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
  • E21B33/00—Sealing or packing boreholes or wells
  • E21B33/10—Sealing or packing boreholes or wells in the borehole
  • E21B33/13—Methods or devices for cementing, for plugging holes, crevices or the like
  • E21B33/14—Methods or devices for cementing, for plugging holes, crevices or the like for cementing casings into boreholes
• • 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
  • E21B29/02—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 by explosives or by thermal or chemical means
• • 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
  • E21B43/11—Perforators; Permeators
• • 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
  • E21B33/13—Methods or devices for cementing, for plugging holes, crevices or the like
• • 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
  • E21B37/00—Methods or apparatus for cleaning boreholes or wells
• • 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
  • E21B43/11—Perforators; Permeators
  • E21B43/116—Gun or shaped-charge perforators
• • 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
  • E21B43/11—Perforators; Permeators
  • E21B43/116—Gun or shaped-charge perforators
  • E21B43/117—Shaped-charge perforators
• • 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
  • E21B43/11—Perforators; Permeators
  • E21B43/116—Gun or shaped-charge perforators
  • E21B43/1185—Ignition systems
• • 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
  • E21B43/11—Perforators; Permeators
  • E21B43/119—Details, e.g. for locating perforating place or direction
  • E21B43/1193—Dropping perforation guns after gun actuation

