Estimating predrill volumes in hydrocarbon exploration involves dealing with geological and technical uncertainties. The prediction of the hydrocarbon column height is widely recognized as the primary driver of uncertainty in volumetric estimates. The oil and gas industry continues to renew efforts to limit such uncertainties because of the potential economic costs of inaccurate estimation, yet estimation of predrill volumes remains an inexact science. This study introduces new empirical data from the Norwegian continental shelf and aims to improve accuracy in hydrocarbon column height prediction. We use column height, trap height, and burial depth data to calculate the degree of hydrocarbon trap fill for each of the 242 studied discovery wells. The data are aggregated into a simple forward probability model to calculate the chance of encountering different ranges of trap fill, based on burial depth and trap height. The distribution of trap-fill ratios clearly correlates with both trap height and burial depth, thus indicating that the same predrill column height distribution should not be used for all prospects. Our findings strongly suggest that the prospect’s dimensions and burial depth should be used alongside other technical subsurface factors to determine the most suitable predrill hydrocarbon column height distribution. The proposed methodology contributes to reducing the largest source of uncertainty, which in turn diminishes the overall uncertainty associated with predrill volume estimation. The methods and lessons learned in this study are also applicable to other hydrocarbon exploration basins outside of Norway.

You do not currently have access to this article.