Monitoring of Carbon Dioxide and Methane Plumes from Combined Ground-Airborne Sensors

A hybrid ground-airborne sensing network for real-time plume monitoring of CO$_2$ and CH$_4$ for carbon sequestration is investigated. Conventional soil gas monitoring has difficulty in distinguishing gas flux signals from leakage with those associated with meteorologically driven changes. A low-cost, lightweight sensor system has been developed and implemented onboard a small unmanned aircraft and is combined with a large-scale ground network that measures gas concentration. These are combined with other atmospheric diagnostics, including thermodynamic data and velocity from ultrasonic anemometers and multi-hole probes. To characterize the system behavior and verify its effectiveness, field tests have been conducted with simulated discharges of CO$_2$ and CH$_4$ from compressed gas tanks to mimic leaks and generate gaseous plumes, as well as field tests over the Farnsworth CO$_2$-EOR site in the Anadarko Basin. Since the sensor response time is a function of vehicle airspeed, dynamic calibration models are required to determine accurate location of gas concentration in space and time. Comparisons are made between the two tests and results compared with historical models combining both flight and atmospheric dynamics.