CFD study and experimental validation of low liquid-loading flow assurance in oil and gas transport: studying the effect of fluid properties and operating conditions on flow variables.

Low liquid-loading flow frequently occurs during the transport of gas products in various industries, such as in the Oil & Gas, the Food, and the Pharmaceutical Industries. Even small amounts of liquid can have a significant effect on the flow conditions inside the pipeline, such as increased pressure loss, pipe wall stresses and corrosion, and liquid holdup along the pipeline. However, most studies that analyze this type of flow only use atmospheric pressures and horizontal 1-in or 2-in pipes, which do not accurately represent the range of operating conditions present in industrial applications. Therefore, this study focused on modeling low liquid-loading flow in medium-sized (6-10 in) pipes, using CFD simulations and experimental data from the University of Tulsa, and then applying it to real operating conditions from a Colombian gas pipeline. An acceptable difference was observed between experimental and CFD data, both for the liquid holdup (18%) and for the pressure drop (12%). Variables like pressure drop and wall shear stress increase with phase velocity, operating pressure, and pipe inclination. Liquid holdup increases with liquid velocity but decreases with all other factors. The relation of flow variables with phase velocities is of particular interest: Doubling the gas velocity decreased holdup 70% and increased pressure drop tenfold. On the other hand, the presence of the liquid phase seems to be more influential on process variables than its exact flowrate; the introduction of the liquid phase to a single-phase gas causes an increase in pressure loss by a factor of three, but doubling the liquid velocity only increases the pressure loss by a further 30%.

Asserting the pertinence of the interdependent use of seismic images and wireline logs in the evaluation of selected reservoirs in the Osland field, offshore Niger Delta, Nigeria.

This study presents a correct time and depth correlations with enhanced velocity analysis, based on two reservoir horizons mapped across two wells (Osl-1 and Osl-2). It involves the use of high-resolution images to delineate the complex geological structures associated with Reservoir A-horizon (R-Ah) and Reservoir B-horizon (R-Bh) based on 3-D seismic sections and wireline logs. It focuses on showcasing magnified images of the well to seismic tie (W-ST), to enhance appropriate times and depths posting to aid correct determination of the pay thicknesses (Pt), drainage areas (Ad) and the mapping of other probable areas within the hydrocarbon field. The idea is to magnify the points of interested at very close intervals (≤2 feet) to enable the mapping of the actual positions and times of events within the reservoirs. The aim is to enhance better results and confidence in the interpretation, as such, reduce the uncertainty regarding hydrocarbon viability and volume estimation. R-Ah is tracking below 9550 feet and 2.460 s in Osl-1. It is below 9510 feet at 2.450 s in Osl-2. Similarly, R-Bh is tracking below 10550 feet at 2.655 s in Osl-1 and below 10520 feet at 2.650 s in Osl-2. R-Ah is about 70 feet (21.34 m) thick across Ols-1 and Osl-2 while R-Bh is 70 feet (21.34 m) thick and 100 feet (30.48 m) in Osl-1 and Osl-2 respectively. In total, Ad is 172 acres (69.6 × 104 m2) for R-Ah and 206 acres (83.4 × 104 m2) for R-Bh while the Pt is 140 feet (42.67 m) for R-Ah and 170 feet (51.82 m) for R-Bh. Possible wellbore positions to aid future developmental activities could be within the south-east, south-west and north-west directions of Osl-1 and Osl-2. The field is viable with regards to hydrocarbon availability, and the use of high-resolution images has aided accurate evaluation of Pt and Ad, hence, increased the confidence in the results of the interpretation.

Could petroleum work as lubricant oil on slippery lubricated surfaces to prevent inorganic scaling?

The use of nucleation and growth inhibitors at offshore oil industry to avoid inorganic scaling could be replaced by both physical and chemical modifications at surfaces to prevent the scaling. In that way, the slippery lubricated surfaces have been showing promising results as scaling preventers, notably when the lubricants are perfluorinated oils, which are immiscible with almost every kind of compound. Nonetheless, the requirement of periodically refilling these lubricant oils is disadvantageous, especially when dealing with deep sea facilities. Using petroleum as the lubricant oil could skip the refilling step, since it is always present in the extraction medium. So, this work tests the effectiveness of petroleum as the lubricant oil in functionalized textured polyaniline applied as anti-scaling material in conditions that simulate the medium of offshore operation. As result, petroleum as lubricant oil presents effective anti-scaling capacity and works perfectly in slippery lubricated surfaces.

Supported ionic liquids as highly efficient and low-cost material for CO2/CH4 separation process.

Physical immobilization of ionic liquids (ILs) in solid materials appears as an interesting strategy for the development of new sorbents for CO2 separation from natural gas. In this work the effect of physical immobilization of two ionic liquids with different anions (bmim[Cl] and bmim[OAc]) on two mesoporous supports (commercial silica SBA-15 and silica extracted from rice husk) was evaluated for CO2 separation from natural gas by experimental determination of CO2 sorption, CO2/CH4 selectivity and sorption kinetics. Results showed that the pure supports present the greatest CO2 sorption capacity when compared to immobilized ILs. However, CO2 removal efficiency improves considerably in the CO2/CH4 mixture when ILs are immobilized in these supports. The best selectivity results were obtained for supports immobilized with the IL bmim[Cl] and values increased for SIL-Cl by 37% and SBA-Cl 51% when compared with their respective supports. The contribution of SIL-Cl (3.03 ± 0.12) to separation performance (CO2/CH4) is similar to SBA-Cl (3.29 ± 0.39). ILs supported also presented fast sorption kinetics when compared to pure ILs thus being an interesting alternative in the search for highly efficient and low-cost separation processes.

Influence of magnetic field on barium sulfate incrustation from aqueous solutions.

The formation of scales in the petroleum industry, such as those composed of calcium and barium sulfates, may reduce productivity since these sediments can partially or totally obstruct the pipes. The mitigation of these inorganic precipitates can be accomplished by using scale inhibitors or by non-intrusive physical technologies. Here, we investigated the influence of magnetic field on the incrustations of barium sulfate by analyzing the concentration of barium and sulfate ions, the solution flow rate, the capillary tube geometry, and the magnetic field intensity in a homemade experimental unit supported on the monitoring of the dynamic differential pressure. The results show that the saline concentration and the flow rate of the solutions and the geometry of the capillary tube have a significant influence on the dynamics of barium sulfate incrustation. The presence of the magnetic field tends to prolong the induction time of the barium sulfate precipitation. A semi-empirical model was used to describe the effect of the studied variables on the barium sulfate incrustation behavior. The X-ray diffraction data of the precipitated particles analyzed using the Rietveld method suggest that the use of the magnetic field favor the formation of more crystalline particles and with smaller crystallite size than those formed in the absence of a magnetic field. Optical and scanning electron microscopy measurements also corroborate with these findings. The results from this study suggest that magnetic fields can be of interest in practical crystallization processes of barium sulfate and successfully applied to decrease the speed of barium sulfate incrustation in pipelines.