Description: Heat flow ( Q ) determined from bottom-hole temperatures measured in oil and gas wells in Alberta show a large scatter with values ranging from 40 to 90 mW m –2 . Only two precise measurements of heat flow were previously reported in Alberta, and were made more than half a century ago. These were made in wells located near Edmonton, Alberta, and penetrated the upper kilometre of clastic sedimentary rocks yielding heat flows values of 61 and 67 mW m –2 (Garland & Lennox). Here, we report a new precise heat flow determination from a 2363-m deep well drilled into basement granite rocks just west of Fort McMurray, Alberta (the Hunt Well). Temperature logs acquired in 2010–2011 show a significant increase in the thermal gradient in the granite due to palaeoclimatic effects. In the case of the Hunt Well, heat flow at depths 〉2200 m is beyond the influence of the glacial–interglacial surface temperatures. Thermal conductivity and temperature measurements in the Hunt Well have shown that the heat flow below 2.2 km is 51 mW m –2 (±3 mW m –2 ), thermal conductivity measured by the divided bar method under bottom of the well in situ like condition is 2.5 W m –1 K –1 , and 2.7 W m –1 K –1 in ambient conditions), and the geothermal gradient was measured as 20.4 mK m –1 . The palaeoclimatic effect causes an underestimate of heat flow derived from measurements collected at depths shallower than 2200 m, meaning other heat flow estimates calculated from basin measurements have likely been underestimated. Heat production ( A ) was calculated from spectral gamma recorded in the Hunt Well granites to a depth of 1880 m and give an average A of 3.4 and 2.9 μW m –3 for the whole depth range of granites down to 2263 m, based on both gamma and spectral logs. This high A explains the relatively high heat flow measured within the Precambrian basement intersected by the Hunt Well; the Taltson Magmatic Zone. Heat flow and related heat generation from the Hunt Well fits the heat flow–heat generation relationship determined for other provinces of the Canadian Shield. However, this relationship could not be established for Q estimates from industrial temperatures data for the study area that includes the Taltson Magmatic Zone and neighbouring Buffalo High and Buffalo Utikuma domains to the west. It appears that the spatial wavelength of heat generation change is much smaller than that of heat flow. Thermal modelling of heat flow and heat generation data from the Hunt Well, using mantle heat flow contributions of 15 ± 5 mW m –2 results in lithosphere–asthenosphere boundary depth estimates of near 200 km. This mantle heat flow value is consistent with the range for the stable continental areas, 15 (±3) mW m –2 .

Description: In order to evaluate the effects of different fluids, we measured the P and S wave speeds through a series of synthetic epoxy-bonded carbonate composites with porosities from 21.9 to 31.5 per cent and saturated with air, with kerosene and with brine. These observed speeds were converted to the saturated bulk and shear moduli and compared to predictions made using Biot and Gassmann formulations. The observed bulk moduli agreed with those calculated for both kerosene and brine saturation as did the high frequency shear modulus under kerosene saturation. The observed shear modulus under water saturation, however, was significantly lower than the prediction. After excluding the currently known mechanisms of shear weakening, we suspect this disparity may be due to variations in the wetting of the epoxy that coats the pores surfaces. The kerosene completely wets this surface while the brine is only weakly hydrophilic with a wetting angle of 73.6°. At the molecular scale, this means that Stoke's no-slip boundary condition may not always apply as has been more recently demonstrated by many researchers in other disciplines such as microfluidic engineering but the implications for wave propagation in liquid-saturated rocks have not been considered.