Unit for treating a drilling mud and corresponding method

Abstract

A drilling mud treatment unit ( 100 ) comprises a primary duct ( 10 ) for feeding coagulated drilling mud, an in-line flocculation system ( 20 ) for flocculating the coagulated drilling mud flowing in the primary duct ( 10 ), and at least one hydrocyclone ( 30 ) fed by the primary duct ( 10 ) and arranged downstream from the flocculation system ( 20 ). The hydrocyclone ( 30 ) has an overflow orifice ( 32 ) for receiving a liquid product resulting from treatment of the drilling mud and an underflow orifice ( 34 ) for receiving a solid product resulting from treatment of the drilling mud. The overflow orifice ( 32 ) presents an overflow diameter (Do) and the underflow orifice presents an underflow diameter (Du), and the underflow diameter (Du) is greater than 1.1 times the overflow diameter (Do).

What is claimed is: 
     
         1 - 10 . (canceled) 
     
     
         11 . A drilling mud treatment unit comprising:
 a primary duct for feeding previously coagulated drilling mud;   an in-line flocculation system for flocculating the previously coagulated drilling mud flowing in the primary duct; and   at least one hydrocyclone fed by the primary duct and arranged downstream from the flocculation system, the hydrocyclone having an overflow orifice for receiving a liquid product resulting from treatment of the drilling mud and an underflow orifice for receiving a solid product resulting from treatment of the drilling mud, the overflow orifice presenting an overflow diameter and the underflow orifice presenting an underflow diameter, and the underflow diameter being greater than the overflow diameter, with a ratio greater than 1.1 between the underflow diameter and the overflow diameter.   
     
     
         12 . The treatment unit according to  claim 11 , wherein the primary feed duct is provided with a pump, and the in-line flocculation system includes a secondary duct for feeding flocculating agent, said secondary duct being connected to the primary duct at a junction situated downstream from the pump. 
     
     
         13 . The treatment unit according to  claim 12 , wherein the in-line flocculation system comprises an in-line mixer for mixing the coagulated drilling mud and the flocculating agent, the in-line mixer being provided in the primary duct downstream from the junction. 
     
     
         14 . The treatment unit according to  claim 13 , wherein the in-line mixer comprises a static mixer. 
     
     
         15 . The treatment unit according to  claim 13 , wherein the in-line mixer is arranged at a distance from the hydrocyclone in the primary duct that is shorter than 5 m. 
     
     
         16 . A treatment method for treating drilling mud, the method comprising at least the following succession of steps:
 feeding a primary feed duct with coagulated drilling mud;   flocculating the coagulated drilling mud in-line while it is flowing in the primary feed duct;   introducing the coagulated and flocculated drilling mud into a hydrocyclone having an overflow orifice presenting an overflow diameter, and an underflow orifice presenting an underflow diameter, the underflow diameter being greater than the overflow diameter, with a ratio greater than 1.1 between the underflow diameter and the overflow diameter; and   discharging a solid product resulting from treatment of the drilling mud via the underflow orifice, and a liquid product resulting from treatment of the drilling mud via an overflow orifice.   
     
     
         17 . The treatment method according to  claim 16 , wherein the drilling mud includes a stabilizing agent such as, for example, smectic clay or a hydrosoluble organic polymer. 
     
     
         18 . The treatment method according to  claim 16 , wherein the solid product of treating the drilling mud presents dryness greater than 30%. 
     
     
         19 . The treatment method according to  claim 16 , wherein the liquid product of treating the drilling mud is water containing less than 600 milligrams per liter of matter in suspension. 
     
     
         20 . The treatment method according to  claim 16 , wherein the primary duct is fed with previously coagulated drilling mud under turbulent conditions.