Structural Modeling of the Maui Gas Field, Taranaki Basin, New Zealand

Abstract

3D seismic and well log dataset were used jointly to build a structural model of the Late Cretaceous to Pliocene sedimentary sequence in the Maui Gas Field, to predict structural mechanics in the Taranaki Basin with geostatistics. Three phases of tectonic movements affected by faulting in this field were identified by this structural model: Late Cretaceous to Palaeocene rifting phase, Late Eocene to Miocene compressive faulting phase, and Plio-Pleistocene differential (compressive faulting in Maui South, normal fault activity in Maui North) faulting phase. Different phases of tectonic movements resulted in different structural patterns, Early Oligocene formations have abundant normal faults with slight slip and higher dip angles (40°-70°), and lower dip angle in the north (10°-15°) than in the south (15°-20°); Mid-Oligocene to Late Miocene formations contain low angle reverse faults (20°-40°), showing the structures in this period were affected by compressive stress on the whole; structural inversion occurred during mid-Oligocene to Pliocene, indicating the structural stress was contraction first and extension later in this period.