A seismic-geological approach for fault sealing evaluation: Exploration practice in Kongdian Formation, southern slope of Dongying sag, Jiyang Depression

Fault sealing evaluation is a critical component in the exploration of complex structural reservoirs, where quantitative methods based on 3D seismic data represent a key research focus for reservoir evaluation and drilling deployment in well-sparse areas or early exploration stages. This study proposes an integrated approach for fault sealing evaluation by incorporating geological principles and 3D seismic data. Results indicate that the lithologic configuration of fault walls, shale gouge ratio (SGR), and fault plane dip are the primary controls on sealing capacity. Seismic data analysis and forward modeling reveal significant attribute discrepancies (e.g., amplitude variation rate and frequency anomaly) across fault planes with good sealing performance. By establishing a multivariate regression model that links seismic attribute discrepancy indices, SGR, and fault plane dip to discovered hydrocarbon accumulations, we develop a quantitative characterization method for fault sealing capacity based on seismic attribute variations. This method enables effective evaluation of fault sealing in well-sparse regions. Its application in the Dongying sag of the Jiyang Depression successfully identifies 12 sealing faults, guides the deployment of 8 exploration wells, and achieves an 85% penetration ratio of oil layers, providing robust support for target optimization during early-stage exploration.