| Canterbury Basin is a Cenozoic passive margin basin superimposing on a Mesozoic rift basin. The offshore host can be divided into three tectonic units, i.e. Western Slope, Central Depression and Eastern Uplift based on seismic interpretation and drilling data analysis. The basin has experienced three evolution periods since Cretaceous, the rifting period (K1 to early K2), the passive continental margin period(late K2 to early E3) and the compressed subsidence period (late E3 to now), which brought in different sedimentary sequences. There are two plays in the basin, in which Upper Cretaceous Clipper swamp coal measures and Pukeiwitahi plain coal measures strata are as source rocks and Clipper fluvial sandstone and Herbert and/or Broken River neritic sandstone are as main reservoirs. The paleostructural configuration and the normal faults that formed during the rifting period control the distribution of traps and the direction of hydrocarbon migration. Good conditions of hydrocarbon accumulation are possessed in the draping anticlines and fault-block traps in Central Depression and on the side of Eastern Uplift adjacent to the depression, which are suggested to be the potential exploration areas. |
