Study On Underbalanced Drilling Technology In Xujianweizi Gas Field

Under-balance drilling is a new drilling technology developed by1990's, which has adapted the development of exploration and exploitation of Petroleum industry at Present. With many advantages in technology, it grows very soon and has very broad applying prospect. Under-balanced drilling technology is an important research topic in petroleum drilling field. It is strategic to discover and protect hydro carbon reservoir better. Under-balanced drilling is an irreversible and only one-time course, whether it can get the success depends on many controllable and uncontrollable factors. What are the most important technologies are how to optimize the controllable factors, make the under-balanced drilling obtain the expected result safely and successfully, design the proper fluid parameters of under-balanced drilling, and the safe and reliable control system of well-head and surface.As it's advantage, The underbalance drilling technology is researched in view of stratum and reservoir geologic characteristic in weishen 5th well which use a suit of reverse emulsion drilling fluid system in this text, the establish way of underbalance drilling drawdown and density range of drilling fluid are also researched. Additional the well control technique and commensurable auxiliary technique of underbalance drilling are also systematically analysed; a suit of auxiliary technique and well completion scheme of underbalance drilling of negative pressure is established.; and it is successfully used and verified in erbalance drilling construction work,the effect is very ideal.