Research Into The Control Technology Of Generating And Decomposing Of Natural Gas Hydrate During The Drilling Process

As a kind of energy,natural gas hydrate has brought great impetus to the development of industry.At the same time,as a critical state substance.Hydrate will bring many well-control problems the process of drilling once it forms,affect the performance of drilling fluid,plugging wellbore、wellhead pipeline、lubricators remit and so on.Researching the formation and mitigation of hydrate in drilling fluids is important for the deepwater drilling operations.The formation of gas hydrate and certain conditions of low temperature and high pressure natural gas components and high-speed airflow flowing pressure fluctuation and tiny hydrate nucleation induction system existence of free water in the situation.In gas supersaturation solution form a stable nucleus with critical dimension,provides a large amount of gas and liquid combination with attachment,lead to increasing crystal nucleus structure of gas-liquid interface,how to realize the formation of hydrate.The temperature and pressure of the wellbore will gradually change during the process of drilling,at appropriate temperature and pressure hydrate will form and decompose constantly.However,the decrease of temperature in the wellbore and the increase of drilling speed will lead to the decomposition of hydrate.In addition,the rate of drilling fluid and chemical additives also have great significance for the formation and decomposition of hydrate.Based on the physical and chemical properties of gas hydrate analysis,The article summed up the various factors which impact the gas hydrate formation and decomposition,analyzed the temperature and pressure distribution in the wellbore and predicted the region in well casing where gas hydrate may generate,Finally,in terms of the mechanisms of the formation and decomposition.,it gives a series of measures which can control the formation and decomposition of gas hydrate in well casing.In order to further study the formation decomposition and control method of gas hydrate,the theoretical foundation is laid.