Heavy Oil Transportation Research Articles

Study of a multifunctional composition in the preparation and transportation of heavy oils

Study of a multifunctional composition in the preparation and transportation of heavy oils

Insights into water-lubricated transport of heavy and extra-heavy oils: Application of CFD, RSM, and metaheuristic optimized machine learning models

With diminishing light crude oil reserves, the focus shifts to heavy and extra-heavy crude oil, posing challenges with high viscosity impeding flow. Water-lubricated technology addresses this issue in oil transmission lines. This study introduces a novel method integrating response surface methodology (RSM), computational fluid dynamics (CFD), and optimized machine learning (ML) models to analyze pipeline pressure gradients (PG) in oil–water two-phase flows downstream of T-junctions. The present study uses the D-optimal technique for simulation design to optimize CFD computational demands efficiently. This study breaks new ground by proposing a framework that leverages support vector machines (SVMs). The proposed framework incorporates metaheuristic optimization algorithms (genetic algorithm (GA) and particle swarm optimization (PSO)) to achieve superior PG prediction accuracy. The optimized ML models outperformed RSM models for predicting PG. Results indicated that oil-to-water viscosity ratio and oil inlet velocity significantly affect PG, followed by water inlet velocity and surface tension between phases. In contrast, the oil-to-water density ratio, oil entry angle at the T-junction, and wall contact angle have minimal impact. Furthermore, statistical metrics and visual comparison tools identified the PSO-optimized SVM model based on linear kernel function as the most effective (MAPE = 13.2 % and R = 0.9949). The hybrid methodology presented in this research holds significant promise for optimizing heavy oil transfer efficiency in applications involving water-lubricated technologies.

CFD simulation of the surface pumping of heavy crude oil in eastern Ecuador

The research addresses the study of heat exchange between heavy crude oil and the environment during surface pumping, specifically of a crude oil with an API gravity of 17.5, under the particular atmospheric conditions of Eastern Ecuador. The main objective of the study is to evaluate the temperature loss in a 50-meter segment of SCH-80 pipe, with a diameter of 4 inches, used for the transportation of heavy crude. This aims to understand how heavy crude loses temperature and to determine the convective coefficient, knowing that the heat loss from the fluid to the environment occurs mainly by convection. This is to determine what the temperature losses will be in longer pipe sections. For this purpose, a methodology using computational fluid dynamics (CFD) simulation was employed, a key tool for predicting the thermal behavior of crude in interaction with the environment. It was determined that the convective coefficient is 52 W/m2.K, and there is a temperature loss of 3.2 K in the 50-meter section. With this data, future research could evaluate potential heating technologies that facilitate the transport of heavy crude oil. This approach would allow for exploring innovative solutions to improve efficiency and effectiveness in managing heavy crude, facing one of the main challenges in its transport: managing its high viscosity

Study on the Flow Characteristics of Heavy Oil-Water Two-Phase Flow in the Horizontal Pipeline.

Aiming at the problem of transportation for heavy oil during the middle-later development stages of the Lvda oilfield, based on the self-developed design of a visual circulating flow experimental apparatus for heavy oil-water two-phase flow-the flow regime characteristics and corresponding drag properties of the two-phase flow of Lvda viscous oil, which is simulated by 500# industrial white oil and water in a horizontal pipeline are investigated experimentally. According to the Kelvin-Helmholtz instability theory, the flow pattern transition criteria from stratified flow to annular flow (AF) are proposed. The effects of 0.11-0.90 m/s oil superficial velocities, 0.06-1.49 m/s water superficial velocities, and 0.09-0.93 input water cuts on the drag reduction effect of different flow regimes are analyzed. The experimental results indicated that with the increase of mixing velocity and water volume fraction, stratified flow, AF, oil plug flow, and dispersed oil lump flow are successively observed in the horizontal heavy oil-water two-phase flow, in which AF is the main flow pattern. As the Froude number increases to 4.0, the input water volume fraction does not change any more and remains at about 10% of the total flow rate in the process of converting from stratified flow to AF. The four delivery approaches can archive the reduction of transportation resistance for heavy oil at different degrees, in which the transportation of heavy oil surrounded by a water ring has the best effect of drag reduction. At the optimal working conditions of 0.61 m/s oil superficial velocity, 0.07 m/s water superficial velocity, and 0.10 input water cut, the pressure drop of water annulus conveying for heavy oil is only 1/62.54 of that of separate transport for pure heavy oil under the same oil flow rate.

