Fault seal juxtaposition and CO2 migration in the early Jurassic Johansen Formation, Horda platform

Introduction:

The Early Jurassic Johansen Formation on the Horda Platform, south of the Troll Field is under consideration as a target formation for CO2 storage (Fig. 1). The prospect is named Aurora. In the study area, the Johansen Formation is present at 2-3 km depth, is overlain by the Amundsen Fm mudstone in some parts, and and by an erosional contact with the Cook Fm in other parts, forming a secondary storage unit (Fig. 2).

The shales and mudstones of the Drake Fm are considered the main caprock and are present within the whole study area. The Aurora storage prospect is located between two major N-S trending faults, Svarta and Tusse. In addition, there are several through-going minor faults trending NW-SE, juxtaposing storage unit and caprock (Figure 1).

The interpretation of the effect of fault properties and related relief is crucial in the assessment of how injected CO2 will migrate and become trapped in the storage unit.

Aim of thesis:

1. Generate a 3D Geomodel of the Aurora storage unit, caprock and intersecting faults
2. Discern how faults will influence injected CO2, i.e., seal capacity, baffling and potential compartmentalisation within the target formation, and influence on CO2 migration pathways.

Objectives:

1. High resolution mapping of faults intersecting the storage unit and caprock.
2. Computing juxtaposition of key targets units across faults using available seismic horizons.
3. Generate and visualise comprehensive fault displacement and attribute (e.g. strike, dip, curvature) analyses in order to inform fault complexity and segmentation history.
4. Classify individual faults based on deformation style, orientation and geometry, timing of activity and influence on CO2 migration. 
5. Depending on student interest, advanced fault analyses, such as quantitative fault seal analysis (e.g. SGR) and fault reactivation analysis may also be explored.  

Tools and datasets:

The student will utilise the GN1001 3D seismic survey that images the Aurora prospect subsurface in addition to well log data from wells that penetrate the target formations. Focus on high resolution mapping of faults will be complemented by existing  in-house seismic horizon interpretation. Seismic interpretation will be conducted using Petrel E&P Software Platform. Seismic horizons and fault sticks will be exported to the Midland Valley Move Software Suite for fault displacement, juxtaposition and attribute analysis.

The student will learn:

Proficiency using Schumberger Petrel E&P Software Platform and Midland Valley Move for a thorough fault analysis. Independent research, academic writing and presentation skills.

Background for project:
The thesis work is integrated in major activities at the Dept. of Geosciences, UiO (5 Masters, 5 PhD’s, 2 Postdocs, 2 Researchers, 5 Profs), evaluating possible storage sites for CO2 sequestration in the North Sea basin. There are close links to the FME NCCS (Norwegian CCS Centre) that collaborates with the Northern Light Project (Equinor, Total, Shell). The latter project plans CO2 injection in the region on behalf of the Norwegian government.