Abdullah S. Sultan

Review on Polymer Flooding: Rheology, Adsorption, Stability, and Field Applications of Various Polymer Systems

Polymer flooding is one of the most promising techniques for the recovery of remaining oil from light oil reservoirs. Water soluble polymers are used to enhance the viscosity of displacing fluid and to improve the sweep efficiency. In this paper, water soluble polymers used for chemical enhanced oil recovery are reviewed. Conventional and novel modified polymers are discussed along with their limitations. The review covers thermal stability, rheology, and adsorption behavior of various polymer systems in sandstone and carbonate reservoirs. Field and laboratory core flooding data of several polymers are covered. The review describes the polymer systems that are successfully applied in low-temperature and low-salinity reservoirs. Comprehensive review of current research activities aiming at extending polymer flooding to high-temperature and high-salinity reservoirs is performed. The review has identified current and future challenges of polymer flooding.

Rheological Study on ATBS-AM Copolymer-Surfactant System in High-Temperature and High-Salinity Environment

Experimental studies were conducted to evaluate the rheological properties of surfactant-polymer (SP) system. This SP system consists of a copolymer of acrylamide (AM) and acrylamido tertiary butyl sulfonate (ATBS) and sodium dodecyl sulphate (SDS) surfactant. Effects of surfactant concentration, temperature, polymer concentration, and salinity on rheological properties of SP system were investigated by means of oscillation and shear measurements. Comparison with classical partially hydrolyzed polyacrylamide (HPAM) was made. For the same temperature range, the viscosity drop for HPAM was about four times higher than the viscosity drop for ATBS-AM copolymer. In deionized water, viscosity of both polymers and SP systems was very high as compared to viscosity in saline water. Viscosity reduction of ATBS-AM copolymer was higher for salts having divalent cations. The SP system showed precipitation in presence of divalent cations. It worked well with monovalent cations even at relatively high salinities. The addition of 0.1% surfactant to the polymer resulted in a 60% decrease in the viscosity. Some interfacial rheological experiments were also carried out to investigate the behaviors on the interface between SP solutions and oil. Addition of 0.1% surfactant showed a 65% decrease in G′ at SP solution-oil interface. SP system consisting of ATBS-AM and SDS showed better performance at high temperature compared to HPAM-SDS system. Due to precipitation, the SP system should be restricted to environment having low divalent cations.

Carbon Nanotubes (CNTs) Nanocomposite Hydrogels Developed for Various Applications: A Critical Review

Interest in the development of polymeric hydrogels impregnated with carbon-nanotubes (CNTs) is growing rapidly in recent times owing to their usefulness in many fields of human endeavor. This review paper serves as an archive of literature reports of several researchers who have worked on polymeric hydrogels embedded with CNTs for diverse applications. The review covers up to date research advancement on the synthesis and characterization properties of CNTs nanocomposite hydrogels. Besides, this review discusses extensively the various fields in which polymeric hydrogels infused with CNTs have been applied. This unprecedented compilation of CNTs nanocomposite hydrogels information into a single revision allows a straightforward comparison of studies performed for diverse applications.

DSC investigation of the gelation kinetics of emulsified PAM/PEI system

Abstract Water production in the oilfields has a negative impact on the production and economy. It is highly desired to shut off water paths without affecting the hydrocarbon zones. Polymer gels are frequently used for water control in oil and gas wells. However, a risk will be taken, which is blocking the oil-producing zones alongside the water zones. Hence, a selective system is proposed, which is based on emulsified polymer gel that contains a water phase which will form a gel, and an oil phase remains mobile to secure the flow of oil. The gels formed in situ by breaking up of an emulsified gel made of an oil phase and an aqueous water-soluble polymers (gelant). Breaking of the emulsion and the subsequent gelation is a function of temperature, time, salinity of mixing water, and concentration of the various components, including surfactants and salts. The gelant was prepared by mixing polyacrylamide (PAM) with a mixing brine and then adding polyethylenimine (PEI) as a cross-linker. Diesel and a surfactant were used to form the emulsified gel. In this study, differential scanning calorimetry (DSC) is utilized to study the emulsified gel reaction kinetics for the first time. The rate of increase in temperature and the final temperature used in DSC were chosen to approximate (mimic) the field injection conditions. The impact of parameters such as temperature, water salinity, surfactant, and retarder type on gelation is investigated to compare the kinetics of the polymeric gels and their emulsified forms. At a given emulsifier concentration, emulsified PAM/PEI has a lower rate of cross-linking (gelation) when compared to that of PAM/PEI. This is most likely due to less heat conducted to the gelant. As a result, the cross-linking density will be less. Ammonium chloride is found to be more efficient than sodium chloride in retarding the gelation process. The type of surfactant is an additional parameter which can be used to control gelation in emulsified gel systems.

Model-based analysis of polymeric membranes performance in high pressure CO2 removal from natural gas

Penetrant-induced plasticization is known to be one of the main challenges of high-pressure membrane separation of CO2 from natural gas. Therefore, a procedure that integrates experimental and mathematical models was developed to analyze the performance of polymeric membranes for removal of CO2 at high feed pressure. A semi-empirical model for estimating plasticization pressure and permeability parameters at plasticization from permeation test data was proposed and tested on more than 90 polymeric membranes. Three model parameters (α1, α2 , and α3) were obtained and used to evaluate membrane performance in terms of plasticization pressure as well as permeability and productivity loss at plasticization pressure. Results from the analysis revealed that this set of parameters can be simply employed to evaluate membrane performance at high pressure.

