Review of Lost Circulation Mechanisms in a Southern Iraq Oil Field

This paper analyses the lost circulation data (rate, instantaneous downhole pressure and operational conditions) of a Southern Iraq oilfield to develop a mechanism based understanding of the reported mud losses.

Mud losses with varying severity have been reported in all the 27 development wells drilled in the field since 2012. Lost circulation during drilling was identified as the primary cause of Non Productive Time (NPT) for the development wells. Besides cost escalation in terms of lost mud and rig time, uncontrolled mud losses can trigger shale collapse, lead to loss of well control and safety risks.