Hard ground spud and potential glacial drift, debris, till drilling?
24 April 2010
In the Northern Hemisphere as the ice-age left its mark in the shallow sediments. In general we cannot jet conductors and have to thus drill and safely negotiate through glacial, drift, debris, till that often exists. This can vary from pebble, cobble beds, to sometimes larger bolders. Drilling a quality vertical hole and getting conductors and surface strings in and cemented as trouble free as possible then being the objectives
Wellbore objectives being generally:
- Optimised drilling.
- Wellbore quality (avoid instantaneous (skidded) doglegs, in gauge etc)
- Smooth drilling (avoid shocks, vibration, dynamics effects etc)
In addition to obvious stiffness, rigidity, a semi or well packed, stabilised BHA, shock sub as the obvious candidates to drill a useable hole, and meet requirements from an operational and well engineered standpoint.
What other practices, references, engineered solutions are viewed as best practice, appreciated.