CA2502800A1 - Enhancement of flow rates through porous media - Google Patents
Enhancement of flow rates through porous media Download PDFInfo
- Publication number
- CA2502800A1 CA2502800A1 CA 2502800 CA2502800A CA2502800A1 CA 2502800 A1 CA2502800 A1 CA 2502800A1 CA 2502800 CA2502800 CA 2502800 CA 2502800 A CA2502800 A CA 2502800A CA 2502800 A1 CA2502800 A1 CA 2502800A1
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- Prior art keywords
- drive
- liquid
- ground
- chamber
- packer
- Prior art date
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Links
- 239000007788 liquid Substances 0.000 claims abstract description 55
- 239000000463 material Substances 0.000 claims abstract description 28
- 125000004122 cyclic group Chemical group 0.000 claims abstract description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 8
- 229910000278 bentonite Inorganic materials 0.000 claims description 6
- 239000000440 bentonite Substances 0.000 claims description 6
- SVPXDRXYRYOSEX-UHFFFAOYSA-N bentoquatam Chemical compound O.O=[Si]=O.O=[Al]O[Al]=O SVPXDRXYRYOSEX-UHFFFAOYSA-N 0.000 claims description 6
- 238000004891 communication Methods 0.000 claims description 3
- 230000035699 permeability Effects 0.000 claims description 3
- 238000005067 remediation Methods 0.000 claims description 3
- 229920006395 saturated elastomer Polymers 0.000 claims description 2
- 239000012530 fluid Substances 0.000 claims 1
- 230000001681 protective effect Effects 0.000 claims 1
- 239000002689 soil Substances 0.000 abstract description 10
- 238000002347 injection Methods 0.000 abstract description 2
- 239000007924 injection Substances 0.000 abstract description 2
- 230000002265 prevention Effects 0.000 abstract 1
- 230000015572 biosynthetic process Effects 0.000 description 3
- 230000001427 coherent effect Effects 0.000 description 3
- 230000035515 penetration Effects 0.000 description 3
- 230000009471 action Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 244000118350 Andrographis paniculata Species 0.000 description 1
- 101150007144 Intu gene Proteins 0.000 description 1
- 101100317378 Mus musculus Wnt3 gene Proteins 0.000 description 1
- 235000014328 Schoenoplectus acutus var occidentalis Nutrition 0.000 description 1
- 244000136421 Scirpus acutus Species 0.000 description 1
- 235000014326 Scirpus californicus Nutrition 0.000 description 1
- 235000017913 Scirpus lacustris Nutrition 0.000 description 1
- 241000282887 Suidae Species 0.000 description 1
- 241000534944 Thia Species 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 210000000941 bile Anatomy 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000000977 initiatory effect Effects 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 230000007480 spreading Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/25—Methods for stimulating production
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09C—RECLAMATION OF CONTAMINATED SOIL
- B09C1/00—Reclamation of contaminated soil
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B33/00—Sealing or packing boreholes or wells
- E21B33/10—Sealing or packing boreholes or wells in the borehole
- E21B33/12—Packers; Plugs
- E21B33/127—Packers; Plugs with inflatable sleeve
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Geology (AREA)
- Mining & Mineral Resources (AREA)
- Environmental & Geological Engineering (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Soil Sciences (AREA)
- Consolidation Of Soil By Introduction Of Solidifying Substances Into Soil (AREA)
Abstract
Especially in loose soils, driving a drive-point apparatus into the ground can create a leakage path in which liquid injected out into the ground tends not to spread laterally but to squirt upwards towards the surface; a packer is provided, to seal between the tube of the drive-point apparatus and the ground material. The prevention of such leakage is especially important when the injection is being done by cyclic pulsing, especially by out-and-back surge-pulsing.
Description
Title: ENHANCEMENT OF FLOW RATES THROUGH POROUS MEDIA
(001J 'This invention xelates to inject:iocs t: yiquid from a bclrehole into the suria:~undinc~ ground mat_f~~,. ' . "':i ;~ may be done, when, for example, it is desired to inject and distribute,a remediation ~tibstance n+.o ~. c.ontaminnt-ec? ac;v,i far, ~he invention addresBea the special problem; that can .:c.r:_se ~.«fi~:;. 'hF- borehc~la is made by a drive-pUirit apparatus.
(001J 'This invention xelates to inject:iocs t: yiquid from a bclrehole into the suria:~undinc~ ground mat_f~~,. ' . "':i ;~ may be done, when, for example, it is desired to inject and distribute,a remediation ~tibstance n+.o ~. c.ontaminnt-ec? ac;v,i far, ~he invention addresBea the special problem; that can .:c.r:_se ~.«fi~:;. 'hF- borehc~la is made by a drive-pUirit apparatus.
[002] The present invention is a development of the technology as described in CA-2,232,948, to which attention is hereby direGtCd.
