AU737667B3 - Packer assembly and associated downhole tool and wireline grouting system - Google Patents

Description

AUSTRALIA

PATENTS ACT 1990

ORIGINAL

COMPLETE SPECIFICATION PETTY PATENT Invention Title: PACKER ASSEMBLY AND ASSOCIATED DOWNHOLE TOOL AND WIRELINE GROUTING SYSTEM Name of Applicant: INDUSTRIAL INNOVATIONS CONCEPTS PTY LTD The following statement is a full description of this invention, including the best method of performing it known to me/us: -2- Packer Assembly and Associated Down Hole Tool and Wireline Grouting System Field of the Invention The present invention relates to a packer for a hole in the ground, a tool incorporating the packer and wireline grouting system incorporating the packer/tool. The invention further relates to a wireline grouting system which allows a hole to be grouted without requiring a drill string of a ground drill cutting the hole from being withdrawn from the hole.

Background of the Invention It is often necessary during ground drilling to seal off a portion of the hole being drilled.

This portion may run from the toe of the hole to a location towards the mouth of the hole or between two spaced apart points intermediate the toe and mouth of the hole.

There are many different types of packers presently available that can form such seals.

To use a traditional packer, the drill string is first withdrawn from the hole, and the packer lowered into the hole at the location where it is desired to form a seal. Typically, the packer includes a bladder which can be inflated by fluid pumped thereto from the surface through a hose or pipe. However the need to withdraw the drill string significantly increases the time and thus cost for sealing the hole.

When the hole passes through broken or porous ground, in order for the hole to be sealed, in addition to packing it may be necessary to grout the hole. Grouting involves injecting the hole above or below the packer with grout or a like substance to seal the surface of the hole. The grout is injected through a tube passing through the packer. At present however, significant care and skill is required in order to ensure that the grout is not injected at pressure so high that it displaces the packer, but not so low as to provide a non-homogenous grout density.

The present invention was developed with a view to alleviating at least one of the abovementioned problems.

-3- Summary of the Invention According to a first aspect of the present invention there is provided a packer assembly for sealing a hole having a toe and a mouth at opposite ends, said packer assembly including: a body provided with an axial passage; an inflatable bladder disposed about said body; a bypass passage formed in said body, said bypass passages isolated from said axial passage; and having an inlet on a downstream side of said bladder and an outlet on an upstream side of said bladder; a one way inflation valve providing fluid communication between said axial passage and said inflatable bladder to allow fluid to flow in a first direction from said axial passage to said bladder and to prohibit fluid flow in a counter-direction; and, a pressure relief valve for opening and closing said bypass passage, said pressure relief valve automatically opening when fluid pressure applied at said inlet exceeds a predetermined pressure to allow fluid to flow through said inlet, bypass passage and outlet toward the mouth of said hole.

Preferably said pressure relief valve is disposed adjacent said outlet and when said fluid pressure is less than said predetermined pressure, said pressure relief valve closes said outlet.

Preferably said packer assembly further includes, at a downstream end of said axial passage, a minimum pressure valve, said minimum pressure valve opening at a higher pressure than said inflation valve so that fluid flowing into said axial passage initially opens said inflation valve and is diverted into said bladder to inflate said bladder into sealing contact with said hole whereafter, a predetermined increase in fluid pressure causes said minimum pressure valve to open allowing fluid to flow through said axial passage.

Preferably said body includes an inner tube defining said axial passage, and an outer tube co-axially disposed over said inner tube, said bypass passage formed between said inner tube and outer tube, and said bladder disposed over said outer tube.

4 Preferably said one way inflation valve includes a duct open at said axial passage and extending through said outer tube to said bladder.

According to a further aspect of the present invention there is provided a downhole tool including: a packer assembly according to the first aspect of the present invention; and, a container holding a volume of a flowable substance, said container coupled to said packer assembly and in fluid communication with said minimum pressure valve whereby, when said minimum pressure valve is open, fluid flowing through said axial passage flows through the said minimum pressure valve into said container to force said flowable substance from said container.

Preferably said container includes a first removable plug at a downstream end which is forced out of said container by said fluid flowing into said container prior to forcing said flowable substance from said container.

Preferably said container also includes, near an upstream end thereof, a piston, said flowable substance initially confined between said plug and said piston, said piston being slideable towards the downstream end of said container by fluid flowing into said container to thereby force said plug and said flowable substance from said container.

