Internal structures of salt diapirs and their seismic signatures: a modelling study

Evaporites (commonly referred to as salt) are unique sedimentary rocks. They flow as a viscous fluid at typical geological time scales and strain rates. This salt flow leads to the development of major structures in sedimentary basins such as multi-kilometre tall diapirs and salt walls and hundreds of km wide salt sheets. These structures are often geometrically complex with variable internal and external geometries (Fig. 1)

Supervisors

Main supervisor: Leonardo Muniz Pichel, UiB-GEO
Co-supervisor: Isabelle Lecomte, UiB-GEO
Co-supervisor: Tina Kaschwich, NORSAR

Project description

The internal complexity of salt structures is caused by the different mechanical properties of different evaporites (e.g., halite, anhydrite, K-Mg salts), which in turn controls how they deform and are distributed within diapirs and other deformed salt bodies. This internal complexity is, however, often unresolved by seismic imaging due to the high seismic velocity and high-strained nature of salt structures, their complex external geometries and commonly steeply-dipping beds (Jones and Davison, 2014; Jackson and Hudec, 2017). Understanding the internal geometry of salt structures is of fundamental and societal importance as there is currently an increasing interest in the utilization of salt structures for H2/CH4 storage, and geothermal energy (Daniilidis and Herber, 2017; Duffy et al., 2022) (Fig. 1), as well as supra-salt structures for CO2 storage, in particular in the North Sea.

Figure 1: Synthetic model showing the applications of salt tectonic structures for energy transition technologies, e.g., H2/CH4 storage in salt caverns, CO2 storage, geothermal and hydrocarbon exploration (adapted from Duffy et al. 2022).
Figure 1: Synthetic model showing the applications of salt tectonic<br>structures for energy transition technologies, e.g., H2/CH4 storage in<br>salt caverns, CO2 storage, geothermal and hydrocarbon exploration (adapted from Duffy et al. 2022). Photo: from Duffy et al. 2022

This project will combine high-resolution (20-50 m) state-of-art 2D numerical models of salt tectonics and diapirism (Fig. 2) with seismic modelling (Point-Spread Function - PSF - based convolution) to understand the seismic response of intra-salt lithologies within different types of salt structures. The student will perform sensitivity analysis of key geological parameters such as the density, thickness, stratigraphy of evaporite units and external salt geometry, as well as geophysical parameters (frequency content, wavelet, illumination, incident angle, etc). The seismic models will then be compared to a set of salt structures from the North Sea, Barents Sea and/or Santos Basin, Brazil.

This integrated approach will allow us to improve the often-challenging identification and mapping of intra-salt units and the internal and external diapir geometry in seismic data. This can contribute to de-risking underground energy (H2 and CH4) storage and, ultimately to mitigate society’s impact on climate change.

Figure 2: examples of intra-salt lithological heterogeneity from seismic data (Santos Basin, adapted from Rowan et al., 2019) and salt mines (adapted from Jackson and Hudec, 2017) and 2D numerical models from UiB that will be used in this project.
Figure 2: examples of intra-salt lithological heterogeneity from seismic<br>data (Santos Basin, adapted from Rowan et al., 2019) and salt mines<br>(adapted from Jackson and Hudec, 2017) and 2D numerical models<br>from UiB that will be used in this project. Photo: Leonardo Pasqualetto, UiB

Field-, lab- and analysis work

The work will be carried out in one of the seismic labs for data and software access.

Proposed course plan

To be discussed with the prospective student based on background and interests; a preliminary list of possible choices is given below (should amount to a 60-ECTS in total):
GEOV261 / Basin analysis and subsurface interpretation -10
GEOV251 / Advanced Structural Geology - 10
GEOV272 / Seismic Interpretation – 10
GEOV364 / Advanced basin analysis – 5
GEOV352 / Field course in reservoir geology – 5
GEOV361 / Sequence Stratigraphy and Source-to-Sink - 10
GEOV362 / Integrated tectonics and sedimentology field course – 5
GEOV302 / Data analysis in earth science – 10

Last updated: 23.06.2026