Impact of nanoparticles on the CO2-brine interfacial tension at high pressure and temperature

Hypothesis: Nanofluid flooding has been identified as a promising method for enhanced oil recovery (EOR) and improved Carbon geo-sequestration (CGS). However, it is unclear how nanoparticles (NPs) influence the CO2-brine interfacial tension (γ), which is a key parameter in pore-to reservoirs-scale fluid dynamics, and consequently project success. The effects of pressure, temperature, salinity, and NPs concentration on CO2-silica (hydrophilic or hydrophobic) nanofluid γ was thus systematically investigated to understand the influence of nanofluid flooding on CO2 geo-storage. Experiments: Pendant drop method was used to measure CO2/nanofluid γ at carbon storage conditions using high pressure-high temperature optical cell. Findings: CO2/nanofluid γ was increased with temperature and decreased with increased pressure which is consistent with CO2/water γ. The hydrophilicity of NPs was the major factor; hydrophobic silica NPs significantly reduced γ at all investigated pressures and temperatures while hydrophilic NPs showed only minor influence on γ. Further, increased salinity which increased γ can also eliminate the influence of NPs on CO2/nanofluid γ. Hence, CO2/brine γ has low, but, reasonable values (higher than 20 mN/m) at carbon storage conditions even with the presence of hydrophilic NPs, therefore, CO2 storage can be considered in oil reservoirs after flooding with hydrophilic nanofluid. The findings of this study provide new insights into nanofluids applications for enhanced oil recovery and carbon geosequestration projects

Wettability alteration of oil-wet carbonate by silica nanofluid

Changing oil-wet surfaces toward higher water wettability is of key importance in subsurface engineering applications. This includes petroleum recovery from fractured limestone reservoirs, which are typically mixed or oil-wet, resulting in poor productivity as conventional waterflooding techniques are inefficient. A wettability change toward more water-wet would significantly improve oil displacement efficiency, and thus productivity. Another area where such a wettability shift would be highly beneficial is carbon geo-sequestration, where compressed CO2 is pumped underground for storage. It has recently been identified that more water-wet formations can store more CO2. We thus examined how silica based nanofluids can induce such a wettability shift on oil-wet and mixed-wet calcite substrates. We found that silica nanoparticles have an ability to alter the wettability of such calcite surfaces. Nanoparticle concentration and brine salinity had a significant effect on the wettability alteration efficiency, and an optimum salinity was identified, analogous to that one found for surfactant formulations. Mechanistically, most nanoparticles irreversibly adhered to the oil-wet calcite surface (as substantiated by SEM–EDS and AFM measurements). We conclude that such nanofluid formulations can be very effective as enhanced hydrocarbon recovery agents and can potentially be used for improving the efficiency of CO2 geo-storage

Nanoparticles influence on wetting behaviour of fractured limestone formation

Nanoparticles have gained considerable interest in recent times for oil recovery purposes owing to significant capabilities in wettability alteration of reservoir rocks. Wettability is a key factor controlling displacement efficiency and ultimate recovery of oil. The present study investigates the influence of zirconium (IV) oxide (ZrO2) and nickel (II) oxide (NiO) nanoparticles on the wetting preference of fractured (oil-wet) limestone formations. Wettability was assessed through SEM, AFM and contact angle. The potentials of the nanoparticles to alter oil-wet calcite substrates water wet, was experimentally tested at low nanoparticle concentrations (0.004–0.05 wt%). Quite similar behaviour was observed for both nanoparticles at the same particle concentration; while ZrO2 demonstrated a better efficiency by altering strongly oil-wet (water contact angle θ=152°) calcite substrates into a strongly water-wet (θ=44°) state, NiO changed wettability to an intermediate-wet condition (θ=86°) at 0.05 wt% nanoparticle concentration. We conclude that ZrO2 is very efficient in terms of inducing strong water-wettability; and ZrO2 based nanofluids have a high potential as EOR agents

Progesterone Therapy Administered 24 hours Before Embryo Transfer in ICSI Cycle Improves Embryo Implantation and Pregnancy in Women With Luteal Phase Defect.