Preferably said tool further includes an upper body having an upstream end and a downstream end, said downstream end of said upper body coupled to an upstream end of said packer assembly; said upper body having a bypass piston adjacent its upstream end, said bypass piston having a peripheral seal for forming a seal against an inner circumferential surface of a transport tube in which said tool can be transported down said hole.

Preferably said tool further includes a releasable latch for coupling said packer assembly to said upper body.

Preferably said releasable latch includes a first part attached to said upstream end of said packer assembly, a second part attached to a downstream end of said upper body for engaging said first part, and a release mechanism disposed in said upper body, said release mechanism moveable under influence of fluid flowing into said upper body through said orifice to a position in contact with said second part to cause the second part to disengage said first part.

Preferably said second part includes a plurality of fingers and bias means for biasing said fingers into engagement with said first part.

Preferably said release mechanism includes a latch release piston moveable between said fingers to cause said fingers to spread apart against said bias means to disengage said first part.

Preferably said first part is in fluid communication with said axial passage and said second part provides fluid communication between said first part and a section of said upper body downstream of said release mechanism.

Preferably said tool includes a volume of an operating fluid filling said axial passage, said first part, said second part, and said second body downstream of said release mechanism.

Preferably said tool is configured so that as said latch release piston slides towards the second part said volume of operating fluid initially opens said one way valves to inflate said bladder to seal against said hole, then said minimum pressure valve opens allowing said operating fluid to flow into said container and force said flowable substance out of said container into said hole and, after said operating fluid forces all the said flowable substance out of said container said latch release piston enters said second part spreading said fingers to release said packer assembly from said upper body.

A wireline grounting system for grouting a hole drilled by a ground drill having a hollow drill string, said drill string having a downhole end and a surface end, said 6 grouting system including: a packer assembly having a body provided with an axial passage and a bladder.

disposed about said body and in fluid communication with said axial passage via a one way inflation valve configured to allow fluid to flow in a first direction from said axial passage to said bladder; and, a transport tube having an outer diameter less than an inner diameter of said drill string in which said packer assembly is loaded for transporting through said drill string to said downhole end, said transport tube further including a coupling member at an upstream end for coupling to a wireline, said packer assembly telescopically extendible from said transport tube to extend into said hole beyond said downhole end of said drill string.

Preferably said wireline grouting system further includes a container holding a volume of grout, said container coupled to a downstream end of said packer assembly and in fluid communication therewith via a minimum pressure valve, said container having an outer diameter less than an inner diameter of said transport tube.

Preferably said wireline grouting system further includes an upper body having an upstream end and a downstream end, said downstream end of said upper body coupled to an upstream end of said packer assembly, said upper body having a bypass piston adjacent its upstream end, said bypass piston provided with a peripheral seal forming a seal against an inner circumferential surface of said transport tube.

Preferably said system includes a stopper case attached to a downstream end of said transport tube, said stopper case having, for a portion of its length, an inner diameter greater than an outer diameter of said peripheral seal to create a gap therebetween when said peripheral seal is located within said portion of said stopper case.

Preferably said bypass piston includes at least one orifice downstream of said peripheral seal, said orifice in fluid communication with said upper body whereby, when said peripheral seal is disposed in said portion of said stopper case, fluid can flow through said gap, past said peripheral seal, into said orifice and into said upper body.

7 Preferably said stopper case includes a first abutment surface downstream of said portion of said stopper case, and said upper body includes a second abutment surface for abutting said first abutment surface to prevent said upper body from wholly withdrawing from said stopper case.

Preferably said system further includes a releasable latch for coupling said packer assembly to said upper body.

Brief Description of the Drawings Figure 1 Figures 2-6 Figure 7 Figure 8 Figure 9 is a section view of a first embodiment of a packer assembly in accordance with the present invention; depict, in section view, an embodiment of a wireline grouting system which incorporates the packer assembly depicted in Figure 1, and in sequentially advanced stages of operation; is a cutaway view of a portion of the wireline grouting system depicted in Figures 2-6; is an enlarged section view of an upper body portion of the wireline grouting system depicted in Figure 2-6 in one stage of operation; and, is a cross-section view of the upper body portion depicted in Figure 8 in a further advanced stage of operation.

