US3155164A - Means for setting tubular bodies - Google Patents

Description

Nov. 3, 1964 R. w. KEENER MEANS FOR SETTING TUBULAR BODIES 2 Sheets-Sheet 1 Filed Jan. 10, 1961 ATTORA-[V Nov. 3, 1964 R. w. KEENER MEANS FOR smmc; TUBULAR BODIES 2 Sheets-Sheet 2 Filed Jan. 10, 1961 INVENTOR. /?(/JJ'// VV. Keener ATTORNEY United States Patent "ice 3,155,164 MEANS FUR SETTELJG TUBULAR BGDlES Russell W. Keener, Houston, Tex, assignor to Set Set Corporation, Houston, Ten, a corporation of Texas Filed Fan. 10, 1961, Ser. No. 81,902 14 Claims. (Cl. 166-63) This device relates to means and method for setting tubular bodies in surrounding supports. Examples of such bodies are bridging plugs, liners, packers, casing patches, hangers, hold-downs, and the like which are set in an oil well.

The use of explosive generated shock waves, as distinguished from gas pressure, in setting such tubular bodies has decided advantages, such as the elimination of drawback following expansion due to resilience of the material, thus insuring a tight fit, and the actual re-shaping of the metal of the expanded body to conform to the surrounding part without substantial bulging of either. Previous suggestions for utilizing explosives for this purpose have proposed resort to the expanding, pressured gases generated by the decomposition of the explosive. However, such gases, inevitably, form the expanded body into a bulging or bulbous shape, which results in ineffective contact with the surrounding structure. Another advantage resulting from the use of shock waves in setting such tubular objects, particularly in oil wells, is that no setting tool is required other than the charged body itself which can be properly positioned in the well by suitable means as a wire line or rope.

Applicant has discovered that where the stand-off space between the explosive and the facing body wall is gas filled, the shock waves travel so rapidly that the well liquids in the annulus surrounding the expanding body cannot be evacuated quickly enough to prevent the surrounding support structure, such as the oil well casing, from being badly bulged or otherwise adversely affected by the force of the shock front transmitted through the liquid which, in the extremely brief interval of shock wave action, functions as a solid. Other problems result from the tendency of the expansible object, such as a bridging plug, to react in a downward direction during the explosion so that the final setting does not occur at the planned zone of the well, and the tendency of the detonation to run along the explosive so that where detonation occurs simultaneously at both sides of an explosiveequipped mandrel, the detonation waves meet at midpoint on the surface of the mandrel and then pass outwardly in greatly amplified jet stream action which may have injurious effect on the restricted adjacent part of the surrounding structure.

Still another problem in explosive setting of tubular objects arises from the use of shaped charges to obtain directional and efficiency advantages. It has proven very diflicult to realize such advantages where the stand-off space is gas filled.

Accordingly, one object of the present invention is to provide means for insuring evacuation of well liquids from the space around the expansibie body, upon detonation of the explosive, to avoid damage to the surrounding structure.

Another object is to provide means for deforming metal, as in setting tubular bodies, while retaining the directional and efiiciency advantages of shaped charges.

Another object is to provide means for setting tubular objects utilizing shock waves, while preventing longitudinal displacement of the body during setting.

Still another object is to prevent the detonation waves traveling oppositely around a mounting mandrel from meeting at a point remote from the initial detonation zone to produce a greatly amplified jet stream effect.

3,155,164 Patented Nov. 3, 1964 These objects and other more detailed objects hereafter appearing are attained by the use of the structures illustrated in the accompanying drawings in which,

FIG. 1 is a view of a bridging plug embodying the invention suspended in a well.

FIG. 2 is a section showing the plug after setting.

FIG. 3 is an enlarged vertical central section through the plug positioned in a well and prior to setting.

FIG. 4 is an elevation showing the explosive-equipped mandrel portion of the device.

PEG. 5 is a horizontal section and top view taken on broken line 5-5 of FIG. 4.

FIG. 6 is a vertical central section illustrating a modification.

