CIRCULATION VALVE (VERSIONS) Russian patent published in 2012 - IPC E21B34/06 

FIELD: gas and oil production.

SUBSTANCE: circulation valve (CV) includes top and bottom adapters (A), two cases (C) connected to each other and to A. Inside C there are: hollow piston (HP) moving in cup of bottom C under pressure difference effect, two safety bushings (SB), one connected rigidly to HP, springs, gland nut and SB holder. Intratubular space of CV is insulated from annular space by sealing rings (SR). First C features radial hydraulic duct (HD) connecting annular and intratubular space when CV is open. In the first version (CV actuated by intratubular pressure), SB are mounted with a gap against HP, with hydraulic connection of the gap with intratubular space. In the second version (CV actuated by annular space pressure), SB are mounted with a gap against first part of C, with hydraulic connection of the gap with annular space. In initial state, SB are interconnected and CV is closed due to load of springs gauged at certain balance of intratubular and annular space pressure. SB close HD and protect SR against pressure difference effect. When intratubular or annular pressure is applied, one of SB shifts left following HP and opens HD.

EFFECT: increased reliability and functionality.

2 cl, 4 dwg