GENERAL FEATURES OF THE INVENTION
GENERAL FEATURES OF THE INVENTION
[003] zn the apparatus for adding a liquid into porous ground material, o! the invention, the prl:f~rtred features area - the apparatus includes a drive-point structure, which is capable of being driven, from the surface, into the ground;
- the drive-point stx'ucture include$ a tube, comprising a tube wall, which definett ari interior chamber;
- the apparatus includes a source of a liquid, the source being located at the surface, and includes a ~nearis for transferring the liquid therefrom into the chamber;
- the tube wall .includes an exit port, through which the chamber is in liquid transfer coemiunication with the ground material outside the apparatus;
- the apparatus includes an expandable packer, and a mean9 far expanding same;
- the packer is of annular configuration, and is located radially outside the tube wall, between the tube wall and the ground matu>rial;
- the packer is located above the level of the exit port;
- the packer is effective, when expanded, to exert pressure inwards against the tube wall and outwards agaxn~t the gzound material; and - the structure and arrangement of the packer, when =nflated, is such as to provide a seal between the tube wall and the grpund material, thexeby tQ inh.ibi.t the passage of 7.it~~z:~<: ul::w,xrds towards tim surfc~ee from the exi ~ poZt, outside the 'ru:u~--~,:-..~ _ DET~.ILED DESCRIPTI02r 0; f.W:PERRED EMBODIi~IEl\1W
r004~ By way of further explanation of the invention, exemplary embodiment9 of the inweatiori will riow be described with reference to the accompanying drawings, in which:
Fig 1 ig a sectioned side view of an apparatus for injecting ~.iquid into the ground, including a first drive-point apparatus.
Fig 2 is a sectioned side view of an apparatus for injecting liquid inta the gx~our~d, including a second drive-point apparatus.
Fig 3 is a sectioned side view of az~ apparatus for injecting liguid into the ground, including a third drive-point apparatus.
Fig 4 is a sectioned side view of a first above-ground portion of an apparatus for injecting liquid into the ground.
Fig 5 is a sectioned side view of a second above-ground portion of an apparatus for injecting liquid into the ground.
Fi,g 6 is a sectioned side view of a third above-ground portion of an apparatus for injecting liquid into the ground.
Fig 7 is a diagrammatic view of some of the above.-ground components of ari apparatus for injecting liquid into the ground.
[005) the apparatuses shown in the accompanying drawings and described below are examples which embody the invention. It should be rioted that the scope of the invention is defined by the accompanying claims, and not necessarily by specific featuxes of exemplary embodiments.
[006 Diameter is at a premium in borehole engineering. Where the job ca~1 be done with sma~.ler-sized boreholes, smaller size is preferred. In the smaller siMes of bprehole (i.e less than. about ten cm diameter, and preferably less than five cm) drive-point technology is favoured. In the slim drive-point apparatuses, it is riot practical to provide dOwn~-hole pistons, cylinaezs, powez z-CtuFll:Grs, vdl4'2S, d1W i ~~1t3 ll~iC:, dCIG~ g0 2111, Or 1ttf»i', ref thf' machinery and mechanism has to be provided at the surface.
~ U~;~ ;; 1 F ~_tJ 1 so:~,=.v:? :a:~ apya~:3lu~ for ef feting a Snmii-d~.urneter barehole, having a d~'ive-point configuration. Here, the apparatus is driven down int4 the ground, either by simple pressing or by the use of a hamaaer, rather than by rotary drilling. (The manner of driving the apparatus into the ground is conventional, and is not described herein.) Drive-point devices are especially suitable for use in ground materials (soils) of an easily-penetrable nature, sash as grovels or tills, and are suitable for use at depths of e.g ten metres, and rarely more than thirty metres.
[008] the apparatus 21 in Fig 1 includes a drive-head 23, and a tube 25. The wall of the tube 25 defines an inta~rior chamber 27, which extends to the surface. An exit port, comprising several through-holes 29, communicated the chamber 27 with the ground material 30 outside the tube.
[009] At tk~e surface, injecting and pulsing machinery 32 is provided. various arrangements can ba used for effecting pulsing, of which three are illustrated (diagrammatically) in Figs 4,5,6.
Other aspeGta of the machinery are shaven in block diagram form iri Fig 7, [0010] A packer 34 is incorporated ~.x~to the apparatus 21.
During driving, the packer 34 is uninflated, and resides in a recess 3fi in the wall pf the tube 25. When the apparatus has been driven to its desired working depth, as shown, now the packer 34 is inflated.
[0011] One manner of inflating the packer 34 is for the packer to include a mass of e.g bentonite, which swells upon contact with water. The bentonite may k>e arranged to Fee in contact with a hole in the tube 25, whereby, when water enters the chamber 27, the water contacts the bentoni_tc~., and causes if; to swell. Alternatively, it <,an be arranged that wa'.:~~r Nreaen;: in tile surromdanc~ ground material contacts the hr~ntonite, and causes it to swell. Of course, the designer sh.ouJd ~F~.~ tn i t ;:llat thr.: swel.lin~ of the baritonil_,~
i~~
ciE~l.ayed to t:ht cxt~nt t',~,.~.t. :m s~.yuii:ic:aca~ ~welliny oCCUrs actually duric~g dr,ivind.
[0012] Generally, .it is not possible later to remove a bentonite packer. Similarly, a packer made of concrete generally cannot be xemoved. If it ix desired to deflate the packer, the packer can be made as~an i,~iflatable bag, and a pigs oonnects the bag to the surface, and the inflation/deflation ie effected and contxolled from the surface, in the manner well-known to designers of down-hole packers.
[0013] The drive-point apparatuses are used g~nerally ire the looser, shallower, ground materials. Although these soils are horizontallx stratili~d, and oan be resistant to vertical movement of the liquid, it eomltimes happens that this action of driving the drive-point device into the ground cnn create what almost amaunts~ to an open conduit, around the device, caused by disturbing the ground.
In that case, when the liquid is injected from the exit port, the liguid tends simply t4 leak upwards, by sguirting bank up to the surface, around the outside of the device, up the said annular conduit created by the loosened soil material.
