Optical Sensing of CO₂ Geological Storage Using Distributed Fiber-Optic Sensor: From Laboratory to Field-Scale Demonstrations

Abstract

An innovative monitoring system using distributed fiber optical sensing (DFOS) technology based on hybrid Brillouin–Rayleigh backscattering is first proposed to measure small strain profiles from core-scale experiments to field tests. The surface of a sandstone specimen is twined and glued with one single-mode fiber (SMF) as well as four conventional strain gauges. A preliminary laboratory experiment is implemented to testify to the sensing effectiveness of this proposed hybrid DFOS system. Laboratory experiments indicate that the measured strain via SMF along the heterogeneous Tako sandstone core surface coincides well with conventional strain gauges and better tracks injected CO2 fronts. Moreover, this novel DFOS-based optical fiber cable has been deployed behind the well casing for detecting impacted zones along the well depth direction in an actual 300 m-deep field well. Field testing shows that the extent of the deformed zone induced by injected CO2 is successfully monitored and quantified in terms of measured in situ strain profiles. This first-hand hybrid DFOS system and lab-field findings can quantitatively evaluate wellbore–caprock integrity by providing real-time in situ strain signals in various Earth geoenergy-related fluids injection, storage, and extraction sites.

Review on Carbon Capture, Utilization, and Storage for Enhancing Gas Recovery

“…Monitoring and analyzing geotechnical responses is a significant challenge in implementing field-scale carbon dioxide (CO 2 ) storage projects. These responses, including deformation (strain) and temperature changes induced by CO 2 injection, are subsurface and ground-level. – …”

Influence of Reservoir Spatial Heterogeneity on a Multicoupling Process of CO2Geological Storage

“…Greenhouse gas emissions from 2009 to 2019 were higher than in any previous decade, and limiting global warming is a huge challenge . Injecting carbon dioxide (CO 2 ) into geological structures is a technology that can effectively reduce CO 2 emissions. − There are currently a lot of research studies on various application scenarios of carbon capture, utilization, and storage (CCUS). − However, the geological structure naturally has spatial heterogeneity, and this spatial heterogeneity is usually manifested as the difference in reservoir rock properties such as reservoir rhythm, permeability, porosity, and capillary parameters. − At the same time, there may be interlayers in the reservoir, which divide the reservoir into multiple small layers with fluid and pressure discontinuity. , The spatial heterogeneity of the reservoir will significantly affect the flow and heat transfer of CO 2 . Thus, studying the influence of reservoir spatial heterogeneity on CO 2 storage is of critical significance when selecting a site for CO 2 geological storage, predicting fluid state, and optimizing engineering parameters.…”

Real-Time Monitoring of Gas-Phase and Dissolved CO2 Using a Mixed-Matrix Composite Integrated Fiber Optic Sensor for Carbon Storage Application

“…Waveguide-based fiber optic (FO) sensors, on the other hand, have unique characteristics such as flexible design for in situ and in vivo analysis, remote readout capability over hundreds of kilometers, and potential miniaturization for a low-cost mobile sensing system. − Leveraging these advantages, several different FO-based sensors (or packaging) have been developed and successfully deployed for real-time monitoring of CO 2 at geologic sequestration . For example, Sun et al proposed distributed FO sensing technology based on hybrid Brillouin–Rayleigh backscattering in order to assess its applicability and workability in a real-world geological environment. Bao et al established a long-period grating FO sensor and proposed a sensing mechanism based on the different refractive index (RI) of the surrounding medium to distinguish between supercritical CO 2 and CO 2 -saturated brine.…”