Publication details
Evaluation of the Gas Content in Archived Shale Samples: A Carbon Isotope Study
| Authors | |
|---|---|
| Year of publication | 2019 |
| Type | Article in Periodical |
| Magazine / Source | Arabian Journal of Geosciences |
| MU Faculty or unit | |
| Citation | |
| Web | https://www.mdpi.com/2076-3263/9/11/481 |
| Doi | http://dx.doi.org/10.3390/geosciences9110481 |
| Keywords | shale gases; carbon isotopes; chemical composition; diffusion |
| Description | We examined 14 archived samples of shale for the chemical and C-13 isotopic composition of residual gases produced as part of rock-crushing operations at a hammer mill. Results were compared with data on maturity from Rock-Eval pyrolysis and vitrinite reflectance measurements. The samples originated from three different formations (Mikulov Marls, Ostrava Formation, and Lite Formation) located in the Czech Republic. For comparison, we examined a gas-prone shale sample from the Polish Silurian. We used changes in the chemical and isotopic composition of released gases to evaluate the isotope fractionation during gas loss and retroactively calculated the initial content of gas in the shale samples. The gas content estimates (in L of gas per ton of rock) correspond with the maturity parameters of the shales. Calculated isotope fractionation for the gas release was -3 parts per thousand for both methane and ethane. The archived samples primarily lost methane (up to 90%), with subsequent changes in the content of ethane and higher hydrocarbon levels. |