The thermodynamic and kinetic hydrates inhibition effects of addition of synergents poly(ethylene oxide) (PEO) and vinyl caprolactum (VCAP) with ionic liquids 1-methyl-1-propylpyrrolidinium chloride [PMPy][Cl] and... more
The thermodynamic and kinetic hydrates inhibition effects of addition of synergents poly(ethylene oxide) (PEO) and vinyl caprolactum (VCAP) with ionic liquids 1-methyl-1-propylpyrrolidinium chloride [PMPy][Cl] and 1-methyl-1-propylpyrrolidinium triflate [PMPy][triflate] were studied on a synthetic quaternary gas mixture (methane, C 1 = 84.20%; ethane, C 2 = 9.90%; n-hexane, C 6+ = 0.015%; CO 2 = 2.46%; N 2 = 2.19%). The results show that the addition of synergents with ionic liquids helps to improve their thermodynamic and kinetic hydrate inhibition effectiveness simultaneously.
Asphaltene precipitation and deposition have been a formation damage problem for decades, with the most devastating effects being wettability alteration and permeability impairment. To this effect, a critical look into the laboratory... more
Asphaltene precipitation and deposition have been a formation damage problem for decades, with the most devastating effects being wettability alteration and permeability impairment. To this effect, a critical look into the laboratory studies and models developed to quantify/predict permeability and wettability alterations are reviewed, stating their assumptions and limitations. For wettability alterations, the mechanism is predominantly surface adsorption, which is controlled by the asphaltene contacting minerals as they control the surface chemistry, charge, and electrochemical interactions. The most promising wettability alteration evaluation techniques are nuclear magnetic resonance, ζ potential, and the use of high-resolution microscopy. The integration of such techniques, which is still missing, would reinforce the understanding of asphaltene interaction with rock minerals (especially clays), which holds the key to developing a strategy for modeling wettability alteration. With regard to permeability impairment, surface deposition, pore plugging, and fine migration have been identified as the dominant mechanisms with several models reporting the simultaneous existence of multiple mechanisms. Existing experimental findings showed that asphaltene deposition is non-uniform due to mineral distribution which further complicates the modeling process. It also remains a challenge to separate changes due to adsorption (wettability changes) from those due to pore size reduction (permeability impairment).
Iran has the second largest natural gas reserves in the world. Therefore, it is heavily investing in expanding its gas production, processing, and transportation capacity. The main objectives include: Promoting the usage of natural gas as... more
Iran has the second largest natural gas reserves in the world. Therefore, it is heavily investing in expanding its gas production, processing, and transportation capacity. The main objectives include: Promoting the usage of natural gas as a low carbon fuel and primary source of energy to reduce the domestic demand on oil. Using natural gas for EOR and pressure maintenance in mature oil fields. Exporting natural gas and its products. However, expanding the natural gas network demands a more comprehensive research on potential gas hydrate problems and mitigation techniques. In this communication, we give a review on typical gas hydrate problems in the Iranian production and gas transportation facilities and networks and various prevention techniques. We also present details of construction and commissioning of a hydrate test rig at the Research Institute of Petroleum Industry (RIPI) of the National Iranian Oil Company (NIOC). Finally, we present experimental data on the hydrate stability zone of some Iranian natural gases. We conclude that further national and international research and investment is beneficial to minimize gas hydrate risks in the Iranian Gas Industries, as well as exploring positive applications of gas hydrates with respect to specific conditions in Iran.
The enormous cost of handling the challenges of flow assurance in subsea wells, flowlines, and risers, especially in deepwater applications, has necessitated a proactive approach to prevent their risk of occurrence. To ensure that... more
The enormous cost of handling the challenges of flow assurance in subsea wells, flowlines, and risers, especially in deepwater applications, has necessitated a proactive approach to prevent their risk of occurrence. To ensure that transportation of the hydrocarbon is economical and efficient from the subsea wellhead to the processing units, a flow assurance heat management system is relevant in the design and planning of a fluid transport system. Consequently, the advancement of new technologies to serve the increasing need by exploring the technologically challenging and hostile subsea fields is of great importance. A comparative study on heat management systems in flowlines was conducted from the top five publishers (Elsevier, Springer, Taylor & Francis, Wiley, and Sage) based on the number of publications to determine the level of work done by researchers in the last decade, the figures from the study showed the need for scientific research in the field of active heating. Additionally, a review was implemented to ascertain the likely advantages and drawbacks of each technique, its limitations concerning field applications and then recommend suitable cost-effective technique(s). The active heating system gives the most cost-effective solution for subsea deepwater fields.
