CA2215652A1 - Chemical treatment device for well and pipeline applications - Google Patents

Abstract

The invention provides a method and apparatus for applying chemical treatment to wells and into pipeline systems employing a pressurized gas system. A further embodiment of the device provides for unattended treatment without the assistance of a human operator. A
timer or remote activator is attached to the chemical supply and pressure system and when the timer or remote activator is triggered, a metered dose of chemical is shot down the well or into the pipeline. Variants including the attachment of more than one chemical source as well as the addition of a circulation loop to further improve treatment for wells, are illustrated. The invention removes the need for manual initiation and handling of such treatment cycles. The method and device represent a significant improvement in terms of manufacturing and operating simplicity over conventional prior art pump application systems, as well as being safer and potentially less harmful to the environment through the removal of the human element presently required. The device could be used in oil, gas, water treatment or other applications requiring chemical injection.

Description

SEP. -16' 91(T~vE) 11 35 SK J~ISTI~E ~IUIL L~l~' TEL ~106 1~; 0581 P. 006 - Pa~e 3 -CHlEMl~AL TRE~TMENT ~E~ICE FOR WELL ANI) ~PELINE
APPLICATIO~S

This inventio~ ~eals w~th the field of wells and pipelines, and more spec~ ally with a method of apply~n~, chemical t~e~tment to oilfield wells and pipelines more a~cura~ely than the preser~t pra~hOe. ¢ost sav~gs, s~ety and environment~l prote~io~ a~e the Rln~m~n conce~ns zddressed by this inveMion.

B~CKGROIJNI):

The o~going Tn~int~n~r~e of produci~g oil wells and pil~P-Iines is a major industry. O~ce a well ~as been dnlled and brought into produçtion, vanous rn~inten~n- e procedures need to be c~rned o~ on bnth the e;~u;p~e~l as well as the well itself, in order to keep things runnin~ smoothly. One of the rn~int~n~n~A procedures which needs tO be kept up on a r~ lar basis is the control of c0--4s;~4 microbial and paraffin deposits o~ other bLlild-ups which rnight ~egatively af~ect the opera~ion of the wcll or pipclinc, includillg by restriGtin~
the flow ~ neter ~nd degrading the equipment. Ch~mic~l ~eatment is o~en used to tissolve build-ups, m~int~in flow and cont.rol corrosion p~oblems - protectin~ the well ou~ner's in~astructu~e ~nd the en~onment Two methods of ap~lic~on a~e available to oil and gas ~omr~nieS to achieve ~hrmir.~l ofthei~ f~çilit~P~, depen~Pnt upon the c~ us~ies ~elected for eR¢h well. The first ~ne~od is a continuously ~pplied rh~mit~l by m.o~ nir~l means. The secon~ Ir ethod is the application of chemical doses on a re~ r batch interva~. ~though both of these methods S~P. -16' 91~TlE) 11:35 SK J~STICE ~IUIi LAW ~EL:3~6 187 0581 P 001 have their place in oilfield m~inten~nce pro8rams, ~here are definite draw~acks ~so~tPd l~vith each.

In th~, case of continuollsly applied tre~rrn~nt~ aint~n~n~e is required on the equipment regularly, as well as pe~o~ic mon-tor~l~g to en~ure that the ~u~ect treatment dos~ge is being delivered. Small daily conç~ Ons ha~e alway~ bee~ problenla~c with this method. The se~ondmethod, periodicbat~tre~ nt, requires physic21 appli~alion oftheproductsusing mP~ ;r~l pres~ur~ equ;rmpnt Both ufthese scen~rioi require human intervention on an ongoing basîs. Thc oil w¢ll ~ ht need to be trea~e~ with rnore ~an one ehemi¢al, on a d;~e~ nent cycle than the first~ which requires a devotlon of even rurther manpower to oil well mai~tenance and ~Jea~es an even Tnore ~o~nrlir~ted time line for the m~intpn~nr~e crews to meet.

