Using the services mentioned earlier ELS provides fully integrated chemical design. This can be dependent on injection and formation water properties, crude and reservoir properties. But also the operators capability, facilities and commercial/tax regime is taken into account. In the end the choice for an EOR design is a commercial/economic one. ELS, Azuren and PanTerra are there to provide all the input to a quality and informed decision.
Chemical EOR is the optimization of injection water by adding a chemical or fine-tuning the chemistry. There are four types of chemical EOR:
- Polymer flooding where the injection-water is made more viscous in order to push the crude from the injection- to the producing well. This type of EOR is mostly used with crude that have a higher viscosity
- Surfactant flooding where a “soap” is pushed through the reservoir to get remaining oil droplets out of the pores by reducing the surface tension of the droplets. This creates a micro-emulsion which increases the mobility of the crude. The soap can be the surfactant or created as petroleum soap by alkali. The chemical cocktail is stabilized by polymer hence the name Alkali Surfactant Polymer (ASP) flooding.
- Surfactant Polymer (SP) flooding is where no alkali is used. This is applicable in reservoirs with more saline formation water. Alkali and saline water produces scale and will clog up the producing wells.
- Low Salinity flooding where a reservoir with higher salinity formation water is flooded by fresh water. The fresh water releases the clay bound oil droplets in the reservoir.