Wax or paraffin formation in subsea pipelines is a major problem in the upstream petroleum industry, accounting for tremendous economic losses. Researchers have reported that approximately 85% of the world's oils encounter problems from... more
Wax or paraffin formation in subsea pipelines is a major problem in the upstream petroleum industry, accounting for tremendous economic losses. Researchers have reported that approximately 85% of the world's oils encounter problems from wax formation (Thota and Onyeanuna 2016). In this manuscript, the authors briefly discuss the mechanism of wax formation in pipelines. Next, a review of various wax-mitigation technologies is provided. The review includes citations of various thermal, chemical, mechanical, biological, and other innovative methods reported by previous researchers and used in the industry.
In the present day of increasing hydrocarbon demand, the direction of oil exploration has moved to ever increasing offshore depths and more remote land masses with harsher environments. To this end, our industry has to adapt to the... more
In the present day of increasing hydrocarbon demand, the direction of oil exploration has moved to ever increasing
offshore depths and more remote land masses with harsher environments. To this end, our industry has to adapt to
the increasing challenges that have to be faced to ensure that these hydrocarbons can still be economically
recovered. The flow assurance strategies that are currently being deployed to achieve successful hydrocarbons
recovery from these increasing technically challenged areas, increasingly demand an integrated approach to the
design of the transportation systems. It is no longer the case that each element of a hydrocarbon development can
be designed in isolation.
Flow Assurance is not just an analytical routine to predict the pressure and temperature profiles of single and multiphase
pipelines, but an advanced tool-set that models the flow of hydrocarbons from the well bore all the way to
the process facilities and beyond. The tools now used in Flow Assurance have improved the engineer‟s insight into
the critical parameters to the point where informed design improvements can be made that could not previously
have been justified.
The paper will consider the problems faced by today‟s ever more extreme transportation requirements, review
current advanced methodologies for flow assurance for transportation systems and show how integration of flow
assurance into systems design vastly improves and in some case enables hydrocarbon developments.
Observations will be provided in the form of three short case presentations that have implemented advanced
techniques to achieve robust solutions. Specifically:
Flow assurance issues and implications for ultra deep transportation pipelines
Planning for the removal of hydrates from wet gas field developments
Understanding Carbon Capture and Storage transportation systems
Hydraulic performance and thermal characterization are the main parameters dictating proper consideration of flow assurance in pipelines. Hydraulic performance considers the evaluation of multiphase systems, specifically the equilibrium... more
Hydraulic performance and thermal characterization are the main parameters dictating proper consideration of flow assurance in pipelines. Hydraulic performance considers the evaluation of multiphase systems, specifically the equilibrium of phases and consequent flow patterns and their impact on pressure loss, holdup and sustainable and safe flow transport characteristics. Secure supply of hydrocarbons via pipelines plays crucial importance to maximize their production. In this study, a multiphase flow simulation of gas-condensate is developed using PIPESIM™ software. The data and main physical parameters correspond to a projected off-shore natural gas pipeline located in the north sea of Venezuela. The flow of hydrocarbons is analyzed and potential improvements are presented using both a traditional single-size and an ¨out-of-the-box¨ multi-sizing technique with the objective to reduce predicted overall holdups and pressure drops along the pipeline. The simulation permitted to asses...
