Primarily used in the 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 the 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 increase viscosity of injected water. Surfactants and alkaline work like a "soap" and reduce surface tension (also known as IFT- Interfacial tension) and allow the oil to travel more freely. Under polymer flooding, long-chain polymer molecules are mixed with water and injected into the reservoir. The 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 the 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 make 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.
Enhanced Oil Recovery (EOR) is a set of activities and techniques designed to reduce oil saturation and increase the oil recovery rate. In general, oil production is divided into 3 stages: primary, secondary and tertiary (improved). The tertiary method is also called Enhanced Oil Recovery (EOR).
EOR is used when the primary (natural flow) and secondary (water and gas injection) methods are no longer effective and normally leave around 60-80% of oil unrecovered. Using EOR can help to recover more oil, and help to achieve higher recovery rates. For gas wells, the primary production method is normally enough to produce around 80% of the reserves. Hence, EOR is used in crude oil production.
EOR techniques are very costly and the price of oil is a key factor for an operator when decisions are made on what EOR technique to implement. What could be technically feasible might be expensive and not economical. In addition, there is always a dilemma between exploration (to find more oil) and EOR, and sometimes exploration risks are too high, thus companies choose EOR approach instead. In addition, the pace of new oil discoveries and its size has been declining; hence producing more oil from existing fields is a dominant thinking for a few years to come.
Screening criteria on of which EOR method to deploy require a detailed analysis of a particular field and its location, reasons of lower recovery rate following primary and secondary methods, is conducted to understand the strategy and what EOR approach to apply. Due to a number of reasons, both technical and commercial, EOR makes economic sense in larger fields.
Offshore EOR makes it even more challenging and costly, due to the fact that existing infrastructure was not designed to accommodate equipment packages associated with it in terms of weight, space, treatment facilities and power generation. In addition, due to well-placement offshore and the distance between the wells, any EOR campaign will require more time to have a noticeable effect. On average an EOR project takes 1-7 years till it is fully deployed. Laboratory testing and pilot projects are prerequisites of any full-scale EOR development and can take up to 4 years to complete.
EOR is divided into 4 distinctive categories as shown below.
Each EOR technique has its own use in and it is hard to be definitive with any particular EOR technique, as every method unique enough to work better in some cases than the others. Below are a guide and major characteristics of available EOR methods.
Worldwide, EOR contributes to around 3MM B/D of production, which is less than 5% of global crude production. Thermal injection is the largest and most widely used EOR method.
After long years of production, the recovery rate in most of the fields in the GCC is coming to a point, whereby focusing on EOR considerations become more and more important - most oil fields in the region have been under primary and secondary production for decades. Although the fields do not require any EOR yet, some of the EOR projects in the GCC are one of the world's biggest and challenging, whereby the most advanced technology is used. Those include steam injection and polymer flooding in Oman, gas injection in UAE and CO2 pilot projects in UAE, Saudi Arabia, and Qatar, with more steam injection projects on the way in Kuwait. Oman is the regional leader in EOR projects and has implemented thermal, chemical and gas injections projects. It is estimated that by 2020, EOR production in Oman will be around 22% (PDO).
As a result of growing population and efforts to maintain and increase oil production in the GCC, it is becoming more challenging to meet the demand for natural gas to cater to power generation, gas re-injection projects and steam generation. Hence, focus on other EOR methods, such as chemical and CO2, will be evident in the years to come.
CO2 EOR projects are gaining more traction, not only because of its favorable economics but also as part of sustainable practices, as well as preserving natural gas used for gas injection, for power generation purposes and alike. There have been a number of research centers established in UAE, Qatar and Saudi Arabia to make progress in applying CO2 EOR in the region. NOCs in the region are taking proactive steps to establish a knowledge base and expertise ahead of time.
EOR is challenging and time-consuming and ineffective screening may result in lower-than-expected recovery rates. It is a common practice to conduct small trial projects to understand which EOR technique delivers the best project economics. In addition, the environmental impact and effects of chemicals could be best understood in smaller projects.
Some of the giant fields in GCC will not require EOR for the next 20-30 years. However, certain fields may need one in the next 3-5 years. The chart below represents the projected growth in EOR production worldwide. Growth in EOR production in GCC is evident and represents a notable proportion of GCC oil production.
Risks & Opportunities
Risks & Opportunities
- One the key challenges of the successful implementation of chemical EOR projects in GCC is the availability of water.
- Setting up strategic relationships 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
Supply & Demand Dynamics
While the global demand for chemical injection EOR services is relatively low and has been successful on a full scale mainly is China and India, this segment has the 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 counterproductively in carbonate reservoirs.
Cost & Price Analysis
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 an important role in EOR projects. Upfront capital costs in EOR projects are significant.
When operational, chemical injection EOR projects require a large number of chemicals. EOR chemical prices are very much driven by volumes shipped and the costs of raw chemicals that are in high demand in other industries.
Almost every EOR project is bespoke and requires a large number of studies, pilot projects, and simulation. As a result of this, equipment and packages are not standard and may require bespoke engineering and manufacturing every time, which in turn reduces the diversity of available suppliers, increases costs and lead times.
The most critical levers that would influence the costs and procurement decisions are
- A comprehensive FEED study
- Analysis of the supplier market and their capabilities.
While there are numerous engineering companies providing the services of FEED studies, companies who specialize in the EOR studies and consultancies are in a better position to produce a more valuable and meaningful FEED - as they have large exposure to varus EOR projects.