A Supplementary Method for Assessing the Reliability of Fluids Sampled from Deep Aquifers

In deep aquifers, temperatures of formation fluids recovered during drill-stem tests were usually higher than regular bottom-hole temperatures recorded at the same borehole and interval. Wherever the opposite was observed, the sampled formation fluids were diluted with mud filtrate or cushion water. Temperature measurements are a useful criterion for differentiating between representative and contaminated formation-fluid samples.