Method for designing corrosion resistant alloy tubular strings

Abstract

A method to design an oilfield tubular string for a well includes determining the corrosiveness of fluids in the well and selecting an alloy for the oilfield tubular string, such that a corrosion resistance and a yield strength of the alloy may be varied through a heat treatment process, heat treating the alloy to survive the determined well fluid corrosiveness and determining the yield strength of the heat treated alloy, and selecting a diameter, a wall thickness, and a connection type for the oilfield tubing string based on the determined yield strength.

1 . A method to design an oilfield tubular string for a well, the method comprising: 
 determining the corrosiveness of fluids in the well;    selecting an alloy for the oilfield tubular string, wherein a corrosion resistance and a yield strength of the alloy may be varied through a heat treatment process;    heat treating the alloy to survive the determined well fluid corrosiveness;    determining the yield strength of the heat treated alloy; and    selecting a diameter, a wall thickness, and a connection type for the oilfield tubing string based on the determined yield strength.    
   
   
       2 . The method of  claim 1 , wherein the determined corrosiveness includes an acidity of the fluids in the well.  
   
   
       3 . The method of  claim 1 , further comprising maximizing the flow of well fluids through the oilfield tubular string with the selected diameter, wall thickness, and connection type.  
   
   
       4 . The method of  claim 1 , further comprising minimizing the oilfield tubular string weight with the selected diameter, wall thickness, and connection type.  
   
   
       5 . The method of  claim 1 , further comprising testing the survivability of the alloy at the determined corrosiveness of fluids in the well using a NACE “D” test.  
   
   
       6 . The method of  claim 1 , further comprising measuring the yield strength of the heat treated alloy with a hardness test.  
   
   
       7 . The method of  claim 1 , wherein the connection type is selected from the group consisting of non-upset, API upset, IEUE upset, threaded and coupled, and premium threaded connections.  
   
   
       8 . The method of  claim 1 , wherein the selected alloy comprises a corrosion resistant alloy.  
   
   
       9 . The method of  claim 8 , wherein the corrosion resistant alloy comprises martensitic stainless steel alloy selected from the group consisting of A-21 steel and 13Cr steel.  
   
   
       10 . A method to design an oilfield tubular string for a well, the method comprising: 
 determining a corrosiveness of fluids in the well;    specifying a maximum outer diameter of the oilfield tubular string;    selecting a alloy for the oilfield tubular string, wherein a corrosion resistance and a yield strength of the alloy may be varied through a heat treatment process;    heat treating the alloy to survive the determined well fluid corrosiveness;    determining the yield strength for the heat-treated alloy; and    selecting a wall thickness for the oilfield tubular string based upon the determined yield strength.    
   
   
       11 . The method of  claim 10 , wherein the determined corrosiveness includes an acidity of the fluids in the well.  
   
   
       12 . The method of  claim 10 , further comprising testing the survivability of the alloy at the determined corrosiveness using a NACE “D” test.  
   
   
       13 . The method of  claim 10 , further comprising minimizing the oilfield tubular string weight with the selected wall thickness.  
   
   
       14 . The method of  claim 10 , wherein the selected alloy comprises a corrosion resistant alloy.  
   
   
       15 . The method of  claim 14 , wherein the corrosion resistant alloy comprises martensitic stainless steel alloy selected from the group consisting of A-21 steel and 13Cr steel.  
   
   
       16 . A method to design an oilfield tubular string for a well, the method comprising: 
 determining a corrosiveness of fluids in the well;    selecting an alloy for the oilfield tubular string, wherein a corrosion resistance and a yield strength of the alloy may be varied through a heat treatment process;    performing a heat treatment on the selected alloy, wherein the heat treatment enables the alloy to exhibit a desired yield strength;    determining the corrosion resistance of the heat treated alloy;    buffering the fluids in the well such that the corrosion resistance of the heat treated alloy is sufficient to survive the corrosiveness of the buffered fluids in the well.    
   
   
       17 . The method of  claim 16 , wherein the determined corrosiveness includes an acidity of the fluids in the well.  
   
   
       18 . The method of  claim 16 , further comprising testing the corrosion resistance of the alloy at the determined corrosiveness using a NACE “D” test.  
   
   
       19 . The method of  claim 16 , wherein the selected alloy comprises a corrosion resistant alloy.  
   
   
       20 . The method of  claim 19 , wherein the corrosion resistant alloy comprises martensitic stainless steel alloy selected from the group consisting of A-21 steel and 13Cr steel.  
   
   
       21 . A method to design an oilfield tubular string for a well, the method comprising: 
 determining the corrosiveness of fluids in the well;    selecting an alloy for the oilfield tubular string, wherein a corrosion resistance and a yield strength of the alloy may be varied through a heat treatment process;    determining the yield strength of selected alloy at the determined corrosiveness;    heat treating the alloy to obtain the determined yield strength; and    selecting a diameter, a wall thickness, and a connection type for the oilfield tubing string based on the determined yield strength.    
   
   
       22 . The method of  claim 21 , further comprising maximizing the flow of well fluids through the oilfield tubular string with the selected diameter, wall thickness, and connection type.  
   
   
       23 . The method of  claim 21 , further comprising minimizing the oilfield tubular string weight with the selected diameter, wall thickness, and connection type.