CA2164576A1 - Device for plugging horizontal or vertical wells in oil or similar drillings - Google Patents

Abstract

A device is provided for plugging horizontal or vertical wells in oil or similar drillings, which can be introduced to predetermined depths to become a part of the piping, operated by hydraulic inflation, and which is a non-recoverable type. The device includes an elastic packing element, which is radially expandable by inflation.
A hollow tip is provided at its upper end, which is connected to a secondary valve assembly. A primary body includes a primary valve assembly and an elastic cup.
Rigid joint element disengageable connecting means temporarily connect the primary body and the packing element together. Means are also provided which are operable by the elastic cup, to release the disengageable connecting means to separate the primary body from the elastic packing element. A flexible tube interconnects the primary valve assembly and the secondary valve assembly, in order to provide a conduit for fluid to the interior of the elastic packing element. A carrying casing is provided, which serves to transport and operate at least one plastic packing element.

Description

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This invention is dir~led to a device for plugging horizontal or vertical wells in oil or similar ~1rillings, where drilling is necçq~ry. More specifically, this invention relates to a device which is adapted to be placed at a predetermined depth within the well, to be operated by simple hydraulic inflation, which then becomes a 5 plug that assures effiçiçnt safe sealing, by avoiding hydraulic comm--ni~-~tion between strata traversed by drilling, whether it be horizontal or vertical.
The fluid column filling the well is very illlpol~lt throughout the drilling process and during the completion of the well, after pipe setting and during its productive life, and even after its productive life is over.
The absence of fluids and/or a dçfi~ ient column may cause problems of such m~gni~lde that they can inl~;lrer~ with the productive life, and even lead to the total loss of the well. This increases the risks and hazards implied by uncontrolled blows.
Attending to these problems and fixing these shollcol-~lgs involves extremely difficult and h~7~rdous work.
There are various chemical and mç~h~nic~l methods used to plug wells, be they open or piped. In one method, a chemical solution is applied by injecting into the well fluids that can solidify, generally by setting (e.g.,cement) or by catalyzing (e.g., polymers). These elements, after setting, withstand pl~;s~ure in leaking areas and, after becoming solid, permit a new drilling, so that work may continue. In 20 order to place such setting liquids both in open and in piped wells, it is necessary for the fluid column to have s~fficiçnt support so as to ~ ir~ in and offset the pressure produced by the liquid plug balanced in the column, which is heavier than the entire fluid making up the column.

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In the event of entry in the lower layers, a packing element must be emplaced to interrupt hydraulic commlmic~tion~ and therefore to prevent entry to the fractured stratum which has no hydraulic support.
Currently available elements resort to mechanical p~cking, and work by 5 tension or weight. Such elemPnt~ are limited by their low p~cking ability and uncontrolled movement, relative to the distance needed to produce their effect. This method is almost totally discarded in relation to drifted or horizontal wells.
Consequently, the inflatable p~cking~ available today are limited by their low support margin and the impossibility of placing more than one seal per trip or stroke 10 down the well, due to o~l~ling difficulties, as well as extremely high cost.
It is noteworthy that in le",~l~y or permanent abandonment of areas or wells no longer of economic interest, the methods used must comply with current ecological standards, with high unrecoverable investment costs.
Cullt;n~y, the only method and elements available for the fixing and closing 15 of wells require work or investment programs almost as costly as those required for starting up production in a high yield well.
Accordingly, by a broad aspect of the present invention, a device is provided for plugging horizontal or vertical wells in oil or similar ~rilling~. Such device can be introduced to a predetermined depth in the well, becoming a part of the piping, to 20 be of a non-recoverable type and which is operated by hydraulic inflation. The device comprises: an elastic packing elem~nt7 the elastic pac,king element being radially expandable by inflation, the packing çlçmPnt including a hollow tip at its upper end, the hollow tip being connect~d to a secondary valve assembly; a primary body, the primary body including a primary valve assembly and an elastic cup; rigid -216457~

