Prevention of Borehole Diameter Shrinkage in Small Diameter Core Drilling and Treatment

Abstract:

Borehole diameter shrinkage is frequently encountered in small diameter core drilling, which brings serious influence of construction progress, material waste, more construction cost and even downhole accident or abandoned. With several engineering cases, the paper analyzed the causes of borehole diameter shrinkage, introduced process of accident treatment and summed up the experience of penetrating diameter shrinking formation.

Key words:small diameter core drilling; borehole diameter shrinkage; wall protection with mud