colonne perdue

OBS: [Une colonne perdue] peut servir de colonne de production si elle relie une couche productive au tubage suivant.

CONT: A liner may serve as the oil string, extending from the producing interval to the next string of casing. A blank liner has no perforations. A perforated liner is perforated or slotted before being placed in the hole. A screen liner is perforated and then arranged with a wire wrapping which acts as a sieve to prevent the entry of sand particles.
OBS: The liner is used to isolate or case off a section of hole below casing that has already been installed. It extends only a short distance into the bottom of the casing string above and does not extend all the way to the surface.