In-situ heavy and extra-heavy oil recovery: A review

Surfactant flooding is an important technique used in enhanced oil recovery to reduce the amount of oil in pore space of matrix rock. Surfactants are injected to mobilize residual oil by lowering the interfacial tension between oil and water and/or by the wettability alteration from oil-wet to water-wet. A large number of cationic, anionic, non-ionic, and amphoteric surfactants have been investigated on a laboratory scale under different conditions of temperature and salinity. Selection of the appropriate surfactant is a challenging task, and surfactants have to be evaluated by a series of screening techniques. Different types of surfactants along with their limitations are reviewed with particular emphasis on the phase behavior, adsorption, interfacial tension, and structure–property relationship. Factors affecting the phase behavior, interfacial tension, and wettability alteration are also discussed. Field applications of surfactants for chemical enhanced oil recovery in carbonate and sandstone reservoi...

Review on Surfactant Flooding: Phase Behavior, Retention, IFT, and Field Applications

The injected fluids in secondary processes supplement the natural energy present in the reservoir to displace oil. The recovery efficiency mainly depends on the mechanism of pressure maintenance. However, the injected fluids in tertiary or enhanced oil recovery (EOR) processes interact with the reservoir rock/oil system. Thus, EOR techniques are receiving substantial attention worldwide as the available oil resources are declining. However, some challenges, such as low sweep efficiency, high costs and potential formation damage, still hinder the further application of these EOR technologies. Current studies on nanoparticles are seen as potential solutions to most of the challenges associated with these traditional EOR techniques. This paper provides an overview of the latest studies about the use of nanoparticles to enhance oil recovery and paves the way for researchers who are interested in the integration of these progresses. The first part of this paper addresses studies about the major EOR mechanisms of nanoparticles used in the forms of nanofluids, nanoemulsions and nanocatalysts, including disjoining pressure, viscosity increase of injection fluids, preventing asphaltene precipitation, wettability alteration and interfacial tension reduction. This part is followed by a review of the most important research regarding various novel nano-assisted EOR methods where nanoparticles are used to target various existing thermal, chemical and gas methods. Finally, this review identifies the challenges and opportunities for future study regarding application of nanoparticles in EOR processes.

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Application of Nanoparticles in Enhanced Oil Recovery: A Critical Review of Recent Progress

Wettability alteration of oil-wet carbonate by silica nanofluid.

Adsorption of surfactants on sand surface in enhanced oil recovery: Isotherms, kinetics and thermodynamic studies

Chemical flooding is a promising technique for enhanced heavy-oil recovery, especially for reservoirs where thermal methods are not feasible. This paper discusses results of a laboratory investigation, including sandpack flooding experiments and micromodel flooding studies, for assessing the suitability and effectiveness of alkaline flooding and alkaline–surfactant (AS) flooding for heavy-oil recovery. The sandpack flood results show that the tertiary oil recovery of AS flooding is lower than those of alkaline-only flooding, although the interfacial tension between the heavy oil and AS system can be reduced to be ultralow. The micromodel tests indicate that the mechanisms for enhanced oil recovery by alkaline flooding are the penetration of the alkaline solution into the crude oil and the subsequent formation of water-in-oil (W/O) droplet flow that tend to reduce the mobility of the water phase and damp viscous fingering, leading to the improvement of sweep efficiency. However, the formation of W/O drople...

Comparative Effectiveness of Alkaline Flooding and Alkaline–Surfactant Flooding for Improved Heavy-Oil Recovery

Potential of alkaline flooding to enhance heavy oil recovery through water-in-oil emulsification

Zeta potential of limestone in a large range of salinity

In this study, the microscopic displacement mechanisms of alkaline flooding for enhanced heavy-oil recovery are investigated using a micromodel. It has been observed that alkaline flooding exhibits a better sweep efficiency than waterflooding, and the serious viscous fingering is significantly reduced. The main microscopic mechanisms of alkaline flooding for enhanced heavy-oil recovery are that the alkaline solution penetrates in crude oil and water drops are, subsequently, formed inside the oil phase, which can improve the mobility ratio and, thus, lead to the improvement of sweep efficiency. The higher the alkaline concentration, the more easily the alkaline solution penetrates in the oil phase. Therefore, a greater improvement in sweep efficiency can be obtained using a higher concentration of alkali. The primary mechanism of the formation of the water drop inside the oil phase during alkaline flooding is related to the interfacial interaction between alkali and heavy oil, which not only results in the...

Guicai Zhang

Papers

Comparative Effectiveness of Alkaline Flooding and Alkaline–Surfactant Flooding for Improved Heavy-Oil Recovery

Potential of alkaline flooding to enhance heavy oil recovery through water-in-oil emulsification

Zeta potential of limestone in a large range of salinity

Analysis of Microscopic Displacement Mechanisms of Alkaline Flooding for Enhanced Heavy-Oil Recovery

Study on organic alkali-surfactant-polymer flooding for enhanced ordinary heavy oil recovery