Most of the growth in supply from today’s recoverable gas resources is found in unconventional formations, made accessible by innovative technologies including horizontal drilling and hydraulic fracturing.
Conventional crude oil flows relatively easily through a well or pipeline.
Heavy oil is a more dense, viscous oil, with a high proportion of bitumen, that is difficult to extract with conventional techniques.
Oil sands are a thick mixture of bitumen, water, sand, heavy metals and clay.
Tight oil, trapped in formations of low porosity and permeability (like shale), requires horizontal drilling and stimulation such as hydraulic fracturing.