Removal mechanism of adhering heavy oil from pipeline wall in low-temperature flow

With the global emphasis on heavy oil development and increasing water content in Chinese oilfields, the low-temperature flow of heavy oil has been widely concerned. Integrating experiments and theoretical modeling, a hydrodynamic balance model for removing adhering heavy oil from pipeline wall was proposed to determine the temperature threshold for heavy oil transportation (adhesion temperature, AT). Two forms of heavy oil removal from pipeline wall were identified in the study: slide and lift-off. At low temperatures, the abrupt increase in wall-adhesion mass is primarily due to the inability of oil droplets to be removed through lift-off, but rather only through slide. Therefore, the temperature marking the transition from lift-off to slide is suggested as the AT criterion. Predicted AT values were in effective concordance with experimental values, with a maximum deviation of 3.78 °C. ATs for oilfields were predicted, and field cooling transportation tests showed no significant pressure drop increase, indicating the model's practical applicability. Additionally, the influence factors of the model were analyzed based on considerations of adhesion force and hydrodynamic removal force. This study aims to reduce heating energy consumption and carbon emissions during transportation under the premise of ensuring safe flow of high water-content heavy oil.

In-Situ and Ex-Situ Processes during Production, Transportation and Refinery of Heavy Oil

Heavy oil and natural bitumen are expected to be alternatives to the depleting conventional crude oil resources for the coming decades, mainly due to their sustainability, safety and huge number of reserves worldwide [...]

Reversible emulsification based on pH-responsive surfactant with dynamic imine bond

Efficient demulsification of emulsions is crucial in heavy oil transportation, interfacial reactions, and emulsion polymerization applications. Surfactants that are responsive to the environment have the ability to alter their surface activity in a dynamic manner. However, these types of surfactants typically require a significant amount of energy and may be less efficient. The present study involved the preparation of a surfactant with dynamic covalent bonding and pH-responsive property. This was achieved through the creation of dynamic imine bonds between decyloxybenzaldehyde (DOBA) and sodium 3-amino-1-propanesulfonate (AP) via a Schiff base reaction to synthesize dynamic covalent surfactant CB. The present study aimed to investigate the impact of various pH environments on the conversion rate and interfacial tension of surfactant CB. To achieve this objective, 1H NMR, FTIR, and IFT tests were conducted. The results confirmed the reversible conversion of the dynamic imine bond with pH. Furthermore, the dynamic imine bonded surfactant demonstrated the ability to complete at least three emulsification-breakage cycles. The present investigation introduces a novel approach for the synthesis of pH-responsive surfactants through the utilization of dynamic covalent bonds.

Evaluation and mechanisms of modified SiO2 and biosurfactant compound system for viscosity reduction of heavy oil

The development and preparation of viscosity reducers are important for the extraction and transportation of heavy oil. In this study, we investigated the viscosity reduction effect of SiO2 in terms of size and mass fraction. Then we modified SiO2 with salicylic acid (SA) and sodium 3-sulfobenzoate (SS) to obtain two types of modified SiO2: SiO2-SA and SiO2-SS. Through screening, SiO2-SS was compounded with the biosurfactant sapindus saponin (BSS) to prepare a high-efficiency viscosity reducer. When the mass fraction of BSS was 1 wt%, and the mass fraction of SiO2-SS was 0.5 wt%, the DVR could reach 87.6 %. X-ray diffraction and rheological experiments proved that this viscosity reducer could destroy the structure of heavy components in heavy oil to reduce the flow resistance. This investigation of the synergistic interaction between nanoparticles and biosurfactants may help the development of environmentally friendly viscosity reducers.

Analysis of Core Annular Flow Behavior of Water-Lubricated Heavy Crude Oil Transport

A possible method for fluid transportation of heavy oil through horizontal pipes is core annular flow (CAF), which is water-lubricated. In this study, a large eddy simulation (LES) and a sub-grid-scale (SGS) model are used to examine CAF. The behavior of heavy oil flow through turbulent CAF in horizontal pipes is numerically investigated. The Smagorinsky model is utilized to capture small-scale unstable turbulent flows. The transient flow of oil and water is first separated under the behavior of the core fluid. Two different conditions of the horizontal pipes, one with sudden expansion and the other with sudden contraction, are considered in the geometry to investigate the effects of different velocities of oil and water on the velocity distribution, pressure drop, and volume fraction. The model was created to predict the losses that occur due to fouling and wall friction. According to the model, increasing water flow can reduce fouling. Additionally, the water phase had an impact on the CAF’s behavior and pressure drop. Also, the increased stability in the CAF reduces the pressure drop to a level that is comparable to water flow. This study demonstrated that a very viscous fluid may be conveyed efficiently utilizing the CAF method.

