WO1995009966A1 - Method and apparatus for downhole activated wellbore completion - Google Patents
Method and apparatus for downhole activated wellbore completion Download PDFInfo
- Publication number
- WO1995009966A1 WO1995009966A1 PCT/US1993/009685 US9309685W WO9509966A1 WO 1995009966 A1 WO1995009966 A1 WO 1995009966A1 US 9309685 W US9309685 W US 9309685W WO 9509966 A1 WO9509966 A1 WO 9509966A1
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- WO
- WIPO (PCT)
- Prior art keywords
- pipe string
- borehole
- casing
- pipe
- pistons
- Prior art date
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Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP 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 DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP 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
Definitions
- This invention relates to completing a well traversing earth formation in a borehole and more particularly to detonating a fluid flow device by means of a pressure wave to open communication between casing pipe and an earth formation.
- the well In the process of establishing an oil or gas well, the well is typically provided with an arrangement for selectively excluding fluid communication with certain zones in the formation to avoid communication with undesirable fluids.
- a typical method of controlling the zones with which the well is in fluid communication is by running well casing down into the well and then sealing the annulus between the exterior of the casing and the walls of the wellbore with cement. Thereafter, the well casing and cement may be perforated at preselected locations by a perforating device or the like to establish a plurality of fluid flow paths between the pipe and the product bearing zones in the formation.
- the system comprises a piston for being mounted in an opening in the peripheral wall of the pipe and for extending generally radially outwardly from the pipe to contact the wall of the wellbore wherein the piston includes an explosive device therein.
- a deploying device deploys the piston from a retracted position which is generally within the maximum exterior profile of the pipe to an extended position wherein the piston extends generally radially from the opening to contact the wall of the wellbore.
- a detonation device is then positioned in the wellbore for detonating the explosive device in the piston while the piston is in its deployed position against the wall of the formation so as to perforate the formation by an explosive proximate to the formation.
- the piston when extended serves to center the pipe in the borehole and is substantially clear of the inner bore of the pipe to render the bore of the pipe full open.
- Figure 1 is a cross-sectional view of a wellbore traversing earth formations with a casing string arranged therein and spaced from the walls of the wellbore by a plurality of downhole activated pistons which are shown being activated to an extended position and which embody features of the present invention.
- Figure 2 is an enlarged cross-sectional end view of the casing taking along lines 2-2 in Figure 1, wherein the centralizers are shown extended to center the casing string in the wellbore.
- Figure 3 is a cross-sectional end view similar to
- Figure 4 is an enlarged cross-sectional view of a centralizer piston having a detonation device and shaped charge positioned therein, with the piston shown in a retracted or running-in position relative to the casing wall.
- Figure 5 is an enlarged cross-sectional view of the centralizer piston of Figure 4 in an extended position wherein the outer end of the piston is in contact with an earth formation.
- Figure 6 is a cross-sectional view of a wellbore showing a casing centralized in a borehole by pistons in an extended position and further showing a pressure wave generating device positioned in the casing by means of a pipe string.
- Figures 7 and 8 show cross-sectional views of a wellbore having an alternative system for producing a pressure wave in a casing string for detonating perforating charges.
- a wellbore W is shown having been drilled into the earth formations such as for the exploration and production of oil and gas.
- the illustrated wellbore W includes a generally vertical section A, a radial section B leading to a horizontal section C.
- the wellbore has penetrated several formations, one of which may be a hydrocarbon- bearing zone F.
- the wellbore W was drilled to include a horizontal section C which has a long span of contact with the formation F of interest, which may be a hydrocarbon-bearing zone. With a long span of contact within a pay zone, it is likely that more of the hydrocarbon present will be produced.
- there are adjacent zones which have fluids such as brine that may get into the production stream and thereafter have to be separated from the hydrocarbon fluids and disposed of at additional costs. Accordingly, fluid communication with such adjacent zones is preferably avoided.
- wellbores are typically cased and cemented and thereafter perforated along the pay zones.
- the casing tends to lay against the bottom wall of the wellbore, thereby preventing cement from encircling the casing and leaving a void for wellbore fluids such as brine to travel along the wellbore and enter the casing far from the formation from which it is produced.
- a casing string or liner 60 has been run therein which is spaced from the walls of the wellbore by a plurality of downhole activated pistons generally indicated by the number 50, which serve to centralize the casing.
- the downhole activated pistons or centralizers 50 are retracted into the casing 60 while it is being run into the wellbore as is illustrated by the centralizers 50 in Figure 1 which are ahead of an activator or pusher 82.
- the centralizers 50 are deployed to project outwardly from the casing as illustrated behind the activator or in Figure 1.
- the centralizers 50 move the casing from the walls of the wellbore if the casing 60 is laying against the wall or if the casing is within a predetermined proximity to the wall of the wellbore W. This movement away from the walls of the wellbore will thereby establish an annular free space around the casing 60.
