bouchon de polymères

OBS: On injecte d'abord dans le gisement la solution de polymères; [...] derrière ce «bouchon» qui va pousser devant lui l'huile à déplacer [...] on injecte ensuite de l'eau ordinaire.

CONT: ... it would not be economical to use polymer continuously over the entire life of the flood ... At some time during the early life of the process, injection of polymer solution must be terminated at some ""slug cut-off"" point. This polymer slug is then moved through the reservoir by the continued injection of normal brine.