EAGE Workshop on Petroleum Play Assessment

OMV New Zealand, on behalf of Joint Venture partners PTTEP New Zealand Ltd and Mitsui E&P Australia Pty Ltd, has undertaken a comprehensive four year evaluation of the petroleum potential of New Zealand’s Great South Basin. The Great South Basin (GSB) lies offshore, adjacent to the southeast coast of the South Island of New Zealand (Figure 1). The basin is the largest in the southern New Zealand region, covering an area of approximately 120,000 km2. Water depths range from 100 to 1,500 m, however 80% of the permit area lies in water depths greater than 200 m. Logistics, the amount and quality of available technical data, and environmental considerations are all major factors in exploring large and remote frontier basins. Determining the scope, method and application of projects at the beginning of the evaluation via both sequential and parallel work programmes proved vital in completing a thorough assessment of the basin in the relatively short amount of time available.

Petroleum system modeling is a vital component of exploration that contributes to volumetric and risk assessment at basin, play, and prospect scales. It can be applied during all stages of exploration, from regional charge evaluations for frontier basins with little or no well control to complex charge evaluations for individual prospects or fields within thoroughly explored areas. This paper presents integrated workflows that capture the results from basin and petroleum system analysis and populate play and prospect databases with information on potential hydrocarbon accumulations,including volumetric dependency among accumulations as well as leak connections among hydrocarbon pools. Alternative scenarios for the evolution of the petroleum system are used for capturing prospect risk and hydrocarbon entrapment uncertainty. Adding this stochastic dimension to the play and prospect databases provides a more robust understanding of the full range of possible outcomes that if used properly may provide significant competitive advantage.