[0014] If that happens, the deriired lateral (radial) spreading of the injected liquid, over a large radial area, Can be significantly spoiled. It is recognised that this tendency for the injected liquid to squirt upwards may be alleviated by providing the packer 25 around they drive-point device, just above the exit port 29 that provides liquid.-transfer communication between the tube 25 and the ground formation. The presence of the packer iias been found very effective in ensuring the injected liquid spreads laterally intp the formation, rather than upwards towards the surface.
~?O LS J Fig 2 shows a d i 2 fereni: k =nc3 of drive-pc;~.nt apparatus, which includes an inner tube 41 arid an outer tube 43. The inner tube 41 is fixed to the d:-.i.ve-point '~3, ;,bile :ue ou;:er tube 43 can a 1_; <~a axzally relat.i~,~:. '~e: t.:ie iuiler Lute :~y . 'iiw outer-tutee engages a driving shoulder 45 on the drive-point 23 during driving, but when the drive-point has reached its working depth the outer tube 43 is withdrawn upwards, which exposes a bottom portion of the inner tube 41. This bottom portion is perforated, at 29, to form an exit port from the interior chamber 27, whereby liquid asn be inj*cted from inside the inner tube 42 cut ,into the surrounding ground material.
[0016] Packex 47 prevents the injected liquid fxom passiag upwards, i.e frbrn passing upwards between the inner and outer tubes, and from passing upwards around th* outside of the outex tube 43.
The packer 47 is inflated after the outer-tube 43 has been withdrawn upwards. The packer 47 may be of bentonite which is inflated by contact with water, or the packex may be inflated by a pipe from the surface.
X0017] As shown in Fig 3, in some oases the ground strata include a layer 50 of loose soil near the surface, with a layex 52 of denser soil below. Now, it may be simple to provide a large-diameter hole 54 in the loose soil, while the narrower drive-pofnt hole 56 is made is the denser materia,I underneath. It can be effective to place the packer 58 in the looser ground, i.e in the larger diameter portion 54 of the borehole.
[9018] Where the packer is located around the outer tube 43, a seal 6D should be provided between the inner tube 41 and the cuter tube.
[OQ19] In Fig 3, an inflation/deflation pipe iii c:onnects the packer 58 to the surface. Alternatively, in plarcv of the inflatable pac~l_er 5c3, the loose or open space around the appaca~.us may be _ ~l.led ;~t.i_th concrete, bentonite, etc. In thal_ w:~ra~, .-:gain, the intention would be that the apparatus remain in tho borehole ~ermanPntly.
[002U) As discussed in the above mentioned CA-2,232,948, lateral penetration into the surrounding ground of an injected liquid is hugely enhanced by the praceduxe of slosh- or surge-pulsing. Here, a coherent body of liquid outside the borehole is caused to slosh or surge back and forth by alternately injecting l~.quid from the borehale and then sucking it back into the borehole. When thia~ out-and-back pulsing is repeated, cyclically, over a prolonged period of time, the coherent body may be found to extend many tens of metres laterally from the borehole. Furthermore, the portion of the aquiFer in contact with the coherent aurg~.ng body of water gradually becomes homogenised. and its porosity and permeability are improved.
Even when the injection is pulsed, but without the reversal of flow that characteri$es serge-pulsing, the improvement in lateral penetration distance can be very worthwhile, as compared with just a steady application of a pressure head. The enhanced lateral penetration arising fxom pulsing is especially vulnerable to being spoiled by the escape of injected liquid upwards around the drive point apparatus. Therefore, it is eapeoially impo7rtant to includA
the packer when pulsing is being done.
[0021] Ir~jectiag a remediation substance, whether dissolved or suspended iri water, ox its~3lf a liquid, evenly and thoroughly dyer the whole area around the borehole, is one of the desired effects of surge-pulsing. That effect would be spoiled by the upwards leakage, and i.t is such upwards leakage that i~t prevented by the presence of the packer, as described.
[0022] In Fig 4, a piston 65 floats up/down in a cylinder 67.
Compressed air is supplied via a valve 69, which dri~~es the piston fi5 dow:o and forces liquid frcun inside the inner tuLe; 4? out into the ground formation. For the return stroke, the valve b9 .is simply exhausted. Now, the porosity of the ground formaLica~~ L~ci.ng oz a resilient nature, lic~u.i.cl wi. ~1 .Eiow back intU the inr.c'.- t.u!~<: ~1_, through ~.he perforations 29, due to that resiliet:ce. Make-up liquid is added, t=o suit, througt: supply port 70, Which ~.'.. (-'ec' From a su ~i ,u'l,' E> re~~e: r~vc~ii .
[0023] Whether the injected liquid will flow back into the borehole when the driving pressure is released depends on the porous elasticity of the ground. Often, ground material (especially at shallow depths) is quite resilient in this *en**, whtxeby a return flow of liquid back into the borehole happens when the piston is released, even if the piston is net mechanically drawn back.
[0024] operating a pulse-generating piston can be useful in homogenising the ground around the borehole, even if the licjuid does not xeturn on the piston upatrokQ_ For example, a steady positive pressure may be maintained at the l~.c~uid supply from the reservoir, whereby the pulsing action do#s create cyclic variations in flowrate, but doeb not cau*e the flow to actually reverse during the upstroke. Especially when tk~e ground is barely saturated, this pulsing-without-reversing, though loot a* highly effective aft pulsing-with-reversing, still can be effective to fill the interstitial pores and spaces more completely than simply injecting the liquid under pressure, and can be effective to advance the saturation more as a flat franc than as a fingered fiont.