- the centralizers 50 maintain the spacing between the casing 60 and the walls of the wellbore W while cement is injected into the annular free space to set the casing 60.
- the pistons are latched in an extended position and will thereby maintain the casing 60 centered even if the casing is not cemented.
- the centralizers 50 are better illustrated in Figures 2 and 3 wherein they are shown in the extended and retracted positions, respectively. Referring specifically to Figure 2, seven centralizers 50 are illustrated for supporting the casing 60 away from the walls of the wellbore W although only four are actually shown contacting the walls of the wellbore W. It should be recognized and understood that the centralizers work in a cooperative effort to centralize the casing 60 in the wellbore W. The placement of the centralizers 50 in the casing 60 may be arranged in any of a great variety of arrangements.
- the centralizers 50 be arranged to project outwardly from all sides of the periphery of the casing 60 so that the casing 60 may be lifted away from the walls of the wellbore W no matter the rotational angle of the casing 60. It is also preferred that the centralizers 50 be regularly spaced along the casing 60 so that the entire length of the casing 60 is centralized. The distance between centralizers and their radial orientation on the casing will vary depending upon the circumstances of a particular completion. For example, it is conceivable that the centralizers may be provided only in one radial orientation, or only at the ends of a section of casing. In Applicants' copending U.S.
- the centralizers 50 may present small bulbous portions 80 on the outside of the casing 60. It is preferable not to have any dimension projecting out from the casing to minimize drag and potential hangups while moving the string.
- the bulbous portions 80 are utilized in some embodiments especially in smaller diameter casings such is often used in horizontal holes when they are cased.
- the bulbous portions 80 are rounded to slide better along the walls of the wellbore and that the casing string 60 will include collar sections 90 that will extend out radially farther than the bulbous portion (see Figure 3) .
- the collar sections 90 present the maximum outer profile of the casing string even when the bulbous portions are present.
- the outward projection of the retracted centralizers 50 being within the maximum outer profile of the casing string 60 is believed to minimize any problems of running the casing.
- a deploying device or pusher 82 which moves from the top of the casing to its bottom end is shown positioned within the horizontal curved section B of the casing string.
- the deploying device 82 is sized to push the pistons 50 from a retracted to an extended position. It is noted that the centralizers or pistons 50 behind or to the left of the pusher 82 are in an extended position having been engaged by the tapered nose portion 85 of the pusher.
- the tapered portion 85 engages the inner ends of the pistons and pushes them outwardly as the piston travels until the body portion 83 has passed the piston whereupon the piston will be fully extended and locked into an extended position as will be hereinafter described.
- the centralizers in front of the pusher 82 are still in a retracted position and consequently the horizontal portion C of the casing in front of the pusher is shown lying on the bottom side of the borehole.
- the upper vertical section A and radial section B are shown centered in that the pistons 50 have been deployed to an extended position.
- the activator device shown in Figure 1 is a pumpable activator or deploying device having a tail pipe 81 which extends rearwardly from the main body portion 83 and seals the rear end of the device to the inside of the casing so that the device may be pushed down through the casing 60 by the application of hydraulic pressure.
- the activator may be run into the casing string on the end of a pipe string such as a drill pipe or coiled tubing wherein force is applied to the pipe string and thus to an activation device to engage and push out or extend the pistons 50.
- the centralizers or pistons may take many forms and shapes as is illustrated in Applicants' copending U.S. application Serial No. 07/761,210, incorporated herein by reference.
- the piston or centralizer 50 is shown in Figures 4 and 5 as including an explosive charge for perforating formations in the borehole.
- the centralizer 50 has a cylindrical or substantially cylindrical barrel portion or piston 12 which is slidably received in a bore in button 14.
- the button 14 is threadedly received within a tapped hole 16 which extends transversely through the wall of casing 60.
- a bulbous or rounded outer portion 80 extends outwardly slightly beyond the outside wall of the casing 60 but only to provide an adequate seat for the button 14 in thin wall smaller diameter casing and is constructed so that the outer extension of the bulbous portion 80 does not exceed the maximum profile of the pipe string which would normally be represented by the outside diameter of collars 90 in the casing string.
- the button 14 has a shoulder 17 formed at the base of the bulbous outer portion 80 that provides a surface for seating within a mating recessed surface at the outer end of the threaded hole 16 in the casing wall.
- the shoulder 17 forms a vertical surface on the button which fits against the mating vertical surface at the outer end of hole 16.
- An 0- ring 18 is arranged within a groove on the shoulder 17 to provide a seal between the shoulder 17 and a vertical face at the end of hole 16.
- the button 14 is arranged so that its inner end does not extend into the interior of the casing 60.
- the piston 12 is arranged for axial movement through the button 14 from a retracted position ( Figures 3 and 4) to an extended position ( Figures 2 and 5) .