Definitions

• the present invention relates to the technical field of well intervention, wherein an inner casing is perforated without damaging a surrounding casing; an annulus cement about the perforated inner casing is disintegrated and washed out.
• the perforated, annulus-washed-out casing is cut and pulled out of hole, or the perforated, washed-out casing bore and annulus is cemented for sealing the second casing, first annulus.
• a combination of plug cementing and cutting and pulling the perforated washed-out inner casing is done.
• the cutting and pulling of the inner casing frees up space in the second casing above the cut.
• the annulus cementing may serve several purposes such as for temporary or permanent plugging and abandonment.
• Petroleum wells are lined with casing pipes extending from the surface, and liner pipes extending along parts of the well such as from a casing pipe's lower end.
• casings may be arranged with decreasing diameter within previously installed casing pipes along with the sinking of a well into the ground.
• a casing may be cemented to the surrounding borehole wall along critical points along the casing, such as in the upper portion, in the lower portion, and selected points along its length.
• a subsequent casing or liner may be cemented to the surrounding casing (or to the borehole wall) also at critical points in order to avoid leakage, or to stabilize the casing, or to isolate oil or gas producing zones, or to isolate from water-bearing zones.
• 1 annulus whether in the first or subsequent annuli, is designed to be leak-proof and to have excellent bonding to steel and / or the surrounding geological formation.
• cement we may interpret as a material which does not disintegrate or dissolve by liquid flow alone, and may comprise homogeneous cement; partly cracked cement; baryte, salt based deposits, calcium carbonate based deposits and the like; scaling; and hard packed particulate matter in the annulus.
• cement slurry It may be required to use cement slurry to plug the first annulus over a given section of the casing for several different reasons.
• the annulus about a casing to be cemented may already comprise a cement fill which may be imperfect, or simply too short. Official regulations for plugging and abandonment of a zone of a well may require 50 m of plug, while an existing plug in the annulus may have shorter extension and thus not be acceptable for the P&A purpose.
• annulus plug will then pose an obstacle to cementing the annulus over a desired, required new length, and should thus be removed in order to circulate in new cement slurry to form a new annulus barrier.
• a method of cementing the annulus is to perforate the casing, wash the casing annulus with a drill pipe string conveyed washing tool with swab cups, and cement the annulus via a stinger in the casing bore and allowing the cement to enter the annulus via the perforations, such as in the textbook Nelson et al.: "Well cementing" second edition, p. 529, Schlumberger, 2006.
• the perforation operation must be very carefully designed in order not do damage the second casing, so the cement in the first annulus is only locally perforated.
• NO20111641 describes a method similar to the above, wherein a casing is perforated using a perforation gun, the annulus washed out using a drill pipe string washing tool with swab cups which is left behind as a basis for the subsequent cementing, and cement is introduced via at least the drill pipe string in the central bore of the perforated, washed-out casing. According to NO20111641 cement may then enter the washed-out annulus for allowing to set.
• No20131131 Bakken describes a method of perforating a casing, washing out the annulus of which the perforations give access using a swab cup wash tool, and cementing the annulus by circulating in cement via the drill pipe string and the wash tool, preferably starting cementing at the bottom and utilizing by-pass lines within the wash tool to allow cement to fill the casing below the wash tool as it is being slowly pulled upwardly while pumping in cement to the annulus.
• US5775426 Snider et a I describes an apparatus and method for perforating and stimulating a subterranean formation.
• the apparatus comprises one or more explosive charges, a shell of propellant, the explosive charges being positioned within the shell of propellant; and a detonator ballistically connected to the one or more charges.
• the shell may be a cylindrical sleeve.
• the shell may be provided with at least one groove or channel in order to assist in uniformly breaking up.
• the propellant material may thus disintegrate or decompose upon detonation of the one or more charges.
• the propellant may be water repellant or water proof, and will not be affected physically by hydrostatic pressures in the well, and it may be non-reactive to well fluids.
• Snider The purpose of Snider is that the propellant material generate gases which clean the perforations formed in the formation by detonation of the shaped charges and which extend fluid communication between the formation and the well bore.
• making a fluid communication between the geological formation and the central casing bore would counteract the purpose of sealing the first annulus with cement, as the deep perforation could incur new communication paths around the cemented annulus.