joint elem~o-nt ~ çng~eable connecting means le~ o,dlily connecting the primary body and the p~cking elempnt together, in combination with means, operable by the elastic cup, to release the tli~çng~geable connecting means to separate the primary body from the elastic p~c1~ing çlem~nt; a flexible tube inter~onnecting the primary 5 valve assembly and the secondary valve assembly thereby providing a conduit for fluid to the interior of the elastic packing element; and a carrying casing serving to transport and operate at least one elastic packing element.
By one variant thereof, the primary body comprises a hollow cylindrical stopper provided at its lower end with a seat to seat the primary valve, the hollow 10 cylindrical stopper concentric~lly accommodating the elastic cup.
By another variant thereof, the rigid joint element comprises stems, upstanding from the packing element, each being surrounded by spring members, the stems being adapted to be releasably gripped by latches which are slidable on inclined planes in the body of the primary valve.
By another variant thereof, the elastic p~(cl~ing has l~inforcelllents which limit axial stretching, and preferably, additionally including upper and lower caps and extensible bands, all the reinforcem~.nt.~, the upper and lower caps and the extensible bands being joined by vnlc~ni7~tion; and alternatively also where the hollow tip comprises an inflation tip which is part of the upper reinforcement of the elastic 20 packing element, e.g., where the secondary valve is conn~cted to the inflation tip; and also preferably where the reinforcçm-~nt.~ of the elastic p~cking element are consistent in shape with the final shape of the elastic p~l,in~ element.
By yet another variant thereof, the secondary valve assembly which is connected to the elastic p~king element includes a secondary check valve.

2164~75 By still another variant thereof, the device includes axial inflation spillways disposed inside the expansible elastic wall of said elastic p~r.king element, e.g., where the elastic p~eking elemPnt has reinforcements which limit axial ~ chillg, and wherein the ~info~ ",~nts are joined to the axial spillways.
S By a still further variant thereof, the flexible tube is provided in fluid communication be~ween the primary valve assembly and the secondary valve assembly.
By a further variant thereof, the ~ png~geable connecting means are bolts.
By a further variant thereof, the main body of the primary valve is disposed so as to be discharged from the primary body, thereby to release the system and to allow the elastic packing element to be infl~ted.
By yet a further variant thereof, the main lock is released from the flexible tube which carries it, by cutting with cut-out cutting bolts, e.g., where the cutting bolts regulate the operation; and/or the cutting tension ~ul?polLillg the cut-out cutting bolts can be predetellllined; and/or the cutting tension supporting the secondary cut-outs is lower than the cutting tension for the main cut-out cutting bolts; and/or where inflation p~es~ule iS regulated by the cutting tension of the main cut-out cutting bolts.
By a further variant thereof, the entire assembly can be drilled.
By yet a further variant thereof, the hollow cylin~lric~l stopper is joined to the flexible tube.
By still a further variant thereof, the elemPnt~ are placed in Op~ldtillg position in the hollow cylin~1ric~1 stopper by the action of a positioning cord; and/or tension for traction-braking suppolling the position cord is lower than the cutting tension of the secondary cut-outs.

By yet a further variant thereof, the elastic cup has a design that can be adapted to the various ~ met~rs of the hollow cylin(lric~l stopper.
By a still further variant thereof, the means for radially exp~n-ling the p~cl~ing element includes a co,l,~ression spring disposed between the valve body and the 5 elastic cup, the means being adapted to release the system and to leave a space for operation; and/or where the co."prcssion spring is m~int~in~ by the secondary cutting lock; and/or where cutting of the secondary lock allows the expansion if the co~cssion spring, which releases the stems forming the rigid connection element.
By another variant thereof, the stems of the rigid connection element contain the flexible tube in folded condition, while the elastic packing ~lement is joined to the primary body; and/or where the main body of the primary valve has displacement holes for the stems; and/or where the secondary cutting locks are linked to the stems.
By still another variant thereof, the flexible tube is attached to the secondary valve by a threaded joint; and/or the flexible tube is attached to the main body by a 15 threaded joint.
By yet another variant thereof, the radial ~l,tlching walls of the elastic packing element are more elastic than the lcinro~;ed ends thereof; and/or where the length of the elastic p~cking elemPnt is variable depending on operating requirements.
By a still further variant thereof, the chamber of the elastic packing element 20 is made watertight with the help of elastic toroidal joints.
The use of the device of aspects of this invention offers considerable advantages over current methodologies. Indeed, it can interrupt hydraulic communication downwards or upwards, in open or piped wells, affording efficacious support to the injected fluid column injected. One or more p~ckin~ elements may be ~16457~