{0025] Also, even if the situation is such that the favoured surge- or slosh-pulsing (i.e pulsing-with-reversing] can be achieved eventually, it might be necessary first to go through a pulsing-without-reversing staga_ Then, gradually, as coherence of the injected body of liquid is procured, pulsing-with-reversing takes over, leading to the great increases in saturation capacity, and improved homogeneity, of the ground.
[0026] Tf there is to be any chance o~ flow reversal during the upstroke, of course the (pr~assur.i red) su~aply of make.-up liquid should be interrugl~ed du: ~y; t;.,e upstroke, using the valve 70.
j0027) Especial l;~ .-it yr:ee.:~~.or depths, ~aften the.rc: i.:; not ::rough porosity resilience, and l.ha pit;ton must be mechanically drawn back on the return stroke. Thifi can be done using Compressed air, from the surface, as shown in Fig 5. Apart from the forced withdrawal of the piston, the Fig 5 apparatus operates similarly to the Fig 4 apparatus.
(0028] gig 6 shows a set-up in which pulse* are created without the use of a mechanical piston. Here, air pressure is built up in an air chamber 74. When the valve 76 is opened, this pressure is dumped into the inner-tube 41, which causes the liquid in the inner-tube to pass out into the surrounding ground through the exit port.
At the end of the expulsion, the excess air pressure in the inner-tube is released at the valve 7B, and a fresh charge of tttaka-up liquid is admitted through the valve 7D. Liquid depth sensors, pressure sensors, etc, may be prov~,ded and used for timing the sequence of valve openings And closings, as reguired. Some of these items are shown in Fig 7.
(0029 The described ways of initiating the movements of liquids should not be regarded as exhaustive, and other effective ways of creat~.ng the pulses are within the competence of skilled designers of down-hole machinery. For example, a piston can be driven by means c~f an electric actuator, which has the benefit of being highly aOntrollable as to speed, acceleration, stooping points, etc.
[0030 The problems addressed by the apparatus as described herein arise mainly in the looser ground materials. The tighter (less permeable) ground materials tend to close tightly against the wall of the tube of the drive-point apparatus. and the tendency of liquid to leak upwards, around the tube, is minimal in tight soils.
Alan, the loose soils, in which the nroble~; occurs, tend to be near the surface, i.e: at shallcoa depth, which is the area of preference fGr usage of the drive-poi~it type of apparatus.
[003t] Thus, the invention preferably .is used when the p~.rmeability, or hydraulic conduct.ivi.ty, of tk~e ground is looser than about 0.7. cm/sec. The hydraulic conductivity of the ground is measured as the velocity of the liquid, in cm/sec, through the ground, per unit of imposed pressure gradient. The imposed pressure gradient is dctuahy dimansionlesa, in that it .is measured as a dxop of so many 0110. of pressure head, per cm of length along the direction of the velocity. A permeability of 0.1 cm/sec is aS9ociated with fine silt or till. The clays, gsneraliy, are so tight that no steps need be taken to prevent upwards leakage. The invention is xuitable for use with very loose soils, such as laxqe-gra~,ned gravels.
(0032] The packer itself takes up some annular space even when uninflated, and the uninflated packer should not be the radially-outex>aost component pf the drive-paint structure, or ~.t might be damaged by contact with the ground material as the structure is driven dowritaards into the ground. Thus, preferably, the drive-head 23 is of a greater diameter than the overall diameter of the uninflated packer.
- the drive-point stx'ucture include$ a tube, comprising a tube wall, which definett ari interior chamber;
- the apparatus includes a source of a liquid, the source being located at the surface, and includes a ~nearis for transferring the liquid therefrom into the chamber;
- the tube wall .includes an exit port, through which the chamber is in liquid transfer coemiunication with the ground material outside the apparatus;
- the apparatus includes an expandable packer, and a mean9 far expanding same;
- the packer is of annular configuration, and is located radially outside the tube wall, between the tube wall and the ground matu>rial;
- the packer is located above the level of the exit port;
- the packer is effective, when expanded, to exert pressure inwards against the tube wall and outwards agaxn~t the gzound material; and - the structure and arrangement of the packer, when =nflated, is such as to provide a seal between the tube wall and the grpund material, thexeby tQ inh.ibi.t the passage of 7.it~~z:~<: ul::w,xrds towards tim surfc~ee from the exi ~ poZt, outside the 'ru:u~--~,:-..~ _ DET~.ILED DESCRIPTI02r 0; f.W:PERRED EMBODIi~IEl\1W
r004~ By way of further explanation of the invention, exemplary embodiment9 of the inweatiori will riow be described with reference to the accompanying drawings, in which:
Fig 1 ig a sectioned side view of an apparatus for injecting ~.iquid into the ground, including a first drive-point apparatus.
Fig 2 is a sectioned side view of an apparatus for injecting liquid inta the gx~our~d, including a second drive-point apparatus.
Fig 3 is a sectioned side view of az~ apparatus for injecting liguid into the ground, including a third drive-point apparatus.
Fig 4 is a sectioned side view of a first above-ground portion of an apparatus for injecting liquid into the ground.
Fig 5 is a sectioned side view of a second above-ground portion of an apparatus for injecting liquid into the ground.
Fi,g 6 is a sectioned side view of a third above-ground portion of an apparatus for injecting liquid into the ground.
Fig 7 is a diagrammatic view of some of the above.-ground components of ari apparatus for injecting liquid into the ground.