Drag Reduction Related to Boundary Layer Control in Transportation of Heavy Crude Oil by Pipeline: A Review

Drag Reduction Related to Boundary Layer Control in Transportation of Heavy Crude Oil by Pipeline: A Review

An Experimental Study on the Influence of the Fractal Characteristics of X80 Steel Surface Morphology on Water Ring Stability

The surface morphology of X80 steel with hydrophilic underwater oleophobic characteristic is described greater comprehensively and quantitatively in this work by combining fractal dimension and multifractal. X80 steel with hydrophilic underwater oleophobic surface characteristics was constructed using a chemical etching method. Then, with the aid of three wettability parameters—contact angle, rolling angle, and adhesion work—this study investigated the relationship between the surface fractal dimension of X80 and the stability of the water ring in the core annular flow. The results showed that: (1) the fractal dimension of X80 steel specimens increased first and then decreased with the increase of reaction time. Besides that, the value of it was greater than 2, indicating that the surface had obvious fractal characteristics. The spectral difference, Δf(α), and the spectral width, Δα, supplemented the description of the X80 steel surface morphology, which was consistent with the scanning electron microscope results. (2) When the maximum fractal dimension was 2.0808, the minimum contact angle of distilled water on its surface was 50.2°, and the maximum contact angle of underwater oil droplets was 166.4°. The larger the fractal dimension of X80 steel with hydrophilic underwater oleophobic properties, the more hydrophilic and underwater oleophobic it is. This illustrated that there was a strong binding force between the water and the X80 steel pipe wall, and hence the quality and efficiency of the core annular flow was improved, which was more conducive to the promotion of this technology in the field of heavy oil transportation.

Synthesis of a non-polymeric surfactant from naturally occurring vegetable acid and its use as a viscosity modifier and asphaltene dispersant for heavy oil

The extraction and transportation of heavy oil, which accounts for a significant portion of the world's energy sources, often requires the use of various methods, including the use of chemicals. Surfactants have proven effective in this regard. Therefore, the present study focuses on the synthesis of a non-polymeric surfactant derived from naturally occurring vegetable acid. The synthesized surfactant is subsequently characterized using several analytical techniques, namely FTIR (Fourier Transform Infrared Spectroscopy), NMR (Nuclear Magnetic Resonance), TGA (Thermogravimetric Analysis), and elemental analysis. The surfactant demonstrated promising properties as a viscosity modifier and asphaltene dispersant for heavy crude oil samples. The results obtained at a concentration of 600 ppm were particularly favourable, with minimal improvements observed beyond this concentration. The analysis of asphaltene samples further supported the surfactant's effectiveness through hydrogen bonding and π-π interaction. UV–visible spectroscopy and relative viscosity measurements provided additional evidence of the surfactant's ability to disperse asphaltenes effectively.

Applications of drag reducers for the pipeline transportation of heavy crude oils: A critical review and future research directions

AbstractThe long‐distance pipeline transportation of heavy crudes demands optimal pumping procedures to abate overhead expenditures in the midstream phase. This can be facilitated by reducing both the oil viscosity and the frictional losses induced by the turbulent flow zone. The dualistic approach of reducing both viscosity and drag requires the optimization of several parameters such as concentrations and types of diluents and additives. This manuscript critically reviews various technologies being undertaken to facilitate the pipeline transportation of heavy crude oils by highlighting the technique of dilution coupled with the addition of drag reducing agents (DRA). DRA such as surfactants, nanoparticles, bio‐additives, polymers, and fibres are blended with the diluted crudes to suppress the proliferation of turbulent eddies which in turn assist in pumping the oil at a higher flow rate under constant pressure conditions. Several investigations have reported that drag reduction is significantly enhanced by varying the molecular structure of the DRA. In addition, an optimum flow rate coupled with a specific surfactant concentration at an ideal temperature can significantly reduce head losses and pumping expenditures. Further research is imperative to study the effect of the polymer structure with respect to the induced shear degradation and dissolution behavior of the crude.

Physico - Chemical Studies of Indian Crude Oil

Abstract: Crude oil is a complex mixture of non-metallic components like Sulphur, Nitrogen, Oxygen, and other elements with hydrocarbons. Crude oil is distinguished by several chemical and physical features that play an essential role in the oil industry. These qualities are critical in making decisions in the exploration and production of crude oil. Heavy crude oil is highly viscous crude oil with high Asphaltene content and API in the range of 10-25. Especially, transportation of Heavy Crude oil is herculean task for Petroleum industry. As a result, the study of physical and chemical properties becomes crucial for the petroleum industry. The current work deals with the investigation of physico-chemical characteristics of Indian crude oil.

