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Ice formation and accumulation on surfaces can result in severe problems for solar photovoltaic installations, offshore oil platforms, wind turbines and aircrafts. In addition, blockage of pipelines by formation and accumulation of clathrate hydrates of natural gases has safety and economical concerns in oil and gas operations, particularly at high pressures and low temperatures such as those found in subsea or arctic environments. Practical adoption of icephobic/hydrate-phobic surfaces requires mechanical robustness and stability under harsh environments. Here, we develop durable and mechanically robust bilayer poly-divinylbenzene (pDVB)/poly-perfluorodecylacrylate (pPFDA) coatings using initiated chemical vapor deposition (iCVD) to reduce the adhesion strength of ice/hydrates to underlying substrates (silicon and steel). Utilizing a highly-cross-linked polymer (pDVB) underneath a very thin veneer of fluorine-rich polymer (pPFDA) we have designed inherently rough bilayer polymer films that can be deposited on rough steel substrates resulting in surfaces which exhibit a receding water contact angle (WCA) higher than 150° and WCA hysteresis as low as 4°. Optical profilometer measurements were performed on the films and root mean square (RMS) roughness values of Rq = 178.0 ± 17.5 nm and Rq = 312.7 ± 23.5 nm were obtained on silicon and steel substrates, respectively. When steel surfaces are coated with these smooth hard iCVD bilayer polymer films, the strength of ice adhesion is reduced from 1010 ± 95 kPa to 180 ± 85 kPa. The adhesion strength of the cyclopentane (CyC5) hydrate is also reduced from 220 ± 45 kPa on rough steel substrates to 34 ± 12 kPa on the polymer-coated steel substrates. The durability of these bilayer polymer coated icephobic and hydrate-phobic substrates is confirmed by sand erosion tests and examination of multiple ice/hydrate adhesion/de-adhesion cycles.

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The goal of this work is to provide an evaluation of the uncertainties in the calculation and measurement of erosion caused by solid particles that are entrained in the produced fluids in the oil and gas industry. Erosive damage is of great importance in production and transportation facilities, and it has been studied widely utilizing experiments or modeling approaches. The experimental setup used by researchers and uncertainty in determining the particle impact condition were key factors in the erosion measurement results and corresponding derived models. The effect of these parameters is studied in this work, and a guideline is provided to address the resulting error. In order to address the effect of particle velocity on erosion, Particle Image Velocimetry (PIV) is used and velocity distribution is obtained. The effect of particle velocity is analyzed in both experiments and erosion models. The erosion calculations by Det Norske Veritas (DNV) and Erosion/Corrosion Research Center (E/CRC) models have been compared to experimental data collected at the University of Tulsa and available data in the literature. A semimechanistic erosion equation which has been developed for some alloys that are being used extensively in the oil and gas industry is implemented in the CFD simulations. Based on the power-law dependency of erosion models on particle impact velocity, it is shown that uncertainty in the determination of particle velocity is propagating to the measured material losses in the experiments or in the predicted values in the erosion models. The erosion model predictions showed general agreement with experimental data in the literature for a wide range of conditions, but over predictions and under predictions have been observed which are due to the uncertainty in the measurements or erosion modeling.

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The oil produced from offshore reservoirs normally contains considerable amount of water. The separation of water from oil is very crucial in petroleum industry. Studying the coalescence of two droplets or one droplet and interface can lead to better understanding of oil-water separation process. In this study, the coalescence of two droplets and droplet-interface are simulated using a commercial Computational Fluid Dynamics (CFD) code FLUENT 14. In order to track the interface of two fluids, two approaches, Volume of Fluid (VOF) and Level-Set method were utilized. The results are compared with experimental measurements in literature and good agreement was observed. The effect of different parameters such as droplet velocities, interfacial tension, viscosity of the continuous phase and off-center collision on the coalescence time has been investigated. The results revealed that coalescence time decreases as the droplet velocities increase. Also, continuous phase with higher viscosities and lower water-oil interfacial tension, increase the coalescence time.