US20170130536A1 - Shoe for a tubular element in a wellbore - Google Patents
Shoe for a tubular element in a wellbore Download PDFInfo
- Publication number
- US20170130536A1 US20170130536A1 US15/320,096 US201515320096A US2017130536A1 US 20170130536 A1 US20170130536 A1 US 20170130536A1 US 201515320096 A US201515320096 A US 201515320096A US 2017130536 A1 US2017130536 A1 US 2017130536A1
- Authority
- US
- United States
- Prior art keywords
- shoe
- fluid
- fluid channel
- plug
- borehole
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
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- 238000005086 pumping Methods 0.000 claims description 13
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- 239000002245 particle Substances 0.000 claims description 5
- 239000011435 rock Substances 0.000 claims description 5
- 239000004568 cement Substances 0.000 description 34
- 238000004873 anchoring Methods 0.000 description 13
- 238000005553 drilling Methods 0.000 description 13
- 125000006850 spacer group Chemical group 0.000 description 13
- 230000004913 activation Effects 0.000 description 8
- 238000003801 milling Methods 0.000 description 8
- 238000007789 sealing Methods 0.000 description 8
- 238000000034 method Methods 0.000 description 5
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- 229910001018 Cast iron Inorganic materials 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 239000004411 aluminium Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
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- 238000013459 approach Methods 0.000 description 1
- 238000005219 brazing Methods 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
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- 238000005552 hardfacing Methods 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
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Images
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
- E21B17/14—Casing shoes for the protection of the bottom of the casing
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B10/00—Drill bits
- E21B10/26—Drill bits with leading portion, i.e. drill bits with a pilot cutter; Drill bits for enlarging the borehole, e.g. reamers
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B10/00—Drill bits
- E21B10/60—Drill bits characterised by conduits or nozzles for drilling fluids
- E21B10/602—Drill bits characterised by conduits or nozzles for drilling fluids the bit being a rotary drag type bit with blades
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B33/00—Sealing or packing boreholes or wells
- E21B33/10—Sealing or packing boreholes or wells in the borehole
- E21B33/12—Packers; Plugs
- E21B33/1204—Packers; Plugs permanent; drillable
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B34/00—Valve arrangements for boreholes or wells
- E21B34/06—Valve arrangements for boreholes or wells in wells
- E21B34/063—Valve or closure with destructible element, e.g. frangible disc
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B29/00—Cutting or destroying pipes, packers, plugs or wire lines, located in boreholes or wells, e.g. cutting of damaged pipes, of windows; Deforming of pipes in boreholes or wells; Reconditioning of well casings while in the ground
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/02—Subsoil filtering
- E21B43/10—Setting of casings, screens, liners or the like in wells
- E21B43/103—Setting of casings, screens, liners or the like in wells of expandable casings, screens, liners, or the like
Definitions
- the present invention relates to a shoe for a tubular element in a borehole extending into an earth formation.
- Wellbores for the production of hydrocarbon fluid generally are provided with steel casings and/or liners to provide stability to the wellbore wall and to prevent undesired flow of fluid between the wellbore and the surrounding earth formation.
- a casing generally extends from surface into the wellbore, whereas a liner may extend only a lower portion of the wellbore.
- casing and liner are used interchangeably and without such intended difference.
- the wellbore is drilled in sections whereby each section is drilled using a drill string that has to be lowered into the wellbore through a previously installed casing.
- the wellbore and the subsequent casing sections decrease in diameter with depth.
- the production zone of the wellbore therefore has a relatively small diameter in comparison to the upper portion of the wellbore.
- Subsequent wellbore sections may therefore be drilled at a diameter larger than in the conventional wellbore. If each casing section is expanded to the same diameter as the previous section, the wellbore diameter may remain substantially constant with depth.
- the shoe at the lower end of the casing may encounter obstructions such as ledges, rock particles and debris.
- obstructions such as ledges, rock particles and debris.
- U.S. Pat. No 6,401,820 B1 discloses a liner shoe provided with jetting ports provided at an eccentric nose portion of the shoe.
- Such jetting ports may become clogged, for example during pumping of cement into the wellbore, thereby potentially leading to damage to the shoe and/or to unsuccessful cementation of the casing in the wellbore.
- US patent application US2010/0252331 discloses a reamer shoe that is able to drill through modest obstructions within a previously drilled borehole and which is provided with nozzles (25) formed by apertures and frangible regions that can be breached to form additional apertures (28) that may be used to provide fluid communication between the interior and exterior of the reamer shoe when the nozzles (25) are plugged.
- a disadvantage of this known reamer shoe is that the frangible regions do not have larger flow areas than the nozzles, so that when the nozzles (25) are clogged by large size debris, also the additional apertures (28) will be clogged by such large size debris.
- a shoe for a tubular element in a borehole extending into an earth formation comprising a body adapted to be connected to the lower end of the tubular element, the body being provided with:
- the fluid pressure in the fluid channel increases as pumping proceeds until the pressure reaches the selected overpressure at which the closure device opens and debris that plugged the nozzles is cleared via the additional fluid outlet.
- the fluid outlet becomes available for discharging fluid from the fluid channel into the borehole.
- the closure device forms a safety system that prevents damage to the shoe due to the pressure rating of the shoe being exceeded.
- the cementation procedure may proceed by pumping cement via the fluid outlet into the borehole once the closure device has opened.
- the closure device includes a section of reduced wall thickness of the body, which section is arranged to shear off from the body upon the fluid pressure in the fluid channel reaching the selected overpressure.
- the section of reduced wall thickness may comprise a burst plate.
- the fluid outlet may have a flow area of, for example, between about 2 to 3 square inch (12 to 20 cm 2 ).
- the total flow area of said at least one nozzle may be less than 1 square inch (6.5 cm 2 ).
- the fluid channel may be provided with a seat for receiving a plug for closing the fluid channel.
- the fluid channel may be provided with locking means for locking the plug in the fluid channel.
- the locking means may comprise a recess formed in a selected one of the fluid channel and the plug, and the other of the fluid channel and the plug may be provided with a locking member arranged to snap into the recess upon the plug landing on the seat.
- the recess comprises an annular groove formed in the fluid channel, and the locking member comprises a lock ring provided to the plug.
- the body may be provided with a chamber arranged to receive debris from the fluid channel, wherein the plug is adapted to move the debris from the fluid channel into the chamber.
- the body includes a flange provided with at least one radially extending rib, each rib being arranged to prevent rotation of the flange during drilling-out of the shoe in the borehole.
- the body may include a reamer for reaming the borehole during lowering of the tubular element into the borehole.
- Each nozzle may be positioned at the reamer.
- the reamer has a nose section arranged eccentrically relative to a central longitudinal axis of the tubular element when the shoe is connected to the tubular element.
- the reamer may be provided with at least one cutter blade for cutting rock particles during reaming of the borehole, each cutter blade being arranged to prevent rotation of the reamer during drilling-out the shoe in the borehole.
- the tubular element may be, for example, a casing or a liner adapted to be arranged in the borehole.
- the shoe may be included in a bottom plug arranged in an expandable casing or liner below an expander for expanding the casing or liner in the borehole.
- FIG. 1 schematically shows an assembly including a first embodiment of the shoe of the invention
- FIG. 2 schematically shows the assembly after pumping cement into the wellbore
- FIG. 3 schematically shows the assembly during expansion of the clad element
- FIG. 4 schematically shows the assembly after the bottom plug has been set
- FIG. 5 schematically shows the assembly during drilling-out of the bottom plug
- FIG. 6 schematically shows a modified bottom plug for use in the assembly
- FIGS. 7 a - d schematically show an assembly including a second embodiment of the shoe of the invention.
