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.

Vol. 224 No. 10

Drilling Report

Aphron-based drilling fluid: Novel technology for drilling depleted formations

A special fluid containing encapsulated micro-bubbles provides mud loss control while drilling through lower-pressure zones

Craig C. White and Adrian P. Chesters, NAM; Catalin D. Ivan, Sven Maikranz and Rob Nouris, M-I L.L.C.

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.

The specialized invasion-control drilling fluid has been developed to drill reservoirs prone to lost circulation. This fluid combines certain surfactants and polymers to create a system of micro-bubbles or aphrons, encapsulated in a uniquely viscosified system.

Aphron-based systems are engineered drilling fluids that aid in well construction by controlling losses in depleted, high-permeability sands while stabilizing pressured shales or other formations. One of the more attractive features of an aphron-based system is that it does not require any of the extra equipment used in air or foam drilling. There are no compressors, high-pressure hoses or connections to add costs and safety concerns. The system uses conventional fluid-mixing equipment to form tough, flexible micro-bubbles.


	This article was adapted from a professional society paper for which World Oil was granted the right to print one time only. Therefore, to review the article, you should refer to the actual World Oil magazine in which it originally appeared.