Phil. 7 is a detail vertical section illustrating still another modification.

According to the invention herein disclosed, a tubular body, such as a bridging plug, is provided with longitudinally spaced slip segments surrounding its outer surface and a resilient sealing band or ring between the slips. Within the body there is mounted a mandrel upon the outer surfaces of which is applied explosive sheeting, preferably, in V configuration to form, in effect, spaced, at least partially annular, shaped charges. The stand-off space between the explosive and the facing body wall is filled with liquid or other dampening material which has the effect of so retarding the explosive generated shock waves as to reform the body metal without rupturing, while permitting the well liquid between the expanding body and the surrounding structure to evacuate upwardly and thus prevent transmission of damaging shock directly to the surrounding structure. The top of the tubular body is opened to the well fluid and for releasing explosive generated gases. Between the ends of the explosive sheeting, remote from the detonation points, there are provided resilient strips of rubber, which prevent the detonation waves traveling around the explosive mandrel from meeting.

FIGS. 1-5 show a bridging plug, conveniently of aluminum, having a generally tubular body 8 and a closed bottom 9. Received upon the reduced extremity ill of the body at the open upper end thereof is a sub 11 which is arranged for attachment to an adaptor 12 and a wire line anchor device 13. FIG. 1 shows the device suspended within the casing portion 14 of a well at the point where the bridging plug is to be set.

FIGS. 3 and 4 show the explosive support mandrel 15 having longitudinally-spaced, annular V- section recesses 16 and 17. Lower recess 17 is shallower than upper recess 16 by the distance 18, for a purpose to be described. FIG. 3 shows the mandrel seated upon the bottom 9 of the body. Laid upon the outer surface of the mandrel are sheets 19 and 20 of detonant type explosive material, such as P.E.T.N. This material, as supplied commercially by du Pont, is sufficiently pliable and linearly yielding as to be worked by hand into close conformance with the contours of the mandrel. The sheets, preferably, are cut initially to form the shaped charge and connecting tongue portions, to be described. The two cut sections are held snugly against the apices of the annular grooves by wires or cords 21 and 22. Connecting the V-shaped parts are strips 19a and 200. As best shown in FIGS. 4 and 5, the V-shaped flaps of explosive sheeting do not completely surround the mandrel, longitudinal spaces being provided between their adjacent edges in which are placed rubber buffer strips 23 which also follow the contour of the mandrel surface.

At the top of the mandrel there is provided a diametral recess 25 with a central circular enlargement 26 (FIG. 5). The floor of this recess slopes downwardly and outwardly from the center, and on this floor are placed strips 27 and 27a of explosive which may form extension tongues from the side sheets 1% and 20. A stack of explosive discs 28, forming a booster charge, is provided in enlargement 26.

As best shown in FIG. 3, there is provided above the mandrel and resting on discs 28 a wooden block or baille 30 secured in position by nails 31 and having a lined central hole with heavy liner 32 and additional holes 33. Previously mentioned sub 11 and adapter 12 projecting above body 8 are secured to the body by shear screws 34 and have apertures 35 for transmitting fluids to and from the interior of the casing and, thence, through holes 33 to the space between the mandrel and body side wall. The body side wall, near its upper extremity, is annularly recessed as at 36 to provide a weakened zone. A fuse cap 37 extends through central hole 32 in the wooden member and is provided with detonating wiring 38 and 39. The lining 32 is sufficiently heavy and tough to concentrate and direct the explosive effect of cap or fuse 37 against booster charge 28.

Surrounding body 8 are longitudinally spaced, annularly-arranged slip segments 42 and 43. The lower set of segments 42 have their teeth inclined downwardly so as to most effectively resist downward sliding of the body, when set. The upper set of segments 43 have upwardly inclined teeth for most effectively opposing upward movement of the body, when set. The segmental slips are normally secured in position by frangible rings as and 45. Between the sets of segmental slips there is provided a rubber sealing ring or band 46, the outer surface of which is formed of V-section with outward apex. Between adjacent segmental slips in each annular group there are provided longitudinal spaces 47 and 48.

