A lost circulation plug string

Abstract

This utility model discloses a drop-out insertion tubing string for water plugging and locating, relating to the field of water plugging and locating technology in oilfield mechanical extraction. The drop-out insertion tubing string includes a drop-out tube and an insertion tube. The drop-out tube is equipped with a packer, which divides the drop-out tube into at least three sections, simultaneously separating at least three oil-producing layers. The drop-out tube also has fluid inlet channels communicating with each oil-producing layer. The insertion tube has at least a first large-diameter section, a second large-diameter section, and a first small-diameter section. The first small-diameter section is located between the first and second large-diameter sections and has a fluid inlet. The inner cavity of the drop-out tube communicates with the interior of the insertion tube through the fluid inlet. The drop-out tube is equipped with a sealer capable of sealingly engaging with the first and / or second large-diameter sections. By installing a sealer on the drop-out tube, the sealing structure is prevented from contacting and rubbing against the wellbore wall during insertion into the well, improving sealing reliability. Simultaneously, it enables combined production of potential layers, resulting in a high success rate and long effective period.

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