Comparing depositional environments and porous zones in the 400 million-year-old sabkhas of subsurface Alberta

Abstract

Using subsurface core and well logs, a comparison of sedimentary deposits in evaporite-containing formations of the Devonian hypersaline seas of Alberta was done. Thin sections from the Nisku Formation were examined using a petrographic microscope to determine how and when brine and hydrocarbons moved through two porous zones, identified by well logs from the same area. These two zones within core and thin sections were compared with other zones from which only well logs were available. Through measurements of the porosity, permeability, and timing of diagenesis from petrography, it is determined that areas of high neutron and density log responses correlate with cemented zones within the core. This research has a direct impact on the understanding of how evaporitic facies can cause different responses within well logs. Our understanding of how well logs, accompanied by core and thin section analysis, can give insight into the movement of fluids and gases in subsurface Alberta is also aided.

* Indicates faculty mentor.