Detailed Description of Preferred Embodiments Figure 1 depicts an embodiment of a packer assembly (hereinafter referred to as "packer 10" in accordance with the present invention. The packer 10 is depicted in an inflated state within a hole 12. Packer 10 includes a body 14 provided with an axial passage 16 with an inflatable bladder 18 disposed about the body 14. A bypass passage .20 is.

formed in the body 14 and is fluidly isolated from the axial passage 16. The bypass passage 20 has an inlet 22 downstream of the bladder 18 and an outlet 24 upstream of the bladder 18. A pressure relief valve 26 is supported on the body 14 near the outlet 24 and operates to automatically open the bypass passage 20 when fluid pressure at the inlet 22 exceeds a predetermined pressure. When the pressure relief valve 26 is open, 8 fluid within the hole 12 downstream of the inflated bladder 18 can flow through the inlet 22, passage 20, and outlet 24, back towards a mouth of the hole 12. In this way, fluid pressure downstream of the bladder 18 can be relieved thereby avoiding the possibility of the pressure shifting the packer A one way inflation valve 28 is provided in the body 14 to allow fluid to flow in a direction from the axial passage 16 to the interior of the bladder 18, prohibiting fluid flow in a counter direction. The valve 28 includes a pair of transversely extending ducts to extend between the axial passage 16 and an outer surface of a recess 32 formed on an outer circumferential surface 34 of the body 14. Each duct 30 is open at its radially inner end and thus in fluid communication with the axial passage 16. The radially outer end of each duct 30 is covered by a rubber cuff 36 disposed within the recess 32. When the fluid within the axial passage 16 is of a pressure sufficient to radially expand the cuff 36, the fluid flows from the axial passage 16, through the ducts 30 and into the bladder 18 causing its inflation. However, fluid pressure acting on the cuff 36 from within the bladder 18 simply acts to hold the cuff over the ends of the ducts 30 thereby closing the valve 28.

The body 14 is composed of an elongated inner tube 38 which defines the axial passage 16 and an elongated outer tube 40 coaxially disposed over the inner tube 38. The outer diameter of the inner tube 38 is less than the inner diameter of the outer tube 40 thereby forming an axial space between the two tubes which forms a substantial length of the bypass passage 20. The inner tube 38 extends axially beyond the outer tube 40 at each end. The bypass valve 26 is supported on an upstream end extension of the inner tube 38. Valve 26 includes a compressible annular spacer 42 that fits over the inner tube 38 and a washer 44 disposed between a downstream face of the compressible spacer 42 and adjacent axial face 46 of the outer tube A top cap 48 is coupled to an upstream end of the body 14. The top cap 48 is provided with a skirt 50 within which is housed the compressible spacer 42 and washer 44. The skirt is provided with a plurality of radially extending holes that constitute the outlet 24 of the bypass passage 20. The downstream end of the skirt 50 also acts to clamp an 9 adjacent end of the bladder 18 to the outer surface 34 of outer tube 40. Integrally formed at an upstream end of the cap 48 is a first part 52 of a releasable latch that couples the packer 10 to an upper body 54 of the wireline grouting system 56 depicted in Figures 2-6. The first part 52 together with an adjacent portion of the skirt 50 is formed with an axial passage 58 which is in fluid communication with the axial passage 16. The first part 52 is formed with a barbed head 60 and, downstream of the head 60, a circumferential groove 62 for seating an O-ring 64.

A bottom cap 66 is coupled to a downstream end of the body 14 and is of similar, although not identical, construction to the top cap 48. The bottom cap 66 is also formed with a skirt 68 formed with a plurality of radially extending holes that constitute the inlet 22 of the bypass passage 20. An upstream end of the skirt 68 clamps an adjacent end of the bladder 18 onto the outer surface 34 of the outer tube 40. An integrally formed nozzle 70 extends axially in the downstream direction from the skirt 68. The nozzle 70 has an initial length 72 of constant outer diameter terminating at the upstream end with a bulbous head 74. A passage 76 is formed in the bottom cap 66 in fluid communication with the axial passage 16 and extends through a substantial portion of the length 72 but not through the bulbous head 74. A plurality of holes 78 extend radially through the length 72. Seated over the length 72 and the holes 78 is a further rubber cuff 80. The cuff is maintained on the length 72 by the bulbous head 74. The combination of the holes 78 and cuff 80 forms a minimum pressure valve 82 which, when open allows fluid to flow through the axial passage 16 and passage 76, in a downstream direction. As will be readily apparent, the minimum pressure valve 82 also acts as a one way valve in prohibiting fluid to flow in a counter direction.

