The energy spectrum of the world has changed dramatically over the last 100 years. Production and utilization of oil, the many offshoot industries it has spawned, and the technological advances developed have literally transformed the world as we see it today. The ubiquitous perception of abundant energy is also slowly changing, as the internet has brought information regarding the geopolitics of energy front and center.

However, have you ever asked people around you – your family, your friends, people at the fitness center – what percentage of oil can be extracted from a reservoir on average? Or, better yet, have you ever discussed with them their understanding of a geologic reservoir? You would probably be surprised to learn how many people think hydrocarbons can be recovered using a straw planted in a big, dark cavern full of oil or gas, or by shooting a bullet into the ground and having “black gold” bubble out. Moving from this fiction to reality requires education, science, time, and observation.

Moving hydrocarbons requires energy. The fossil fuels the world consumes on a daily basis are trapped in a porous material: an ancient, solid sponge formed by the accumulation of sediments over millions of years. What happens if you try to draw water from a sponge with a straw? It it slightly more difficult than simply pulling bulk fluid from a container. This same concept extends to hydrocarbon extraction.

Of the many available methods to produce hydrocarbon reserves, one involves water injection to sweep the oil toward producing wells. While widely deployed, this process (waterflooding) only helps recover approximately 35% of the oil contained in the giant “sponges.”

35%! Really? That's not much.

With 65% of the resource stranded in place, engineers and scientists have worked for decades to develop technical solutions to recover it. Enhanced oil recovery (EOR) technologies have been implemented in various fields around the world, always using a case‐by‐case approach. One such technique consists of injecting viscosified water into the formation to displace the oil, instead of regular water. The viscosity contrast between the injected water and the viscous oil creates instability and promotes water penetration through the oil or complete bypass of the oil via geological highways (i.e. where the sponge or reservoir has the largest connected pores, making the flow much more easily). Increasing the viscosity of the water through the addition of water‐soluble macromolecules (polymers) helps homogenize the displacement in the geologic formation: a larger volume of the sponge is contacted at the same time, leading to more efficient displacement and more oil being produced. This technique is called polymer flooding. It has been implemented since the late 1960s, with large commercial and technical success.

This book aims to summarize the key factors associated with polymers and polymer flooding – from the selection of the type of polymer through characterization techniques, to field design and implementation – discussing the main issues to consider when deploying this technology.

In an attempt to keep things simple, what follows is a pragmatic, rather than exhaustive, review of polymer flooding.

In terms of vocabulary, this is the last time you will read the word sponge; however, it is not the last time you will read the word viscosity!