Patent ID: 9404347
Filing Date: 2016-08-02
CPC Classification: E21B

Claim Text:
1. A method of connecting a riser from an offshore rig to a subsea structure that includes a first connector, the method comprising: lowering a riser of sufficient length having a second connector at a lower end thereof adapted to connect to the first connector of the subsea structure, wherein the riser is in fluid communication and filled with surrounding water (“first fluid”); closing the riser at a selected location, wherein closing the riser comprises placing a plug inside the riser to prevent fluid communication between the riser and water surrounding the riser; displacing the first fluid in the riser with a second fluid that is heavier than the first fluid to straighten the riser to align the second connector with the first connector, wherein displacing the first fluid with the second fluid comprises: conveying a hollow tubular from the offshore rig into the riser with a bottom end of the tubular extending to a selected location above the plug; and supplying the second fluid into the tubular to move a selected amount of the first fluid out of the riser to straighten the riser; and connecting the second connector to the first connector after conveying the hollow tubular and supplying the second fluid into the tubular to move the selected amount of the first fluid out of the riser.