Prevention of Transition to Overbalanced Conditions in Underbalanced Drilling Operati

Underbalanced drilling (UBD) is a technique that brings various benefits such as reduced formation damage, reduced lost circulation, etc, when drilling a well. However, it is needed to maintain underbalanced condition from the beginning to the end of the drilling operation to guarantee the success of jointed-pipe UBD process. This causes formation damage and potential hazardous drilling problems such as lost circulation and differential sticking to be reduced.
In this paper, various techniques for maintaining continuous underbalanced conditions are given. By employing these techniques, in addition to reduction of drilling problems, well productivity is increased.