US 3529836 A
Abstract available in
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Description (OCR text may contain errors)
Sept. 22, 1970 w. E. HYDE 3,529,835
on. WELL PACKING Original Filed March a. 1965 2 Shets-Sheet 1 FIGI.
' INVENTOR WALTER El HYDE 0 W M a- BY ATTORNEYS Sept. 22, 1970 W. E. HYDE OIL WELL PACKING 2 Sheets-Sheet 2 Original Filed March 2 1965 INVENTOR WALTER E. HYDE BY Amt 1 ATTORNEYS United States Patent U.S. Cl. 277-95 3 Claims ABSTRACT OF THE DISCLOSURE A method, system and apparatus for positioning and setting a squeeze-type well packer in a well bore wherein high temperatures, high pressures and caustic fluids exist to circumvent premature setting of the packer. A packer comprising a plurality of rings or a helix is mounted on a mandrel and portions of the rings or helix are longitudinally interconnected by selectably vitiable, movement retaining means such as a sleeve or wires to circumvent relative movement and premature setting as by encountering obstructions such as casing joints when the packer is moved in a well bore to a desired setting location.
CROSS REFERENCE TO RELATED APPLICATION This application is a continuation of applicants copending application, Ser. No. 436,457 filed Mar. 2, 1965 entitled Well Packers, now abandoned.
FIELD OF INVENTION This invention relates to oil Wells and, more particularly, to methods and apparatus for packing oil wells wherein high temperatures, high pressure, and caustic fluids prevail.
Heretofore, squeeze-type well casing packers have been available for forming a seal in a well casing. Such packers are constructed so that axial compression thereof causes radial expansion thereby sealing the periphery of the packer against the well casing periphery. Usually such packers are formed of an elastically deformable, organic material. Although such packers are sometimes adequate in low temperature and low pressure environments, certain operational problems may be encountered in high temperature and high pressure environments. For example, when well temperatures exceed 350 or 400 F., the organic material of the packer, when acted upon 'by Well fluids, may change form, carbonize and become brittle, and may even burn, thereby adversely affecting the fluid seal provided by the packer. Various forms of inorganic materials have been heretofore utilized in well packers but sometimes these packers tend to prematurely radially expand into contact with the walls of the casing upon encountering a minor obstruction or upon being acted upon by high pressure Well fluids. Such premature setting of the packer at an inappropriate casing depth may occur when forces as low as 1,000 pounds act on the packer, this force being appreciably below the usual design packer setting force of from 5,000 to 20,000 pounds.
In recognition of the need for an improved squeezetype well casing packer of the type heretofore described, it is an object of the present invention to provide such a packer which substantially obviates or minimizes problems such as heretofore noted.
It is a particular object of this invention to provide a squeeze-type well casing packer adapted to maintain an efiicient seal in a high Well temperature and pressure environment.
Another object of this invention is to provide such a squeeze-type well casing packer that is not prone to premature setting or radial expansion prior to the positioning of the packer at the desired level in the well casing and the selective setting thereof.
It is a further object of this invention to provide such a squeeze-type well casing packer which includes restraining means, to circumvent premature setting of the packer, of such an arrangement and construction so as not to interfere with causation of an efficient seal about the full periphery of the well casing.
It is an additional object of this invention to provide such a squeeze-type well casing packer that is uncomplicated and inexpensive and yet is reliable, rugged and long lasting.
SUMMARY OF INVENTION In achieving these and other objects that will become apparent hereinafter, the present invention provides a squeeze-type well casing packer adapted to be axially compressed and radially expanded, the packer comprising a mandrel, a cylindrical layer of packing material about said mandrel, said layer formed of a plurality of abutting coils of inorganic packing material, and restraining means extending from one axial end of the cylindrical layer of packing material to the other axial end thereof for retaining said coils in a radially contracted position prior to radially expanding the same when the packer is positioned at the desired depth in a well.
Additionally, the present invention provides a well casing packer material for coiling about a mandrel, the cross section of the packing being a right-angled parallelogram and which comprises an outer layer of inorganic, rough, heat resistant fabric surrounding an inner core of inorganic deformable plastic material. Such packing material has been found to resist disintegration at high well temperatures and the particular construction thereof guards against packing slippage and aids in securing a uniform seal about the full periphery of the casing.
