By Mohammad Monzurul Alam
“Interpretation of low field NMR data for minerals in brine”
Abstract
Low salinity waterflooding in sandstone reservoirs has proven a successful method for Enhanced Oil Recovery (EOR), whereas, in carbonate rocks specific ions show interaction on the calcite surface. It indicates that optimized salt water waterflooding could also be possible in carbonate reservoirs for EOR. Both sandstone and carbonates contains a fraction of clay in them. Clay content in these rocks could have significant influence on low salinity or optimized salt water waterflooding. We studied the interaction of Mg2+, Ca2+, Na+ and SO42+ ions on pure quartz, calcite and kaolinite surfaces by using the nuclear magnetic resonance (NMR) method. The transverse relaxation time of NMR is affected by the distribution of water molecules close to the solid surface. This behaviour is characterized by surface relaxivity (ρ). We observed that the surface relaxivity for kaolinite and calcite is affected by the presence of specific ions, whereas for kaolinite and quartz it is affected by salinity.