BOMS Project – Borehole Monitoring Solutions for CO2 Storage Wells

A critical aspect of managing CO2 storage sites is ensuring the integrity of the storage containment. One innovative approach to this challenge involves the use of optical fibres for continuous downhole monitoring in cased wells. These fibres, equipped with Distributed Acoustic Sensing (DAS) and Distributed Strain Sensing (DSS) technologies, can provide valuable data on strain and elastic wave velocity within the geological formation and the cement surrounding the casing. This information is essential for assessing the stability and containment of stored CO2.

Despite the potential of this technology, two significant challenges remain unresolved:

1. Installation Complexity: How to effectively deploy optical fibres in wellbores with multiple casing sections.
2. Data Interpretation: How to accurately interpret the data collected from the fibres to monitor CO2 storage conditions.

The DTU Offshore team, as part of the broader BOMS (Better Offshore Monitoring Systems) project, is focusing on the second challenge. While rock physical inversion is a promising method for interpreting fibre data, selecting the most suitable models for different lithologies is not straightforward. To address this, the project will conduct laboratory experiments where CO2 is injected into controlled lithologies. During these experiments, strain and elastic wave velocities will be measured using optical fibres. By comparing the inversion results with known values, the team aims to refine the interpretation process.

The ultimate goal of this research is to develop robust methods for interpreting optical fibre data, enabling the detection of changes in CO2 saturation within the formation. Such changes could indicate CO2 migration, providing early warnings of potential containment issues.

The BOMS project is a collaborative effort involving Gas Storage Denmark, Welltec, BlueNord, GEUS, and DTU Offshore. It is supported by one postdoctoral researcher and is scheduled to run until mid-2026. Funding for the project is provided by InnoCCUS under the 3-P5 BOMS initiative (INNO-CCUS).