Apparatus and methods for isolating a wellbore junction
AssigneeHalliburton Energy Services, Inc.
InventorsJoseph E. Hess, Benji Smith
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Abstract
A wellbore junction isolation method and associated apparatus provide convenient isolation of a wellbore junction while permitting certain operations to be performed in a main or branch wellbore below the junction. In described embodiments, formations intersected by a main or branch wellbore below a wellbore junction may be stimulated by fracturing after installing an assembly at the wellbore junction, in a straddling and sealing relationship therewith, to isolate it from pressures applied during the fracturing operation. The illustrated isolation assembly may be installed in a single trip into the main wellbore.
Claims26
A method of isolating a junction between a first wellbore and a second wellbore extending outwardly from the first wellbore, the method comprising the steps of:
- providing an elongated assembly including an outer generally tubular structure and an inner generally tubular structure, a first flow passage being formed through the inner structure and a second flow passage being formed between the inner and outer structures;
- sealing a first longitudinal portion of the assembly within a first interior sealing area of the first wellbore uphole of the junction, and sealing a second longitudinal portion of the assembly within a second interior sealing area of a selected one of (1) a portion of the first wellbore downhole from the junction and (2) a portion of the second wellbore, in a manner such that the assembly sealingly straddles the junction with the first and second flow passages being isolated from the non-selected wellbore portion;
- and
- flowing fluid, via one of the first and second flow passages, through the assembly between the sealing areas while returning circulation of the fluid, via the other one of the first and second flow passages through the assembly between the sealing areas.
For use in a subterranean well having a first wellbore extending downwardly from the surface, and a second wellbore extending outwardly from the first wellbore, a method of treating a formation intersected by one of the wellbores, the method comprising the steps of:
- providing an elongated assembly including an outer generally tubular structure and an inner generally tubular structure, a first flow passage being formed through the inner structure and a second flow passage being formed between the inner and outer structures, the assembly further including first and second spaced apart external sealing devices;
- lowering the assembly through the first wellbore in a manner such that the first sealing device is positioned in a portion of the first wellbore uphole of the junction, and the second sealing device is positioned within a selected one of (1) a portion of the first wellbore downhole from the junction, and (2) a portion of the second wellbore;
- sealingly engaging the first and second sealing devices with their associated wellbore portions to thereby cause the assembly to sealingly straddle the junction;
- and
- flowing a well treatment fluid through one of the first and second passages into the selected wellbore portion.
For use in a subterranean well having a first wellbore extending downwardly from the surface and a second wellbore extending outwardly from the first wellbore at a junction therewith, a wellbore isolation system comprising:
- an assembly including an elongated section having first and second sealing devices at opposite ends of the section, the first sealing device sealingly engaging a portion of the first wellbore uphole of the junction, and the second sealing device sealingly engaging a selected one of (1) a portion of the first wellbore downhole from the junction and (2) a portion of the second wellbore, the assembly thereby sealingly straddling the junction, the assembly further including an outer generally tubular structure and an inner generally tubular structure, a first flow passage being formed through the inner structure and a second flow passage being formed between the inner and outer structures;
- and
- fluid flowing through the section via the first flow passage, the first flow passage being isolated from the non-selected wellbore portion.
Dependencies are inferred from the claim text.