A novel method for quantitative analysis of brine and oil saturation in a sealed low permeable core based on one-dimensional (1D) NMR technique

Abstract

The nondestructive technology for analyzing the in-situ brine and oil distribution is of great significance for laboratory characterization of the sealed core samples. In this paper, a novel method is proposed for quantitative analysis of brine and thin oil saturation in a sealed low permeable core based on one dimensional (1D) NMR technique. Based on the difference of critical phase transition temperature of the two components, the variation of 1H proton spin relaxation signal for oil and water phase could be distinguished and therefore the oil and water saturation could be measured in the nondestructive manner. The proposed method, including the experimental and data analysis procedure was demonstrated and validated in the case on determination of oil/brine composition in a sealed low permeable sandy conglomerate sample. Through comparison of the T2 spectrum at temperature of 25 °C where both brine and oil are in liquid phase and at temperature of −15 °C where the brine freezes to solid phase, the brine and oil saturation in the low permeable core are successfully obtained. It is expected the proposed method could essentially support the laboratory analysis of the in-situ component compositions.