A.R. Al-Hashmi

Parameters of Drag Reducing Polymers and Drag Reduction Performance in Single-Phase Water Flow:

This study presents experimental investigation about the effect of polymer parameters on the performance of the drag reducing polymers in single-phase water flowing in a horizontal pipe of 30.6 mm ID. Master solutions (1000 ppm) of ten high-molecular weight polymers were injected at different flow rates to achieve polymer concentrations in the range of 2–40 ppm in the test section. The drag reduction increased with polymer concentration up to 10 ppm, above which it reached a plateau value. While the drag reduction at the plateau value increases with polymer molecular weight, the maximum drag reduction was not affected by the increase in polymer charge density up to 13%. For instance, the maximum drag reduction for anionic polymers with molecular weight 6–8 million Da. and charge density between 5 and 13% was around 60%, which decreased to around 38% for the polymer with charge density of 25%. Ionic polymers provided more drag reduction than nonionic ones. The overall conclusion is that drag reduction depends on polymer ability to form intermolecular associations and/or its flexibility, which can be enhanced by increasing molecular weight, decreasing charge density, and selecting smaller side groups in the main polymer backbone.

Viscosity correlations for light Omani crude using artificial neural networks

Predicting the crude oil viscosity is very crucial to the oil industry. Accurate prediction of the viscosity will lead to a better design of an energy efficient transportation system and helps in determining the enhanced oil recovery method. There has been intensive work in generating viscosity empirical correlations for under-saturated, saturated and deal oil. Due to the rapid growth in computational capabilities, artificial neural networks (ANNs) are found to be a useful tool for the development of crude oil viscosity correlations. In this work, artificial neural networks (ANNs) model is developed to predict the viscosity of dead, saturated and under-saturated Omani crude oil. Detailed comparison was also made with 38 oil viscosity correlations using Omani crude oil viscosity database. Twelve of these correlations are for dead oil viscosity, 14 are for saturated oil viscosity and 12 for under-saturated oil viscosity. The oil viscosity data were collected from PVT reports. Statistical analysis and cross-plots showed that the ANN model outperformed the considered viscosity correlations.

Effect of Water-Soluble Drag-Reducing Polymer on Flow Patterns and Pressure Gradients of Oil/Water Flow in Horizontal and Upward-Inclined Pipes

Experimental investigations of flow patterns and pressure gradients of oil/water flow with and without drag-reducing polymer (DRP) were carried out in horizontal and upward-inclined acrylic pipe of ...

Transportation of heavy oils using polymer-stabilized oil-in-water emulsions

The increase in demand for crude oil and the depletion of light crude oil reserves have led to increase in the production of heavy crude oils. This has resulted in an interest in decreasing the pumping costs by techniques such as heating, dilution and/or mixing with water. Among the aforementioned methods, emulsification of heavy crude oil with water is the cheapest, and hence, optimizing its application has found increasing attention. This study uses one of the heavy crude oils in Oman to study the viscosity reduction achieved by emulsification with water at different oil fractions, temperatures, shear rates and salt content. Two chemicals were used to stabilize the emulsions, namely a nonionic surfactant and an anionic, high molecular weight polymer. It was found that viscosity reduction higher than 90% can be obtained through the creation of oil-in-water emulsions with oil content of less than 70%. Generally, it was found that there is no effect on the viscosity reduction obtainable from oil-in-water emulsions produced using the nonionic surfactant at shear rate up to 1620xa0s−1, temperature up to 80xa0°C and salt content up to 2.0xa0wt%. On the other hand, the viscosity reduction using water-in-oil emulsions at a temperature of 30xa0°C increases with surfactant concentration and shear rate. Also, the increase in salt content adversely affected the viscosity reduction obtained using water-in-oil emulsions. Moreover, it was possible to create oil-in-water emulsions with 60% oil content and viscosity reduction of around 100% in tap water using 100 and 1000xa0ppm polymer at all temperatures investigated. However, the use of 2.0xa0wt% salt resulted in lowering the viscosity reduction to 53 and 80% at 30 and 45xa0°C, respectively. This diverse effect of salt was almost neutralized at 60 and 80xa0°C resulting in viscosity reduction higher than 90%. The emulsions created using 3xa0wt% surfactant were generally stable for one week to a temperature of around 23xa0°C. The stability of oil-in-water emulsions with an oil content higher than 60% was not affected by the presence of salt. The emulsions prepared with an oil content of 60% in 100xa0ppm polymer were stable only for 1xa0h. However, the stability in water for these emulsions was greatly enhanced by increasing the viscosity of the continuous water phase by using 1000xa0ppm polymer, which resulted in stability higher than 70% after 24xa0h of incubation at 23xa0°C. The presence of 2.0xa0wt% salt in 1000xa0ppm polymer emulsions resulted in rendering these emulsions as instable even after 1xa0h of incubation. It can be concluded that high molecular weight polymers can find application in drag reduction for heavy crude oils after thoroughly investigating the effect of different polymer molecular parameters such as molecular weight and charge density.