Choke for controlling the flow of drilling mud

Abstract

A drilling system and method for drilling a well bore in to an earth formation is provided with drilling means for drilling a well bore and pumping means for pumping drilling fluid into the wellbore during drilling. Also provided is a drilling outlet system for retrieving drilling fluid from the well bore. The drilling fluid outlet system has choke means for choking the return flow of retrieved drilling fluid, and alternating means for alternating the flow direction through the choking means.

1 . A drilling system for drilling a well bore into an earth formation, comprising: 
 drilling means for drilling a well bore;    pumping means for pumping drilling fluid into the well bore during drilling; and    a drilling fluid outlet system for retrieving drilling fluid from the well bore, said drilling fluid outlet system comprising a choke means for choking the return flow of retrieved drilling fluid, and alternating means for alternating the flow direction through the choking means.    
   
   
       2 . The drilling system according to  claim 1 , wherein the drilling fluid outlet system comprises an accumulator.  
   
   
       3 . The drilling system according to  claim 2 , wherein the alternating means comprise a four way valve, having four connections and wherein the connections are connected two by two.  
   
   
       4 . The drilling system according to  claim 2 , wherein the choking means comprise a bidirectional choke.  
   
   
       5 . The drilling system according to  claim 1 , wherein the choking means comprise at least two unidirectional chokes.  
   
   
       6 . The drilling system according to  claim 5 , wherein the alternating means comprise a four way valve, having four connections and wherein the connections are connected two by two.  
   
   
       7 . The drilling system according to  claim 1 , wherein the alternating means comprise a four way valve, having four connections connected two by two, and wherein the choking means comprise a bi-directional choke.  
   
   
       8 . The drilling system according to  claim 1 , wherein wherein the drilling fluid outlet system comprises an inlet and an outlet, the choke means comprise a first inlet/outlet connection, a second outlet/inlet connection, and the alternating means connect the inlet alternatingly to the first or second connection and the outlet alternatingly to the second or first connection and wherein the alternating means comprise a four way valve, having four connections and wherein the connections are connected two by two.  
   
   
       9 . The drilling system according to  claim 1 , wherein wherein the drilling fluid outlet system comprises an inlet and an outlet, the choke means comprise a first inlet/outlet connection, a second outlet/inlet connection, and the alternating means connect the inlet alternatingly to the first or second connection and the outlet alternatingly to the second or first connection and wherein the alternating means comprise a four way valve, having four connections connected two by two, and wherein the choking means comprise a bi-directional choke.  
   
   
       10 . A drilling fluid outlet system connectable to a well bore for receiving a return flow of drilling mud retrieved from the well bore and discharging the drilling mud into a reservoir, the drilling fluid outlet system comprising a choke means for choking the return flow of retrieved drilling fluid, and alternating means for alternating the flow direction through the choking means.  
   
   
       11 . The drilling fluid outlet system according to  claim 10 , wherein the drilling fluid outlet system comprises an inlet and an outlet, the choke means comprise a first inlet/outlet connection, a second outlet/inlet connection, and the alternating means connect the inlet alternatingly to the first or second connection and the outlet alternatingly to the second or first connection.  
   
   
       12 . The drilling fluid outlet system according to  claim 11 , wherein filter means are arranged in the first and second connection of the choke means.  
   
   
       13 . The drilling fluid outlet system according to  claim 10 , wherein the alternating means comprise a four way valve, having four connections and wherein the connections are connected two by two.  
   
   
       14 . The drilling fluid outlet system according to  claim 10 , wherein the drilling fluid outlet system comprises an accumulator.  
   
   
       15 . The drilling fluid outlet system according to  claim 10 , wherein the choking means comprise a bi-directional choke.  
   
   
       16 . The drilling fluid outlet system according to  claim 10 , wherein the choking means comprise at least two unidirectional chokes.