IVZ media thread, page-5106

"Most other drillers i throw money at seem to run casings as they drill to prevent exactly what we seem to have issues with. Why are we not doing the same? "

We are doing exactly what is normally done. You engineer the well as a series of hole sections and matching casing with progressively smaller diameter. Casing depths are largely controlled by fracture and formation pressure gradients along with the planned mud weight for each hole section.

If a particular zone has a history of mechanical instability or swelling clay issues then that might also be factored into the casing design. In the case of M2 IVZ chose to mitigate the hole deterioration issues by addressing the root causes of same which is sensible and more cost effective approach.