Discussion on ‘A knowledge database of hanging-wall traps that are dependent on fault-rock seal’, Geological Society, London, Special Publications, 496, 209–222, https://doi.org/10.1144/SP496-2018-157

Abstract

This discussion responds to the paper by Bretan et al. (2020), specifically mentioning two issues. The first has to do with open science and the accessibility of datasets so that other scientists and the public can test and re-evaluate the work done by others. The second issue we raise concerns a specific conclusion presented in the paper, namely the implied assertion that fault-rock seal is the only explanation for observed pressure differentials between two nearby wells in the Oseberg Sør Field (Norwegian North Sea). The paper by Bretan et al. (2020) tabulates thirty-eight hanging wall hydrocarbon accumulations which the authors stated are dependent on some form of fault seal. The locations and a limited amount of supporting data for seventeen of the thirty-eight accumulations are available, but the data that are available are insufficient in most cases to allow for the analysis and conclusions to be verified independently. We acknowledge that in some cases, it is impossible to publish all the data that were used because of confidentiality restrictions. However, many important data that are easy to publish are not available, and we wish to call for a more widespread release of key data when possible. The Oseberg Sør Field is the only case study from the ‘knowledge database’ that is presented with sufficient data to allow an attempt at replication of the paper’s premises. This discussion summarizes attempts to replicate the conclusions for the Oseberg Sør Field and presents some concerns with the inclusion of this field in the table of fault seal cases. The analysis of Oseberg Sør that is presented elaborates on Fristad et al. (1997) and Yielding et al. (1997). The data in these papers are summarized in Table 1. The most notable addition from Bretan et al. (2020) is a structure contour map. A conclusion of these three papers is that a fault-rock seal on Fault-1 supports a pressure differential of 7.2 bars (refer to the map in Bretan et al. (2020) for the location of Fault-1).