DEPTH DISCRETE MULTI-LEVEL DOWNHOLE SYSTEM FOR GROUNDWATER TESTING

AND MANAGEMENT

FIELD OF THE INVENTION

The field of this invention is improved systems for groundwater testing and management. The system is for groundwater use downhole in drilled borehole situations and more particularly borehole systems elements which combine to provide for ready and quick manufacture and assembly, long term depth-discrete utility downhole and particularly, when coupled with increasingly sensitive measuring equipment over an increasingly dense discrete series of strata, and highly ensured removability.

BACKGROUND OF THE INVENTION

Packers and plugs are used downhole in groundwater testing and management to isolate zones and to seal off parts or levels of or entire boreholes or wells. The boreholes in question are drilled in the manner of a well, for example for the purpose of testing for contaminants that may be present in groundwater. There are many styles of packers on the market. Some are inflatable, while others are mechanically set into contact with a surrounding tubular drilled hole.

More recently, increasing sensitivity to groundwater quality testing, improved instrumentation and long term environmental factors over multiple strata have provided an increasing demand for a simple downhole system. This must be simple to manufacture and to use and it may be required to remain insitu effectively for long periods with a high quality dependable seal and then be removable.

The requirements for depth-discrete information over multiple strata stetin conflict with cost and environmental concerns, particularly as they relate to the size (diameter/depth) of individual boreholes and/or the number of boreholes required for borehole field effective for measurement and evaluation. On the one hand multiple pathways and tools must be provided over large distances which must remain within a very small diameter hole. Increasing density in both cross- section and axially plus cost/time constraints put a very high premium on simple solutions which are field adaptable. This premium which has not been fully satisfied to date.

The general construction of such packing-seals (packers), for use in a groundwater sampler, may be described as follows. The sampler itself includes a tube of PVC or other suitable material which is placed axially down into the borehole. The tube contains one or several sampling ports along its length, which are placed at predetermined depths in the borehole to sample the groundwater conditions at that discrete level.

Each sampling port is sealed off from the remainder of the borehole by respective packing seals, placed above and below the sampling port. The (vertical) distance apart of the packing-seals may range from a few centimeters to several meters.

Such packing seals have the requirement to be able to follow the borehole while the tube is being inserted and then expand when in place without damage. When the tube is being lowered into the hole, the packing-seal must be clear of the highly abrasive, somewhat irregular and cutting walls of the borehole. Once the packing-seal is in position at the correct depth, the packing-seal must expand into intimate sealing contact with the irregular borehole wall and remain in sealing contact for considerable periods of time.

Packing-seals may or may not be designed to be retrievable from the borehole.

Attention is now directed to the manner in which a packing-seal cooperates with the borehole. The groundwater borehole is drilled into the ground that is being sampled. It is normally the case that the type of ground from which the samples are to be taken is the kind that includes several different discrete stratas which are highly irregular both within and among the various strata, with various faults and pockets, because that is the kind of ground that is most apt to lead to the spreading of contaminants in the groundwater. Under these conditions, the packing-seal is required to seal against what may be a very imperfect borehole- wall surface after surviving the trip downhole from the surface and then last for a lengthy service period or permanently. The requirements of the seal to provide a complete and reliable constraint against leakage of groundwater past the seal are quite stringent and becoming more so at an ever-increasing rate. If the seal leaks at any time in its service lifetime, there is often no way of discovering the fact that a leak is developing or has occurred. The sampler apparatus continues to allow a sample of the water to be taken at the sampling port, and the analyst has no way of knowing that the water in the sample may have leaked in from a different depth.

More recently, packers have been used that employ elements which respond to fluids and swell to form a seal. Different materials have been disclosed as capable of having this feature. Some designs have gone further to prevent or restrict swelling until the packer is close to the final position where it will be set. These designs are still limited in the amount of required swelling from the sealing element due to limitations in the developed contact pressure against the surrounding tubular wall. The amount of contact pressure is a factor in the ability to control the level of differential pressure. In some designs there are also issues regarding extrusion of the sealing element in a longitudinal direction as it swelled radially but no solutions have been offered.

In a prior patent, USP 5,048,605, issued September 17, 1991 , a double layer rubber sleeve stet driven outward by a expansible annular member co-axial with the borehole. A Kevlar™ layer in the form of a sheet with its ends overlapped was placed between the rubber layers. The annular member expanded in contact with water once located in its downhole location. As the expansion pressure increased the main body of the annual member encountered sufficient back pressure resistance from the borehole itself and clamped the Kevlar™ layer. Thus clamped, the Kevlar™ layer would form restraining bridges over small areas of deformity in the borehole walls.

This description in USP'605 is aimed at providing, without undue expense, a packing-seal in which the analyst may have a high degree of confidence that each of the packing-seals is actually sealing, even though the analyst knows that the borehole wall surface may be imperfect due to fissures, faults, pockets, minor cave-ins, non-cohesive material, and the like, and that any such imperfections are neither regular or consistent axially along the vertical line of the borehole.

A popular material for this purpose is Bentonite™. That and other water- expandable materials expand with a considerable force. If the borehole wall surface is strong, the Bentonite™ may, be laterally-speaking, contained, and will be restrained from further expansion by compressing the outer layer against the irregular wall to the expansion limit. But if the wall surface is locally very weak, or not present, the Bentonite™ will continue to expand, with only the rubber sleeve to contain it.

