Microseismic Monitoring at the Farnsworth CO2-EOR Field

Abstract

The Farnsworth Unit in northern Texas is a field site for studying geologic carbon storage during enhanced oil recovery (EOR) using CO2. Microseismic monitoring is essential for risk assessment by detecting fluid leakage and fractures. We analyzed borehole microseismic data acquired during CO2 injection and migration, including data denoising, event detection, event location, magnitude estimation, moment tensor inversion, and stress field inversion. We detected and located two shallow clusters, which occurred during increasing injection pressure. The two shallow clusters were also featured by large b values and tensile cracking moment tensors that are obtained based on a newly developed moment tensor inversion method using single-borehole data. The inverted stress fields at the two clusters showed large deviations from the regional stress field. The results provide evidence for microseismic responses to CO2/fluid injection and migration.

Multi-Scale Seismic Measurements for Site Characterization and CO2 Monitoring in an Enhanced Oil Recovery/Carbon Capture, Utilization, and Sequestration Project, Farnsworth Field, Texas

“…For instance, the success of incorporating anisotropy into the modeling implies that the fracture networks are relatively extensive, at least in certain formations. Indeed, HTI behavior may account for some of the microseismicity that has been seen in the formations overlying Morrow B [22]. Likewise, the success of the noise attenuation algorithms may suggest that the industrial operations associated with the active oilfield have the potential to substantially interfere with the seismic processing and interpretation.…”