The control of asphaltene precipitation in oil wells

Asphaltene instability can occur in petroleum reservoirs leading to permeability reduction and deposition in transportation pipes restricting fluid flow. In this work, effect of reservoir pressure on amount of asphaltene precipitation was investigated. Two different asphaltene inhibitors (a new developed and an industrial) were used for preventing asphaltene deposition under static and dynamic conditions. Viscosity measurements of the oil, core flooding experiments and transmittance measurement were conducted to understand asphaltene precipitation and deposition behavior as well inhibitor efficiencies. Optimum concentration of the new asphaltene inhibitor was 200ppm. Experiments show inhabitation efficiency of new inhibitor can reach up to 90% and showed better performance when compared with industrial one. In addition, squeeze lifetime of new inhibitor was 1.86times longer than the industrial inhibitor in carbonate core samples. In the presence of new inhibitor formation damage and percent of transmittance was lower than in the presence of industrial asphaltene inhibitor.