Using NMR Spectra to Determine Compositions of Unconsolidated Sand / Clay / Brine / Heavy Oil Samples
Manalo, F.P., Lastockin, D., Bryan, J. and Kantzas, A.
SCA2003-59, presented at the 2003 International Symposium of the Society of Core Analysts, held in Pau, France, September 21-24, 2003.
Low field nuclear magnetic resonance (NMR) is incapable of detecting the complete signal from heavy oil and bitumen because part of the signal relaxes too quickly to be measured. In samples that are free of clays or have high water contents, the contribution from water to the NMR spectrum is distinct from heavy oil and bitumen, thus one can calculate water content and oil content is assumed to be the difference. It is more difficult to determine the oil content in partially saturated samples that also contain clay because the relaxation times of clay bound water and heavy oil and bitumen fall in the same range. Results from samples with clays, sand and low-salinity brine show that clay bound water has a characteristic response. Heavy oil was added and the differences in the NMR spectra before and after heavy oil addition were used to create a preliminary predictive algorithm for determining clay content in clay/brine suspensions and solids/brine/oil systems. This algorithm predicts oil, water and clay content and may lead to improved characterization of ores and froths as well as enhanced oils sands recovery.