placed at predete.,~ ed depths, depen~ing on op~ ing needs, and thus, they allow working in wells devoid of fluid, i.e., in the absence of hydrostatic column. The use of the device of aspects of this invention allows working in almost all wells which have been declared unproductive for more than ten years and therefore which require 5 permanent abandonment in keeping with current ecological and environmental standards, and at low cost.
These advantages are the direct consequence of the special combination of means making up the device of aspects of the present invention, which basically consists of packing plugs proper, and a special stopper used to descend and work with 10 one or several p~cking plugs, which operate by simple inflation, i.e., fluid compression, with any type of fluid, i.e., cem.~nt, water, test fluid, drilling mud, etc.
Each plug is made up of an elastic p~( ~in~ element that can expand laterally and which, when injected with hydraulic fluid, is deformed conc~ntri~lly. Longitu-dinal ~lr~tcllillg is limited by longit~-~in~l reinforcements which have been placed 15 inside the elastic packing element. In addition, each plug is provided with non-met~llic reinforcements at its ends, the ~einfo~elllents being vulc~ni7ed and placed so as to make up front and rear reinforced shoulders, thereby allowing only transverse ~LIelcllillg for total obstruction of the drilling.
The metallic tip of the plug is placed at its upper end, and is threaded onto a 20 secondary valve, which complem~nt~ the main valve, after the plug is infl~ted and packed.
The special design and combination of the parts allow simple, safe operation, provided the butt end is placed in the seat of the stopper, which will be ~tt~c~e~ to the casing. After the plug is placed in the seat of the stopper, by pressure, the elastic ~164S7~

cup is displaced towards its main valve, cutting the locks of the ejection stems. The springs of the stems are decolllpre~sed, ejecting the packing element and opening the main valve, thereby letting colll~l~ssed fluid enter into the inflatable chamber of the elastic p~l kin~ elem~nt S When the plug is placed outside the conductor casing, the assembly is ready for final inflation, letting the colllpressed fluid pass through the main valve and through a flexible tube to the expandable chamber, infl~tin~ and ~lletclling the lateral contour, and so pacl~ing the assembly against the wall of the well. Inflation pressure is regulated by the main locks which, when cut, allow the retraction of the seatlatches and, consequently, the displ~em~-nt of the sub-assembly of the valve outside the element, i.e., cylindric~l hollow stopper, that carries it.
When more than one element must be used, the cylindrical hollow stopper is loaded. The first element is lowered outside the plug-carrying cylindrical hollow stopper and joined to the rem~ining plugs placed in the plug-carrying cylindrical hollow stopper by means of a turnbuclde. When pressure is increased from the surface, it acts on the elastic cup with a piston-like effect, displacing the assembly until it presses the latches against the seat of the stopper and produces the action described above. With the plug kept in place by packing, the required fluids areinjected. When the pipes, and therefore the cylindrical hollow stopper are raised, the turnbuckles, joined to the plug or to the element previously p~k~d, pulls out the following plug found in the plug-carrying cylindrical hollow stopper, and places it in the seat of the cylindrical hollow stopper, thus allowing its placement according to the mech~ni~m described above, which will be repeated as many times as there areelemtqnt~ to install.

