A Dutch researcher has designed a simulation program to study the interactions between oil and water outside of the laboratory, research which will help provide insight into the behavior of contaminated ground water.

How do oil and water really respond to each other? Up until now, researchers could only study that in the lab. However, Dutch researcher Twan Gielen has designed a simulation program to study the interactions between oil and water outside of the laboratory. This research, funded by the Netherlands Organization for Scientific Research, provides insight into the behavior of contaminated ground water.

Scientists want to know how oil and water behave in the ground. The formula that currently describes this behavior comes from the laboratory, and assumes that oil and water are in balance. In this case, only the saturation of fluids plays a role. However, in practice, several factors play a role – for example, the time and location of the fluids. Gielen has developed a model to simulate the reality at a micro-scale level.

Gielen’s model resembles a tower of small marbles. These hollow marbles have a diameter of about 0.004 inches. The marbles represent the pore space between sand grains, and the large cavities link the small pores together. The tower is 30 marbles wide, 30 marbles deep and 40 marbles high – the maximum number on which the computers can perform calculations. Gielen's simulations presented a good picture of the distribution of the oil and water flows in the pore space.

The key phenomenon in two-phase fluid dynamics research is the differential pressure between oil and water – capillary pressure. If you can calculate this pressure, you can determine how oil and water move with respect to each other. Gielen used his data to extend the traditional description of capillary pressure. With this description, he could more realistically describe the behavior of the two fluids, and he was the first person to follow this behavior over the course of time at this scale. In the future, researchers want to use the model to make precise calculations about the movement of ground water contamination.