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Department of Geology, University of Wales College of Cardiff, PO Box 914, Cardiff CF1 3YE, UK
Whilst it may be easy to describe and quantify a sedimentary succession from outcrop or core, using these data to predict sedimentary facies, diagentic features and fracture distribution in unsampled areas still requires considerable intuition. Frequently, at the current state of geological knowledge, reservoir datasets must be supplemented by consideration of analogues. The aim of this paper is to sound caution on the indiscriminate use of analogues in reservoir geology.
Analogues used in reservoir geology fall into three main categories: comparisons with modern depositional processes, experimental simulations, and rock record analogues. All analogues used for reservoir geology suffer from limitations due to the physical and temporal scales at which the comparisons are made. Difficulty in selecting appropriate analogues results from the amount of interpretation of the nature of the reservoir required before an analogue may be selected, the large number of degrees of freedom in the processes of formation of reservoir rocks, and the limited numbers of well-documented analogues which are easily available.