METHOD FOR MULTILATERAL WELL CONSTRUCTION Russian patent published in 2008 - IPC E21B7/06 

FIELD: oil and gas production industry, particularly to construct oil and gas well clusters.

SUBSTANCE: method involves lowering pipe string in casing pipe in predetermined interval, wherein pipe string has whipstock to be retained with respect to casing pipe so that the whipstock may rotate through predetermined angle; serially cutting windows in casing pipe along casing pipe perimeter by means of cutter secured to flexible shaft end with the use of whipstock to create technological channels in productive reservoir; removing flexible shaft; serially creating technological channels having necessary lengths along casing pipe perimeter with the use of flexible pipe provided with nozzle at one end thereof; supplying high-pressure liquid in the channels to create technological channel group along casing pipe perimeter. After flexible pipe provided with nozzle removal from well the nozzle is substituted for fan-like nozzle. After that flexible pipe having fan-like nozzle is lowered in well up to contact with whipstock. Then each technological channel is reamed with the use of flexible pipe with fan-like nozzle by hot liquid injection through the flexible pipe. The hot liquid has pressure less than that of liquid used for channel forming. After flexible pipe provided with fan-like nozzle removal from well whipstock is detached from casing pipe and fixed over or under initial whipstock location so that whipstock may be rotated through predetermined angle. Then additional technological channel row is created within the same production reservoir in the same way. After pipe string and whipstock removal from well technological pipe string is lowered in casing pipe and packer is installed over technological channels in hole annuity between casing pipe and technological pipe string. After that inner pipe string is lowered in well via technological one and packer is installed between technological channel rows in annuity between casing pipe and inner pipe string.

EFFECT: decreased material consumption and costs due to elimination of additional well constriction in heavy oil reservoirs, prevention of direct heat-carrier contact with casing pipe wall.

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