- the piston 12 and the button 14 are mounted into casing 60 so that their axis are collinear and directed radially outwardly with respect to the axis of the casing 60.
- the piston 12 includes a plug 19 secured in an interior bore or passageway 18 in the piston by screw threads 22.
- An annular sealing ring 21 is positioned between the plug 19 and the inner end of piston 12.
- the piston 12 shown in Figures 4 and 5 also serves as a housing for a perforating device.
- the plug 19 is called an initiator plug in that it carries a device for initiating detonation of a shaped charge in the piston.
- the plug 19 does not fill the entire passageway 18 but is rather approximately the thickness of the casing 60.
- the plug 19 further includes a rounded inner end face 25 and a flat distal end face 24. The rounded surface 25 on the inner end of plug 19 is provided for facilitating the use of a deploying device to push the centralizer 50 into an extended position.
- the distal end 28 of the piston 12 may be chamfered or tapered inwardly to ease the installation of the piston 12 into the button 14.
- the piston 12 is mounted in a central bore in the button 14 which is preferably coaxial to the opening 16 in the casing 60 and is held in place by a snap ring 29.
- the snap ring 29 is located in a snap ring groove 31 milled in the wall of the interior bore of the button 14.
- Piston 12 includes two radial piston grooves 32 and 33 formed in the exterior cylindrical surface of the piston 12.
- the first of the two piston grooves is a circumferential securing or locking groove 32 which is positioned adjacent the inner end 27 of piston 12 to be engaged by the snap ring 29 when the piston is fully extended.
- the second of the two grooves is a circumferential retaining groove 33 positioned adjacent the distal end 28 of the cylinder 12 to be engaged by the snap ring 29 when the piston is in the retracted or running position as shown in Figure 4. As the piston 12 is illustrated in Figure 5 in the extended position, the snap ring 29 is engaged in the radial locking groove 32.
- the snap ring 29 is made of a strong resilient material arranged to expand into the snap ring groove 31 when forced outwardly and to collapse when unsupported into the grooves 32 and 33 when aligned therewith.
- the snap ring 29 is resilient as noted above so that it can be deflected deep into the snap ring groove 31 to slide along the exterior of the piston 12 and allow the piston 12 to move from the retracted position to the extended position.
- the snap ring 29 must also be strong to prevent the piston 12 from moving unless a sufficient activation force is applied to the piston 12 to deflect the snap ring 29 out of the retaining groove 33 into the snap ring groove 31 to permit the piston 12 to move through the snap ring to the extended position.
- the piston grooves 32 and 33 have a shape that in conjunction with the snap ring 29 allows the piston 12 to move in one direction but not the other.
- the snap ring 29 requires an activation or deploying force of a certain magnitude before it will permit the piston 12 to move.
- the magnitude of the activation or deploying force depends on the spring constant of the snap ring 29, the relevant frictional forces between the snap ring 29 and the piston 12, the shape of the piston groove, and other factors.
- a particular arrangement of snap ring and grooves is shown in greater detail in Applicants' copending U.S. Application Serial No. 08/051,032, incorporated herein by reference.
- the deploying method provides a deploying force on the inner end of each piston to overcome the resistance of the snap ring in the retaining groove 33 and cause the snap ring 29 to ride up and out of the retaining groove 33 whereupon the snap ring 29 is pushed up into the snap ring groove 31 within the button 14. This allows the piston to move out into the annular space of the wellbore. Once the piston encounters the wellbore wall, it will then lift the casing off of the wellbore to centralize the casing until such time as the snap ring 29 aligns with and expands into the locking groove 32.
- the pistons should be of such a length that the pistons can be fully deployed to the locking groove 32 while giving the maximum amount of centralization. Once the pistons are fully deployed, the inner surface 25 on the plug 19 will be substantially clear of the casing bore for all practical purposes, and the casing bore should be substantially full opened.
- the button 14 further includes a sealing arrangement to provide a pressure tight seal between the piston 12 and the button 14.
- the button 14 includes two 0-rings, 34 and 36, which are positioned on either side of the snap ring 29 in O-ring grooves 37 and 38, respectively.
- the O-rings 34 and 36 seal against the exterior of piston 12 to prevent fluids from passing from one side of the casing wall to the other through the bore of the button 14.
- the O-rings 34 and 36 must slide along the exterior of the piston 12 passing the piston grooves 32 and 33 while maintaining the pressure tight seal.
- the spacing of the O-rings 34 and 36 is such that as the piston 12 moves through the bore of the button 14 from the retracted position to the extended position, one of the O-rings 34 or 36 is in sealing contact with a smooth exterior surface of the piston 12 while the other may be opposed to one of the piston grooves 32 and 33.
- the piston 12 further includes an outwardly tapered enlarged diameter peripheral edge 39 on its inner end 27, which edge 39 is larger than the bore in button 14 that receives the piston 12.
- edge 39 serves as a stop against the button 14 to limit the outward movement of the piston 12.
