Definitions for "Casing string"
n: the entire length of all the joints of casing run in a well.
Steel pipe, threaded together and cemented into a well as drilling progresses to prevent the wall of the hole caving in during drilling and to provide a means of extracting oil/gas if the well is productive.
The steel tubing that lines a well after it has been drilled. It is formed from sections of steel tube screwed together.