Crossing conjugate normal faults in field exposures and seismic data

Abstract

Crossing conjugate normal faults are common in many hydrocarbon- producing basins. In these settings, they exert a range of influences from trapping hydrocarbon accumulations to producing permeability anisotropy by preferentially enhancing or reducing permeability, and reducing effective thicknesses of seal and reservoir units. The fault intersection region is typically poorly imaged with seismic data, and consequently, developing a coherent interpretation of deformation in the intersection region is difficult. In this article, we explore crossing conjugate normal faults across two orders of magnitude of displacement using clear field exposures from the western United States and subsurface examples from the Jeanne d'Arc Basin, offshore Newfoundland. We demonstrate common structural elements and potential pitfalls associated with interpretation of crossing conjugate normal faults, and emphasize the widespread and often unecognized occurrence of these structures. Copyright © 2009. The American Association of Petroleum Geologists. All rights reserved.