- the inside face of button 14 includes a chamfered edge 41 for engaging the outwardly tapered peripheral edge 39 on the piston when the inner end 27 of the piston is approximately flush with the inner end face of the button 14.
- the inwardly facing rounded surface 25 of the initiator plug extends slightly into the bore of the casing for purposes to be described so that it is substantially clear of the bore to render the casing bore fully open to permit passage of the deploying device 82 or other similar device such as packers or the like that would be passed through the bore of a casing string.
- the centralizers 50 are initially arranged in the retracted position so that the casing 60 can be run into the well without the drag and interference of the centralizers 50 extending outwardly.
- the snap ring 29 is engaged within the retaining groove 33 to hold the piston in the retracted position until the piston 12 is moved outwardly.
- the pistons 12 are deployed to the extended position.
- a deploying arrangement as will be discussed below, provides a deploying force on the inner end of each piston 12 to overcome the resistance of the snap ring 29 in retaining groove 33 and cause the snap ring 29 to move into the snap ring groove 31 as the outer surface of piston 12 expands the snap ring outwardly.
- the deploying force further moves the piston 12 radially outwardly through the bore of button 14 so that the snap ring 29 rides over the outer surface of piston 12 to engage the locking groove 32 and thereby secure the piston in an extended position.
- the inner end of the piston and the rounded end face 25 of the initiator plug 19 are substantially clear of the casing bore to render the casing fully open for running tools or equipment therethrough.
- the term full open bore within the context of oil field terminology encompasses a situation such as the present wherein for all practical purposes equipment can be moved through the bore of a pipe unrestrictedly. In the present situation, the rounded end 25 of the plug 19 is designed to encroach into the bore approximately .14 inches.
- the casing 60 and centralizers 50 are selected based on the size of the wellbore W so that the pistons 12 may fully extend to the extended position and contact the borehole wall around most of the casing 60. Accordingly, during deployment of the piston 12 the deploying force is expected to move the piston 12 to its fully extended position wherein the snap ring 29 will snap into the securing groove 32 as the piston 12 moves to the fully extended position.
- the securing groove 32 has square edges so that the snap ring rides deep within the groove to prevent the snap ring from being expanded and thus to prevent the piston 12 from retracting back into the casing 60.
- the inner bore 18 of the piston 12 is shown having a shaped charge insert installed therein.
- the shaped charge insert includes a cup-shaped canister or carrier 46 which is sized to be press fit into the bore 18 of the piston 12.
- a locking compound is used to hold the canister 46 in the bore cavity of the piston.
- the carrier 46 is nested against a shoulder 47 in the piston bore 18, the shoulder 47 being the end of the threads 22 which are cut in the bore 18 of the piston at its inner end to receive plug 19.
- An ignition hole 48 is formed in the inner wall 49 of the cup-shaped carrier 46.
- a thin metal foil 51 is placed over the outer surface of hole 48 facing the plug 19.
- an outer end cap 54 is fitted within a recessed shoulder 55 and is held in place by its press fit and a locking compound.
- a shaped charge 58 is positioned in the canister 46 with a conical depression and metal liner 59 in the distal end of the face of the shaped charge facing outwardly.
- the opposite inner end of the piston 12 has the plug 19 enclosing the inner end.
- the plug 19 has a cylindrical recess 62 which is formed from the inner side of the plug 19 for receiving a detonator shell or cup 64.
- the shell 64 is held in place within the recess 62 by means of a thread locking compound press fit or the like.
- a recess 66 is formed in the outer wall surface 25 opposite the recess 62 on the interior of the plug 19.
- the recess 66 may be for example 3/16 inch in diameter and approximately .040 inches deep to leave an integral rupture disc portion 68 formed between the recesses 62 and 66.
- the rupture disc may be on the order of .0275 inches thick.
- the shell 64 which is assembled within the recess 62 has provided within its interior bore a detonating system which is comprised of an air space 70, a primary charge comprised of a layer of lead azide 72, and a base charge comprised of a layer of RDX explosive 74.
- Typical priming charges are of lead azide, lead styphanate, diazodinitrophenol, mercury fulminate and nitromannite. Mixtures of diazodinitrophenol potassium chlorate, nitromannite/diazodinitrophenol and lead azide/lead styphanate or a layer of a mixture of lead styphanate can be placed over lead azide.
- An alternative arrangement of rupture disc in Figure 5 includes a circular groove 61 formed inwardly into the plug 19 on either side of the disc 68.
- the rupture disc 68 is made thicker so as not to unnecessarily weaken the integrity of the barrier 68 that protects the detonator shell 64.
- the disc 68 will yield more predictably than by relying solely on normal yield of the metal between the recesses 66 and 62. This in turn provides initiation reliability to the pressure wave deto ition process.
- a thicker disc 68 can be provided between the recesses 66 and 62 to protect the detonator from inadvertent activation .
