The irreducible water content has been evaluated using nuclear magnetic resonance (NMR) method. Estimation of the irreducible water content in the pore space is indispensable for the productive porosity evaluation and characteristics of the reservoir properties of rocks. The irreducible water content has been established calculating the cutoff time T2G (parameter which enables the division between irreducible and free water). Different types of sandstones were investigated. Variability of the estimated Tlcj values (3-15 ms) is connected with the diversity of the pore space structure and mineralogy of the investigated rocks. The average T2a value (9.14 ms) established experimentally differs considerably from the average value presented in the literature (33 ms). Use of an average T2a = 33 ms value in the interpretation of the NMR measurements may result in great, even 100 percent errors in the estimation of the producible porosity. Thus, it is clear that investigations of real T2 values for rocks from different sedimentary basins is necessary.
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