Method and apparatus for collecting and then disposing sand contained in production fluid

Abstract

Production fluid mixture is directed through a sand removal unit ( 12 ) in a retrievable module ( 1 ) installed in a modular seabed processing system, and the unit ( 12 ) collects sand from the mixture. The production fluid mixture then enters a fluid separation chamber ( 17 ) in the module ( 1 ) where it is separated into a gas and a mixture of oil and water. Seawater is drawn in from outside the module and is pumped into the sand removal unit ( 12 ) to flush the collected sand. The mixed flushed sand and seawater is commingled with the mixture of oil and water downstream of the fluid separation chamber ( 17 ) and the commingled mixture is conveyed to a host facility. There, the sand is separated from the commingled mixture and is disposed of.

1 . A method for collecting sand contained in production fluid and disposing of the collected sand, comprising the steps of: 
 flowing production fluid through sand removal means ( 12 ) and collecting sand from the production fluid in the sand removal means;    supplying flushing fluid for flushing the sand removal means ( 12 );    flushing sand from the sand removal means ( 12 ) with the flushing fluid; and    directing the mixed flushed sand and flushing fluid away from production fluid processing means ( 17 ) located downstream of the sand removal means ( 12 ).    
   
   
       2 . A method as claimed in  claim 1 , including commingling the mixed flushed sand and flushing fluid with production fluid from the production fluid processing means ( 17 ) downstream of the production fluid processing means.  
   
   
       3 . A method as claimed in  claim 2 , including the additional steps of conveying the commingled production fluid, flushed sand and flushing fluid to a host facility, and separating the flushed sand from the production fluid.  
   
   
       4 . A method as claimed in  claim 1 , including the additional steps of cleaning the mixed flushed sand and flushing fluid directed away from the production fluid processing means ( 17 ), and disposing of the cleaned sand and cleaned flushing fluid.  
   
   
       5 . A method as claimed in  claim 4 , wherein the cleaned sand and cleaned flushing fluid are at least partially disposed of into the surrounding environment.  
   
   
       6 . A method as claimed in  claim 5 , wherein the cleaned sand and cleaned flushing fluid are at least partially disposed of into at least one cavity below the surface of ground underneath water.  
   
   
       7 . A method as claimed in  claim 6 , wherein the flushing fluid is supplied from environmental water or water surrounding the sand removal means ( 12 ).  
   
   
       8 . A method as claimed in  claim 1 , including diverting at least some of the production fluid from downstream of the sand removal means ( 12 ), and flushing sand from the sand removal means with said diverted production fluid.  
   
   
       9 . A method as claimed in  claim 6 , wherein the production fluid processing means comprises fluid separation means ( 17 ) and the flushing fluid is supplied from the fluid separation means ( 17 ) wherein the flushing fluid comprises a fluid separated by the fluid separation means ( 17 ).  
   
   
       10 . A method as claimed in  claim 6 , wherein the flushing fluid is supplied from a host facility.  
   
   
       11 . A method as claimed in  claim 10 , wherein the flushing fluid is supplied from the host facility via a reservoir ( 53 ).  
   
   
       12 . A method as claimed in  claim 11 , wherein the flushing fluid from the reservoir ( 53 ) is pressure boosted by a pump ( 61 ).  
   
   
       13 . A method as claimed in  claim 13 , including the step of pressure boosting the supplied flushing fluid before the flushing fluid enters the sand removal means ( 12 ).  
   
   
       14 . An apparatus for collecting sand contained in production fluid and disposing of the collected sand, comprising: 
 sand removal means ( 12 ) for removing sand from the production fluid;    flushing means ( 39 ) for flushing sand from the sand removal means ( 12 ) with a flushing fluid; and    means for directing the mixed flushed sand and flushing fluid away from production fluid processing means ( 17 ) located downstream of said sand removal means ( 12 ).    
   
   
       15 . An apparatus as claimed in  claim 14 , including commingling means ( 90 ) downstream of the production fluid processing means ( 17 ) for commingling production fluid processed by said processing means with the mixed flushed sand and flushing fluid.  
   
   
       16 . An apparatus as claimed in  claim 14 , including cleaning means ( 44 ) for cleaning the mixed flushed sand and flushing fluid directed away from the production fluid processing means ( 17 ) before disposal of the sand and flushing fluid.  
   
   
       17 . An apparatus as claimed in  claim 16 , including means ( 45 , 46 ) for conveying the cleaned sand and flushing fluid into the environment surrounding the apparatus.  
   
   
       18 . An apparatus as claimed in  claim 14 , including a reservoir ( 53 ) for supplying the flushing fluid.  
   
   
       19 . An apparatus as claimed in  claim 17 , including means ( 64 , 65 , 66 ) for returning at least some of the production fluid downstream of the sand removal means ( 12 ) into the sand removal means, wherein the flushing fluid comprises the returned production fluid.  
   
   
       20 . An apparatus as claimed in  claim 19 , including said production fluid processing means ( 17 ).  
   
   
       21 . An apparatus as claimed in  claim 20 , wherein the production fluid processing means comprises fluid separation means ( 17 ).  
   
   
       22 . An apparatus as claimed in  claim 21 , including an outlet ( 20 ) from the fluid separation means ( 17 ) connected to the sand removal means ( 12 ) to enable the flushing fluid to comprise a fluid separated by the fluid separation means.  
   
   
       23 . An apparatus as claimed in  claim 22 , including a pump ( 39 ) for pressure boosting the flushing fluid before the flushing fluid enters the sand removal means ( 12 ).  
   
   
       24 . A retrievable production fluid processing module ( 1 ) for a seabed processing system, the module comprising the apparatus as claimed in  claim 23 , including a fluid connection means ( 2 ) for connection with the seabed system, wherein fluid to be processed by the production fluid processing means enters the module ( 1 ) via the fluid connection means ( 2 ) and fluid processed by the production fluid processing means ( 17 ) leaves the module via the fluid connection means ( 2 ).