Buoyancy assisted running of perforated tubulars
OwnerJohn L. Hood, III, J. David Payneinventors
Life of this patent
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Abstract
The perforations of a pre-perforated tubular are plugged with interior protruding, mostly hollow plugs which temporarily seal the perforations. The plugs are capable of withstanding a significant pressure differential and, when combined with an insert, forming a flotation cavity containing a buoyant fluid. The temporarily sealed tubular is then run into a wellbore, the tubular is set, and the plugs are unsealed. The unsealing is preferably accomplished by drilling out the interior protruding portions. Solid baffles may also be placed in the string to limit buoyant fluid loss in the event of premature unsealing in another embodiment of the invention.
Claims21
An apparatus useful in installing a tubular into a deviated underground wellbore containing a liquid below a surface, said apparatus comprising:
- a tubular portion having a substantially cylindrical wall and a plurality of perforations in a wall of said tubular portion along at least a portion of a lengthwise axis;
- an insert substantially blocking fluid flow in a direction parallel to said axis when said insert is attached within said tubular portion, wherein said insert forms one end nearest said surface of a cavity within said tubular portion and said wall forms part of a side boundary of the cavity;
- and
- a plurality of plugs capable of substantially excluding said liquid from said cavity and containing within said cavity a fluid having a density less than said liquid when said plugs are inserted into said perforations from a substantially radially-inward direction relative to said axis.
An apparatus useful in installing a tubular into a deviated underground wellbore containing a liquid, said apparatus comprising:
- a tubular portion having a substantially cylindrical wall and a plurality of perforations in a tubular wall along at least a portion of a lengthwise axis;
- an insert substantially blocking fluid flow in a direction parallel to said axis when said insert is attached within said tubular portion, wherein said insert forms one end of a cavity within said tubular portion and said wall forms part of a side boundary of the cavity, wherein said insert also forms one end of a second cavity adjacent to the first cavity within the tubular;
- a plurality of plugs capable of substantially excluding said liquid from said cavity when said plugs are inserted into said perforations from a substantially radially-inward direction relative to said axis, wherein said plugs have a substantially hollow core and a solid portion which protrudes inwardly beyond the interior wall of said tubular portion when said plugs are inserted into said perforations and wherein said plugs are capable of withstanding a substantially radially inward directed pressure differential of at least 250 psi;
- equipment capable of running said tubular portion into said deviated wellbore when said cavity contains a gas;
- a float shoe attached to the tubular portion forming a distal end of said cavity;
- means for filling the second cavity with a second liquid;
- and
- means for substantially removing said insert and at least a portion of said plugs when said tubular portion is set within said wellbore.
An apparatus useful in installing a duct into a well containing a first fluid at a first pressure at an underground location below a surface, said apparatus comprising:
- a duct segment having a plurality of perforations, said duct segment forming a portion of a wall of a cavity for containing a second fluid having a density less than said first fluid, said wall substantially excluding said first fluid from said cavity when said duct segment is installed into said well;
- means for removably sealing said perforations when said duct segment is installed within said well;
- means for containing said second fluid within said cavity such that a second fluid pressure within said cavity is substantially less than a first fluid pressure proximate to said cavity when said duct segment is located at said underground location, wherein said means for containing forms an upper end of said cavity and a lower end of a second cavity;
- and
- means for unsealing said perforations when said cavity is located at said underground location and flowing said second fluid towards said surface.
An apparatus useful in installing a duct into a well containing a first fluid at a first pressure at an underground location, said apparatus comprising:
- a duct segment having a plurality of perforations, said duct segment forming a portion of a walls of a cavity for containing a second fluid having a density less than said first fluid, said walls substantially excluding said first fluid from said cavity when said duct segment is installed into said well;
- means for removably sealing said perforations when said duct segment is installed within said well;
- means for filling said cavity with said second fluid such that a second fluid pressure within said cavity is substantially less than a first fluid pressure proximate to said cavity when said duct segment is located at said underground location;
- and
- means for unsealing said perforations when said flotation cavity is located at said underground location;
- means for sealing an upper end of said cavity;
- and
- means for removing said second fluid from said cavity through said tubular.
A process useful in installing a pre-perforated duct segment having a lengthwise axis within a well containing a first fluid, said process comprising:
- inserting plugs into said perforations from a substantially radially inward direction with respect to said axis and forming a plugged duct segment;
- attaching an axial fluid flow restricting device to said duct segment to form one end of a cavity within said plugged duct Segment capable of containing a second fluid having a density less than said first fluid when said plugged duct segment is installed in said well;
- installing said duct segment into said well;
- removing at least a portion of said axial fluid flow restricting device;
- and
- removing at least a portion of said plugs when inserted in said perforations wherein fluid flow through at least a portion of said perforations is enabled.
A process useful in installing a duct segment having perforations along a longitudinal axis within a cavity containing a first fluid, said process comprising:
- attaching radial inflow restriction devices to said perforations;
- attaching an axial flow restriction device to said duct segment, wherein said duct segment and said restriction devices form a flotation portion substantially containing a second fluid which is less dense than said first fluid when said duct segment is translated into a position within said cavity;
- translating said flotation portion into said position within said cavity such that a first fluid pressure proximate to said flotation portion exceeds a second fluid pressure within said flotation portion by at least about 250 psi;
- and
- drilling out at least a portion of said axial flow restriction device and removing said second fluid from said flotation cavity.
An apparatus useful in installing a perforated duct segment into a well containing a first fluid at an underground location below a surface, said apparatus comprising:
- a plurality of plugs for sealing said perforations and forming a portion of a wall of a cavity for containing a second fluid having a density less than said first fluid;
- an insert substantially located within said duct segment and sealing an upper end of said cavity, wherein said insert allows said cavity to be substantially filled with said second fluid when said duct segment is within said well;
- and
- a tool for removing said second fluid from said cavity through said duct segment towards said surface and for unsealing said plugs at said perforations when said cavity is located at said underground location.
An apparatus useful in installing a duct into a well containing a first fluid at an underground location, said apparatus comprising:
- a duct segment having a plurality of perforations;
- a plurality of plugs removably sealing said perforations;
- an insert substantially located within said duct segment and forming one end of a cavity, wherein said insert allows said cavity to contain said second fluid;
- and
- a baffle segmenting said cavity into cavity portions.
Dependencies are inferred from the claim text.