Fiber Optic System for Direct Detection of Carbon Dioxide Leakage in Carbon Storage Wells

Project Overview

This feasibility study focused on the development of new fiber for distributed chemical sensing that will allow direct detection of carbon dioxide (CO₂₎ leakages in the environment. This is particularly important for monitoring well integrity for carbon capture and storage, which can provide early warning for an incoming well failure and potential subsequent CO₂ leaking. We proposed Raman or infrared (IR) interrogation within gas-filled Holey Fibers (HoFs) interleaved with Fiber Bragg Grating (FBG) sections, so that the location and concentration of the gases would be provided simultaneously. The methodology would overcome current roadblocks to using fiber optics for CO₂ (and other gases) detection in wells with direct in-situ measurements of concentration along with other important parameters such as temperature and pressure.

We were able to assess commercially available IR/Raman hollow core fiber and demonstrated detection of CO₂ through them in our controlled environment setups at various pressure conditions. We have also established the ability of drilling precisely with femtosecond (fs)-laser side holes to enable penetration of CO₂ into the hollow core fiber and reduce diffusion rates. Open joint collars were also explored with double functionality: to obtain splice to solid core fiber critical for field deployment and create gas ingress locations. Both diffusion-only and pressurized fiber system have been constructed following COMSOL based semi-hybrid optical /fluidodynamics models. FBGs have been identified and procured and characterized. Along the work we leveraged internal modeling/design, photonics/laser characterization, optical fiber fabrication, and advanced manufacturing lab capabilities to design, develop and test in-house components or assemblies. Our results indicate the potential of HoF for CO₂ downhole direct detection.

Mission Impact

The success of a fiber based gas detection with slotted HoFs and FBGs distribute sensors will allow us to greatly enhance our current capabilities in carbon economy and engineering, climate resilience, and laser optic technology. The proposed system could be in place before well abandonment, and provide autonomous, real-time surveillance after a CO2 storage site is closed. The work directly addresses DOE's energy and environmental security missions and develops science and technology capabilities to meet future national security challenges.

Publications, Presentations, and Patents

W. Delmas et al., "Simulated and Experimental Demonstration of CO2 Detection Using Sequentially Drilled and Non-Drilled Open Air Photonic Fiber Segments." SPIE Photonics West, San Francisco, CA, January 22-27, 2022.

IL-13495O1, "Autonomous fiber optic system for direct detection of co2 leakage in carbon storage wells," submitted as patent on 08/27/21.