Seismic modelling of brecciated sand injectite systems: sensitivity analyses and uncertainty

Project description
Sand injectites reservoirs contain significant economic hydrocarbon reserves in the North Sea. The presence of sand dykes, sills and brecciated units provide a complex 3D trapping mechanism and increase vertical connectivity within significant vertical successions. This often results in hydrocarbon columns that are thicker than conventional stratigraphic/ structurally trapped reservoirs.

While injectite breccias have been extensively described in the subsurface (Duranti et al. 2002, Huuse et al. 2003, Duranti & Hurst 2003, Jonk et al 2005, Templeton et.al 2006, Lonergan et al 2007, Satur et al 2020), they are less understood and quantified than other sand injectite facies. During recent years, the characterisation of injectite breccias in outcrop has provided valuable insight into their architecture and properties (Zvirtes et. al, 2019 and 2020). Further data and interpretation by the Sand Injectite Research Group at the University of Aberdeen (SIRG) have quantified the geometries and N/G of brecciated units and incorporated this into a static geological model of a key outcrop containing significant injectite breccias (Figure 1).

Fig. 1: Tumey Hill geological concept and model

Photo:

SIRG/Brettle

This project will use the geological model of Tumey Hill to generate seismic models of a brecciated sand injectite system and perform via seismic modelling sensitivity analyses varying geological parameters (N/G, background stratigraphy, different proportions/ orientations of facies, ec) and geophysical ones (frequency content, wavelet, survey azimuth, etc).

The principle aim of this is to improve the identification, mapping and quantification of brecciated units from seismic data.

Additional scope that could be incorporated:
- The generation and seismic modelling of different static model scenarios
- Comparisons with subsurface seismic data from the North Sea where injectite breccias are known to exist.
- The 4D response to brecciated units, using the results of flow-simulated models of known fluid densities.

Proposed course plan during the master's degree (60 ECTS):
GEOV272
GEOV274
GEOV261
GEOV361
GEOV300
GEOV302
SDG207

Prerequisites
Prospective students should have a strong interest in geological and seismic modelling, and an understanding of the importance of performing sensitivity analyses and assessing uncertainty.

External data
Sand injectite data and the static model/ workflows will be provided by
SIRG (U of Aberdeen).

Field- lab- and analysis work:
The work will be carried out in one of the two seismic labs. A field visit might be possible, and access to virtual field
models will be provided.