A mobile NMR device for measurements of porosity and pore size distributions of drilled core samples

A new mobile NMR scanner has been designed with a Halbach magnet for measurements of porosity and pore-size distributions of water-saturated cylindrical geological cores with diameters up to 60 mm. It is light (∼8 kg) and has a sufficiently homogeneous magnetic field in a large and accessible cylindrical volume. Practical aspects of the sensor construction are described. First experimental results obtained with the mobile Halbach sensor are reported in an attempt to measure porosity and pore-size distributions in geological drilled cores. Compared to the NMR-MOUSE®, the Halbach tool is more sensitive, and porosities can be determined down to 3%. The scanner is a laboratory prototype of a future tool for measuring porosity and pore-size distributions of standard-size cores drilled from the ocean floor. The tool is particularly attractive for use on research vessels and on logging platforms. © 2004 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 23B: 26–32, 2004.