摘要
Aiming at obtaining an accurate porosity of gas shale,various approaches are attempted.Therein,nuclear magnetic resonance(NMR),being treated as a kind of new-developed technique,possesses the representative significance.However,as a booming technique,the reliability of NMR-based porosity of shale is not exactly defined.Depending on NMR device,this work measured the porosity of shale experiencing different water soaking time,accordingly,judging the reliability of NMR-based porosity.Results indicate the NMR outcomes vary with the water soaking time,making a doubt about the objectivity of NMRbased porosity in reflecting the real shale porosity.Furthermore,some supplementary means were adopted to verify the water soaking-induced variation in the pore system of shale sample,which intensities the suspicion if the NMR-based porosity is reliable or not.To sum up,this work considers that the NMR-based porosity of shale is not reliable enough when water is used as the probe.Besides,this work also offers some suggestions on how to enhance the reliability of NMR-based porosity of shale sample.Basically,this work selects a fresh perspective to analyze the NMR approach in determining shale porosity,which is hopefully helpful in promoting the development of NMR technique in the shale-related field.
基金
financially supported by the Science and Technology Department of Sichuan Province(Grant Nos.2021YFH0048 and 2021YFH0118)
the Project funded by China Postdoctoral Science Foundation(Grant No.2020M683253)
