On a method for reducing interpretation uncertainty of poorly imaged seismic horizons and faults using geomechanically based restoration technique

Abstract

To reduce exploration risk and optimize production in structurally complex areas, the geologic interpretation must be based on sound geomechanical principles. Despite advances in 3D seismic acquisition and processing techniques as well as in the availability of computationally robust interpretation software, the challenge associated with interpreting complex structures from seismic reflection data is that highly deformed areas surrounding faults, folds, and salt surfaces are often poorly imaged and therefore their interpretation is highly uncertain. We have developed a methodology that should help geophysicists quickly check the strengths and weaknesses of their interpretation and to automatically reduce the uncertainty in a faulted horizon geometry. Our workflow consisted of restoring interpreted seismic horizons and relating the concentrations of computed deformation attributes to areas of interpretation uncertainty. We used the technique based on an iterative finite-element formulation that allowed unfolding and unfaulting of 3D horizons using physical elastic behavior. A fast algorithm has been developed to automatically correct the interpreted structures in zones that exhibited anomalous deformation concentrations after restoration. This approach is able to mechanically check and reduce uncertainty in a faulted seismic horizon interpretation. Its application to synthetic and reservoir data has a high degree of reliability in the characterization of structurally complex reservoirs. This technique is also applicable to 2D models (geologic cross sections) and 3D models (volume).