Oil and Gas Hydrate plug dissociation in subsea pipelines is a challenging problem in oil and gas transport systems as limited options are available for remediation. Key concerns include technical, operational deferment and safety... more
Oil and Gas Hydrate plug dissociation in subsea pipelines is a challenging problem in oil and gas transport systems as limited options are available for remediation. Key concerns include technical, operational deferment and safety hazards that are associated with hydrate plug dissociation in oil and gas pipelines. This paper presents a comprehensive review of the physics of hydrate plugs remediation including a compilation of dissociation models, experimental work performed to date, and a detailed analysis on the problem of gas hydrate from a flow assurance perspective. Depressurization methods are critically reviewed, with influence of temperature, pressure, velocity and hydrate plug properties discussed with detail. Outstanding research questions for hydrate plug dissociation highlighted.
Over the years, the desire of oil and gas operators to reduce topside facilities using Subsea Production Systems (SPS) has increased tremendously. This has resulted in the overwhelming importance of flowassurance studies in ensuring the... more
Over the years, the desire of oil and gas operators to reduce topside facilities using Subsea Production Systems (SPS) has increased tremendously. This has resulted in the overwhelming importance of flowassurance studies in ensuring the SPS delivers the produced fluid to the production platform at thedesired operating conditions for surface facilities while still meeting the production ambition of the oiland gas operator. This paper will illustrate how flow assurance management and benchmarking forslugging, hydrate and wax formation was achieved for an offshore oil field. Furthermore, it concludesby recommending operational modes which should be addressed prior to finalising the pipeline architecture by proposing possible approaches to maximizing production for the field under study.
Subsea development has in later times become more and more popular. By the use of subsea production and processing structures situated on the seafloor, the hydrocarbons from multiple producing wells are combined and brought to storage... more
Subsea development has in later times become more and more popular. By the use of subsea production and processing structures situated on the seafloor, the hydrocarbons from multiple producing wells are combined and brought to storage facilities either at surface, or onshore. This reduces the need of production rigs and ultimately reduces the cost. In this paper, some of the main subjects involving subsea development are explained. The introduction of some design elements in a hypothetical subsea development has also been chosen and explained in this paper.
The enormous cost of handling the challenges of flow assurance in subsea wells, flowlines, and risers, especially in deepwater applications, has necessitated a proactive approach to prevent their risk of occurrence. To ensure that... more
The enormous cost of handling the challenges of flow assurance in subsea wells, flowlines, and risers, especially in deepwater applications, has necessitated a proactive approach to prevent their risk of occurrence. To ensure that transportation of the hydrocarbon is economical and efficient from the subsea wellhead to the processing units, a flow assurance heat management system is relevant in the design and planning of a fluid transport system. Consequently, the advancement of new technologies to serve the increasing need by exploring the technologically challenging and hostile subsea fields is of great importance. A comparative study on heat management systems in flowlines was conducted from the top five publishers (Elsevier, Springer, Taylor & Francis, Wiley, and Sage) based on the number of publications to determine the level of work done by researchers in the last decade, the figures from the study showed the need for scientific research in the field of active heating. Additio...
Hydraulic performance and thermal characterization are the main parameters dictating proper consideration of flow assurance in pipelines. Hydraulic performance considers the evaluation of multiphase systems, specifically the equilibrium... more
Hydraulic performance and thermal characterization are the main parameters dictating proper consideration of flow assurance in pipelines. Hydraulic performance considers the evaluation of multiphase systems, specifically the equilibrium of phases and consequent flow patterns and their impact on pressure loss, holdup and sustainable and safe flow transport characteristics. Secure supply of hydrocarbons via pipelines plays crucial importance to maximize their production. In this study, a multiphase flow simulation of gas-condensate is developed using PIPESIM TM software. The data and main physical parameters correspond to a projected offshore natural gas pipeline located in the north sea of Venezuela. The flow of hydrocarbons is analyzed and potential improvements are presented using both a traditional single-size and an¨out-of-the-box¨multi-sizing technique with the objective to reduce predicted overall holdups and pressure drops along the pipeline. The simulation permitted to assess different flow characteristics as liquid holdup, flow rate and pressure drop through different sections and accessories of the pipeline. Fixed pipeline insulation was maintained along all the study to keep a practical number of independent variables. The outcome of the analysis demonstrates that with a reasonable adjustment of pipe diameter, it is possible to increase the gas production without extra energy to compress the line, favoring the project economy and reducing its carbon footprint.
