Demystifying Well Log Quality Control

Abstract

Well logs are essential data used throughout the life cycle of oil and gas upstream assets, from the first evaluation of a reservoir to the planning of its development and management. Yet there are no industry standard processes on how best to assure the quality of the log data stored in organisations’ systems and used decision-making processes. Consequently, logs are often not ready for confident exploitation when they are needed by the geoscientists and engineers. Much critical path time is spent, and additional uncertainty taken on, when the log data are unverifiable, incomplete, incorrect or invalid. This exposes organisations to significant unnecessary hidden risks and costs. A simple framework to formalise log quality control and mitigate these liabilities is proposed. It is based on distinguishing several processes of what is traditionally referred to as log quality control, distributing the tasks to competent persons in the organisation, and phasing the work over time. Critical success factors are the creation and maintenance of a simple system to record log data quality control findings, supported by an explicit, visible and sustained commitment of management to log data quality assurance. Benefits include cost reductions, as savings of subject matter experts’ and exploiters’ time and blunder avoidance, and value increases, as reduced uncertainties and higher confidence levels, allowing the organisation to become more agile and responsive. There are other, less tangible benefits: more effective data workers are generally happier, more productive and more creative, and they make better recommendations.