This type of Ll~dL~ lL re~sime requires oil produccrs or m~int~n~nce CO~ ;eS to have crews driv~ng around the field on a timely bas~s pe r~r,~ g th~s type of tr~tI"~ ,I The proble~ ~ith the current m~nual method of chemical tr~-~ t~nPnt~ alon~ w~ bein~ reliant on and sllsceptible to h!unan intera~i~ and error, is e~;.l)d~cd in oil-producing re~3~ons ~th harsh c~imates or te~ain~ such as Can~da and Rus3ia for exa~nple, where it mi~ht be terribly d~fflcult to reach the wells ~om time to time to treat tllem. An wlatte~ded automated metho~ of a~minictenn~ such chemical lrfi~r~ l If'' 1l ~ would address these problems.

Produ~t c~"IAir~r"enL is also an issue~ both in tenns of the hu;n~ operators and the e~ o~ , a~ repeated c.he~ l spilla~e a;~d contact is po~sible A closed systeln requinng little to n~ ntenA~ce and millimi7~ ch~rnic~l ~r.t~ct ~ith operators and enviromnent would be p~eferable Simil~r problems are enc~unt~ed in industnes as diverse as water treatment and pulp and paper m~mlf2~urin~ where che~ic~l injection i5 required either a~ a tre~meDt or process SEP.-16'91(T~ 3~ S~ JUS~I~E ~l~'IL LA~ TEL:3G6 78' 0581 P.008 paralrleter. The s~me pro~lems ~ld be encou~tered in thos~ appli~a~ons ~here conven~onal mech~ni~ pu~npin~ devices or the like are used.

S~IARY 0~ TION

It is the object of the preRnt invention to prov~de a me~od and ap~a~atu~ for the chemical ~reatmerlt of wells and pipeli~cs usin a pressure systeln that has ~al po~er ~e~uire~ents, few Tnov~n~ parts and is more easily oper~ted and m~int~in~d than tho~G
tre~tlnent systems in current use.

~t is the filrther o~ect of the invention to provide for a method and apparatus for the l~r.~tten(le~ ehe~ical ll~e~"e,ll of wells and pipelines7 requir~ng no regular human intervention to ~rcornr~ the va~ious tre~t~ne-~t~.

It is the fi~th~ abject of the inve~tion to provide for a method a~d apparatus for the ca~ L~e~ll of wells and pipelines whi~h is safer to operate and safer fior the en~ O.~ .L than the m~tho~ls of co~vention~l use.

The device accomplishes these objects CO~ JI ising ~bst~nti~lly at least one chem~cal storage l~S~Oll. ope~atively cnlln~v~e~ to tbat poItion cfthe well or pipeline req~!inng ~eatment with the chemical; gas pressure means to force ~he ~ h~mi~l out of the chernic~l stora~e reselvoir thraugh the operati~e conn~tiQn into the ~ell or pi~eline; and rh~m;r~l dispersal mean~ to control the volume and timing of the flow of chen~ om the chPmin~l stora~e reser~roir to ~he well or pipeline. ~any vanations on this basic configuration ~an be conter~pl~t~

The rh~rr~ l storage reservoi~ could be operati~ely c~mnected to the well or pipeline by h SEP -16' 9'~TUE) 11 .~6 SK JUSTICE ~lUlL L~A~ TEL:30~ ,87 05~1 P. 009 eh~rrtic~tI condl~it h~v~ng a first end ~nd a second end~ ~he second end of the .~.h~ ql cosltduit being corme~ted ~o the urell Or Pir~ ; ~d the chemiç~I ~tor~e reservo~r wTln~ l to ~he first end of t~e ~hernical ~ndL~it Yia a controll~l¢ val~e.

