Study on Acidizing Effect of Cationic β-Cyclodextrin Inclusion Complex with Sandstone for Enhancing Oil Recovery

Advancements in Surfactant Carriers for Enhanced Oil Recovery: Mechanisms, Challenges, and Opportunities

Enhanced oil recovery (EOR) techniques are crucial for maximizing the extraction of residual oil from mature reservoirs. This review explores the latest advancements in surfactant carriers for EOR, focusing on their mechanisms, challenges, and opportunities. We delve into the role of inorganic nanoparticles, carbon materials, polymers and polymeric surfactants, and supramolecular systems, highlighting their interactions with reservoir rocks and their potential to improve oil recovery rates. The discussion includes the formulation and behavior of nanofluids, the impact of surfactant adsorption on different rock types, and innovative approaches using environmentally friendly materials. Notably, the use of metal oxide nanoparticles, carbon nanotubes, graphene derivatives, and polymeric surfacants and the development of supramolecular complexes for managing surfacant delivery are examined. We address the need for further research to optimize these technologies and overcome current limitations, emphasizing the importance of sustainable and economically viable EOR methods. This review aims to provide a comprehensive understanding of the emerging trends and future directions in surfactant carriers for EOR.

Advances of supramolecular interaction systems for improved oil recovery (IOR)

Improved oil recovery (IOR) includes enhanced oil recovery (EOR) and other technologies (i.e. fracturing, water injection optimization, etc.), have become important methods to increase the oil/gas production in petroleum industry. However, conventional flooding systems always encounter the problems of low efficiency, high cost and complicated synthetic procedures for harsh reservoirs conditions. In recent decades, the supramolecular interactions are introduced into IOR processes to simplify the synthetic procedures, alter their structures and properties with bespoke functionalities and responsiveness suitable for different conditions. Herein, we primarily review the fundamentals of several supramolecular interactions, including hydrophobic association, hydrogen bond, electrostatic interaction, host-guest recognition, metal-ligand coordination and dynamic covalent bond from intrinsic principles and extrinsic functions. Then, the descriptions of supramolecular interactions in IOR processes from categories and advances are focused on the following variables: polymer, surfactant, surfactant/polymer (SP) complex for EOR and viscoelasticity surfactant (VES) for clean hydraulic fracturing aspects. Finally, the field applications, challenges and prospects for supramolecular interactions in IOR processes are involved and systematically addressed. The development of supramolecular interactions can open the way toward adaptive and evolutive IOR technology, a further step towards the cost-effective production of petroleum industry.

Preparation of Mn2+ Doped Piperazine Phosphate as a Char-Forming Agent for Improving the Fire Safety of Polypropylene/Ammonium Polyphosphate Composites

A piperazine phosphate doped with Mn2+ (HP-Mn), as a new char-forming agent for intumescent flame retardant systems (IFR), was designed and synthesized using 1-hydroxy ethylidene-1,1-diphosphonic acid, piperazine, and manganese acetate tetrahydrate as raw materials. The effect of HP-Mn and ammonium polyphosphate (APP) on the fire safety and thermal stability of polypropylene (PP) was investigated. The results showed that the combined incorporation of 25 wt.% APP/HP-Mn at a ratio of 1:1 endowed the flame retardant PP (PP6) composite with the limiting oxygen index (LOI) of 30.7% and UL-94 V-0 rating. In comparison with the pure PP, the peak heat release rate (PHRR), the total heat release (THR), and the smoke production rate (PSPR) of the PP6 were reduced by 74%, 30%, and 70%, respectively. SEM and Raman analysis of the char residues demonstrated that the Mn2+ displayed a catalytic cross-linking charring ability to form a continuous and compact carbon layer with a high degree of graphitization, which can effectively improve the flame retardancy of PP/APP composites. A possible flame-retardant mechanism was proposed to reveal the synergistic effect between APP and HP-Mn.

