Gas hydrates pose the major flow assurance problem in the production and transportation of oil and gas. Managing the formation of gas hydrates is central for safe and continuous operation. In this manuscript, we will provide an overview of the Center for Hydrate Research and its efforts toward better understanding the formation, agglomeration, and accumulation of hydrates in multiphase flow. The manuscript will discuss the projects in the Center aimed at quantifying how hydrates can be managed by first understanding the fundamental processes for nucleation, growth, agglomeration, deposition, and plugging, knowledge in these areas that have been accumulated over decades of research. While still a work in progress, significant advances have been made in describing the hydrate formation in oil-dominated, water-dominated, and gas-dominated systems. One of the end goals of our effort is to develop the knowledge and tools to manage hydrates, as opposed to avoidance, in the production and transportation of oil and gas.
Gas hydrates play a significant role in the flow assurance of oil and gas flowlines, posing one of the most serious problems relative to the formation and deposition of other solids (e.g., wax, asphaltenes, scale, etc.). The formation of gas hydrates in flowlines can be not only fast, but also in large volumes, causing unexpected operational problems. Industry has traditionally taken the approach of preventing gas hydrates from forming in flowlines by injection of so-called thermodynamic inhibitor, THI (e.g., methanol, monoethylene glycol), which inhibits hydrate formation in the free water. As seen in Figure 1, in this approach the THI shifts the hydrate equilibrium curve to more severe temperature and pressure conditions, thus allowing the flowline to operate outside the hydrate stability region. While effective in preventing hydrate formation, the costs and quantity of chemical required can be significant.
