Definition - What does Cased Hole mean?
Cased Hole is a pipe with a large diameter that is assembled, inserted and cemented into a section of a recently drilled wellbore. It is replicated with well casing and designed in such a way that it can withstand various forces like burst, collapse and tensile failure, and chemically-excessive brines as well. It is used to protect fresh water formations, and isolate formations or zones of lost returns with different pressure gradients. Running pipe is the operation during which the casing is done.
Petropedia explains Cased Hole
A properly Cased Hole helps the drilling process in several ways like preventing fresh water contamination, unstable upper formations, and isolating various zones with different pressures in drilled formations. The large diameter pipe is inserted during a running pipe operation into an open borehole. It is then cemented in order to stabilize the borehole during the construction process. It forms a major structural component of the borehole and performs several functions. The casing can be found based on the range of sizes and the material grades. The casing design for each size is done by measuring the worst conditions that can be faced during production and drilling.