The discussion paper raises two main concerns:

1. The data provided and described are insufficient to recreate our case study models to examine them independently, and

2. Authors do not believe there is sufficient evidence for capillary seal in the case studies, specifically:

   1. Due to unaccounted uncertainty in vertical seismic resolution, the juxtaposition geometry might mean that fault rock is not supporting the column.

   2. Based on gamma ray values in one well log, the authors believe the Eumeralla Formation provides juxtaposition seal in the Boggy Creek field, rather than fault seal as per our original interpretation.

The main objective of our paper was to investigate the fluid property effects on fault-rock seal. We made a deliberate choice to demonstrate the uncertainty effects due to fluid properties, separate from the overall uncertainty of structural interpretations. The aim was therefore to show the working, which could be reapplied in other localities, rather than provide a comprehensive geological description of these already well-studied fields. However, the considerations suggested by the authors do not change the overall interpretation of our model.

Data availability

The data used for this study principally consist of historic well logs and reports, 3D models, and seismic surveys. The well logs and reports (GSV 2012) are publicly available, and contain all information needed to address these specific concerns: define stratigraphy, GWCs, flow units and V-Shale curves. The 3D models used in our study are described in detail in the original papers (Lyon et al. 2004, 2005a, 2005b, 2007; Ziesch et al. 2017). The models were combined with 3D seismic surveys supplied by CO2CRC (Balnaves, Haselgrove OGF93A, ONH01 and Curdie Vale). Seismic surveys were converted to depth using published velocity models (Lyon et al. 2004; Ziesch et al. 2017) to check the validity of key structures important for …