In FIG. 2, which shows the plug set, the bottom end of the plug side wall has been sharply outset at what may be called the fulcrum point 49. Slips 42 and 43 bite into the suprrounding casing wall and the plug side wall substantially parallels the casing, being free of the excessive bulging shape which is characteristic of gas pressure exploded bodies. The top of the body is severed at weakened zone 36 to release the supporting cable and its attachment. Alternatively, weakened zone 36 may be omitted and the cable released by a sharp tug on shear screws 34-. The latter case provides a check upon the security of setting of the plug.

The type, amount, positioning, and stand-off spacing of the explosive from the facing body wall is adjusted so that the shock waves generated upon detonation are of adequate strength and proper direction to expand the body wall outwardly, as will be explained, without rupturing the metal.

In a specific embodiment of a bridging plug for 4 /2 in. 9-11 pound casing, the following dimensioning has been found exemplary:

Casing-inner diameter in 4 Plug body-outer diameter (overall) in 3,625 Annulus(A)-radial in .375 Plug body-inner diameter in 2.625 Plug body material-aluminum.

Plug bodymaximum wall thickness in .500 Explosive sheeting-thickness in A; Explosive sheetingtotal weight grams 28 Stand-olf-lower V-groove (B) in Stand-off-upper V-groove (C) in Mandrel material-cast iron.

Mandrel-maximum diameter in 2,593 Mandrelmid-point diameter in 2,093

FIG. 6 shows a modification adapted for use within small gauge casing, say 278 inch diameter. Mounted Within the tubular body 59 is a rod type mandrel 51, preferably of metal, having a wrapping of explosive sheeting 52 facing the portion of the body wall which is to be affected. The rod has a broad base 53 which snugly fits against the bottom of body 50 for centralizing the explosive equipped rod-type mandrel.

The explosive sheeting is wrapped over the top of rods 51, as at 54. Mounted on top of the rod and explosive wrapping is a heavy metal cap 55 having a central vertical orifice 56 for receiving the ignition cap 57 having wiring 58. Cap 55 serves the same purpose as heavy liner 32 in H6. 3, that is, to concentrate the explosive effect of the cap upon the main explosive which, in the form contemplated, is relatively stable.

Additional explosive strips are provided at 59 and 5%, respectively, opposite the fulcruming portion at the bottom of the body wall and rubber sealing O-ring 61. Holes 63 are provided in the thickened upward projection of the body wall to admit well fluid into the interior of the body and provide for escape of gases. Received about the body are lower and upper segmental slips 64 and 65. The body wall between the slips is thickened and its surface inclined as at as for longtiudinally displacing ambient fluid as the body wall is expanded. Adjacent part 66 there are provided holes 67 for aiding in transfer of well liquid across the body wall during expansion.

In FIG. 7, lower groove 68 in mandrel 6% is tilted so that its axis will intersect a lower point on the plug body wall, thus lowering and sharpening the fulcruming oint and also tending to increase the path of the shock wave through the dampening medium.

In use of the form shown in FIGS. 1-5, the mandrel and body are assembled with the sub 11 and cable attaching pieces 12 and 13. Wooden block or batlle 3% is superimposed on the booster charge 28 and secured in position. Blasting cap 37 is then positioned in hole 32 and its wires connected to ground and a hot wire extending along the supporting cable. The lower portion of the body is then filled with a liquid, conveniently water, so as to completely immerse the mandrel and fill the stand-off space between the explosive sheeting and the facing body wall. Other shock wave carrying material having proper dampening effect, may be used. The device is then attached to the cable and run into the well to the proper position at which the bridge plug is to be set.

