High-Resolution Fiber-Optic Sensing System for 4D Mapping, Detection, and Characterization, and Integrity Assessment of Legacy Wellbores for Carbon Storage

Underground carbon dioxide (CO2) storage is one of the promising solutions in the efforts on mitigating the adverse effects of climate change due to greenhouse gas emissions. Prior to implementation of a major carbon storage project, it is imperative to determine and assess risks associated with both the detection and integrity of legacy wellbores of the target site, and if economically feasible, substantially mitigate these risks. The objective is to determine if the site is suitable for reliable carbon storage, with negligible odds of CO2 leakage into the atmosphere. In this connection, DOE is seeking development of new sensors, technologies, and tools that enable detection of “legacy wellbores that lack a steel surface casing” (“undetectable legacy wellbores”), and/or assessment of “the integrity of legacy wells in which conventional logging tools cannot provide the needed information” ( “undocumented legacy wellbores”). IFOS proposes to develop an innovative, cost-effective, distributed, and high-resolution fiber-optic-based 4D (spatial and temporal) imaging, mapping, and detection system – Well*Sense™ - that will enable detection and localization of currently undetectable legacy wellbores, and integrity assessment of the undocumented legacy wellbores. IFOS’ Well*Sense™ platform will be further enhanced by developing and applying application- optimized Artificial Intelligence (AI), Machine Learning (ML), and computational models. Well*Sense™ will provide an excellent wideband dynamic range through IFOS’ innovative high signal-to-noise-ratio (SNR) optoelectronics architecture, advanced multiplexable photonic sensors, and a verified measurement resolution, down to 1 femtometer (fm) wavelength shift, equivalent to a pressure change of 0.00013 [psi], enabling high-resolution 4D imaging, mapping, detection, localization, and integrity assessment of undetectable and undocumented legacy wellbores. Results from Phase I development and tests will guide Well*Sense development in Phase II and beyond. The major application is determining and assessing the integrity of currently undetectable and undocumented legacy wellbores, which can reduce investment risks and deliver significant cost savings. The system will have numerous spin-off applications in traditional oil & gas and geothermal industries.