Essentials of Polymer Flooding Technique

Chapter one Why Enhanced Oil Recovery?

In this chapter, the different production stages of an oil‐bearing formation will be discussed with the goal of introducing enhanced oil recovery (EOR) techniques. Mainly, this chapter will discuss the common terminology used in the industry – which divides the life cycle of an asset into three stages (primary, secondary, and tertiary production) – to show the benefits of starting EOR techniques earlier in the development phase.

1.1. What Is a Reservoir?

The reservoir is an important component of a petroleum system. Oil and gas are formed from the decomposition of organic matter at high temperature and pressure in a source rock. Once formed, they can migrate upward until they either reach the surface and are degraded or are trapped by a seal or cap rock. If trapped, they tend to accumulate within a formation called a reservoir (Figure 1.1). Wells are drilled to reach this formation and start the extraction of the fluids.

Figure 1.1 Petroleum system and oil‐bearing reservoirs.

A reservoir can be defined as subsurface rock formation having sufficient porosity and permeability to store and transmit fluids. Sedimentary rocks are the main formations of interest since they usually have higher porosity than magmatic and metamorphic ...