Silica nanofluid flooding for enhanced oil recovery in sandstone rocks

Enhanced oil recovery is proposed as a solution for declining oil production. One of the advanced trends in the petroleum industry is the application of nanotechnology for enhanced oil recovery. Silica nanoparticles (SiNPs) are believed to have the ability to improve oil production, while being environmentally friendly and of natural composition to sandstone oil reservoirs.In our work, we investigated the effect of silica nanoparticles flooding on the amount of oil recovered. Experiments were carried using commercial silica of approximately 20 nm in size. We used sandstone cores in the core flooding experiments. For one of the cores tertiary recovery is applied where brine imbibition was followed by nanofluid imbibition. While in the other cores secondary recovery was applied where primary drainage is directly followed by nanofluid imbibition. We investigated the effect of concentration of nanofluid on recovery; in addition, residual oil saturation was obtained to get the displacement efficiency. Silica nanofluid of concentration 0.01 wt%, 0.05 wt%, 0.1 wt% and 0.5 wt% were studied.The recovery factor improved with increasing the silica nanofluid concentration until optimum concentration was reached. The maximum oil recovery was achieved at optimum silica nanoparticles concentration of 0.1 wt%. The ultimate recovery of initial oil in place increased by 13.28% when using tertiary flooding of silica nanofluid compared to the recovery achieved by water flooding alone. Based on our experimental study, permeability impairment was investigated by studying the silica nanoparticles concentration, and the silica nanofluid injection rate. The permeability was measured before and after nanofluid injection. This helped us to understand the behavior of the silica nanoparticles in porous media. Results showed that silica nanofluid flooding is a potential tertiary enhanced oil recovery method after water flooding has ceased. Keywords: Enhanced oil recovery (EOR), Porous media, Dispersed silica nanoparticle, Nanoflooding, Nanoparticles stability, Nanoflui

Performance of Sprayed PVDF-Al2O3 Composite Coating for Industrial and Civil Applications

Because of their great water repellency, Superhydrophobic coatings have a major impact on a variety of industrial applications. The current study’s key originality is the development of low-cost, stable, superhydrophobic, and corrosion-resistant composite coatings. In the present work, polyvinylidene fluoride (PVDF)/Al2O3 composite coatings were produced using the spray technique to investigate the wettability and corrosion behavior of the coated materials for industrial and civil applications. PVDF was mixed with various concentrations of Al2O3 nanoparticles, and the mixture was sprayed onto steel, aluminum, and glass substrates. The wettability and morphology of the coated surfaces were investigated using the sessile droplet method and scanning electron microscopy, respectively. The corrosion resistance of bare substrates was compared to that of those coated with PVDF alone and those coated with PVDF/Al2O3 nanoparticles using Tafel polarization techniques. The force of adhesion between the coat and the substrates was measured in pounds per square inch. A nanoindentation test was also used to measure the hardness of the coating layer. The PVDF/Al2O3 coated steel showed a significantly higher water contact angle and lower contact angle hysteresis, reaching 157 ± 2° and 7 ± 1°, respectively, compared to the coated aluminum and glass substrates. Corrosion test results showed that the superhydrophobic PVDF/Al2O3 coatings had a much higher corrosion protection efficiency for steel and aluminum than that of the PVDF ones. The PVDF/Al2O3 coated substrates showed moderate but still acceptable adhesion between the coating layer and the substrates. Moreover, the PVDF/Al2O3 coatings had much better mechanical properties than the PVDF only coatings. Such type of coating could be a promising candidate for possible industrial and civil applications

Serum endoglin as a marker in hepatocellular carcinoma

Introduction Hepatitis C viral (HCV) infection is a major risk factor for liver cirrhosis, liver failure, and hepatocellular carcinoma (HCC). A number of laboratory-based methods has been developed for the noninvasive diagnostic evaluation of HCC. Endoglin (CD105) is a homodimeric membrane glycoprotein expressed on endothelial cells that can bind to transforming growth factor-b1 and transforming growth factor-b3. Aim of the study The aim of this study was to evaluate the diagnostic value of endoglin and alpha-fetoprotein (AFP) in patients with chronic HCV infection with and without HCC. Patients and methods A total of 50 HCV patients were chosen and divided into two groups, group I (26 cirrhotic patients) and group II (24 HCC patients), and compared with group III (10 healthy volunteers) as controls. For all participants, thorough clinical examination, blood picture, liver function tests, HCV antibody, AFP, and serum endoglin were performed. Abdominal ultrasound, abdominal triphasic computed tomographic (CT) scan, and liver biopsy for those diagnosed HCC by triphasic CT were performed. Results We found highly significant increase in serum endoglin in HCV patients with HCC (group II) compared with HCV patients with liver cirrhosis (group I) and controls (group III). There was significant positive correlation between serum endoglin and aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, total bilirubin, and AFP. In addition, there was significant negative correlation between serum endoglin and hemoglobin, albumin, and prothrombin concentration. The cutoff value for serum AFP for which HCC is suspected was greater than 250 ng/ml with sensitivity 79% and specificity 89%, whereas the cutoff value for serum endoglin was greater than 10.57 ng/ml with sensitivity 70% and specificity 81%. Conclusion Serum Endoglin is a promising tumor marker that may be used with serum AFP as noninvasive technique to aid diagnosis of HCC