Ultrasonic Treatment for Removal of Asphaltene Deposits During Petroleum Production

Abstract

ABSTRACT Crude oils produced in many parts of the world contain asphaltenes. Asphaltenes are known to deposit in the vicinity of production wells during miscible floods or during thermodynamic changes. Asphaltene deposition leads to production loss and involves expensive corrective measures. This study proposes a new technique for cleaning asphaltenes with an ultrasonic device. A laboratory ultrasonic disruption device was used in this study to carry out experiments. A thin layer of asphaltene was applied to small glass beakers and the beakers were ultrasonically treated for different time periods at different amplitudes in aqueous and kerosene media, separately. Subsequent to ultrasonic treatment, the weight loss fractions were calculated. In a second series of experiments, a two inch long column of asphaltene/sand mixture was placed on top of a sand column in a flow cell, and the flow rates were measured before and after the ultrasonic treatment. The flow rates were correlated with those of sand packed columns in absence of asphaltenes. Experimental results indicated that the asphaltenes get disrupted effectively after a minimum exposure of one and a half minutes to ultrasonic radiation. However, the maximum amount of cleaning was noticed after an exposure of two minutes and at higher cycles that affect amplitude of the ultrasonic radiation. The increased flow rates meauredd after the treatment indicated that the technique can be used in an oil-field to disrupt, or desegregate asphaltenes from the vicinity of producing oil-wells. However, simultaneous pumping is recommended during the ultrasonic irradiation, to avoid the reprecipitation of the disrupted asphaltenes. The ultrasonic cleaning appears to be disrupting the maltenes that form a continuous phase to provide adhesive and ductile properties to the dispersed asphaltenes. If this technique is used, following sealed studies, in a field with a modified device, it can reduce the expenditure of taking corrective measures, and can provide technological breakthrough to petroleum industry.