- FIG. 1 shows an assembly 1 for expanding a tubular element 2 in a wellbore 3 extending into an earth formation 4 .
- the assembly 1 comprises a primary expander 6 connected to an expansion mandrel 8 suspended in the wellbore 3 on a drill string (not shown) that normally may be used for drilling of the wellbore.
- the primary expander 6 has a cylindrical upper portion 6 a of diameter substantially equal to the inner diameter of the unexpanded tubular element 2 and a conical lower portion 6 b of diametrical size adapted to expand the tubular element 2 to the desired diameter to form a liner in the wellbore 3 .
- the tubular element 2 is suspended on the primary expander 6 whereby the cylindrical portion 6 a thereof extends into the lower end of the tubular element 2 .
- the assembly 1 furthermore comprises a bottom plug 10 arranged below the primary expander 6 and connected to a plug mandrel 12 in releasable manner, the plug mandrel being fixedly connected to the lower end of the expansion mandrel 8 .
- the plug mandrel 12 , the expansion mandrel 8 and the drill string have a common fluid channel 13 for fluid pumped from surface to the bottom plug 10 .
- the bottom plug 10 comprises a flange 14 having a recess 16 into which a lower end part 18 of the plug mandrel 12 fits.
- the recess 16 and lower end part 18 have complementary hexagonal shapes so as to allow torque to be transmitted between the plug mandrel 12 and the bottom plug 10 , however any other suitable shape may be selected to allow torque to be transmitted.
- a radially expandable tubular clad element 20 is fixedly connected to the flange 14 and extends coaxially around the plug mandrel 12 .
- a secondary expander 22 is arranged inside the clad element 20 , the secondary expander having a cylindrical upper portion 22 a of diameter substantially equal to the inner diameter of the unexpanded clad element 20 and a conical lower portion 22 b of maximum diameter adapted to expand the clad element 20 against the inner surface of tubular element 2 after radial expansion thereof.
- the clad element 20 has a launcher section in the form of thin walled lower section 24 with an oversized inner diameter to accommodate the conical lower portion 22 b of the secondary expander.
- the clad element further includes a lower anchoring section 26 , an upper anchoring section 28 axially spaced from the lower anchoring section, and a sealing section 30 located between the lower and upper anchoring sections 26 , 28 .
- Each anchoring section 26 , 28 is at the outer surface provided with a coating of friction material, for example a coating including carbide particles embedded in a substrate that is metallically bonded to the outer surface by means of laser welding.
- the sealing section 30 is at the outer surface provided with annular seals 34 .
- the plug mandrel 12 extends through a central bore 36 of the secondary expander 22 in a manner allowing the secondary expander 22 to slide in axial direction along the plug mandrel 12 .
- the plug mandrel 12 is provided with flow ports 38 fluidly connecting the fluid channel 13 with a fluid chamber 40 formed between the large diameter end of the secondary expander 22 and the flange 14 . Initially the axial size of the fluid chamber 40 is very small but increases during expansion of the clad element 20 as will be explained hereinafter.
- the upper end of the clad element 20 is covered by a removable debris cap 42 having a central bore 44 through which the plug mandrel 12 extends in a manner allowing the debris cap 42 to slide in axial direction along the plug mandrel 12 .
- the debris cap 42 serves to prevent debris entering the clad element 20 prior to radial expansion thereof.
- the bottom plug 10 is provided with a reamer 45 having outlet openings in the form of nozzles 46 in fluid communication with the fluid channel 13 via an internal chamber 47 of the reamer and a bore 48 in the flange 14 .
- the chamber 47 has a wall section of reduced thickness in the form of burst plate 49 that is adapted to shear off at a selected fluid overpressure in the chamber 47 relative to a fluid pressure in the borehole i.e. exterior of the bottom plug 10 . When sheared off, the burst plate 47 leaves a fluid outlet from the chamber with a flow area larger than the flow area of each nozzle 46 .
- the bore 48 has a seat 50 for receiving a trailing plug 52 ( FIG. 2 ) to close the bore.
- FIG. 2 shows the assembly 1 whereby a fluidic cement column 53 surrounds the tubular element 2 and the assembly 1 .
- the trailing plug 52 is received on the seat of the bore 48 and thereby closes the bore.
- FIG. 3 shows the assembly 1 after a lower portion 54 of the tubular element 2 has been expanded by the primary expander 6 , whereby the bottom plug 10 is positioned in the expanded lower portion 54 and the clad element 20 is partly expanded against the inner surface of the expanded lower portion 54 .
- a volume of hydraulic fluid 56 such as spacer fluid or drilling fluid, has been pumped into the fluid chamber 40 via the fluid channel 13 and flow ports 38 .
- FIG. 4 shows the assembly 1 after the clad element 20 has been fully expanded against the inner surface of the expanded lower portion 54 of the tubular element 2 , whereby the plug mandrel 12 is released from the flange 14 .
- the secondary expander 22 and the debris cap 42 maintain positioned at the plug mandrel.
- FIG. 5 shows the assembly 1 after tubular element 2 has been fully expanded, and the expansion mandrel 8 and the plug mandrel 12 together with the secondary expander 22 and the debris cap 42 have been removed from the wellbore 3 .
- a drill string 58 with a polycrystalline diamond compact (PDC) bit 60 is lowered into the expanded tubular element 2 to drill out the remainder of the bottom plug 10 .
- PDC polycrystalline diamond compact
- a dedicated milling tool may be applied to drill out the remainder of the bottom plug.
- FIG. 6 shows a modified bottom plug 64 which is substantially similar to the bottom plug 10 except regarding the following.
- the reamer 45 has a nose section 66 arranged eccentrically relative to a central longitudinal axis of the plug mandrel 12 .
- the modified bottom plug 64 is provided with an activation sleeve 68 positioned in the bore 48 to temporarily close the flow ports 38 .
- the activation sleeve 68 is locked in place by suitable shear pins (not shown) and is adapted to slide axially downward through the bore 48 when the shear pins are broken whereby the flow ports 38 are freed.
- the seat 50 for the trailing plug 52 is provided in the activation sleeve 68 rather than in the bore 48 .
- the modified bottom plug 64 is provided with a protective sleeve 70 extending around the sealing section 30 and the anchoring sections 26 , 28 of the clad element 20 .
- the sleeve 70 is fixedly connected to the debris cap 42 , the latter having a cylindrical part 42 a that extends into the clad element 20 and abuts against the secondary expander 22 .
- Reamer 45 , flange 14 and clad element 20 are interconnected by a crossover sub 71 .
- FIGS. 7 a to 7 d show an assembly 80 using a second embodiment of the shoe of the invention, whereby FIG. 7 a shows a side view and FIGS. 7 b - d show a longitudinal section of the assembly.
- the assembly 80 includes a shoe 82 connected to the lower end of a wellbore casing (or liner) 84 .
- the shoe 82 is provided with a reamer 86 having an eccentric nose section 87 relative to a central longitudinal axis of the casing 84 .
- the reamer 86 is provided with nozzles in the form of flow ports 88 to enable drilling fluid to be circulated during running into a wellbore.
- the size of the flow ports 88 is such that the total flow area of the flow ports 88 is similar to, for example, the flow area of a conventional PDC drill bit i.e. typically less than 1 square inch so as to provide the necessary jetting action for hole cleaning purposes.