Thus, if the rubber sleeve is too thin, the sleeve may burst if it expands into a fissure, and will leak. If the sleeve is too thick, the sleeve will not conform sufficiently to minor irregularities, and again will leak. This compromise over the properties of the packing-seal has meant that samples taken from boreholes with imperfect surfaces, using conventional sampling apparatus, have been unacceptably unreliable in today's terms and raise short and long term functional and environmental concerns.

In any case, the Bentonite™ is known to expand axially, as well as radially, where it works against the sealing ends of the rubber layers. Capturing the Kevlar™ layer does not show an effective solution for today's uses as large uncontrollable forces are developed within the Kevlar™ and Bentonite™ layers which interfere with long term and leak free sealing of the rubber containment layers. Experience shows that such captured Kevlar™ layers are prone to contribute to sealing failures and loss of sealing integrity within and between the rubber layers and between the rubber layers and the tube.

In Fig 7 A shows a fully assembled and installed downhole sampling system as of the invention extending from terminal cap 16 up through a variety of sampling casings 15 located in respect of sampling zones to associated with downhole sources and exposed above ground surface 9 through seal 37.

OBJECTS

It is an object of the invention to provide an improved long term downhole packer system which avoids deficiencies in the prior art. It is a further object of the system to simply and reliably provide for expansion sealing of downhole packers in groundwater systems with control of expansion 125 pressures and volumes but without complex pressure systems.

It is a further object of the system to provide for testing ports which may be manufactured from standard and widely available parts and then assembled on site for reliable addition to a downhole system reliably at any particular discrete depth.

130 It is a still further object of the system to provide optional means for expansion of the packer seals under careful pressure control with different expansion materials along with choices for removability and/or permanent fixation for use or decommissioning.

It is yet a further object of the invention to provide for simplicity and reliability in 135 increasingly complex modern evaluations with increasing demand for multi-level discrete data collection.

It is yet another object of the invention to maximize sealing effectiveness over long periods while also maximizing the utility of the data and materials pathways within the downhole tools.

140 SUMMARY STATEMENT OF THE INVENTION

The invention provides a downhole groundwater test system including a casing assembly of downhole tubular casing elements comprising thin-walled tubing with an outside diameter and an interior cylindrical cavity, each telescopically joinable end-to-end in serial fluid-tight fashion structured to provide segregated sampling

145 sites within the bore diameter between the ground surface and a lower extremity of the downhole test system including a plurality of casing elements including at least one male telescopic sleeve element formed into an end of the casing element wall from the exterior of the casing element including a sliding male telescopic end section with a outside diameter less than the outside diameter of the casing

150 element, and, an annular abutment formed in the casing element wall from the exterior of the casing between the male sleeve element and the exterior wall of the casing element, and, at least one female telescopic sleeve element formed into an end of an adjacent casing element wall from the interior of the casing element including a sliding female telescopic end section adapted to slide onto a said male

155 sleeve element with an outside diameter less than the outside diameter, and, an annular abutment formed in the casing wall from the interior of the casing between the female sleeve element and the interior of the casing element, and, a pair of opposing annular retainer retention grooves formed into adjacent said male and female sleeve elements from the exterior and the interior of the respective

160 sleeves adapted to overlie each other upon assembly of the male casing element to the female casing element, and, a retention groove access hole in said female sleeve element adjacent said pair of opposing annular retainer retention grooves, and, at least one O-ring groove formed into either or both of the said sleeve elements between said respective annular retainer retention groove and a

165 corresponding abutment each fitted with a sealing O-ring, and at least one sampling casing element including including at least one sampling unit, structured to provide at least one sealing element to close the gap between the casing assembly and the borehole, and at least one blank casing element adapted to act as a downhole spacer between sealing elements and sampling casing elements.

170 The invention also provides:

a retention strap adapted to be removeably inserted into opposing retention grooves through a hole in said female telescopic seal adjacent said retention grooves and bind the sleeves together axially.

a sampling unit secured to said sampling casing wall through a sampling hole in 175 said casing wall to provide controlled fluid flow through from the exterior towards the interior of the casing element, preferably to receive the sampling unit from the interior of the casing element to the exterior of the casing.

an axially elongated radially expansible sealing element, preferably inflatable by a head of water pressure inside the casing assembly adapted to increase its radius 180 and seal the annular space between the sealing element and a borehole wall, and, optionally, to decrease its radial thickness when exposed to either a lower internal pressure or a depletion of the said driver.

for thin-walled tubing as schedule 80 PVC plastic tubing. The invention also provides a downhole groundwater test system wherein the 185 assembly includes at least one annular bore hole alignment ring adapted for fitment upon either the male telescoping sleeve adjacent the abutment or the exterior of a casing element with an outside diameter greater than the diameter of the casing assembly and less than the diameter of the borehole and preferably a diameter greater than the outside diameter of the expansible sleeve.

190 The invention also provides a casing assembly including a plurality of casing elements selected from the group of sampling casing elements, sealing casing elements and blank casing elements adapted to provide depth discrete sampling with a plurality of pairs of male and female telescopic sleeve elements each pair adapted to sealingly mate to each other and to removeably retain their respective

195 sealed and mated connections during assembly and use, preferably with at least one retention strap adapted to be inserted into and occupy the opposing pairs of retention grooves in each mated pair of male and female telescopic sleeves.

The invention further provides a test system as claimed wherein the sampling unit is sealingly secured to the casing element and one of a fixed sampling unit or a 200 flow connecting element including a flow passage from the exterior of the casing assembly to a tubular flow-sampling line connected between the hole and the surface and the hole is a threaded hole tapered to narrow from the interior of the casing pipe element outwards.

