Methods For Servicing Subterranean Wells

Abstract

Methods for curing lost circulation in a subterranean well comprise the use of a first and a second lost circulation material. The first lost circulation material is added during the initial preparation of a process fluid. The second process fluid is added to the process fluid at a later time as the process fluid is being pumped into the subterranean well. The first lost circulation may comprise granular or lamellar particles or both. The second lost circulation material may comprise fibers, ribbons or both.

1 . A method for treating lost circulation in a subterranean well, comprising:
 (i) preparing a process fluid comprising a first lost circulation material having a concentration;   (ii) placing the process fluid into one ore more subterranean lost circulation zones;   (iii) adding a second lost-circulation material having a concentration to the process fluid during placement on the fly.   
     
     
         2 . The method of  claim 1 , wherein the process fluid is a drilling fluid, a cement slurry, a spacer fluid, a chemical wash, a scavenger slurry, a completion fluid, a pill or a gravel packing fluid. 
     
     
         3 . The method of  claim 1 , wherein the first lost circulation material is granular, lamellar or both. 
     
     
         4 . The method of  claim 3 , wherein the first lost circulation material comprises mica. 
     
     
         5 . The method of  claim 1 , wherein the second lost circulation material has an aspect ratio between 10 and 1000. 
     
     
         6 . The method of  claim 5 , wherein the second lost circulation material is fibrous. 
     
     
         7 . The method of  claim 1 , wherein the second lost circulation material is added to a portion of the process fluid, added such that the concentration of the second lost circulation material is ramped up during placement, or added intermittently during placement. 
     
     
         8 . A method for cementing a subterranean well, comprising:
 (i) preparing a cement slurry comprising a first lost circulation material having a concentration;   (ii) placing the cement slurry into one or more subterranean lost circulation zones;   (iii) adding a second lost-circulation material having a concentration to the cement slurry during placement on the fly.   
     
     
         9 . The method of  claim 8 , wherein the first lost circulation material is granular, lamellar or both. 
     
     
         10 . The method of  claim 9 , wherein the first lost circulation material comprises mica. 
     
     
         11 . The method of  claim 8 , wherein the second lost circulation material has an aspect ratio between 10 and 1000. 
     
     
         12 . The method of  claim 11 , wherein the second lost circulation material is fibrous. 
     
     
         13 . The method of  claim 8 , wherein the second lost circulation material is added to a portion of the cement slurry, added such that the concentration of the second lost circulation material is ramped up during placement, or added intermittently during placement. 
     
     
         14 . A method for completing a subterranean well, comprising:
 (i) preparing a process fluid comprising a first lost circulation material having a concentration;   (ii) placing the process fluid into one or more subterranean lost circulation zones;   (iii) adding a second lost-circulation material having a concentration to the process fluid during placement on the fly.   
     
     
         15 . The method of  claim 14 , wherein the process fluid is a drilling fluid, a cement slurry, a spacer fluid, a chemical wash, a scavenger slurry, a completion fluid, a pill or a gravel packing fluid. 
     
     
         16 . The method of  claim 15 , wherein the first lost circulation material is granular, lamellar or both. 
     
     
         17 . The method of  claim 16 , wherein the first lost circulation material comprises mica. 
     
     
         18 . The method of  claim 14 , wherein the second lost circulation material has an aspect ratio between 10 and 1000. 
     
     
         19 . The method of  claim 18 , wherein the second lost circulation material is fibrous. 
     
     
         20 . The method of  claim 14 , wherein the second lost circulation material is added to a portion of the process fluid, added such that the concentration of the second lost circulation material is ramped up during placement, or added intermittently during placement.