The Halkirk posting area lies between or overlies the Killam Barrier Reef on the east and the Stettler Leduc Reef to the west. The exploration activity for the Devonian intervals was predominately during the late 1950s and early 1960s. As a result, the majority of the wells that fully penetrated the Wabamun did not run modern porosity logs. Subsequent exploration was focused on Lower Mannville gas. The majority of these wells did not drill deep enough to fully evaluate the Big Valley/Stettler. Exploration drilling has since been infrequent, while efforts have focused on exploitation. It is interesting, therefore, that 63,000 ha. of Crown P&NG rights have been posted for the May 5, 2010 land sale. The likely target of these postings becomes clear when the rights posted are compared to the regional geology of the Exshaw subcrop edge relative to the trend surface generated from the Calmar elevation. The internal structure indicates that conditions are fairly close to allowing for a subcrop trap of the Big Valley/Stettler. Since the strike is slightly open to the north-northwest and south-southeast, trapping will be difficult without additional input from hydrodynamic, stratigraphic, structural conditions or combination of the three.