Qiyu Huang

To address the lack of theoretical understanding regarding crude oil wall adhesion in non-metallic pipelines and to compare it with the behavior in metallic pipelines, this study investigates the wall adhesion behavior of crude oil in non-metallic pipelines using a self-developed, simulated stirred tank setup. The main factors influencing crude oil adhesion in non-metallic pipelines were identified, and the differences in adhesion behaviors across different pipeline materials were clarified. Additionally, the reasons behind these behavioral differences were explored through contact angle measurements and the interfacial energy theory. The results indicate that the factors affecting the transportation temperature of crude oil in non-metallic pipelines include the overall water content, shear strength, and wax content of crude oil. On average, the amount of adhered crude oil in the three types of non-metallic pipeline was lower than that in the metallic pipelines. Among them, the flexible, composite non-metallic pipeline showed the greatest reduction in average adhered oil mass by 22.86%. This significant reduction is attributed to the reduced adhesion of crude oil on the non-metallic surfaces. Therefore, using non-metallic pipelines in crude oil transportation networks is advantageous for implementing low-temperature gathering and transportation processes.

In our previous article (Gao et al. 2020), a mathematical model including elastic and yield components but not viscous component was developed to predict the wax plug transportation force. In this work, an analytical model was developed to calculate the wax plug transportation force, and the viscous component was introduced into the analytical model to capture some of the time effects. In this analytical model, the viscoelastic behavior of the wax deposit was characterized by a three-parameter model, formulated by adding an additional spring element to the Kelvin-Voight model. The Laplace transformation was used to solve the model. According to the calculated results of the analytical model, the transportation force of the wax plug was observed to slightly increase with time and then tended to level off. To obtain a parameter in the model and verify the model, the pigging experiments were conducted using foam pigs. During the pigging process of the foam pig, the wax plug transportation force in a five-phase wax removal profile was determined by taking the steady wax breaking force from the resistive force of the wax layer. Moreover, the linear increase of the wax plug transportation force per unit contact area with the shear strength of the wax layer was found, as described by the functional relationship in the analytical model. The interfacial lubrication coefficient calculated from the experimental data based on the analytical model is between the coefficient for diesel-prepared deposits and coefficient for oil-A-prepared deposits. Experimental verification results show that the average relative error of the model is 12.47%. Field implication was proposed to illustrate the application of the model and the formation condition of the wax blockage.

In the oil field production, carbon dioxide flooding technology has become increasingly common for high water-cut oilfields. It not only reduces carbon emissions, but also greatly improves the efficiency of oil production. In the process of oil field gathering and transportation, most high water-cut crude oil pipelines have achieved in non-heating transportation technique, which

Impingement jets are widely used in erosion investigation as it is easy to control impact angle and particle velocities in experiments. Additionally, fluid flow velocities and particle velocities near target walls are previously measured using Laser Doppler Velocimetry (LDV), Particle Image Velocimetry (PIV) and Particle Tracking Velocimetry (PTV). These experimental results are