[005) the apparatuses shown in the accompanying drawings and described below are examples which embody the invention. It should be rioted that the scope of the invention is defined by the accompanying claims, and not necessarily by specific featuxes of exemplary embodiments.
[006 Diameter is at a premium in borehole engineering. Where the job ca~1 be done with sma~.ler-sized boreholes, smaller size is preferred. In the smaller siMes of bprehole (i.e less than. about ten cm diameter, and preferably less than five cm) drive-point technology is favoured. In the slim drive-point apparatuses, it is riot practical to provide dOwn~-hole pistons, cylinaezs, powez z-CtuFll:Grs, vdl4'2S, d1W i ~~1t3 ll~iC:, dCIG~ g0 2111, Or 1ttf»i', ref thf' machinery and mechanism has to be provided at the surface.
~ U~;~ ;; 1 F ~_tJ 1 so:~,=.v:? :a:~ apya~:3lu~ for ef feting a Snmii-d~.urneter barehole, having a d~'ive-point configuration. Here, the apparatus is driven down int4 the ground, either by simple pressing or by the use of a hamaaer, rather than by rotary drilling. (The manner of driving the apparatus into the ground is conventional, and is not described herein.) Drive-point devices are especially suitable for use in ground materials (soils) of an easily-penetrable nature, sash as grovels or tills, and are suitable for use at depths of e.g ten metres, and rarely more than thirty metres.
[008] the apparatus 21 in Fig 1 includes a drive-head 23, and a tube 25. The wall of the tube 25 defines an inta~rior chamber 27, which extends to the surface. An exit port, comprising several through-holes 29, communicated the chamber 27 with the ground material 30 outside the tube.
[009] At tk~e surface, injecting and pulsing machinery 32 is provided. various arrangements can ba used for effecting pulsing, of which three are illustrated (diagrammatically) in Figs 4,5,6.
Other aspeGta of the machinery are shaven in block diagram form iri Fig 7, [0010] A packer 34 is incorporated ~.x~to the apparatus 21.
During driving, the packer 34 is uninflated, and resides in a recess 3fi in the wall pf the tube 25. When the apparatus has been driven to its desired working depth, as shown, now the packer 34 is inflated.
[0011] One manner of inflating the packer 34 is for the packer to include a mass of e.g bentonite, which swells upon contact with water. The bentonite may k>e arranged to Fee in contact with a hole in the tube 25, whereby, when water enters the chamber 27, the water contacts the bentoni_tc~., and causes if; to swell. Alternatively, it <,an be arranged that wa'.:~~r Nreaen;: in tile surromdanc~ ground material contacts the hr~ntonite, and causes it to swell. Of course, the designer sh.ouJd ~F~.~ tn i t ;:llat thr.: swel.lin~ of the baritonil_,~
i~~
ciE~l.ayed to t:ht cxt~nt t',~,.~.t. :m s~.yuii:ic:aca~ ~welliny oCCUrs actually duric~g dr,ivind.
[0012] Generally, .it is not possible later to remove a bentonite packer. Similarly, a packer made of concrete generally cannot be xemoved. If it ix desired to deflate the packer, the packer can be made as~an i,~iflatable bag, and a pigs oonnects the bag to the surface, and the inflation/deflation ie effected and contxolled from the surface, in the manner well-known to designers of down-hole packers.
[0013] The drive-point apparatuses are used g~nerally ire the looser, shallower, ground materials. Although these soils are horizontallx stratili~d, and oan be resistant to vertical movement of the liquid, it eomltimes happens that this action of driving the drive-point device into the ground cnn create what almost amaunts~ to an open conduit, around the device, caused by disturbing the ground.
In that case, when the liquid is injected from the exit port, the liguid tends simply t4 leak upwards, by sguirting bank up to the surface, around the outside of the device, up the said annular conduit created by the loosened soil material.
[0014] If that happens, the deriired lateral (radial) spreading of the injected liquid, over a large radial area, Can be significantly spoiled. It is recognised that this tendency for the injected liquid to squirt upwards may be alleviated by providing the packer 25 around they drive-point device, just above the exit port 29 that provides liquid.-transfer communication between the tube 25 and the ground formation. The presence of the packer iias been found very effective in ensuring the injected liquid spreads laterally intp the formation, rather than upwards towards the surface.
~?O LS J Fig 2 shows a d i 2 fereni: k =nc3 of drive-pc;~.nt apparatus, which includes an inner tube 41 arid an outer tube 43. The inner tube 41 is fixed to the d:-.i.ve-point '~3, ;,bile :ue ou;:er tube 43 can a 1_; <~a axzally relat.i~,~:. '~e: t.:ie iuiler Lute :~y . 'iiw outer-tutee engages a driving shoulder 45 on the drive-point 23 during driving, but when the drive-point has reached its working depth the outer tube 43 is withdrawn upwards, which exposes a bottom portion of the inner tube 41. This bottom portion is perforated, at 29, to form an exit port from the interior chamber 27, whereby liquid asn be inj*cted from inside the inner tube 42 cut ,into the surrounding ground material.
[0016] Packex 47 prevents the injected liquid fxom passiag upwards, i.e frbrn passing upwards between the inner and outer tubes, and from passing upwards around th* outside of the outex tube 43.
The packer 47 is inflated after the outer-tube 43 has been withdrawn upwards. The packer 47 may be of bentonite which is inflated by contact with water, or the packex may be inflated by a pipe from the surface.