When hot wire 39 is then energized, the detonation wave travels from booster charge 28 through strip tongues 27 and 27a and explosive sheets 19 and 20. As indicated by the arrows in FIG. 5, detonation travels in both directions around both explosive sheets 19 and 20. However, the detonation waves traveling oppositely around the mandrel cannot meet because of the intervening buffer strip means 23. The shock waves resulting from the detonation travel generally normal to the axis of the mandrel. The shock wave at the surface of the charge travels at the very high velocity on the order of 20,000 feet per second or more and at pressures approximating 2,000,000 p.s.i. However, since the shock wave must travel the stand-off distance through liquid, the velocity of the Wave will be materially reduced upon reaching the body wall to a velocity on the order of 700 feet per second and the pressures reduced to the range of 20,000-40,000 p.s.i. The shock wave, nevertheless, is adequate to exceed the yield strength of the body wall and expand or deform the body metal sharply about the bottom fulcrum point 49 to the position shown in FIG. 2. In the set position, the segmental slips and sealing band, respectively, bite into and snugly engage the surrounding casing wall. Due to the lesser depth of bottom shaped charge region 17, the shock wave originating therefrom reaches the body a brief interval before the shock wave from the upper shaped charge section so as to set lower segmental slips 42 before the upper slips are set and before the explosive can displace the plug body downwardly.

During the outward expansion of the body wall, the well liquids in the annulus between the tubular body and the casing are forced upwardly so as to evacuate this space and avoid the transmission of plug body movement through the liquid to the casing. The V-shaping 'of the sealing band or its mounting aids displacement of the annulus of liquid by applying a longitudinal component thereto during outward wall movement. Also, the severing of the body wall at the weakened region 36 prevents expansion of the body wall thereabove so that the larger annulus remains available as a less restrictive egress path for the displaced well liquid.

Of importance in evacuation of the annulus around the plug body is the fact that the directioning and concentration of shock waves permits the expansible body to be much shorter, yet to set more firmly than would be possible where explosive generated gas pressure is relied upon as the expanding force.

Holes 35 in parts 11 and 12 insure equalization of the initial pressures on both sides of the tubular body wall. The stand-off space could be filled with ambient well liquid through these holes. However, it is preferable that the stand-off space he prefilled with liquid or other dampening substance, both to assure complete filling and to permit a control of the type of liquid to which the explosive is exposed. It is very important that all gas pockets be eliminated from the stand-off space, as applicant has discovered that damage may result where air pockets remain in the path of the outwardly traveling shock waves. The spaces 47 and 43 between the annular sets of segmental slips provide paths for the egress of well fluids.

It has been found that the provision of the damping liquid through which the shock wave travels has the effect of making determination of the quantity of explosive and stand-off distance, as well as the angle of the shaped charge much less critical than where the shock waves must travel through air. Moreover, the included angle of the shaped charge, which determines its efficiency as concentration means, may be sharper than where the stand-01f is gas filled. An angle of approximately 90 has been found satisfactory. Notwithstanding the dampening effect of the liquid upon the shock waves, the setting of the plug under the influence of the shock wave occurs substantially before the effect of the expanding gases is realized. These gases are promptly released through the open top of the body so that they can have no material effect upon the body. In fact, the effective expansive force of explosive generated gases is much less, on the order of one fifth the force available from shock wave action, and cannot be effectively concentrated and guided without heavy channel structures. explosive required by applicant is materially less than would be required in heretofore known methods of explosive induced metal expansion.

The form in FIG. 6 is similar to that in the first form, with the exception of the substitution of explosive sheets and bands for the shaped charges previously used, due to space limitation. In this form, also, the explosive is immersed in liquid which dampens the outward travel of the shock waves sufficiently to permit evacuation of the well liquids upwardly from the annulus about the tubular body. The presentation of the broad faces of the charge strips to the plug side wall, while only narrow edges of the strips face longitudinally, results in utilization of a large proportion of the shock wave effect in deforming the body metal, while a relatively small proportion of the shock wave energy is dissipated. In fact, the downward shock wave appears to be diverted outwardly upon contact with heavy spacing foot 53 at the bottom of the mandrel. The explosive sets the segmental slips 64 and 65 and the sealing strip 61, as in the previous form and severs the body wall at the weakened region 62. Also, as in the previous form, explosive generated gases are released through the open upper end of the tubular body before adversely affecting the body side wall.

