Coal seams typically to have a significant resistivity contrast to the surrounding rocks and, as such, lend itself to the CSEM technology. Rocksource’s integrated approach to CSEM technology and reservoir modelling may be particularly beneficial for the coal industry, as the EM data allows for identification and delineation of coal seams. Furthermore, reservoir modelling allows for building detailed models of coal distribution based on sedimentological, petrophysical and sequence stratigraphic knowledge. The combination of the two methods should thus allow for detailed understanding of coal distribution in the subsurface. This should be valuable both for exploration and production purposes.
EM data looses detail with depth due to the attenuation of the electromagnetic field in the subsurface and provides a challenge for subsurface exploration of hydrocarbons. However, the coal mining industry is concerned with coal seams buried less than a few hundred metres depth. This allows for the use of higher frequency EM data and thus higher resolution of the subsurface resistivity distribution. In addition, it may prove beneficial to locate EM sources and receivers, not only on the surface, but also within existing coal mines. It may well be that the use of CSEM data has a more optimal potential in the coal industry than in the oil and gas industry, although research and testing is needed to verify this. Furthermore, methane accumulations are commonly associated with coal seams (coal bedded methane) and proper mapping of coal seams, also at greater depths than that considered commercial for coal mining, may have significant implications for the coal bed methane industry, both onshore and offshore. The needed knowledge to make use of an integrated approach (CSEM data and reservoir modelling) in the coal industry sits within Rocksource and future technology development within the company will have significant cross-over potential to the mining industry. Future work to bring the EM technology from exploration into production will further strengthen this potential.