Dissipative particle dynamics to study asphaltenes and surfactants interactions at the oil–water interface

Heavy oil is an important unconventional oil resource, but its high viscosity and complex composition make them difficult to transport. Heavy oil-in-water emulsion transportation is considered to be one of the most effective methods. Asphaltenes in crude oil is a natural surfactant that is responsible for the stability of the emulsions. It is necessary to better understand the influence of asphaltenes and surfactants on the stability of the oil–water interface during the transportation of heavy oil. Although several studies have been carried out on the properties of asphaltenes at the oil–water interface, the scientific understanding of asphaltenes in reducing the interfacial tension (IFT) is still limited in terms of simulation studies. In this paper, asphaltenes were extracted and characterized, and the molecular structure of asphaltenes was constructed. Dissipative particle dynamics (DPD) simulations are employed to study the distributions and interfacial behaviors of asphaltenes and surfactants in oil–water systems. The coarse-grained model of asphaltenes is constructed from basic structural fragments in the simulations, which is based on the inferred average molecular structure of asphaltenes. The results show that asphaltenes diffuse to the oil–water interface spontaneously and adsorb at the interface to form an interfacial film, which could reduce the IFT. However, the IFT is not controlled by the volume concentration of asphaltenes, but is directly related to the interfacial concentration. The IFT value of the oil–water system decreases by up to approximately 8 mN/m at an asphaltene concentration of 133 mM. In addition, the interfacial film formed by the synergistic adsorption of surfactants and asphaltenes has a tighter configuration, which further reduces the IFT and enhances the stability of emulsions. Moreover, the effect of surfactant head length on IFT of the oil–water interface was investigated in this study. The outcomes from this paper can help for a better understanding of asphaltenes and surfactants in stabilizing the oil–water interface and provide useful information for heavy oil transportation.

Rheological characterization and shear viscosity prediction of heavy oil-in-water emulsions

The rheology of oil-in-water emulsion is a key issues in heavy oil development, storage, transport, and processing. Based on single-factor experiments, the effect of shear rate (γ), dispersed-phase volume fraction (φ), continuous-phase viscosity (ηc), and droplet size (D50) on the rheological properties of heavy oil-in-water emulsions were evaluated through microscopic observation and rheological experiments. Furthermore, a 10-factor/3-level experiment was designed to investigate the sensitive factors affecting shear viscosity. The experimental results indicated that, when the volume fraction of dispersed-phase was higher than 0.3, the rheological characteristics of the prepared emulsions exhibited an obvious shear-thinning behavior, and the droplet size had a significant influence on shear viscosity at shear rates between 0.3 and 100 s−1. When the volume fraction of the dispersed-phase was less than 0.3, the emulsions behaved as Newtonian liquids. As the shear rates increase, the droplets disperse to a greater extent, leading a reduction in viscosity, and ultimately causing the emulsion to exhibit the characteristics of a Newtonian fluid. Owing to the strong hydration effect of small droplets, the viscosity of small droplet-size emulsions increases at a constant dispersed-phase volume fraction. Emulsions exhibit obvious shear-thinning behavior with an increase in shear rate, as a result of a low effective dispersed-phase volume fraction under a high shear rate. Finally, the volume coefficient of the Sibree model was corrected by considering correlation factors from the experiments, and the Sibree model was improved. The improved shear viscosity model better fits the experimental data for all the studied heavy oil-in-water emulsion, with the mean relative error of 9.3%. Therefore, the improved model can predict the effects of all factors affecting shear viscosity.

Self‐assembly of surfactin‐like polymer in solution by the dissipative particle dynamics method

AbstractSurfactin is a kind of special and efficient cyclic lipopeptide biosurfactant, which is composed of a seven‐peptide ring and a fatty acid tail chain and is widely used in the fields of medicine, environmental remediation and heavy oil transportation. This special ring structure also makes surfactin have great application potential in biomedicine and surface catalysis. In this work, the self‐assembly behavior of surfactin‐like polymer in selective solvents was studied by dissipative particle dynamics. By changing the interaction parameters, the size of the hydrophilic ring, the length of the hydrophobic tail chain and the concentration, a series of structures such as vesicles, disk‐like micelles, worm‐like micelles, sphere‐like micelles and ring‐like micelles were obtained from the establishment of the phase diagram. We explored the dynamic formation paths of vesicles and ring‐like micelles and discovered morphological changes during their aggregation. The mechanism of sphere‐like micelle formation at lower concentration was also studied, explained by the packing of molecules of effective conical shape. The structural properties of the vesicles were also intensively studied. Based on the special ring structure of surfactin‐like polymers, we explored the difference in their self‐assembly behavior from those of linear block copolymers and giant surfactant‐like polymers. A detailed study on the self‐assembly of surfactin‐like polymer can deepen the understanding of ordered aggregates of cyclic surfactants in selective solvents and can drive important implications for their practical application. © 2023 Society of Industrial Chemistry.