BRIEF DESCRIPTION OF THE DRAWINGS In describing the invention reference will be made to a preferred embodiment and several modified forms thereof illustrated by way of example in the accompanying drawings, in which:
FIG. 1 is a vertical, cross sectional view of a well casing packer according to the present invention;
FIG. 2 is a vertical, elevational view of an end collar utilized in the well casing packer shown in FIG. 1;
FIG. 3 is a cross sectional view of the packing material utilized in the well casing packer shown in FIG. 1;
FIG. 4 is a vertical, cross sectional view of a modified form of a well casing packer according to the present invention;
FIG. 5 is a side view of a Well casing packer shown in FIG. 4;
FIG. 6 is a vertical, elevational view, partially in cross section, of another modified form of a well casing packer according to the present invention installed upon a construction packer mandrel or jig; and
FIG. 7 is a vertical, cross sectional view of a conventional well casing packer mandrel adapted to receive a packer according to the present invention and to be positioned within a Well casing.
DESCRIPTION OF THE INVENTION Referring in more detail to FIG. 1 of the drawings, a preferred embodiment of a squeeze-type well casing packer according to the present invention includes a cylindrical layer of packing material formed by a helically wrapped coil 1 of packer material, the axial ends of which abut packer end collars 2 and 4.
As shown in FIG. 2, the end collars 2 and 4 comprise a metallic cylindrical portion 6 having a sloping inner face 8 of a helical form. Each collar has a mandrel-receiving, cylindrical bore provided therethrough. The wall thickness of the cylindrical portion 6 is reduced at the circumferential junction of the high point 12 and the low point 14 of the sloped, helically formed face 8, this reduced wall thickness facilitating insertion of one square cut axial end 15 of the helically wrapped packing material under projection 16 formed at the reduced thickness Wall portion of the cylindrical portion 6 as shown in FIG. 4. It should be understood that the collars 2 and 4 are similar in shape but reversely oriented so that the projection 16 on the collar 2 receives the square cut axial end of the helically wrapped material on the left hand end of the packer shown in FIG. 1, while the collar 4 receives the other axial end 15 of the coil 1 of packer material at the right hand end of the packer.
To forestall accidental uncoiling or unwinding of the helically wrapped packer material coil 1 from the position shown in FIG. 1, or to circumvent premature setting of the packer prior to positioning at the desired depth in a well casing, a thin walled cylindrical sheath 20* is provided snugly about the periphery of the cylindrical layer of packer material and the end collars 2 and 4. In the preferred embodiment the sheath 20 is formed of an annealed aluminum tubular shell of suificient wall thickness to forestall premature radial expansion or setting of the packer. When the packer is placed in a well and subjected to increased temperatures and contact with well fluids or with steam or caustics, the aluminum shell 20 is changed into aluminum hydroxide and forms a soft water soluble residue. It therefore does not interfere with achieving an outstanding seal against the casing wall at elevated temperatures and pressures.
As will be apparent, the wall thickness of the aluminum shell may be varied to suit the setting force requirements of the packer. For example, the wall of a sheath of a packer that is designed to be set by exertion of a 5,000 pound force will be appreciably thinner than such a sheath wall on a similar packer designed to be set utilizing forces of about 20,000 pounds. In either case the strength of the shell is sufficient to circumvent accidental premature setting of the packer as might be caused by encountering minor obstructions in the casing or when acted upon by well fluids at advanced pressures.
Referring to FIG. 3, the packing material per se, which is coiled into a cylindrical layer, is preferably square in cross section. Of course the cross section may be of any right-angled parallelogram such as a rectangle that provides the desired radial expansion. The packing material is formed of a square core of inorganic plastic material 22 that is of a relatively nonrigid or deformable construction so as to facilitate axial compression and radial expansion of the packing material. The core 22 is surrounded on all sides thereof by a surface layer 24 of inorganic rough asbestos material the outside periphery of which is also formed in a square. Such packer material is resistant to burning, carbonizing, disintegration or the like when acted upon by well fluids at increased temperatures. Additionally it provides a rugged and long lasting seal at high differential well pressures. Because the rough asbestos surface layer 24 tends to frictionally hold adjacent coils of packer material against slippage therebetween during axial compression and radial expansion, a more uniform seal about the full periphery of the packer is achieved. Similarly, because the packer material is of square cross section, initial axial compression thereof does not tend to misalign a coil of packer material relative to adjacent coils as might be the case as if the material were circular in cross section or the like. During expansion the square plastic core is merely regularly flattened into a rectangle.
As will be appreciated, the radially expandable packer material of the coil '1 provides a particularly outstanding seal when stabilized by the aluminum sheath 20 shown in FIG. 1 which functions to circumvent premature setting of the packer.
