Evolution of the Stress and Strain field in the Tyra field during the Post-Chalk Deposition and Seismic Inversion of fault zone using Informed-Proposal Monte Carlo

TL;DR

This paper presents a new Monte Carlo method to efficiently analyze stress and strain evolution in a hydrocarbon reservoir during CO2 storage, aiding risk assessment of faulting that could impact storage integrity.

Contribution

It introduces the Informed-proposal Monte Carlo (IPMC) method for large-scale seismic inverse problems, integrating geological and geophysical data for risk evaluation.

Findings

IPMC reduces computational cost in seismic inversion.

Method provides a framework for fault risk assessment in CO2 storage.

Application to Danish North Sea data demonstrates practical utility.

Abstract

When hydrocarbon reservoirs are used as a CO2 storage facility, an accurate uncertainty analysis and risk assessment is essential. An integration of information from geological knowledge, geological modelling, well log data, and geophysical data provides the basis for this analysis. Modelling the time development of stress/strain changes in the overburden provides prior knowledge about fault and fracture probability in the reservoir, which in turn is used in seismic inversion to constrain models of faulting and fracturing. One main problem in solving large scale seismic inverse problems is high computational cost and inefficiency. We use a newly introduced methodology -- Informed-proposal Monte Carlo (IPMC) -- to deal with this problem, and to carry out a conceptual study based on real data from the Danish North Sea. The result outlines a methodology for evaluating the risk of having subseismic faulting in the overburden that potentially compromises the CO2 storage of the reservoir.