MULTILATERAL WELL BUILDING METHOD Russian patent published in 2006 - IPC E21B7/08 

FIELD: well building, particularly to erect multilateral wells.

SUBSTANCE: method involves lowering pipe string provided with diverter at pipe string end in casing pipe; cutting casing pipe within predetermined interval; lowering flexible pipe with nozzle until flexible pipe enters into opened casing pipe zone under the action of the diverter in alternation with supplying pressurized liquid via flexible pipe provided with nozzle; performing translational flexible pipe movement to create additional well bores having necessary lengths along with removing the flexible pipe to create predetermined number of additional bores; finally removing the flexible pipe from the casing pipe. Before casing pipe lowering in the well the casing pipe is provided with rigidly secured hollow insert comprising technological body with through orifices and bush. Inner surface of technological body has guiding means and stop. The bush is inserted in the technological body in air-tight manner so that the bush closes through orifices. The bush is restricted from axial downward displacement by the stop. During casing pipe lowering operation through orifices are located in predetermined opening interval along with following casing pipe securing, the diverter having several guiding channels and axial grooves displaces the bush up to stop and the axial diverter grooves cooperate with guiding means of the hollow insert so that the outlet orifices of the guiding channels are arranged in front of the through orifices. After each additional well bore forming flexible string with nozzle is removed only from diverter to create predetermined number of additional bores.

EFFECT: reduced number of trips.

4 dwg, 1 ex