- the flow ports 88 are arranged such that an optimum flow distribution and scavenging of the wellbore by jet action is obtained.
- the inner surfaces of the flow ports may be provided with a hard facing to mitigate erosion during circulation.
- the reamer 86 is at its outer surface provided with a plurality of cutter blades 90 having abrasion resistant cutting elements 92 e.g. carbides that may be brazed on the outer surface of the reamer.
- the reamer 86 is connected to the casing 84 by means of a crossover sub 94 which forms the transition between the casing 84 and a flange 96 of the shoe 82 .
- the flange 96 is provided with a profiled bore 98 having a seat 99 for receiving a trailing plug 102 ( FIG. 7 d ) used during pumping cement into the wellbore.
- the bore 98 is in fluid communication with the flow ports 88 via a chamber 103 formed in the shoe.
- a groove 104 is provided in the bore 98 to enable the trailing plug 102 to be locked in place once seated ( FIG. 7 d ).
- the flange 96 may optionally be provided with radial ribs (not shown) that are surrounded by cement after cementation to prevent rotation of the flange 96 during drilling out the shoe from the wellbore. Further, the flange 96 may optionally be provided with arms (not shown) connected to the reamer 86 to provide mechanical support to the reamer.
- the reamer 86 has a section of reduced wall thickness in the form of burst plate 108 that is adapted to shear off from the reamer at a selected fluid overpressure in the chamber 103 relative to a fluid pressure in the borehole i.e. exterior of the shoe 82 . When sheared off, the burst plate 108 leaves an outlet opening 109 of chamber 103 with a flow area larger than the flow area of each flow port 88 ( FIG. 7 c ).
- the assembly 1 is lowered into the wellbore 3 on drill string and may be rotated to ream sections of the wellbore 3 by reamer 45 . Simultaneously drilling fluid may be pumped into the wellbore via fluid channel 13 , chamber 47 and nozzles 46 . The pumped fluid assists in reaming the wellbore and transports rock particles to surface.
- the tubular element 2 is at its upper end anchored in the wellbore 3 .
- leading spacer fluid (not shown) is pumped into the wellbore via the fluid channel 13 to clean the fluid channel from drilling fluid, followed by the fluidic cement column 53 and the trailing spacer fluid 56 ( FIG. 3 ).
- drilling fluid may be used instead of trailing spacer fluid.
- the leading spacer fluid and the fluidic cement 53 may be separated by a foam ball that crushes upon arriving in the bore 48 of the bottom plug 10 and is released through the outlet openings 46 .
- the fluidic cement and the trailing spacer fluid 56 are separated by the trailing plug 52 that seats on the seat 50 upon arriving in the bore 48 .
- the trailing spacer fluid 56 is present in the fluid channel 13 , and the cement column surrounds the bottom plug 10 and the tubular element 2 .
- the trailing plug 52 closes the bore 48 and thereby seals the fluid channel 13 from the annular space around the assembly 1 in the wellbore 3 .
- the primary expander 6 abuts against the lower end of the tubular element 2 therefore fluidic cement cannot enter the tubular element 2 ( FIG. 2 ).
- the fluid pressure in chamber 47 increases as pumping continues until the burst plate 49 shears off upon the fluid pressure reaching the selected overpressure.
- the relatively large flow area in the wall section of the former burst plate becomes available for pumping cement into the wellbore.
- the burst plate 49 forms a contingency device that prevents a catastrophic situation whereby the cementing procedure cannot be completed successfully.
- the burst plate 49 also protects the reamer 45 against pressure shockwaves that may occur in the fluid channel 13 , for example during setting of a liner hanger or the activation of the expansion system. Such shockwaves may have amplitudes up to 3500 psi and will almost entirely reflect against the reamer 45 thereby doubling in amplitude. The burst plate 49 shears off at such high pressure peaks and thereby protects the reamer 45 against damage or failure.
- the primary expander 6 is pulled into the tubular element 2 by pulling the drill string whereby the lower portion 54 of the tubular element 2 is expanded ( FIG. 3 ). Expansion is proceeded until the bottom 10 plug is fully inside the expanded lower portion 54 . While maintaining the drill string under tension, fluid pressure is applied in the fluid channel 13 so that the trailing spacer fluid 56 flows via the flow ports 38 of the plug mandrel 12 into the fluid chamber 40 . The secondary expander 22 thereby slides along the plug mandrel 12 away from the flange 14 and gradually expands the clad element 20 against the expanded lower portion 54 of the tubular element 2 .
- the lower anchoring section 26 first engages the expanded lower portion 54 , followed by the sealing section 30 and subsequently the upper anchoring section 28 .
- the sealing section 30 engaging the expanded lower portion 54
- the tubular element 2 is simultaneously further expanded with the primary expander 6 to maintain volume balance in the expanded section of the tubular element 2 between the bottom plug 10 and the primary expander 6 .
- the secondary expander 22 moves out of the clad element and thereby pushes the debris cap 42 off the clad element 20 .
- the interior of the expanded clad element 20 is then filled with trailing spacer fluid that may be contaminated with cement.
- the remainder of the tubular element 2 is expanded with the primary expander 6 whereby the secondary expander 22 and the debris cap 42 are carried out of the wellbore 3 on the plug mandrel 12 ( FIG. 4 ).
- fluid pressure can be applied below the primary expander 6 via the fluid channel 13 to provide additional upward force to the primary expander 6 (hydraulic assist).
- the entire expansion force required to expand the tubular element 2 may be provided by such fluid pressure i.e. without applying tensile force to the drill string.
- the design functionalities of the upper and lower anchoring sections 26 , 28 and the sealing section 30 are as follows.
- the clad element is subjected to balloon deformation whereby the lower anchoring section 26 becomes firmly pressed against the expanded tubular element 2 .
- the fluid pressure below the bottom plug 10 is higher than the fluid pressure in the interior space of the fully expanded clad element 20 , for example due to swab pressure below the primary expander 6 during expansion of the tubular element 2
- the clad element is subjected to balloon deformation whereby the upper anchoring section 28 becomes firmly pressed against the expanded tubular element 2 .
- the bottom plug 10 is drilled out with the PDC bit 60 or milling tool on drill string 58 whereby the bottom plug is supported by the cement 53 surrounding it ( FIG. 5 ).
- the cement 53 is pumped into the wellbore after the lower portion 54 of the tubular element has been expanded and the bottom plug 10 has been pulled into the expanded lower portion 54 .
- This approach may be followed if there is a risk that the secondary expander 22 is activated before the bottom plug 1 is inside the lower portion 54 of the tubular element, e.g. due to pressure waves in the fluid channel 13 propagating into the fluid chamber 40 during pumping of cement into the wellbore.
- there is reduced annular space between the expanded lower portion 54 of the tubular element and the wellbore wall the pressure drop required to pump the cement at a certain rate through the annular space increases, which may lead to an increased risk of formation fracturing in critical pressure regimes.
- Stabilization of the PDC bit or milling tool 60 during drilling-out of the bottom plug 10 may be optimized as follows.
- the clad element 20 is hydraulically expanded with the trailing spacer fluid 56 as a pressure medium. Consequently after completion of the expansion process the interior of the clad element 20 is filled with trailing spacer fluid that may be contaminated with some cement.
- an additional volume of cement may be pumped behind the trailing plug 52 to expand the clad element 20 .
- a trailing foam ball (not shown) may be pumped behind the cement, optionally followed by trailing spacer fluid.
- the installation process is continued as described above whereby the pressure medium used for the expansion of the clad element 20 is cement rather than trailing spacer fluid or drilling fluid.
