I specialise in the metrology of geological materials. I design and construct much of the novel instrumentation used for rock physics metrology at the National Oceanography Centre, Southampton. I recently received the prestigious EAGE Loránd Eötvös award for my work on the measurement of electrical anisotropy in rocks. https://noc.ac.uk/news/discovery-new-rock-property-earns-prize
My current and recent research activity includes:
The NOC Pulse Tube
The NOC has recently installed an acoustic pulse tube to measure the velocity and attenuation of sediment samples over the frequency range of 1-10 kHz. My contribution to this project has been the developed much of the acoustic instrumentation and the digital signal processing algorithms used to measure sediment properties.
The measurement of electrical anisotropy in rocks
To support and advance understanding of resistivity anisotropy at the rock-fabric scale we have developed a system able to measure anisotropic resistivity in single, 50 mm diameter, core samples in the controlled conditions of a laboratory. The measurements are unbiased by sample orientation and the system provides the full 9 component resistivity tensor without assuming a specific anisotropy symmetry. Furthermore, we are able to achieve this under geologically representative conditions of up to 60 MPa effective pressure and controlled temperature while simultaneously measuring elastic wave velocity and attenuation.
Related Conference Papers:
L.J. North, A.I. Best and J. Sothcott . Pressure Sensitivity of the Joint Elastic-electrical Properties of Carbonate Reservoir Rocks. 74th EAGE Conference & Exhibition 2012
L.J. North, A.I. Best and J. Sothcott . Pressure Dependent Electrical Resistivity Anisotropy in Carbonate Reservoir Rocks. 74th EAGE Conference & Exhibition 2012
L.J. North, A.I. Best, J. Sothcott and L. MacGregor. Laboratory Measurements of Electrical Resistivity Heterogeneity and Anisotropy in Carbonate Reservoir Rocks. 73rd EAGE Conference & Exhibition 2011
Investigating the controls on anisotropy in sedimentary rocks using Finite Element Models
A finite element model of an in-silico, balistically deposited grain-pack showing the current paths between faces of the cubic sample. The current paths were found using a fast marching algorithm and help explain the anisotropy observed in the grain pack:
L.J. North, A.I. Best, J. Sothcott and G. Marketos. Compaction Induced Electrical Anisotropy in Sandstones. 75th EAGE Conference & Exhibition incorporating SPE EUROPEC 2013 DOI: 10.3997/2214-4609.20130349
Seafloor greenhouse gas
NERC standard grant, Geophysical quantification of seafloor greenhouse gas: the effect of gas bubble and hydrate morphology on sediment geophysical properties. Measuring the the 1-10KHz acoustic velocity and attenuation and electrical resistivity of gas hydrate bearing sediments.
Turbidity Current Measurement
NERC oil and gas catalyst grant How do turbidity currents interact with man-made structures? A novel Electric Resistivity Tomography approach. Imaging the concentration gradient in turbidity currents using electric impedance tomography.
Carbon Capture And Storage
EPSRC DiSECCS project, Carbon Capture and Storage, monitoring supercritical fluid flow and homogeneity in core sample using electric impedance tomography.
Marine CSEM
DASI, refurbishment of the DASI Controlled Source ElectroMagnetic ultra-low frequency marine radio transmitter.
