This is a CASE Project with Rockfield Global
Key Questions
How do we derisk seals for CO2 storage in subsurface reservoirs?
Background
In order to combat CO2-induced global warming, it is vital for geoscientists to characterise potential sequestration sites. The vast majority of appropriate sites are located in sedimentary basins. Prior to this century, subsurface seismic resolution, modelling capability and data availability provided a limitation on the quality of site characterisation. This meant that fundamental questions such as ‘Is this site safe to store CO2 and how can this be demonstrated?’ and ‘How much CO2 can be safely stored?’ have been poorly answered. In answering these questions, an assessment of the site seal and trap configuration is essential, with processes such as faulting and igneous/clastic intrusion causing a reduction in seal integrity.
Aims of the Project
The aim of this project is to investigate the potential for seal bypass during the storage of CO2 in subsurface reservoirs. Seal bypass may occur where pressure conditions in the reservoir exceed the capillary or hydraulic sealing capacity. This research will focus on the modelling of the impact of clastic and igneous intrusions on the sealing integrity of mudstone and evaporite seals, using an industry leading finite element modelling package (Elfen).
Project Description
The project is designed as a CASE award, and is aimed at derisking clastic and evaporite seals for subsurface storage of CO2. One of the major threats to seal intergrity are intrusions, both of sandstone and igneous materials. These may take the form of dykes and sills. In both cases the seal can be violated by fractures associated with the injection of material (mechanical), or in the case of igneous intrusions by the associated heating and hydrothermal affects in the host material, or cooling of the intrusions themselves (leading to thermal contraction fractures). The investigation will involve a combination of subsurface interpretation using 3D seismic and wells, field analogue studies to measure fracture distributions, and fine element modelling, using Rockfield's leading edge software (ELFEN).
Methods to be used
Two main approaches will be used. Firstly, 3D seismic interpretation of case study areas where CO2 storage prospects are known to be intersected by clastic and/or igneous intrusions. Secondly, the modelling of the impact of these intrusions on the permeability of the seal lithologies through which the intrusions occur. The modelling will be using Elfen, an industry standard finite element package developed by Rockfield Ltd, the case partner. Elfen has been developed at Rockfield for over 30 years as a state-of-the-art Discrete/Finite Element tool for widespread application to a range of industries. It contains a wide range of features for solving multi-physics, multi-scale, highly non-linear problems for both continuum and discontinuum domains. This project requires the use of the additional Elfen fm package, which helps give an understanding of subsurface deformation and stress state to support geological evolution simulations. This is essential to allow for a more complete subsurface interpretation.
Specialised skills required
Seismic interpretation skills (3D) and familiarity with numerical modelling strategies and uncertainties in solving geological problems
Please contact Joe Cartwright on joec@earth.ox.ac.uk if you are interested in this project
CASE partner website https://www.rockfieldglobal.com/