- the trailing foam ball is pumped out of the plug mandrel 12 into the wellbore.
- the bottom plug 10 is surrounded by cured cement, optionally with excess cured cement above the clad element 20 to mitigate the risk of damage to the PDC bit or milling tool 60 upon tagging the bottom plug 10 and to provide optimum conditions for drilling-out of the bottom plug 10 .
- the risk of damage to the cutters of the PDC bit or milling tool 60 when tagging the top of the clad element 20 can be further mitigated by connecting a short pipe section (not shown) of a soft metal, for example copper, to the top of the clad element 20 .
- the pipe section is subjected to plastic deformation due to loading by the PDC cutters thereby limiting the peak contact load and thus the risk of impact damage to the PDC cutters.
- Normal operation of the assembly 1 when provided with the modified bottom plug is substantially similar to normal operation described above.
- the eccentric nose section 66 of the reamer 45 helps in preventing rotation of the reamer during drilling out the bottom plug 10 with the PDC bit 60 or the milling tool.
- the activation sleeve 68 prevents unintentional expansion of the clad element 20 by the secondary expander 22 due to fluid pressure peaks in the fluid channel 13 before the trailing plug 52 has landed in the activation sleeve. As the trailing plug 52 lands into the activation sleeve 68 , the trailing plug pushes the activation sleeve downward whereby the shear pins 69 are broken and the flow ports 38 are freed.
- the protective sleeve 70 protects the sealing section 30 and the anchoring sections 26 , 28 before expansion of the clad element 20 .
- the protective sleeve 70 moves in axial direction away from the clad element 20 together with the debris cap 42 . In this manner optimum protection is provided to the sealing section 30 and the anchoring sections 26 , 28 which become exposed only just before the secondary expander expands these sections.
- the cutter blades 90 cut the cavings into jettable chunks which are transported to surface by the circulating drilling fluid.
- a volume of cement is pumped into the wellbore via the bore 98 , the chamber 103 and the flow ports 88 .
- the cement fills up the annulus between the casing and the wellbore wall.
- the trailing plug 102 is pumped onto the seat 99 of the flange 96 ( FIG. 7 d ).
- An elastomer seal (not shown) at the outer surface of the trailing plug seals the trailing plug relative to the bore 98 .
- a lock ring 110 of the trailing plug snaps into the groove 104 so as to prevent the trailing plug from being pushed back by U-tubing pressure of the cement. Any debris that may be present in the bore 98 is pushed into the chamber 103 by the trailing plug 102 as the latter lands into the bore 98 .
- the relatively small size of the flow ports 88 involves the risk of clogging of the flow ports 88 during cementation.
- the fluid pressure in the reamer 86 will increase until the pressure rating of the burst plate 108 is exceeded so that the burst plate shears off.
- a new flow port 112 with a flow area of some 2-3 square inches is provided which is typical for conventional cementing shoes. This enables the cementing operation to be completed successfully by pumping the remainder of the cement via the new flow port 112 into the annulus.
- the shoe 82 is drilled out preferable using a PDC drill bit.
- the components of the shoe 82 are bonded to the cured cement and therefore are locked in place during drilling out.
- the ribs (if present) and the cutter blades 90 assist in such locking of the components.
- the eccentric nose section 87 of the reamer 86 prevents rotation of the reamer with the drill bit.
- All components to be drilled out are suitably made from easily drillable material e.g. cast iron or aluminium, and the cutting elements on the cutting blades are of small size and are embedded in a relatively soft substrate such as brazing material. In this manner the hard cutting elements can easily be broken out of the substrate and discharged from the wellbore by the drilling fluid.
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Abstract
A well casing or liner shoe (10) comprises a partially of fully openable central fluid channel (13) which is connected to at least one small width nozzle (46) and an additional large width fluid outlet (49), which is closed by a thin walled closure device arranged to open at a selected fluid overpressure in the fluid channel (13), and which has a flow area larger than each nozzle (46) to permit fluid circulation when the nozzles (46) are clogged and clearance of clogging debris through the additional large width additional fluid outlet (49).
Description
- The present invention relates to a shoe for a tubular element in a borehole extending into an earth formation.
- Wellbores for the production of hydrocarbon fluid generally are provided with steel casings and/or liners to provide stability to the wellbore wall and to prevent undesired flow of fluid between the wellbore and the surrounding earth formation. A casing generally extends from surface into the wellbore, whereas a liner may extend only a lower portion of the wellbore. However in the present description the terms “casing” and “liner” are used interchangeably and without such intended difference.
- In a conventional wellbore, the wellbore is drilled in sections whereby each section is drilled using a drill string that has to be lowered into the wellbore through a previously installed casing. In view thereof the wellbore and the subsequent casing sections decrease in diameter with depth. The production zone of the wellbore therefore has a relatively small diameter in comparison to the upper portion of the wellbore. In view thereof it has been proposed to drill a “mono diameter” wellbore whereby the casing or liner to be installed is radially expanded in the wellbore after lowering to the required depth. Subsequent wellbore sections may therefore be drilled at a diameter larger than in the conventional wellbore. If each casing section is expanded to the same diameter as the previous section, the wellbore diameter may remain substantially constant with depth.
- During installation of the casing into the wellbore, either conventional or mono diameter, the shoe at the lower end of the casing may encounter obstructions such as ledges, rock particles and debris. To overcome such obstructions it has already been proposed to provide the casing shoe with reaming members and ports for pumping fluid into the wellbore.
- U.S. Pat. No 6,401,820 B1 discloses a liner shoe provided with jetting ports provided at an eccentric nose portion of the shoe.
- Such jetting ports may become clogged, for example during pumping of cement into the wellbore, thereby potentially leading to damage to the shoe and/or to unsuccessful cementation of the casing in the wellbore.
- US patent application US2010/0252331 discloses a reamer shoe that is able to drill through modest obstructions within a previously drilled borehole and which is provided with nozzles (25) formed by apertures and frangible regions that can be breached to form additional apertures (28) that may be used to provide fluid communication between the interior and exterior of the reamer shoe when the nozzles (25) are plugged. A disadvantage of this known reamer shoe is that the frangible regions do not have larger flow areas than the nozzles, so that when the nozzles (25) are clogged by large size debris, also the additional apertures (28) will be clogged by such large size debris.
- There is a need for an improved shoe for a tubular element in a borehole extending into an earth formation, which overcomes the drawbacks of the prior art.
- In accordance with the invention there is provided a shoe for a tubular element in a borehole extending into an earth formation, the shoe comprising a body adapted to be connected to the lower end of the tubular element, the body being provided with:
-
- a fluid channel;
- at least one nozzle for jetting fluid into the borehole, each nozzle being in fluid communication with the fluid channel; and
- an additional fluid outlet for pumping fluid from the fluid channel into the borehole, the fluid outlet being closed by a closure device arranged to open at a selected fluid overpressure in the fluid channel relative to a fluid pressure in the borehole;
- characterized in that the additional fluid outlet has a flow area larger than each nozzle.
- In this manner it is achieved that, in case one or more of the nozzles become clogged, the fluid pressure in the fluid channel increases as pumping proceeds until the pressure reaches the selected overpressure at which the closure device opens and debris that plugged the nozzles is cleared via the additional fluid outlet. Thereby the fluid outlet becomes available for discharging fluid from the fluid channel into the borehole. Thus the closure device forms a safety system that prevents damage to the shoe due to the pressure rating of the shoe being exceeded. Moreover, if such clogging occurs during pumping cement into the wellbore, the cementation procedure may proceed by pumping cement via the fluid outlet into the borehole once the closure device has opened.