A modified form of a squeeze-type well casing packer according to the present invention is shown in FIG. 4. In this embodiment a cylindrical layer of packer material formed by a helically wrapped coil of packer material is bounded on its axial ends by cylindrical end collars 32 and 34 constructed of aluminum or the like. The collars 32 and 34 have radially inwardly projecting circular flanges 36 and 38 respectively at the outer ends thereof. As will be apparent from FIG. 4- a tapered portion of the axial ends of the packer material forming the helical coil 30 are of a reduced dimension to facilitate formation of a uniform cylindrical layer at the axial ends thereof.
Referring to FIG. 5, the circular flanges 36 and 38 of the end collars 32 and 34 are provided with a plurality of circumferentially spaced apertures 40 therethrough. To circumvent premature setting of the packer, metallic wires 41 are threaded through the apertures 40, lengthwise through the wall of the cylindrical layer of the helically wrapped packer coil 30, and are directed through similar apertures in the other end collar. Subsequently, the wire is threaded through an adjacent aperture of the end collar and back through the packer material in a continuous, serpentine manner about the full periphery of the cylindrical wall of the coil 30.
It will be understood that the construction of the packer material forming the coil 30 may be identical to that forming the coil 1 in the embodiment shown in FIG. 1.
Another modified form of a packer according to the present invention is shown in FIG. 6. In this embodiment a cylindrical layer of packer material is formed by a coil of packer material. The coil 50 is formed by a plurality of individual, adjacent split packer rings 52, instead of being helically wrapped. Each ring 52, the circumference of which is split at 45 from the vertical axis, is temporarily installed upon a reduced diameter cylindrical portion 54 of a construction mandrel or jig 56 so that the split, skive cut portions of the individual rings are staggered at 120 relative to adjacent split portions about the periphery of the reduced diameter portion 54 of the mandrel 56. Interposed between the inner cylindrical periphery of the rings 52 and the reduced diameter cylindrical mandrel portion 54 is a cylindrical sheath of aluminum foil 58, or the like, and a second cylindrical sheath 60 of Woven wire sheet asbestos material.
To circumvent premature setting of the packer element, a cylindrical outer sheath of woven wire sheet asbestos material 62 is fixed about the full periphery of the packing material. The outer sheath 62 is provided with radially inwardly projecting end collars 64 at either axial end thereof. The flanges 64 are snugly but temporarily received between the increased diameter construction mandrel portion 65 and an annular mandrel plate 66 having a bore 68 therethrough for reception of a retaining pin 70. The pin 70 is directed through a bore 72 on the outer end of the mandrel portion 54. Suitable adhesive may be applied to the sheath 62 and other elements to retain the same in a desired position.
As will be appreciated a well casing packer according to the embodiments of the present invention shown in FIGS. 1, 4, and 6 are adapted to be installed on a conventional packer mandrel similar to that schematically shown in FIG. 7. The mandrel 80 comprises an increased diameter portion 82 and a reduced diameter portion 84. A bore 86 is provided through the length thereof. A mandrel collar 88 having a bore 90 is movably mounted on the reduced diameter portion 84 so that upon placement of a squeeze-type packer 1 about the reduced diameter portion 84 between the increased diameter portion 82 and the collar 88, relative axial movement may be caused between these latter elements to axially compress and radially expand the packer into sealing contact about the periphery of a well casing 92.
A squeeze-type well casing packer according to the present invention offers significant operational advantages. Primarily, it is not adversely affected by the corroslve or disintegrating actions of well fluids at high temperatures. Further, because of the particular construction of the Well packer materials, packing slippage is circumvented and an efficient and uniform seal is insured upon ax al compression and radial expansion of the packer material coil. Premature packer radial expansion is circumvented by the provision of restraining means to circumvent such premature setting until the desired depth is reached in the well casing.
As will be appreciated, although an aluminum sheath is preferably provided about the periphery of the packer coil shown in the embodiment of FIG. 1, a sheath constructed of rubber or thermosetting plastic may be provided while still achieving certain of the advantages heretofore noted. Further, other metallic substances ma be selected that provide the desired disintegration depending upon the particular environment.
SUMMARY OF MODE OF OPERATION OF INVENTION As will now be recognized, the various embodiments of the apparatus hereinbefore described are characterized by a basic mode of operation.
All of the packers are characterized by superposed portions, which may be separate rings or coil portions of a helix. These packer portions are mounted on a mandrel which may be viewed as an integral portion of a conduit string which serves to move the superposed packer portions longitudinally through a well bore.
