Primarily used in sandstone reservoir and less in limestone areas, chemical flooding can recover around 40% of the remaining oil. The working principle of chemical injection (chemical flooding) is based on mixing certain chemicals with water and injecting this solution to the reservoir, to increase mobility of oil and reduce rock-surface tension.
Each chemical serves a different purpose and include water soluble polymers, surfactants, polymer gels, alkaline chemicals and biopolymers. Water soluble polymers increases viscosity of injected water. Surfactants and alkaline work like a "soap" and reduce surface tension (also known as IFT- Interfacial tension) and allow oil to travel more freely. Under polymer flooding, long chain polymer molecules are mixed with water and injected into the reservoir. Major objective of polymer flooding is to shut off excess water and to improve sweep efficiency, i.e. volume of the reservoir reached by the injected solution. Microbial injection is the process of affecting microbial environment in the reservoir. By injecting microbes into the reservoir, surface tension is reduced and oil viscosity and sweep efficiency is improved. This method is used very rarely, due to high costs and environmental concerns.
While done onshore, the logistics makes it easier to conduct a chemical injection EOR project. Whereas in the offshore environment it is more complex, challenging and costly, due to the fact that existing infrastructure was not designed to accommodate it, in terms of weight, space, storage and power. Retrofitting aging offshore facilities may be impossible and would require new facilities.
As an alternative, a specialized vessel can be used. However, due to the technical parameters, such a vessel must be equipped with a number of technologies that would allow desalination, treatment separation, mixing and injection of the solution. Due to the size of the vessel and technical requirements, it is cost prohibitive to build a dedicated Chemical Enhanced Oil Recovery (CEOR) vessel. Petronas in Malaysia was about to award a contract to build a first CEOPR vessel for its Angsi project, but the go-ahead was suspended.
In addition, the complex chemical processes and reactions of the reservoir are yet to be further understood and evaluated. Highly deviated wells and larger well spacing offshore makes it even more complicated.
Risks & Opportunities
- One the key challenges of successful implementation of chemical EOR projects in GCC is availability of water.
- Setting up strategic relationship with key chemical manufacturers, such as SNF Group, Tiorco, Kemira and BASF and manufacture EOR chemicals in country, would add significant value.
Supply & Demand Dynamics
While global demand of chemical injection EOR services is relatively low and has been successful on a full scale mainly is China and India, this segment has a potential to grow as high as 20% of the total EOR production worldwide. The demand will be driven mainly by onshore mature fields, with limited application in the offshore environment. GCC, North America, India, Malaysia and Latin America are major regions where chemical injection EOR projects might be pursued. Polymer Flooding is expected to constitute half of the segment, with Surfactant-Polymer and Alkaline-Surfactant-Polymer to equally share the rest.
In GCC, there have been a number of various trials conducted, including Oman, Qatar, Saudi Arabia and UAE. Key projects are:
- Marmul Polymer Flooding in Oman
- Abu Al Bukhoosh Surfactant-Polymer in UAE
- Al Shaheen in Qatar
Due to regional reservoir characteristics and conditions, Surfactant-Polymer flooding might be utilized most, as the alkaline would react counterproductive in carbonate reservoirs.
Cost & Price Analysis
EOR production is considered as a project undertaking in itself and requires a large number of equipment and packages. Studies, pilot projects, engineering design, equipment procurement, feedstock planning, drilling and other materials, play important role in EOR projects. Upfront capital costs in EOR projects are significant.
When operational, chemical injection EOR projects require a large amount of chemicals. EOR chemicals prices are very much driven by volumes shipped and costs of raw chemicals that are in high demand in other industries.