- Suitably the closure device includes a section of reduced wall thickness of the body, which section is arranged to shear off from the body upon the fluid pressure in the fluid channel reaching the selected overpressure. For example, the section of reduced wall thickness may comprise a burst plate.
- The fluid outlet may have a flow area of, for example, between about 2 to 3 square inch (12 to 20 cm2). The total flow area of said at least one nozzle may be less than 1 square inch (6.5 cm2).
- Advantageously the fluid channel may be provided with a seat for receiving a plug for closing the fluid channel. Further, the fluid channel may be provided with locking means for locking the plug in the fluid channel. For example, the locking means may comprise a recess formed in a selected one of the fluid channel and the plug, and the other of the fluid channel and the plug may be provided with a locking member arranged to snap into the recess upon the plug landing on the seat. In one embodiment the recess comprises an annular groove formed in the fluid channel, and the locking member comprises a lock ring provided to the plug.
- To promote proper seating of the plug into the fluid channel, the body may be provided with a chamber arranged to receive debris from the fluid channel, wherein the plug is adapted to move the debris from the fluid channel into the chamber.
- Suitably the body includes a flange provided with at least one radially extending rib, each rib being arranged to prevent rotation of the flange during drilling-out of the shoe in the borehole.
- Also, the body may include a reamer for reaming the borehole during lowering of the tubular element into the borehole. Each nozzle may be positioned at the reamer.
- To prevent rotation of the reamer with the drill bit or milling tool during drilling-out the shoe, suitably the reamer has a nose section arranged eccentrically relative to a central longitudinal axis of the tubular element when the shoe is connected to the tubular element. Furthermore, the reamer may be provided with at least one cutter blade for cutting rock particles during reaming of the borehole, each cutter blade being arranged to prevent rotation of the reamer during drilling-out the shoe in the borehole.
- The tubular element may be, for example, a casing or a liner adapted to be arranged in the borehole. Alternatively the shoe may be included in a bottom plug arranged in an expandable casing or liner below an expander for expanding the casing or liner in the borehole.
- The invention will be described hereinafter in more detail and by way of example, with reference to the accompanying schematic drawings in which:
-
FIG. 1 schematically shows an assembly including a first embodiment of the shoe of the invention; -
FIG. 2 schematically shows the assembly after pumping cement into the wellbore; -
FIG. 3 schematically shows the assembly during expansion of the clad element; -
FIG. 4 schematically shows the assembly after the bottom plug has been set; -
FIG. 5 schematically shows the assembly during drilling-out of the bottom plug; -
FIG. 6 schematically shows a modified bottom plug for use in the assembly; and -
FIGS. 7a-d schematically show an assembly including a second embodiment of the shoe of the invention. - In the description and the figures, like reference numerals relate to like components.
-
FIG. 1 shows anassembly 1 for expanding atubular element 2 in awellbore 3 extending into anearth formation 4. Theassembly 1 comprises aprimary expander 6 connected to anexpansion mandrel 8 suspended in thewellbore 3 on a drill string (not shown) that normally may be used for drilling of the wellbore. Theprimary expander 6 has a cylindricalupper portion 6 a of diameter substantially equal to the inner diameter of the unexpandedtubular element 2 and a conicallower portion 6 b of diametrical size adapted to expand thetubular element 2 to the desired diameter to form a liner in thewellbore 3. Thetubular element 2 is suspended on theprimary expander 6 whereby thecylindrical portion 6 a thereof extends into the lower end of thetubular element 2. - The
assembly 1 furthermore comprises abottom plug 10 arranged below theprimary expander 6 and connected to aplug mandrel 12 in releasable manner, the plug mandrel being fixedly connected to the lower end of theexpansion mandrel 8. Theplug mandrel 12, theexpansion mandrel 8 and the drill string have acommon fluid channel 13 for fluid pumped from surface to thebottom plug 10. Thebottom plug 10 comprises aflange 14 having arecess 16 into which alower end part 18 of theplug mandrel 12 fits. Therecess 16 andlower end part 18 have complementary hexagonal shapes so as to allow torque to be transmitted between theplug mandrel 12 and thebottom plug 10, however any other suitable shape may be selected to allow torque to be transmitted. A radially expandable tubularclad element 20 is fixedly connected to theflange 14 and extends coaxially around theplug mandrel 12. Asecondary expander 22 is arranged inside theclad element 20, the secondary expander having a cylindricalupper portion 22 a of diameter substantially equal to the inner diameter of the unexpandedclad element 20 and a conicallower portion 22 b of maximum diameter adapted to expand theclad element 20 against the inner surface oftubular element 2 after radial expansion thereof. Theclad element 20 has a launcher section in the form of thin walledlower section 24 with an oversized inner diameter to accommodate the conicallower portion 22 b of the secondary expander. The clad element further includes alower anchoring section 26, anupper anchoring section 28 axially spaced from the lower anchoring section, and asealing section 30 located between the lower andupper anchoring sections section section 30 is at the outer surface provided withannular seals 34. - The
plug mandrel 12 extends through acentral bore 36 of thesecondary expander 22 in a manner allowing thesecondary expander 22 to slide in axial direction along theplug mandrel 12. Theplug mandrel 12 is provided withflow ports 38 fluidly connecting thefluid channel 13 with afluid chamber 40 formed between the large diameter end of thesecondary expander 22 and theflange 14. Initially the axial size of thefluid chamber 40 is very small but increases during expansion of theclad element 20 as will be explained hereinafter. The upper end of theclad element 20 is covered by aremovable debris cap 42 having acentral bore 44 through which theplug mandrel 12 extends in a manner allowing thedebris cap 42 to slide in axial direction along theplug mandrel 12. Thedebris cap 42 serves to prevent debris entering theclad element 20 prior to radial expansion thereof. Further, thebottom plug 10 is provided with areamer 45 having outlet openings in the form ofnozzles 46 in fluid communication with thefluid channel 13 via aninternal chamber 47 of the reamer and abore 48 in theflange 14. Thechamber 47 has a wall section of reduced thickness in the form ofburst plate 49 that is adapted to shear off at a selected fluid overpressure in thechamber 47 relative to a fluid pressure in the borehole i.e. exterior of thebottom plug 10. When sheared off, theburst plate 47 leaves a fluid outlet from the chamber with a flow area larger than the flow area of eachnozzle 46. Thebore 48 has aseat 50 for receiving a trailing plug 52 (FIG. 2 ) to close the bore. -
FIG. 2 shows theassembly 1 whereby afluidic cement column 53 surrounds thetubular element 2 and theassembly 1. The trailingplug 52 is received on the seat of thebore 48 and thereby closes the bore. -
FIG. 3 shows theassembly 1 after alower portion 54 of thetubular element 2 has been expanded by theprimary expander 6, whereby thebottom plug 10 is positioned in the expandedlower portion 54 and theclad element 20 is partly expanded against the inner surface of the expandedlower portion 54. A volume ofhydraulic fluid 56, such as spacer fluid or drilling fluid, has been pumped into thefluid chamber 40 via thefluid channel 13 andflow ports 38. -
FIG. 4 shows theassembly 1 after theclad element 20 has been fully expanded against the inner surface of the expandedlower portion 54 of thetubular element 2, whereby theplug mandrel 12 is released from theflange 14. Thesecondary expander 22 and thedebris cap 42 maintain positioned at the plug mandrel. -