The invention also provides a test system including a plurality of tubular sampling 205 lines within the casing assembly each connected between a respective sampling hole and the surface occupying, in the aggregate, occupy no more than 10% or 20% of the fully assembled length of the casing assembly.

The invention further provides a downhole groundwater test system including at least one sampling casing element including at least one sampling hole in a casing 210 side wall and at least one packer casing element including at least a pair of tubular expansible or inflatable bladder members comprising an inner bladder member overlaid by an outer bladder member each sealingly engaged to the exterior of the packer casing element, at least one fluid passage hole between the interior of the packer casing element and the interior of the inner bladder member, structured to provide pressurized sealing between a borehole and the packer casing element by radial enlargement of both bladder members from the casing interior without radial restraint preferably structured to permit free passage of fluid from the ground surface end of the system down through the interior of the casing assembly and through the hole to directly bear upon the inner expansible bladder.

The invention also provides a test system wherein the casing assembly is pressurized between the casing interior and the inner bladder member by one or more of a head of water inside the casing assembly higher than the exterior water table, or, an applied external pressure source and the inner and outer bladder are either in direct surface to surface contact with each other or are separated by a lubrication layer structured to allow differential movement between the bladders upon expansion.

Preferably, the invention provides a test system wherein the inner bladder is directly sealingly engaged to the exterior surface of the packer casing and structured to prevent leakage between the casing interior and the borehole and wherein the direct sealing engagement includes an second annular recess in the packer casing exterior and an external clamping strap structured to engage both the inner bladder and the second annular recess, or, alternatively just the second annual recess.

The invention also provides a downhole groundwater test system wherein the outer bladder is also directly sealingly engaged to the exterior surface of the packer casing and structured to prevent leakage between each of the casing interior, and the inner bladder, and the borehole.

The invention further provides a test system wherein one or more of the casing elements include an annular protective ring structure with a maximum external diameter which is greater than the outer diameter of the casing assembly and less that the nominal diameter of a borehole, and, preferably, greater than the external diameter of the expansible bladders.

The invention also provides a method of testing groundwater at multiple discrete depths in a borehole including constructing a casing assembly at the ground surface adjacent a borehole progressively adding one casing element at a time as the casing assembly is lowered incrementally into the borehole including assembling the plurality of fluid passage lines at the ground surface.

The invention also provides a method of testing including removal of pressurized fluid from the casing assembly, deflating the bladders and reusable removing the casing assembly one element at a time.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 A shows a vertical elevation of a central cross-section of the prior art downhole system of USP'605 taken along the vertical axis of the borehole.

Fig. 1 B shows an expanded view of a portion of the system of Figure 01 A.

Figure 2 shows a vertical section of an alternative proposal for the prior art system of Figure 1 A.

Figure 3 shows a vertical cross-section of the packer seal of the preferred embodiment of the invention.

Figure 4 is vertical cross-section of the packer seal in an alternative preferred embodiment on the system of the invention.

Figure 5 shows an assembly of the tubular components of the system of the preferred embodiment.

Figures 6A and 6B are detailed partial perspective views of the system of the preferred embodiment of Figures 3, 4 and 5 in 2 parts, namely an interconnected sample casing with each of a casing extension and an inflatable packer.

Figure 7 is a partial perspective view of the assembly as capped off for pressurization and use.

Figure 7A is a pictorial view of the preferred embodiment in a fractured rock or mixed downhole use.

Figure 7B is a cross-section showing a pair of sample casings joined together for direct fluids sampling as by L-fitting and line 30 plus an indirect data source 73.

Figures 8Aa and 8B are pictorial views of sampling casing components of the preferred embodiment arranged on site pre-assembly and upon assembly of the 1 ^st section made up just prior to insertion in a bore hole.

Figure 9 shows a pictorial view of the assembly of Figure 8 as 1 ^st inserted in the borehole Fig 9C and during assembly with a 2 ^nd section, Figure 9D.

Figure 10 shows a pictorial view of the assembly of Figures 8 and 9 as capped off once complete.

Figures 1 1 a, 11 b and 1 1c detail assembly and fixation of each casing to the next. Figure 12 shows a partial perspective view of the sample casing.

Figure 13 shows a pictorial semi-axial view down inside the assembly of the preferred embodiment including a wrap-around debris screen.

Figure 14 is a plan view and a cross-section along line C-C of the quilted pad embodiment.

Figures 15a and 15b are cross-sectional axial views of the inside-out threaded coupler connection and groundwater flow and a fixed in place sampling unit.

Figures 16a, 16b, and 16c are detailed side elevations, cross-section and perspective detail views of the preferred embodiment of the sample casing.

Figure 17 is a vertical section of a packer casing element showing alternative embodiments of the casing wall, bladder and protective ring.

DETAILED DESCRIPTION OF THE PRIOR ART PACKER

Figure 1 a depicts a central cross-section of the prior art packer axially aligned as at borehole nominal axis for insertion and removal from nominal borehole 2 along vertical axial directions D-D. The borehole 2 may have any number of actual, but nominal, diameters B-B which may vary from hole to hole, along the length of the hole, and/or along the length of the packer seal and and any of which may be significantly and abruptly non-circular as indicated by directions C-C.

As can be seen in Figure 1 a packer tool radius A-R is a significant portion of borehole radius A-B even under the idealized and standardized conditions of Figure 1 a. An annular body of expansible material 63 is wetted by fluid passing outward through packer wall 60 (as by perforation, not shown) thereby driving the annular body as a whole outward along direction E-E. Notably, packer central cavity 3 is shown constrained as an essentially thin-walled tubular structure as at wall thickness 4. Cavity 3 provides the axial space for 305 measurement samples, data and sealing pressures to transit from downhole to the surface and the reverse. In modern environments these axial spaces are at a high premium as the can carry as few as 1 to many tubular sampling or other data devices, and lines from downhole locations to the surface.

