A sample acquired during hydrocarbon exploration or production, and comprising at least one of water, hydrocarbons or solids, is sensed by performing continuous wave nuclear magnetic resonance measurements of the amount of a relevant type of nucleus from which a measure of the composition of the sample is derived. During a scan through resonance of the one or more types of nuclei, there is detected an absorption measurement of the absorbed energy of the electromagnetic field, that may be an integrated measure of instantaneous absorption. Hydrogen nuclei may be measured to derive a measure of the amount of water in the sample. Chlorine nuclei and/or sodium nuclei may be measured to derive a measure of the salinity of the sample.