FIG. 5 shows theassembly 1 aftertubular element 2 has been fully expanded, and theexpansion mandrel 8 and theplug mandrel 12 together with thesecondary expander 22 and thedebris cap 42 have been removed from thewellbore 3. Adrill string 58 with a polycrystalline diamond compact (PDC) bit 60 is lowered into the expandedtubular element 2 to drill out the remainder of thebottom plug 10. Instead of thePDC bit 60, a dedicated milling tool may be applied to drill out the remainder of the bottom plug. -
FIG. 6 shows a modifiedbottom plug 64 which is substantially similar to thebottom plug 10 except regarding the following. Thereamer 45 has anose section 66 arranged eccentrically relative to a central longitudinal axis of theplug mandrel 12. Furthermore, the modifiedbottom plug 64 is provided with anactivation sleeve 68 positioned in thebore 48 to temporarily close theflow ports 38. Theactivation sleeve 68 is locked in place by suitable shear pins (not shown) and is adapted to slide axially downward through thebore 48 when the shear pins are broken whereby theflow ports 38 are freed. Theseat 50 for the trailingplug 52 is provided in theactivation sleeve 68 rather than in thebore 48. Furthermore, the modifiedbottom plug 64 is provided with aprotective sleeve 70 extending around the sealingsection 30 and the anchoringsections clad element 20. Thesleeve 70 is fixedly connected to thedebris cap 42, the latter having a cylindrical part 42 a that extends into theclad element 20 and abuts against thesecondary expander 22.Reamer 45,flange 14 andclad element 20 are interconnected by a crossover sub 71. -
FIGS. 7a to 7d show anassembly 80 using a second embodiment of the shoe of the invention, wherebyFIG. 7a shows a side view andFIGS. 7b-d show a longitudinal section of the assembly. Theassembly 80 includes ashoe 82 connected to the lower end of a wellbore casing (or liner) 84. Theshoe 82 is provided with areamer 86 having aneccentric nose section 87 relative to a central longitudinal axis of thecasing 84. Thereamer 86 is provided with nozzles in the form offlow ports 88 to enable drilling fluid to be circulated during running into a wellbore. The size of theflow ports 88 is such that the total flow area of theflow ports 88 is similar to, for example, the flow area of a conventional PDC drill bit i.e. typically less than 1 square inch so as to provide the necessary jetting action for hole cleaning purposes. Theflow ports 88 are arranged such that an optimum flow distribution and scavenging of the wellbore by jet action is obtained. The inner surfaces of the flow ports may be provided with a hard facing to mitigate erosion during circulation. - The
reamer 86 is at its outer surface provided with a plurality ofcutter blades 90 having abrasionresistant cutting elements 92 e.g. carbides that may be brazed on the outer surface of the reamer. Thereamer 86 is connected to thecasing 84 by means of acrossover sub 94 which forms the transition between thecasing 84 and aflange 96 of theshoe 82. Theflange 96 is provided with a profiledbore 98 having aseat 99 for receiving a trailing plug 102 (FIG. 7d ) used during pumping cement into the wellbore. Thebore 98 is in fluid communication with theflow ports 88 via achamber 103 formed in the shoe. Agroove 104 is provided in thebore 98 to enable the trailingplug 102 to be locked in place once seated (FIG. 7d ). Theflange 96 may optionally be provided with radial ribs (not shown) that are surrounded by cement after cementation to prevent rotation of theflange 96 during drilling out the shoe from the wellbore. Further, theflange 96 may optionally be provided with arms (not shown) connected to thereamer 86 to provide mechanical support to the reamer. Thereamer 86 has a section of reduced wall thickness in the form ofburst plate 108 that is adapted to shear off from the reamer at a selected fluid overpressure in thechamber 103 relative to a fluid pressure in the borehole i.e. exterior of theshoe 82. When sheared off, theburst plate 108 leaves anoutlet opening 109 ofchamber 103 with a flow area larger than the flow area of each flow port 88 (FIG. 7c ). - Normal operation of the
assembly 1 is as follows. Theassembly 1 is lowered into thewellbore 3 on drill string and may be rotated to ream sections of thewellbore 3 byreamer 45. Simultaneously drilling fluid may be pumped into the wellbore viafluid channel 13,chamber 47 andnozzles 46. The pumped fluid assists in reaming the wellbore and transports rock particles to surface. Once theassembly 1 has reached target depth of the wellbore, thetubular element 2 is at its upper end anchored in thewellbore 3. Subsequently a volume of leading spacer fluid (not shown) is pumped into the wellbore via thefluid channel 13 to clean the fluid channel from drilling fluid, followed by thefluidic cement column 53 and the trailing spacer fluid 56 (FIG. 3 ). Instead of trailing spacer fluid, drilling fluid may be used. The leading spacer fluid and thefluidic cement 53 may be separated by a foam ball that crushes upon arriving in thebore 48 of thebottom plug 10 and is released through theoutlet openings 46. The fluidic cement and the trailingspacer fluid 56 are separated by the trailingplug 52 that seats on theseat 50 upon arriving in thebore 48. Thus, at this stage the trailingspacer fluid 56 is present in thefluid channel 13, and the cement column surrounds thebottom plug 10 and thetubular element 2. The trailingplug 52 closes thebore 48 and thereby seals thefluid channel 13 from the annular space around theassembly 1 in thewellbore 3. Theprimary expander 6 abuts against the lower end of thetubular element 2 therefore fluidic cement cannot enter the tubular element 2 (FIG. 2 ). - In the event that one or more of the
nozzles 46 become clogged before thefluidic cement column 53 has been fully pumped into the wellbore, the fluid pressure inchamber 47 increases as pumping continues until theburst plate 49 shears off upon the fluid pressure reaching the selected overpressure. Thereby, the relatively large flow area in the wall section of the former burst plate becomes available for pumping cement into the wellbore. In this manner theburst plate 49 forms a contingency device that prevents a catastrophic situation whereby the cementing procedure cannot be completed successfully. - The
burst plate 49 also protects thereamer 45 against pressure shockwaves that may occur in thefluid channel 13, for example during setting of a liner hanger or the activation of the expansion system. Such shockwaves may have amplitudes up to 3500 psi and will almost entirely reflect against thereamer 45 thereby doubling in amplitude. Theburst plate 49 shears off at such high pressure peaks and thereby protects thereamer 45 against damage or failure. - Furthermore, debris that may be present in the
bore 48 is pushed into thechamber 47 by the trailingplug 52 as it moves into thebore 48. In this manner proper seating of the trailingplug 52 in the bore is not hampered by such debris. - After seating of the trailing
plug 52 in thebore 48, theprimary expander 6 is pulled into thetubular element 2 by pulling the drill string whereby thelower portion 54 of thetubular element 2 is expanded (FIG. 3 ). Expansion is proceeded until the bottom 10 plug is fully inside the expandedlower portion 54. While maintaining the drill string under tension, fluid pressure is applied in thefluid channel 13 so that the trailingspacer fluid 56 flows via theflow ports 38 of theplug mandrel 12 into thefluid chamber 40. Thesecondary expander 22 thereby slides along theplug mandrel 12 away from theflange 14 and gradually expands the cladelement 20 against the expandedlower portion 54 of thetubular element 2. Thelower anchoring section 26 first engages the expandedlower portion 54, followed by the sealingsection 30 and subsequently theupper anchoring section 28. Upon the sealingsection 30 engaging the expandedlower portion 54, thetubular element 2 is simultaneously further expanded with theprimary expander 6 to maintain volume balance in the expanded section of thetubular element 2 between thebottom plug 10 and theprimary expander 6. - Once the
clad element 20 is fully expanded against the expandedtubular element 2, thesecondary expander 22 moves out of the clad element and thereby pushes thedebris cap 42 off theclad element 20. The interior of the expanded cladelement 20 is then filled with trailing spacer fluid that may be contaminated with cement. In a subsequent step the remainder of thetubular element 2 is expanded with theprimary expander 6 whereby thesecondary expander 22 and thedebris cap 42 are carried out of thewellbore 3 on the plug mandrel 12 (FIG. 4 ). After thebottom plug 10 has been set in the expandedlower portion 54 of the tubular element, fluid pressure can be applied below theprimary expander 6 via thefluid channel 13 to provide additional upward force to the primary expander 6 (hydraulic assist). Alternatively, the entire expansion force required to expand thetubular element 2 may be provided by such fluid pressure i.e. without applying tensile force to the drill string. - The design functionalities of the upper and
