STEP CEMENTING SLEEVE Russian patent published in 2023 - IPC E21B33/14 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the construction of oil and gas wells, in particular to a device - a staged cementing sleeve (SCS), which can be used to prevent the absorption of cement slurry in overlying horizons, represented by high-permeability reservoirs when fastening casing strings. The SCS includes a body with flush ports, tooling, including movable bushings that close and open flush ports, as well as cementing plugs, subs and sealing elements. The rig is made non-drillable and consists of three movable bushings coaxially installed inside the SCS body with the formation of a cavity in the form of a through channel for the passage of cementing plugs, namely a through plug, a bomb and a bomb plug: a bushing that closes the flush windows of the body after cement slurry is pumped during cementing the second stage and obtaining the “stop” moment when dropping a bomb equipped with holes with a diameter equal to the diameter of the flush windows of the body, and a retaining ring that fixes it from axial displacement relative to the body, a bushing that opens the flush windows, and a fixed bushing, fixed relative to the case by a threaded connection and designed for planting a sleeve that opens the flush windows; and an auxiliary bushing designed for planting a bomb plug when closing the flush windows. The fixed bushing is made with hydraulic channels coaxially located on its outer surface, connected to a niche formed when the bushings are installed inside the body during the assembly of the SCS and filled with refractory grease, which excludes the ingress of cement mortar into the SCS cavity and reliable operation of the bushing that closes the flushing windows. The upper part of the fixed bushing and the lower part of the bushing that closes the flushing windows are made with curly mating ends "protrusion - depression" with the possibility of preventing axial rotation relative to the housing. The end surface of the flush windows of the body and the openings of the bushing that closes the flush windows is made with a bevel in the form of knives with the possibility of destroying foreign objects falling into the flush windows and ensuring guaranteed closing of the flush windows.

EFFECT: increased reliability in operation by ensuring the tightness of the casing string, triggering the SCS in case of any complications that arise during cementing and preventing the ingress of cement slurry into the hydraulic cavity of the SCS.

3 cl, 6 dwg