Abstract:
An improved packer apparatus used for isolating portions of a drill hole or the like while providing an inner passageway for fluid communication and/or access between selected areas within the hole. An improved head design providing for an inner passageway of relatively greater diameter and facilitating the use of adapters for multiple packer applications is disclosed. Novel inflation means for inflating a packer gland are described. An improved reinforced packer gland is also described.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to packers used for isolating portions of a drill hole or the like and more particularly, to inflatable packers of the type having an expandable gland which may be inflated by a fluid to cause the gland to engage the surface of the surrounding hole in sealing relationship. 
     An inflatable packer of the type presently known in the art consists generally of an elongate, rigid, inner tubular member having packer head members mounted at either end. Packer head members are generally annular in shape having diameters substantially exceeding that of the inner tubular member. Opposite ends of a tubular gland member are generally sealed to the outer annular surfaces of the head members thereby enclosing the inner tubular member within the gland member and forming an annular cavity between opposed surfaces of the inner tubular member and gland member. The internal tubular member provides structural integrity to the packer and may also accommodate the flow of fluids or interior pipe or wire placement or the like. The annular cavity between the gland member and the inner tubular member may be inflated with air to cause the packer element to expand and engage the surface of a hole, pipe casing, or other surrounding surface in which it is enclosed. 
     Inflatable packers have been used in a variety of applications to bring about a supportive or sealing contact between the packer gland and a portion of an elongate hole while simultaneously providing means for access to various zones along the length of the hole through the packer inner tubular member. For example, inflatable packers have been used to support sealed sections of casing pipe or drill pipe or a tubing string within a borehole. Packers have also been used to support an inner tubing string within an existing outer tubing string. Inflatable packers have been used to isolate zones within a borehole for testing, pumping and sampling purposes and as an integral part of pneumatic sampling and pumping systems. Packers have also been used to plug off a portion of a hole or pipe or alternately, to seal off a leaking portion of a sewer or waterpipe while simultaneously providing a fluid passage therethrough by means of two packers, one positioned on either side of the leak, and conduit supported between the packers. Packers have also been used in numerous other applications well known in the art. Prior to the present invention, each different use generally required a different type of packer. 
     With prior art packers, the packer heads have been considerably larger in diameter than the inner tubular member in order to provide sufficient strength to couple the packer to other connecting elements while simultaneously providing an attachment surface for the gland member. The problem with such an arrangement lies in the fact that the overall dimensions of the packer at the point of connection of the gland member to the packer heads is considerably larger than the diameter of the inner tubular member. Thus, there is a great size differential between the diameter of the passage provided through the packer by the inner tubular member and the diameter of the surrounding hole. This size reduction in the packer passage, of course, limits the amount of test conduit, etc. which can be inserted through the inner passage or in case of pumping operations, greatly limits the fluid flow rate through the hole because of the restriction produced by the packer. 
     In existing packers testing cables, air lines, etc., are often passed through conduit positioned in peripheral bores in the head members and extending between the heads through the annular cavity created by the gland and the inner tubular member. The placement is necessitated because of the lack of space within the inner tubular member. As a result, most such packers can only be used for a single purpose because of their fixed conduit configurations. 
     The inflatable gland of the packer has caused problems because of its tendency to rupture at high pressures or when encountering sharp or uneven surfaces of the type often associated with boreholes through rocky layers. The use of reinforcing material has met with only partial success in the past due to the fact that the reinforcing material, if sufficiently strong to prevent rupture of the gland has proven to be too unyielding to provide adequate inflation in many circumstances. 
     Thus, a need exists for a packer having an inner passageway of a greater diameter with respect to the packer outer diameter for providing improved fluid flow capacity or instrument placement within the packer. Such a packer should be adaptable to multiple uses and easily converted from one use configuration to another without major structural modifications. It is also desirable to provide a packer having a reinforced gland member which is capable of being inflated to high pressures and used against uneven or rough surfaces without rupture while simultaneously providing sufficient expansion to cause proper sealing engagement with a surrounding hole. 
     SUMMARY OF THE INVENTION 
     The present invention comprises an inflatable packer having an inner tubular member, two head members and an encompassing gland member. The head members are attached to either end of the inner tubular member and the gland member is attached at each end to a portion of each head member. Each packer head member comprises a body portion having an interior cavity therein and an elongate sleeve portion extending axially inwardly from the body portion. Each head member has an inner passageway therein coaxial and of substantially equal diameter to that of the passageway in the body portion. The outer diameter of the sleeve portion is substantially smaller than that of the outer diameter of the body portion and comprises the mounting surface for the gland member. The inner tubular member comprises exterior threads on at least one end thereof which are mateable with the interior threads provided in the inner passageway of the body portion of at least one of the packer heads. The gland member is mounted on the outer surface of the sleeve portion of each packer head by band means or the like providing a reduced packer diameter with respect to packers of conventional construction due to the reduced diameter of the sleeve portion with respect to the diameter of the body portion of each head. In one embodiment both packer heads are attached to opposite threaded ends of the inner tubular member in the manner above described. In another embodiment one of the packer heads is provided with O-rings at the surface of the inner passage of the body portion whereby sliding sealing contact between the packer head inner passage and the outer surface of the inner tubular member is provided. The latter embodiment may be used in association with a reinforced gland element to allow the gland to progressively shorten in length as it expands during inflation. 
