Porosity and Permeability in Bioturbated Sediments - Trace Fossils as Indicators of Sedimentary Environments - page 818

In many instances, spot-permeametry testing is undertaken using a Pressure-
Decay Profile Permeameter. Lab bench devices measure the permeability of gas
in the range from 0.001 mD to

30 D through a probe tip (e.g., Knaust, 2009;
Lemiski et al., 2011; Pemberton and Gingras, 2005; Tonkin et al., 2010 ).
Permeability is normally measured using a grid pattern on slabbed and cleaned
cores or rock faces. Good practice is to collect five measurements from each
point on the grid, with the maximum and minimum values for each spot being
discarded, and the remaining three values averaged ( La Croix, 2010; Lemiski
et al., 2011 ; Fig. 5 ). Anomalous measurements can result from poor probe-
tip seals and should be removed from the dataset altogether. The averaged
permeability values can then be plotted and contoured to produce plots of
the permeability fields.

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4.2 Trace-Fossil Architecture and Distributions
4.2.1 Outcrop and Core Data
Spatial data is commonly interpreted from two-dimensional data sets such as
core and outcrop data. Observations that can be made pertaining to the biotur-
bate texture are limited by the size and quality of the rock exposure or sample
available. The sample size is very important, as permeability fabrics must be
upscaled. Unfortunately, outcrops seldom provide a three-dimensional under-
standing of their structure, but the spatial distribution of burrow fabrics may
be displayed. Because it commonly samples the reservoir, core is a good source
of permeability data; however, the representative elemental volume is small.

FIGURE 5 An example of contoured spot-permeameter data from the Alderson Member, Milk
River Formation, Cretaceous of Alberta (Canada). This example is dominated by Phycosiphon and
shows a range of permeability variance from < 1to > 24 mD.