Master of Science in Petroleum Engineering (MSPE)
Natural gas hydrates are thought to be the future hydrocarbon source of the energy hungry world. Tremendous amount of research has been done to investigate the feasibility of gas production from the hydrate formations. In this direction, three basic production methods, thermal stimulation, depressurization and thermodynamic inhibitor injection have been proposed to produce hydrocarbons off the hydrates. On the other hand, they present high potential risk of drilling hazards, such as severe gasification of drilling fluid, casing collapse due to increase in pressure after dissociation of hydrate zone, and instability of ocean floor, which may cause a platform failure. Scientists and engineers have done very valuable research to understand the phase behavior of hydrates and to prevent hydrate formation throughout the well system during drilling. Reliable hydrate inhibitors have been developed for drilling and production activities. Common practice for the drilling industry has been avoidance of hydrate formations by either abandoning the project or drilling expensive directional wells to reach the target zones for many years. The goal of this project was to quantify the significance of potential problems to allow operational methods and well design to be adopted to minimize the impact of hydrate zone on drilling operations for Eastern Black Sea Offshore Exploration Project. Investigating the existing hydrate dissociation models and adopting a model to predict the amount of dissociated gas was the first step. Further steps were investigation of temperature distribution throughout the well using a thermal simulator and prediction of heat influx from the drilling fluid into the hydrate zone. In this study, hydrate dissociation mechanisms are described. Drilling and production hazards associated with dissociation are stated. For the investigation of hydrate stability/instability, well bore temperature distribution in the near well bore is determined. Hydrate dissociation rate is calculated, and results are evaluated for further changes in drilling program and well design parameters. Results obtained from the dissociation calculations were applied to a set of data from two wells drilled by ARCO/Turkish Petroleum Corporation Joint Venture in Western Black Sea, and were used to design the prospective Eastern Black Sea Offshore Exploration wells.
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Catak, Erdem, "Hydrate dissociation during drilling through in-situ hydrate formations" (2006). LSU Master's Theses. 3965.
John R. Smith