Tne cherr~i&al storage re3ervoir could be a pressurized ~essel ~d the ~as pressure l~leans a sour~e of p~sctlri7~d gas ~Gting on the chernlcal w~ in the p~ec~1n~ed vessel.
Conventional pressure-rated tank3 could be used as the chemical storage rese~vo.r or reser~oirs. The ~as pressIlre means could comprise a gas cylinder with a re~lator. The re te~ g~s pressure COUIG be a~ ct~thle, for more flexibility in the confi~uratlon of the unit. ~itrogen, or other safe or inert ~ases, could be used as tke pressu~d Qas in the ~as pressure n-eans Various methods of conn~ n ofthe gas p~ess~e means to the che~ical storage rese~ oir, ~d ~e r~Tnic~l storage reservoir to the chernic~T ¢ond~iit, could be u~ed. Por cxamyle, the ~int of a~ h". ,l of ~e ~as press~re means to the ~,e ..;~ ~l storage r~servoir could be at tbe top of the rhPrni~l storage re~er~oir, and ~e controllable ~alve at a point near the bottom ~f the ~ m;r2~ stor3~e reservoir. Altemat~vely, the point of ~tt~chm~nt ofthe ~s pressure mean3 ~nd the corl~rol~able valve to the ehell~iGal stor~ge rese~oir n~i~ht be at the t~p of the chYn~ical storage ~esen~oir, the controllable valve fiLrther compnslng ~ feed conduit~ the fir6t end of the feed condwt ~ctendin~ to a p~int ~nsidc and ne~r the bott~rn of the ch~ l storage reser~oir, and the second end of the fe~d conduit conneeted to the conkollable valve.

~he devi~e, for use on ~ w~l in~ a flow line carTying the p~du¢ed wellbore fluidpumped ~om wellhead at th~ ~op of a well cas~ng to a ~torage vessel or plpeline, çould ~lso add circulatioll me~ns to con~ol~abl~ divert produced ~el~o~e fl~id from the flow line of the w~ll back to the re~ervoir at the bottom of the well This ruight include a cireulation v~lve. In one embodiment, the circulatin~ m~n~ could comp~ise subst~nt~ y a pipe CA 0221~6~2 1998-01-19 attached at one end to the flow line of the well and at the other end to the well casing, being the first and second circulation attachm~nt points; and a circulation valve between the pipe and the flow line at the first circulation attachment point. A one way valve could also be added between the pipe and the well casing at the second circulation att~chment point to ensure one-way flow into the well casing through the circul~ting means.

Both the controllable valve or valves, along with the circulation valve in the case of the embodiment having circulation means and the regulator on the gas pressure means, could be either m~nll~lly or automatically actuated.

In the case of automatically ac~hlated valves, a device controller could be added to operate the device in the absence of a human operator. The device controller could include a timer or a programmable logic controller with a programmable cycle for the application of chemical to the well, or could alternatively include a remote control whereby the device could be actuated remotely by way of a radio signal, telephone modem or otherwise. In any case, the device controller could be configurable from a remote location.

More than one chemical storage reservoir could be used, attached either to the same or independent pressure means, for the application of di~el e..L products to the well or pipeline.
The device controller, in the case of automatically actuated valves, could be enabled to control the controllable valves individually and independently from one another. In such an embodiment the gas pressure means might also be individually and independently regulated for each chemical storage reservoir, or a separate gas pressure means could be used for each chemical storage reservoir.

The present invention provides a method of chemicallytreating wells or pipelines comprising providing at least one chemical storage reservoir operatively connected to that portion of the well or pipeline requiring treatment with the chemical; forcing the chemical out of the CA 0221~6~2 1998-01-19 chemical storage reservoir through the operative connection into the well or pipeline using gas pressure means; and controlling the volume and timing of the flow of chemical from the chemical storage reservoir to the well or pipeline using a valve. The valve can be controlled by a programmable or remotely activated control device, or can be m~nll~lly activated.

The types of wells or pipelines contemplated include those used in oil, gas, water or pulp and paper applications, and others. Other uses of the device, such as for injection into a tank or vessel, are also contemplated.

DESCRIPTION OF THE DRAWINGS:

While the invention is claimed in the concluding portions hereof, prerel 1 ed embodiments are provided in the accompanying detailed description which may be best understood in conjunction with the accompanying diagrams where like parts in each of the several diagrams are labeled with like numbers, and where:

Figure 1 is a diagram of an embodiment ofthe invention used on a pipeline, with the controllable valve near the bottom of the chemical storage reservoir;

Figure 2 is a diagram of a further embodiment of the invention including a circulation loop used on an oil well, with the controllable valve near the top of the chemical storage reservoir;

Figure 3 is a diagram of the embodiment of Figure 2 with the addition of a remote device controller, a second chemical storage reservoir and a second chemical feed ~tt~chment to the flowline of the well, with a single gas pressure means.