La investigación aquí desarrollada consiste en la utilización de la Dinámica de Fluidos Computacional (CFD) para el análisis del comportamiento de un flujo disperso de partículas dentro de una fase continua líquida en tuberías... more
La investigación aquí desarrollada consiste en la utilización de la Dinámica de Fluidos Computacional (CFD) para el análisis del comportamiento de un flujo disperso de partículas dentro de una fase continua líquida en tuberías horizontales. Las simulaciones se realizaron con el programa comercial ANSYS-Fluent con aplicación en dinámica de fluidos, basado en el método de los volúmenes finitos, utilizando modelaje Euleriano-Euleriano para el tratamiento bifásico (líquido-partículas), y un modelo de clausura para la fase sólida (partículas) basado en la Teoría Cinética Granular (TCG).
El principal objetivo del trabajo ha sido profundizar en la comprensión del flujo en regímenes heterogéneo y de saltación o lecho móvil, tomando en consideración la contribución del término cinético-colisional y friccional dentro del tensor de esfuerzos de la fase sólida, de acuerdo a la TCG. Además, se consideró en lo posible, el modelaje de las fuerzas de sustentación en la interacción partícula-fluido.
Los fluidos que componen el flujo bifásico analizado en las simulaciones son agua y arena, en un amplio rango de fracciones volumétricas, velocidades del flujo y diámetros de partículas. Se obtuvieron los perfiles de concentración de partículas dentro de la sección trasversal de la tubería en condiciones de flujo estacionario. Los resultados numéricos fueron comparados con datos experimentales obtenidos de fuentes confiables.
De esta forma, se determinó una configuración adecuada del modelo TCG, no encontrada previamente, que permitirá utilizar tal modelo dentro del análisis CFD de sistemas industriales relacionados con flujos partículas-fluido, tales como los encontrados, por ejemplo, en separadores de arena en tareas de producción y transporte de petróleo.
The present study investigated the wax deposition tendencies of a light Malaysian crude oil (42.4° API), and the wax inhibiting potential of some surfactants and their blends with nanoparticles. With the knowledge that the majority of the... more
The present study investigated the wax deposition tendencies of a light Malaysian crude oil (42.4° API), and the wax inhibiting potential of some surfactants and their blends with nanoparticles. With the knowledge that the majority of the wax inhibition research revolved around polymeric wax inhibitors, which cause environmental issues, we highlighted the potential of surfactants and their blend with SiO 2 nanoparticles as wax deposition inhibitors. Different surfactants including oil-based, silane-based, Gemini and bio-surfactants were considered as primary surfactants. The primary surfactants and their respective blends at a concentration of 400 ppm were screened as wax inhibitor candidates using cold finger apparatus. The screening results showed a significant influence on the paraffin inhibition efficiency on wax deposition by using 400 ppm of silane-based surfactant, which decreased the wax deposition up to 53.9% as compared to that of the untreated crude oil. The inhibition efficiency among the silane-based surfactant (highest) and bio-surfactant (lowest) revealed an appreciable difference up to 36.5%. Furthermore, the wax from the treated sample was found to deposit in a thin gel-like form, which adhered inadequately to the surface of the cold finger. A further investigation by blending the 400 ppm silane-based surfactant with a 400 ppm SiO 2 nanoparticle suspension in a load ratio of 3:1 found that the wax inhibition decreased up to 81% as compared to the scenario when they were not added. However, we have shown that the synergy between the silane-based surfactant and the nanoparticles is influenced by the concentration and load ratio of surfactant and nanoparticles, residence time, differential temperature and rotation rate.
