Comprehensive Analysis of Underbalanced Drilling Jobs in the Middle East

Underbalanced Drilling (UBD) was initially adopted to resolve drilling problems, but it soon became evident that with new technology reservoir damage could be minimized. One common problem that UBD has a positive profound effect is in trouble zones or loss zones. This would include lost circulation; differential pipe sticking and mitigate invasive formation damage which leads to higher hydrocarbon recovery. In this paper, several recent UBD case study wells in Iran have been identified and discussed by comparing certain criteria such as early production, mud loss volumes, actual and planned drilling progress, rate of penetration, practical challenges and technological gaps. Next, an assessment of the success or failure of these UBD wells is carried out. Finally, recommendations are made to resolve the issues for improvement of future works.