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

FIELD: oil and gas production industry, particularly to construct multilateral wells in heavy oil pools.

SUBSTANCE: method involves lowering pipe string provided with whip-stock in casing pipe within predetermined interval, wherein the whip-stock is fixed with respect to casing pipe and may serially rotate through specified angle; serially cutting windows in casing pipe along casing pipe perimeter with the use of cutter connected to flexible shaft end by means of whip-stock to provide technological channels in productive pool; removing flexible shaft from well; serially forming technological channels of necessary lengths along casing pipe perimeter, wherein the channels are formed by high-pressure liquid supply through flexible pipe terminating in nozzle; removing flexible pipe from well; substituting nozzle for fan-type nozzle; lowering fan-type nozzle connected to flexible pipe in well up to flexible well cooperation with whip-stock; supplying liquid under pressure less than technological channel creation pressure in well to expand each technological channel with the use of flexible pipe and fan-type nozzle; removing flexible pipe and fan-type nozzle from well; releasing whip-stock from casing pipe; fixing whip-stock over or under initial whip-stock location so that it may be serially rotated through predetermined angle; creating and expanding the second technological channel row within the limits of the same production pool; removing fan-type nozzle with flexible pipe from well; removing pipe string and whip-stock from casing pipe; lowering technological pipe string provided with radial orifices in casing pipe, wherein upper and lower packers are arranged over and under radial orifices; aligning radial orifices with upper row of technological channels, wherein upper packer is installed over the first technological channel row, lower packer is installed between the first and the second technological channel rows in hole annuity between casing pipe and technological pipe string; lowering inner pipe string in well through technological pipe string, wherein lower end of inner pipe string is below technological pipe string end and is aligned with the second technological channel row and lower technological pipe string end is sealed relatively inner pipe string.

EFFECT: decreased costs due to elimination of additional well construction in oil pool and prevention of direct heat-carrier contact with casing pipe wall.

2 dwg