The particular type of explosive, its quantity, positioning, stand-off distance, and its shaped charge angle are readily determinable, in relation to the physical characteristics of the tubular body wall to be expanded, by those skilled in the art of explosives. Ample tests have now proven' that the described method and means for Thus the amount of setting bridging plugs and like tubular members by means of shock waves is entirely feasible and results in substantial economy as well as proper setting in practically all cases, without rupturing the affected metal and without excessive bulging or other damaging to the outer casing. Aluminum has been found to be exemplary material for the tubular body since its relative softness permits reduction in the weight of explosive, while being readily milled in case it is desired to remove the body. Neither the dampening liquid surrounding the explosive, nor the head of liquid thereabove, nor the openings which dissipate the expanding gases generated by the explosion adversely affects the highly directional character and metal reforming action of the shock waves produced by the explosion. This insures uniform lateral shifting and re-shaping of the side wall of the ceiling body and uniform bearing of the gripping and sealing elements thereof against the opposing wall. The term detonant-type explosive, as used herein, refers to well known explosives,

such as the PELTN. mentioned above, capable upon detonation of producing highly directional shock waves traveling very much faster than expanding gases in all directions which may also result from the explosion.

The invention may be modified in various respects as will occur to those skilled in the art, and the exclusive use of all modifications as come within the scope of the appended claims is contemplated.

I claim:

1. In combination, a tubular body for setting in a well wall, a mandrel positioned within said body, a detonatetype explosive applied to the surface of said mandrel, means for charging the interior of said body between the body wall and said explosive with shock wave dampening substance, means to position said body within a well bore, means to detonate said explosive, the type, quantity, positioning, and standoff distance of said explosive being adjusted relative to the facing body wall so that the explosive generated shock wave traveling through said substance in said body will expand said body wall without puncturing, and means for releasing from said body substantially all pressured gases generated by the explosive before they can substantially affect the body wall.

2. The combination described in claim 1 further in cluding annular sealing structure surrounding said body, said structure having a sealing part and at least one wall facing both radially outwardly and longitudinally for propelling fluid between the body and well walls longitudinally during outward movement of said body wall.

3. The combination described in claim 1 further including a \/-section band surrounding said body with its apex outward for propelling fluids in the space between the body and well walls longitudinally out of said space during expansion of the body wall.

4. The combination described in claim 2 in which said band is of resilient material and serves as sealing means when lodged between the body and well walls.

5. The combination described in claim 1 further including segments disposed annularly about said body, said segments having gripping structure on their outer faces and there being substantial spaces between adjacent segments for egress of well fluid from between the body and well walls during expansion of the body wall.

6. The combination described in claim 5 further including a resilient sealing band surrounding said body adjacent said segments, said band having at least one wall facing radially outwardly and longitudinally for propelling fluids from between the body and well walls during expansion of said body wall.

7. In combination, a tubular body for setting in a well, a mandrel in said body, strip detonant-type explosive material applied to the surface of said mandrel and facing the body side wall, means for charging the interior of said body with shock wave dampening substance, means projecting above said body for positiona ing the same in a well, there being an annularly weakened zone between said body wall and said projecting means, and means to detonate said explosive, the type, quantity, and stand-off distance of said explosive being adjusted for producing shock Waves capable of expanding the body side wall Without rupturing, while severing said body at said weakened Zone to release said projecting structure, the top of said body being open for releasing pressured gases generated by said explosive before said gases can substantially alfect said body.

8. In combination, a tubular body for setting in a well, a mandrel positioned within said body, axially spaced, detonant-type explosives applied to the surface of said mandrel and facing the body side wall, means to charge the interior of said body with shock wave dampening substance, and means to detonate said explosives to produce shock waves traveling radially of said mandrel for expanding said body wall, one of said explosives being appreciably closer to its facing body wall part than the other so as to cause setting of said wall part before other parts of said wall are set and before said body can be impelled longitudinally by explosive action.

