Electrostatic Origins of CO2-Increased Hydrophilicity in Carbonate Reservoirs

Injecting CO2 into oil reservoirs appears to be cost-effective and environmentally friendly due to decreasing the use of chemicals and cutting back on the greenhouse gas emission released. However, there is a pressing need for new algorithms to characterize oil/brine/rock system wettability, thus better predict and manage CO2 geological storage and enhanced oil recovery in oil reservoirs. We coupled surface complexation/CO2 and calcite dissolution model, and accurately predicted measured oil-on-calcite contact angles in NaCl and CaCl2 solutions with and without CO2. Contact angles decreased in carbonated water indicating increased hydrophilicity under carbonation. Lowered salinity increased hydrophilicity as did Ca2+. Hydrophilicity correlates with independently calculated oil-calcite electrostatic bridging. The link between the two may be used to better implement CO2 EOR in fields

Multi-hop wireless transmission with half duplex and imperfect full duplex relays7'th International Symposium on Telecommunications (IST'2014)

A multi-hop wireless transmission system employing both half duplex and imperfect full duplex relays is proposed. In this scheme, which uses Ksub-channels for transmission and reception over Rayleigh fading channels, we aim to mitigate the most dominant source of interference in each node by allocating different sub-channels to various groups of nodes. The outage probability of the proposed scheme under decode and forward relaying is analyzed and a closed form expression is obtained and validated by simulation. The proposed multi-hop transmission scheme based on full and half duplex relays, although less complex, still improves the outage probability of the network in comparison to complete full duplex multi-hop relaying

Prediction of HCV load using genotype, liver biomarkers, and clinical symptoms by a mathematical model in patients with HCV infection

Hepatitis C virus (HCV) infection is a major public health problem with about 1.75 million new HCV cases and 71 million chronic HCV infections worldwide. The study aimed to evaluate clinical, serological, molecular, and liver markers to develop a mathematical predictive model for the quantification of the HCV viral load in chronic HCV infected patients. In this cross-sectional study, blood samples were taken from 249 recently diagnosed HCV-infected subjects and were tested for liver condition, viral genotype, and HCV RNA load. Receiver operating characteristics (ROC) curves and multiple linear regression analysis were used to predict the HCV-RNA load. Genotype 3 followed by genotype 1 were the most prevalent genotypes in Mashhad, Northeastern Iran. The maximum levels of viral load were detected in the mixed genotype group, and the lowest levels in the undetectable genotype group. The log of the HCV viral load was significantly associated with thrombocytopenia and higher serum levels of alanine transaminase (ALT). In addition, the log HCV RNA was significantly higher in patients with arthralgia, fatigue, fever, vomiting, or dizziness. Moreover, genotype 3 was significantly associated with icterus. A ROC curve analysis revealed that the best cut-off points for serum levels of aspartate aminotransferase (AST), ALT, and alkaline phosphatase (ALP) were >31, >34, and ≤246 IU/L, respectively. Sensitivity, specificity, and positive predictive values for AST were 87.7%, 84.36%, and 44.6%, for ALT they were 83.51%, 81.11%, and 36%, and for ALP were 72.06%, 42.81%, and 8.3%, respectively. A mathematical regression model was developed that could estimate the HCV-RNA load. Regression model: log viral load = 7.69 − 1.01 × G3 − 0.7 × G1 + 0.002 × ALT − 0.86 × fatigue