     The gland member may be inflated by air or other fluid provided through a fluid passageway in at least one of the two packer heads. The passageway may comprise a bore through the body portion of the head which intersects one of the head inner passage at a point axially inward of the area of threaded attachment of the head and inner tubular means. The bore may be provided in a generally axially extending direction entering the body portion at the end surface thereof and being intersected by a second generally radially extending bore. In another embodiment, the bore may be directed generally axially with a slight radially inward inclination to provide intersection with the inner passage at the aforementioned point. The surface of the head inner passage and the outer surface of the inner tubular member define an annularly shaped second portion of the fluid passageway which is in fluid communication with the first portion defined by the above described bores. Fluid under pressure may be directed through the bores and annular passageway formed by the surfaces of the sleeve and inner tubular member to inflate an inflation chamber defined by the inner surface of the gland member and outer surface of the inner tubular member. This inflation chamber, during deflated conditions, comprises a very thin annular volume having a thickness substantially equal to that of the sleeve portion of the head. Thus, by providing a thin sleeve for gland attachment, the total diameter of the apparatus is reduced with respect to conventional apparatus. The sleeve also coacts with the bore in the body to allow inflation of the packer without separate conduit. Thus, the sleeve portion serves the dual function of gland inflation means and gland attachment means and achieves the result of minimizing the external diameter of the packer with respect to the tubular passageway provided in the inner tubular member. The relatively larger diameter of the passage through the inner tubular member achieved by the improved head design allows all instrument and air conduit, etc. to be passed through the inner tubular member rather than between the inner tubular member and the gland as in some conventional designs. As a result, screw-in head caps of various configuration may be inserted in one or both heads to change the packer internal passage configuration to provide for multiple applications. 
     The gland member in a reinforced embodiment thereof comprises an inner bladder layer formed from a resiliently expansible substance such as rubber or the like. A second layer is formed by a reinforced wrap wound at a predetermined angle with respect to the longitudinal axis of the gland member. A third layer is formed from reinforced wrap of identical material as used in the second layer and provided at an orientation opposite that to the second layer. It has been found that such a wrapping allows the wrap material to change in three-dimensional orientation with respect to the axis of the gland member as the gland expands in such a manner as to create an increased gland diameter in association with a decrease in gland length. Such an orientation is produced by a shifting in the position of the wrap without an extension or contraction along the longitudinal axis of the wrap itself. Thus, such a wrapping configuration may be provided using a high strength, non-stretching material such as the steel belting material used in automobile tires, aramid, or the like. A third, fourth and subsequent pairs of wraps may be provided as required to change the expansion characteristics of the gland member and to provide additional resistance to rupture. 
     Thus, it is an object of the invention to provide an inflatable packer having an improved head configuration which allows the internal diameter of the packer to be maximized with respect to the outer diameter of the packer. 
     It is another object of the invention to provide an improved packer which may be used as a fixed end packer or as a movable end packer. 
     It is another object of the invention to provide a packer having a reinforced bladder which is resistant to rupture and yet sufficiently extensible to produce a proper seal at the surface of a surrounding hole. 
     It is another object of the invention to provide a packer which may be used in multiple applications without modification to the basic packer design. 
     It is another object of the invention to provide a packer which may be produced at a relatively low cost. 
     It is another object of the invention to provide a packer which may be provided in multiple lengths and with glands having multiple pressure ratings. 
     It is another object of the invention to provide packers that may be ganged together to pack off a length of hole. 
