Abstract
Nano-particles have been investigated in the last few years as a promising technique for enhanced oil recovery at laboratory scale. Different metal oxides nano-particles have been tested solely in previous papers and some of these nano-particles increased the ultimate oil recovery.
This paper investigates the effect of mixing more than one nano-oxide in one dispersing fluid (to form a nano-fluid) on the ultimate recovery. Three nano-oxides were selected: Aluminum oxide (Al2O3), Iron oxide (Fe2O3) and Silicon oxide (SiO2). The selection of these oxides was based on the percentages of additional recovery each nano-oxide provided in literature and the mechanism that caused this increase in recovery. Each oxide is believed to increase recovery through different mechanism and combining different oxides with different recovery enhancement mechanisms may lead to further increase in ultimate recovery.
Three reference core flooding runs were performed in order to check the effect of each nano-oxide on the experimental core plugs ultimate recovery after water flooding. Different single nano-fluids were injected in each core until no more oil was produced. The same mixture of nano-fluids was then injected in the three cores resulting in more oil production in all cases (thus validating our concept).
To understand the different effects these nano-fluids may have on recovery, several experiments were conducted. These tests included three experimental runs with different mixture concentrations of nano-particles on a high permeability core starting directly with tertiary recovery (no water flood was applied before injecting the nano mixture).
The outcomes of these experiments showed that nano-fluid mixtures could be used as a better technique for EOR than single nano-fluid. Optimum nano-fluid mixture cocentration depends on both fluid and rock properties. The use of different slugs with different nano-fluids seems to benefit the recovery.
