Along-Fault Flow Processes and Prediction

Rob Knipe¹, Steve Freeman¹, Simon Harris¹, Russell Davies², Quentin Fisher¹, Christine Souque¹, Michael Welch¹, and Gavin Lewis^3
1Rock Deformation Research, Earth Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
²Rock Deformation Research, PO Box 2998, McKinney, TX75070-8998, USA
³Chevron North America, Deepwater Gulf of Mexico, 1500 Louisiana, 77002 Houston, Texas, USA

Understanding along-fault flow is critical to both migration and reservoir flow modelling. However, in most cases, fluid flow is modelled only as an across-fault flow process. This paper reviews the status of research on the processes involved and the predictability of along-fault flow as well as across-fault flow in the context of hydrocarbon migration and accumulation.

The flow behaviour in fault zones depends on the following.
·   The fault zone architecture – the exact distribution of the faults and stratigraphic dips both within and adjacent to the fault zone.
·   The fault zone property architecture – the permeability, capillary, strength and mechanical properties of fault rocks and undeformed units present in and adjacent to the fault zone.

Along-fault flow as well as across-fault flow and pressure distributions are all controlled by the three-dimensional spatial distribution of the parameters listed above. The longer-term dynamic behaviour of the fault zone will depend on the stability of these properties during the geo-history.

A series of new models for assessing the importance and constraints on these parameters and predicting fault zone flow are introduced. Parameter uncertainty associated with this multi-variable system is used to conduct scenario models for: (a) the prediction of flow behaviour in complex fault zones; (b) the impact of fault zone architectures and uncertainties on modelling fault zone migration; and (c) the prediction of sealing capacities and hydrocarbon column heights.

Examples from both outcrops and sub-surface data are also used to highlight the issues required for future understanding and the improved prediction of along-fault flow.

 

AAPG Search and Discover Article #90066©2007 AAPG Hedberg Conference, The Hague, The Netherlands