Lng receiving terminal that primarily uses compensated salt cavern storage and method of use

Abstract

In the past, “compensated” salt caverns have operated with a compensating liquid, such as brine to displace a stored liquid, such as crude oil, when the stored liquid is needed on the surface. Virtually all of the stored liquid in a compensated salt cavern can be expelled from the salt cavern when it is filled with the compensating liquid. In the past, “uncompensated” salt caverns have been used to store gases, such as natural gas. Uncompensated caverns operate without any compensating liquid; instead they rely on pressure. Some of the stored gas (cushion gas) must always be left in an uncompensated salt cavern. This invention breaks with convention and uses a compensating liquid in a salt cavern to store gases which is a technique believed to be previously unknown. “Cushion gas” is not required because the compensating liquid displaces virtually all of the gas in the salt cavern.

1 . A compensated salt cavern based storage facility for natural gas comprising:
 at least one compensated salt cavern;   a source of natural gas selected from the group consisting of: an LNG receiving terminal, a natural gas pipeline and combinations thereof;   means for filling the compensated salt cavern with natural gas;   a storage facility for a compensating liquid; and   means for moving the compensating liquid into the at least one compensated salt cavern to draw down the natural gas from the compensated cavern.   
   
   
       2 . A compensated salt cavern based storage facility for natural gas comprising:
 at least one compensated salt cavern;   a source of natural gas selected from the group consisting of: an LNG receiving terminal, a natural gas pipeline and combinations thereof;   means for filling the compensated salt cavern with natural gas;   a pond for storage of a compensating liquid; and   means for moving the compensating liquid into and out of the at least one compensated salt cavern;   
   
   
       3 . A compensated salt cavern based storage facility for natural gas comprising:
 at least one compensated salt cavern;   a source of natural gas from at least one natural gas pipeline;   means for moving a compensating liquid into and out of the at least one compensated salt cavern;   at least one compressor to compress natural gas from the at least one pipeline source; and   at least one heat exchanger to cool the compressed natural gas to a temperature that is compatible with the compensated salt cavern, before the compressed natural gas is placed in the at least one compensated salt cavern for storage.   
   
   
       4 . The natural gas storage facility of  claim 3  further including:
 a second compensated salt cavern to store the compressed natural gas;   means for moving a compensating liquid into and out of the second compensated salt cavern;   a third compensated salt cavern to store and blend a portion of the natural gas from the first compensated salt cavern with a portion of the compressed natural gas from the second compensated salt cavern to adjust the Btu content of the blended fluids to conform to a pre-established pipeline standard; and   means for moving the compensating liquid into and out of the third compensated salt cavern.   
   
   
       5 . A method for operating a compensated salt cavern based natural gas storage facility comprising:
 filling a salt cavern with natural gas from a source of natural gas selected from the group consisting of: an LNG receiving terminal, a natural gas pipeline and combinations thereof; and   drawing down the natural gas in the salt cavern by pumping a compensating liquid from a storage pond into the salt cavern to displace the natural gas and force the natural gas into a pipeline for delivery to market.   
   
   
       6 . A method of storing natural gas in a compensated salt cavern based storage facility comprising:
 pumping a compensating liquid into at least one compensated salt cavern;   compressing natural gas from a pipeline;   cooling the compressed natural gas to a temperature that is compatible with the at least one compensated salt cavern; and   injecting the cooled, compressed natural gas into the at least one compensated salt cavern thereby displacing the compensating liquid from the compensated salt cavern into a storage pond.   
   
   
       7 . The method of  claim 6  further including:
 blending at least a portion of the warmed fluid from a first compensated salt cavern with at least a portion of the cooled, compressed natural gas from a second compensated salt cavern to adjust the Btu content of the blended fluids to conform to a pre-established pipeline standard.   
   
   
       8 . The method of  claim 6  further including:
 blending at least a portion of a dense phase natural gas from a first compensated salt cavern with at least a portion of the cooled, compressed natural gas from a second compensated salt cavern to adjust the Btu content of the blended fluids to conform to a pre-established pipeline standard.   
   
   
       9 . A method of storing natural gas in a compensated salt cavern based storage facility comprising:
 pumping a compensating liquid into the at least one compensated salt caver   compressing natural gas from a pipeline;   cooling the compressed natural gas to a temperature that is compatible with the at least one compensated salt cavern; and   storing the cooled, compressed natural gas in the at least one compensated salt cavern.   
   