• US patent US4253523 to Ibsen describes a primary explosive arranged in directional charges of long reach distributed along the cylindrical main body of a perforation gun.
• a secondary explosive with slower detonation properties than the primary charges is placed between the directional primary explosives.
• Such a slower detonating secondary explosive produces a prolonged blast and a desired fracturing of the formation around perforations made by the primary explosive charges.
• secondary explosive may be activated ammonium nitrate.
• a main purpose of Ibsen is to make deep perforations into the geological formation.
• US patent US7913761 to Pratt describes a method for perforating a subterranean formation including positioning a shaped charge and a reactant composite material in a carrier; positioning the carrier in the wellbore; detonating the shaped charge; and disintegrating the reactant composite material using a shock generated by the detonated shaped charge.
• the reactant composite material may be configured to disintegrate upon detonation of the shaped charge.
• the tool comprises a plurality of parallel columns of explosives and a detonation system configured to detonate the columns of explosives.
• the columns are arranged such that upon detonation, at least a portion of the Shockwave propagating in a direction outwardly from the tool from one column combines with at least a portion of the Shockwave propagating in a direction outwardly from the tool from another column to create a combined Shockwave of greater intensity than either of the Shockwaves which formed the combined Shockwave.
• WO2020256563A1 relates to a casing retrieval drill pipe string conveyed toolstring assembly for a well comprising one or more casings.
• Said toolstring assembly comprising: - a casing spear tool arranged for engaging an inner wall of said casing and lifting part of said casing out when severed; - a casing cutter tool arranged for cutting and severing said casing at a casing cutting target depth - a casing perforation punching tool arranged for perforating said casing - wash tool arranged for washing said casing's annulus through perforations made by said punching tool.
• US2020165896A1 describes a system for forming an upper plug in a well.
• BIZLEY D. Subsea P&A. Upstream, Energy Global. 2015.05.07 (as published on the internet 2018.04.24) describes a system and a method for plug and abandonment (P8iA) of wells.
• the method comprises the steps of: Step 1: Well has been TA'd, tubing has been cut and pulled, and a cast-iron bridge plug and packer have been installed.
• Step 2 The upper assembly - consisting of an isolation bushing, tubing-conveyed perforating guns, and a telescoping joint - are landed and latched into the packer.
• Step 3 The upper tubing is conveyed and the lower standard perforating guns are fired into the B annulus.
• Step 4 Circulation is established through the tubing, into the lower perforations, up the B annulus, out through the upper perforations, and back up the production annulus.
• the isolation bushing diverts flow to the return lines.
• Step 5 The binary plug is circulated into the B annulus. After waiting on the cement to harden, a mandatory pressure test is performed.
• Step 6 The upper tubing is conveyed, and the lower standard perforating guns are fired into the C annulus.
• Step 7 Circulation is established through the C annulus as with the B annulus before.
• Step 8 The binary plug is circulated into the C annulus. The plug is left in a 'balanced' condition with the production annulus. After waiting on the cement, testing is performed.
• Step 9 The upper assembly is unlatched from the packer and pulled from the well.
• a cast-iron bridge plug is set above the highest perforations and cement is bailed as per regulations. Wild Well advises customers to leave the well head intact.
• a main object of the present invention is to disclose a device and a method for removing the old, hardened cement in a casing annulus in order to conduct a cut-and pull
• the invention is a method of annulus cleaning an annulus- cemented (102) casing portion (CIO) of a first casing (Cl) in a second casing (C2) in a petroleum well, comprising the steps of:
• the invention also is a casing annulus cleaning tool string comprising - a drill pipe string (0) with
• said perforating gun (1) arranged with - first, shallow-perforating charges (11) for shooting first, shallow perforations (12) through said casing portion (CIO) into a first annulus (CIOA), said shallow-perforating charges (11) arranged for leaving a surrounding second casing (C2) intact;
• washing tool (3) arranged above said perforation gun (1) and cement shattering device (2) on said drill pipe string (0), said washing tool (3) for washing out said shattered cement (102) from said annulus (CIOA).
• the toolstring comprises a casing cutter tool (5) and a casing spear (6).
• said washing tool (3) is also arranged for circulating in cement slurry into said washed-out annulus (CIOA) for sealing said annulus (CIOA).
