PROCESS FOR HYDRAULIC FRACTURING WITH pH CONTROL

Abstract

A process for hydraulic fracturing including the steps of (a) providing a fracturing fluid by combining water, proppant, an oxidizing biocide, and a friction reducer; (b) introducing the fracturing fluid into a well; and (c) controlling the pH of the fracturing fluid to a pH of at least about 4.5.

What is claimed is: 
     
         1 . A process for hydraulic fracturing comprising
 (a) providing a fracturing fluid by combining water, proppant, an oxidizing biocide, and a friction reducer;   (b) introducing the fracturing fluid into a well; and   (c) controlling the pH of the fracturing fluid to a pH of at least about 4.5.   
     
     
         2 . The process of  claim 1  wherein the pH is controlled by (i) measuring the pH of (1) at least one of the water, oxidizing biocide, or friction reducer, prior to combining step (a) or (2) the fracturing fluid, prior to or after the fracturing fluid is introduced into a well in step (b); (ii) comparing the measured pH with a set point of a desired pH; (iii) calculating the difference between the desired pH and the measured pH ; and (iv) generating a signal which corresponds to the difference calculated in (iii) which provides a feedback response to a controller for adding a base to the at least one of the water, biocide or friction reducer or the fracturing fluid to control the pH of the fracturing fluid at a pH of at least about 4.5. 
     
     
         3 . The process of  claim 3  wherein any one or all of the steps (i) through (iv) is performed manually. 
     
     
         4 . The process of  claim 3  wherein the base is ammonium hydroxide, an alkali metal salt or alkaline earth metal salt of hydroxide, oxide, bicarbonate, carbonate, or combinations of two or more thereof. 
     
     
         5 . The process of  claim 1  wherein the oxidizing biocide is selected from the group consisting of bleach, peroxides, peracids, persulfates, ozone, chlorine dioxide, and combinations thereof. 
     
     
         6 . The process of  claim 1  wherein the friction reducer is an anionic polyacrylamide or polyacrylamide co-polymer. 
     
     
         7 . The process of  claim 1  wherein the pH is at least about 5.5. 
     
     
         8 . The process of  claim 1  wherein the pH is less than about pH 7. 
     
     
         9 . The process of  claim 2  wherein the pH of the fracturing fluid is measured and is measured prior to introducing the fracturing fluid into the well. 
     
     
         10 . The process of  claim 2  wherein at least a portion of the water is produced water.