Evaluation of Eco Friendly Bio-Oil Dispersants on the Inhibition of Asphaltene Precipitation in a Kuwaiti Crude Oil

Abstract

Abstract Asphaltene precipitation, flocculation and deposition are vital problems that may cause serious damage to reservoirs, wells, and production facilities. Asphaltene precipitation may occur during primary depletion or acidizing jobs as well as after the injection of rich gas or carbon dioxide. The Organic deposition removal is considered a costly workover job with the current oil prices. The solvents that are usually used are toluene and xylene, which are considered carcinogenic and toxic chemicals. The use of dispersion to inhibit the organic deposition is essential and can be expensive, as it is required for the life of the well. The objective of this paper is to compare the effectiveness of two chemical dispersants and deasphalted oil against vegetable oils (coconut oil and andiroba oil) on the inhibition of asphaltene precipitation. A Kuwaiti crude oil sample was used in this study with an API of approximately 38° and asphaltene content of 2 wt%. The crude oil was characterized by a variety of analytical techniques including: Total acid number (TAN), Total base number (TBN), water content, Saturates, Aromatic, Resins, and Asphaltene analysis (SARA), density, viscosity and elemental analysis. Dispersants and vegetable oils were analyzed by Fourier Transform Infrared spectroscopy (FTIR) to determine the functional groups. An Asphaltene dispersants test was carried out at different concentrations of 150, 300 and 500 ppm and temperatures of 25 and 70°C to evaluate the dispersant efficiency and limitations. The results of this study showed that the dispersant should be designed based on understanding the asphaltene structure and interaction mechanism. Temperature greatly affects the blended dispersant performance due to the relation of asphaltene solubility and temperature; therefore designing optimum concentration must be taking into account. Employing the deasphalted oil as solvent to mitigate asphaltene precipitation can be desirable from economical perspective. Coconut oil performs very well as an asphaltene dispersant when paired with DAO at a concentration of 500 ppm or solely at 25°C. The results can be employed in designing and optimizing dispersants that are environmental friendly and cost effective.