In the petroleum industry, still a major problem is the deposition of paraffin wax especially during exploitation in Deepwater field. This study is aimed at characterizing crude oil sample, understanding the characteristic of paraffin wax... more
In the petroleum industry, still a major problem is the deposition of paraffin wax especially during exploitation in Deepwater field. This study is aimed at characterizing crude oil sample, understanding the characteristic of paraffin wax and testing the solubility of the precipitated wax in xylene and kerosene at different blend ratios. The crude oil sample which was obtained from Eleme community in Niger Delta, Nigeria, was characterized and the cloud point and pour point were obtained as 20 o C and 12 o C respectively. Results obtained from the solubility test shows that 100% Xylene dissolves 99.4% of the precipitated wax in 150 min and 90.1 % in 90 min. While for same quantity 100% kerosene shows solubility of 35.4% in 150 min and 26.2% in 90 min which implies that xylene although expensive is a better solvent for paraffin wax cleanup when compared to kerosene. At different xylene-kerosene blend ratios, the blend of 70:30%, Xylene: Kerosene mixture also gave an excellent result, far from the one obtainable in the 50:50%, and in very close proximity with the 80:20% blend. This indicates that Kerosene which is cheap and readily available when blended with xylene, an excellent solvent can be used on an industrial scale for the cleanup or dissolution of wax deposit in a cost effective and efficient manner.
This project report details about the design of a production well in an off-shore production field with optimal production rate. Using PIPESIM, a production well was designed with casing, tubing, downhole equipment(Packer) and completion,... more
This project report details about the design of a production well in an off-shore production field with optimal production rate. Using PIPESIM, a production well was designed with casing, tubing, downhole equipment(Packer) and completion, in accordance with the given data in the question. By fixing nodal point at the bottom hole of the well, nodal analysis was conducted using IPR model as Vogel’s model, which has given the production-system graph i.e, graph of pressure at the nodal point versus the stock tank liquid rate at the nodal analysis point. Using this graph, absolute open flow potential(AOFP) was found, which further helped to calculate the productivity index(PI) of the well. Inflow and outflow performance curves at various Gas Liquid ratio’s(GLR) were plotted by doing nodal analysis at the bottom hole of the production well, which has given the operating points of well at different GLR’s. Optimal production rate was obtained by conducting system analysis and it is the GLR giving maximum flow rate. By assuming the composition of the liquid flow in the well as methane or hydrogen sulfide, check for hydrate formation was also carried out.
Pipes that make up oil and gas wells are not vertical but could be inclined at any angle between the vertical and the horizontal which is a significant technology of modern drilling. Hence, this study has been undertaken to look at the... more
Pipes that make up oil and gas wells are not vertical but could be inclined at any angle between the vertical and the horizontal which is a significant technology of modern drilling. Hence, this study has been undertaken to look at the effect of inclination on flow characteristics especially at 10 degrees from both horizontal and vertical. Air/silicone oil flows in a 67 mm slightly deviated pipe have been investigated using advanced instrumentation: Wire Mesh Sensor Tomography (WMS) and Electrical Capacitance Tomography (ECT). They provide time and cross-sectionally resolved data on void fraction. Both the ECT probes and WMS were mounted on the inclined pipes upstream just at the point where flows were fully developed. By keeping the liquid flow rate constant at 10 litres/min (or liquid superficial velocity of 0.052m/s), gas flow rate was varied from 10 litres/min to 1000 litres/min (or gas superficial velocity from 0.05m/s to 4.7m/s). Then other values of liquid superficial velocity were considered. Visual observations were considered. Time series and void fraction were then measured for WMS while time series and liquid holdup were measured for ECT. The raw data were processed and then interpreted for proper analysis. From an analysis of the output from the tomography equipment, flow patterns were identified using both the reconstructed images as well as the characteristic signatures of Probability Density Function (PDF) plots of the time series of cross-sectionally averaged void fraction as suggested by some authors. Bubbly, slug and churn flows were observed for 10° from vertical pipe while bubbly, plug as well as slug flow when the pipe was inclined at 10° from horizontal. Examples of the PDFs are well illustrated which compares the use of ECT with WMS. In addition, statistical data such as Power Spectral Density (PSD), dominant frequency, mean void fraction as well as the structure velocities from cross correlation of the two planes of ECT have been identified.
