Hydrodynamics and Fault Sealing

Abstract

Summary Recent advances in fault seal analysis such as the development of databases of fault rock properties, algorithms for predicting the clay content of fault rocks as well as workflows for calculating transmissibility multipliers for incorporating fault rock properties into production simulation models. This work has been used to create plugins for geological modelling and bespoke fault seal analysis software that allow non-specialists to undertake fault seal analysis. It is, however, imperative to calibrate results from fault seal analysis with static and dynamic data. Cross-fault differences in pressure and/or petroleum water contacts (PWC) are commonly used to identify fault-compartmentalized reservoirs and to calibrate fault seal methodologies. Such data can, however, be easily misinterpreted leading to a misdiagnosis of fault-related compartmentalization. Such misinterpretations are particularly common in environments where hydrodynamic equilibrium has not been reached. Also, cross-fault differences in PWCs in a hydrodynamic environment can provide valuable information that can even occasionally be used to estimate fault permeability. An overview is provided of causes for differences in pressures and PWCs in hydrodynamic environments. The study demonstrates that significant differences in pressure and PWCs can exist across faults that do not have a significant impact on fluid flow on a production time-scale