• washing tool (3) arranged together with the perforation gun (1) and the cement shattering device (2) on the same drill pipe string, but strictly, they may be arranged as two separate tools run sequentially; the first tool comprising the perforation gun (1) and the cement shattering device (2) run on one string, and the washing tool (3) run on another drill pipe string, but running all tools on the same string is highly advantageous due to the time saved on the intervention rig. Further; it is advantageous running the cementing on the same run as the washing-out of the annulus because then there is less time for material to settle and lock in the first casing in the annulus.
• a swivel, a casing cutter tool (5) and a casing spear (6) integrated in the toolstring in order to conduct all operations in one run, or in two runs if it is desirable to remove the wash tool and casing cutter tool from the toostring before using the spear.
• the spear is still useful if swivelled and applied during the cutting operation, so it may be integrated in the toolstring from the beginning. Please see Fig. 6c, Fig. 6d, and Fig. 12.
• Fig. 1 illustrates a well with a first and a second casing (Cl, C2) , wherein the first casing (Cl) is cemented (101) or otherwise fixed in part of or all of the first annulus (Al) along a part (CIOA) outside a casing portion (CIO) of the first casing's (Cl) extent.
• the first casing (Cl) is surrounded along part or all of its length by said second casing (C2).
• the casing (Cl) annulus (CIOA) shall according to the invention be cleaned out of the previous partial or complete cement and sealed with new cement, without damaging the second casing or its surrounding second annulus cement.
• FIG. 2a is an illustration of the perforation gun (1) firing through a desired section; casing portion (CIO) of the first casing (Cl), while leaving the second casing (C2) generally intact.
• Fig.2a further shows:
• FIG. 2b is an illustration of an embodiment of the invention wherein the perforation gun (1) is combined with a shattering tool (2); the perforation gun (1) fires and makes perforations (12) through the wall of the first casing (Cl) making a perforated casing portion (CIO). In the embodiment illustrated it fires through the shattering tool (2) portion of the combined tool, a cylindrical sleeve (211), and brings along second charge fragments (21F) from the cylindrical sleeve (211) through the perforations (12). Further Fig.2b shows:
• FIG. 3a is an illustration of a shatterer device (2), in the embodiment of a second gun (20), has been pulled upwardly to the perforated casing section (CIO). The second gun (20) is triggered. This incurs shattering of the first annulus' (CIOA) cement (101), and partially releases the cement from the inner and outer casings (Cl, C2). Please also see Fig. 10.
• CIOA first annulus'
• FIG.3a shows:
• FIG. 3b is an illustration of a shatterer device (2) in the embodiment of a combined perforation gun (2) with a second charge (211) being ignited by the perforation charges and creates charge fragments (21F) which generate heat in the first annulus (CIOA) and within the casing. Please also see Fig. 13.
• FIG. 4 illustrates the tool string with the washing tool (3) run further into the casing so as for aligning the wash tool (3) with the perforated, annulus cement shattered casing section (CIO).
• the wash tool (3) is aligned with the upper portion of the perforated casing section (10), and washes out the annulus (CIOA) while being moved downwardly towards the bottom of the perforated casing section. This effectively removes shattered cement debris from the annulus (CIOA) and thus prepares the annulus for being cemented.
• the perforation and/or shattering tool (1, 2) tool may be disconnected from the washing tool (3) using an ordinary ball-release sub below the washing tool (3) and the perforation tool (1). This is advantageous both due to operational safety, personal safety, and operation of ease. Further Fig. 4 shows:
• Fig. 5 illustrates the resulting washed-out annulus (CIOA) along the perforated casing section (CIO).
• FIG. 5 shows
• Fig. 6a shows the generally washed-out casing section (CIO) annulus engaged
• Fig. 6a further shows:
• Fig. 6b illustrates the wash tool having cemented the entire annulus up to the upper portion of the washed-out, now cement slurry filled annulus (CIOA).
• the illustrated length of perforated, washed-out, now cement slurry filled annulus (CIOA) is far longer in reality than illustrated here and may be 50 metres or more in order to provide a regulatory required length of cement sealed annulus.
• Fig. 6b further shows: - Cementing bottoms up
• Fig. 6c illustrates an embodiment wherein after washing out the annulus (CIOA), the casing cutter tool (5) is activated and rotates to cut off the casing (Cl) without cutting the second casing (C2). The cut is made in the washed-free casing section (CIO) which should now be free of cement in the annulus (CIOA). The cut may be made after the step of Fig. 6b wherein a cement plug is formed across part of the washed-out annulus (CIOA) below the cut to be made, or conducted without any cement plug.
• CIOA washed-out annulus
• Fig. 6c further shows:
• Fig. 6d illustrates the further step after the cut is made in Fig. 6c, wherein the casing spear (6) has been moved to an upper portion of the cut-off section of casing
• Fig. 6d further shows:
• Fig. 7 illustrates the resulting plug sealing the annulus and the casing bore.
