The Importance of Fault Analysis in Prospect Volumetrics and Screening

Abstract

Inaccurate volume assessments can lead to expensive drilling of low volume targets or, more often, the by-passing of potentially economic prospects. It is therefore critical for efficient exploration that we have confidence in the approaches being applied. In this paper we will examine gross rock volume approaches derived from top reservoir surface form, discounted for net-to-gross and effective porosity (a very common technique) and 3D model creation linked with stratigraphic population and volumetric analysis (with single, low/mid and high stratigraphic cases, a less common approach but becoming more so). We compare and contrast these techniques and assess the reliability of the resultant volume estimates. Due to recent advances in 3D modeling, useful geological models for prospects can be produced more quickly, and more recent advances allow the automated identification of 3D spill points on faulted traps which can be linked to computations of volumetrics. Linking these techniques to stochastic stratigraphic population routines provides a powerful technique to independently assess the value of the different approaches and identify the key factors that need to be considered when assessing which technique to use in a particular geological setting or the likely accuracy of the volume estimate technique being applied.