   
       10 . The method of  claim 9  further including: maintaining the pressure of a dense phase natural gas in the at least one compensated salt cavern in the operating pressure range for the full compensation mode. 
   
   
       11 . The method of  claim 9  further including:
 raising the pressure of a dense phase natural gas in the at least one compensated salt cavern to allow operation in the partial compensation mode.   
   
   
       12 . A method for operating a compensated salt cavern based natural gas storage facility comprising:
 providing a source of natural gas selected from the group consisting of: an LNG receiving terminal, a pipeline and combinations thereof;   providing at least one compensated salt cavern;   filling the at least one compensated salt cavern with natural gas from the source and recovering a compensating liquid; and   removing at lest a portion of the natural gas from the at least one compensated salt cavern by pumping the compensating liquid into the salt cavern.   
   
   
       13 . A method for operating a compensated salt cavern based natural gas storage facility comprising:
 providing a source of natural gas from a pipeline;   providing at least one compensated salt cavern;   filling the at least one compensated salt cavern with natural gas and recovering a compensating liquid; and   removing at least a portion of the natural gas from the at least one compensated salt cavern by pumping the compensating liquid into the salt cavern.   
   
   
       14 . A method for converting an existing uncompensated salt cavern based natural gas storage facility into a compensated salt cavern based natural gas storage facility containing at least one salt cavern, the method comprising the following steps:
 drilling at least one well from the surface into the at least one salt cavern to a depth near the bottom of the at least on salt cavern for a compensating liquid;   building a holding pond sized to contain enough of a compensating liquid to substantially fill the at least one salt cavern in the existing natural gas storage facility; and   installing a pumping system, piping and controls for moving the compensating liquid between the at least one holding pond and the at least one salt cavern through the at least one well of the natural gas storage facility.   
   
   
       15 . The method of  claim 14  further including: drilling another well from the surface into the at least one salt cavern to a depth near the bottom of the at least one salt cavern. 
   
   
       16 . A method for operating a natural gas storage facility in at least one compensated salt cavern comprising the following steps: exchanging an equal volume of natural gas and compensating liquid when the at least one salt cavern is filled with natural gas and when the natural gas in drawdown from the at least one salt cavern. 
   
   
       17 . A method for operating a natural gas storage facility in at least one compensated salt cavern comprising the following steps:
 filling the at least one salt cavern by injecting a volume of natural gas equal to a volume of compensating liquid being displaced; and   drawing down the at least one salt cavern by injecting a volume of compensating liquid equal to the volume of natural gas being displaced.   
   
   
       18 . A method for operating a natural gas storage facility in at least one compensated salt cavern comprising the following steps:
 injecting natural gas into at least one salt cavern at a volumetric rate equal to that of a compensating liquid being displaced; and   injecting the compensating liquid into at least one salt cavern at a volumetric rate equal to the natural gas being displaced.   
   
   
       19 . A method for operating a natural gas storage facility in at least one compensated salt cavern comprising the following steps:
 injecting natural gas into at least one salt cavern at a volumetric rate that exceeds the rate at which a compensating liquid is being displaced;   injecting the compensating liquid into at least one salt cavern at a volumetric rate less than that of the natural gas being displaced to complete the draw down.   
   
   
       20 . A method for selecting the proper depth for a compensated salt cavern for storage of natural gas, the cavern discharging natural gas into a pipeline at or near the surface, the method comprising:
 selecting the depth of the salt cavern that will allow sufficient pressure to force the compensating liquid to a storage facility for the compensating liquid at a desired flow rate; and   selecting the depth of the salt cavern that will allow production of the gas at a pressure desired at the surface and at a desired flow rate.   
   
   
       21 . A method for selecting the proper depth of a compensated salt cavern for storage of natural gas, the cavern discharging natural gas into a pipeline at or near the surface, the method comprising:
 selecting the depth of the salt cavern that will allow sufficient pressure to force the compensating liquid to a storage facility for the compensating liquid at a desired flow rate; and   selecting the depth of the salt cavern that will allow storage of the natural gas at a pressure that is greater than that required at the surface.