--> Are Outcrop Analogues Useful in Reservoir Facies Modelling?

AAPG ACE 2018

Datapages, Inc.Print this page

Are Outcrop Analogues Useful in Reservoir Facies Modelling?

Abstract

Depositional facies represent a primary (textural) control on the distribution of porosity, permeability and related properties in siliciclastic reservoirs. Real facies distributions may be spatially complex but they are non-random; they show patterns, inter-relationships and scale characteristics that have a degree of predictability. As such, facies modelling is routinely employed as an integral part of reservoir modelling workflows designed to populate petrophysical properties in the unknown volumes between and beyond well data.

In practice however, facies model design is subjective; the appropriateness of chosen facies components and modelling parameters are difficult to validate. To address this loose subjectivity, geological analogue data (outcrop, modern or subsurface) are commonly invoked to constrain or benchmark facies models. This is a reasonable approach in principle but the selection of analogues, the data available from them, and the way analogue data are applied all have limitations and are subject to bias. So, should we actually be looking to analogues to help us with real-world facies modelling?

This study documents a series of case studies designed to test the impact of using high quality outcrop analogue data to constrain facies modelling in contrasting fluvial and shallow marine reservoirs. In particular, effects on lateral connectivity are investigated and quantified in models intended for dynamic simulation. The specific analogue databases employed are the Fluvial Architecture Knowledge Transfer System “FAKTS” (Colombera et al. 2012) and the Shallow-Marine Architecture Knowledge Store “SMAKS” (Colombera et al. 2016). These case studies highlight certain advantages and pitfalls of analogue usage and suggest guidelines and criteria for effective integration into reservoir modelling workflows.