• the cement slurry also in the casing bore may allow to settle and harden so as for plugging and abandoning the well below the plug.
• the cement slurry in the casing bore may be circulated out of the casing bore, (usually with reverse circulating).
• Fig. 7 further shows:
• FIG. 8 is, in the upper half, Fig. 8a, an illustration of a cross section of the first perforation gun (1) perforating shallowly and only through the first casing (Cl), leaving the second casing (C2) generally intact.
• Fig. 8b is illustrated the same position along the well, the same part of the perforated section (CIO) wherein is fired the higher-energy slow-burning charges (21) of the shatterer device (2), the second gun (20). The result is illustrated in Fig. 10 below.
• Fig. 8c illustrates the same vertical sections of the same perforation gun (1) and shatterer device (2) with very short delay.
• the upper part illustrates an embodiment of the perforation gun (1) combined with a shatterer device (2) constituting one combined perforation and shatterer tool (1, 2), wherein the perforation gun fires shallow perforations (12) through the first casing (Cl), and carries fragments (21F) of a second charge (21) through the perforations (12) and into the first annulus (Al).
• the lower part is illustrated the same tool section a few milliseconds later, the situation after the perforation charges have set off, wherein the slower-burning charges 21F have spread, and ignite and combust.
• Fig. 8c further shows:
• Fig. 9 is a photographic image of an ordinarily perforated dual casing with
• Fig.9 further shows:
• Fig. 10 is a photographic image of a perforated and shattered cement according to the invention.
• Fig. 10 further shows:
• Dual casing perforated and treated according to the present invention Shallow perforations through inner casing (Cl), and shot using second, slow-burning, energy rich charges which have broken up the first cement (101) between the perforation holes. We see that the cement is broken up and easily disintegrates.
• Fig. 11 is also a photographic image corresponding to Fig. 10, with the shattered cement picked away and removed from the annulus within the second casing. Fig. 11 further shows: - Having removed the inner casing (Cl) (for demonstrating the effect) from the annulus cement (101) broken up according to the invention: The cement is easily plucked away. This shows that a wash tool in the casing (1) may easily wash out the broken up cement (101) in the annulus (CIOA) [0044]
• Fig. 12 illustrates an embodiment of the invention wherein the perforation gun and the shattering gun are combined in one common gun tool (1, 2), and further combined with a wash tool above, and a drill pipe string (0). Also shown is the embodiment wherein there is further included a swivel (3S), a casing cutter tool (5), and a casing stinger (6).
• 3S swivel
• Fig. 13 shows an embodiment of the invention also illustrated with details in Fig. 8c, and which is also illustrated in use in Fig. 3b.
• said shatter tool's (2) slow-burning higher-energy charges (21) is arranged as a sleeve-shaped layer outside on and in combination with said perforation gun's (1) shallow-penetrating charges (11).
• a wash tool (3) is combined with this combined perforation and shatter tool (1, 2) and the entire tool is arranged for being run on a drill pipe string (0).
• the invention is a method of cleaning an annulus- cemented (102) casing portion (CIO) of a first casing (Cl) in a second casing (C2) in a petroleum well, comprising the steps of:
• the present invention is highly advantageous over prior art which is not capable of perforating the inner casing only and shattering only the cement in the inner casing's annulus without damaging the second casing.
• Prior art such as US2003/0037692 Liu fires charges indiscriminately through the casing, through cement, and far into the surrounding geological formation and injects sluminium powder to burn out the deep rock perforations, and to react with water in the formation to further combust.
• US2007/0095529 Bond describes shaped charges that forces oxygen-rich material into deep rock perforations to combust with oil in the geological formations.
• the present invention provides a far gentler method of penetrating only the first, inner casing, and
• the method comprises
• the casing spear tool (6) is advantageously in an embodiment arranged at the top of the toolstring BHA in order to have a good tensile strength margin throughout the DP string (0) and the casing spear tool (6) in order to pull out the casing.
• the washing tool (3), the swivel (3S), and the cutter tool (5) may in an embodiment of the invention be removed from the toolstring before engaging the casing stinger (6) in the top of the cut-off casing section to be pulled, in order to facilitate the tripping out.
• the AGR (8) has dropped the guns (2) after firing, anyway, we don't want misfired gun charges to the deck.
• a cementing tool (7) we run a cementing tool (7) and circulate in cement slurry (c) into at least said washed-out annulus (CIOA) around said perforated casing portion (CIO) of said well for sealing said annulus (CIOA). This is done before a cut and pull operation described above, or instead of a cut and pull operation if the purpose is just to cement the first annulus between the inner and second casing (Cl, C2).