Revisiting Reaction Kinetics and Wormholing Phenomena During Carbonate Acidising

Wormholing during matrix acidizing of carbonate reservoirs is known to be predominantly mass transfer limited. Mass transfer coefficient, controlled by (1) the fluid injection rate and (2) the acid diffusion coefficient, dictates the speed and profile of the wormholes. Injection rate is easily obtained from the job execution, whereas the diffusion coefficient is intrinsically a hidden parameter of the fluid and reaction conditions. Acid diffusion coefficient data used in modeling the wormholing processes are commonly obtained at 1000 psi system pressure, which is too low to represent realistic reservoir conditions. In order to properly quantify the acid penetration inside the formation, the diffusion coefficient of acid acquired from high-pressure reservoir conditions should be used. In this study, we investigate the effects of diffusion coefficients of HCl acid as it reacts with calcite. We use a rotating disk apparatus to obtaine the CO2-impacted kinetics at downhole conditions. The test results show that the diffusion coefficient of the HCl acid is much lower at high pressure than low pressure at the same concentration due to the impact of CO2 produced by the HCl-carbonate reaction. At higher pressure, more CO2 tends to stay in an aqueous phase, which slows down the reaction of HCl and the carbonate formation. For example, at 150 °F, the diffusion coefficient of 15% HCl at 3,000 psi reduced 50% of its original value when at 1,000 psi of 15% HCl. This new set of kinetics data is then implemented in a 3D wormholing model to predict wormhole morphology and penetration velocity. The model uses a CT-scan rendered porosity field to capture the finer details of the rock fabric. Simulation results of fluid flow coupled with reaction provide new insights on how acidizing design models should be improved to more accurately quantify wormhole penetration, which then leads to more accurate production forecasts.

Recent Advances in Nanoparticles Enhanced Oil Recovery: Rheology, Interfacial Tension, Oil Recovery, and Wettability Alteration

Chemically enhanced oil recovery methods are utilized to increase the oil recovery by improving the mobility ratio, altering the wettability, and/or lowering the interfacial tension between water and oil. Surfactants and polymers have been used for this purpose for the last few decades. Recently, nanoparticles have attracted the attention due to their unique properties. A large number of nanoparticles have been investigated for enhanced oil recovery applications either alone or in combination with surfactants and/or polymers. This review discusses the various types of nanoparticles that have been utilized in enhanced oil recovery. The review highlights the impact of nanoparticles on wettability alteration, interfacial tension, and rheology. The review also covers the factors affecting the oil recovery using nanoparticles and current challenges in field implementation.

Membrane Separation of CO2 from Natural Gas: A State-of-the-Art Review on Material Development

Natural gas (NG) processing and membrane technology are two very important fields that are of great significance due to increasing demand for energy as well as separation of gas mixtures. While NG is projected to be the number one primary source of energy by 2050, membrane separation is a commercially successful competitor to other separation techniques for energy efficient gas separation processes [1]. Most of the NG produced in the world is coproduced with acid gases such as CO2 which need to be removed to increase the caloric value of NG. A comprehensive review of research efforts in CO2 separation from natural gas is required to capture details of the current scientific and technological progresses on the development of new membrane materials with better separation performance, and the improvement of properties of the existing ones. This paper presents the progress that has been achieved in eliminating the limitations that dominate the large scale application of membrane materials at the present time. Various polymers that have been developed to resist plasticization and the method employed to fabricate these polymers are highlighted. Also the range of plasticization pressures (together with corresponding selectivities and permeabilities at these pressures) that have so far been achieved by these fabrication methods is presented. It is believed that this review will serve as a good reference source especially for research in design and development of membrane materials with better resistance to CO2-induced plasticization.

Polymeric Surfactants and Emerging Alternatives used in the Demulsification of Produced Water: A Review

ABSTRACT Stable emulsions are frequently encountered in oil production and cause a series of environmental and operational issues. Chemical demulsification is widely used for the separation of oil from water or removal of water from oil. The chemicals used in the demulsification process have a strong affinity to the oil-water interface. This review presents the various types of chemical demulsifiers used for the demulsification of water-in-oil and oil-in-water emulsions. The review covers the relevant properties of polymeric surfactants such as polyether, dendrimers, and natural biodegradable polymeric surfactants. In addition, emerging alternatives like nanoparticles-based demulsifiers and ionic liquids are also reviewed. The factors affecting the demulsification efficiency of these demulsifiers and structure-property relationships are discussed. Copolymers with high hydrophilic content and molecular weight are more efficient demulsifiers. Similarly, the position isomerism (same carbon skeleton and functional groups but a different location of functional groups) strongly affects the HLB and demulsification performance. Generally, dendrimers show better performance compared to linear polymeric surfactants due to their relatively higher interfacial activity, better penetrability, and a larger number of reactive terminal groups. Techniques used to evaluate the performance of demulsifiers are also covered. The review also highlights the current developments and future prospects of chemical demulsifiers.

Sulfonated Poly(Ether Ether Ketone) (SPEEK): A Promising Membrane Material for Polymer Electrolyte Fuel Cell

Nafion has been the material of choice for polymer electrolyte membrane fuel cells (PEMFCs), but during the last two decades, considerable efforts have been made to find an alternative with similar or better physicochemical properties and with lower manufacturing cost. Developments over the last two decades have resulted to some novel membrane materials with improved properties. Among the materials researched and developed, sulfonated poly(ether ether ketone) (SPEEK) has been the most promising and has the potential for commercialization. In this chapter, the properties of SPEEK and its characteristics are discussed.