lower anchoring sections section 30 are as follows. When the fluid pressure in the interior space of the fully expanded cladelement 20 is higher than the fluid pressure below thebottom plug 10, the clad element is subjected to balloon deformation whereby thelower anchoring section 26 becomes firmly pressed against the expandedtubular element 2. Conversely, when the fluid pressure below thebottom plug 10 is higher than the fluid pressure in the interior space of the fully expanded cladelement 20, for example due to swab pressure below theprimary expander 6 during expansion of thetubular element 2, the clad element is subjected to balloon deformation whereby theupper anchoring section 28 becomes firmly pressed against the expandedtubular element 2. - After the cement has fully cured, the
bottom plug 10 is drilled out with thePDC bit 60 or milling tool ondrill string 58 whereby the bottom plug is supported by thecement 53 surrounding it (FIG. 5 ). - In a variation of normal use, the
cement 53 is pumped into the wellbore after thelower portion 54 of the tubular element has been expanded and thebottom plug 10 has been pulled into the expandedlower portion 54. This approach may be followed if there is a risk that thesecondary expander 22 is activated before thebottom plug 1 is inside thelower portion 54 of the tubular element, e.g. due to pressure waves in thefluid channel 13 propagating into thefluid chamber 40 during pumping of cement into the wellbore. However since in the alternative method there is reduced annular space between the expandedlower portion 54 of the tubular element and the wellbore wall, the pressure drop required to pump the cement at a certain rate through the annular space increases, which may lead to an increased risk of formation fracturing in critical pressure regimes. - Stabilization of the PDC bit or
milling tool 60 during drilling-out of thebottom plug 10 may be optimized as follows. In the methods described above theclad element 20 is hydraulically expanded with the trailingspacer fluid 56 as a pressure medium. Consequently after completion of the expansion process the interior of theclad element 20 is filled with trailing spacer fluid that may be contaminated with some cement. In order to optimize stabilization of the PDC bit ormilling tool 60 during drilling-out of the bottom plug 10 an additional volume of cement may be pumped behind the trailingplug 52 to expand theclad element 20. A trailing foam ball (not shown) may be pumped behind the cement, optionally followed by trailing spacer fluid. After the trailingplug 52 has seated in thebore 48, the installation process is continued as described above whereby the pressure medium used for the expansion of theclad element 20 is cement rather than trailing spacer fluid or drilling fluid. During expansion of thetubular element 2 the trailing foam ball is pumped out of theplug mandrel 12 into the wellbore. Thus, after curing of the cement thebottom plug 10 is surrounded by cured cement, optionally with excess cured cement above theclad element 20 to mitigate the risk of damage to the PDC bit ormilling tool 60 upon tagging thebottom plug 10 and to provide optimum conditions for drilling-out of thebottom plug 10. - In addition to the above, the risk of damage to the cutters of the PDC bit or
milling tool 60 when tagging the top of theclad element 20 can be further mitigated by connecting a short pipe section (not shown) of a soft metal, for example copper, to the top of theclad element 20. The pipe section is subjected to plastic deformation due to loading by the PDC cutters thereby limiting the peak contact load and thus the risk of impact damage to the PDC cutters. - Normal operation of the
assembly 1 when provided with the modified bottom plug (FIG. 6 ) is substantially similar to normal operation described above. In addition theeccentric nose section 66 of thereamer 45 helps in preventing rotation of the reamer during drilling out thebottom plug 10 with thePDC bit 60 or the milling tool. Theactivation sleeve 68 prevents unintentional expansion of theclad element 20 by thesecondary expander 22 due to fluid pressure peaks in thefluid channel 13 before the trailingplug 52 has landed in the activation sleeve. As the trailingplug 52 lands into theactivation sleeve 68, the trailing plug pushes the activation sleeve downward whereby the shear pins 69 are broken and theflow ports 38 are freed. Furthermore, theprotective sleeve 70 protects the sealingsection 30 and the anchoringsections clad element 20. During expansion of theclad element 20, theprotective sleeve 70 moves in axial direction away from the cladelement 20 together with thedebris cap 42. In this manner optimum protection is provided to thesealing section 30 and the anchoringsections - Normal operation of the assembly 80 (
FIGS. 7a-d ) is as follows. Theshoe 82 is connected to the lower end of thecasing 84 and theassembly 80 is run into a wellbore (not shown). When an obstruction is encountered in the wellbore, e.g. ledges in a deviated hole, theassembly 80 may be rotated while moving down to enable thereamer 86 to overcome the obstruction. If debris has accumulated in the wellbore due to, for example, downward movement of the assembly in a deviated wellbore, drilling fluid may be circulated simultaneously via theflow ports 88 to remove such debris by jetting action. In case of mechanical hole stability problems, rock cavings that cannot be removed by jetting only may obstruct lowering of theassembly 80. In such case thecutter blades 90 cut the cavings into jettable chunks which are transported to surface by the circulating drilling fluid. Once the target depth of the open hole has been reached, a volume of cement is pumped into the wellbore via thebore 98, thechamber 103 and theflow ports 88. The cement fills up the annulus between the casing and the wellbore wall. Following the cement, the trailingplug 102 is pumped onto theseat 99 of the flange 96 (FIG. 7d ). An elastomer seal (not shown) at the outer surface of the trailing plug seals the trailing plug relative to thebore 98. Alock ring 110 of the trailing plug snaps into thegroove 104 so as to prevent the trailing plug from being pushed back by U-tubing pressure of the cement. Any debris that may be present in thebore 98 is pushed into thechamber 103 by the trailingplug 102 as the latter lands into thebore 98. - The relatively small size of the flow ports 88 (required to provide the necessary jetting capability during reaming) involves the risk of clogging of the
flow ports 88 during cementation. In case of such clogging (FIG. 7c ) the fluid pressure in thereamer 86 will increase until the pressure rating of theburst plate 108 is exceeded so that the burst plate shears off. Thereby a new flow port 112 with a flow area of some 2-3 square inches is provided which is typical for conventional cementing shoes. This enables the cementing operation to be completed successfully by pumping the remainder of the cement via the new flow port 112 into the annulus. - Once the cement is cured the
shoe 82 is drilled out preferable using a PDC drill bit. The components of theshoe 82 are bonded to the cured cement and therefore are locked in place during drilling out. For example, the ribs (if present) and thecutter blades 90 assist in such locking of the components. Further, theeccentric nose section 87 of thereamer 86 prevents rotation of the reamer with the drill bit. All components to be drilled out are suitably made from easily drillable material e.g. cast iron or aluminium, and the cutting elements on the cutting blades are of small size and are embedded in a relatively soft substrate such as brazing material. In this manner the hard cutting elements can easily be broken out of the substrate and discharged from the wellbore by the drilling fluid. - The present invention is not limited to the above-described embodiments thereof, wherein various modifications are conceivable within the scope of the appended claims. For instance, features of respective embodiments may be combined.