As can be seen in Figure 1 a, lateral space across diameter B-B along directions E-E 310 quickly becomes fully occupied as layers are built up. This build up requires the layers to be as thin as possible so as not to over-occupy the borehole 2. In such configurations, the expansion of material 63 may be restrained by Kevlar™ layer 64, lubricant layer 61 and body portion of outer layer 69 from expanding outward but in achieving such restraint the inner wall 4 is driven in the opposite direction 315 thereby reducing the working diameter/radius A-P and introducing strong bending moments in wall 60 which are particularly concentrated as at thickness variations depicted at 5.

Since the packer length to diameter ratio can be substantial, the bending moment on thin wall 4 increases substantially in amount and speed once the material 320 expansion reaches the borehole wall 2. Such deformations are to be discouraged, especially in long term use situations.

As shown in Figure 1 b thin wall 4 has a nominal outer thickness a-c and is relieved by an amount intended to accommodate the packer by an amount c leaving a supporting wall of thickness b in the critical area.

325 Expansible material 63 as shown in Figure 01 a with nominal thickness b-d also expands at the same rate along non-radial direction F into an unsupported area where both the thin wall 4 bends and rubber sleeves 6 and 7 with thicknesses e and g are at their weakest. In this embodiment the Kevlar™ layer 64 is shown with thickness f. Any forces causing expansion of the radius of the Kevlar™ layer are

330 not accommodated within the surface of that layer but by circumferential movement of the stiff sheet and relative movement between the woven Kevlar™ material 64 with outer layer body 69 by reduced friction layer 61 is encouraged.

Figure 2 show an alternative embodiments described in US'605. In this case the Kevlar™ sleeve 64 is shown as extending beyond the Bentonite™ layer and under the clamp 76. The Bentonite™ itself is shown as axially restrained by a step as at 8 in Figure 2. Thus, upon expansion the packer is divided in to 3 separate zones, F, G and H, representing a sealing zone F, an intermediate zone G and a clamping zone H. It is not disclosed how to practically achieve the 3 zones with the stiff Kevlar™ fabric, particularly in doing so without interrupting long term sealing. Further, in order to achieve the step valuable internal radial space (inside the pacing system) is lost and another point of failure introduced and the overall space requirements increased.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The preferred embodiment of the discrete multi -level downhole system of the preferred embodiment of the invention 10 in Figure 5 includes an assembly of downhole casing elements 10 joined end-to-end in serial fashion and extended, as assembled, into the bore hole 20 as shown schematically in Figures 5 and 6. The assembly 10 includes blank extension casing elements 1 1 extending serially with other casing elements 14 and 1 5 into the bore hole 2 along borehole axis A to the desired depth 22. Each extension casing element 1 1 is modular and is preferably provided pre-manufactured from a plastic such as PVC, in discrete lengths and, preferably, a single external diameter R-R. Extension casing elements 1 1 , preferably of a fixed length, may be joined serially end-to-end to short blank casing joint elements 12, inflatable packer casing elements 13 and/or sampling casing elements 15. The casing elements are assembled one at a time at the surface along with internal components and sampling or pressure tubes and extended into the bore hole 2 along axis A as shown in Figures 8, 9 and 10. Seals (packers) and sampling ports are provided at a variety of discrete depths. The depths are adjustable on or off site to suit individual conditions by the lengths of the assembled components.

Each inflatable packer element 13 includes a double wall inflatable seal 14 of the invention which is adapted to be radially, and preferably uniformly, expanded to completely fill the annular space 21 between the casing assembly 10 and the bore hole wall 20 to provide discrete vertical segregation. The bottom of the casing of the invention 10 is preferably closed with a bottom casing plug 16, attached as at 17, to a suspension cable 18 running from the bottom plug 16 through the interior 22 of the system assembly casings to the surface 9.

As shown in Figures 5b and 5c each of blank casing element 1 1 and inflatable casing element 1 3 would contain, upon assembly, at least one, and preferably a plurality, of individual sampling lines 23, 30 extending from ground plane 9 downhole towards plug 16. As shown in Figure 6 each sampling line 30 is preferably continuous and fast at its lowermost extremity to a corresponding sampling casing 15 and provides a sampling passage 32 from a discrete sampling level 31 through the outer wall of sampling casing element 1 5 along line 30 to a discrete sampling location 23 preferably at and above ground surface 9. Figures 6A and 6B show a vertical section depicting the assembly of a sampling section 1 5, Figure 6B, to an inflatable section 14 from Figure 4 and to a blank section 1 1 , Fig 5, as sections 10, 1 1 , 14, 1 5, and 16 are assembled together along direction 33, all at the surface as in Figs 8 through 1 1 .

Figure 3 shows an axial and vertical cross-section of the preferred sealing stet of the packer casing 1 5 of the system 10 of the invention. Tubular packer element or casing 1 3 is perforated by one or, preferably, a plurality, of holes in its side wall between the ends 300 of the inflatable seal 14 to provide a flow passageway between casing interior 3 and expansion /inflation of the inflatable section 14. Fluid pressure introduced into casing interior 3 drives the inflation fluid (air, water or settable slurry) through hole 32, causing inflatable section 14 to expand outward and in to contact with borehole wall 20 both radially and axially.

