The Malcom distribution analysis method: A consistent guideline for assessing reservoir compartmentalisation from GC fingerprinting

Abstract

Characterisation of reservoirs, as well as studies of reservoir continuity, can be achieved using various techniques. Among these, reservoir oil fingerprinting obtained from analysis of gas chromatograms of crude oils is one of the less expensive and less time consuming methods. However, the technique has some limitations, as uncertainties relating to peak height ratios, classically used as a starting point in current methods, are not well quantified. This paper presents a new statistical method, based on a consistent quantification of the uncertainty from the peak height measurements, which provides absolute distances between fingerprints on a universal scale. It allows the creation of a database of case studies directly usable for comparison purposes in any new project: the knowledge acquired from former studies can be readily employed to set the threshold of composition variability at which barriers/baffles should be invoked. The method is able to discriminate samples even if the amplitude of the compositional differences is about the same as the error in the peak heights, and distances between samples depend neither on the number of peak ratios available, nor on the uncertainty in the peak height measurements.