Comments on 'Construction of synthetic capillary pressure curves from the joint use of NMR log data and conventional well logs'

摘要

Recently, Eslami el al., (2013) proposed a method of constructing pseudo capillary pressure curves by combining with NMR log data and conventional well logs following a two-step approach. Using this method, Eslami et al. declared that the simulated P-c curves showed a good agreement with laboratory derived mercury injection capillary pressure (MICP) curves at low mercury saturations (<35%). However, detailed comparison of the constructed pseudo P-c curves with the experimented results illustrates that the constructed P-c curves are overestimated. The parts for constructed P-c curves with mercury injection saturations (S(Hg)s) higher than 35% are all under the laboratory experimented results. This means this technique cannot be accurately apply for formation pore structure evaluation, especially for carbonate rocks and tight sandstone reservoirs. In this paper, we point out that the uncertainty Eslami's method is caused by the dimension difference of mercury injection pressure and 8 T-2 porosity bins, and a technique of improving P-c curve construction is proposed. The reliability of the improved technique is verified by the application of the same 3 core samples displayed in Eslami's paper. (C) 2015 Elsevier B.V. All rights reserved.