Subsea well intervention module

Abstract

Subsea well intervention module for well intervention operations to be performed in a well from a surface vessel via a wireline. The intervention module comprises a supporting structure, an attachment means for removably attaching the supporting structure to a structure of a well head or an additional structure, a well manipulation assembly, a navigation means having at least one propulsion unit for manoeuvring the module in the water, and a control system for controlling the intervention operations. The invention also relates to an intervention system and an intervention method.

1 . Subsea well intervention module ( 100 ) for well intervention operations to be performed in a well ( 101 ) from a surface vessel ( 102 ) via a wireline, comprising:
 a supporting structure ( 110 ),   an attachment means ( 111 ) for removably attaching the supporting structure to a structure of a well head ( 120 ) or an additional structure,   a navigation means ( 105 ), and   a well manipulation assembly ( 125 ),   
       wherein the navigation means comprises a buoyancy system ( 117 ) adapted for regulating a buoyancy of the submerged well intervention module. 
     
     
         2 . Subsea well intervention module according to  claim 1 , wherein the subsea well intervention module has a top part and a bottom part, the bottom part having a higher weight than the top part. 
     
     
         3 . Subsea well intervention module according to  claim 1 , wherein the supporting structure is a frame structure having an outer form and defining an internal space containing the well manipulation assembly and the navigation means, the well manipulation assembly and the navigation means both extending within the outer form. 
     
     
         4 . Subsea well intervention module according to  claim 1 , wherein the navigation means has at least one propulsion unit ( 115 ,  116 ) for manoeuvring the module in the water ( 104 ). 
     
     
         5 . Subsea well intervention module according to  claim 1 , wherein the supporting structure is a frame structure having a height, a length and a width corresponding to the dimensions of a standard shipping container. 
     
     
         6 . Subsea well intervention module according to  claim 1 , further comprising a control system ( 126 ) for controlling the well manipulation assembly, the navigation means, the buoyancy system and the intervention operations. 
     
     
         7 . Subsea well intervention module according to  claim 6 , wherein the supporting structure is a frame structure having an outer form and defining an internal space containing a control system, the control system extending within the outer form. 
     
     
         8 . Subsea well intervention module according to  claim 1 , wherein the navigation means comprises at least one guiding arm for gripping around another structure in order to guide the module into place. 
     
     
         9 . Subsea well intervention module according to  claim 1 , wherein the navigation means comprises a detection means ( 109 ) for detection of a position of the intervention module. 
     
     
         10 . Subsea well intervention module according to  claim 1 , wherein the buoyancy system comprises:
 a displacement tank ( 130 ),   a control means ( 131 ) for controlling the filling of the tank, and   an expansion means ( 132 ) for expelling sea water from the displacement tank when providing buoyancy to the module to compensate for the weight of the intervention module itself in the water.   
     
     
         11 . Subsea well intervention module according to  claim 9 , wherein the detection means comprises at least one image recording means. 
     
     
         12 . Subsea well intervention module according to  claim 1 , wherein the well manipulation assembly comprises:
 a tool delivery system ( 170 ) comprising:
 at least one tool ( 171 ) for submersion into the well, and 
 a tool submersion means ( 172 ) for submerging the tool into the well through the well head, 
   at least one well head connection means ( 173 ) for connection to the well head, and   a well head valve control means ( 174 ) for operating at least a first well head valve ( 121 ) for providing access of the tool into the well through the well head connection means.   
     
     
         13 . Subsea well intervention module according to  claim 12 , wherein the tool delivery system comprises at least one driving unit for driving the tool forward in the well. 
     
     
         14 . Subsea well intervention module according to  claim 1 , wherein the well manipulation assembly comprises a cap removal means ( 134 ) for removal of a protective cap ( 123 ) on the well head. 
     
     
         15 . Subsea well intervention module according to  claim 1 , further comprising a power system ( 119 ) for supplying power to an intervention operation, such as a cable ( 106 ) from the surface vessel, a battery, a fuel cell, a diesel current generator, an alternator, a producer or the like power supplying means. 
     
     
         16 . Subsea well intervention module according to  claim 15 , wherein the power system comprises a power storage system ( 133 ) for storage of energy generated from an intervention operation, such as submersion of an operational tool ( 171 ) into the well. 
     
     
         17 . Subsea well intervention module according to  claim 15 , wherein the power system has an amount of reserve power stored in the power storage system large enough for allowing the control system to disconnect the well head connection means from the well head, the cable for providing power from the power system, the wireline from the intervention module, or the attachment means from the well head structure. 
     
     
         18 . Subsea well intervention module according to  claim 1 , wherein the supporting structure is, at least partly, made from hollow profiles. 
     
     
         19 . Subsea well intervention module according to  claim 18 , wherein the hollow profiles enclose a closure comprising a gas. 
     
     
         20 . Subsea well intervention system ( 200 ) comprising
 at least one subsea intervention module according to  claim 1 , and   at least one remotely operational vehicle for navigating the intervention module onto the well head or another module subsea.   
     
     
         21 . Subsea well intervention system according to  claim 20 , further comprising at least one remote control means ( 192 ) for remotely controlling some or all functionalities of the intervention module, the remote control means being positioned above water. 
     
     
         22 . Subsea well intervention system according to  claim 20 , further comprising
 at least one autonomous communication relay device ( 190 ) for receiving signals from the intervention module, converting the signals into airborne signals ( 191 ), and transmitting the airborne signals to the remote control means, and vice versa to receive and convert signals from the remote control means and transmit the converted signals to the intervention module.   
     
     
         23 . Subsea well intervention system according to  claim 1 , wherein the intervention module or parts of the intervention module are made from metals, such as steel or aluminium, or a light weight material weighing less than steel, such as polymers or a composite material, e.g. glass or carbon fibre reinforced polymers. 
     
     
         24 . Subsea well intervention method comprising the steps of:
 positioning a surface vessel in vicinity of the subsea well head,   connecting a subsea well intervention module to the wireline on the vessel,   dumping the subsea well intervention module into the water from the surface vessel by pushing the module over a side ( 103 ) or an end of the vessel,   controlling the navigation means on the intervention module,   manoeuvring the module onto the well head,   connecting the module to the well head,   controlling the control system to perform one or more intervention operations,   detaching the module from the well head after performing the operations, and   recovering the module onto the surface vessel by pulling in the wireline.   
     
     
         25 . Subsea well intervention method according to  claim 24 , further comprising the steps of:
 connecting a second subsea well intervention module to the wireline on the vessel,   dumping the second subsea well intervention module into the water from the surface vessel by pushing the module over a side or an end of the vessel before recovering the previous subsea intervention module.