oa Magnetic Resonance Soundings and NMR Logging of a Limestone Aquifer- the Tamala Limestone, Western Australia.

Magnetic Resonance Sounding (MRS or Surface Nuclear Magnetic Resonance (SNMR)) is a geophysical technique used for direct groundwater detection and aquifer characterisation. the technique is based upon the nuclear magnetic resonance (NMR) method, most well known in medical imaging. the technique was developed in the early 1980’s but commercial systems only became available in the late 1990’s. the technique has been trialled in Australia previously, but the method has not been fully adopted into common use. the main impediment of the technique is in detecting a very small signal typically 8-10 orders of magnitude less than the background electromagnetic noise. with the advent of new system designs and modern processing technologies the latest developments in MRS have greatly improved the success of the technique. CSIRO is undertaking a study to test the latest in MRS instrument design- the Vista Clara GMR system in Australian settings. As part of the study a trial site over the Tamala Limestone in Western Australia was undertaken as part of a larger hydrogeological study of this particular limestone which provides a groundwater resource to the Perth area, Western Australia.<br>in this project MRS soundings were collected at 3 sites. Following the surface measurements, sonic drilling was performed, and each hole was logged with an NMR tool. in addition laboratory NMR and permeability tests were performed on recovered samples. This paper discusses the results of the three scales of measurements and demonstrates how MRS provides a non invasive method for characterising aquifers.