Claims (19)
1. A shoe for a tubular element in a borehole extending into an earth formation, the shoe comprising:
a body adapted to be connected to a downhole end of the tubular element, the body being provided with:
a fluid channel;
at least one nozzle for jetting fluid into the borehole, each nozzle being in fluid communication with the fluid channel and
an additional fluid outlet for pumping fluid from the fluid channel into the borehole, the fluid outlet being closed by a closure device arranged to open at a selected fluid overpressure in the fluid channel relative to a fluid pressure in the borehole;
characterized in that the additional fluid outlet has a flow area larger than each nozzle.
2. The shoe of claim 1 , wherein the closure device includes a section of reduced wall thickness of the body, which section is arranged to shear off from the body upon the fluid pressure in the fluid channel reaching the selected overpressure.
3. The shoe of claim 2 , wherein the section of reduced wall thickness comprises a burst plate.
4. The shoe of claim 1 , wherein the fluid outlet has a flow area between about 2 to 3 square inch (12 to 20 cm2).
5. The shoe of claim 1 , wherein the total flow area of said at least one nozzle is less than 1 square inch (6.5 cm2).
6. The shoe of claim 1 , wherein the fluid channel is provided with a seat for receiving a plug for closing the fluid channel.
7. The shoe of claim 6 , wherein the fluid channel is provided with locking means for locking the plug in the fluid channel.
8. The shoe of claim 7 , wherein the locking means comprises a recess formed in a selected one of the fluid channel and the plug, and wherein the other of the fluid channel and the plug is provided with a locking member arranged to snap into the recess upon the plug landing on the seat.
9. The shoe of claim 8 , wherein the recess comprises an annular groove formed in the fluid channel, and wherein the locking member comprises a lock ring provided to the plug.
10. The shoe of claim 6 , wherein the body is provided with a chamber arranged to receive debris from the fluid channel, and wherein the plug is adapted to move the debris from the fluid channel into the chamber.
11. The shoe of claim 1 , wherein the body includes a flange provided with at least one radially extending rib, each rib being arranged to prevent rotation of the flange during drilling-out of the shoe in the borehole.
12. The shoe of claim 1 , wherein the body includes a reamer for reaming the borehole during lowering of the tubular element into the borehole.
13. The shoe of claim 12 , wherein each nozzle is positioned at the reamer.
14. The shoe of claim 12 , wherein the reamer has a nose section arranged eccentrically relative to a central longitudinal axis of the tubular element when the shoe is connected to the tubular element.
15. The shoe of claim 12 , wherein the reamer is provided with at least one cutter blade for cutting rock particles during reaming of the borehole, each cutter blade being arranged to prevent rotation of the reamer during drilling-out of the shoe in the borehole.
16. The shoe of claim 1 , wherein the closure device comprises a section of reduced wall thickness of the body.
17. The shoe of claim 16 , wherein the section is arranged to shear off from the body upon fluid pressure in the fluid channel reducing the selected fluid overpressure.
18. The shoe of claim 16 , wherein the section comprises a burst plate.
19. The shoe of claim 16 , wherein the section of reduced wall thickness is integral part of the body.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
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EP14173875 | 2014-06-25 | ||
EP14173875.7 | 2014-06-25 | ||
PCT/EP2015/064273 WO2015197703A1 (en) | 2014-06-25 | 2015-06-24 | Shoe for a tubular element in a wellbore |
Publications (1)
Publication Number | Publication Date |
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US20170130536A1 true US20170130536A1 (en) | 2017-05-11 |
Family
ID=51133838
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US15/320,096 Abandoned US20170130536A1 (en) | 2014-06-25 | 2015-06-24 | Shoe for a tubular element in a wellbore |
Country Status (3)
Country | Link |
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US (1) | US20170130536A1 (en) |
AU (1) | AU2015279245C1 (en) |
WO (1) | WO2015197703A1 (en) |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
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US10435971B2 (en) | 2014-12-12 | 2019-10-08 | Shell Oil Company | Anchor system and method for use in a wellbore |
US10450845B2 (en) | 2014-12-12 | 2019-10-22 | Shell Oil Company | Expanding a tubular element in a wellbore |
CN111587312A (en) * | 2017-09-27 | 2020-08-25 | 阿布扎比国家石油公司 | Liner for a wellbore |
RU2746181C1 (en) * | 2020-08-11 | 2021-04-08 | Общество с ограниченной ответственностью "ГЕОПРОТЕК" | Column shoe with hydraulic drive |
US20230046556A1 (en) * | 2021-08-12 | 2023-02-16 | Saudi Arabian Oil Company | Off bottom cementing system |
RU2808164C1 (en) * | 2023-06-17 | 2023-11-24 | ОБЩЕСТВО С ОГРАНИЧЕННОЙ ОТВЕТСТВЕННОСТЬЮ "МАКСИМА Дриллинг" (ООО "МАКСИМА Дриллинг") | Hydraulic working base plate (options) |
EP4303396A1 (en) | 2022-07-06 | 2024-01-10 | Downhole Products Limited | Rasping shoe for non-rotational deployment of casing string |
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WO2015197705A2 (en) | 2014-06-25 | 2015-12-30 | Shell Internationale Research Maatschappij B.V. | Assembly and method for expanding a tubular element |
BR112016029819B1 (en) | 2014-06-25 | 2022-05-31 | Shell Internationale Research Maatschappij B.V. | System and method for creating a sealing tube connection in a wellbore |
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US10435971B2 (en) | 2014-12-12 | 2019-10-08 | Shell Oil Company | Anchor system and method for use in a wellbore |
US10450845B2 (en) | 2014-12-12 | 2019-10-22 | Shell Oil Company | Expanding a tubular element in a wellbore |
CN111587312A (en) * | 2017-09-27 | 2020-08-25 | 阿布扎比国家石油公司 | Liner for a wellbore |
RU2746181C1 (en) * | 2020-08-11 | 2021-04-08 | Общество с ограниченной ответственностью "ГЕОПРОТЕК" | Column shoe with hydraulic drive |
US20230046556A1 (en) * | 2021-08-12 | 2023-02-16 | Saudi Arabian Oil Company | Off bottom cementing system |
US11767734B2 (en) * | 2021-08-12 | 2023-09-26 | Saudi Arabian Oil Company | Off bottom cementing system |
EP4303396A1 (en) | 2022-07-06 | 2024-01-10 | Downhole Products Limited | Rasping shoe for non-rotational deployment of casing string |
RU2812388C1 (en) * | 2023-05-25 | 2024-01-30 | Публичное акционерное общество "Татнефть" имени В.Д.Шашина | Column shoe for horizontal shafts |
RU2808164C1 (en) * | 2023-06-17 | 2023-11-24 | ОБЩЕСТВО С ОГРАНИЧЕННОЙ ОТВЕТСТВЕННОСТЬЮ "МАКСИМА Дриллинг" (ООО "МАКСИМА Дриллинг") | Hydraulic working base plate (options) |
Also Published As
Publication number | Publication date |
---|---|
AU2015279245A1 (en) | 2016-12-08 |
WO2015197703A1 (en) | 2015-12-30 |
AU2015279245C1 (en) | 2018-10-04 |
AU2015279245B2 (en) | 2017-07-20 |
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