The breadth and coverage of analytical expertise in the IEA Technology Collaboration Programmes (TCPs) are unique assets that underpin IEA efforts to support innovation for energy security, economic growth and environmental protection. The 38 TCPs operating today involve about 6 000 experts from government, industry and research organisations in more than 50 countries1.
Enhanced Oil Recovery (EOR TCP)
Increasing oil production from mature reservoirs
The EOR TCP supports national efforts to reduce costs of existing technologies and to research new technologies to enhance reservoir oil recovery. Between 30% to 70% more oil could be recovered from mature oil reservoirs through the use of enhanced oil recovery technologies such as polymer injection, or “flooding”.
Crude oil is expected to supply 26% of the world’s energy until 2040.** Given that the average recovery factor per oil reservoir is only 20% to 40% and that the majority of oil reservoirs are mature, improving the amount of oil extracted in existing reservoirs is a priority. For these reasons the EOR TCP organises symposia to assess state-of-the art applications for oil exploitation: reservoir characterisation and injection of gases or liquids to increase the amount of oil recovered.
The challenge of oil production is to maintain sufficient pressure within the reservoir to push the oil upwards. This is facilitated by injecting a gas such as CO2, steam or a liquid into the reservoir. Water may be effective for oils that are lighter in density, but it only results in a 10% extraction rate for reservoirs containing heavier oils.
The focus of one ongoing activity of the EOR TCP is to examine the addition of chemical compounds (surfactants and/or polymers) to the water to facilitate movement of the oil within the reservoir and resulting increase in oil extraction. Surfactants lower the surface tension between the water and the oil while polymers with a higher viscosity than water push the oil through the reservoir.
Injection of surfactants and/or polymers has been shown to increase oil recovery by a further 5% to 20%, a considerable benefit, particularly for fields with dense or heavy oils. Yet some challenges remain, particularly for polymers. Obtaining the appropriate viscosity based on the quality of the oil, adhesion to the reservoir rocks, and the plugging of injection wells are some of the key challenges.
For these reasons polymer flooding has been relatively limited to date except in China where a recent policy required that oil companies make all efforts to maximise recovery rates. Following an earlier symposium in China, and further benefiting from the experience exchanged with experts in China, four participants of the EOR TCP aimed to reduce the uncertainty and risk of polymer flooding through a pilot test of the technology.
In Austria, polymer flooding was tested in a mature oil reservoir (8th Reservoir, Matzen Field) where the share of oil produced was on the decline. After injecting the polymer, more oil was produced, demonstrating enhanced mobility of the oil. The additional oil recovered was found to be a result of acceleration (30%) and improved oil mobility (70%).
In addition, through the use of tracer tests and laboratory experiments, polymer adherence to the reservoir rock could be simulated. The simulations were consistent with the results obtained in the reservoir – incremental amounts of oil were recovered and the amount of polymer required could be quantified.
These and other findings are described in the report, User Tracer Data to Determine Polymer Flooding Effects in a Heterogeneous Reservoir.
- Development of gas flooding techniques
- Dynamic reservoir characterisation
- Fluids and interfaces in porous media
- Surfactants and polymers
- Thermal recovery
For more information: http://iea-eor.ptrc.ca/
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