Dynamic monitoring and effectiveness evaluation of mid-deep coalbed methane hydraulic fracturing via the wide-field electromagnetic method

To address the limited understanding of hydraulic fracture propagation and the challenges in quantitatively evaluating stimulation performance in heterogeneous mid-deep coalbed methane (CBM) reservoirs, real-time monitoring via the wide-field electromagnetic method (WFEM) was carried out on a horizontal well. The results indicate that the hydraulic fractures preferentially propagated along the azimuth of 78°–86° east of north, indicating a maximum horizontal principal stress oriented in the NEE direction. Fracturing fluids migrated dominantly along this direction, effectively covering the perforation interval. The swept area and volume reached 155 000 m 2 and 1 279 500 m 3 , respectively, with an average fracture length of 233 m and noticeable asymmetry controlled by reservoir heterogeneity. Optimal stimulation was achieved at a cluster spacing of ∼31 m, while temporary plugging at 45%–50% of the pumping duration improved intra-stage fluid distribution. WFEM further enabled real-time identification of inter-stage channeling caused by bridge-plug failure. These results demonstrate that WFEM provides quantitative, real-time diagnostics of fracturing processes and supports a closed-loop, data-driven workflow for optimizing stimulation performance in mid-deep CBM reservoirs.