X0017] As shown in Fig 3, in some oases the ground strata include a layer 50 of loose soil near the surface, with a layex 52 of denser soil below. Now, it may be simple to provide a large-diameter hole 54 in the loose soil, while the narrower drive-pofnt hole 56 is made is the denser materia,I underneath. It can be effective to place the packer 58 in the looser ground, i.e in the larger diameter portion 54 of the borehole.
[9018] Where the packer is located around the outer tube 43, a seal 6D should be provided between the inner tube 41 and the cuter tube.
[OQ19] In Fig 3, an inflation/deflation pipe iii c:onnects the packer 58 to the surface. Alternatively, in plarcv of the inflatable pac~l_er 5c3, the loose or open space around the appaca~.us may be _ ~l.led ;~t.i_th concrete, bentonite, etc. In thal_ w:~ra~, .-:gain, the intention would be that the apparatus remain in tho borehole ~ermanPntly.
[002U) As discussed in the above mentioned CA-2,232,948, lateral penetration into the surrounding ground of an injected liquid is hugely enhanced by the praceduxe of slosh- or surge-pulsing. Here, a coherent body of liquid outside the borehole is caused to slosh or surge back and forth by alternately injecting l~.quid from the borehale and then sucking it back into the borehole. When thia~ out-and-back pulsing is repeated, cyclically, over a prolonged period of time, the coherent body may be found to extend many tens of metres laterally from the borehole. Furthermore, the portion of the aquiFer in contact with the coherent aurg~.ng body of water gradually becomes homogenised. and its porosity and permeability are improved.
Even when the injection is pulsed, but without the reversal of flow that characteri$es serge-pulsing, the improvement in lateral penetration distance can be very worthwhile, as compared with just a steady application of a pressure head. The enhanced lateral penetration arising fxom pulsing is especially vulnerable to being spoiled by the escape of injected liquid upwards around the drive point apparatus. Therefore, it is eapeoially impo7rtant to includA
the packer when pulsing is being done.
[0021] Ir~jectiag a remediation substance, whether dissolved or suspended iri water, ox its~3lf a liquid, evenly and thoroughly dyer the whole area around the borehole, is one of the desired effects of surge-pulsing. That effect would be spoiled by the upwards leakage, and i.t is such upwards leakage that i~t prevented by the presence of the packer, as described.
[0022] In Fig 4, a piston 65 floats up/down in a cylinder 67.
Compressed air is supplied via a valve 69, which dri~~es the piston fi5 dow:o and forces liquid frcun inside the inner tuLe; 4? out into the ground formation. For the return stroke, the valve b9 .is simply exhausted. Now, the porosity of the ground formaLica~~ L~ci.ng oz a resilient nature, lic~u.i.cl wi. ~1 .Eiow back intU the inr.c'.- t.u!~<: ~1_, through ~.he perforations 29, due to that resiliet:ce. Make-up liquid is added, t=o suit, througt: supply port 70, Which ~.'.. (-'ec' From a su ~i ,u'l,' E> re~~e: r~vc~ii .
[0023] Whether the injected liquid will flow back into the borehole when the driving pressure is released depends on the porous elasticity of the ground. Often, ground material (especially at shallow depths) is quite resilient in this *en**, whtxeby a return flow of liquid back into the borehole happens when the piston is released, even if the piston is net mechanically drawn back.
[0024] operating a pulse-generating piston can be useful in homogenising the ground around the borehole, even if the licjuid does not xeturn on the piston upatrokQ_ For example, a steady positive pressure may be maintained at the l~.c~uid supply from the reservoir, whereby the pulsing action do#s create cyclic variations in flowrate, but doeb not cau*e the flow to actually reverse during the upstroke. Especially when tk~e ground is barely saturated, this pulsing-without-reversing, though loot a* highly effective aft pulsing-with-reversing, still can be effective to fill the interstitial pores and spaces more completely than simply injecting the liquid under pressure, and can be effective to advance the saturation more as a flat franc than as a fingered fiont.
{0025] Also, even if the situation is such that the favoured surge- or slosh-pulsing (i.e pulsing-with-reversing] can be achieved eventually, it might be necessary first to go through a pulsing-without-reversing staga_ Then, gradually, as coherence of the injected body of liquid is procured, pulsing-with-reversing takes over, leading to the great increases in saturation capacity, and improved homogeneity, of the ground.
[0026] Tf there is to be any chance o~ flow reversal during the upstroke, of course the (pr~assur.i red) su~aply of make.-up liquid should be interrugl~ed du: ~y; t;.,e upstroke, using the valve 70.
j0027) Especial l;~ .-it yr:ee.:~~.or depths, ~aften the.rc: i.:; not ::rough porosity resilience, and l.ha pit;ton must be mechanically drawn back on the return stroke. Thifi can be done using Compressed air, from the surface, as shown in Fig 5. Apart from the forced withdrawal of the piston, the Fig 5 apparatus operates similarly to the Fig 4 apparatus.
(0028] gig 6 shows a set-up in which pulse* are created without the use of a mechanical piston. Here, air pressure is built up in an air chamber 74. When the valve 76 is opened, this pressure is dumped into the inner-tube 41, which causes the liquid in the inner-tube to pass out into the surrounding ground through the exit port.
At the end of the expulsion, the excess air pressure in the inner-tube is released at the valve 7B, and a fresh charge of tttaka-up liquid is admitted through the valve 7D. Liquid depth sensors, pressure sensors, etc, may be prov~,ded and used for timing the sequence of valve openings And closings, as reguired. Some of these items are shown in Fig 7.
