Practice And Application Of Zhongyuan Oil Field’s Underbalanced Drilling Technology In Sichuan Yuanba Project

Underbalanced drilling (UBD) technology began to develop from1950s, which was also called negative pressure drilling technology. And the application of underbalanced drilling has been increasing at home and abroad now. Underbalanced drilling is different from normal drilling:it is very important to control pressure differential for UBD, and down hole and ground circulating system must be well-designed. If pressure differential is too high, it would lead to drilling fault; if it is too low, underbalanced drilling’s performance couldn’t be got. The correlation theory and applied research of under balanced drilling has already become one of highlight study for drilling engineers.Bases on a great deal of demastic and abroad information, this article has a great significance during drilling project, it systematically expounds under balanced drilling technology. First describes the concept of under balanced drilling, type and the development trend, then describes under balanced drilling technology, under balance well completion, under balanced drilling equipment, under balanced drilling engineering design and the under balanced drilling development direction, at last through the under balanced drilling project in Sichuan Yuanba, describes the problem and solution during under balanced drilling. This will help to protect reservoir, improve drilling success rate, reduce drilling cost and prevent accidents during under balanced drilling, is of great significance.