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Integration of Sequence Stratigraphy, 3D Seismic Data Visualisation and Quantitative Risk Assessment - Towards a Stratigraphic Previous HitTrapNext Hit Exploration Portfolio in Cooper-Eromanga Basin, South Australia


 Takeshi Nakanishi1, Simon C. Lang2

(1) Adelaide University, Adelaide, Australia (2) University of Adelaide, Adelaide, Australia

 The future for petroleum exploration in the predominantly non-marine Cooper-Eromanga Basin of onshore Australia, lies in the identification and appropriate risk assessment of stratigraphic traps. Using an integrated approach of sequence stratigraphy and 3D seismic data visualisation, a variety of stratigraphic Previous HittrapNext Hit prospects were identified in the Permian and the basal Jurassic successions.

The geologic chance factors for an effective stratigraphic Previous HittrapNext Hit include reservoir, top seal, lateral seal, bottom seal within each depositional Previous HitsystemsNext Hit tract, the seal effectiveness of the adjacent depositional Previous HitsystemsNext Hit Previous HittractsNext Hit and the appropriate spatial arrangement of these factors. To assess the chance of geologic success, the confidence values for the existence of geologic chance factors were estimated according to the genetic-stratigraphic interval (e.g. lowstand, transgressive, highstand Previous HitsystemsNext Hit Previous HittractsNext Hit). For probabilistic reserves estimation, geologically reasonable ranges were estimated for each parameter employing Monte Carlo simulation to calculate the reserves distribution.

When a series of possible exploration portfolios, including single or multiple prospects from a prospect inventory are plotted regarding the chance of geologic success vs. the mean value of the reserves estimate, an efficient exploration frontier emerges. The portfolio candidates on the efficient exploration frontier were assessed with regard to the expected net present value (ENPV) using a simple cash flow model. The results indicate that appropriate portfolios include multiple prospect exploration especially with lowstand Previous HitsystemsNext Hit tract plays using multiple exploration wells. The portfolio construction approach for stratigraphic Previous HittrapNext Hit exploration should be made consistent with conventional play Previous HittypesTop, to enable an assessment of all exploration opportunities.