(0029 The described ways of initiating the movements of liquids should not be regarded as exhaustive, and other effective ways of creat~.ng the pulses are within the competence of skilled designers of down-hole machinery. For example, a piston can be driven by means c~f an electric actuator, which has the benefit of being highly aOntrollable as to speed, acceleration, stooping points, etc.
[0030 The problems addressed by the apparatus as described herein arise mainly in the looser ground materials. The tighter (less permeable) ground materials tend to close tightly against the wall of the tube of the drive-point apparatus. and the tendency of liquid to leak upwards, around the tube, is minimal in tight soils.
Alan, the loose soils, in which the nroble~; occurs, tend to be near the surface, i.e: at shallcoa depth, which is the area of preference fGr usage of the drive-poi~it type of apparatus.
[003t] Thus, the invention preferably .is used when the p~.rmeability, or hydraulic conduct.ivi.ty, of tk~e ground is looser than about 0.7. cm/sec. The hydraulic conductivity of the ground is measured as the velocity of the liquid, in cm/sec, through the ground, per unit of imposed pressure gradient. The imposed pressure gradient is dctuahy dimansionlesa, in that it .is measured as a dxop of so many 0110. of pressure head, per cm of length along the direction of the velocity. A permeability of 0.1 cm/sec is aS9ociated with fine silt or till. The clays, gsneraliy, are so tight that no steps need be taken to prevent upwards leakage. The invention is xuitable for use with very loose soils, such as laxqe-gra~,ned gravels.
(0032] The packer itself takes up some annular space even when uninflated, and the uninflated packer should not be the radially-outex>aost component pf the drive-paint structure, or ~.t might be damaged by contact with the ground material as the structure is driven dowritaards into the ground. Thus, preferably, the drive-head 23 is of a greater diameter than the overall diameter of the uninflated packer.
Claims (18)
- Claim 1. Apparatus for adding a liquid into porous ground material, wherein:
- [2] the apparatus includes a drive-point structure, which is capable of being driven, from the surface, into the ground;
- [3] the drive-point structure includes a tube, comprising a tube wall, which defines an interior chamber;
- [4] the apparatus includes a source of a liquid, the source being located at the surface, and includes a means for transferring the liquid therefrom into the chamber;
- [5] the tube wall includes an exit port, through which the chamber is in liquid transfer communication with the ground material outside the apparatus;
- [6] the apparatus includes an expandable packer, and a means for expanding same;
- [7] the packer is of annular configuration, and is located radially outside the tube wall, between the tube wall and the ground material;
- [8] the packer is located about the level of the exit port;
- [9] the packer is effective, when expanded, to exert pressure inwards against the tube wall and outwards against the ground material; and
- [10] the structure and arrangement of the packer, when inflated, is such as to provide a seal between the tube wall and the ground material, thereby to inhibit the passage of liquid upwards towards the surface from the exit port, outside the tube-wall.
Claim 2. Apparatus of claim 1, wherein the tube wall is liquid-tight, above the level of the exit port, in the sense of being free of through-openings through which the interior chamber could make liquid transfer communication with the ground material outside the drive-point structure.
Claim 3. Apparatus of claim 1, wherein:
[2] the drive-point structure includes a drive-head, which is positioned as a bottom-most component of the apparatus;
and [3] the drive-point structure includes a drive-strut, which is mechanically robust enough to transmit driving forces from the surface down to the drive-head.
Claim 4. Apparatus of claim 3, wherein:
[2] the apparatus includes an operable driving means, which is effective, when operated, to drive the drive-point structure, drive-head first, down into the ground; and [3] the driving means is effective, when operated, to drive the drive-point structure downwards, substantially without rotation of the drive-point structure.
Claim 5. Apparatus of claim 1, wherein the ground material in which the packer is located is relatively loose, having a permeability no tighter than 0.1 cm/sec.
Claim 6. Apparatus of claim 1, wherein the depth to which the drive-head of the drive-point structure is driven is no more than about fifteen metres.
Claim 7. Apparatus of claim 1, wherein:
[2] the tube of the drive-point structure includes an inner tube and an outer tube, and the outer tube is movable upwards axially relative to the inner tube;
[3] in a lowered position of the outer tube, the outer tube covers the exit port, and in a raised position of the outer tube the exit port is exposed to ground material around the drive-point structure; and [4] the apparatus includes an operable means, located at the surface, for raising the outer tube, which is effective, when operated after the drive-point structure has been driven into the ground, to raise the outer tube, and thereby uncover the exit port.
Claim 8. Apparatus of claim 1, wherein [2] the source of liquid includes a reservoir;
[3] the means for transferring the liquid from the source into the chamber is effective to place the liquid in the chamber at a substantial head of pressure; and [4] the means for transferring the liquid from the source into the chamber is effective to deliver the liquid into the chamber, and thence into the ground, at a sufficiently large volumetric flowrate of liquid as to saturate the ground material around the drive-point structure, and to keep it saturated.
Claim 9. Apparatus of claim 8, wherein:
[2] the apparatus includes an operable, powered, pulsing means, which is located at the ground surface;
[3] the pulsing means is effective, when operated, to periodically and cyclically discharge respective substantial charge-volumes of the liquid out of the chamber into the ground material around the drive-point structure.
