October 2003
Special Focus
Aphron-based drilling fluid: Novel technology for drilling depleted formations
This article describes development and application of the specialized micro-bubbles – based drilling fluid by M-I L.L.C., for controlling downhole mud loss in a depleted reservoir for NAM (Nederlandse Aardolie Maatschappij BV) in the North Sea. Key issues of this project were excessive overbalance drilling conditions (>5,000 psi) leading to the risk of highly expensive lost circulation, and open perforations in the upper producing zone, requiring temporary sealing during drilling. The well was successfully drilled to TD without any drilling losses. Lab methods used to generate appropriate formulations, operational procedures and field application are discussed.