Each end 300 of seal 14 is mechanically sealed against casing 1 3 for a fluid-tight connection as at seals 301 and 302 by a pair of circular mechanical strap clamps 303 and 304 each arranged to drive seal 14 into sealing engagement with the outer wall of casing 13 within machined annular grooves 305 and 306 respectively, each of which may be of generally rectangular profile. Each of clamps 303 and 304 are provided with raised edges 307. In an alternative embodiment annular grooves 305 and 306 may have chamferred edges 308. Most preferably strap clamps 303 and 304, grooves 305 and 306 and inflatable sections 14 are dimensioned so that the whole of the clamping seal, as shown in Figure 3, lies within grooves 305 and 306 respectively and within the outer cylindrical boundary R-R of casing 13.

Preferably each end 310 of casing 13 is relieved on the interior as at 311 , or on the exterior, not shown, to provide for tongue and grove, male/female sliding and 400 telescopic connection and disconnection along direction 33 and axially of the casing 13.

Most preferably, seal 14 includes a pair of cylindrical expansible (rubber) bladders 315 and 320. During original assembly of the sealing assembly packer 15 inner bladder 315 is radially expanded and slid axially along casing 13 until its extremity

405 overlaps the 1 ^st sealing ring 306 location as at 321 . Bladder 315 preferably remains in an somewhat extended state so as to remain in intimate contact with the casing outer bounder throughout by reason of tension in the bladder itself. Bladder 320 is similarly radially expanded and slid into place over and in intimate surface to surface contact with inner bladder 315 by reason of tension in the

410 bladder itself. Bladder 320 extends fully over the extremity 321 of the inner bladder and in to groove 305 for sealing compression against the casing 13 by clamp 301 . Further, bladder 320 extends beyond groove 305 for intimate sealing contact with casing 13 outer wall 323 as at 322 in Figure 3.

Figure 4 shows an axial cross-section as in Figure 3 with an alternative embodiment 415 of inflatable section 14. On Figure 4 inner bladder 14A extends fully past groove 306 and fully through groove 305 and beyond for intimate contact with outer bladder 14b throughout.

Preferably, inner bladder 14a and/or outer bladder 14b are coated on their adjacent surfaces with a lubrication and/or releasing agent to prevent inter- 420 bladder binding, friction and/or catchment.

Further alternatively, casing 13 may be fitted with 1 or more enlargement protective rings 401 , 402 above and/or below inflatable seals 14. Rings extend the outer diameter R-R of casing 13 to protect the inflatable seals during movement of the casing 13 during installation and removal. Height 403 of ring 425 401 preferably lies between a single thickness of inner bladder 14a and just over the total thickness of inflatable seal 14, and less than casing to wall dimension 402 when installed, and may be installed before or after installation of the respective bladders to the casing 13. Further alternatively, grooves 305 and 306 may have a lower profile so that clamps 301 may not be fully within respective grooves upon completion of assembly.

In Figure 6a a section of the preferred embodiment of Figure 5 is shown in greater detail in relation to a sample casing 15 and a blank casing element 1 1 having been assembled in to a unit by sliding engagement along direction 33. Hole 32 (Fig 5D, 5E, ref 50) through the casing is interconnected for fluid flow with an L-fitting which is preferably a standard plumbing part threaded in to hole 32 from the inside (Figs 7, 12, 13). Preferably, the L-fitting is axially joined, as by threading or compression fit, at the surface to the plumbing extension 36 for pressure connection to line 30. Most preferably, L-fitting is of sufficient dimensions corresponding to the diameter R-R of the casing 15 and the distance 37 of hole 32 from the proximate end of sample casing 15 that it may be readily threaded into hole 32 and through casing 15 from the inside of casing 15 outwards for a fluid- tight and secure connection. Any exterior excess beyond diameter R-R may be readily machined away.

Similarly, in Figure 6b the sample casing 15 is telescopically slid into engagement with a packer seal 1 .

Each of the fluid-tight joints shown in Figures 5 and 6 include both internal O-ring seal 39 and a retaining clip 40, 52 (Fig 1 1 ). O-ring seal 39 seals between the interior of the casings and the external environment. Preferably, the clip access 40 is external to the seal 39 and includes a pair of internal grooves accessible to a strap 52 (Fig 11 ) as by the access hole opposing grooves on each of the adjoining casings 40 which is inserted circumferentially through the hole 40 to fill the groove and retain the casings in the assembled condition for access insertion downhole, use and removal.

In Figure 7, a perspective view, casing assembly 10 is extended above ground level 9 by insertion of a cap assembly 37 along direction 33. A plurality of lines 30 passes through cap assembly 37 and is connected through end fitting 40 by individual line seals 36 for individual line sampling of fluids delivered to the end fitting 40 sample casing at a time by a corresponding respective and individual line 30. The whole of the casing assembly is an open internal space 22 but for lines

460 30 and may be pressurized with air, water or a settable fluid through pressure fitting 41 by which the source is connected through end fitting 40 directly into internal space 22 which preferably extends to the full length of the operating downhole assembly 10. In Figure 7 A discrete downhole structural lines 70 are shown diagrammatically each of which or each group of which may be the target of

465 discrete groundwater sampling.