2~5~576 With the aforenn~ntioned cylin-lric~l hollow stopper, more than one plug may be placed, i.e., as many as the cylin~ri~l hollow stopper can contain, introducing the setting fluid between the plugs in a single stroke, and from bottom to top. The lengths and diameters to pack can be adapted to a wide range of operating needs, both S for open, i.e., non-piped, wells and inside the tubing of piped wells, which makes it quite versatile and adapted to find a wide field of application.
By varying the diameters and ~ i.ining the ope~ g valve system, the device of aspects of this invention can be used as a packer for tubes with various diameters, as required for the operation at hand.
By adding a rotary pump above the system, the elements can be infl~ted without the need to circulate inflation fluid in the casing.
The elastomer can be reinforced with iron straps, to allow higher working pressures, and abrasive elements can be added to increase the support capability of the plug as colllpa~ed to the well or casing.
These ~ltPrn~tives make possible low opel~ing costs for the tasks related to the abandonment of old wells, due to the possibility of anchoring the cement inside the abandoned wells, although they have no fluid inside. In this manner, there is no need to install the large equipment n~cec~ry for the in~t~ tion of conventional mecll~nic~l or hydraulic plugs required for this task to provide in permanent abandonment, placing cement at large intervals, i.e., well l,elrol~lion, in order perm~ntontly to plug this artificial communication between permeable layers. This prevents and co~ the undesirable environm~-nt~l impact that unproductive wells may cause when not collc~ ly abandoned.

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In the acco~ ying drawings, Figure 1 is a lon~itu-lin~l cross-section showing a whole plugging device, i.e.,a plug stopper, of one embodiment of this invention, ~esc~n~iing to its ope~ g position;
Figure 2 is a longihl-1in~l cross-section, partially in isometric form, of an enlarged detail of the main valve in its operating position, with all its elements in cooperation;
Figure 3 shows, also in longitu-lin~l, partial and schem~tic cross-section, the inflatable element displaced from the main assembly;
Figure 4 is a longitll~in~l cross-section, partially in isometric form, of the same elements illustrated in the previous figures, with an inflatable element expanded towards the walls of the well;
Figure 5 is a cross-section of the main assembly, showing the main valve, separated from the stopper and joined to the next element by a turnbuclde;
Figure 6 shows an assembly of a second embodiment of this invention, positioned, after fluid is injected and the tubes ascend with the stopper in the new operating position; and Figure 7 is a longihl-iin~l cross-section showing the well after the whole operation is completed, in an embodiment using three lolem~ntc-In all the figures, the same reference numbers and leKers correspond to the same or equivalent parts or elements of the whole, according to the example selected for this explanation of the embodiment of the present plugging device.
As can be seen in Figure 1, the device of an aspect of this invention, i.e., plug-and-stopper, moves inside a well 1, where the packing element A is located 2 1 ~ ~ ~ 7 ~
inside the hollow cylindrical stopper 2 which occupies the space in the col"p,es~ion chamber 3 of the cylindrical hollow stopper 2. The end of the carrying casing 4, as well as the end of the second packing çlempnt B is disposed above chamber 3.
The p~king elements descend, in their "at rest" position.
The cylindrical hollow stopper 2 is attached at its upper end by threaded joints5 to the casing 6, to forrn a continuous assembly from the surface. (See Figure 7).
The cylindrical hollow stopper 2 is provided with an operating seat 7 located above its end or nozzle 8.
An annular circulation space 9 is provided between the body of the cylindrical hollow stopper 2 and the carrying casing 4, which allows the passage of the fluid and/or pressure towards the p~cking assembly which is located in the co"-plession chamber 3.
Figure 1 and details thereof in Figure 2 show the co.-.ponents making up each p~cking P1ement A, B, C, as the case may be. In the detail view in Figure 2, thecomplex frusto-conical elastic cup 10 is displaced downwardly under pressure until the sliding latches 17 are placed in the seat 7 of the hollow cylindrical stopper 2. The stem assembly 15 and the valve body 16 bar the passage to the p,~s~u,~ induced from the surface. A secondary fusible plastic m~tPri~l 22 prevents the displacement of the stems 20 and the subsequent expansion of each associated spring 21.
As now can be seen in Figure 3, by the action of the induced pressure, the sliding latches 17, which are supported by the main cut-outs 19 on the main body 16 make it possible for the complex frusto-conical elastic cup 10 to move from the main body 16 of the valve, sliding the stems 20 and cutting the secondary cut-outs 18 (See Figure 5). The ~i~çn~~ging of stems 20 from the main body 16 thereby frees the 2 ~ G

