Seismic charateristics of igneous intrusions in Canterbury basin, New Zealand

Abstract

In New Zealand, the volcanism commenced in the Late Cretaceous to Pliocene intermittently and locally and caused igneous intrusions in the Canterbury basin, one of the petroliferous frontier basins in New Zealand. In this study, 3D seismic data of WAKA 3D were used to interpret seismic reflectors of igneous intrusions. Five sills units and three morphologies of sills were discovered including; a saucer shaped sill, an inclined sheet and a layer-parallel sheet. Using sill geometries and sill stratigraphic positions, the inferred magma flow direction and potential sources were derived for each sill unit. Plus, an analysis of sill geometry and seismic characteristics of overburden rocks proposes saucer shaped sill induced the dome like structure called forced fold above which could be a trap for petroleum systems. Additionally, 2D seismic data and well data used to make correlation integrated with the seismic-stratigraphic analysis imply that emplacement timing of sills has started since Miocene which overlapped to the time of hydrocarbon generation. Consequently, forced folds induced by saucer shaped sill can possibly be a potential trap.