- movement of a piston activating or extending device 82 through the casing bore In Figure 5 of the drawings, the centralizing piston 12 is shown having been moved to an extended and locked position wherein the distal end 28 of the piston is in contact with the bore hole wall.
- a deploying device 82 such as is shown in Figure 1 has been moved through the interior bore of the casing string to contact the outer surface 25 of plug 19 on the inner end of the piston.
- the deploying device 82 passes the position in the casing string where the cylinder is positioned, the cylinder is forced outwardly with sufficient force to override the restraining effect of the snap ring 29 in the retaining groove 33.
- This overriding force causes the snap ring to move upwardly and expand outwardly into the groove 31 as it expands over the outer surface of the piston 12.
- the piston continues its movement until the tapered enlarged portion 39 on piston 12 abuts the mating chamfered surface 41 on the butto- 14 whereupon the piston 12 is positioned so that the snap ring 29 retracts into the locking groove 32 to hold the extended cylinder 12 in a predetermined fixed position.
- the deploying device 82 ( Figure 1) will have passed the extended piston 12 and proceeded downwardly through the casing string.
- the plug 19 at the inner end of the piston 12 is arranged so that it extends slightly into the interior bore of the casing string so that as the deploying device 82 passes the plug 19, the rounded surface 25 guides the deploying device past the plug 19.
- the plug 19 is of a material soft enough to be slightly deformed by the passage of the deploying plug and also is sized so that the rubber seal portion 81 at the rear of the deploying plug is deformable to a certain extent to permit its passage.
- the plug 19 is arranged so that the deformation of the curved outer surface 25 does not rupture the rupture disc portion 68 which is formed between the outer cavity 66 and the inner cavity 62 of the detonating device. It is also noted, that the explosive material 72 is spaced away from the end of the plug 19.
- the passage of the deploying device 82 through the interior bore of the casing 60 will not cause sufficient distortion of the plug 19 to bring the rupture disc 68 into contact with the explosive material 72.
- the perforating apparatus is now in a position to permit perforation of the formation which the wellbore traverses.
- the pistons 12 may be extended by the application of hydraulic pressure to the interior of the casing pipe string which provides a force that impinges on the inner end of the piston to move the pistons outwardly.
- one particular advantage of the apparatus described herein is that the centralizing piston and a button 14 which guides the piston, when provided, may be assembled within the casing string at some time just before the casing is run into the wellbore W. Accordingly, the handling of the casing pipe up to the point that it is being installed in the wellbore is not subjected to the danger which might be caused by having the explosive devices installed during shipping and handling of the casing prior to its installation. It is also to be noted that there is no device present within the system thus far described to initiate the explosive device within the piston so that such handling in the configuration described above is considered safe and will not unnecessarily endanger the personnel who are installing the devices in the casing or installing the casing within the wellbore.
- FIG. 6 of the drawings the casing 60 is shown having been run into a well.
- the centralizers are shown having been extended by means of a impable activator device 82 such as shown in Figure 1 or by the application of hydraulic pressure to the casing string at the surface. This is accomplished by clo ⁇ 'ng a valve at the base of the casing string and applying the necessary activation or deploying force required to move the pistons from the retracted position to the extended position. Accordingly, pumps or other pressure generating mechanism would provide the necessary deploying force for the pistons.
- an annulus of cement can be injected and set around the entire outer periphery of the casing, over some appropriate interval of casing, to seal the casing from the formation.
- the casing string with the centralizer system as described is arranged so that in those portions of the wellbore where it is desired to have a centralizing only function for the centralizers, the centralizers are not configured so as to provide a perforating function.
- the centralizers are of the embodiment shown in Figures 4 and 5 which include a shaped charge device or the like for perforating the formation to be produced.
- the centralizers which are not extended permit the casing to be rotated and reciprocated to work past tight spots or other interferences in the hole.
- These retracted centralizers 50 also do not interfere with the fluid path through the casing string so that fluids may be circulated through the casing to clear cuttings from the end of the casing string.
- the casing interior can be provided with fluids that are less dense than the wellbore fluids, in the annular space, causing the casing string to float.
- the centralizers 50 of the present invention permit a variety of methods for installing the casing into its desired location in the wellbore.
- the centralizers are deployed to centralize the casing. As discussed above, there are several methods of deploying the centralizers. Once the pistons are all deployed and the snap rings have secured them in the extended fixed position projecting outwardly toward the wall of the wellbore, the cement may be injected by well known techniques into the annulus formed by the centralizing of the casing within the borehole.
- the cement around casing 60 may be allowed to set while the production string is assembled and installed into the casing. It is important to note that at this point in the process of establishing the well, the casing and wellbore are sealed from the formation. Accordingly, there is as yet no problem with controlling the pressure of the formation or with loss of pressure control fluids into the formation.