Review of Core Annular Flow

With the increasing demand for heavy oil, core annular flow (CAF) is an economical method to transport heavy oil, and many researchers have explored the energy-saving aspects of the CAF method. This paper presents a review of CAF energy saving and factors affecting CAF energy saving. Among them, the energy saving of CAF mainly concerns the changes in pressure drop and drag reduction efficiency; the factors affecting the energy saving of CAF mainly concern the problem of stability, the issue of restarting the pipeline system, the impact of a nozzle, the impact of fouling on the flow in the pipe, and the problem of oil–water accumulation. The aim of this paper is to provide a reference for the practical application of CAF in heavy oil transportation.

Biosurfactants as Multifunctional Remediation Agents of Environmental Pollutants Generated by the Petroleum Industry

Fuel and oil spills during the exploration, refining, and distribution of oil and petrochemicals are primarily responsible for the accumulation of organic pollutants in the environment. The reduction in contamination caused by hydrocarbons, heavy metals, oily effluents, and particulate matter generated by industrial activities and the efficient recovery of oil at great depths in an environmentally friendly way pose a challenge, as recovery and cleaning processes require the direct application of surface-active agents, detergents, degreasers, or solvents, often generating other environmental problems due to the toxicity and accumulation of these substances. Thus, the application of natural surface-active agents is an attractive solution. Due to their amphipathic structures, microbial surfactants solubilize oil through the formation of small aggregates (micelles) that disperse in water, with numerous applications in the petroleum industry. Biosurfactants have proven their usefulness in solubilizing oil trapped in rock, which is a prerequisite for enhanced oil recovery (EOR). Biosurfactants are also important biotechnological agents in anti-corrosion processes, preventing incrustations and the formation of biofilms on metallic surfaces, and are used in formulations of emulsifiers/demulsifiers, facilitate the transport of heavy oil through pipelines, and have other innovative applications in the oil industry. The use of natural surfactants can reduce the generation of pollutants from the use of synthetic detergents or chemical solvents without sacrificing economic gains for the oil industry. Therefore, investments in biotechnological processes are essential. It is predicted that, in the not-too-distant future, natural surfactants will become viable from an economic standpoint and dominate the world market. The application of biosurfactants in these settings would lead to industrial growth and environmental sustainability. The main goal of this paper is to provide an overview of diverse applications of biosurfactants on environmental remediation, petroleum biotechnology, and the oil industry through a scientific literature review.

Preparation of Temperature-Sensitive SiO2–PSBMA for Reducing the Viscosity of Heavy Oil

Viscosity reduction by emulsification is one of the most effective methods for the recovery of heavy oil. Nanoparticles with low toxicity and low cost can stabilize oil-in-water (O/W) Pickering emulsions to reduce the viscosity of heavy oil and thereby have become a new type of emulsifier in recent years. The stimuli-responsive emulsions formed by responsive particles can achieve emulsification and demulsification under external stimuli, providing convenient conditions for heavy oil transportation and recovery, where the temperature response is easier to achieve. In this study, six groups of temperature-sensitive SiO2–PSBMA (PSBMA: polysulfobetaine methacrylate) with different particle sizes were prepared by the reverse atom transfer radical polymerization (RATRP) method. The morphologies of SiO2 particles before and after grafting were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and atomic force microscopy (AFM), and the structure of the product was characterized by Fourier transform infrared (FT-IR) spectroscopy, which showed that PSBMA was successfully grafted to SiO2. The grafting ratios (η) of six groups of SiO2–PSBMA measured by thermogravimetric analysis (TGA) were similar (34.50–42.94%). The temperature sensitivity of SiO2–PSBMA was determined by dynamic light scattering (DLS) and the contact angles at different temperatures, which showed that its upper critical solution temperature (UCST) was about 40–50 °C. SiO2–PSBMA was applied to GD2 heavy oil to reduce the viscosity at 60 °C, which showed that the SiO2–PSBMA had a good emulsification effect. With the increase of particle size, the viscosity reduction rate (VRR) showed a trend of first increase and then decrease. The highest VRR was 96.41%, achieved by 227.61 nm SiO2–PSBMA. All of the emulsions stabilized by SiO2–PSBMA were able to demulsify at room temperature. It can be used as an intelligent temperature-responsive viscosity reducer for heavy oil to control emulsions on demand.