9. The combination described in claim 8 further including longitudinally spaced slip structures on the body wall parts abreast said explosives, said structures when set resisting slippage of said body in opposite directions.

10. The combination described in claim 9 in which the lower of said explosives is elfectively closer to its facing body wall part than the other explosive and the lower slip structure has teeth inclined to resist downward movement of said body when set.

11. A metal displacing device comprising a support body, detonant-type explosive means applied to the surface of said body and facing the Work, means for igniting said explosive means intermediately thereof, said explosive means extending oppositely from said ignition means partially around said support and having ends remote from said ignition means providing a space therebetween, and resilient bulfer means interposed in said space forpreventing colliding of detonation Waves traveling oppositely along said explosive means.

12. In combination, a tubular body to be set in a support, a mandrel within said body, an explosive applied to the outer surface of said mandrel and facing the body side wall, means for charging the interior of said body with shock Wave dampening substance, means for igniting said explosive intermediately, said explosive extending from said ignition means partially around said mandrel in opposite directions, and resilient buffer structure interposed between the ends of said explosive re mote from said ignition means, the type, quantity, and stand-off distance of said explosive from said body wall being adjusted so as, upon detonation, to expand said body wall without rupturing, said body being open at the top for promptly releasing pressured gases generated, and said bulfer structure intercepting shock waves traveling along said explosive around said mandrel to prevent said latter shock waves from meeting in a manner to produce an accentuated effect upon the restricted adjacent part of the body wall.

13. The combination described in claim 12 in which said explosive is in the form of sheet material laid upon said mandrel and presents a V in axial section to the facing body wall for producing a shaped charge eifect capable of reforming the body Wall for setting in the support.

14. In combination, a tubular body to be set in a support, a mandrel within said body, an annular, V- section groove in the surface of said mandrel with its axis at an acute angle to the axis of said body, detonant type explosive applied to said groove for producing a shaped charge effect, means to charge said body with liquid before detonation thereof and means to detonate said explosive to cause a shock wave to travel through said liquid to the body wall for expanding the same, the type, weight, and stand-off of said explosive being adjusted to expansively deform said wall without rupture and said body wall being sharply offset at the intersection of said groove axis therewith.

References Cited by the Examiner UNITED STATES PATENTS 2,076,307 4/37 Wells et a1. 166-63 2,214,226 9/40 English 16663 X 2,519,116 8/50 Crake 166-63 2,656,891 10/53 Toelke 16663 2,745,345 5/56 Sweetman l0221.8

CHARLES E. OCONNEL, Primary Examiner.

Claims (1)

1. IN COMBINATION, A TUBULAR BODY FOR SETTING IN A WELL WALL, A MANDREL POSITIONED WITHIN SAID BODY, A DETONATETYPE EXPLOSIVE APPLIED TO THE SURFACE OF SAID MANDREL, MEANS FOR CHARGING THE INTERIOR OF SAID BODY BETWEEN THE BODY WALL AND SAID EXPLOSIVE WITH SHOCK WAVE DAMPENING SUBSTANCE, MEANS TO POSITION SAID BODY WITHIN A WELL BORE, MEANS TO DETONATE SAID EXPLOSIVE, THE TYPE, QUANTITY, POSITIONING, AND STANDOFF DISTANCE OF SAID EXPLOSIVE BEING ADJUSTED RELATIVE TO THE FACING BODY WALL SO THAT THE EXPLOSIVE GENERATED SHOCK WAVE TRAVELING THROUGH SAID SUBSTANCE IN SAID BODY WILL EXPAND SAID BODY WALL WITHOUT PUNCTURING, AND MEANS FOR RELEASING FROM SAID BODY SUBSTANTIALLY ALL PRESSURED GASES GENERATED BY THE EXPLOSIVE BEFORE THEY CAN SUBSTANTIALLY AFFECT THE BODY WALL.

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