- the perforation string is assembled to create perforations in the casing adjacent to the hydrocarbon bearing zone. Accordingly, high density fluids are provided in the wellbore and the production string to maintain a sufficient pressure head against the affect of formation pressure to avoid a blowout situation. While the production string is assembled and run into the well some of the wellbore fluids, in an overbalance condition, may be forced into the formation.
- the production string must be installed quickly to begin producing the well once the well has been perforated.
- the production string may be assembled and installed in the casing before the casing is opened and perforation of the formation is performed. If the production string is already in place in the well, adequate surface controls are already in place to prevent a blowout, so that the casing and production string can be in an underbalanced condition.
- production may begin when communication is established with the formation, such as by perforation. Accordingly, the well is brought on-line in a more controlled manner.
- Figure 6 shows an apparatus and system for initiating the detonators within the detonator shell 64 ( Figure 5) in the pistons, in order to fire the shaped charges and penetrate the formation.
- a small diameter pipe string such as production tubing 76 or coiled tubing is run into the interior of the casing string after the centralizers 50 are extended.
- the casing may or may not be cemented in place.
- a detonating cord 84 may be pre- installed in the lower end of the tubing string 76 and run into the well with the tubing string.
- the tubing string may be located in the casing string and then the detonating cord is run into the tubing string
- the bottom of the tubing string could be provided with a latching mechanism 93.
- a sinker bar with detonating cord trailing behind can be lowered into the tubing string and latched inside of the tubing.
- a device can be pumped to the latch 93 with a detonating cord trailing.
- a perforating head 89 would be run at the trailing, upper end of the detonating cord 84 to provide a means for initiating the detonating cord.
- the perforating head normally utilizes a detonator actuated by electrical, mechanical, or hydraulic means.
- a production packer 86 can be set.
- a sinker bar 91 can be dropped which would strike the perforating head and thereby initiate the detonating cord.
- a wireline can be used to operate the perforating head or otherwise initiate the detonating cord.
- Centering the pipe string 76 in the casing string may be important in view of the importance of propagating a pressure wave to the cylinders 12 on all sides so that the force of this pressure wave is sufficient to rupture the disc 68 in the plug 19.
- This rupture of disc 68 will sequentially initiate the powders 72 and 74 within the shell 64 positioned in the plug 19. Tests have shown that initiation of the detonator will take place without the provision of an air space 70 in the shell 64 by locating powders adjacent to the ruptured disc 68.
- the amount of pressure required to rupture the disc is increased when the air space is eliminated, so that the powder contacts the disc; however, detonation does take place.
- the principle behind the detonation is an adiabatic compression within the shell 64 which is sufficient to initiate the powders 72, 74 therein. Therefore, it appears to only be necessary to generate sufficient pressure within the interior of the casing bore to cause the ruptured disc 68 to rupture which will thereby initiate the detonator housed within the shell 64.
- initiation of the detonator is communicated through the opening 48 within the carrier 46 to detonate the shaped charge 58. This detonation produces a penetrating force that is directly applied to the formation F so that all the outwardly directed energy of the shaped charge is applied - to perforation and fracturing of the formation.
- the smaller diameter pipe 76 housing the detonating cord may be provided with slots or holes in the outside walls thereof to facilitate transmission of a pressure wave emanating from the detonating cord to the perforating cylinders 12.
- a pressure wave may be propagated through the walls of solid pipe which is sufficient to initiate the detonators within the plug 19 on the cylinders 12.
- the system shown in Figure 6 with a production packer 86 set in place will permit the completion to take place with an under-balanced fluid in the pipe string, so that upon perforation of the formation F formation, fluids may be readily received into the casing string through the now open cylinder 12 and from there into the production tubing 76 for conveyance to the surface.
- an alternative system for detonating the perforators includes a pumpdown arrangement for positioning a detonating cord within the interior of a casing string.
- An important feature of this centralizing and perforating system is that the perforators are not functionally armed when they are installed in the casing string, nor when they are positioned in the borehole, in that an initiating source is not provided. A means is thus provided for initiating the perforators after they are located within the wellbore.
- a detonating cord is again provided to generate a pressure wave which in turn ruptures the protective membrane or disc 68 on the end of the plug 19 within the perforating cylinder 12, with such rupturing of the membrane causing the detonator explosives to fire. Firing of the detonator explosives will initiate firing of the shaped charge.
- the detonating cord 104 is carried in a housing 94 which is attached to a displacement plug 96.
- the plug 96 may be pumped down behind cement being injected into the annulus to isolate the casing string from the formation.
- the detonating cord 104 is shown in Figure 7 coiled up within the housing 94 which is releasably attached to the pumpdown plug 96.
- the detonating cord 104 which is positioned within the housing and which is attached to the displacement plug 96 is then pulled out behind the upwardly moving housing 94 a sufficient distance to ensure that the detonating cord is positioned within the pipe string opposite the centralizer/perforators which are to be activated by a pressure wave.