In each instance the superposed packer portions are disposed initially in the upper end of a well bore so that these portions are longitudinally interconnected. This longitudinal interconnection may result from an external cylindrical shield such as the cylinder 20 shown in FIG. 1 which engages the exterior of the packer or may result from longitudinally extending and selectively deformable or rupturable wire elements 41 such as shown in FIG. 4. Whether the shield or wire retaining arrangement is employed, the retaining structure is interposed radially between the wall of a well and at least some body portions of the superposed packer portions so as to prevent relative radial movement of these packer portions relative to the well axis.
In the FIG. 1 arrangement, the retaining shield 20 is interposed between the outer periphery of the superposed packer portions and the well bore while in the FIG. 4 arrangement, the retaining wire means 41 is disposed between inner radial body portions of the superposed packer coils and the wall of the well bore.
At this point, it will be recognized that the retaining means interconnects the packer portions in the generic sense that it may peripherally engage and thereby restrain the packer portions as shown in FIG. 1 or be essentially imbedded in the packer portions as shown in FIG. 4. In either event, the retaining means is selectively vitiable in the sense that its retaining effect may be selectively vitiated by the imposition of at least a predetermined, axially directed, packer setting force.
The packer retaining means remains operable, i.e., remains efi'ective to prevent outwardly radial movement of the superposed packer portions while these packer portions are moved longitudinally through a well passage to a selected site.
At the selected site, the retaining effect of the retaining means is vitiated. This is effected by imposing a longitudinal axial setting force on the packer elements sufiicient to overcome the restraining effect of the restraining means. This force, of course, is predetermined so as to be in excess of the force which would expect to be imposed on the packer as the result of the packer encountering obstructions such as casing joints as it was moved through the well bore. With the movement preventing elfect of the retaining means overcome, the packer portions may be expanded radially into engagement with the wall of the well passage.
As will be appreciated, the retaining means may be either yielda-ble or destructible so as to enable their retaining elfect to be selectively overcome. In the case of the shield 20, after the packer has been set, it will be dissolved by well fluids so as to be completely destroyed. Obviously some preliminary destruction or dissolving of the shield 20 may have occurred prior to the setting of the packer shown in FIG. 1. However, it is anticipated that the shield 20 would still be at least substantially intact at the time that the packer shown in FIG. 1 was initially expanded.
While the invention has been described with reference to a preferred embodiment and several modifications thereof, it will be apparent to those skilled in the art that additions, deletions, modifications, substitutions, and other changes specifically described in the illustrated embodiments may be made.
1. In a well system:
a well bore including longitudinal passage means;
means for moving said mandrel means longitudinally through said well passage;
a plurality of longitudinally superposed packer portions mounted on said mandrel means;
destructible retaining means extending entirely longitudinally of said superposed packer portions and interconnecting said superposed packer portions to prevent relative radial displacement thereof, said destructible means being continuously operable while said packer portions are moved longitudinally through said well passage; and
means for vitiating the superposed packer portion retaining effect of said destructible retaining means by at least partially destroying said retaining means after said packer portions have been moved through said well passage to a selected site to allow said packer portions to undergo outward radial movement at said site.
2. A squeeze-type well casing packer adapted to be axially compressed and radially expanded, said packer comprising: a mandrel; a cylindrical layer of packing material formed of a plurality of coils of inorganic packing material mounted about said mandrel, said packing material being in the form of a right-angled parallelogram in cross section and comprising an outer layer of heat resistant inorganic, rough fabric surrounding an inner core of inorganic deformable plastic material; end collars at their axial end of said cylindrical layer of packing material about said mandrel; and destructible restraining means extending from one end collar to the other end collar for retaining said coils of packing material in a radially contracted position prior to selectively radially expanding said packer upon positioning at the desired depth in a well, with said restraining means being destructbile in said well; said packing material being helically wrapped about said mandrel to form said cylindrical layer; each of said end collars having an axially ex tending projection extending towards the other end collar, with said projection overlapping one end of the helically wrapped packing material; and said destructible restraining means comprising an aluminum sheath reactive with well fluids and disposed about the full cylindrical periphery of said packing material and said end collars.
3. A squeeze-type well packer adapted to be axially compressed and radially expanded for setting thereof, said packer comprising: a mandrel; a cylindrical layer of packing material about said mandrel; and destructible means positioned about said cylindrical layer of packing material for retaining said layer in a radially contracted position prior to selectively radially expanding said pack- References Cited UNITED STATES PATENTS Gruber 277203 LeBlanc t 277-229 Roe 277230 Oass 277-229 X Boynton 277-116.8 X Roe 277229 Dean 277203 X Nieison et a1 277-9.5 Tauscher 277203 X Crow et a1. 277-203 X LAVERNE D. GEIGER, Primary Examiner J. S. MEDNICK, Assistant Examiner US. Cl. X.R.