Three-Dimensional Morphological and Permeability Modelling of Diplocraterion

ABSTRACT

Three-dimensional mini-permeametry of Diplocraterion burrows from the Middle Jurassic Scarborough Formation of North Yorkshire, UK, reveals some of the relationships between ichnofossils and reservoir quality in conventional siliciclastic petroleum reservoir facies. This work focuses on the effect that the various Diplocraterion burrowing behaviours have on the permeability characteristics of the near-burrow environment. Samples were studied using serial grinding and mini-permeametry. This is the first documented attempt at combining these techniques to create an integrated understanding of the inter relationship of trace fossil morphology and reservoir quality in three dimensions. Palaeobiological insights arising from the three-dimensional modelling include evidence for resuspension feeding, deposit feeding, sediment cleaning and “collapse-cone feeding.” Higher than expected permeability values (>150 mD) were measured from the sandy shafts of Diplocraterion and adjacent areas. Zones of enhanced permeability associated with the inter-shaft area are inferred to result from sediment cleaning, and grain-size selective deposit feeding. Bioturbation by Diplocraterion is found to improve reservoir quality by sediment cleaning and creation of highly permeable vertical conduits in a reservoir facies with otherwise low permeability.

KEYWORDS:

• Diplocraterion
• Three-Dimensions
• Permeability
• Modelling
• Morphology
• Ichnology

Acknowledgments

Mary Leaman thanks Liam G. Herringshaw and Nikki Tonkin for their initial support at the beginning of the project; Liam G. Herringshaw, Michael Garton, and Chris Boyd for their assistance in the field; Chris Boyd for sample preparation and serial grinding; Małgorzata (Czarrna) Bednarz for three-dimensional modeling; and Colin Brisco for some data collection. This manuscript was improved by the reviews of Andrew Rindsberg and Evan Edinger.

Funding

This work is supported by Petroleum Research Atlantic Canada (PRAC) and a Natural Sciences and Engineering Research Council of Canada (NSERC) grant to DMc.