Evolution of a salt-related listric growth fault near the d-1 well, block 5605, danish north sea: displacement history and salt kinematics

Abstract

The Top Chalk surface and the Tertiary sediments of the Danish North Sea are cut by only a few major faults which are often related to or controlled by the mobile Zechstein salt. A single listric growth fault (the D-1 fault) and its adjacent area have been mapped in detail in order to unravel the fault geometry and kinematics. The spatial distribution of displacements and lateral dimensions of the fault are used to examine the interaction between salt movements and the evolution of the fault. The displacement distribution on the fault is systematic, with contours of equal displacement forming concentric semi-ellipses centred on the point of maximum displacement with displacement decreasing upwards and laterally approaching the displacement configuration for the upper part of an ideal simple blind fault. Furthermore, within the volume surrounding the fault vertical displacement shows similar contour patterns for the hangingwall and footwall, respectively. The lateral displacement variation during fault growth and reconstructed displacement geometries indicate that footwall uplift was mainly a result of salt flow. Despite the complicated nature of salt dynamics the evolution of the D-1 fault resulted in a systematic fault displacement geometry within the rock volume surrounding the fault.