators used are aggressive media, for example acids, which dissolve the sealing jacket or parts of the sealing jacket. 
   
   
       8 . A method as claimed in  claim 6 , characterized in that, for thermal deactivation, the activation stimulator used is a heating module which, for activation, is brought to the desired location in the conveying tube and/or casing tube. 
   
   
       9 . A method as claimed in  claim 1 , characterized in that different sealing jackets are used for different horizons, so that, if different activation stimulators are used, a selective opening of the sealing jackets is achieved, and these orifices can be connected to the conveying tube for production. 
   
   
       10 . A method as claimed in  claim 1 , characterized in that at least one perforation unit is inserted inside the conveying tube and/or casing tube. 
   
   
       11 . A method as claimed in  claim 10 , characterized in that the conveying tube and/or casing tube are/is designed in a module-like manner together with the perforation unit, each module consisting of a section of the conveying tube and/or casing tube and of a perforation unit. 
   
   
       12 . A method as claimed in  claim 11 , characterized in that all the necessary components, such as charges, ignition cable sections and wire pieces, are preinstalled in the module, the terminals for electrical and ballistic contact being installed fixedly at one end of each module, and, at the other end, the terminals being prestressed by means of a spring, so that, after the connection of two modules, reliable electrical and ballistic contact between the individual modules is ensured. 
   
   
       13 . A method as claimed in  claim 12 , characterized in that the terminals of the first module which are to be coupled are coupled to the terminals of the contiguous second module so that the terminals lie opposite one another in their axial direction and thus, during use, transfer electrical and ballistic contact, the terminals of at least one module being acted upon with force in the direction of the terminals of the contiguous other module, so that the end faces of the adjacent terminals always touch one another during use. 
   
   
       14 . A method as claimed in  claim 1 , characterized in that, to trigger the perforation unit or perforation units, a gas-pressure-activated ignition mechanism is used which is installed at the lower end of the perforation unit. 
   
   
       15 . A method as claimed in  claim 14 , characterized in that preferably, in single-horizon completions, the gas-pressure-activated ignition mechanism activates an impact fuse. 
   
   
       16 . A method as claimed in  claim 1 , characterized in that, particularly in multiple-horizon completions, a separate electrical detonator is used for each perforation zone. 
   
   
       17 . A method as claimed in  claim 16 , characterized in that the detonators are connected via wires, the ignition mechanism containing an induction appliance, which is operated by the gas pressure, and the induced current then igniting the detonators. 
   
   
       18 . A method as claimed in  claim 1 , characterized in that the ignition mechanism used is a wire-operated firing head which is installed on the top side of the conveying tubing before installation takes place in the lower region of the borehole, and, for ignition, a module on the cable is moved into the borehole and latches on the ignition mechanism on top, and, by electrical connection of the borehole head to the perforation unit, the electrical signals required for igniting the detonators are locked on, and, after detonation, the ignition mechanism is separated from the conveying tubing and is moved out of the borehole with the aid of the cable. 
   
   
       19 . A method as claimed in  claim 1 , characterized in that the elements of the perforation unit dissolve automatically after detonation. 
   
   
       20 . A method as claimed in  claim 19 , characterized in that reactive materials, such as zinc, aluminum or magnesium, are used for the charge housings of the hollow charges. 
   
   
       21 . A method as claimed in  claim 20 , characterized in that non-reactive sleeve materials which generate a fine sand-like dust, such as glass or porcelain, are used for the charge housings. 
   
   
       22 . A conveying tube and/or casing tube for carrying out the method as claimed in  claim 1 , characterized in that the conveying tube and/or casing tube has on its outer face a swellable sealing jacket. 
   
   
       23 . A conveying tube and/or casing tube as claimed in  claim 22 , characterized in that the material of the sealing jacket is a viscous material and/or a rubber or thermoplastic. 
   
   
       24 . A conveying tube and/or casing tube as claimed in  claim 22 , characterized in that the sealing jacket is deactivatable and, after deactivation, is permeable to liquids. 
   
   
       25 . A conveying tube and/or casing tube as claimed in  claim 22 , characterized in that the conveying tube and/or casing tube is designed in a module-like manner, and at least one perforation unit is inserted in each module. 
   
   
       26 . A conveying tube and/or casing tube as claimed in  claim 25 , characterized in that the terminals for electrical and ballistic contact are installed fixedly at one end of each module and, at the other end, the terminals are prestressed by means of a spring, so that, after the connection of two modules, reliable electrical and ballistic contact between the individual modules is ensured. 
   
   
       27 . A conveying tube and/or casing tube as claimed in  claim 26 , characterized in that the terminals of the first module which are to be coupled are coupled to the terminals of the contiguous second module so that the terminals lie opposite one another in their axial direction and thus, during use, transfer electrical and ballistic contact, the terminals of at least one module being acted upon with force in the direction of the terminals of the contiguous other module, so that the end faces of the adjacent terminals always touch one another during use. 
   
   
       28 . A conveying tube and/or casing tube as claimed in  claim 22 , characterized in that the perforation units contain charge housings of the hollow charges which dissolve automatically after detonation. 
   
   
       29 . A conveying tube and/or casing tube as claimed in  claim 28 , characterized in that the charge housings of the hollow charges consist of reactive materials, such as zinc, aluminum or magnesium, or consist of non-reactive materials which, after the detonation of the hollow charges, generate a fine sand-like dust, such as glass or porcelain.