Effect of mineralogy on the adsorption characteristics of surfactant—Reservoir rock system

Investigation of ionic liquid adsorption and interfacial tension reduction using different crude oils; effects of salts, ionic liquid, and pH

The results revealed the significant effect of NaCl, KCl, CaCl2, MgCl2, CaSO4, MgSO4, and Na2SO4 and pH values of 3.5-11 on the interfacial tension (IFT) reduction using three types of neutral, acidic, and basic crude oils, especially for acidic crude oil (crude oil II) as the pH was changed from 3.5 to 11 (due to saponification process). The findings showed the highest impact of pH on the IFT of crude oil II with a reducing trend, especially for the pH 11 when no salts exist. The results revealed that the salts except MgCl2 and CaCl2 led to a similar IFT variation trend for the case of distilled water/crude oil II. For the MgCl2 and CaCl2 solutions, a shifting point for IFT values was inevitable. Besides, the dissolution of 1-dodecyl-3-methyl imidazolium chloride ([C12mim][Cl]) with a concentration of 100-1000 ppm eliminates the effect of pH on IFT which leads to a reducing trend for all the examined crude oils with minimum IFT of 0.08 mN/m. Finally, the [C12mim][Cl] adsorption (under pH values) for crude oils using only Na2SO4 was measured and the minimum adsorption of 0.41 mg surfactant/g Rock under the light of saponification process was obtained.

Comprehensive review on surfactant adsorption on mineral surfaces in chemical enhanced oil recovery

With the increasing demand for efficient extraction of residual oil, enhanced oil recovery (EOR) offers prospects for producing more reservoirs' original oil in place. As one of the most promising methods, chemical EOR (cEOR) is the process of injecting chemicals (polymers, alkalis, and surfactants) into reservoirs. However, the main issue that influences the recovery efficiency in surfactant flooding of cEOR is surfactant losses through adsorption to the reservoir rocks. This review focuses on the key issue of surfactant adsorption in cEOR and addresses major concerns regarding surfactant adsorption processes. We first describe the adsorption behavior of surfactants with particular emphasis on adsorption mechanisms, isotherms, kinetics, thermodynamics, and adsorption structures. Factors that affect surfactant adsorption such as surfactant characteristics, solution chemistry, rock mineralogy, and temperature were discussed systematically. To minimize surfactant adsorption, the chemical additives of alkalis, polymers, nanoparticles, co-solvents, and ionic liquids are highlighted as well as implementing with salinity gradient and low salinity water flooding strategies. Finally, current trends and future challenges related to the harsh conditions in surfactant based EOR are outlined. It is expected to provide solid knowledge to understand surfactant adsorption involved in cEOR and contribute to improved flooding strategies with reduced surfactant loss.

Advanced Switchable Molecules and Materials for Oil Recovery and Oily Waste Cleanup

Advanced switchable molecules and materials have shown great potential in numerous applications. These novel materials can express different states of physicochemical properties as controlled by a designated stimulus, such that the processing condition can always be maintained in an optimized manner for improved efficiency and sustainability throughout the whole process. Herein, the recent advances in switchable molecules/materials in oil recovery and oily waste cleanup are reviewed. Oil recovery and oily waste cleanup are of critical importance to the industry and environment. Switchable materials can be designed with various types of switchable properties, including i) switchable interfacial activity, ii) switchable viscosity, iii) switchable solvent, and iv) switchable wettability. The materials can then be deployed into the most suitable applications according to the process requirements. An in-depth discussion about the fundamental basis of the design considerations is provided for each type of switchable material, followed by details about their performances and challenges in the applications. Finally, an outlook for the development of next-generation switchable molecules/materials is discussed.

Toward Reducing Surfactant Adsorption on Clay Minerals by Lignin for Enhanced Oil Recovery Application

The significant loss of surfactants during reservoir flooding is a challenge in oil field operations. The presence of clay minerals affects the surfactant performance, resulting in surfactant losses. This is because the mineralogical composition of the reservoir results in unpredicted adsorption quantity. Therefore, this paper seeks to investigate Aerosol-OT's adsorption on different quartz/clay mineral compositions during the flow. Also, it investigates adsorption mitigation by preflushing with lignin. The dynamic experiments were conducted on sand packs composed of quartz-sand and up to a 7% clay mineral content. The results obtained from the surfactant losses were compared with/without lignin preflush at different pH values. The main observation was the direct relationship between increasing the composition of clay minerals and the surfactant pore volume required to overcome the adsorption. The highest adsorption calculated was 46 g/kg for 7% kaolinite. Moreover, lignin successfully reduced the adsorption of Aerosol-OT by 60%. Therefore, the results demonstrate that the effects of the clay mineral content on adsorption could be efficiently minimized using lignin at a high pH.

Challenges and future of chemical assisted heavy oil recovery processes

The primary method for heavy oil and bitumen production across the world is still in-situ steam-based technology. There are some drawbacks associated with steam-driven heavy oil recovery methods such as cyclic steam stimulation (CSS), steam flooding, and steam-assisted gravity drainage (SAGD). These cons include the high greenhouse gas footprint, low heavy oil/bitumen recovery, and difficulty in stop operation in emergency conditions. There exists a need for an improved method for recovering residual oils after applying steam injection. One of the potential technologies for doing this is chemical assisted heavy oil recovery, especially alkaline and surfactant additives. But the challenging question is how to develop a chemical-based oil recovery method considering long-term steam-rock interactions. Several associated issues of chemical additives, including adsorption behavior of surfactant at reservoir conditions and thermal stability of surfactant at steam chamber temperature, make this question more complex. This paper addresses all these concerns and provides solid knowledge regarding this technology. We delve into newly formulated chemicals for coupling with thermal oil recovery techniques that are still limited to lab-scale research, with the need for further studies. This critical review also provides the opportunities and challenges associated with chemical assisted heavy oil/bitumen production in a post-steam injection scenario. Finally, different aspects of such a method are covered in this review, along with practical information on field trials and best practices across the world.