• the annulus cement shattering device (2, 20) may in one embodiment be a tool arranged separate from and below the perforation tool (1), please see Fig. 2a, Fig. 3a, Fig. 4, Fig. 5, Fig. 8a, and Fig. 8b, and thus has to be displaced to the perforations (12) made by the perforating tool (1) before the annulus shattering device (2) is activated, such as defined in claims 2, 3, 4, and 5.
• the annulus cement shattering device (2) may in another embodiment be a tool extending along the same portion along the stem of the perforation tool (1) itself. The annulus cement shattering device (2, 20) may thus be embodied together with the
• the shattering tool (2) may have a brief delay of being activated after the firing of the perforation tool (1) in order to utilize the perforations (12) formed by the perforation tool (1), for "burning out” the perforations but also the annulus (CIOA) outside the perforations.
• the material in the annulus be old, hardened cement, but not necessarily cement; it may also comprise compacted debris, clay, and other particles which seal the first casing annulus in the borehole or in a subsequent casing so that it may not easily be perforated, washed and pulled, or perforated, washed and sealed, either for replacement pulling, or plug and abandon, or for sealing an annulus leakage.
• Not all the annulus length (CIOA) may necessarily comprise old cement or similar material preventing a good wash-out of the annulus, only part may be blocking.
• the old cement must be shattered, disintegrated and washed out before freeing the casing for cutting and pulling, or new cement slurry is circulated in to form a proper seal of required length.
• the perforated and washed-out casing portion (CIO) of the inner casing (Cl) may comprise a non-perforated part of any length above the perforated section (CIO).
• the length of the perforation gun (1) may be 50 to 100 metres or more, assembled screwed together from gun sections of lengths 6 1/2 m, 9 m, or other lengths.
• the length of the desired casing portion (CIO) to be perforated depends on the length of the cemented annulus to be cut and pulled, or the length of the cemented annulus to be sealed properly, a length of 50 m or more, which may be more than previously existing zonal isolation lengths.
• the length of the assembled shattering device (2) will most preferably be of the same length, particularly if it is assembled along the same stem length, as the assembled perforation gun itself. Having such extensive lengths of perforation gun and shattering device allows long lengths of casing to be perforated, shattered, washed-out, and cemented in one single trip.
• Fig. 1 illustrates a well with a first and a second casing (Cl, C2) , wherein the first casing (Cl) is cemented (101) with existing cement in the first annulus (Al) along a part (CIOA) outside a casing portion (CIO) of the first casing's (Cl) extent.
• the purpose is to free the first casing (Cl) from a second casing (C2) in order to pull it out of hole.
• the purpose is to cement the first casing portion (CIO) of the casing (Cl) and to leave the second casing (C2) and its second annulus cement (102) or other fill, if
• the second casing may be cemented (102) in what is called the second annulus (A2) to the borehole wall (BO) as illustrated, or to a third casing on the outside of the second casing.
• the inner casing may be a 9 5/8" pipe having a wall thickness of 15 mm or more.
• the second, outer casing may be a 13 3/8 pipe having a similar wall thickness.
• Other casing dimensions may of course apply.
• the first and second casings (Cl, C2) constitute part of the context of the present invention.
• Fig. 2a is an illustration of the perforation gun (1) firing through a desired section, a casing portion (CIO) of the first casing (Cl), while leaving the second casing (C2) intact with only minor scratches.
• Short-focus charges in the perforation gun (1) have the property of "punching" perforation holes through the first casing wall, and not through the second casing (C2) wall, which is left intact. But due to the perforations' relatively small charge and being geometrically focussed, only relatively narrow holes are made with short range, extending only into the concrete in the annulus (CIOA); no major shattering of the first annulus cement (101) occurs. This is also visible from Fig.
• the cement shattering device (2) comprises a second gun (20) with delayed, slow-burning charges (21) detonating in part via said first perforations into said perforated casing portion's (CIO) annulus (CIOA).
• the perforating gun (1) (above) and said cement shattering device (2) (below) are combined on the same drill pipe string (0), please se Figs. 2a and 3a.
• Fig. 3a is an illustration of a shatterer device (2), in the embodiment of a second gun (20), having been pulled upwardly to the perforated casing section (CIO).
• the length of the second gun (20) may be the same as the length of the first perforation gun (1).
• the second gun (20) may be triggered by a delay timer (22) initiated by the firing of the first perforation gun.
• the second gun (20) fires slower burning charges (21, 21s) (please
