Electro-deposition of asphaltenes from Abu Dhabi crude oil/synthetic formation water mixtures

In this work, asphaltenes precipitation and deposition induced by applying an electric field to Abu Dhabi crude oil sample were studied. The asphaltic particle electrical charge and asphaltic deposits mass at different operating conditions were determined. Direct current (DC) was applied between two graphite electrodes dipped in crude oil/synthetic formation water mixture of 240K ppm salinity. Three current densities of 10, 20, and 30 A/m² were applied. Deposits were collected on the electrodes surfaces and their mass was recorded using low capacity load cells (up to 50g). Anodic and cathodic deposits were observed at different operating conditions. The results revealed that asphaltic nature deposits were detected on the anode. The mass of deposits on the electrodes increased with experiment time and current density. With higher current density at experiment times below 10 hrs, the rate of the mass increase was faster. No charge alterations noticed with increasing run time and current density. Experiments showed that the maximum amount of asphaltic material arrested on the anode was 18% of the original asphaltic material in crude oil sample for current density of 30 A/m² and 24 hours run time. Eventually, an asphaltene preventive/minimizing criterion can be set to combat deposition during production and enhanced oil recovery processes.