Background: Ovulation induction by human menopausal gonadotrophin (HMG) results in temporal luteal phase defect. Luteal support therapies are required to support embryo implantation in stimulated cycle especially in luteal phase defect infertile women.  Objective: The objective of the present study was to investigate the clinical significance of progesterone, aspirin and HCG on human embryo implantation in women with luteal phase defect following ICSI and embryo transfer (ET). Patients and Methods: The female patients were divided into six groups depending on the type of the luteal support protocols (LSP). Group 1 (No= 54), received 10 mg oral progesterone (P), group 2 (No= 35) received P plus HCG, group 3 (No= 59) received P plus HCG plus oral aspirin, group 4 (No= 47) received vaginal P administered 24 hours before embryo transfer plus oral aspirin, group 5 (No= 40)  received vaginal P administered 12 hours after embryo transfer plus oral aspirin and group 6 (No= 46) received intramuscular P plus oral aspirin. The LSP were continued for at least 12 weeks, when the BHCG test was positive, (tested two weeks after embryo transfer). Results: Statistical analysis of the clinical data showed no significant differences between the LSP in regard to patient's age, body mass index (B/M2), basal FSH/LH ratio and estradiol concentration at the day of HCG injection. The ICSI rate, percentages of embryos developed in vitro, and the numbers of the transferable quality embryos were similar in all groups (P>0.05). The pregnancy rate was significantly higher (P < 0.05), in group 4 compared to other groups (38.66% versus 24.51%(G 1), 22.53% (G 2), 28.66% (G 3), 25% (G 5), 21.60% (G 6). The percentages of viable fetal sac development per patient were 31.49 (17/54), in G 1, 42.86 (15/35), in G 2, 49.16 (29/59), in G 3, 59.58 (28/47), in G 4, 32.50 (13/40), in G 5, and 34.79 (16/46), G 6. The percent of viable gestation sac was significantly higher in group 4 compared to other groups (P < 0.05). Concl u s i o n s : The administration of 400 mg /day vaginal progesterone 24 hours before ET and 100 mg/day aspirin five days after ET results in significant improvements in pregnancy and embryo implantation rates and development of viable fetuses in luteal phase defect infertile women undergoing ICSI-ET

Nanotechnology and global energy demand: challenges and prospects for a paradigm shift in the oil and gas industry.

The exploitation of new hydrocarbon discoveries in meeting the present global energy demand is a function of the availability and application of new technologies. The relevance of new technologies is borne out of the complex subsurface architecture and conditions of offshore petroleum plays. Conventional techniques, from drilling to production, for exploiting these discoveries may require adaption for such subsurface conditions as they fail under conditions of high pressure and high temperature. The oil and gas industry over the past decades has witnessed increased research into the use of nanotechnology with great promise for drilling operations, enhanced oil recovery, reservoir characterization, production, etc. The prospect for a paradigm shift towards the application of nanotechnology in the oil and gas industry is constrained by evolving challenges with its progression. This paper gave a review of developments from nano-research in the oil and gas industry, challenges and recommendations

Oil-water interfacial tensions of silica nanoparticle-surfactant formulations

© 2017 Carl Hanser Publisher, Munich. The implementation of nanotechnology in all industries is one of most significant research fields. Nanoparticles have shown a promising application in subsurface fields. On the other hand, various surfactants have been used in the oil industry to reduce oil/water interfacial tension and also widely used to stabilize the nano-suspensions. The primary objective of this study was to investigate the improvements of surfactants ability in term of inter facial tension (?) reduction utilizing addition of silicon dioxide nanoparticles at different temperatures and salinity. The pendant drop technique has been used to measure ? and electrical conductivity has been used to measure the critical micelle concentration (CMC). The synergistic effects of surfactant-nanoparticles, salt-nanoparticles, and surfactant-salt-nanoparticles on ? reduction and the critical micelle concentration of the surfactants have been investigated. Extensive series of experiments for ? and CMC measurements were performed. The optimum condition for each formulation is shown. We conclude that nanoparticles-surfactant can significantly reduce ? if correctly formulated