The main objectives of the Permian sandstone study are to undertake discontinuity analysis using LiDAR scans and to provide high-quality 3D images for further stratigraphical study, particularly where outcrops are inaccessible. The study also links with the Permo-Trias cross-cutting project, to provide detailed geological information to assess the suitability of Permian and Triassic strata for carbon sequestration and to create 3D property models for flow modelling of carbon dioxide (CO2).
Locations of potentially suitable sandstone outcrops were identified by interrogating several BGS datasets and, following consultation with hydrogeological and mineralogical colleagues, six outcrops were scanned in the Eden Valley in Cumbria between April and July 2010 (Figure 1). The locations of these outcrops presented a number of challenges, including access issues, health and safety risks and technical problems with data acquisition.
The coloured LiDAR scans were used in order to create digital terrain models (DTMs) and virtual outcrop models (VOMs) of the outcrops (Figure 2). In turn, these models were used to create 3D S-grid facies models to be used for CO2 flow modelling, as part of research into carbon capture and storage in sandstone reservoirs (Figure 3).
The main issues with the LiDAR scans carried out within the Eden Valley were the locations of the scan sites themselves and the problems with GNSS availability. The proximity of the scanning location to the outcrop was initially too close for the scanner to resolve (less than 5 m), therefore scans needed to be carried out from across the other side of the river. However, access to these locations was at times treacherous, made over long distances and time consuming.
The final locations themselves were not without problems either; they were tree covered and highly vegetated. This in turn caused problems with the GNSS, either due to the availability or viewing of available satellites, or due to the intermittent failure of the telephone link due the remote location. Even switching to the base station and rover method did not guarantee accurate results. Most scans were able to be correctly orientated by re-aligning them using ImAlign.
If you want to discover more then please contact Lee Jones.