A Review of Oil-Solid Separation and Oil-Water Separation in Unconventional Heavy Oil Production Process

Unconventional heavy oil ores (UHO) have been considered an important part of petroleum resources and an alternative source of chemicals and energy supply. Due to the participation of water and extractants, oil-solid separation (OSS) and oil-water separation (OWS) processes are inevitable in the industrial separation processes of UHO. Therefore, this critical review systematically reviews the basic theories of OSS and OWS, including solid wettability, contact angle, oil-solid interactions, structural characteristics of natural surfactants and interface characteristics of interfacially active asphaltene film. With the basic theories in mind, the corresponding OSS and OWS mechanisms are discussed. Finally, the present challenges and future research considerations are touched on to provide insights and theoretical fundamentals for OSS and OWS. Additionally, this critical review might even be useful for the provision of a framework of research prospects to guide future research directions in laboratories and industries that focus on the OSS and OWS processes in this important heavy oil production field.

Recovery of extra-heavy oil and minerals from carbonate asphalt rocks by reactive extraction

Quite different from the Canadian oil sands, the Indonesian asphalt rocks proved to be carbonate unconventional oil ores. The strong interactions between asphalt and minerals make water-based extraction work poorly in separating this kind of ore. Herein, a reactive extraction process has been proposed to separate asphalt and mineral solids from the ores through dissolving the mineral solids (i.e., carbonate minerals, metal oxides, etc.) by acids (formic acid). It is evidenced that most of the asphalt could be recovered and collected on the top of the solution by generated CO₂. What's more, the unreacted formic acid could be recycled in this process. The dissolved metal ions could be efficiently recovered to obtain different by-products by chemical settling and crystallization. The amount of residual solids settled at the bottom of the reactor is very small. Further tests show that the reaction efficiency is highly dependent on the operational conditions, including temperature, stirring rate, acid dosage, concentration of acid, etc. It is also found that the reaction could allow minerals to be redistributed in different phases. Although some metal elements could be dissolved into solution, elements such as Fe, Al, S, Si, and Ti are observed to accumulate in asphalt froth. In addition to reacting with minerals, formic acid is also found to reduce asphalt viscosity. This reduction improves the reaction efficiency. Based on primary evaluations, the above findings suggest that the reactive extraction would be a potential process to exploit the Indonesian asphalt rocks (or other similar ores) due to its full recovery to all materials.

A reactive extraction was applied to recover heavy and minerals from carbonate asphalt rocks.