SEP.-16'91(TUE~ 31 SK JUSTICE CIUIL LA~ TEL:306 781 Oj81 P.012 I~ET~ll Fl) DESCRIPTION 0~ TE[E ILLUST~TED El~BC)DIMENTS:

Both wells and pipelirles require similar chernica~ treatme~ts to ~ optirnal ~w n Pt~r and safe opera~ing ~onditions. The present ~venti~n deals in the field oftreatment of both wells and pipelines, and wh~e the tenns 3nd c~ncep~ of wells and rip~ eq will be used i~tert~h~n~P~hly herein, the invention Is intended to be pra~ced on both wells and pipelines and both applications are cont~ ted within the scope ofthe claimed invention.
Also c~ e~l)pl~ted ~nthin the scope of the invention is the use of the device in other ~hemi~l in~ectio~ app~ications su~h as for injection of ch~ic~ls into a tank or pro¢ess vessel.

While thi~ specificdtion speaks generiçally ~f wells and pipelines, it is specifieally intended for use on oilfield wells ~nd pipelir~5 It will aIso be u~derstc~d f~lt the d~ce could be used for the trea~nlent of gas, water or other wells and pipeli~es also and that such app!ir~tiQn~ along w~th ~y n~cesS~ry controls or mo~lifica~ions required are cQnt~mrl~ted ~ithin the scope of the invention.

Figure 1 shows a .~iml)lified diagram of a ~oasic emboll;ment ofthe deYice lû in ~tt~rhment to a pipeline 1, comprisin~ s~lhct~nti~ily at least one ~h~mi~l storage reservoir 14, operatively cr nn~cte~3 tu that portion ofthe pipeline 1 requiring treatment with the ch~mic~
~s press~e mea~s to force the r~l~rmir~l 23 out ~f the cherni~al sto~age reservoir 14 throu~h t~e operative connection into the pipeline 1, and ~hP.mic~l dispersal Illeans to control the volume and ~iming of the flow of chen~i~l 23 from the rh~ ! stora~e reservoir I~ to the pipeline 1. The operative connection ofthe device 10 to the pipeline 14 i5 by way of the chemical conduit 11, which is att~rheA to the ~.hf~mi~Al dispe~l means at its first end lZ and to the pipe~ine 1 al its second end 13.

The gas pressure means is a pressurized gas cylinder 1~ and a regulator ~0 on the outlet of SEP -16 97!TliE) 11:31 SK JUSTI~E CIUlL L.~W TEL 306 '87 Oj8! P.0I3 - Pa~e 10 -the cylinder 19. The outlet of the regulator ~0 is connected ~a gas line ~ l to a ~a5 ~nlet port nn the top of ~e eh~mi~al storage rese~oir 14, thefeby pr~ ~n~ the ~hPm~
storage reser~oir 14. The re~u1~t~r 20 keeps the g~s press~e in the chemit~l storage reservoir 14 ~I~S~t as the leve~ of ch~rni~l 23 in the reservoir 14 drops requiring more ~as 22 to o~upy the void le~ in the (~h~mi~l storage reser1~oir 14 It wil1 be under~t~od that ~e gzs pressure irl the chto.mic~l stora~e reservoir 14 m~st be ~eater than ~le pressure in the pipeline 1 in order to force the chern~cal into th~ pipeline.

The c~mie~l storage reserwir 1~ n~ight also have a pressure relief valve for s~fet~
purposes, although the presence and operation of such valve is not directly n~aterial to the present in~ention.

~e regulator 20 also pro~ides a me~ns to adjust the ~as pressu}e ~ the ch~mir~l reservoir 14 - the pressure o~the systeln ~an be ~h~n~ed by adjus~ng the gas re~lator 2a. In this particul~ embodiment it is contPmrlAt~d ~at nltro~e~ would be used ~s th~ pressuri~ed ~s 22. It will be understood, however, tha~ other s~fe E~dlor inert ~ases ~i~ht also be used and are ~vllle~ t~d within the scope ofthe Invention.