Claim 10. Apparatus of claim 9, wherein the pulsing means includes:-[2] - a variable-volume chamber;
[3] - an operable, powered, means for forcefully reducing the volume of the variable-volume chamber, and for then enabling the volume to increase, an a cyclic repeated basis; and [4] - a part for admitting make-up volumes of liquid from the source of liquid; and wherein:
[5] the pulsing means is located at the surface; and [6] the apparatus includes a transfer conduit, for transferring liquid from the variable-volume chamber at the surface to the interior chamber located in the ground material. - Claim 11. Apparatus of claim 9, wherein the pulsing means includes:-[2] - a pressurisable chamber;
[3] - an operable, powered, means for increasing the pressure of a fluid in the pressurisable chamber, and for then enabling that increased pressure to dissipate, on a cyclic repeated basis;
[4] - a port for admitting make-up volumes of liquid from the source of liquid; and wherein:
[5] the pulsing means is located at the surface; and [6] the apparatus includes a transfer conduit, for transferring liquid from the pressurisable chamber at the surface to the interior chamber located in the ground material. - Claim 12. Apparatus of claim 1, wherein the packer is both inflatable and deflatable, and the apparatus includes a means for inflating and deflating the packer, which is located at the surface.
- Claim 13. Apparatus of claim 1, wherein the packer contains a material, such as bentonite, that expands upon contact with water.
- Claim 14. Apparatus of claim 1, wherein the packer comprises an annulus of concrete injected under pressure around the tube wall.
- Claim 15. Apparatus of claim 1, wherein the exit port comprises several through-holes formed in the tube wall, and a protective screen physically prevents ingress of dirt into the interior chamber via the through-holes.
- Claim 16. Apparatus of claim 3, wherein the drive-strut comprises the tube wall.
- Claim 17. Apparatus of Claim 1, wherein the tube wall, in the region of the exit port, has an overall diameter of no more than ten cm, and the drive-head extends down into the ground, from the surface, no more than thirty metres.
- Claim 18. The use of the apparatus of claim 1 to inject a remediation liquid into a body of contaminated water in an aquifer.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0407309.4 | 2004-03-31 | ||
| GB0407309A GB0407309D0 (en) | 2004-03-31 | 2004-03-31 | Enhancement of flow rates through porous media |
| GB0411244A GB0411244D0 (en) | 2004-05-20 | 2004-05-20 | Multi-well enhancement of flow rates through porous media |
| GB0411244.7 | 2004-05-20 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2502800A1 true CA2502800A1 (en) | 2005-09-30 |
| CA2502800C CA2502800C (en) | 2015-06-16 |
Family
ID=34575765
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2502800A Active CA2502800C (en) | 2004-03-31 | 2005-03-31 | Enhancement of flow rates through porous media |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA2502800C (en) |
| GB (1) | GB2412675B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8069914B2 (en) | 2007-10-05 | 2011-12-06 | Canasonics Inc. | Hydraulic actuated pump system |
| US8113278B2 (en) | 2008-02-11 | 2012-02-14 | Hydroacoustics Inc. | System and method for enhanced oil recovery using an in-situ seismic energy generator |
| US8851169B2 (en) | 2009-09-04 | 2014-10-07 | Harold J. Nikipelo | Process and apparatus for enhancing recovery of hydrocarbons from wells |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB0618837D0 (en) * | 2006-09-25 | 2006-11-01 | Wavefront Energy & Environment | Rapid opening valve for use in boreholes |
| GB0817500D0 (en) | 2008-09-24 | 2008-10-29 | Wavefront Reservoir Technologi | Injection of liquid into boreholes, with suck-back pulsing |
| GB0907081D0 (en) * | 2009-04-24 | 2009-06-03 | Wavefront Reservoir Technologies | Environmental tool for pulsed injection of liquids |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5532849A (en) * | 1978-08-30 | 1980-03-07 | Sato Kogyo Kk | Grouting method |
| US4545702A (en) * | 1982-07-02 | 1985-10-08 | Toa Grout Kogyo Co., Ltd. | Boring-injection device, method for improving ground by means of the device and method for investigating ground state by means of the device |
| DD271349A1 (en) * | 1988-03-31 | 1989-08-30 | Bitterfeld Braunkohle | PROCEDURE FOR INSERTING AND OPERATING PROBES IN LAX |
| GB9706044D0 (en) * | 1997-03-24 | 1997-05-14 | Davidson Brett C | Dynamic enhancement of fluid flow rate using pressure and strain pulsing |
| US6604579B2 (en) * | 2002-01-03 | 2003-08-12 | Kejr, Inc. | Pressure activated injection probe |
-
2005
- 2005-03-31 CA CA2502800A patent/CA2502800C/en active Active
- 2005-03-31 GB GB0506521A patent/GB2412675B/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8069914B2 (en) | 2007-10-05 | 2011-12-06 | Canasonics Inc. | Hydraulic actuated pump system |
| US8534353B2 (en) | 2007-10-05 | 2013-09-17 | Canasonics Inc. | Hydraulic actuated pump system |
| US8113278B2 (en) | 2008-02-11 | 2012-02-14 | Hydroacoustics Inc. | System and method for enhanced oil recovery using an in-situ seismic energy generator |
| US8851169B2 (en) | 2009-09-04 | 2014-10-07 | Harold J. Nikipelo | Process and apparatus for enhancing recovery of hydrocarbons from wells |
Also Published As
| Publication number | Publication date |
|---|---|
| CA2502800C (en) | 2015-06-16 |
| GB2412675B (en) | 2008-02-20 |
| GB2412675A (en) | 2005-10-05 |
| GB0506521D0 (en) | 2005-05-04 |
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