I tried to make emulsion of 1000ppm crude oil in normal water and it works. However, when I used the same formula in 3.5% NaCl, the oil was separated from the solution in just a few hours.

Formula I used:

1L of water (or 3.5% NaCl)

0.9 g of crude oil

0.1 g of SDS

I only have SDS for now. Should I try to use higher amount of SDS, maybe 1:1 to crude oik? or 0.5:1?