Geology & Geophysics Group
Exploration geophysics
Contact: Prof. Martin Sinha
Seismic and electromagnetic geophysical survey methods are widely used to study geological structures and physical properties beneath continental margins, in regions of potential economic or industrial interest. The Geology and Geophysics Group carries out research into improving methodologies (e.g. instrumentation, survey design, data analysis, modelling, geophysical inversion) for these purposes. Our particular areas of specialism are controlled-source electromagnetic (CSEM) and long-offset seismic methods. For the latter, we also carry out survey work, data analysis and interpretation using specialist non-standard methods, in partnership with industry.
We are world leaders in controlled-source electromagnetic methods, which use a deep-towed low-frequency EM transmitter and arrays of autonomous ocean-bottom receivers to create cross-sections or 3-dimensional maps of electrical resistivity in the sub-surface. Current research focuses on improved methods for CSEM imaging, and applications of CSEM technology to appraisal and monitoring of hydocarbon reservoirs. We work closely in partnership with Offshore Hydrocarbon Mapping plc (OHM), whose origins in 2002 were as a University of Southampton spin-out company. OHM provides the full range of commercial EM survey, design, acquisition, analysis and interpretation services to industry clients.
Above right: NOC’s DASI-2 deep-towed electromagnetic transmitter system assembled ready for use on the deck of RRS Charles Darwin, during an industry partnership project.
Long offset seismic techniques are of increasing interest in hydrocarbon exploration; both as an exploration tool in regions where conventional reflection seismics perform poorly (for example under salt), and to determine deep basin structure in frontier hydrocarbon regions. Understanding the crustal type and thickness is vital to reducing exploration risk in deep water areas. We have extensive experience of working with the hydrocarbon industry in the acquisition and interpretation of long offset seismic data, for both 2D and 3D datasets.
Above left: Control centre in the main laboratory of RRS Charles Darwin during DASI-2 controlled-source electromagnetic survey operations.
Above: Fence diagram showing the crustal structure in the Eastern Black Sea Basin, from tomographic modelling of wide-angle seismic data acquired using Ocean Bottom Seismographs (OBS) and a large airgun source.
Our research in exploration geophysics has close links to our work in physical properties and effective medium theories; in high-resolution 3-D seismic imaging of shallow sedimentary structures in deep water; and in deep water sediment transport and deposition processes. The latter two correspond in many cases to studies of modern analogues for the creation in the past of formations that now act as deep water reservoir rocks.
Links:
- Seafloor EM research
- Long offset seismics
- Seafloor EM instruments
- OBIC
- 3D seismic instruments
- OHM
- Black Sea project
- Ed Morris (PhD)
- Anna Maxey (PhD)
- LITHOS