In the embodiment of Figure 1, the che~nie~l dispersal me~ns to control the voEume a~d t~ ofthe flow of chernic~l 23 from thç chem~cal st~rag~ res~oir 14 to the pipcline I
is a çon~o~able val~e 17. The ~ontrollable vsl~e 17 is ~rt~h~d at a point near the bottom 16 of the c.helni¢~l storage rese~oir. When controllable ~ e 17 is opened, the ~hem~oal 23, irl response to the force exerted by the gas pressu~el flo~s thloug}l the vahre 17 a~d through the rh~mir~ nduit 11 and into the pipeline 1 In this ernbodiment, the co~trollable va~Ye 17 incorporates a one way fieahue as well, allowing for ~ow toward Ihe well or pipeline only~ d prev~nting any bac~ flo~ into the chemical storage reservoir 14 in a c~se where, for whatever reason, the pressure in the well ~r pipeline exceeds the pressure in tbe r~ernic~l storage reservoir 14, which might force produced wellbore or SEP.-16'91~Tl'E) 1!:31 SK JUSTI~E CIIJlL L4~ TEL 3~6 787 0S81 P 014 pipeline ~uid or gases into the cherrli~al storage reservo~.

The controllable valve 17 can ei~her be man~ ly or automa~ically operated. Tn the case of a m~nual valve, the ~hPmir~l 23 would be applied to the pipeline I by sirrlp~y opening the controllable valve 17 f~r a set amount of time until the ~ up~ e amou~rt of chenucal 23 has been "shot" into the pipelirle 1 rll the c~se of a ~ ~c~ 1 v~l~e 17, that ~ lt be controlled by a timer or device con~oller for llnA~tPn~ed treatment oftlle pipeline.

Either ~e ~he~nic~ls 23 or the ~as 22 c~n be reloade~ by the occa3ional attendance of ~n u~ lor However, as can be seen, the normal operation ~ftlhe device lO does not req~ire any corltact bet~een the operator or the env ronmem and t~e chemicals being applied. A
closed systen~ e~sts. It is ~I;ci~ th~t if the device is buil~ to 3uffioient scale it may only need to ~e recharged once or twiee per y#lr.

~i~ure 2 shows a second em~odiment of the invention lO in ~se on a conventional oilfield wçll ~ well 2 consists of a-l outer casinC ~, within which a smaller dia~eter tubing 4 exteads down i~t~ the oil-producin~ tion. The a~ea bet~een the inside ofthe casing a~d the outside of the tubi~g 4 is called the annulus 5 of the ~ell The tubing 4 is a~chored in the c~ 3 at the point at w~ich the oil will ~e draw~ f~oln the formation. The casin~ ~ is perforated, aIluwing oil to ~ow into the ~ ulus 5 and tubing 4 ~om th~
iO~. The do~nhole flu~d level is det~ed by the ffim-~tit~n pressure ofthe ~ell ~1d other geological fiactors. In any event there is arl amount of fl~id at the bottom of the well at the pump~ poi~ which is ~e do~nhole ~uid ~eserv~ir 6. Va~ous ~pes of liR systelns are used to li* the wellbore ~ 9 up the t lbul~ 4 ~rom the reser~oir 6, but the type of pump used is not material to tl)e present descnption. At the v~el~head 7 there is a ~owline 8 into which the produced wellbore fluid 3 is pumped, either to a h~lding tal~k for evensual haulin~ or to a larger pipe~ine in the field.

CA 0221~6~2 1998-01-19 In conventional chemical treatment, the chemical to be treated is simply poured or pumped down the annulus 5 ofthe well. The chemical eventually finds its way down the casing walls to the producing region of the well, and flows into the tubing 4 and back up the well, if sufficient chemical is applied to reach the bottom of the casing 3, dissolving deposits and other obstructions on the way down the casing 3.

The embodiment of the present invention shown attached to the oil well of Figure 2 comprises a chemical conduit 11 having a first end 12 and a second end 13; a chemical storage reservoir 14 having a controllable valve 17 leading to and connected at the first end 12 of the chemical conduit; the second end 13 of the conduit connected to a port leading to the well ~nnllhls 5, said port located on the well head or well casing, and gas pressure means as illustrated in the embodiment of Figure 1 and previously described.

