(6fi) Application of Gas Hydrate Slurry Relative Viscosity Models for an Advanced Hydrate Management Strategy

Clathrate hydrates (or gas hydrates) are crystalline structures that trap small gas molecules such as methane, ethane and carbon dioxide in a three-dimensional hydrogen-bonded lattice of water cages. Gas hydrates usually form under high pressure and low temperature conditions. As such, they are considered a nuisance by the oil/gas industry as gas hydrates can plug flowlines. Over several decades, the oil/gas industry has injected Thermodynamic Hydrate Inhibitors (THIs), such as methanol and monoethylene glycol, to completely prevent the formation of gas hydrates in flowlines. However, this method has been proven to be uneconomical especially for maturing fields. In the mid-2000s, there was a paradigm shift in dealing with gas hydrates in flowlines. A new approach called “hydrate management” has been explored, whereby the formation of gas hydrates in flowlines is allowed but its properties are altered by injecting a small amount of Low Dosage Hydrate Inhibitors (LDHIs). The formation of gas hydrates in flowlines changes the flow properties of the fluids, as well as the flow pattern and pressure drop of the system. As a result, advanced knowledge of the rheological properties of gas hydrates slurries is necessary for safe and economic operation of oil/gas flowlines. We have recently developed a model (Majid-Wu-Koh model) for predicting the relative viscosity of a gas hydrate slurry [1]. This new model has been shown to be able to predict the relative viscosity of hydrate slurries for oil-dominated system across various conditions relatively well. The model has also been used for the prediction of pressure drops in large scale flowloop investigations. Limitations of the current relative viscosity model and areas for improvement have been identified. Finally, potential application of the knowledge of rheological properties of hydrate slurries to aid in advancing hydrate management in flowlines will be discussed. Based on the current success of the proposed model, it currently being implemented to industry software. The objective of this work, is to predict the pressure drop of oil/gas flowlines.

References

[1] A. A. A. Majid, D. T. Wu, C. A. Koh, “A Perspective of Rheological Studies of Gas Hydrate Slurry Properties,” Engineering, 2018 (Accepted)

Research Interests: My primary research focused on understanding the transportability of gas hydrate particles in flowlines. In my post-doctoral and doctoral work, I have conducted both lab and large scale research. I conducted several experiments using lab scale high-pressure rheometer to investigate the viscosity change in the presence of gas hydrates. With the knowledge obtained from this investigation, I conducted investigations using a large/industrial scale flowloop in order to confirm my lab results can be translated to large scale facilities. In addition, in my doctoral work, I also conducted research in gas hydrate technology. In this research, I apply my knowledge on gas hydrates properties for engineering application: sea water desalination and natural gas transportation. My future research plan is to focus on understanding the transportability of gas hydrates in flowlines for different conditions: water- and gas-dominated system. This is an interesting area of research since there is no model for predicting the pressure drop for this system. Additionally, I would like to focus my research on thermodynamic and kinetic properties of gas hydrates. It can be said that the thermodynamic properties of gas hydrates are well understood but currently there is limited knowledge on the kinetic properties. This is a crucial knowledge for gas hydrates to be applied for engineering applications.

Teaching Interests:

Beyond my research work, I am also fortunate to obtain various teaching experiences. My first college-level teaching experience was during my senior year where I was an Instructional Aids for Separation Processes (junior level course) as well as a tutor for Chemical Engineering Reaction Kinetics (junior level course). While holding these positions, I was responsible for holding additional lectures for students. These additional lectures focused on students’ critical thinking in problem solving. During my doctoral years, I was also a Teaching Assistant (TA)for Advanced Thermodynamics (graduate level course). From my teaching experience, I learned that it is necessary for the instructor to promote students interest in the subject. As such, as a TA, I always try to relate the materials that I teach in class with my research as well as real world applications. For this reason, my teaching interests are in Thermodynamics and Transport Phenomenon courses as these courses are closely related to my area of research. During my undergraduate years, I found out that these two courses are the most challenging courses. Therefore, I hope that by focusing on these courses, I can help students see the connection between their classroom knowledge with real world applications. I believe by doing this, it promotes interest in students.