tension of the springs 21 and separates the packing assembly stems 20 and associated springs 21 from the main body 16 of the valve from the open end or nozzle 8 of the cylin-1ric~1 hollow stopper 2, as pe~ ed by the length of the flexible tube 24.
As seen in the same Figure, the p~(~king elemen~ which is also seen in the S cross-section, inr.ludes lon~itu-lin~lly-extending reinforcemPnt~ 29 to avoid ~ tclling of the elastic p~eking element 28. Lower 30 and upper 26 reinforcement cups are integrated to the elastic p~king element 28 by vulr~ni7~tion. The metallic upperhollow tip 27 which is added to the upper reinforcement cup 26 allows hydraulic communication with the inflatable chamber of the elastic packing element 28. Themetallic hollow upper tip 27 contains a secondary valve 25 which is connected to the flexible tube 24 by means of a nut union 23.
As seen in the same Figure 3, the turnbuckle 12 connects the packing element A with the packing element B, through the engagement 13 of the turnbuckle 12 of the packing element A with the lower engagement 31 of the packing element B by meansof ~ ng~geable bolt means 14. The turnbuckle 12 is located in a bobbin 11 insidethe complex frusto-conical elastic cup 10. The lower engagement ring 31 is vulcan-ized to the lower cup 30 and is used as the joining element for the fixing of the turnbuckle 12.
Figure 4 shows the structure of the assembly with the packing elernent fully plugging the interior of the well 1. The complex frusto-conical elastic cup 10, which is displaced towards the main body 16 of the valve allows the a~mi~.~ion of the fluid into the inflation chamber of the elastic pac.kin~ elemP.nt 28 which expands and fully plugs the space of the well 1.

216~5~û

The colllpl~ssed fluid, in its pushing action exerted on the complex frusto-conical elastic cup 10 produces the breakage, by cutting, of the main cut-outs 19, and the sliding of the latches on the inclined plane of the body 16, thereby allowing the free passage of the entire assembly (as can be seen in Figure 5). The turnbuckle12 still connects with the assembly B which is still located in the carrying casing 4.
The longi~1~in~l cross-section in Figure 6, shows part of the assembly A
already packed. The turnbuckle 12 is released from the assembly B. The cylindrical hollow stopper 2 is already totally sepaldted from the packed assembly A. The assembly B will be placed into its operating position, provided fluid is injected from the surface, at a controlled pressure.
Finally, Figure 7 shows a total longitll~in~l cross-section of a well with its entry zone 32 plugged by the element A, after injection of a setting column 33 on top of the latter. The secondary inlet zone of the perforation 34 is plugged by the packing element B and another setting column 35. The same occurs in the perforation zone 36 with the p~cking elem.qnt C and the stopper 2 in position for injecting a third setting column 37 (not yet p~lrolllled) which is injected through the casing 6, coupled to the stopper 2 by the threaded joint 5.

Claims (37)

1. Device for plugging horizontal or vertical wells in oil or similar drillings, said device being of the type which can be introduced to predetermined depths, and is of a non-recoverable type which is operated by hydraulic inflation to become a part of the piping, said device comprising: an elastic packing element, said elastic packing element being radially expandable by inflation, said packing element including a hollow tip at its upper end, said hollow tip being connected to a secondary valve assembly; a primary body, said primary body including a primary valve assembly and an elastic cup; rigid joint element disengageable connecting means temporarily connecting said primary body and said packing element together, in combination with means, operable by said elastic cup, to release said disengageable connecting means to separate said primary body from said elastic packing element;
a flexible tube interconnecting said primary valve assembly, and said secondary valve assembly thereby providing a conduit for fluid to the interior of said elastic packing element; and a carrying casing serving to transport and operate at least one elastic packing element.

2. The device of claim 1 wherein said primary body comprises a hollow cylindrical stopper provided at its lower end with a seat to seat said primary valve, said hollow cylindrical stopper concentrically accommodating said elastic cup.

