SOLUBLE SAFETY COUPLING Russian patent published in 2020 - IPC E21B17/10 

FIELD: soil or rock drilling; mining.

SUBSTANCE: group of inventions relates to drilling operations of a well, namely to a soluble safety coupling used for protection of internal profiles of a downhole tool during drilling operations. Downhole tool comprises a tubular element having a first inner bypass channel and a safety coupling. First inner bypass channel defines the first surface having the first inner diameter and the second recessed surface having the second inner diameter larger than the first inner diameter. Safety coupling is engaged with second recessed surface, wherein safety coupling has second inner bypass channel, which defines third surface, having third inner diameter, which is substantially equal to first inner diameter, so that third surface, in fact, is located flush with first surface. Besides, safety coupling consists of soluble material. Second recessed surface forms a plurality of recesses extending in the longitudinal direction in the tubular member and/or the second recessed surface forms a plurality of recesses extending circumferentially in the tubular member.

EFFECT: technical result is providing accurate installation and extraction of tools for operation in multi-barrel wells.

10 cl, 6 dwg