US2015376491A1PendingUtilityA1

Lost circulation composition for fracture sealing

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Assignee: HALLIBURTON ENERGY SERVICES INCPriority: Mar 1, 2013Filed: Oct 21, 2013Published: Dec 31, 2015
Est. expiryMar 1, 2033(~6.6 yrs left)· nominal 20-yr term from priority
Inventors:Matthew L. MillerJason T. ScorsoneDonald L. Whitfill
C09K 8/487C04B 28/26E21B 21/003C09K 2208/08C09K 2208/04E21B 33/138C04B 28/14Y02W30/91
56
PatentIndex Score
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Claims

Abstract

A lost circulation material and method for well treatment employing the material that is effective at sealing or plugging fractured zones and has utility over a wide range of temperatures, including high temperatures. The lost circulation material includes particulate material to quickly de-fluidize the fluid formulation, fibrous material to suspend particles in the slurrified form of the composition and increase the shear strength of the resultant seal, and non-Portland cement material for increasing the compressive strength.

Claims

exact text as granted — not AI-modified
What is claimed is: 
     
         1 . A lost circulation material composition, comprising:
 particulate material;   fibrous material comprising synthetic chopped fibers selected from the group consisting of polyacrylonitrile fibers and acrylonitrile/methyl acrylate fibers; and   non-Portland cement material.   
     
     
         2 . The lost circulation material composition of  claim 1 , wherein the particulate material is selected from the group consisting of diatomaceous earth, graphitic material and ground cellulosic material. 
     
     
         3 . The lost circulation material composition of  claim 2 , wherein the ground cellulosic material is selected from the group consisting of ground nut shells and ground fibrous cellulosic material. 
     
     
         4 . The lost circulation material composition of  claim 3 , wherein the ground nut shells are selected from the group consisting of walnut shells, peanut shells, almond shells, cashew shells, brazil nut shells, chestnut shells, pistachio shells and pecan shells. 
     
     
         5 . The lost circulation material composition of  claim 3 , wherein the ground nut shells are selected from the group consisting of walnut shells and pecan shells. 
     
     
         6 . The lost circulation material composition of  claim 1 , wherein the synthetic chopped fibers have an average length of from about 0.5 to 13 millimeters. 
     
     
         7 . The lost circulation material composition of  claim 6 , wherein the synthetic chopped fibers have an average length of from about 1 to 6 millimeters. 
     
     
         8 . The lost circulation material composition of  claim 6 , wherein the synthetic chopped fibers have an average length of about 3 millimeters. 
     
     
         9 . The lost circulation material composition of  claim 6 , wherein the synthetic chopped fibers have an average length of about 6 millimeters. 
     
     
         10 . The lost circulation material composition of  claim 6 , wherein the synthetic chopped fibers have a dtex of 3.3. 
     
     
         11 . The lost circulation material composition of  claim 1 , wherein the non-Portland cement material comprises a cement set accelerator. 
     
     
         12 . The lost circulation material composition of  claim 11 , wherein the cement set accelerator is selected from the group consisting of calcium sulfate hemihydrate and sodium metasilicate. 
     
     
         13 . The lost circulation material composition of  claim 1 , comprising:
 45 to 60 weight percent of diatomaceous earth;   5 to 15 weight percent of graphitic material;   5 to 15 weight percent of ground nut shells;   5 to 15 weight percent of ground fibrous cellulosic material;   5 to 15 weight percent of synthetic chopped fibers;   10 to 20 weight percent of calcium sulfate hemihydrate; and   2 to 12 weight percent of sodium metasilicate.   
     
     
         14 . The lost circulation material composition of  claim 1 , wherein the lost circulation material forms an unweighted filter cake having a shear strength of up to about 1325 psi at room temperature. 
     
     
         15 . The lost circulation material composition of  claim 1 , wherein the lost circulation material forms an unweighted filter cake having a shear strength per dtex of the synthetic chopped fibers of up to about 1366 psi/dtex at room temperature. 
     
