Geophysical Methods for Subsurface Characterisation

The course has three parts:

• reflection seismology

• electrical sounding

• borehole logging,

and combines these parts in an integrated manner.

The reflection-seismology part deals with the most important aspects of reflection seismology: theory of seismic waves and aspects of data acquisition and data processing (CMP processing, velocity analysis, stacking, and migration) are dealt with. The reflection-seismology part are supplemented by a practical of 4 afternoons, where the students will see the most important data-processing steps via exercises (in Python).

The electric-resistivity part deals with the basic aspects of electric resistivity measurements: theory, acquisition, converting data to apparent resistivity, modelling, sensitivity analysis and inversion. The theory part is supplemented by one afternoon of practical work with computer exercises for modelling and inversion of DC resistivity data.

The borehole-logging part deals with the most important types of borehole logging data to lithological interpretation and integration with resistivity and seismic survey data. In the borehole logging exercises the use of gamma-ray, resistivity, sonic, density and neutron logs for rock type determination are explained. Combined logs are used to interpret the rock type, and link the log data to acoustic, elastic, and electrical rock properties. The practicals cover the interpretation of the lithology from log data, the derivation of elastic rock properties and depth calibration of seismic data of the seismology part of the course.

Another part of the course consists of an Integrated Assignment in which the students will get some raw seismic, DC-apparent-resistivity and logging data, and they need to use these data to create images of the subsurface that characterize the subsurface in terms of lithologies and the possible fluids therein.