Figure 1 1 a shows a partial perspective view of the assembly of a packer casing 14 into a blank casing 12 by axial sliding of the telescoping male/female connections. As shown, packer 14 includes a main body 110 with diameter R-R (Fig 6). The male fitting on packer 14 includes an insert section 1 1 1 having a diameter slidingly

470 acceptable to the inner diameter of blank casing 12 together providing a continuous outer diameter R-R. Insert 11 1 includes an engagement groove 1 12 and a sealing groove 1 14 positioned so as to provide a seal by engagement of O- ring 1 15 with casing 12 internal diameter. Between internal O-ring groove 114 and engagement groove 1 12 a land 1 13 is provided with the same diameter as insert 11

475 to assist in sliding engagement and structural alignment. Preferably O-ring 115 may be inset or partially inset into the sealing groove 114 on either the inner diameter or the male casing or the outer diameter of the female cashing for secure handling and sliding seal, or both.

Detail of the preferred engagement and retention clip strap are shown in Figures 480 1 1 B and 11 C. Insert 1 1 1 of inflatable packer 14 includes the engagement groove 1 12 which is formed in 2 opposing parts, internal 1 12A on the insert 1 1 1 and external 1 12B on the blank casing 12. Access port or hole 34 through blank casing 12 at the location of groove 112 accommodates circumferential insertion of, preferably, a nylon tie strap 52 (Figure 11 C) which fills the groove 1 12 in both parts 485 1 12A and 112B and fixes them together axially until the strap 52 is removed externally. In Figure 7B a paid of sampling casings 15 are joined axially. In each case sampling port 32 penetrates the casing wall at, preferably, a point on the wall with additional thickness as at 72. The upper port in Figure 7B is shown with a data sampling device 73 threaded or glued to port 50 as at 74 across the extra 490 thickness 72. The lower port in Figure 7B shows a detailed cross-section of the sampling-L fitting of the preferred embodiment 75 which is revers threaded from the inside through the wall of casing 15 at the area of increased thickness 72. A plumbing extension 36 may be threaded into L-fitting 75 from the outside assembly once the L-fitting 75 is secured to the casing as shown. Sampling tube 30 is then 495 secured to the extension 36 as by threading, compression fitting or adhesive.

The extra thickness 72 of the preferred embodiment is associated with the open ends of the sampling casing 15 wall being relieved to a smaller inside diameter in the fashion of the female telescoping connection as shown in Fig 1 1 B. With both ends of the casing 15 being relieved to female component, the out diameter of the 500 casing assembly R-R may be maintained structured throughout.

Figures 8A and 8B show pictorial views of the multi -level downhole system of the invention 10 before and during assembly. As at Figure 8A, a plurality of the casing components is laid out on site. As at Figure 8B blank extension casing element 1 1 with end cap 16 is depicted as assembled by telescoping connection to a sampling

505 casing 15 and thence to a inflatable packer 14 and another sampling casing 15 as made ready for the initial lowering of elements of the system 10 into a borehole with wall 20. The assembled casings provide a sampling cavity 31 between the casing diameter R-R and the borehole diameter B-B (Figure 3). Once installed groundwater from sampling in cavity 31 flows in through port or sampling passage

510 32 and vertically upward to the surface by a single sampling tube 30. Each casing preferably includes a pair of retention access points at hole 34 and a pair of sealing O-rings 114 (Fig 1 1 B) to connect and seal the system assembly 10 in a male to female arrangement to prevent leaks between the assembly interior 22 and the ambient groundwater. Most preferably two pairs of O-rings are provided, one pair

515 at each end as known in shadow outline in Fig 1 1 B, as shown. ^"

Necessarily, sampling tubes 30 must be prearranged and pre-cut so that each successive casing may be threaded over the whole of the bundle of tubes 30 as shown in Figures 9A and 9B. In Figure 9A the assembled 1 ^st section of Figure 8B has been lowered in to the mouth of borehole 20 where it is held, preferably with 520 a vice support 163 pending arrival and connection of the next working section. In

Figure 9B an inflatable casing 14 with its packer 14 and a short blank casing 12 have been threaded over the running bundle of tubes 30 and brought in to alignment with the downhole system 10 for sealing engagement and lowering.

In Figure 10 the assembly is shown as fully completed as in direction 33 along axis 525 A (Fig 9) into the borehole 2 from the surface 9.

In Figure 10 the downhole assembly of Figure 9 is complete with a plurality of discrete sampling lines 30 extending up through a blank casing element 10 into sealing engagement with a top cap casing element 37 adapted to bring the overall height of the assembly to a working height above ground level 9 and fully enclose 530 the casing interior volume 22. Sampling lines 30 extend beyond top cap casing 37 and through a header assembly 39 including spacer rings 38 and an upper surface 40. Upper surface 40 includes a plurality of sampling terminations 36 each providing for a discrete sampling points of attachment.

Casing interior 22 is also connected through header body 39 to pressure connection 535 41 by a tube 30 for supply of inflation fluid (air, an expansible fluid or, preferably, water). Inflation pressure is preferably provided by filling the casing interior 22 through connection 41 with fluid to a level above the level of the corresponding water table at the borehole site or beyond as required application of the sealing pressure by a settable fluid results in a permanent installation or a full 540 decommissioning of the downhole once testing is finished.

Figure 12 shows a side elevation in partial perspective of the sampling casing 1 12. In Figure 1 3 the casing of Figure 12 is shown with a preferred outer debris screen 1 30 wrapped around the casing over the location of the sampling port 32 and held in place with a pair of clamping straps 1 31 .

