Total Organic Hydrogen Content from Double Quantum Filtered Signal Intensity
Publication Date: 2011-Dec-28
The IP.com Prior Art Database
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Total organic hydrogen content from double quantum filtered signal intensity
Shale plays are an increasingly important part of unconventional resource exploration. Identifying the content, type, and maturity of organic matter in shales is an important indicator to determine what petroleum hydrocarbons may be present, in what quantities, and their ability to be produced through the organic and mineral microstructure. Our data do not indicate any trends in the double quantum filter signal (DQF) signal in relation to maturity or type. However, we have a limited number of samples and potentially more samples may indicate a trend. This invention describes a method to attempt to measure organic matter abundance (via total organic hydrogen, TOH), composition (type I, II, III), speciation (kerogen, bitumen, oil, gas), and maturity (H/C ratio) by rapid and non-destructive lab or well side, of whole rock.
The invention describes a method for measuring total organic hydrogen atoms in shales. Initial measurements indicate a correlation between measured double quantum filter signal and TOC, allowing an estimate of organic content via a rapid, non-destructive lab or well side application. Performing a DQF experiment in addition to a DT2 experiment may allow us to provide organic matter speciation (kerogen, bitumen, oil, gas) and maturity (H/C ratio).
The bulk abundance and composition of organic matter in geologic samples is generally evaluated in the laboratory by pyrolytic or combustion based techniques following laborious removal of the rock mineral matrix by hazardous hydrochloric and hydrofluoric acid digestion. In Rock-Eval pyrolysis, the effluent produced from heating a sample aliquot under an inert atmosphere is monitored in three stages. In the first stage (known as S1), the temperature is kept isothermal at 300°C, releasing the volatile components. The temperature is then ramped to 550°C in the second stage (S2), resulting in the thermal cracking of the non-volatile organic matter. The evolved matter from these first two stages is quantified with a flame ionization detector (FID). In the third stage (S3), the amount of CO2 produced from 300-390°C is measured using a thermal conductivity detector (TCD). In this way, the sum of S1+S2+S3 peaks can be used as a crude metric of total organic carbon (TOC) content, whereas the amounts of hydrogen and oxygen can be approximated using the S2/(S1+S2+S3) and S3/(S1+S2+S3) ratios, respectively. A more accurate measurement of hydrocarbon content and type can be derived from combustion elemental analysis (EA). This technique involves a tin-catalyzed high temperature combustion of a sample aliquot, subsequent chromatographic separation of the resulting CO2, N2, H2O, and SO2 species, and TCD quantification to yield the organic carbon, nitrogen, hydrogen, and sulfur content. The oxygen content is similarly obtained under anoxic reactor condi...