Multi-temporal InSAR-based assessment of fault reactivation using differential deformation metrics: a case study of the Qarn Alam Field

Fault reactivation due to hydrocarbon production and enhanced oil recovery (EOR) poses geomechanical risks in complex hydrocarbon reservoirs. This study introduces a multi-temporal InSAR-based framework for assessing fault reactivation by analyzing right–left deformation asymmetry across mapped fault traces. The approach combines cumulative and incremental deformation metrics from fault-centered profiles to quantitatively evaluate spatial discontinuities, temporal persistence, and statistical significance. Applied to the Qarn Alam Field in Oman, where long-term steam-injection EOR has resulted in both subsidence- and uplift-dominated deformation, the methodology uses InSAR time series from RADARSAT-2 (2010–2020) and TerraSAR-X (2020–2023). These datasets were processed independently using persistent scatterer techniques, projected to vertical deformation, and merged into a continuous multi-sensor dataset. Results show persistent right–left deformation asymmetry along a Natih fault segment in a subsidence-dominated zone, indicating sustained fault-controlled deformation. In contrast, Shuaiba fault segments in uplift-dominated regions display weaker spatial localization and less temporal persistence of right–left asymmetry, despite higher composite reactivation indices. These findings indicate that fault reactivation signatures are determined by deformation localization and temporal coherence, not by deformation magnitude alone. The proposed framework provides a scalable tool for assessing InSAR-based fault reactivation in low-seismicity, production-affected environments.