Properties of Utah tar sands--South Seep Ridge area, P. R. Spring deposit

The Bureau of Mines analyzed three cores from the south Seep Ridge area of the P. R. Spring tar sand deposit of northeastern Utah. Four tar sand zones are indicated in the area. The zones range in average thickness from 13 to 24 ft. The total net thickness of the tar sand in the three coreholes ranges from 71 to 112 ft. The tar sand occurs between the depths of 27 and 54 ft. It has good porosity, 25.6 pet of bulk volume; high permeability before and after oil extraction, 819 and 2,218 md, respectively; but a relatively low oil saturation, 36.5 pet of pore volume. Gravity of the oil ranges from 8.2° to 16.5° API.