Measurement and evaluation of the effect of filtration and dissolved gases on the wax appearance temperature of waxy oil under the reservoir condition with high-pressure microscopy

The effect of filtration and dissolved gases on the wax appearance temperature (WAT) of oil samples from reservoirs in Kharyaga was investigated in this research. In live oil samples compared to dead oils, a decrease in temperature of about 5 degrees was observed in WAT, and as a result, it can be said that wax in oil containing dissolved gases at a lower temperature than the same oil sample without dissolved gas has begun to form. In other tests, filtered oil samples were compared with unfiltered ones. Contrary to expectations, in filtered samples (both live oil samples and dead oil samples), wax began to form at higher temperatures. The oil samples were filtered in two steps; the first filtration with a mesh size of 40 microns and the second step with 2 microns mesh size. To solve the problem that wax appearance temperature (WAT) acquired by conventional method is not suitable and effective to the subsurface live crude oil and dark oil, a way to measure the WAT of crude oil varying in properties is explored using the high-pressure microscopy. In WAT measurement with HPM, as the temperature of crude dropped, solid wax crystallized from the crude, by continuing the temperature drop and measuring the percentage of particles in the sample images by the device, the WAT point was obtained.