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Modelling Permeability in Rotliegend Gas Sandstones from NMR
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 77th EAGE Conference and Exhibition 2015, Jun 2015, Volume 2015, p.1 - 5
Abstract
Permeability characterisation of low permeability, clay-rich gas sandstones is part of production forecasting and reservoir management. We studied 63 samples from North West European Rotliegend sandstone reservoirs, where the pore sizes can range from nm to μm in order to estimate which pores control permeability to gas. Petrography indicates that large pores are connected by narrow flow paths, so we used nuclear magnetic resonance (NMR) transverse relaxation data to estimate pore size distribution, and then modelled gas permeability by summing the contributions for each pore size increment from the small pore-side, thus leaving out the contribution from the largest pores. Apparent pore size distribution from mercury injection data relate poorly to NMR data, but the results can be consistently interpreted from petrographic analysis and clay mineralogy.