The operator planned to drill a complex section of a land exploration well through middle and lower Miocene formations, composed of shale interbedded with layers of sand. The aim was to execute a shoe-to-shoe run and set a critical casing inside for the next section. However, eliminating as much rathole as possible was required before the casing for the next section was set.
Drilling 1,376 m in a single run, the operator enlarged the 12.25-in section to 13.5 in in over 57 hours, eliminating 35 m of the rathole under controlled conditions. This performance surpassed the operator’s original expectations of having to drill in two runs over approximately 132 hours, saving 70 hours while avoiding an extra trip.
The Rhino RHE dual-reamer rathole elimination system was equipped with Predator™ cutter block and enhanced indexing and lockout mechanisms to facilitate the use of a dual rathole elimination BHA. This configuration served for both the drillout trip and the simultaneous hole-enlarging-while-drilling (HEWD) operation. When the tools were recovered to surface, no damage was identified in the cutting structure of the tools.
With elimination the Rhino RHE system, a dormant near-bit reamer is activated at TD, and the rathole is enlarged while drilling to avoid adding time to well construction. This eliminates the need for a dedicated rathole cleanout run that can add 24 hours or more to drilling time.
