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Fault Gouge Seal Models: Sensitivity Study of Petrophysical Inputs
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, Fifth International Conference on Fault and Top Seals, Sep 2019, Volume 2019, p.1 - 5
Abstract
The study presented here investigates uncertainty in the zonation and composition of host rock stratigraphy that are used in SGR models. For a given stratigraphic sequence, logging data from multiple wells were evaluated to characterize stratigraphic uncertainty related to lateral changes in zone thicknesses. Rock composition uncertainty was evaluated through construction of several derivative log curves in both the rock domain (Vshale) and the mineral domain (Vclay). SGR was calculated for a range of fault throws for all 40 combinations of well and log inputs. As expected, SGR outcomes varied dramatically between cases using Vclay and Vshale inputs, often by a factor of two. This difference could translate to nearly an order of magnitude difference in across-fault pressure differential using published SGR-pressure transforms. This study demonstrates that uncertainty regarding which well(s) and petrophysical input(s) to select for SGR analysis is large enough to influence interpretation of fault zone barriers, baffles, and leaks.