Emulsion Design Tool

Lecture Notes

The figure at the top of this slide is an example permeability distribution for a cross-section through the simulation area.

The darker red areas are higher permeability zones, while the lighter pink areas are low K zones.

This permeability distribution was generated using a statistical procedure based on measured permeability distributions at a number of different sites.

Emulsified oil is injected into this hypothetical aquifer through the two wells identified at the bottom.

The bottom figure shows the simulated oil distribution using a mass and volume scaling factor of 0.78.

This means that the total mass of oil injected is equal to 78% of the maximum oil retention in the treatment zone, and

the total volume of oil and water injected is equal to 78% of the pore space in the treatment zone.

In the middle of the simulation grid between the two injection wells, there is a mixture of contacted and uncontacted zones.

The oil contacted zones are high permeability layers where the oil is rapidly transported.

The uncontacted zones are typically lower permeability regions.

While the oil distribution shown above is not perfect, it should still result in fairly rapid biodegradation and should be very effective in preventing downgradient migration of dissolved contaminants.

In the oil contacted zones, the oil will ferment to hydrogen and acetate resulting in the most rapid biodegradation.

Hydrogen and acetate produced in the oil contacted zones will also diffuse into the uncontacted zones, stimulating biodegradation. However, biodegradation rates will probably be lower in the uncontacted areas because of the lower electron donor concentrations.

Over time, contaminants will also diffuse out of the lower K zones, coming in contact with oil.

Since the high K zones are effectively contacted and the high K zones also transmit the most contaminants, the oil distribution shown in this slide should be very effective in controlling the downgradient flux of dissolved contaminants.

In later slides, we show the effect of varying the amount of water and oil injected on contact efficiency.

Volume contact efficiency is calculated for the region between the two injection wells.

You need to be aware that contact efficiency is NOT the same as treatment efficiency, since contaminants can be degraded by dissolved hydrogen and acetate released from entrapped oil.

That said, higher contact efficiency can generally be expected to result in higher treatment efficiency.