Evaluating the potential of natural surfactants in the petroleum industry: the case of hydrophobins

Abstract

Enhancing oil recovery from currently available reservoirs is a major issue for petroleum companies. Among the possible strategies towards this, chemical flooding through injection of surfactants into the wells seems to be particularly promising, thanks to their ability to reduce oil/water interfacial tension that promotes oil mobilization. Environmental concerns about the use of synthetic surfactants led to a growing interest in their replacement with surfactants of biological origin, such as lipopeptides and glycolipids produced by several microorganisms. Hydrophobins are small amphiphilic proteins produced by filamentous fungi with high surface activity and good emulsification properties, and may represent a novel sustainable tool for this purpose. We report here a thorough study of their stability and emulsifying performance towards a model hydrocarbon mixture, in conditions that mimic those of real oil reservoirs (high salinity and high temperature). Due to the moderate interfacial tension reduction induced in such conditions, the application of hydrophobins in enhanced oil recovery techniques does not appear feasible at the moment, at least in absence of co-surfactants. On the other hand, the obtained results showed the potential of hydrophobins in promoting the formation of a gel-like emulsion 'barrier' at the oil/water interface.

Cerato-Platanins from Marine Fungi as Effective Protein Biosurfactants and Bioemulsifiers

“…Therefore, as a first approach, the ability of both proteins to stabilize emulsions was verified. Indeed, the obtained E 24 values were comparable to those of other proteins and to commercially available surfactants analyzed in the same way [19,23].…”

“…To investigate the performances of these proteins as emulsifying agents, emulsification tests were performed using Dectol (a mix of Decane-Toluene 65:35, v/v), according the protocol of Blesic et al [19].…”

“…The emulsification capability of samples was investigated at different protein concentrations. In the experiment, 2 mL of Dectol (a mix of Decane-Toluene 65:35, v/v) was added as emulsifying agent to 1 mL of each surfactant protein in 10 mM phosphate buffer (pH 7.0) in 5 mL glass vials [19]. This mixture was homogenized using the IKA T-10 Basic Ultra Turrax Homogenizer IKA-Werke GmbH, Staufen, Germany) for 2 min; then, the stability of the emulsions after 24 h was evaluated.…”

Oleochemicals from Palm Oil for the Petroleum Industry

“…Chemicals (also referred to as micellar) flooding is widely employed due to ease of application and availability of wide range of chemicals. It involves injections of surfactants, polymers and alkali, and their various combination into the reservoirs to mobilize the trapped oil and improve recovery [35].…”

“…ASP flooding involves the injection of a mixture of alkali, surfactant, and polymer into the reservoir. It is an effective chemical EOR technique due to the fact that it employs the synergy of the three techniques [35]. It has been employed in the oil industry to, among others, allow for better sweeping of the reservoir by lowering the interfacial tension (IFT) between oil and water (by the surfactant), alter reservoir rock wettability from oil wet to water wet (using the alkali), and to increase the crude mobility ratio (with the polymer).…”