     
         16 . The lost circulation material composition of  claim 1 , further comprising a weighting material, wherein the weighting material is selected from the group consisting of barite, salt and calcium carbonate. 
     
     
         17 . The lost circulation material composition of  claim 16 , wherein the lost circulation material forms a 12.0 lb/gal filter cake having a shear strength of up to about 420 psi at room temperature. 
     
     
         18 . The lost circulation material composition of  claim 16 , wherein the lost circulation material forms a 12.0 lb/gal filter cake having a shear strength per dtex of the synthetic chopped fibers of up to about 432 psi/dtex at room temperature. 
     
     
         19 . A method of sealing a fracture within a subterranean formation, comprising:
 preparing a lost circulation material composition comprising:
 particulate material; 
 fibrous material comprising synthetic chopped fibers selected from the group consisting of polyacrylonitrile fibers and acrylonitrile/methyl acrylate fibers; and 
 non-Portland cement material; 
   mixing the lost circulation material composition with a carrier fluid; and   contacting the lost circulation material composition with the subterranean formation such that the lost circulation material composition forms a sealing mass, thereby substantially sealing a fracture within the subterranean formation.   
     
     
         20 . The method of  claim 19 , wherein the lost circulation material composition seals fractures having a size of at least 200 microns. 
     
     
         21 . The method of  claim 19 , wherein the lost circulation material composition seals fractures having a size of from 200 microns to 4000 microns. 
     
     
         22 . The method of  claim 19 , wherein the lost circulation material composition seals fractures having a size of from 500 microns to 2500 microns. 
     
     
         23 . The method of  claim 19 , wherein the lost circulation material composition seals fractures when it is subjected to a temperature of from 70° F. to 400° F. 
     
     
         24 . The method of  claim 19 , wherein the lost circulation material composition seals fractures when it is subjected to a temperature of from 150° F. to 250° F. 
     
     
         25 . The method of  claim 19 , wherein the lost circulation material composition comprises:
 45 to 60 weight percent of diatomaceous earth;   5 to 15 weight percent of graphitic material;   5 to 15 weight percent of ground nut shells;   5 to 15 weight percent of ground fibrous cellulosic material;   5 to 15 weight percent of synthetic chopped fibers;   10 to 20 weight percent of calcium sulfate hemihydrate; and   2 to 12 weight percent of sodium metasilicate.   
     
     
         26 . The method of  claim 19 , wherein the carrier fluid is selected from the group consisting of water, base oil, water based drilling fluid and non-aqueous based drilling fluid. 
     
     
         27 . The method of  claim 19 , wherein the lost circulation material is added to the carrier fluid in an amount of up to about 70 pounds per barrel. 
     
     
         28 . The method of  claim 19 , wherein the lost circulation material forms an unweighted filter cake having a shear strength of up to about 1325 psi at room temperature. 
     
     
         29 . The method of  claim 19 , wherein the lost circulation material forms an unweighted filter cake having a shear strength per dtex of the synthetic chopped fibers of up to about 1366 psi/dtex at room temperature. 
     
     
         30 . The method of  claim 19 , wherein a weighting material is added to the mixture of the lost circulation material composition and the carrier fluid, the weighting material being selected from the group consisting of barite, salt and calcium carbonate. 
     
     
         31 . The method of  claim 30 , wherein the lost circulation material forms a 12.0 lb/gal filter cake having a shear strength of up to about 420 psi at room temperature. 
     
     
         32 . The method of  claim 30 , wherein the lost circulation material forms a 12.0 lb/gal filter cake having a shear strength per dtex of the synthetic chopped fibers of up to about 432 psi/dtex at room temperature. 
     
     
         33 . A system for drilling a subterranean wellbore, comprising:
 a drill string including a drill bit; and   a lost circulation material composition, wherein the lost circulation material composition, comprises:
 particulate material; 
 fibrous material comprising synthetic chopped fibers selected from the group consisting of polyacrylonitrile fibers and acrylonitrile/methyl acrylate fibers; and 
 non-Portland cement material; 
   wherein the lost circulation material is placed in the subterranean formation through the drill string.

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