Enhanced system for sand cleaning in a hydrocyclone

Abstract

The invention relates to a system ( 100 ) for the cleaning of sand, originating from subterranean oil production and comprises separation of sand from adhering oil out of a sand/oil/water slurry. The sand is cleaned through treatment in a hydrocyclone ( 13 ) through rubbing against themselves and the walls of the hydrocyclone. The hydrocyclone discharges the larger/heavier particles into a vessel ( 1 ), wherein the vessel has a discharge port ( 3 ) for the sand. A fluid extractor ( 34 ) is provided between the hydrocyclone ( 13 ) and the discharge port of the vessel ( 1 ), for extracting fluid from the vessel ( 1 ) to permit an increased flow rate of sand into the vessel. The invention also relates to a method of cleaning sand and a method of increasing the flow rate of sand through a hydrocyclone cleaning system as described above.

1 . A cleaning system for hydrocyclone sand cleaning, comprising:
 a hydrocyclone for receiving a slurry containing sand to be cleaned;   a vessel for receiving sand exiting the hydrocyclone and having a sand discharge port for permitting sand to be discharged from the vessel; and   a fluid extraction arrangement configured for extracting fluid from the vessel at a location between the hydrocyclone and the sand discharge port to permit an increased flow rate of sand into the vessel.   
     
     
         2 . The cleaning system according to  claim 1 , wherein the fluid extraction arrangement comprises or defines an extraction port located between the hydrocyclone and the sand discharge port. 
     
     
         3 . The cleaning system according to  claim 2 , wherein the extraction port is located above an expected maximum level of sand when it has accumulated in the vessel. 
     
     
         4 . The cleaning system according to  claim 2 , wherein the extraction port is provided in an upper portion of the vessel. 
     
     
         5 . The cleaning system according to  claim 2 , wherein the extraction port is formed or provided on a wall of the vessel. 
     
     
         6 . The cleaning system according to  claim 2 , wherein the extraction port is defined within the vessel. 
     
     
         7 . The cleaning system according to  claim 1 , wherein the fluid extraction arrangement comprises an extraction conduit system extending from the vessel. 
     
     
         8 . The cleaning system according to  claim 1 , wherein the fluid extraction arrangement is configured to discharge at least a portion of fluid extracted from the vessel from the cleaning system. 
     
     
         9 . The cleaning system according to  claim 1 , wherein the fluid extraction arrangement is configured to recycle at least a portion of fluid extracted from the vessel within the cleaning system. 
     
     
         10 . The cleaning system according to  claim 9 , wherein the fluid extraction arrangement is configured to feed extracted fluid into the sand slurry prior to or on entry of the slurry into the hydrocyclone. 
     
     
         11 . The cleaning system according to  claim 1 , wherein the fluid extraction arrangement is configured to permit passive extraction of fluid from the vessel. 
     
     
         12 . The cleaning system according to  claim 1 , wherein the fluid extraction arrangement is configured to permit active extraction of fluid from the vessel. 
     
     
         13 . The cleaning system according to  claim 1 , wherein the fluid extraction arrangement comprises flow control equipment configured to draw fluid from the vessel. 
     
     
         14 . The cleaning system according to  claim 1 , wherein the fluid extraction arrangement comprises a fluid drive apparatus or means. 
     
     
         15 . The cleaning system according to  claim 1 , wherein the fluid extraction arrangement comprises a dedicated fluid drive apparatus or means provided exclusively for use in actively extracting fluid from the vessel. 
     
     
         16 . The cleaning system according to  claim 1 , wherein the fluid extraction arrangement comprises or utilises a shared fluid drive apparatus or means. 
     
     
         17 . The cleaning system according to  claim 14 , wherein the fluid drive apparatus or means defines an inlet configured to receive or extract fluid from the vessel, and an outlet configured to at least one of discharge fluid from the cleaning system and recycle fluid within the cleaning system. 
     
     
         18 . The cleaning system according to  claim 1 , wherein the fluid extraction arrangement comprises an eductor defining a suction port in fluid communication with the vessel. 
     
     
         19 . The cleaning system according to  claim 18 , wherein the eductor defines a motive fluid port in fluid communication with a motive fluid source. 
     
     
         20 . The cleaning system according to  claim 19 , wherein the motive fluid port is configured to receive fluid from the hydrocyclone. 
     
     
         21 . The cleaning system according to  claim 1 , wherein the fluid extractor arrangement comprises a pump. 
     
     
         22 . The cleaning system according to  claim 1 , further comprising a sand extraction arrangement configured for use in extracting sand from the vessel via the sand discharge port. 
     
     
         23 . The cleaning system according to  claim 22 , wherein the sand extraction arrangement comprises a drive apparatus or means in communication with the sand discharge port. 
     
     
         24 . The cleaning system according to  claim 23 , wherein the drive apparatus or means of the sand extraction arrangement is associated with the fluid extraction arrangement and is configured for both extracting fluid as a function of the fluid extraction arrangement, and extracting sand as a function of the sand extraction arrangement. 
     
     
         25 . The cleaning system according to  claim 22 , wherein the sand extraction arrangement comprises an eductor or a pump arranged to extract sand through the discharge port of the vessel. 
     
     
         26 . The cleaning system according to  claim 22 , wherein a fluid input is provided to assist the flow of sand through the sand extraction arrangement. 
     
     
         27 . The cleaning system according to  claim 26 , wherein the fluid input is connected to an external fluid supply, an overflow port of the hydrocyclone and/or a discharge or output of the fluid extractor arrangement. 
     
     
         28 . The cleaning system according to  claim 27 , wherein a fluid treatment device is connected to the fluid input to clean fluid flowing from the external fluid supply, the overflow port of the hydrocyclone and/or the fluid extractor arrangement. 
     
     
         29 . The cleaning system according to  claim 1 , wherein the vessel is configured to define a region containing a mix of solids and liquids, and a region containing predominantly liquids. 
     
     
         30 . The cleaning system according to  claim 29 , wherein sand exiting the hydrocyclone is received directly into the region containing predominantly liquids. 
     
     
         31 . The cleaning system according to  claim 1 , wherein the vessel is configured to define only a region containing a mix of solids and liquids and a region containing predominantly liquids. 
     
     
         32 . A method for use in cleaning sand, comprising:
 feeding a slurry containing sand to be cleaned into a hydrocyclone;   allowing sand to exit the hydrocyclone into a vessel below, the vessel having an discharge port for the sand; and   extracting fluid from the vessel from a position between the hydrocyclone and the discharge port to permit an increased flow rate of sand into the vessel.   
     
     
         33 . The method according to  claim 32 , wherein the fluid is extracted from an upper portion of the vessel. 
     
     
         34 . The method according to  claim 32 , further comprising diluting the slurry prior to or on feeding the slurry into the hydrocyclone. 
     
     
         35 . The method according to  claim 34 , wherein the slurry is diluted by the extracted fluid. 
     
     
         36 . The method according to  claim 32 , employed in a cleaning system according to  claim 1 , when operating in one or more of a collecting mode, a cleaning mode or a discharge mode.