A method of heterogeneous proppant placement in a subterranean fracture is disclosed. The method comprises injecting well treatment fluid including proppant (16) and proppant-spacing filler material (18) through a wellbore (10) into the fracture (20), heterogeneously placing the proppant in the fracture in a plurality of proppant clusters or islands (22) spaced apart by the material (24), and removing the filler material (24) to form open channels (26) around the pillars (28). The filler material can be dissolvable particles, initially acting as a consolidator during placement of the proppant in the fracture, and later dissolving to leave flow channels between the proppant pillars. The well treatment fluid can include extrametrical materials to provide reinforcement and consolidation of the proppant and, additionally or alternatively, to inhibit settling of the proppant in the treatment fluid.