Fuel, Vol.153, 231-239, 2015
A new rapid method for shale oil and shale gas assessment
Unconventional hydrocarbons represent the future of fossil fuel supply. Arguably the most exciting unconventional deposits are those provided by shale gas and shale oil, hydrocarbons generated and retained by fine grained sedimentary rocks. Effective exploration for shale gas and shale oil requires screening of large numbers of samples in a time and cost effective manner. The most promising samples are then selected for more sophisticated and time consuming procedures. We have examined a new screening technique for shale gas and shale oil. Pyrolysis-FTIR provides a substantial amount of information related to shale quality in a single analysis including the types of gases present (including methane) and the nature of any liquid hydrocarbons released. Construction of calibration curves allows the rapid determination of gas quantities and the average chain length of aliphatic hydrocarbons present. Application of pyrolysis-FTIR to Carboniferous oil shales from the Midland Valley of Scotland reveal percentage levels of methane. Following pyrolysis at 600 degrees C, immature Type III kerogen containing shale has relative gas abundances in the order water > carbon dioxide > methane, mature Type I kerogen containing shales have gas abundances that follow the order water > methane > carbon dioxide and post mature Type I kerogen containing shales have relative abundances in the order carbon dioxide > water > methane. Multistep pyrolysis-FTIR reveals carbon speciation and the relative responses at low and high temperatures reflect sample maturity. The new pyrolysis-FTIR technique can provide a relatively simple and labour saving, but information-rich, technique for the assessment of shale oil and shale gas targets. (C) 2015 The Authors. Published by Elsevier Ltd.