The Impact of Seismic Interpretation Methods on the Analysisof Faults: A Case Study from the Snøhvit Field, Barents Sea

Abstract. Five seismic interpretation experiments were conducted on an area of interest containing a fault relay in the Snohvit field, Barents Sea, Norway, to understand how interpretation method impacts the analysis of fault and horizon morphologies, fault lengths, and vertical displacement (throw). The resulting horizon and fault interpretations from the least and most successful interpretation methods were further analysed to understand the impact of interpretation method on geological modelling and hydrocarbon volume calculation. Generally, the least dense manual interpretation method of horizons (32 inlines (ILs) x 32 crosslines (XLs), 400 m) and faults (32 ILs, 400 m) resulted in inaccurate fault and horizon interpretations and underdeveloped relay morphologies and throw that can be considered inadequate for any detailed geological analysis. The densest fault interpretations (4 ILs, 50 m) and auto-tracked horizons (1 IL x 1 XL, 12.5 m) provided the most detailed interpretations, most developed relay and fault morphologies and geologically realistic throw distributions. Analysis of the geological modelling proved that sparse interpretation grids generate significant issues in the model itself which make it geologically inaccurate and lead to misunderstanding of the structural evolution of the relay. Despite significant differences between the two models the calculated in-place petroleum reserves are broadly similar in the least and most dense experiments. However, when considered at field-scale the magnitude of the differences in volumes that are generated solely by the contrasting interpretation methodologies clearly demonstrates the importance of applying accurate interpretation strategies.