- the upper end of the detonating cord is attached within the housing 94 to an electrically operated detonator (not shown) on the end of the electric wireline 98.
- Firing of the detonating cord generates a pressure wave within the casing pipe 60 which in turn impinges upon the rupture disc or membrane 68 in the end of piston 12 to fire the detonating mixtures 72, 74 within the detonator cup.
- This detonation in shell 64 passes energy through the opening 48 within the carrier 46 to initiate the shaped charge 58 within the cylinder 12. This in turn causes the shaped charge 58 to penetrate into the formation F and to develop a communication path between the interior of the casing string and the formation.
- penetrating is used to describe the process for opening a communication path into the formation.
- the reason that penetrating the formation is desirable is that the permeability of porous reservoir rock is usually reduced or plugged near the wellbore due to the leakage of drilling fluids into the first few inches of rocks surrounding the wellbore. This reduces permeability near the wellbore and is referred to as skin damage.
- the shaped charges are not designed to punch a hole in the casing as in a normal perforating system, but rather to establish communication with the reservoir rock and to penetrate the rock itself with a fracturing and penetrating blast that extends communication beyond the skin damage.
- the detonating cord could be pumped in behind a pumpable plug or the like to position the detonating cord into a horizontal reach of pipe. In a vertical or nearly vertical pipe section, gravity would be sufficient to lower a detonating cord weighted on its lower end, into a pipe string.
- other methods could be used to develop a pressure wave for initiating the shaped charge.
- detonators might be used to initiate the explosion of the shaped charged within the centralizing cylinder 12.
Abstract
Description
Claims
Priority Applications (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9606137A GB2296924B (en) | 1993-10-07 | 1993-10-07 | Method and apparatus for downhole activated wellbore completion |
CA002172047A CA2172047C (en) | 1993-10-07 | 1993-10-07 | Method and apparatus for downhole activated wellbore completion |
AU53274/94A AU5327494A (en) | 1993-10-07 | 1993-10-07 | Method and apparatus for downhole activated wellbore completion |
PCT/US1993/009685 WO1995009966A1 (en) | 1993-10-07 | 1993-10-07 | Method and apparatus for downhole activated wellbore completion |
NO19961374A NO323551B1 (en) | 1993-10-07 | 1996-04-03 | Method for perforating a soil formation which is intersected by a borehole. |
NO20054559A NO327684B1 (en) | 1993-10-07 | 2005-10-04 | System for centralizing a casing in a well |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/US1993/009685 WO1995009966A1 (en) | 1993-10-07 | 1993-10-07 | Method and apparatus for downhole activated wellbore completion |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1995009966A1 true WO1995009966A1 (en) | 1995-04-13 |
Family
ID=22237062
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1993/009685 WO1995009966A1 (en) | 1993-10-07 | 1993-10-07 | Method and apparatus for downhole activated wellbore completion |
Country Status (5)
Country | Link |
---|---|
AU (1) | AU5327494A (en) |
CA (1) | CA2172047C (en) |
GB (1) | GB2296924B (en) |
NO (2) | NO323551B1 (en) |
WO (1) | WO1995009966A1 (en) |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5505260A (en) * | 1994-04-06 | 1996-04-09 | Conoco Inc. | Method and apparatus for wellbore sand control |
WO2003002849A1 (en) * | 2001-06-29 | 2003-01-09 | Shell Internationale Research Maatschappij B.V. | Method and apparatus for detonating an explosive charge |
US7152676B2 (en) | 2002-10-18 | 2006-12-26 | Schlumberger Technology Corporation | Techniques and systems associated with perforation and the installation of downhole tools |
WO2007056121A1 (en) * | 2005-11-04 | 2007-05-18 | Shell Internationale Research Maatschappij B.V. | Monitoring formation properties |
US7284601B2 (en) | 2003-01-09 | 2007-10-23 | Shell Oil Company | Casing conveyed well perforating apparatus and method |
US7493958B2 (en) | 2002-10-18 | 2009-02-24 | Schlumberger Technology Corporation | Technique and apparatus for multiple zone perforating |
US7753121B2 (en) | 2006-04-28 | 2010-07-13 | Schlumberger Technology Corporation | Well completion system having perforating charges integrated with a spirally wrapped screen |
US8151882B2 (en) | 2005-09-01 | 2012-04-10 | Schlumberger Technology Corporation | Technique and apparatus to deploy a perforating gun and sand screen in a well |
