Gas Sorption Analysis Of Unconventional Rock Samples

Abstract

Systems and methods for gas sorption analysis, or analogous practices, of samples from unconventional reservoirs are described. The described analysis of samples is used to determine various properties of unconventional reservoirs, which are used in evaluating their worth and producibility.

What is claimed is: 
     
         1 . A method of analyzing rock samples from an unconventional hydrocarbon reservoir comprising:
 grinding and sieving a sample of rock from the unconventional hydrocarbon reservoir;   degassing the sample of rock;   performing gas sorption on the sample of rock; and   determining at least one characteristic associated with the sample based at least in part on the gas sorption.   
     
     
         2 . The method of  claim 1 , wherein the sample is at least one of a core sample or a cutting sample from the unconventional hydrocarbon reservoir. 
     
     
         3 . The method of  claim 1 , wherein the at least one characteristic includes a measurement of one or more types selected from a group consisting of: total organic content, surface area, thermal maturity, pore size distribution, pore volume, volume of micropores, free gas capacity, permeability, fractal dimension, and correlation length. 
     
     
         4 . The method of  claim 1 , wherein the sample includes a plurality of particles. 
     
     
         5 . The method of  claim 4 , wherein a size of the plurality of particles is selected from a range of sizes. 
     
     
         6 . The method of  claim 1 , further comprising:
 calculating a bulk density, a skeletal density, a pore volume, a surface area or a pore size distribution of the sample using mercury intrusion porosimetry.   
     
     
         7 . The method of  claim 1 , further comprising:
 calculating a skeletal density of the sample;   calculating a bulk density of the sample; and   determining a pore volume of the sample from the calculated skeletal density and the bulk density.   
     
     
         8 . The method of  claim 7 , further comprising:
 using pycnometry to calculate the skeletal density.   
     
     
         9 . The method of  claim 1 , further comprising:
 extracting bitumen from the sample using a solvent;   extracting kerogen from the sample using combustion; and   calculating a pore volume, surface area and pore size distribution of the sample.   
     
     
         10 . The method of  claim 3 , wherein the at least one characteristic is used to determine a location for initiating a fracture in the unconventional hydrocarbon reservoir. 
     
     
         11 . The method of  claim 1 , wherein the unconventional hydrocarbon reservoir includes hydrocarbon-bearing shales. 
     
     
         12 . The method of  claim 3 , wherein a size of the micropores is smaller than 2 nm 
     
     
         13 . The method of  claim 1 , wherein performing gas sorption on the sample uses one of nitrogen, water, carbon dioxide, argon, xenon, neon, or combinations thereof. 
     
     
         14 . The method of  claim 1 , further comprising:
 extracting the sample from an unconventional hydrocarbon reservoir at a plurality of depths in the reservoir.