Figures 2-6 depict the packer 10 incorporating into the wireline grouting system 56. In Figure 2, the system 56 is shown inside a drill string 84. Coupled to the downhole end of the drill string 84 is a core bit 86. The construction of the core bit 86 is immaterial to the present invention and can be either a standard one piece core bit or of the type used in the RETRACTABIT system described in US Patent No 5,662,182.

The wireline grouting system 56 includes four main components these being the packer 10 transport tube 88, upper body 54 and grout container Referring to Figures 1 and 3, the container 90 is in the form of an elongated tube 92 having an upstream end 94 which is coupled to the bottom cap 66 between the nozzle and the skirt 68 so that the minimum pressure valve 82 is disposed within the tube 92.

A piston 96 is disposed inside the tube 92 toward but inboard of the upstream end 94, to provide a space 98 within which the valve 82 is accommodated. A plug 100 (Figure 3) is provided inside the tube 92 at its downstream end 102. Grouting compound (not shown) is held within the tube 92 between the piston 96 and plug 100.

Referring in particular to Figure 4, the upper body 54 includes, in sequence in the upstream direction, a latch lower housing 104, latch upper housing 106, latch tube 108, packer stopper case 110, and bypass piston 112.

As shown in Figure 1, the lower latch housing 104 is in the form of a short tube 114 having at its downstream end a portion 116 having a stepped decrease in inner diameter.

The portion 116 is provided with an axial hole 118 through which the first part 52 of the latch extends. Coupled to an upstream end of the tube 114 is the upper latch housing 106. An internal annular flange 120 is formed inside the body 106 upstream of its downstream end 122. The inner circumferential surface of the flange 120 defines a hole 124.

Retained between the portion 116 and the flange 120 is a second part 126 of a releasable latch. The second part 126 comprises four fingers 128 disposed side by side in a circular fashion.. The fingers 128 are biased together by a plurality of rubber bands 130 which sit within respective grooves 132 formed at axially spaced apart locations on an outer surface of the fingers 128. The radially inside surface of each finger 128 is formed with a rebate 134 inboard of the downstream end for receiving the barbed head 60 of the first part 52. It will also be noted that a fluid flow channel 136 is formed inside of the fingers 128 providing fluid communication with the passage 58. Upstream end 138 of the housing 106 is threadingly coupled to downstream end 140 of the latch tube 108.

11 Threadingly coupled to an upstream end 142 of the tube 108 is the packer stopper case 110. As shown most clearly in Figures 8 and 9, the packer stopper case 110 has a band 144 starting from downstream end 146 which has an outer circumferential surface of constant diameter. However upstream of the band 144, the packer stopper case 110 is provided with two contiguous bands 148 and 150 of increased diameter. The increase in diameter from the band 144 to the band 148 is provided by a circumferential tapered shoulder 152 while the increase in diameter from the band 148 to the band 150 is provided by a circumferential tapered shoulder 154. A circumferential groove 156 is formed in the band 150 and seats an O-ring 158 which forms a seal on the inside surface of the transport tube 88.

A latch release piston 160 is initially housed within the packer stopper case 110 as shown in Figures 2, 3, and 8. Adjacent the bypass piston 112. The piston 160 is provided with a head 162 at an upstream end formed with a circumferential groove 164 for seating an O-ring 166 creating a seal with inner circumferential surface of the packer stopper case 110, tube 108 and housing 106. The piston 160 also includes a pin 168 extending axially in a downstream direction from the head 162 and terminating in a reduced diameter nose 170.

As further shown in Figures 8 and 9, abutting an upstream end of the packer stopper case 110 is the bypass piston 112. The bypass piston 112 is in the form of a short tube having a centrally located internal dividing wall 172. Outer surface 174 of the piston 112 is provided with two reduced outer diameter portions 176, 178 on either side of the wall 172. 0-ring 180 is seating in a circumferential groove 182 in the surface 174 coincident with the location of the wall 172.

A first set of radially extending holes 184 is formed through the reduced diameter portion 178 while a second set of radially extending holes 186 are formed through the reduced diameter portion 176. While the piston 112 is within the transport tube 88 the O-ring 180 effectively seals the holes 184 from the holes 186.

Attached to a downstream end of the transport tube 88 is a stopper case 188 (refer 12 Figures 8 and The stopper case is in the form of a short tube 190 having an upstream portion 192 formed with a constant inner diameter greater than that of the transport tube 88. More specifically, as shown in Figure 9, the inner diameter of the portion 192 is selected so that when the O-ring 180 is in the portion 192 an annular gap 193 is formed between the O-ring 180 and the portion 192 providing a fluid flow path between the holes 184 and 186. Travelling in the downstream direction, from the portion 192, the tube 190 has a portion 194 of steadily decreasing inner diameter, a portion 196 of constant inner diameter, a tapered portion of reducing inner diameter forming a circumferential shoulder 198 and a further portion 200 of constant inner diameter.

