Methods to enhance silica sand proppant for use in fracking operations

Abstract

Methods for cost effectively transforming lower quality silica sands into higher quality silica sands for use as proppants in fracking operations involving subterranean hydrocarbon formations. A process of exposing silica sand proppants to locally-sourced electromagnetic radiation, and systems therefor, are disclosed and shown to increase the performance of those silica sands as proppants in hydrocarbon formation fracturing operations.

What is claimed is: 
     
         1 . A method of increasing crush resistance of silica sand proppant used in fracturing operations, the method comprising:
 exposing at least a portion of silica sand proppant to high-frequency electromagnetic radiation from a local electromagnetic radiation source positioned in close proximity to the silica sand proppant to impart heat to the silica sand proppant;   adding the exposed silica sand proppant to a tumbler; and   within a selected period of time after the at least a portion of the silica sand proppant has been exposed to the electromagnetic radiation, tumbling the at least a portion of exposed silica sand proppant in the tumbler.   
     
     
         2 . The method of  claim 1 , further comprising:
 supplying the exposed silica sand proppant, after tumbling, to a well fracturing site for use in the fracturing operations involving one or more subterranean hydrocarbon formations.   
     
     
         3 . The method of  claim 1 , wherein tumbling the at least a portion of the exposed silica sand proppant in the tumbler within the selected period of time occurs within a minute or less after that portion was exposed to the high-frequency electromagnetic radiation. 
     
     
         4 . The method of  claim 1 , wherein the tumbling occurs for at least about five minutes. 
     
     
         5 . The method of  claim 1 , further comprising:
 contacting the silica sand proppant to an acidic solution prior to exposure to the high-frequency electromagnetic radiation.   
     
     
         6 . The method of  claim 5 , wherein the acidic solution also contains an organic removal agent. 
     
     
         7 . The method of  claim 1 , further comprising:
 contacting the silica sand proppant to an ammonium chloride solution in a washer prior to exposing to the high-frequency electromagnetic radiation to provide washed silica sand proppant prior to the step of exposing to the high-frequency electromagnetic radiation.   
     
     
         8 . The method of  claim 7 , wherein exposing the at least a portion of the washed silica sand proppant to the high-frequency electromagnetic radiation further comprises:
 placing the at least a portion of the washed silica sand proppant on a conveyor; and   operating the conveyor to pass the at least a portion of the washed silica sand proppant thereon through a heating chamber into which the local electromagnetic radiation source emits the electromagnetic radiation.   
     
     
         9 . The method of  claim 1 , wherein the high-frequency electromagnetic radiation generated by the local electromagnetic radiation source has a frequency between about 1200 MHz and about 2700 MHz. 
     
     
         10 . The method of  claim 7 , wherein the at least a portion of the washed silica sand proppant is exposed to the electromagnetic radiation for no more than about three minutes. 
     
     
         11 . The method of  claim 7 , wherein the silica sand proppant washed in the washer has been sorted to have a preselected particle size range prior to washing. 
     
     
         12 . The method of  claim 1 , further comprising:
 contacting the silica sand proppant to an organic removal agent prior to exposing to the high-frequency electromagnetic radiation.   
     
     
         13 . The method of  claim 12 , wherein exposing the at least a portion of the silica sand proppant to the electromagnetic radiation further comprises:
 placing the at least a portion of the silica sand proppant on a conveyor; and   operating the conveyor to pass the at least a portion of the silica sand proppant thereon through a first suppression tunnel, a heating chamber and then a second suppression tunnel, the high-frequency electromagnetic radiation emitted by the local electromagnetic radiation source into the heating chamber, the first and second suppression tunnels positioned to reduce electromagnetic radiation leakage from the heating chamber.   
     
     
         14 . The method of  claim 13 , wherein the electromagnetic radiation generated by the local electromagnetic radiation source has a frequency between about 1200 MHz and about 2700 MHz. 
     
     
         15 . The method of  claim 1 , wherein the silica sand proppant has a particle size range of about 20/40 mesh.