• Fig. 3a and Fig.8b which are also of higher energy than the first short-focus charges (11). It is not necessarily a perforation gun as such, as it fires/combusts and the fire gases are pressed into and through existing perforations. This incurs a shock wave and thermal energy which in combination results in shattering of the first annulus' (CIOA) cement (101) and shatters and burns it out, and partially releases the cement from the inner and outer casings (Cl, C2). Please also see the result in Fig. 10, wherein in Fig.
• the inner casing (Cl) (removed) of a dual casing is perforated and treated according to the present invention: Shallow perforations through inner casing (Cl), and shattered using second, slow-burning, energy rich charges which have broken up the first cement (101) between the perforation holes. We observe that the cement is broken up and easily disintegrates.
• This procedure using the delay timer trigger device (22) allows a certain time to activate the second gun (2), a delay which allows the pulling up to relocate the second gun (2) to where the first perforation gun (1) was fired.
• the perforation gun (1) and the shattering device (2) are combined in the same section of the tool, please see Fig. 8c.
• FIG. 17 first casing (Cl). Please see Figs. 4 and 5 below.
• An advantage of starting washing from the top of the perforated section (CIO) is that one will only wash out debris from an upper part of the shattered annulus (CIOA) cement debris initially, and may control the wash tool displacement speed downwardly according to how much cement debris is in suspension in the return flow at any time, a feature which is less controllable if one starts washing bottoms up of the shattered annulus, whereby one would run the risk of trying to lift too much debris at a time, risking blocking the wash tool from being pulled up in the casing.
• CIOA shattered annulus
• FIG. 4 illustrates the tool string with the washing tool (3) run further into the casing so as for aligning the wash tool (3) with the perforated, annulus cement shattered casing section (CIO).
• the wash tool (3) is aligned with the upper portion of the perforated casing section (10), and washes out the annulus (CIOA) while being run downwardly towards the bottom of the perforated casing section. This effectively removes shattered cement debris from the annulus (CIOA) and thus clears the annulus (CIOA) between the inner casing (Cl) from the outer casing (C2).
• Fig. 5 illustrates the resulting washed-out annulus (CIOA) along the perforated casing section (CIO).
• the perforating and shattering tools (1, 2) may have been used along a length of the casing section (Cl) longer than the perforating and shattering tools (1, 2), which may have been fired multiple times with relocation of the tools for each firing, but the washing process using the wash tool may be done in one continuous sequence while pumping from the surface through the drill pipe string (and possibly through a casing stinger and vibrator).
• the tool sequence may be as follows, please see Fig. 6: combining in sequence as illustrated in the attached drawings: - shattering tool (2) at the bottom of the string,
• the washing tool may be arranged with a through bore for supplying the wash tool with wash fluid, and with a ball passage for triggering the perforation gun (1), and requiring another ball diameter for closing the wash tool (3) in the bottom to direct the wash fluids, namely wash fluid, then spacer fluid, then cement slurry.
• Fig. 6a shows the generally washed-out casing section (CIO) annulus engaged the swab cups of the wash tool (3) near the lower perforations, while cement slurry is being pumped down via the conveying drill pipe string, out between the swab cups, and circulated without excessive force out into the washed-out, preferably spacer fluid primed annulus (CIOA) lower portion.
• CIO casing section
• CIOA spacer fluid primed annulus
• Fig. 6b illustrates the wash tool having cemented the entire annulus up to the upper portion of the washed-out, now cement slurry filled annulus (CIOA).
• the illustrated length of perforated, washed-out, now cement slurry filled annulus (CIOA) is far longer in reality than illustrated here and may be 50 metres or more in order to provide a regulatory required length of cement sealed annulus.
• Fig. 6c illustrates an embodiment wherein after washing out the annulus
• a casing cutter tool (5) is activated and rotates to cut off the casing (Cl) without cutting the second casing (C2).
• the cut is made in the washed-free casing section (CIO) which should now be free of cement in the annulus (CIOA).
• the cut may be made after the step of Fig. 6b wherein a cement plug is formed across part of the washed-out annulus (CIOA) below the cut to be made, or conducted without any cement plug.
• Fig. 6d illustrates the further step after the cut is made in Fig. 6c, wherein a casing spear (6) has been moved to an upper portion of the cut-off section of casing (Cl), and pulled out of hole.
• the perforation gun (1) is dropped after firing of the shattering device (2).
• An advantage of dropping the perforation gun (2) and the shattering device is possible.
• Fig. 7 illustrates the perforated, washed-out section (CIO) now plug cemented.