545 As shown at Figure 14 A and B, in an alternative embodiment the settable fluid and pressure inflated packer may be replaced with an expansible and settable solid or semi -solid thin annular body 100 which is wrapped about the casing 101 outboard but inside the inflatable rubber layers 14A, 14B (Fig 3). Water introduced through pressure hole 32 interacts with annular body 100 to case the layer to adsorb

550 and/or interact with the layer 100 material, such as Bentonite™, to cause expansion of the layer. The expansion may be permanent or semi-permanent in that some expansible materials retract once the water source is removed. The annular layer 100 may be formed as in figure 14A with a quilted structure with non-axial threading as at 102 or circumferential threading 103, with or without 555 overlapping quilts. The quilting threading may be box sewn as a 104 in Figure 1 B, or sewn to mid-point as at 105 or sewn to fully segregate the quilts by collapsing the outer surface towards the inner surface by reducing thickness T-T along the sewing lines.

Figures 1 5a and 1 5b show axial cross-sections of preferred sampling ports. In 560 Figure 15a an L-shaped plumbing fitting 1 50 with a tapered plumbing thread 1 51 tapered at angle 1 52 is threaded through casing wall 12 from the inside outward to protrude as at 154. Protrusions 154 may be lathed away or removed by other known means to leave a cylindrical outer casing wall. Once L-shaped coupler 1 50 is fixed, its inside threaded end 1 55 is axial of the casing assembly and readily 565 available for threading on fitting 36 and sampling tube 30. Additional sealing may be alternatively added around the tapered threaded connection 153. Once complete as shown in Figure 1 5a a free flow 1 56 groundwater connection is provided between casing exterior space 21 uphole to the surface for measurement.

In Figure 1 5b an alternative sampling unit 1 59 is shown which may be threaded 570 from the inside out as in Figure 1 5a by a threaded taper 151 or as a straight pipe thread connection 157 which may, alternatively, but not preferably, be non- tapered as at 1 57. From the inside unite 159 is threaded about radial axis as shown at 160 and provides a flow passage through the casing wall 12 along direction 161 . Further alternatively, unit 159 may be added to the outside of the 575 casing 12 in a similar manner, preferably in a machined recess in the wall thickness from the outside inwards. Additional sealing 1 58 may be added between unit 1 59 and casing 12 inside wall 162.

A preferred embodiment of the downhole testing assembly of the invention 10 is shown diagrammatically in Figures 16. Assembly 10, fully assembled, preferably is 580 an elongated cylindrical unitary body as in Figure 5 and is suspended vertically along line 19 from the surface 9 on suspension cable 18 which is secured to an terminal plug 16 as at connection 17. Cable 18 is coaxial (axis A in Figure 16b) with central cable 18 and central to both the assembly 10, its cylindrical inner cavity 3[IN2] , and, preferably, the borehole 2. In Figures 16 the assembly is 585 shown in the context of blank casing elements 12 and without the sampling tubes or connections for ease of reference as each of the telescoping connections along the length of the assembly 10 are preferably the same as shown in Figures 16a and . 16c.

Depending on the configuration of the last or lowest sampling point terminal plug 590 16 may be a solid termination 160 as shown in Figure 61 a or a one allowing water flow between the downhole segregated water layer 160 and the segregated casing interior volume 3 . (16 and 160) In the case of a either termination plug 16 may be secured to the bottom most casing element 162 by threading, welding or by a telescoping connection 165 (Figure 16a) including a male end 166 and a co- 595 operating female end 167.

As shown in Figures 5 and 7-10 the assembly of Figures 16 is brought together at the surface adjacent borehole 2. Casing sections in the desired testing configuration are preferably staged (Figs 7 through 11 ). First, cable 18 is secured to plug 16 and then laid out aligned with successive casing sections. Then one 600 casing at a time is threaded over the bundle of sampling tubes 30, including the cable 18, telescopically joined to the prior casing element and passed seriatim down borehole 2 suspended on cable 18. In many cases, borehole 2 is large enough to accommodate casing outer diameter with an annular space 21 throughout.

Designers must accommodate not only the need for temporary, permanent and/or 605 decommissioning of downhole sampling casings but also the need to keep borehole 2 as small in diameter as possible but still leave room for the inflatable seal, expansible seal or from the surface back filled seal of casing 14, the casing wall thickness 168, the telescoping elements, male 166, female 167 and an interior volume 3 as large in diameter as possible. To the extent possible casing 1 1 outer 610 wall 169 and casing inner wall 170 preferably provide a uniform and smooth cylindrical inner and outer surface throughout.

In the preferred embodiment of Figure 16 the whole of the telescoping connection 165 is provided for within the wall thickness 168 in a robust and mutually supporting manner so that the casings themselves may be simply and conveniently 615 machined from extruded plastic thin-walled pipe, such as PVC or its equivalent.

Thin walls, plastic pipe and robust connections provide for a low-weight downhole assembly which may be made up to a large extent locally to the downhole site with local pipe components and machinery.

Male component 166 of telescoping connection 165 is formed by machining away a 620 portion 170 of the exterior surface of wall 169 from the outside in forming a reduced diameter 175, preferably just less 170a than 1 /2 of wall thickness 168, to form the male sliding surface 176. Next a shallow, preferably rectangular, annular retention groove 177 is formed into the sliding surface 176 to separate the sliding surface 176 into an upstream (in Fig 16) retention land 178 with an axial 625 width 186 and a sealing land 179 with an axial width 187. The male section 176 thus protrudes a distance 188 beyond annular male contact surface 189 plus the chamfer component for a total length 190. Most preferably, the protruding end of male component 166 is chambered as at 180 to provide an insertion guide 181 .

Axial width 185 of annular retention groove 177 is preferably greater that the 630 width of tie strip 52 for ease of entry and removal and so as to permit axial motion between casing elements along the telescoping surfaces.

