Method and apparatus for fracing earth formations surrounding a wellbore

Abstract

A dry powder product comprised of an inorganic silicate-based compound and an organic compound are mixed with fresh water as a catalyst, such that the mixture enters into hydration reaction, and when injected into existing fractures in low permeability formations surrounding earth boreholes, the resulting increase in volume of the mixture from the hydration reaction causes the existing fractures to have increased dimensions. Because the hydrationreactionbetweenwater and the drypowderwill commence almost as soon as the water is mixed with the dry powder, there are various means and methods described to inhibit the hydration reaction from occurring until after predetermined times, for example, such as by using water soluble coatings for encapsulating the dry powder which dissolve after predetermined times, and by using water insoluble coatings over the powder and by causing the capsules to be mechanically disintegrated to allow water to come into contact with the dry powder, and by providing means for transporting the dry powder from the earth's surface in the tubular string down to the formation of interest surrounding the wellbore, the hydration reaction can be inhibited for predetermined periods of time.

1 . A fluid for the further fracturing of a low permeability formation surrounding an earth borehole, comprising: 
 a first silicate-based inorganic compound;    a second organic compound; and    water, said first and second compounds and said water, when mixedig the ability to enter into hydration reaction and to thereafter expand the volume of said mixture within an existing fracture in said formation to thereby increase the dimensions of said existing fracture.    
     
     
         2 . The fluid according to  claim 1 , wherein the first compound and the second compound comprise a dry powder encapsulated with a water soluble shell prior to being mixed with the water.  
     
     
         3 . The fluid according to  claim 1 , wherein the first compound and the second compound comprise a dry powder encapsulated with a water insoluble shell prior to being mixed with the water.  
     
     
         4 . A process for the further fracturing of a low permeability formation surrounding an earth borehole comprising: 
 Mixing a dry powder comprised of a first silicate-based inorganic compound and a second organic compound with water to create a frac fluid at the earth's surface;    Pumping said frac fluid from the earth's surface down to said formation to be further fractured, and into existing fractures in said formation to thereby expand the volume of said frac fluid in said existing fractures by hydration reaction, thereby increasing the dimensions of said existing fractures.    
     
     
         5 . The process according to  claim 4 , wherein said dry powder is encapsulated with a water soluble fluid.  
     
     
         6 . The process according to  claim 4 , wherein said dry powder is encapsulated with a water insoluble shell.  
     
     
         7 . The process according to  claim 6 , wherein said encapsulated dry powder is mechanically disintegrated prior to mixing with water.  
     
     
         8 . The process according to  claim 4 , wherein said water is chilled at the earth's surface.  
     
     
         9 . The process according to  claim 4 , wherein said dry powder is transported in its dry condition from the earth's surface to the proximity of the formation to be further fractured.