Publications

This paper reviews issues with logs which are nonconsonant, that is, they do not investigate the same volume of rocks. Examples of non-consonant logging issues will be reviewed, such as laterolog versus induction logs and the density/neutron combination in gas-bearing intervals. Examples of azimuthal nonconsonance will also be reviewed, as well as the effect of non-consonance on LWD logs. In the last part of the paper, new developments in magnetic resonance and acoustic radial profiling which point the way towards a possible solution to nonconsonance are described. A brief glimpse into the future is given. The paper is based on published literature and the authors personal experience.Most of todays logs are non-consonant and this has the potential to introduce large errors in formation evaluation results. Consonant logs and logs that help understand radial variations of petrophysical properties are being introduced. Software is being developed that will assist in consonant interpretation. Although issues of non-consonance will still trouble petrophysicists for the foreseeable future, a new generation of sensors now helps to understand the radial distribution of formation properties away from the wellbore. Their use will result in more accurate formation evaluation.