Heavy oils, extra-heavy oils and tar sands are major players for the

future of energy.

They represent a massive world resource, at least the size of

conventional oils. They are found all over the world but Canada and

Venezuela together account, by themselves, for more than half of

world deposits.

They share the same origin as the lighter conventional oils, but

their geological fate drove them into thick, viscous tar-like crude

oils. Most of them result from alteration processes mediated by

microbial degradation. They are characterized by a low content

of lighter cuts and a high content of impurities such as sulfur and

nitrogen compounds and metals ; so, their production is difficult and

deployment of specific processes is required in order to enhance

their transportability and to upgrade them into valuable products

meeting market needs, and honouring environmental requirements.

Although these resources are increasingly becoming commercially

producible, less than 1 % of total heavy crude oil deposits worldwide

are under active development.

The voluntarily wide scope of this volume encompasses geology,

production, transportation, upgrading, economics and environmental

issues of heavy oils. It does not pretend to be exhaustive, but to

provide an authoritative view of this very important energy resource.

Besides presenting the current status of knowledge and technology

involved in exploiting heavy oils, the purpose is to provide an insight

into technical, economic and environmental challenges that should

be taken up in order to increase the efficiency of production and

processing, and finally to give a prospective view of the emerging

technologies which will contribute to releasing the immense potential

reserves of heavy oil and tar deposits.

This book will consequently be of interest to both specialists and

non-specialists who are looking for a general overview on the

question of heavy crude oils.