Improved characterisation of hydrocarbon reservoirs
The ever increasing demand for gas and oil has intensified the search for underground hydrocarbon reservoirs. As the easily accessible reserves become depleted, exploration has inevitably shifted to reservoirs located in more complex bedrock. Given the high cost of such ventures, accuracy is of the utmost importance. The Energy, Environment and Sustainable Development Programme funded a key RTD project on this subject entitled SIMBA. The project participants included experts from both industry and academia. The goal was to develop advanced methods to characterise underground hydrocarbon reservoirs. Pioneering research at Ark Geophysics Limited in the United Kingdom sought to extend upon the conventional approach, which is based solely on seismic data. Using an empirical approach, they incorporated two additional geophysical parameters density and electrical resistivity, to combine with the seismic velocity data. The work was facilitated by the existence of the SIMBA Rock Property Database. The major advantage is that the density data provides important insight into the features of basalt layers. This is complemented by feedback for the layers above and below the basalt formation from the electrical resistivity data, which is determined using Magnetotellurics (MT). The team at Ark Geophysics Limited combined these elements into a two-dimensional joint inversion scheme. Tests of the scheme during SIMBA indicated that the level of uncertainty in the inversion of the complete dataset could be significantly reduced.