    
    
     BRIEF DESCRIPTION OF DRAWING 
     An illustrative and presently preferred embodiment of the invention is shown in the accompanying drawing in which: 
     FIG. 1 is an exploded perspective view of a packer apparatus; 
     FIG. 2 is a plan view of a moveable end packer in a deflated condition; 
     FIG. 3 is a plan view of a moveable end packer in an inflated condition; 
     FIG. 4 is a plan view of a fixed end packer in a deflated condition; 
     FIG. 5 is a plan view of a fixed end packer in an inflated condition; 
     FIG. 6 is a cross-sectional detailed view of one end of a packer of the type illustrated in FIG. 1; 
     FIG. 7 is a detailed cross-sectional view of a portion of a packer head; 
     FIG. 8 is a detailed cross-sectional view of a sliding end packer head; 
     FIG. 9 is a detailed cross-sectional view of a portion of a packer head; 
     FIG. 10 is a cut-a-way prospective view of a packer gland; 
     FIG. 11 is detailed plan view of a portion of a packer gland; 
     FIG. 12 is a detailed planned view of another portion of a packer gland; 
     FIG. 13 is a cross-sectional end view of a packer gland; 
     FIG. 14 is a perspective view of a packer adapter plug; 
     FIG. 15 is a perspective view of another embodiment of a packer adapter plug; 
     FIG. 16 is a schematic drawing showing the use of packers to isolate various zones within a borehole for water sampling; 
     FIG. 17 is another schematic drawing showing detail from a portion of FIG. 16; 
     FIG. 18 is a schematic drawing showing the use of multiple instruments in a portion of the drill hole isolated by two packers; 
     FIG. 19 is a detail cross sectional view of a portion of a packer head. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As illustrated generally by FIG. 1, the packer apparatus comprises an inner tubular means 12 having a cylindrical outer surface 13 and a cylindrical elongate passage 14 extending therethrough. Tubular means 12 is constructed from a high strength structurally rigid member such as standard pipe or the like and in one embodiment comprises a threaded end portion 15, 16 at either end thereof. A first head means 18 which allows coupling of the inner tubular means 12 to associated structure, such as pipe 20, has a longitudinally extending body portion 22 with a generally cylindrical outer surface 23. A longitudinally sleeve portion 26 is integrally formed or otherwise rigidly attached to the body portion 22 and comprises a cylindrical outer surface 28 which intersects an annular axially facing abutment surface 30 of the body portion 22. A central elongate cylindrical passage 32 extends longitudinally through the first head means 18 and comprises a threaded passage portion 34 adjoining a smooth passage portion 36 as illustrated in FIG. 6. The threaded passage portion 34 is positioned generally within the body portion 22 and the smooth passage portion 36 is positioned generally within the sleeve portion 26 extending a short distance beneath the body portion 22. As illustrated by FIG. 8, a second head means 40, positioned at the opposite end of inner tubular means 12, FIG. 1, has the same general exterior construction as the first head means having a sleeve portion and a body portion 41, 42 with a cylindrical sleeve outer surface 43 and cylindrical body outer surface 44. A longitudinally extending central cylindrical passage 33 passes from end to end of the second head means 42 and may comprise various attachment means for sealingly attaching the second head means 42 to the intertubular means 12. As illustrated in FIG. 8, the attachment means may comprise O-rings 46 positioned in parallel O-ring annular grooves 45. The O-rings 46 provide sealing engagement with the outer surface 13 of intertubular means 12. As illustrated by FIG. 8, a wiping means such as annular wiping ring 48 may be provided in an annular wiping groove 47 and head portion 44 for the purpose of wipingly cleaning the outer surface 13 of tubular member 12 as the head 40 slides back and forth thereon. In another embodiment of the second head means 40 as illustrated in FIG. 9, the inner passage 33 comprises a threaded portion 35 positioned within body portion 42 which is matingly connected to threaded portion 16 of inner tubular member 12. The second head slideable attachment means shown in the embodiment of FIG. 8 is used in association with a slideable end packer and the second head means fixed attachment means which is illustrated in the embodiment of FIG. 9 is used in association with a fixed end packer as described in further detail hereinafter. As shown by FIG. 1, a cylindrical gland means 50 having a cylindrical outer surface 52 and cylindrical passage means 54 extending from end to end thereof may be constructed in a series of layers as illustrated by FIGS. 10-13. In the embodiment illustrated in FIGS. 10-13 the gland member comprises an inner bladder element 51 constructed from a resilient material such as rubber or the like which is inflatably and deflatably extendable and substantially fluid impermeable. The bladder element 51 serves the purpose of retaining a fluid therein as discussed in further detail hereinafter while the outer layers 53-61 function to prevent rupture of the inner bladder 51. As illustrated by FIG. 11, a second layer is formed by means of a tape like wrapping material 53 which is wound about the bladder 51 at an acute angle &#34;a&#34; with respect to the longitudinal axis XX of the gland 50. A second layer formed by wrapping material 55 is reverse wound with respect to the first layer 53 by positioning it at angle &#34;a&#34; with respect to the longitudinal axis XX but in the reverse direction from the first material 53. The cross wrapping of layers 53, 55 allows the gland 50 to expand in a radial direction while shortening in a longitudinal direction by a shifting relationship between the wrap layers 53, 55. Thus the material used in wraps 53, 55 need not be longitudinally extensionable about its own axis and may comprise a reinforced wrapping material such as aramid or steel reinforced belting having longitudinal wire members 63 passing therethrough as illustrated in FIG. 13. The packer may be additionally reinforced by further layers of wrapping (not shown) positioned at substantially the same angle &#34;a&#34;. The additional wraps enable the packer to withstand rupture either from a roughened surface into which it comes in contact or from the internal pressure within the gland itself. The packer inflation characteristics may be varied by wraps 57, 59 positioned at acute angle &#34;b&#34; with respect to longitudinal axis XX and extending only a few inches inward from the gland ends 56, 58. By changing the wrap angle &#34;b&#34;, and length of the wraps, the inflation contour of the packer may be varied to achieve a predetermined shape as required for various conditions. In one preferred embodiment, the first two wraps 53, 55 are provided at an angle &#34;a&#34; of substantially 25 degrees and the second pair of short length wraps 57, 59 are provided at an angle &#34;b&#34; of substantially 35 degrees. 