CN111919011A (en) * | 2018-02-23 | 2020-11-10 | 狩猎巨人公司 | Autonomous tool |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6637508B2 (en) | 2001-10-22 | 2003-10-28 | Varco I/P, Inc. | Multi-shot tubing perforator |
GB0502395D0 (en) * | 2005-02-05 | 2005-03-16 | Expro North Sea Ltd | Reservoir monitoring system |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3318381A (en) * | 1964-09-30 | 1967-05-09 | Chevron Res | Method and apparatus for injecting fluids into earth formations |
US3468386A (en) * | 1967-09-05 | 1969-09-23 | Harold E Johnson | Formation perforator |
US4541486A (en) * | 1981-04-03 | 1985-09-17 | Baker Oil Tools, Inc. | One trip perforating and gravel pack system |
US4612992A (en) * | 1982-11-04 | 1986-09-23 | Halliburton Company | Single trip completion of spaced formations |
US4616701A (en) * | 1985-06-06 | 1986-10-14 | Baker Oil Tools, Inc. | Well perforating apparatus including an underbalancing valve |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5228518A (en) * | 1991-09-16 | 1993-07-20 | Conoco Inc. | Downhole activated process and apparatus for centralizing pipe in a wellbore |
US5224556A (en) * | 1991-09-16 | 1993-07-06 | Conoco Inc. | Downhole activated process and apparatus for deep perforation of the formation in a wellbore |
-
1993
- 1993-10-07 AU AU53274/94A patent/AU5327494A/en not_active Abandoned
- 1993-10-07 WO PCT/US1993/009685 patent/WO1995009966A1/en active Application Filing
- 1993-10-07 CA CA002172047A patent/CA2172047C/en not_active Expired - Lifetime
- 1993-10-07 GB GB9606137A patent/GB2296924B/en not_active Expired - Lifetime
-
1996
- 1996-04-03 NO NO19961374A patent/NO323551B1/en not_active IP Right Cessation
-
2005
- 2005-10-04 NO NO20054559A patent/NO327684B1/en not_active IP Right Cessation
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3318381A (en) * | 1964-09-30 | 1967-05-09 | Chevron Res | Method and apparatus for injecting fluids into earth formations |
US3468386A (en) * | 1967-09-05 | 1969-09-23 | Harold E Johnson | Formation perforator |
US4541486A (en) * | 1981-04-03 | 1985-09-17 | Baker Oil Tools, Inc. | One trip perforating and gravel pack system |
US4612992A (en) * | 1982-11-04 | 1986-09-23 | Halliburton Company | Single trip completion of spaced formations |
US4616701A (en) * | 1985-06-06 | 1986-10-14 | Baker Oil Tools, Inc. | Well perforating apparatus including an underbalancing valve |
Cited By (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5505260A (en) * | 1994-04-06 | 1996-04-09 | Conoco Inc. | Method and apparatus for wellbore sand control |
WO2003002849A1 (en) * | 2001-06-29 | 2003-01-09 | Shell Internationale Research Maatschappij B.V. | Method and apparatus for detonating an explosive charge |
US7152676B2 (en) | 2002-10-18 | 2006-12-26 | Schlumberger Technology Corporation | Techniques and systems associated with perforation and the installation of downhole tools |
US7493958B2 (en) | 2002-10-18 | 2009-02-24 | Schlumberger Technology Corporation | Technique and apparatus for multiple zone perforating |
US7284601B2 (en) | 2003-01-09 | 2007-10-23 | Shell Oil Company | Casing conveyed well perforating apparatus and method |
US7284489B2 (en) | 2003-01-09 | 2007-10-23 | Shell Oil Company | Casing conveyed well perforating apparatus and method |
US7975592B2 (en) | 2003-01-09 | 2011-07-12 | Shell Oil Company | Perforating apparatus, firing assembly, and method |
US8151882B2 (en) | 2005-09-01 | 2012-04-10 | Schlumberger Technology Corporation | Technique and apparatus to deploy a perforating gun and sand screen in a well |
WO2007056121A1 (en) * | 2005-11-04 | 2007-05-18 | Shell Internationale Research Maatschappij B.V. | Monitoring formation properties |
AU2006311880B2 (en) * | 2005-11-04 | 2010-06-03 | Shell Internationale Research Maatschappij B.V. | Monitoring formation properties |
US7753121B2 (en) | 2006-04-28 | 2010-07-13 | Schlumberger Technology Corporation | Well completion system having perforating charges integrated with a spirally wrapped screen |
CN111919011A (en) * | 2018-02-23 | 2020-11-10 | 狩猎巨人公司 | Autonomous tool |
Also Published As
Publication number | Publication date |
---|---|
NO961374D0 (en) | 1996-04-03 |
NO20054559D0 (en) | 2005-10-04 |
AU5327494A (en) | 1995-05-01 |
NO961374L (en) | 1996-04-03 |
GB9606137D0 (en) | 1996-05-22 |
GB2296924B (en) | 1997-04-23 |
GB2296924A (en) | 1996-07-17 |
NO20054559L (en) | 1996-04-03 |
CA2172047A1 (en) | 1995-04-13 |
NO323551B1 (en) | 2007-06-11 |
CA2172047C (en) | 2001-01-02 |
NO327684B1 (en) | 2009-09-14 |
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