Multi-mode pumped riser arrangement and methods
AssigneeEnhanced Drilling AS
InventorsPer Christian Stenshorne, David Edward Smith, Gustav Olov Skärgård
Life of this patent
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Abstract
A riser system in the form of a pumped riser, i.e. a riser having an outlet from the riser at a depth below the surface of a body of water, where the outlet is coupled to a return pump to return fluid from the riser to the surface, and various operational methods to facilitate greater versatility when performing hydrocarbon drilling related operations. A sealing element to seal an annulus of the riser, and a by-pass around the sealing element. Various methods make it possible to switch between open mode and closed mode, and vice versa, monitoring leakage across the sealing element, as well as performing other operations exploiting the advantages of the two different modes.
Claims20
A method of controlling pressure in a riser extending from a bottom of a body of water, the method comprising:
- providing a sealing element at a sealing position in the riser;
- providing a first return outlet from the riser to a return pump below the sealing position;
- providing a second return outlet from the riser between the first outlet and the sealing position;
- pumping drilling fluid downward into a drill string extending along the riser and returning the drilling fluid upward through an annulus formed by the drill string and the riser;
- selectively opening or closing the sealing element, or a sealing element bypass, to manage pressure in the riser;
- operating the return pump to maintain a fluid level in the riser above the first return outlet;
- and
- allowing fluid to flow out of the second return outlet when the fluid level in the riser reaches the level of the second return outlet.
Dependencies are inferred from the claim text.