Female component 167 of connection 165 is formed by machining away a matching portion 200 of the interior surface of wall 170 again just less 170b than 1 1I of wall thickness 168. Next a shallow co-operating female retention groove 201 is 635 machined into the remaining interior wall 202. Groove 201 divides the female sliding surface of 167 into a downstream (Fig 16) retention land 203 and a downstream sealing land 204. Groove 201 is spaced beyond the width 206 of downstream land 203 from female end 205.

Most preferably, retention lands 178 and 203 are the same widths 186,206 and 640 adapted for annular contact between male contact surface 189 and female end 205 once the telescope sliding is complete. This provides that retention grooves 177 and 201 are aligned for insertion of strap 52 through hole 34 into the groove pair in a circumferential manner. Width 185 of the grooves 177 and 201 is greater than the width of the strap 52 for ready insertion and optional ready removal while 645 securing the casing sections in position for use.

Most preferably, female sealing land 204 is machined away from the inside and internally from the retention groove 201 to provide for an annular pair of O-ring grooves 207, into which O-ring seals 208 are inserted and lubricated in place.

Most preferably, female telescoping section 167 has a depth 21 1 which may include 650 a chamfered end 21 1 and retention land depth 206 plus sealing land 209 for a total depth preferably greater than or equal to the male length 190. In action, it is preferred that assembly of each casing to the next causes annular contact preferably between male end 181 with female chamfer 211 and between contact 189 and female end 205.

655 In Figure 16a elements 170A and 170B are the dimensions of the male and female machined away portions of the casing wall. Chamber 180 is provided a the distal ends of the male and female sleeves to enhance assembly. Dimension 210 is the axial dimension between the retention groove and the depth of the female sleeve, namely 209 minus 206. Mating sleeve ends are 181 for the male sleeve

660 end and 161 for the remand end and the internal radius of the casing is 191 .

Thus, weakness in the wall thickness 168 of the casing elements 11 is shared over the broad land surfaces and the annular contact surface or surfaces. Most preferably, female connection depth 208 is greater than male length 190 so that full penetration results in a single annular contact on surface 189. This provides 665 for a small but valuable vertical motion in the up/down direction which is useful in installation and removal as neither the casing assembly 10 nor the borehole 2 are or remain perfectly cylindrical during the lifetime of the downhole assembly.

Alternatively, a small difference in the diameter of the male section 175 and the female section 212 will provide for a permissible off-axis and variable angular 670 displacement between sections while maintaining the O-ring seals and assembly integrity.

In Figure 17 is shown alternative arrangements of the inner and outer bladders 14a and 14b, the engagement grooves 305,306, casing outer bladder surface 173and the sealing clamps 170 with reduced and full casing diameter alternatives as shown at W, X, Y and Z. Protective ring 401 extending into space 400 may be mechanically slid in place over the outer casing wall as at 402, alternatively, threaded on 163 from the male sleeve abutment. Further alternatively, protective ring may have an internal diameter which matches the diameter of the male sleeve and may be slide onto the male sleeve before installation of the O-ring seals for capture between the male end and the female end.

While the preferred embodiment has been set forth above, those skilled in the art will appreciate the the scope of the invention is significantly broader and as outlined in the claims which appear below.

List of Elements

1 prior art packer

2 borehole

3 central cavity/ casing interior

4 wall thickness/ inner wall/ thin wall

5 thickness variations depicted

6 rubber sleeve

7 rubber sleeve

8 location

9 ground/surface

10 casing assembly of the invention

1 1 casing elements

12 joint elements/blank casing

13 inflatable packer casing elements

14 inflatable seal/drive seal

14B bladder

15 sampling section

16 bottom casing plug

17 connection

18 suspension cable 19 line

20 borehole wall/ borehole

21 annular space

22 depth/interior/space

23 sampling location / sampling lines

30 sampling lines / sampling tube

31 sampling level

32 sampling passage / hole

33 direction

34 hole

35 sealing rings

36 plumbing extension

37 distance/ casing element/ cap assembly

38 spacer rings

39 O-ring seal / header body

40 clip / upper surface / end fitting

41 pressure connection

41 A bladder

50 sampling port

52 tie strip

60 packer wall

61 lubricant layer

62 inside wall

63 material

64 sleeve

69 outer layer

70 structural lines

72 additional thickness at

73 sampling device

74 location

75 preferred embodiment / L-fitting

76 clamp 100 annular body

101 casing

102 location

103 circumferential threading

104 location

105 location

1 10 annular body

1 1 1 inner section

1 12 groove

1 12A internal

1 12B external

1 13 land

1 14 groove

1 1 5 O-ring

140 layer

141 threading as at

142 circumferential threading

143 box sewn as a

144 mid-point as at

160 solid termination

162 bottom most casing element

165 telescoping connections

166 male end

167 female end

168 wall thickness

169 out wall

170 inner wall

170A, 170B male/female machined away dimensions

175 reduced diameter

176 sliding surface

177 retention groove

178 Retention Land 179 sealing land

185 axial width

186 with

187 axial width

188 distance

189 male contact surface

190 chamfer component for a total length

200 matching portion

201 retention groove

202 interior wall

203 retention land/ downstream land

204 sealing land

205 female end

206 width / land depth

207 O-ring grooves

208 O-ring seals

209 sealing land

211 depth / chamfered edge

212 female section

300 ends

301 seal/ lamp

302 seal

303 and 304 strap clamps

305 and 306 annular grooves

306 ring

307 raised edges

308 chamfered edges 3

310 end

311 interior as at

315 bladder

321 location as at /extremity 321

320 Bladder location outer wall space

enlargement rings height

height