Description/Application

РК Disconnector is applied for run and cementing of 4", 4.25", 4.488", 5", 5.5" production casings sections 164" - 328" (50 m - 100 m) and more length to eliminate casings leaks.

Spesifications

Design

РК device consists of Body (7), at upper part of which left-hand inner thrust thread is cut, and at lower part-right-hand outer thread corresponding to the thread of ran in well casings. Body (7) is connected to Mandrel (6) with left-hand thread and is sealed to Mandrel with Seal Elements (12). In the middle of Mandrel (6) Sleeve (3) is embedded, which is fixed with Shear Pins (4) and closes circulating ports. Sleeve (3) is sealed to Mandrel (6) with Seal Elements (11). At the lower part of Sleeve (3) is cut outer groove, in which Retaining Ring (5) is set to fix Sleeve and Plug after shearing Shear Pins in Mandrel (6). See the chart.

Operation

Casing section being connected to Disconnector (without Plug) and ran in hole to predetermined depth with tubing or drill pipes.
Circulation is being restored.
Necessary volume of cementing slurry and displacement or drilling mud of necessary weight, equal to inner volume of casing section is pumped in well.
Cementing Plug being launched and after pumping of displacement volume, equal to tubing or drill pipes volume, joins to Sleeve (3) with Plug’s cone tip and wedges itself due to tip 0°30' taper.
With additional 1.45-2.18 KPSI (10 - 15MPa) pressure build up Shear Pins (4), on which Sleeve (3) is fixed, are sheared, and circulating ports of Mandrel (6) get open. At that Sleeve together with Plug moves down to Stop (8), gets latched with Retaining Ring (5) and thus prevents casual back flow at float valve failure.
Excess slurry being flushed out with direct or reverse circulation. Than well is periodically circulated till waiting on cement time finish. Releasing of Mandrel (6) from Body (7) is made with neutral load of Disconnector’s left-hand thread with 20 - 25 right-hand rotations of running tool.