Interpretation of magnetic data over tilted basement blocks: an example from the northern North Sea

Abstract

A B S T R A C TThis paper presents a procedure for interpreting magnetic data over tilted basement blocks. The objective of this procedure is to estimate source parameters of a tilted basement block from first-order derivatives of magnetic profile data. The method uses a model consisting of two superimposed infinite contacts with opposite dip. The procedure estimates the location of the crest (intersection of the two contacts) and the susceptibility contrast of the basement block from the total gradient anomaly data using a linear least-squares method. Dip angles of the two contacts are estimated using iterative forward modelling of the tilt derivative anomaly data. The practical utility of the proposed approach is demonstrated using theoretical data and a field example from the northern North Sea.