Novel Approach for Sandstone Acidizing Using in Situ-Generated Hydrofluoric Acid with the Aid of Thermochemicals

In this study, an in situ-generated hydrofluoric acid (HF) was used for sandstone acidizing, where an acid precursor (ammonium fluoride NH₄F) reacted with a suitable oxidizer (sodium bromates NaBrO₃) in an exothermic reaction. First, the new chemical mixture was prepared to react with pure quartz samples and the reaction effluent was analyzed to identify the presence of Si⁺ ions using the inductively coupled plasma (ICP) technique. Core flooding experiments were performed using Gray Berea sandstone cores (6 in. length and 1.5 in. diameter). A preflush stage of 5 PV of 7 wt % HCl was injected to remove any calcite content in the core. The main chemicals were then flushed for 3 successive cycles of 1 PV each. To assure core integrity, scratch tests and NMR scans were run on the core sample before and after the treatment. The new chemical mixture could dissolve the quartz sample and reduce its weight by 80 mg. The concentration of the dissolved Si⁺ ions was more than 90 ppm. This proves the capability of the chemical mixture to generate HF. The initial core permeability was measured at a stabilized flow rate of 2 cm³/min to be 33 mD. After the acid preflush stage, the core permeability reduced to 31 mD. Core permeability increased immediately after the first treatment cycle and reached 41 mD. At the end, the core flooding results showed a permeability improvement for Gray Berea sandstone cores by almost 40%. The ICP analysis of the effluent showed a total amount of chelated Si⁺ ions of about 10.5 mg. In addition to the high temperature generated in the near-wellbore area, the pressure increased because of the produced nitrogen gas from the exothermic reaction and reached about 600 psi. The scratch test showed an increase in the sample uniaxial compressive strength from 7432 to 9235 psi. The dynamic Poisson's ratio and the dynamic Young's modulus increased as well from 0.17 to 0.19 and from 2159 to 3585 ksi, respectively. The enhancement in the mechanical properties of the core can be attributed to the presence of the potassium element in Berea cores and its solidification reaction with the HF generated. The NMR measurements of the core sample before and after the acidizing process show an increase in the core porosity; however, the core preserved its original pore system. Upon application of this new stimulation technology, the true production potential of sandstone reservoirs can be achieved, well tubular corrosion will be minimized, and handling hazardous chemicals such as HF will be avoided. Most importantly, controlling the reaction rate, by controlling the amount of exothermic chemicals, can ensure deep acid penetration as well.

Density Functional Theory and UPLC/MS/ESI+ studies of the zwitterionic surfactant-Na+ pair formation

The formation in solution of supramolecular complexes type zwitterion-cation have been shown. The industrial grade zwitterion surfactants cocamidopropyl hydroxysultaine and cocamidopropyl betaine with sodium ion were studied. A combined experimental and theoretical point of view was performed, through the use of Ultra-Performance Liquid Chromatography/Mass Spectrometry/ElectroSpray Ionization with positive mode (UPLC/MS/ESI+) analytic technique and Density Functional Theory (DFT) theoretical approach. Then, the supramolecular complex zwitterion-cation-anion triplets are shown to be viable. Mass/Charge (m/z) relationships have been determined through MS/ESI using positive mode as an ionization source, obtaining five and four molecular species for industrial grade sultaine and betaine chemical products, respectively. Also, molecular zwitterion-NaCl complexes were theoretically studied in three different dielectric constants corresponding to water, methanol, and acetone solvents. It was found that acetone, the lower dielectric constant solvent studied, shows the higher interaction energy. In both vacuum neutral, zwitterion-NaCl, and vacuum positive, zwitterion-Na⁺, molecular complexes the interaction of the cocamidopropyl hydroxysultaine pairs is less strong than cocamidopropyl betaine ones.

Development of curcumin-cyclodextrin/cellulose nanocrystals complexes: New anticancer drug delivery systems

The synthesis of curcumin-cyclodextrin/cellulose nanocrystals (CNCx) nano complexes was performed. CNCx were functionalized by ionic association with cationic β-cyclodextrin (CD) and CD/CNCx complexes were used to encapsulate curcumin. Preliminary in vitro results showed that the resulting curcumin-CD/CNCx complexes exerted antiproliferative effect on colorectal and prostatic cancer cell lines, with IC50s lower than that of curcumin alone.