Three-Dimensional Petrophysical Modelling and Volumetric Analysis to Model the Reservoir Potential of the Kupe Field, Taranaki Basin, New Zealand

Abstract

This study addresses the three-dimensional (3D) petrophysical modelling and volumetric analysis of the Farewell Reservoir in the Kupe Field in the southern Taranaki Basin, New Zealand. The qualitative petrophysical analysis of the Kupe South-1, Kupe South-3, Kupe South-4 and Kupe-6 wells helped to model the lithological and mineralogical composition of the reservoir, while the quantitative interpretation was used to identify the shale volume, porosity type and distribution, and water and hydrocarbon saturations. A 3D petrophysical model was developed on the basis of the petrophysical analysis, and it showed the spatial distribution and propagation of the petrophysical properties within the reservoir formation of the Kupe Field. Moreover, a volumetric analysis was conducted to estimate the gas reserves and probable reserve growth of the Kupe Field. The results indicated that the gross thickness of the studied reservoir formation ranges from 226.47 to 381 m, while the net reservoir thickness is between 12.95 and 140.2 m. The shale volume lies between 17.3% and 22.4%, while the total and effective porosities are between 17.9% and 27% and between 15.1% and 23%, respectively. The study also shows the presence of net pay zones with an aggregate ranging between 12.95 m and 82.45 m with variable hydrocarbon saturations. The hydrocarbon saturation is between 62.5% and 70.8%, while the water saturation is between 29.2% and 37.5%. The volumetric analysis indicates that the Kupe Gas Field contains 654.6 Bcf (18.5 × 109 m3) of gas, while the recoverable gas is estimated to be 389.87 Bcf (11.03 × 109 m3) at 50% probability. The volumetric estimation also confirms that the possible reserve growth of the Kupe Field is expected to be 60.8 Bcf (1.72 × 109 m3) of gas in the case of 50% probability estimation. The 3D models not only validate the drilled wells used in the study but also indicate future prospective zones for drilling. The results inferred from the integrated study reveal that the Farewell Formation can be characterized as a good reservoir and has potential for future drilling and further development.