3. The device of claim 1 wherein said rigid joint element disengageable connecting means comprises stems, upstanding from said plastic packing element, each said stem being surrounded by a spring member, said stems being adapted to be releasably gripped by latches which are slidable on inclined planes in the body of the primary valve.

4. The device of claim 1 wherein said elastic packing has reinforcements which limit axial stretching.

5. The device of claim 4 wherein said reinforcements additionally include upper and lower caps and extensible bands, all said reinforcements, said upper and said lower caps and said extensible bands being joined by vulcanization.

6. The device of claim 4 wherein said hollow tip comprises an inflation tip which is part of said upper reinforcement of said elastic packing element.

7. The device of claim 9 wherein said secondary valve is connected to said inflation tip.

8. The device of claim 4 wherein said reinforcements of said elastic packing element are consistent in shape with the final shape of said elastic packing element.

9. The device of claim 1 wherein said secondary valve assembly connected to said elastic packing element includes a secondary check valve.

10. The device of claim 1 including axial inflation spillways disposed inside the expansible elastic wall of said elastic packing element.

11. The device of claim 10 wherein said elastic packing has reinforcements which limit axial stretching, said reinforcements being joined to said axial spillways.

12. The device of claim 1 wherein said flexible tube is provided in fluid communication between said primary valve assembly and said secondary valve assembly.

13. The device of claim 1 wherein said engageable connecting means are bolts.

14. The device of claim 1 wherein said main body of said primary valve is disposed so as to be discharged from said primary body, thereby to release said system and to allow said elastic packing element to be inflated.

15. The device of claim 1 wherein said main lock is released from said flexible tube which carries it, by cutting with cut-out cutting bolts.

16. The device of claim 15 wherein said cut-out cutting bolts regulate the operation.

17. The device of claim 15 wherein said cutting tension supporting said cut-out cutting bolts can be predetermined.

18. The device of claim 15 wherein said cutting tension supporting the secondary cut-out bolts are lower than the tension for the main cut-outs bolts.

19. The device of claim 1 wherein inflation pressure is regulated by the cutting tension of the main cut-out bolts.

20. The device of claim 1 wherein said entire assembly can be drilled.

21. The device of claim 1 wherein said hollow cylindrical stopper is joined to said flexible tube.

22. The device of claim 1 wherein said elements are placed in operating position in said hollow cylindrical stopper by the action of a positioning cord.

23. The device of claim 22 wherein tension for traction braking supporting said positioning cord is lower than the cutting tension of secondary cut-out bolts.

24. The device of claim 1 wherein said elastic cup has a design that can be adapted to the various diameters of the stopper.

25. The device of claim 1 where said means for radially expanding said packing element includes a compression spring which is disposed between said valve body and said elastic cup, said compression spring being adapted to release the system and to leave a space for operation.

26. The device of claim 25 wherein a secondary cutting lock maintains said compression spring.

27. The device of claim 26 wherein cutting of said secondary cutting lock allows the expansion of said compression spring, which releases the means forming the rigid connection element.

28. The device of claim 1 wherein stems of said rigid connection element contain said flexible tube in folded condition while said elastic packing element is joined to said primary body.

29. The device of claim 28 wherein said flexible tube stretches when said rigid connection element is released to separate said elastic packing element from said primary body.

30. The device of claim 1 wherein said flexible tube is attached to said secondary valve by a threaded joint.

31. The device of claim 1 or claim 30 wherein said flexible tube is attached to said main body by a threaded joint.

32. The device of claim 1 wherein said radial stretching walls of said elastic packing element are more elastic than the reinforced ends thereof.

33. The device of claim 3 wherein said main body of said primary valve has displacement holes for said stems.

34. The device of claim 33 wherein said secondary cutting locks are linked to said stems.

35. The device of claim 34 wherein said main body of said primary valve supports said main lock bolts and said secondary lock bolts.

36. The device of claim 1 wherein the length of said elastic packing element is variable depending on operating requirements.

37. The device of claim 1 wherein said chamber of said elastic packing element is made watertight with the help of elastic toroidal joints.