Seismic interpretation of cretaceous petroleum source rocks in Taranaki basin, New Zealand

Abstract

Source rock sequences that were deposited in the Late Cretaceous period are proved to be responsible for tremendous amount of petroleum found in Taranaki Basin, New Zealand, the only basin that contains commercial reserves, but these sequences have yet been studied much about their potentials in deepwater area. In this study, 2D seismic data in the deepwater area were used to find their distributions and were interpreted their seismic reflection characteristics. Two potential source rock sequences have been recognized; Rakopi sequence, one of the main source rocks in Taranaki Basin, and Syn-rift sequence the sequence which lacks the studies about their potentials. By analyzing the seismic reflection characteristics such as seismic reflection amplitude, seismic terminations, and seismic configurations, depositional environments, sediments deposited at that time, and their source rock potentials are acquired. Rakopi sequence’s seismic reflection characteristics suggest the deposition in fluctuated sea levels deltaic environment that have capabilities to provide a large amount of terrestrial origin source rocks. Syn-rift sequence’s characteristics on the other hand, suggest the rapid deposition by high-density turbidity current which possibly resulted in preservation of source rocks as well.