Chong Wen Tong

Influence of introducing various meteorological parameters to the Angstrom-Prescott model for estimation of global solar radiation

AbstractThis study aims to recognize that whether introducing various meteorological parameters to the Angström–Prescott (A–P) model eventuates in enhancing the precision of monthly mean global solar radiation estimation in cities of Bandar Abbas and Jask, situated in the south coast of Iran. To identify the significance of the average, maximum and minimum ambient temperatures, average and maximum relative humidity as well as water vapor and sea level pressures, seven models have been chosen from the literature. Using the long-term measured data and via statistical regression technique, the new regression coefficients have been developed for the original A–P model and the other seven nominated models. The models’ performances have been appraised via commonly utilized statistical indicators. The results indicated that the new models provided only minor improvements over the traditional A–P model; therefore, as more complexity is associated with introducing different meteorological parameters, their applications are not appealing practically. Making comparisons with the existing models developed using PSO (particle swarm optimization) technique demonstrated the superiority of the new established A–P models of this study; consequently, even without any improvement, the simple A–P models are indeed qualified for accurate estimation of global solar radiation in cities of Bandar Abbas and Jask and their neighboring.

Rheology and Temperature Dependency Study of Saraline-Based Super Lightweight Completion Fluid

One of the effective alternatives to minimize this perforation-induced formation damage is by application of underbalanced perforation. Fluid systems with very low density could be used to perforate reservoirs in underbalanced pressure conditions that virtually eliminate or minimize fluid invasion and damage along perforation tunnels. To respond in the need such fluid, Saraline-based super lightweight completion fluid (SLWCF) has been formulated from glass bubble, stabilizing and homogeneity agent. This paper focuses on a rheological and statistical evaluation of Saraline-based SLWCF and its effect on operating temperature. Eight rheological models, namely the Bingham plastic, Ostwald-de Waele, Herschel-Bulkley, Casson, Sisko, Robertson-Stiff, Heinz-Casson, and Mizrahi-Berk, were used to describe the rheological behavior of the fluid. Based on the results, rheology of the fluid was best represented by both the Sisko and the Mizrahi-Berk models. Furthermore, it is also found that the viscosity of Saraline-based SLWCF was more dependent to temperature changes at low shear rate. The Arrhenius activation energy for the fluid to flow was also found to be decreasing with shear rate and their relationship can be expressed with a power law equation.

Density and Viscosity Prediction of Super Lightweight Completion Fluid SLWCF at Reservoir Conditions

This paper presents the effect of reservoir conditions, specifically temperature and pressure, on the rheological behavior and density of super lightweight completion fluid (SLWCF) for underbalanced perforation. In this study, fluid’s density was measured at various temperatures and pressure ranging from 313.15 K to 393.15 K, and 0.1 MPa to 25 MPa, respectively. Meanwhile, fluid’s viscosity was measured at temperature between 298.15 K to 373.15 K, and pressure range of 0.1 MPa and 4.48 MPa. In order to understand the effect of reservoir conditions to the density and viscosity of the fluid, experimental data were fitted to several density-/viscosity-temperature-pressure models and then the generated results were statistically evaluated. Based on the results, it is observed that the Tait-like equation was able to satisfactorily express the relationship between the density, pressure and temperature. The predicted density values based on the Tait-like equation are also in good agreement with the regressed model results. For the case of fluid’s viscosity, it is found that both modified Mehrotra and Svrcek’s and Ghaderi’s equation were the best equation for viscosity prediction. Using these equations, it is statistically possible to predict the variation of fluid’s density and viscosity over the wide range of pressure and temperature. Furthermore, it is also found that the predicted density and viscosity values are very close to the experimental data with very low deviation. This confirmed the reliability and accuracy of the prediction. This paper provides a novel data prediction of rheology and density of Saraline-based SLWCF at reservoir conditions for the purpose of underbalanced perforation. This result is essential as a tool for field engineers to roughly estimate the density and viscoplasticity of completion fluids as they subjected to reservoir conditions.