Method of removing tar sands from subterranean formations

Abstract

Hydraulic mining of tar sands in a formation wherein water is introduced into a plurality of spaced cavities in the bottom of a tar sands formation and above a number of tunnels communicating with respective cavities by openings. In one embodiment of the method, water is sprayed onto exposed tar sands surfaces in the cavity and further creates a moist atmosphere in those regions of the cavity where the water is not directly sprayed on the surfaces. The moist atmosphere can be in the form of suspended water droplets or can be saturated water vapor at a temperature above the ambient temperature of the tar sands or a combination of both. The water on the exposed surfaces penetrates the formation along paths of preferential wetability, causing adjacent portions of the formation to separate and break loose from the formation itself in a direction in which the portions are free to expand. This separation enlarges each cavity and the separated tar sands portions eventually disintegrate and become loosened tar sands by the continued presence of the water spray and the moist atmosphere. Heat can be introduced in the form of steam or by heating the incoming water, and the heat accelerates the separation of the formation and the disintegration of the tar sands portions. The disintegrated tar sands are slurried in water with the aid of one or more water jets or by other suitable mechanical action, and are removed as a slurry by gravity flow from each cavity.