Methods for determining organic matter in shale

Abstract

A method for analyzing a subterranean formation including measuring an electromagnetic spectrum of a rock sample of the subterranean formation using optical spectroscopy, identifying a first kerogen pixel of a plurality of pixels of the electromagnetic spectrum, and analyzing the first kerogen pixel and estimating a property of the first kerogen pixel.

What is claimed: 
     
         1 . A method for analyzing a subterranean formation comprising:
 measuring an electromagnetic spectrum of a rock sample of the subterranean formation using optical spectroscopy;   identifying a first kerogen pixel of a plurality of pixels of the electromagnetic spectrum; and   analyzing the first kerogen pixel and estimating a property of the first kerogen pixel.   
     
     
         2 . The method of  claim 1 , wherein the rock sample is at least one selected from the group consisting of a core, a cutting, an outcrop, a mined sample, and downhole. 
     
     
         3 . The method of  claim 1 , wherein identifying further comprises:
 measuring a spectral intensity of a first pixel and a second pixel of the plurality of pixels of the electromagnetic spectrum; and   comparing the spectral intensity of the first pixel and the second pixel to determine the first kerogen pixel.   
     
     
         4 . The method of  claim 1 , wherein the electromagnetic spectrum comprises at least one selected from the group consisting of an ultraviolet electromagnetic spectrum, a visible electromagnetic spectrum, and a near-infrared electromagnetic spectrum. 
     
     
         5 . The method of  claim 1 , wherein the electromagnetic spectrum comprises a plurality of wavelengths. 
     
     
         6 . The method of  claim 1 , wherein the property of the first kerogen pixel is at least one selected from the group consisting of kerogen type and kerogen maturity. 
     
     
         7 . The method of  claim 1  further comprising:
 estimating at least one selected from the group consisting of reservoir quality and completion quality of the subterranean formation based on the property of the first kerogen pixel. 
 
     
     
         8 . The method of  claim 1  further comprising:
 identifying a second kerogen pixel; 
 analyzing the second kerogen pixel and estimating a property of the second kerogen pixel; and 
 comparing the first kerogen pixel to the second kerogen pixel to determine a property variation between the first and second kerogen pixels. 
 
     
     
         9 . The method of  claim 8 , wherein comparing further comprises:
 identifying an adjacent pixel that is adjacent the first kerogen pixel and having a composition different than the first kerogen pixel; and   comparing the second kerogen pixel to the first kerogen pixel to determine an effect of the adjacent pixel on the property variation between the first kerogen pixel and the second kerogen pixel.   
     
     
         10 . The method of  claim 8 , wherein comparing further comprises:
 determining a first kerogen type of the first kerogen pixel and a second kerogen type of the second kerogen pixel; and   comparing the first kerogen type to the second kerogen type to determine an effect of kerogen type on the property variation between the first kerogen pixel and the second kerogen pixel.   
     
     
         11 . The method of  claim 8 , wherein the property variation is at least one selected from the group consisting of maturity variation and type variation. 
     
     
         12 . A method for analyzing a subterranean formation comprising:
 measuring a first and a second electromagnetic spectrum of at least one rock sample of the subterranean formation using optical spectroscopy;   analyzing a first pixel of the first electromagnetic spectrum and a second pixel of the second electromagnetic; and   comparing a spectral intensity of the first pixel to the spectral intensity of the second pixel to determine a kerogen pixel.   
     
     
         13 . The method of  claim 12 , wherein the first electromagnetic spectrum is at least one selected from the group consisting of an ultraviolet electromagnetic spectrum, a visible electromagnetic spectrum, and a near-infrared electromagnetic spectrum and the second electromagnetic spectrum is the other of the ultraviolet electromagnetic spectrum, the visible electromagnetic spectrum, and the near-infrared electromagnetic spectrum. 
     
     
         14 . The method of  claim 12 , wherein the kerogen pixel is determined by identifying an increase in absorption of either the first or the second pixel when wavelength decreases. 
     
     
         15 . The method of  claim 12  further comprising:
 analyzing the kerogen pixel and estimating a property of the kerogen, wherein the property of the kerogen is at least one selected from the group consisting of kerogen type and kerogen maturity. 
 
     
     
         16 . The method of  claim 12  further comprising:
 estimating at least one selected from the group consisting of reservoir quality and completion quality of the subterranean formation based on the property of the kerogen. 
 
     
     
         17 . A method for hydraulic fracturing of a subterranean formation comprising:
 measuring a electromagnetic spectrum of a first rock sample of the subterranean formation using optical spectroscopy;   identifying a plurality of kerogen pixels in the electromagnetic spectrum;   analyzing the plurality of kerogen pixels and estimating properties of the plurality of kerogen pixels;   estimating a property of the subterranean formation based on the properties of the plurality of kerogen pixels; and   performing a drilling operation based on the property of the subterranean formation.   
     
     
         18 . The method of  claim 17 , wherein the property of the subterranean formation is at least one selected from the group consisting of reservoir quality and completion quality. 
     
     
         19 . The method of  claim 17 , wherein the properties of the plurality of kerogen pixels is at least one selected from the group consisting kerogen type and kerogen maturity. 
     
     
         20 . The method of  claim 17  further comprising:
 measuring a second electromagnetic spectrum of a second rock sample of the subterranean formation using optical spectroscopy; 
 identifying a second plurality of kerogen pixels in the second electromagnetic spectrum; 
 analyzing the second plurality of kerogen pixels and estimating properties of the second plurality of kerogen pixels; 
 estimating a second property of the subterranean formation based on the properties of the second plurality of kerogen pixels; 
 modifying an operating parameter based on a comparison the second property to the first property of the subterranean formation; and 
 performing a downhole operation based on the modified operating parameter. 
 
     
     
         21 . The method of  claim 20 , wherein the second rock sample occurs at a depth different that the first rock sample. 
     
     
         22 . The method of  claim 20 , wherein the operating parameter is at least one selected from the group consisting of injection rate, injection pressure, fluid viscosity, fluid composition, and fluid density.