     As illustrated by FIG. 6 and FIG. 8, the end portions 56, 58 of the gland 50 are sealingly mounted to the outer cylindrical surface 28, 43 of sleeve portions 26, 41 respectively by sealing band means 66, 68. The sealing band means 66, 68 may be of in a conventional type which apply radially inwardly directed compressive force against the gland end 56, 58 and sleeves 26, 41. As illustrated by FIG. 6, a gas chamber means 70 is defined by the inner cylindrical surface 72 of gland 50 and outer cylindrical surface 13 of inner tubular means 12. During a deflated condition, as illustrated generally by FIGS. 6, 2 and 4, the surfaces 71, 13 may be in touching contact but as air or other fluid fills the chamber 70, it expands as illustrated generally by FIGS. 3 and 5 pressing the outer surface 52 of the gland 50 against the wall of the surrounding hole 100 as illustrated generally in FIGS. 16-18. 
     Fluid is provided to the inner chamber 70 by means of an air passage represented generally by axially extending bore 80, radially extending bore 82 and annular passageway 84 in FIG. 7 and 19 and by axially extending radially inclined bore 81 and annular passage 84 illustrated in FIG. 6. The annular passageway 84 is defined by the inner surface 72 of sleeve 26 and the outer surface 13 of inner tubular member 12. In one preferred embodiment the dimension of the annular passageway 84 is approximately 0.010 inches. The portion of the passageway intersecting the outer surface of body member 22 may be connected to air conduit as by screw and nipple means 88 and 89 mounted at the end surface of body portion 22 illustrated generally in FIG. 6. Alternately, a fluid conduit 86 may be rigidly mounted within the bore 80 as illustrated in FIG. 7 and connected to an air line 110 as by conventional coupling means 89, FIG. 3. 
     As illustrated in FIGS. 2 and 3, the packer may be constructed with one moveable end such as the type shown in FIG. 8 and 18 whereby a reinforced bladder 50 of the type illustrated in FIGS. 10-13 may be provided to prevent rupture of the internal bladder element 51. As illustrated in FIGS. 4 and 5, a packer 10 with two fixed heads 18, 40, such as illustrated in FIGS. 6 and 9, may also be used for various design and application considerations. 
     As illustrated in FIGS. 16 and 17, the present packer apparatus 10 allows multiple conduit 115 and multiple air line conduit 116 to be passed through the interior thereof for purposes such as for example sampling water quality at various zones 118, 119 within a bore hole 100. The basic packer apparatus 10 illustrated in FIGS. 1-9 may be adapted for such use by employing a multiple conduit adapter head cap 130 as illustrated in FIG. 15. The adapter 130 may be threaded 138 to allow connection to head 18 and may comprise a plurality of transverse bores 32 therethrough to accommodate conduit 115 having substantially similar outer diameters to that of the inner diameters of the bores 132. Air supply passages 134 for providing air or other fluid to expand the bladder 50 of each packer 10 through air line conduit 116 may be provided in the adapter 130. Each adapter bore 134 may be provided with sealing means such as O-rings or the like (not shown) or threading attachment means (not shown) to sealingly secure the conduit passing therethrough as required by a specific application. 
     In a slightly different embodiment as illustrated by FIG. 18, a single packer may be provided with a threaded adapter head cap 140, FIG. 14, having external threaded portion 141 and inner threaded conduit bores 144 positioned therein for securing conduits 145 used for various functions such as pump effluent passage, electrical wire and the like. Various other adapters may of course be used depending upon the use of the packer apparatus 10 are and within the scope of the invention. 
     It is contemplated that the inventive concepts herein described may be variously otherwise embodied and it is intended that the appended claims be construed to include alternative embodiments of the invention except insofar as limited by the prior art.