The operation of the wireline grouting system 56 will now be described with particular reference to Figures 2-6, 8 and 9.

The wireline grouting system 56 is shown in use with a core drill having a hollow drill string 84 with a core bit 86 coupled at a downhole end. The transport tube 88 incorporated in the system 56 is a conventional core tube used in a core drill system. An upstream end of the transport tube 88 is coupled using a conventional back end or head assembly to a wireline. In this way, the system 56 can be used with any commercially available core drilling system. The only modification required is to remove the core tube lifter case (not shown) from the downstream end of the tube 88 and replace it with the stopper case 188.

Initially, the container 90 is filled witl grout between the piston 96 and plug 100, the bladder 18 is deflated and the latch release piston 160 disposed near an upstream end of the packer stopper case 110. The passage 76, axial passage 16, passage 58, channel 136, and interior of the upper latch housing 106, and latch tube 108 are prefilled with liquid, typically water. The container 90, packer 10, upper body 54 and bypass piston 112 are all disposed inside the transport tube 88 and stopper case 188. This configuration is shown in Figure 2.

The transport tube 88 is then lowered through the drill string 84 by a wireline. The ensemble of the container 90, packer 10 and upper body 54 is held within the tube 88 by 13 the friction created by O-rings 158 and 180. The descent of the transport tube 88 within the drill string 12 is stopper by abutment of an upper end of the tube 88 with the landing ring (not shown) in the normal way in which the descent of a core tube within a core drill is halted. When this occurs, the downstream end of the system 56 is located inside the downhole end of the drill string 84.

1 Figure 3 depicts the next stage in the operation of the grouting system 56. Once the descent of the tube 88 has been halted, an operator on the ground pumps fluid, typically water or drilling mud into the drill string 84. This fluid exerts a force in the downstream direction on the bypass piston 112. Because of the seal created by the O-ring 180 while the bypass piston is within the transport tube 88, the fluid is prevented from flowing past the piston 112. Accordingly the pressure exerted by the fluid pushes the piston 112 in the downstream direction which consequently telescopes the container 90, packer assembly 10 and upper body 54 from the downhole end of the drill string 84 as depicted in Figure 3. This telescoping is halted when the shoulders 154 and 198 come into mutual abutment as shown in Figure 9.

When the piston 112 enters the stopper case 188 (shown in Figures 4 and 9) the fluid pumped from the surface flows through the first set of holes 184, gap 193 past the 0ring 180, and through the holes 186 into the packer stopper case 110.

The fluid now entering the packer stopper case 110 forces the latch release piston 160 to slide in the downstream direction toward the packer assembly 10. The one way inflation valve 28 and minimum pressure valve 82 are arranged so that valve 28 opens at a lower pressure than valve 82. Therefore as the piston 160 slides in a downstream direction, the liquid initially contained with in the wireline system 56 opens the valves 28 causing the bladder 18 to inflate and seal against an inner surface of the hole 12.

With the bladder 18 inflated to its maximum extent, and the valve 82 closed, the latch release piston 160 remains stationary while fluid pressure upstream of the piston is increased by the operator. Eventually the pressure is increased to the extent so as to cause the valve 82 to open. Once this occurs, the fluid within the wireline grouting 14 system 56 can flow through the holes 78 into the space 98 and act on the piston 96. The fluid pressure causes the piston 96 to start moving in the downstream direction forcing the plug 100 and grout from the downstream end 102 of the container 90. This stage of operation is depicted in Figure If the volume of the hole downstream of the inflated bladder 18 is less than the volume of grout held within the container 90, the grout together with the liquid prefilled in the wireline grouting system 56 exerts a pressure on the inflated bladder 18 as well as on the pressure relief valve 26 via inlet 22 and passageway 20. If the pressure of this grout/liquid exceeds the opening pressure of the valve 26, some of the grout/liquid is able to compress the compressible spacer 44 providing a gap to flow through the passage 20 and outlet 24 into the hole 12 upstream of the bladder 18. Depending on the relative volumes of the grout and the portion of the hole downstream of the bladder 18, as well as the condition of that portion of the hole, it may well be that the pressure of the grout and other liquid downstream of the bladder 18 does not become sufficiently high to open the bypass valve 26.

