Characterization of shales using T1–T2 NMR maps

• T1–T2 NMR maps are used to identify all proton populations present in a shale sample.
• In 2D T1–T2 maps, the signatures of water, methane and kerogen do not overlap.
• The connectivity of the pore network is determined from a NMR tracer technique.
• In shales, the NMR T2 distribution is not representative of the pore size distribution.

Nuclear Magnetic Resonance (NMR) relaxation methods are key techniques for evaluating shales, from both cores and logging data. First, very small pore sizes, down to nano-meter length scales, can be detected and quantified if the NMR tool has the ability to measure relaxation times in the range [0.1–1 ms], and second the different proton populations (water, oil, gas, and kerogen) can be distinguished using 2D T1–T2 maps. We use a NMR instrument working at a higher frequency (23 MHz) that yields a much higher sensitivity than standard plug-size benchtop apparatus. In this work, we show the position of each proton population in this map: hydroxyls from the clay (T2<0.1 ms, 10

Figure optionsDownload as PowerPoint slide