Column heights in faulted traps are thought to be controlled by juxtaposition of reservoirs against top seals and/or capillary effects of the fault-rocks themselves. In binary sand/shale sequences, fault rocks are often composed of discrete shale smears, quantified by the shale smear factor (SSF). Field observations supplemented by sandbox experiments show that smears tend to be continuous in cross-section from footwall to hanging wall at low values of SSF but become breached (forming holes) as displacement increases. The critical value of SSF at which breaching occurs depends on the strength/brittleness of the clay/shale layer and the confining stress at which fault displacement occurs. In this case the distribution of smears and holes may directly control column height in a way analogous to juxtaposition. However, the location of holes is not predictable and we address this variation using the probabilistic shale smear factor (PSSF). Convolution of stratigraphy with shale smear architecture introduces a spectrum of complexity. For multiple beds and probabilistic smear breaching, holes are more likely at lower SGR. However, these holes may themselves have limited seal capacity due to cataclasis and/or cementation.


Article metrics loading...

Loading full text...

Full text loading...


  1. Childs, C., Watterson, J. & Walsh, J.J
    . [1997] Complexity in fault zone structure and implications for fault seal prediction. in: Møller-Pedersen, P. & Koestler, A.G. (eds), Hydrocarbon Seals: Importance for Exploration and Production, Norwegian Petroleum Society (NPF) Special Publication 7, 61–72, Elsevier, Singapore.
    [Google Scholar]
  2. Freeman, B., Yielding, G., Needham, D.T. & Badley, M.E.
    , [1998] Fault seal prediction: the gouge ratio method. In: Coward, M.P., Daltaban, T.S. & Johnson, H. (eds), Structural Geology in Reservoir Characterization. Geol. Soc. Spec. Publ. 127, 19–25.
    [Google Scholar]
  3. ManzocchiT., ChildsC. & WalshJ. J
    . [2010] Faults and fault properties in hydrocarbon flow models. Geofluids, 10, 94–113.
    [Google Scholar]
  4. Schmatz, J., Vrolijk, P.J. & Urai, J.L
    . [2010] Clay smear in normal fault zones – The effect of multilayers and clay cementation in water-saturated model experiments. Journal of Structural Geology, 32, 1834–1849.
    [Google Scholar]
  5. Vrolijk, P., Urai, J.L., Kettermann, M.
    [2015] Clay Smear: Review of Mechanisms and Applications, Journal of Structural Geology, doi: 10.1016/j.jsg.2015.09.006.
    https://doi.org/10.1016/j.jsg.2015.09.006 [Google Scholar]
  6. Yielding, G., Freeman, B. & Needham, T
    . [1997] Quantitative Fault Seal Prediction. AAPG Bulletin, 81, 897–917.
    [Google Scholar]
  7. YieldingG., BretanP. & FreemanB.
    [2010] Fault seal calibration: a brief review. From: Jolley, S. J., Fisher, Q. J., Ainsworth, R. B., Vrolijk, P. J. & Delisle, S. (eds) Reservoir Compartmentalization. Geological Society, London, Special Publications, 347, 243–255.
    [Google Scholar]

Data & Media loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error