The fluid acting on the upstream end of latch release piston 160 continues to force the piston 160 to move in the downstream direction and to eventually enter in between the fingers 128 as depicted in Figure 6. This causes the fingers 128 to spread apart against the bias of the rubber bands 130 thus decoupling the fingers 128 from the latch portion 52. At this position, the piston 160 also seals the latch tube 108. This is indicated by a stepped increase in the pressure upstream of the piston 160 which would be observed by the drill operator. At this point in time, the operator can then withdraw the transport tube 88 and upper body 54 leaving the inflated packer 10 and container 90 in the hole.

These components of the wireline grouting system 56 are most conveniently made from plastics materials and/or aluminium which can be easily drilled through using conventional drill bits. Thus, once the grout has had sufficient time to set, the drill operator can then operate the drill in the normal manner and drill through the packer assembly 10, container 90 and grout.

As is apparent from the above description, embodiments of the present wireline grouting 15 system 56 allow the hole to be packed and grouted without tripping the drill string 84.

Further, the system 56 can be used with conventional core drilling equipment. The provision of the bypass valve 26 prevents the situation where the pressure of grout injected into the hole may be so great as to physically displace the packer Additionally, the inclusion of the bypass valve 26 assists in ensuring that the grout when in the hole is of a homogeneous density. System 56 is also ideal for allowing an intermediate section of the hole to be grouted. This can be done by initially deploying the system 56 without a container 90, inflating the bladder 18 and then releasing the packer assembly from upper body 54 leaving it in the hole, lifting the drill string 84 to a position above the upper end of the intermediate portion of the hole to be grouted, then deploying a second wireline grouting system 56 with container 90, and operating the system 56 to inflate the bladder 18 and inject the grout from the container 90 into the intermediate portion of the hole between the two inflated bladders 18.

Now that the embodiment of the present invention has been described in detail it will be apparent to those skilled in the relevant arts that numerous modifications and variations may be made without department from the basic inventive concepts. For example, in the present description, the container 19 is described as containing grout between the piston 96 and plug 100. However any other type of flowable substance which is desired to be delivered to part of a hole can be loaded into the container 90. Additionally, the packer assembly 10 is shown as having a single inflatable bladder 18. However multiple bladders can be provided along the body 14, with corresponding inflation valves 28. Also while the bypass piston 112 is shown as a separate item which abuts the stopper case 112, the two components can be integrally formed.

Such variations and modifications together with others that would be obvious to a person of ordinary skill in the art are deemed to be within the scope of the present invention the nature of which is to be determined from the above description.

Claims (3)

1. A packer assembly for sealing a hole having a toe and a mouth at opposite ends, said packer assembly including: a body provided with an axial passage; an inflatable bladder disposed about said body; a bypass passage formed in said body, said bypass passage isolated from said axial passage, and having an inlet on a downstream side of said bladder and an outlet on an upstream side of said bladder; a one way inflation valve providing fluid communication between said axial passage and said inflatable bladder to allow fluid to flow in a first direction from said axial passage to said bladder and to prohibit fluid flow in a counter-direction; and, a pressure relief valve for opening and closing said bypass passage, said pressure relief valve automatically opening when fluid pressure applied at said inlet exceeds a predetermined pressure to allow fluid to flow through said inlet, bypass passage and outlet toward the mouth of said hole.

2. A packer assembly according to claim 1 further including at a downstream end of said axial passage, a minimum pressure valve, said minimum pressure valve opening at a higher pressure than said inflation valve so that fluid flowing into said axial passage initially opens said inflation valve and is diverted into said bladder to inflate said bladder into sealing contact with said hole whereafter, a predetermined increase in fluid pressure causes said minimum pressure valve to open allowing fluid to flow through said axial passage.

3. A packer assembly according to claim 2 wherein said body includes an inner tube defining said axial passage, and an outer tube co-axially disposed over said inner %\PERTHOI~moSJaryer wpstp IS- Amedcd aa Indu tCija InnvMions do I26dW 17 tube, said bypass passage formed between said inner tube and outer tube, and said bladder disposed over said outer tube. Dated this 28 t day of February 2001 INDUSTRIAL INNOVATIONS CONCEPTS PTY LTD By Its Patent Attorneys GRIFFITH HACK Fellows Institute of Patent and Trade Mark Attorneys of Australia