Patent ID: 11952860
Assignee: CHINA PETROLEUM & CHEMICAL CORPORATION
Field: Civil engineering (Other fields)
Classification: CPC E | IPC E

Claim 12:
13. A staged cementing method with the staged cementing device according to claim 11, comprising steps of:
putting down an opening tool (400) in the staged cementing device to engage with the opening seat (320), and shearing off the second shear pin (182) through the primary pressure build-up, so that the opening seat (320) moves downstream to open the said liquid inlet (130);
causing the swelling liquid to enter the liquid reservoir (240) through the inner chamber (110) of the body (100), the liquid inlet recess (130) and the flow channel (230), thereby causing the packer rubber (220) to expand;
shearing off the first shear pin (180) through the secondary pressure build-up so that the opening sleeve (310) moves downstream to open the circulating opening (120), and at the same time communication between the liquid inlet recess (130) and the flow channel (230) is cut off; and
putting down the closing tool (410) to be in engagement with the closing seat (460), and shearing off the third shear pin (184) through the tertiary pressure build-up, so that the closing sleeve (450) moves downstream to close the circulating opening (120).