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Over the past couple decades, the understanding of petrophysical parameters in bioturbated hydrocarbon reservoirs and aquifers has expanded greatly. Specifically, insights into how bioturbation impacts the distributions of porosity and permeability has occurred through both direct measurements (spot-permeameter, high-resolution imaging) and computer modelling of features such as bioturbation intensity and burrow architecture. Within this review paper, a detailed overview of the concepts associated with the application of ichnology to reservoir fluid flow from both a historical and modern perspective are completed. Following this, the nature of biogenic permeability and porosity is discussed and we inspect the ways in which burrows might influence those parameters. Focus is ultimately then applied to summarizing the most common methods used to quantify bioturbation within rock samples. The overview is then underpinned by a number of different case studies which highlight the variations of biogenic permeability encountered within a wide-ranging classification system, and we summarize those at the end. [ABSTRACT FROM AUTHOR]

Abstract: A detailed study of burrow-associated dolomites and their influence on permeability distribution was conducted on the Upper Devonian Wabamun Group in the Pine Creek gas field of central Alberta, Canada using sample imaging (micro-CT and helical-CT), spot-permeametry, and numerical modeling techniques. Spot-permeametry shows that the permeability of the lime mudstone–wackestone matrix that surrounds the dolomitized burrows is commonly below 1 millidarcy (mD). In comparison, the permeability of the burrow-associated dolomite ranges between 1 and 350 mD. As such, much of the natural gas that is stored within the matrix is produced through the higher permeable dolomitized burrows. This burrow–matrix association is referred to as Ichnofossil Hosted Tight Gas (IHG). Micro-CT and helical-CT images show that the burrows (comparable to examples of Thalassinoides and Palaeophycus) are spatially heterogeneous and their dimensions and orientations are highly variable at the centimeter scale. Horizontal burrow connectivity is more common than vertical burrow connectivity, except in the most pervasively bioturbated sections. As such, fluid flow within the burrow fabrics is anisotropic with a preferred bedding parallel flow direction. Numerical models show that the bulk reservoir permeability is influenced by the volume of bioturbation and magnitude of permeability difference between the burrows and matrix. Within dual-porosity models (contrast in permeability between the matrix and burrows is less than two orders of magnitude), bulk permeability is best estimated using the geometric mean at low to moderate volumes of burrow dolomite (25–65%) and arithmetic mean at high volumes of burrow dolomite (65–80%). Within dual-permeability models (contrast in permeability between the matrix and burrows is greater than three orders of magnitude), bulk permeability is best estimated using the geometric mean at low to moderate volumes of burrow dolomite (10–50%) and arithmetic mean at moderate to high volumes of burrow dolomite (50–80%). [Copyright &y& Elsevier]