Review Of West Sea Horse Field (Gippsland Basin) Using Quantitative Stochastic Trap Analysis for Stacked Pay

Abstract

Conventional prospect evaluation is commonly based reviewing regional column heights, then assessing the difference between a prospects crest and structural spill point, and in some cases nearby analogue discoveries. Commonly Monte Carlo Simulations or Lognormal Distributions are used to define distributions of trapped column. Depending on the company column, gross rock volume, pore volume, oil and or gas in place distributions are generated. These parameters are then modified by probability of geological success PG. This is estimated/elicited as a combination of factors that may effect the column for instance probability, seal, trap reservoir & fault seal. This methodology has utility in regions with single reservoirs. Unfortunately where there are stacked sands the there are considerable inter segment dependencies. It is often difficult to assessing which prospects to drill in regions with stacked pay in four-way and three-way (fault dependent) prospects. It is proposed that it is better to model the container constraints through a stochastic model of trap geometry, structural elements, top seal and sedimentary stacking. Whilst estimating prospect risks it is vital to ensure that each case is constrained by the fundamental physics of trapping hydrocarbons. In particular ensuring that the seal geometry has been built on an integrated sequence stratigraphic and structural modeling strategy. This strategy will be reviewed base the West Sea Horse field (Gippsland Basin).

AAPG Datapages/Search and Discovery Article #90217 © 2015 International Conference & Exhibition, Melbourne, Australia, September 13-16, 2015