Reservoir damage occurs from the moment fluids are injected into reservoirs. Different types of drilling and completion fluids invading the formation can cause a change in wettability, destabilise clays, cause emulsions and introduce fines into the formation which bridge across pore throats. The presence of any or all types of reservoir damage can have a serious cumulative effect on production.
Surfactants are chemicals containing water and oil soluble groups (hydrophilic and hydrophobic) and primarily reduce the interfacial tensions between two fluids, a fluid and a gas, or a fluid and a mineral surface. Depending on the ionic charge of the water-soluble group, surfactants have a wide variety of applications. They are an essential part of drilling, cementing, completion, and stimulation fluids, and are used to treat any or a combination of the aforementioned reservoir damage. Furthermore, surfactants are commonly used in treating tight gas wells, in scale removal treatments, and even in enhanced oil recovery programmes.