EXPERIMENTAL STUDY ON CO₂ FORMATION INJECTION MONITORING BASED ON ACTIVE HEATING OPTICAL FIBER

In recent years, with the proposal of the "dual carbon target", reducing carbon emissions and developing new energy sources have become important directions for future sustainable development. CO₂ fracturing and enhanced oil recovery can not only increase reservoir oil and gas production but also achieve geological storage of CO₂, which is highly significant for the exploitation of unconventional oil and gas resources. In this paper, the feasibility of using distributed fiber optic temperature sensing (DTS) to monitor gas migration processes was explored through laboratory CO₂ injection experiments. DTS and other temperature sensors were employed to monitor soil temperature, and active heating DTS technology was used to measure soil moisture content. The monitoring results show that the distributed fiber optic sensor can effectively track changes in soil temperature during CO₂ injection, thereby reflecting the gas migration process. In addition, active heating fiber optic technology can capture variations in soil moisture content distribution, which, combined with soil moisture content measurements, can further indicate the process of CO₂ migration. The experimental results demonstrate that DTS has great potential for application in monitoring CO₂ injection into formations.