• FIG. 8 is, in the upper half, Fig. 8a, an illustration of a cross section of the first perforation gun (1) perforating shallowly and only through the first casing (Cl), leaving the second casing (C2) generally intact, usually with only minor radial deformation just outside the perforations formed.
• the shallow range perforation charges (11) are focussed onto the proximal casing wall (Cl), and do not focus on, nor perforating the second casing wall (C2).
• Fig. 8b is illustrated the same position of the casing along the well, the same part of the perforated section (CIO) wherein is fired the higher-energy slow-burning charges (21) of the shatterer device (2), the second gun (20).
• Fig. 8c illustrates an embodiment of the perforation gun (1) combined with a shatterer device (2) constituting one combined perforation and shatterer tool (1, 2).
• the shallow-range perforation charges (11) are triggered, usually by a common ignition cord (111), and perforate, shatter and ignite a surrounding layer comprising a second, slower burning explosive charge (21).
• the second charge (21) may comprise a cylindrical layer (211) which is fragmented into charge fragments (21F), please see the upper part of Fig. 8c.
• the charge fragments (21F) are partly brought along by the firing of the perforation charges (11) and brought out through the perforations (12) and end up in the annulus (Al). Partly, they remain as a partly or entirely shattered cylindrical layer (211) on the perforation gun.
• those fragments (21F) have been ignited by the energy release of the firing perforation charges (11) and burn slower, but release more energy than the perforation charges (11), into the cemented, now partly cracked up first annulus (Al).
• the energy release of the charge fragments (21F) further cracks up and disintegrates the cement in the first annulus and partly or entirely releases the cement from the first and second casing.
• the energy released from the now fragmented layer (211) within the first casing (Cl) in the tool's annulus will also contribute to the cracking up of the annular cement in the first annulus (Al).
• Fig. 9 is a photographic image with a laboratory experiment having run a perforation gun (1) of an ordinarily perforated dual casing (Cl, C2) with cement (101) inbetween, the image showing the inner casing (Cl) having been removed after perforation and splitting away of half of the dual casing. It is seen that the annulus
• Fig. 10 is a photographic image of a perforated and shattered cement according to the invention, here shown in a split outer casing, with the inner casing removed. It is seen that the cement is shattered and disintegrated.
• the dual casing (Cl, C2, and cement (101) is treated according to the present invention: Shallow perforations through inner casing (Cl), and the annulus cement (101) shattered using second, slow-burning, energy rich charges which have broken up and disintegrated the first cement (101) between the perforation holes.
• the perforated inner casing (Cl) is removed from the split setup, the cement is shattered broken up and easily disintegrates. This cement is feasibly washed out using standard wash tool techniques described in relation to Fig. 4 and Fig. 5.
• Fig. 11 is also a photographic image corresponding to Fig. 10, with the shattered cement picked away and removed from the annulus within the second casing. One will see that the perforations do not extend through the second casing.
• the removal of the shattered cement as conducted in this image is a purely mechanical removal which may be done by hand in the situation shown in the picture of Fig. 11, but the corresponding wash-out step as shown in Figs. 4 and 5 is done using a high pressure wash tool (3).
• the washing-out procedure may use a washing pressure of up to 1000 Bar or more on the drill pipe string holding the wash tool.
• the perforating charges are arranged in the tool stem and fire through a cylindrical surrounding layer of a second charge (211) which is slower-burning, but has a higher combustion energy than the perforation charges (11).
• the second charge (211) disintegrates into second charge fragments (21F) which are brought through the perforations (12) through the first casing (Cl) and combust to shatter and disintegrate the annular cement between the first and second casings (Cl, C2). In such an embodiment, there is no need for any delay firing device.

Landscapes

• Geology (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mining & Mineral Resources (AREA)
• Environmental & Geological Engineering (AREA)
• Fluid Mechanics (AREA)
• Physics & Mathematics (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Earth Drilling (AREA)
• Spinning Methods And Devices For Manufacturing Artificial Fibers (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=82404066

Family Applications (1)

Country Status (5)

Cited By (1)

Families Citing this family (2)

Citations (13)

Family Cites Families (15)

• 2021
  • 2021-05-11 NO NO20210594A patent/NO346353B1/no unknown
• 2022
  • 2022-05-11 WO PCT/NO2022/050105 patent/WO2022240295A1/en not_active Ceased
  • 2022-05-11 GB GB2206905.8A patent/GB2608264B/en active Active
  • 2022-05-11 US US18/290,411 patent/US12392217B2/en active Active
  • 2022-05-11 AU AU2022272595A patent/AU2022272595B2/en active Active

Patent Citations (13)

Non-Patent Citations (2)

Also Published As

Similar Documents

Legal Events