Enhanced oil recovery (EOR)
Interfacial technology for efficient oil field exploitation
The discovery of huge new stocks of crude oil is becoming less and less frequent, and is accompanied by ever increasing cost. Accordingly, the interest in increasing the yield of the existing crude oil reservoirs is growing. Unfortunately, the majority of all the oil inside the reservoir is trapped in the reservoir’s porous media. To exploit this oil, there is the need for methods of enhanced (or tertiary) oil recovery. Our surface and interfacial science instruments help to make these methods more efficient and thereby less expensive.
In the so-called chemical flooding method, a surfactant solution is pumped into a reservoir to wash off the oil from the walls and to form an oil-surfactant (micro) emulsion that can be easily transported to the surface. For this, the interfacial tensions between oil and surfactant solution should be in a range well below 1 mN/m.
Measuring interfacial tensions down to 10-6 mN/m is the playground of our Spinning Drop Tensiometer – SDT. The results provide information to help modify the surfactant solutions in order to adjust the interfacial tension for every specific oil field. The instrument also monitors the temperature dependence of the interfacial tension, which is important considering the expected large temperature differences between the oil-reservoir and the earth’s surface.
For approaching the characteristics of surfactants used in enhanced oil recovery, more common surface tension measuring techniques, like the Wilhelmy Plate method, are used. A fully completive and automatic determination of the critical micelle concentration (CMC) serves to describe the efficiency of a surfactant.
For further development of oil exploitation techniques, investigating surfaces and their wetting behavior under thermal and pressure conditions of the reservoir is a prerequisite. Appropriate interfacial tension measurements with the pendant drop method can be carried out with our high pressure unit.
Contact angle measurements with the same unit provide information about wetting and adhesion behavior between crude oil and stone.
As the amount of liquid required strongly decreases when transporting the oil with foam, high pressure foam analysis can be used to support this method of enhanced oil recovery.
AR276: Interfacial rheological measurements on crude oil emulsions
During oil production, oil/water-emulsions occur. These are broken using demulsifiers in order to reduce corrosion as well as the viscosity when pumping. Interfacial rheological analyses on asphaltenes show how the quality of demulsifiers can be predicted based on the storage modulus E’. The results for different demulsifiers correlated with their efficiency in dewatering and pumping energy tests.
AR273: Ultralow interfacial tension in enhanced oil recovery (EOR)
Chemical flooding, an enhanced oil recovery method, requires a very low interfacial tension between oil and water. In the ideal case, this leads to the formation of a micro-emulsion which mobilizes the oil adhering in the reservoir to the best possible extension.
AR227: Phase boundaries under pressure
A high pressure cell is used to investigate the dependency of interfacial tension between oil and water and their respective densities on pressure applied up to 300 bars (ca. 4000 Psi).