US2017233642A1PendingUtilityA1

Well Treatment Fluids and Methods

57
Assignee: BAKER HUGHES INCPriority: Aug 7, 2013Filed: May 1, 2017Published: Aug 17, 2017
Est. expiryAug 7, 2033(~7.1 yrs left)· nominal 20-yr term from priority
Inventors:Jia ZhouMagnus LegemahHong SunBrian B. BeallQi Qu
C09K 8/685E21B 43/267C09K 8/90C09K 8/665C09K 8/887E21B 43/26
57
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Claims

Abstract

A well treatment fluid includes an aqueous-based fluid, a crosslinked CMHEC polymer, and a crosslinker. The CMHEC polymer exhibits a DS of 0.2 to 0.6 and a MS of 2.0 to 2.5. The well treatment fluid exhibits a viscosity of at least about 100 cP. A well treatment method includes crosslinking a CMHEC polymer in an aqueous-based fluid at a pH of at least about 6. The crosslinking increases a viscosity of the well treatment fluid to at least about 100 cP. A well is treated with the well treatment fluid at a temperature of at least about 200° F. Another well treatment method includes forming a well treatment fluid from produced water that has a TDS content of at least about 150,000 ppm. The crosslinking increases a viscosity of the well treatment fluid to at least about 100 cP.

Claims

exact text as granted — not AI-modified
What is claimed is: 
     
         1 . A well treatment fluid comprising:
 an aqueous-based fluid containing produced water, the well treatment fluid having a total dissolved solids (TDS) content of at least about 100,000 ppm;   a crosslinked carboxymethyl hydroxyethyl cellulose (CMHEC) polymer exhibiting a degree of substitution (DS) of 0.3 to 0.5 and a molar substitution (MS) of 2.0 to 2.5; and   a crosslinker configured to crosslink the CMHEC polymer in the aqueous-based fluid, the well treatment fluid exhibiting a property of stabilizing a sustained viscosity of greater than or equal to about 100 cP at a sheer rate of 100 sec −1  for a time of at least about 1 hour when at a temperature of at least about 200° F.   
     
     
         2 . The fluid of  claim 1  wherein the well treatment fluid has a TDS content of at least about 150,000 ppm. 
     
     
         3 . The fluid of  claim 1  wherein the well treatment fluid has a divalent cation content as CaCO 3  of at least about 10,000 ppm. 
     
     
         4 . The fluid of  claim 1  wherein the well treatment fluid exhibits a property of stabilizing the sustained viscosity of greater than or equal to about 100 cP at a sheer rate of 100 sec −1  for a time of at least about 2 hours when at the temperature of at least about 200° F. 
     
     
         5 . The fluid of  claim 1  wherein the well treatment fluid exhibits a pH of at least about 6. 
     
     
         6 . The fluid of  claim 1  further comprising Mg(OH) 2 . 
     
     
         7 . The fluid of  claim 1  wherein the well treatment fluid exhibits a property of stabilizing the sustained viscosity of greater than or equal to about 100 cP at a shear rate of 100 sec −1  for a time of at least about 2 hours when at a temperature of at least about 275° F. 
     
     
         8 . The fluid of  claim 1  wherein the well treatment fluid exhibits a property of stabilizing the sustained viscosity of greater than or equal to about 100 cP at a shear rate of 100 sec −1  for a time of at least about 1 hour when at a temperature of at least about 300° F. 
     
     
         9 . The fluid of  claim 5  wherein the pH is from greater than 7 to about 11. 
     
     
         10 . The fluid of  claim 1  wherein the temperature is at least about 250° F. 
     
     
         11 . The fluid of  claim 1  wherein the well treatment fluid has a divalent cation content as CaCO 3  of at least about 25,000 ppm. 
     
     
         12 . A well treatment fluid comprising:
 an aqueous-based fluid formed from produced water, the well treatment fluid having a total dissolved solids (TDS) content of at least about 150,000 ppm and a divalent cation content as CaCO 3  of at least about 10,000 ppm and exhibiting a pH of at least about 6;   a crosslinked carboxymethyl hydroxyethyl cellulose (CMHEC) polymer exhibiting a degree of substitution (DS) of 0.3 to 0.5 and a molar substitution (MS) of 2.0 to 2.5; and   a crosslinker configured to crosslink the CMHEC polymer in the aqueous-based fluid, the well treatment fluid exhibiting a property of stabilizing a sustained viscosity of greater than or equal to about 100 cP at a sheer rate of 100 sec −1  for a time of at least about 1 hour when at a temperature of at least about 200° F.   
     
     
         13 . The fluid of  claim 12  further comprising Mg(OH) 2 . 
     
     
         14 . The fluid of  claim 12  wherein the temperature is at least about 250° F. and the divalent cation content as CaCO 3  is at least about 25,000 ppm. 
     
     
         15 . The fluid of  claim 12  wherein the well treatment fluid exhibits a property of stabilizing the sustained viscosity of greater than or equal to about 100 cP at a shear rate of 100 sec −1  for a time of at least about 2 hours when at a temperature of at least about 275° F. 
     
     
         16 . The fluid of  claim 12  wherein the well treatment fluid exhibits a property of stabilizing the sustained viscosity of greater than or equal to about 100 cP at a shear rate of 100 sec −1  for a time of at least about 1 hour when at a temperature of at least about 300° F. 
     
     
         17 . A well treatment fluid comprising:
 an aqueous-based fluid formed from produced water, the well treatment fluid having a total dissolved solids (TDS) content of at least about 150,000 ppm and a divalent cation content as CaCO 3  of at least about 10,000 ppm;   Mg(OH) 2 , the well treatment fluid exhibiting a pH from greater than 7 to about 11;   a crosslinked carboxymethyl hydroxyethyl cellulose (CMHEC) polymer exhibiting a degree of substitution (DS) of 0.3 to 0.5 and a molar substitution (MS) of 2.0 to 2.5; and   a crosslinker configured to crosslink the CMHEC polymer in the aqueous-based fluid, the well treatment fluid exhibiting a property of stabilizing a sustained viscosity of greater than or equal to about 100 cP at a sheer rate of 100 sec −1  for a time of at least about 1 hour when at a temperature of at least about 200° F.   
     
     
         18 . The fluid of  claim 17  wherein the temperature is at least about 250° F. and the divalent cation content as CaCO 3  is at least about 25,000 ppm. 
     
     
         19 . The fluid of  claim 17  wherein the well treatment fluid exhibits a property of stabilizing the sustained viscosity of greater than or equal to about 100 cP at a shear rate of 100 sec −1  for a time of at least about 2 hours when at a temperature of at least about 275° F. 
     
     
         20 . The fluid of  claim 17  wherein the well treatment fluid exhibits a property of stabilizing the sustained viscosity of greater than or equal to about 100 cP at a shear rate of 100 sec −1  for a time of at least about 1 hour when at a temperature of at least about 300° F.

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