Application Benefits of Using Downhole Magnetic Resonance and Wireline Geophysical Logging for Geotechnical Ground Investigation Projects

Geotechnical ground investigations in nearshore conditions requires a level of precision and accuracy in the determination of subsurface parameters that is more rigorous than most applications of geophysical logs. As such, these projects demand a wealth of measurements of the subsurface by geophysical means. In the following examples for detailed interpretation of wireline logging, geotechnical data and packer test results are presented with particular interest to benefits of the DMR method and the detailed log analysis the geotechnical industry. Expansive suite of wireline logs included DMR, optical and acoustic televiewer, orientated four arm caliper, gamma-gamma density, resistivity and acoustic methods, leading to an accurate understanding of the rock strength and geo-mechanical properties. DMR measurements provided continuous total porosity and pore-size distribution data. Permeability estimations were also performed using DMR Porosity and T2 distribution data, packer test derived, in-situ permeability results were used to refine estimated permeabilities. Ability to significantly lower construction related risk by facilitating identification and detailed description of weak zones justifies the use of wireline geophysical logging and particularly the DMR method more broadly in the construction and engineering sectors.