METHOD FOR MULTILATERAL WELL CONSTRUCTION Russian patent published in 2011 - IPC E21B7/00 

FIELD: construction.

SUBSTANCE: invention relates to the field of wells drilling, and namely, to method for tunnelling of multibranch oil and gas wells. Underlying borehole is drilled from the main borehole of well cased with casing string and is fixed with tail. Using alignment unit with extracted wedge, a hole is cut in casing string. Specified package is extracted, and a drilled wedge is lowered into well with through hole and perforated pipe, and also with ledge for its engagement with cut hole in casing string. Besides, prior to installation of wedge, below the area of its installation, a sealing device is installed. Fixing agent is injected into interval of drilled wedge using through hole of wedge. Drilling pipes are disconnected from drilled wedge, and remains of fixing agent are washed out. After hardening of fixing agent, an additional borehole is drilled. Then tail is lowered into this borehole on drilling pipes and produced. After WOC, upper part of tail and drilled wedge are drilled to connect the main borehole with underlying borehole, and well development is carried out. Method helps to construct additional boreholes of wells from the main borehole, bottom of casing string in which is not equipped with additional devices.

EFFECT: keeps size of throughput section of the main borehole from top of well to tail with provision of reliability of additional borehole walls fixation.

6 dwg