METHOD FOR INSULATION OF BEHIND- -CASING FLOWS IN WELL Russian patent published in 2025 - IPC E21B33/12 

FIELD: obtaining oil and gas from wells.

SUBSTANCE: invention relates to oil and gas industry, namely to methods of insulation of behind-the-casing flows in a well. Method for insulation of behind-the-casing flows in a well includes drilling a deposit with wells crossing a formation consisting of water-saturated and oil-saturated zones, investigation of oil-water-saturated zones of the formation and intervals of their occurrence, lowering and attachment of the casing string with subsequent perforation of the formation in the oil-saturated zone of the formation, cutting out a section of the casing string, expansion of the wellbore in the cut-out section of the casing string, assembly of an assembly consisting of a pipe string with a water-and-oil-swelling packer consisting of an inner pipe and an outer water-and-oil-swelling cuff, installation of water-and-oil-swellable packer opposite to corresponding cut out section of casing string with its subsequent isolation by water-and-oil-swelling cuff. Intervals are determined by geophysical investigations, where behind-the-casing flows occur, in which casing string section is cut out. Inner branch pipe of the water-and-oil swelling packer is made in the middle part in the form of a longitudinally corrugated section, with length of 200-300 mm greater than the corresponding cut-out section of the casing string, and end sections are cylindrical with length sufficient for installation of equipment intended for expansion and pressing of branch pipe to casing string. Water-and-oil-swelling collar 35-55 mm thick is fixed outside the middle part along projections – beams of the branch pipe – at the middle section with length 100-150 mm less than the length of the cut-out section of the casing string, and with thickness 3-10 mm – at ends equal as to length. Casing string section is cut to 1.5-8 m length. In case there are two or more cuts in the casing string, isolation is performed successively from bottom to top. After running in at the string, the water-and-oil-swelling packer is installed in the well so that the middle section of the water-and-oil-swelling collar is located opposite the corresponding cut-out section of the casing string. Installation of the water-and-oil-swellable packer is carried out by expanding the middle part of the branch pipe by excess pressure until pressed to the casing, followed by final pressing of the branch pipe along the entire length to the casing by mandrelling or expansion, then pipe string is removed from well together with equipment for expansion and pressing of branch pipe to casing string and lowering of next water-and-oil-swelling packer or process equipment after installation of last water-and-oil-swelling packer for operation of well after lowering.

EFFECT: proposed method for insulation of behind-the-casing flows in a well allows performing well operation immediately after installation of water-and-oil-swelling packer and removal of process equipment.

4 cl, 6 dwg