Worldwide resources and reserves of unconventional hydrocarbons

Given the growing demand for energy from the billions of inhabitants in emerging countries and the inexorable depletion of the planet's reserves of conventional hydrocarbons as well as the lack of substitutes for them, unconventional hydrocarbons are increasingly making news, even more so when they are already being produced in certain countries. In fact, they account for approximately 4% of the world's current consumption of hydrocarbons. It is technically and economically feasible to tap them, but what about resources and reserves?