Device and method for controlling return flow from a bore hole
AssigneeAgr Subsea AS
InventorsMehdi Mir Rajabi, Roger Sverre Stave
Life of this patent
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Abstract
There is provided a device and method for control of return flow from a borehole (18) where drill fluid is supplied from a surface rig (16) via a multi section drill string (4) to a bottom hole assembly (18), the drill pipe sections (6) having tool joints (8) that include an enlarged outer diameter portion (9), and where an annulus (12) is formed between a pipe (2) and the drill string (4), and where the annulus (12) is in fluid communication with or forms part of a return path (40) for the drill fluid, and where a choke (1) is positioned in the annulus (12), and where the length (L) of the choke (1) exceeds the distance (M) between the enlarged outer diameter portion (9) of two adjacent tool joints (8).
Claims21
A device for control of return flow from a borehole where drill fluid is supplied from a surface rig via a multi section drill string to a bottom hole assembly, the device comprising:
- drill pipe sections having tool joints that include an enlarged outer diameter portion,
- an annulus formed between a pipe and the drill string, the annulus being in fluid communication with or forming part of a return path for the drill fluid,
- a choke positioned in the annulus,
- wherein a length of the choke exceeds a distance between the enlarged outer diameter portions of two adjacent tool joints.
A method for control of return flow from a borehole comprising the steps of:
- supplying drill fluid from a surface rig via a device having a multi section drill string to a bottom hole assembly, the device comprising drill pipe sections having tool joints that include an enlarged outer diameter portion;
- an annulus formed between a pipe and the drill string, the annulus being in fluid communication with or forming part of a return path for the drill fluid;
- and a choke positioned in the annulus, and
- extending a length of the choke to exceed a distance between the enlarged outer diameter portions of two adjacent tool joints.
Dependencies are inferred from the claim text.