System and vessel for hydrocarbon production and method for intervention on subsea equipment

Abstract

A system for operation and service of at least one hydrocarbon-producing well and of equipment, which is disposed under water, for further transport of the well stream, where the system comprises at least one pipeline, at least one booster unit, a vessel comprising an anchoring system about which the vessel can rotate or swivel, means for conducting an intervention on subsea equipment, means for communication with and control of the at least one well and other equipment, means for injecting chemicals into the well streams, means for transferring to and inserting pigs in the pipeline, means for production of energy for operation of subsea equipment, means for transferring energy from the means for production of energy to the booster unit and any other subsea equipment.

1 . A system for operation and service of at least one hydrocarbon-producing well and of equipment for further transport of the well stream and any equipment for treatment of the well stream, where said equipment and at least one well are disposed below a water surface, particularly on a seabed or an ocean floor, which system comprises:
 at least one pipeline for transport of the well stream to the desired destination,   at least one pressure booster unit for driveling the well stream through the at least one pipeline,   
     wherein the system further comprises
 a vessel for operation and service of the at least one well and the equipment disposed below the water surface, which vessel comprises
 an anchoring system comprising a mooring system, a dynamic positioning system or a combination of the two, and where the anchoring system is arranged in such a manner that the vessel can rotate about or swivel around the anchoring system, 
 means for conducting an intervention on equipment disposed below the water surface, 
 means for communication with and control of the at least one well and other equipment disposed below the water surface, 
 
 means for transferring chemicals from the vessel to the well streams and the at least one pipeline and means for injecting the chemicals into the well stream and the well stream in the pipeline, 
 means for inserting pigs in the at least one pipeline and means for transferring pigs from the vessel to the at least one pipeline, 
 means for production of energy for operation of equipment disposed below the water surface, 
 means for transferring energy from the means for production of energy to the at least one pressure booster unit and any other subsea equipment. 
 
   
   
       2 . A system according to  claim 1 , wherein at least one pressure booster unit is mounted at each well. 
   
   
       3 . A system according to  claim 1 , wherein the system comprises a pressure booster station where the well streams from the hydrocarbon-producing wells are collected and pressurised and from which at least one pipeline is provided for further transport of the well streams to the desired destination. 
   
   
       4 . A system according to  claim 1 , wherein equipment disposed below the water surface is preferably arranged below and within the curve described by the vessel's outer point as the vessel rotates about or swivels around the anchoring system. 
   
   
       5 . A system according to  claim 1 , wherein the means for production of energy for operation of equipment disposed below the water surface is either provided in its entirety on the vessel or in its entirety below the water surface. 
   
   
       6 . A system according to  claim 1 , wherein parts of the means for production of energy for operation of equipment disposed below the water surface is provided on the vessel, while the rest of the means are provided below the water surface. 
   
   
       7 . A system according to  claim 1 , wherein the system is provided with means for removing a part of the gas in the well stream as well as means for transporting the gas to means for production of energy. 
   
   
       8 . A system according to  claim 7 , wherein the means for producing the energy for operation of equipment and the at least one well which are disposed below the water surface also comprise a processing plant adapted for processing the gas removed from the well stream for operation of the power generating unit. 
   
   
       9 . A system according to  claim 1 , wherein the vessel is provided with storage capacity for necessary contributing factors in connection with operation and maintenance of the system, such as chemicals for injecting into the well stream, pigs and equipment for launching and receiving pigs, spare parts and equipment for use in intervention on equipment below the water surface, and possibly fuel required for energy production. 
   
   
       10 . A system according to  claim 1 , wherein the system comprises heating means (for heating the at least one pipeline, and means (for transferring necessary energy from the means for production of energy to the heating means. 
   
   
       11 . A system according to  claim 1 , wherein the system also comprises additional equipment for treatment of the well stream disposed below the water surface, and particularly on the seabed or ocean floor, such as equipment for mixing, desanding and water separation. 
   
   
       12 . A system according to  claim 1 , wherein the system comprises means for communicating production and control data from the at least one well and other equipment, which is disposed below the water surface, to the vessel. 
   
   
       13 . A system according to  claim 1 , wherein the system comprises means for transmitting control signals from the vessel to the at least one well and other equipment disposed below the water surface. 
   
   
       14 . A vessel for operation and maintenance in connection with production of a well stream containing hydrocarbons from at least one well and maintenance of production equipment and equipment for further transport of the well stream, where the at least one well and the equipment are disposed below the water surface, particularly on a seabed or an ocean floor, wherein the vessel further comprises:
 a system for anchoring comprising a mooring system or a dynamic positioning system or a combination of the two, which anchor is arranged in such a manner that the vessel can rotate about or swivel around the said anchor,   means for transferring chemicals to at least one pipeline disposed below the water surface,   storage space for storing chemicals that are to be injected into the pipeline,   means for conducting an intervention on equipment disposed below the water surface,   storage space for storing equipment for use in intervention on equipment below the water surface and spare parts for said equipment below the water surface,   means for transferring pigs to a pipeline disposed below the water surface,   storage space for storing pigs and equipment for transferring pigs to the pipeline.   
   
   
       15 . A vessel according to  claim 14 , wherein the vessel is arranged in such a manner that it can be disconnected from the anchor as well as communication line(s), umbilical(s) and other devices connecting the vessel to the at least one well and the equipment disposed below the water surface. 
   
   
       16 . A vessel according to,  claim 14 , wherein the vessel comprises means for production of energy for operation of equipment disposed below the water surface, as well as any heating of at least one pipeline disposed below the water surface. 
   
   
       17 . A vessel according to  claim 16 , wherein a part of the means for production of energy is provided on the vessel, while the rest of the means are provided below the water surface. 
   
   
       18 . A vessel according to,  claim 14 , wherein the means for producing energy comprise at least one generator set. 
   
   
       19 . A vessel according to  claim 18 , wherein the vessel comprises fuel tanks for fuel required for operation of the at least one generator set. 
   
   
       20 . A vessel according to  claim 14 , wherein the vessel comprises means for transferring the produced energy from the vessel to subsea equipment and possibly the at least one pipeline. 
   
   
       21 . A method for intervention on equipment in use in connection with production of a well stream containing hydrocarbons from at least one well and equipment for further transport of the well stream, where said equipment is disposed below a water surface, particularly on a seabed or ocean floor, and where the intervention is conducted from a vessel for operation and maintenance of equipment disposed below the water surface, where the vessel is arranged in such a manner that it can rotate about or swivel round its anchoring system, and which vessel comprises means for conducting an intervention on subsea equipment disposed below the water surface, and means for lowering a tool system and any spare parts down to the subsea equipment, 
     wherein
 the operating and service vessel is positioned in such a manner that means for lowering a tool system and any spare parts are located substantially over the subsea equipment, 
 the operating and service vessel may be disconnected from its anchoring system as well as communication line(s), umbilical(s) and other devices connecting the vessel to one or more wells and equipment disposed below the water surface, thus enabling it to be positioned over the subsea equipment, 
 the tool system and any spare parts are lowered down to the subsea equipment, necessary service or repair is carried out on the subsea equipment, 
 if necessary, both service and repair are carried out on the subsea equipment, 
 the tool system is lifted up to the operating and service vessel.