Synthetic Transfer Zone Characterization Using Seismic Data, Taranaki Basin, New Zealand

Abstract

Synthetic transfer zones develop between fault segments which dip in the same direction, with relay ramps connecting the fault blocks associated with the different fault segments. The characteristics of the transfer zones are controlled by the lithology, deformation conditions, and strain magnitude. The Parihaka fault is a NE-SW trending set of three echelon faults connected by relay ramps in the Taranaki Basin, New Zealand. The structure in the basin is defined by extension during two episodes of deformation between the late Cretaceous and Paleocene and between the Late Miocene and Recent. To better understand the evolution of a synthetic transfer zone, we study the geometry and secondary faulting between the individual fault segments in the Parihaka fault system using 3D seismic data, and seismic attributes.

A 3D seismic interpretation was conducted to interpret the major faults and surfaces. Unlike standard models of synthetic transfer zones, the Parihaka fault zone is characterized by extensional fault-propagation (drape) folding, which modifies the geometry of the transfer zone. Seismic attributes, including coherence and maximum and minimum curvature were used to understand the detailed geometry and variation in displacement on the individual faults, the nature of secondary faulting along the transfer zones, and the relation between the faults and the drape folds. Because the degree of faulting varies with the stage of development of the transfer zone, seismic characterization of the fault system was conducted for three separate horizons between the Miocene and Pliocene. Coherence and curvature analysis reveal the variation in geometry of the fault system for the different horizons, and the increasing maturity of the transfer zone with depth. Both attributes enhance the visualization of the major and associated secondary faults. The results are also compared to experimental models of transfer zones with associated drape folding.

AAPG Datapages/Search and Discovery Article #90323 ©2018 AAPG Annual Convention and Exhibition, Salt Lake City, Utah, May 20-23, 2018