Series: Navigating Carbon Dioxide Plume Flow in the Subsurface, A Reservoir Engineer’s Perspective.

Article 1: Unlocking Safe Carbon Capture: Bridging the Gap in Subsurface Fluid Modelling

In the domain of subsurface fluid dynamics, a wealth of knowledge is shared between the realms of hydrocarbon exploration and Carbon Capture and Storage (CCS) initiatives. Over decades of oil and gas exploration, invaluable insights have been garnered into the intricate workings of sedimentary basins, geological formations, and reservoir engineering practices.

This extensive knowledge base serves as a cornerstone for CCS projects, offering a robust foundation upon which to build and optimise carbon storage solutions. From offshore to onshore environments, the methodologies, technologies, and best practices honed in the hydrocarbon industry prove highly adaptable to the challenges of CCS endeavours.

Advanced techniques in geological mapping, geophysical surveys, and reservoir engineering find new applications in the context of CO2 storage. Likewise, some expertise developed in designing and managing pipelines, wells, and reservoirs for hydrocarbon extraction is directly transferrable to the task of safely injecting and storing CO2 underground.

4D seismic is used not only for hydrocarbon extraction, but also to monitor the injection of CO2. This example shows seismic amplitudes used for plume monitoring at Sleipner.

Data taken from the 2006 monitor survey.  Sleipner 4D Seismic Dataset provided by the Sleipner Group on the CO2 DataShare.  Data Owners:  Equinor, PGNiG & Orlen.  License:  CO2DataShare.

However, amid these shared principles and practices lies a fundamental divergence in behaviour between injected CO2 and natural hydrocarbons in subsurface environments. This discrepancy underscores the need for meticulous modelling and simulation of CO2 plumes to ensure the safety and efficacy of storage operations.

This series embarks on an exploration of the parallels and disparities between modelling CO2 movement and hydrocarbon migration underground. By delving into these intricacies, we aim to enhance the precision and reliability of subsurface fluid flow simulations for CO2 storage projects, paving the way for sustainable carbon management solutions in the fight against climate change.

Key Differentiators:

  1. Deciphering the supercritical state of CO2: Understanding the properties of supercritical CO2 is pivotal for accurate subsurface modelling. Unlike conventional hydrocarbons, CO2 can exist in a supercritical phase, influencing its behaviour in storage formations.
  2. Grasping CO2 flow physics: The fluid dynamics of CO2 differ significantly from those of hydrocarbons due to variations in density, viscosity, and phase behaviour. A nuanced understanding of CO2 flow physics is imperative for effective modelling and prediction.
  3. Ensuring caprock integrity to prevent leakage: Maintaining the integrity of caprock formations is crucial for preventing CO2 leakage into overlying strata. Unlike hydrocarbon reservoirs, CO2 storage sites require robust sealing mechanisms to mitigate environmental risks.
  4. Navigating rock heterogeneity: Geological heterogeneity poses challenges in modelling CO2 plumes, impacting fluid flow pathways and storage capacity. Accurate characterisation and modelling of rock heterogeneity are essential for reliable subsurface simulations.
  5. Considering spatial and temporal scales: Spatial and temporal scales play a significant role in CO2 plume dynamics, influencing migration patterns and reservoir behaviour. Incorporating these scales into modelling frameworks is essential for predictive accuracy.

A deeper understanding of these differences is instrumental in advancing the development of robust subsurface fluid flow simulators tailored to CO2 storage projects. By bridging the gap between theory and practice, we can pave the way for more effective carbon management strategies in the pursuit of a sustainable future. Look out for our next article which will delve deeper into deciphering the supercritical state of CO2.