The reservoir rock is made up of different minerals and its surface chemistry is influenced by the reservoir environment. Well operations implemented during the life of a field induce changes in the reservoir environment (pH) that affect... more
The reservoir rock is made up of different minerals and its surface chemistry is influenced by the reservoir environment. Well operations implemented during the life of a field induce changes in the reservoir environment (pH) that affect the minerals, resulting in a change of their surface chemistry. These changes result in wettability alterations, which have a significant effect on the overall production. Thus, this research provides insight into the behavior of calcite, feldspar, barite, dolomite, quartz, and sand in varying pH environments to ascertain the effect of pH change on mineral surface charge. This study employed ζ-potential measurements as a measure of the wettability alteration. The findings reveal that these rock minerals have their charge development controlled by mineral dissolution, ionic specie adsorption, and double-layer compression. Furthermore, the rock contacting mineral is critical in the wettability alteration, and an understanding of the effect of well operations on rock surface chemistry is critical.
Under near-gelling conditions, the precipitated wax particles can settle down due to gravity and form a bed at the bottom of the pipeline. During restart, the settled waxy bed can increase the pressure drop significantly, and the... more
Under near-gelling conditions, the precipitated wax particles can settle down due to gravity and form a bed at the bottom of the pipeline. During restart, the settled waxy bed can increase the pressure drop significantly, and the necessity for pigging and/or addition of chemicals has to be determined to re-entrain settled wax particles. A laboratory-scale flow loop, first of its kind, has been built and used to understand the settling and re-entrainment behavior. The experimental results confirmed the settling of precipitated wax in a pipe under quiescent conditions when the oil temperature falls between wax appearance temperature and pour point. During restart, complete re-entrainment was attained after reaching a critical flow rate. Solid transport models were able to predict reasonably good results in agreement with experiments. This work emphasizes the importance of understanding the behavior of waxy crude oil during production shutdown and design appropriate startup strategies.
Summary Wax or paraffin formation in subsea pipelines is a major problem in the upstream petroleum industry, accounting for tremendous economic losses. Researchers have reported that approximately 85% of the world's oils encounter... more
Summary Wax or paraffin formation in subsea pipelines is a major problem in the upstream petroleum industry, accounting for tremendous economic losses. Researchers have reported that approximately 85% of the world's oils encounter problems from wax formation (Thota and Onyeanuna 2016). In this manuscript, the authors briefly discuss the mechanism of wax formation in pipelines. Next, a review of various wax-mitigation technologies is provided. The review includes citations of various thermal, chemical, mechanical, biological, and other innovative methods reported by previous researchers and used in the industry.
In this experimental work, the phase boundaries of TMAOH + H2O + CH4 and TMAOH + H2O + CO2 hydrates are measured at different concentrations of aqueous TMAOH solution. The temperature-cycle (T-cycle) method is applied to measure the... more
In this experimental work, the phase boundaries of TMAOH + H2O + CH4 and TMAOH + H2O + CO2 hydrates are measured at different concentrations of aqueous TMAOH solution. The temperature-cycle (T-cycle) method is applied to measure the hydrate equilibrium temperature of TMAOH + H2O + CH4 and TMAOH + H2O + CO2 systems within the ranges of 3.5-8.0 MPa and 1.8-4.2 MPa, respectively. Results reveals that, TMAOH acts as a thermodynamic inhibitor for both gases. In the presence of 10 wt% of TMAOH, the inhibition effect appears to be very substantial for CO2 with an average suppression temperature (∆Ŧ) of 2.24 K. An ample inhibition influence is observed for CH4 hydrate at 10 wt% with ∆Ŧ of 1.52 K. The inhibition effect of TMAOH is observed to increase with increasing TMAOH concentration. Confirmed via COSMO-RS analysis, the TMAOH inhibition effect is due to its hydrogen bonding affinity for water molecules. Furthermore, the calculated hydrate dissociation enthalpies in both systems revealed that TMAOH does not participate in the hydrate crystalline structure.