The embodiment of Figure 2 demonstrates a second method of attachment of the gaspressure means and the controllable valve to the chemical storage reservoir. Thecontrollable valve 17 is attached at a point near the top 15 of the chemical storage reservoir 14, with a feed conduit 18 inside the reservoir extending down to a point near the bottom 16 ofthe reservoir. The gas pressure means 19/20 is connected to a gas inlet port on top 15 of the chemical storage reservoir in such a manner as to pressurize the chemicals 23 into and through the feed conduit 18. When the device 10 is operated the downward pressure ofthe pressurized gas 22 on the surface ofthe chemicals 23 forces the chemicals up through the feed conduit 18. As indicated above, nitrogen or other inert gases could be used.
Again, the controllable valve 17 can either be m~nll~lly or automatically operated.

The embodiment of Figure 2 also employs a circulation loop 24, to circulate a limited amount of produced wellbore fluid 9 down the annulus 5 of the well before and/or after the chemical treatment. This will allow for a pre-flush in the well before the chemical is applied, and if produced wellbore fluid 9 is circulated down the annulus 5 for a time after the CA 0221~6~2 1998-01-19 chemical treatment that fluid 9 will ensure that all ofthe chemical treatment is carried to the bottom of the well for treatment. In the illustrated embodiment, the circulating means comprises substantially a pipe 24 ~tt~ch~d at one end to the wellhead 7 and at the other end to the well casing 3, being the first and second circulation attachment points 27, 28; a circulation valve 25 between the pipe 24 and the wellhead 7 at the first circulation attachment point 27, allowing flow into the pipe 24 from the wellhead 7; and an outlet check valve 26 between the pipe 24 and the well casing 3 at the second circulation ~tt~çhment point 28, checked against flow into the pipe from the well, wherein the second end 13 of the chemical conduit is attached to and feeds into the pipe 24 at a point between the circulation valve 25 and the outlet check valve 26. By the use of the outlet check valve 26, one-way flow through the circ~ ting means is ensured. When the circulation valve 25 is opened, some ofthe produced wellbore fluid 9 under pressure in the wellhead 7 will flow back down the annulus 5 to the reservoir 6, the rem~in~ler of the produced wellbore fluid at the wellhead contimling through the flowline to the holding tank or pipeline. The pumping of fluid 9 back down the annulus 5 in advance of the chemical application has the effect of loosening up or slickening any deposits which have built up on the walls of the casing and tubing, allowing for smoother eventual downward flow of the chemical application. At a point then after the circulation loop had been engaged, the controllable valve 17 could be opened and the chemical treatment would enter the pipe and flow down the annulus of the well. After the controllable valve 17 was closed the circulation valve could be closed, or could be allowed to remain open for a short further period of time to circulate a further quantity of produced wellbore fluid back down the casing in the ~nn~ , which would ensure that all of the chemicals applied were carried down the well. The feed pressure for the produced wellbore fluid into the circulation loop would be provided by the well pump, as the well would remain in production while the treatment was applied - only some of the pressure of the well would be diverted at the wellhead for the necessary period of time to accomplish the treatment. For safety purposes, one way valve 26 prevents any flow from the annulus 5 back into the circulation loop 24.

CA 0221~6~2 1998-01-19 Similar to the controllable valve 17, the circulation valve 25 could also be either m~nll~lly or automatically controlled.

Figure 3 demonstrates still more of the flexibility of this concept. While still similar in concept to the embodiment of Figure 2, the embodiment of Figure 3 has two chemical storage reservoirs 14, enabling the individual application of more than one treatment to the well.. Each chemical storage reservoir 14 has its own controllable valve 17 connected to the chemical conduit 11. The dispersal valves 17 incorporate a one way feature which prevents any flow of one chemical into another chemical storage reservoir.

Chemical application volume can be controlled both by the time the controllable valve 17 is open, as well as by the gas pressure setting (the regulator 20) - as the pressure is increased, more chemical will be shot within a shorter time. A single gas pressure means is shown in the embodiment of Figure 3 . An alternative to the use of a single gas pressure means which will be obvious to those skilled in the art and which is contemplated within the scope of this invention, would be the use of a separate gas pressure means for each or some group of the chemical storage reservoirs in a multiple reservoir system.

Also shown in the embodiment of Figure 3 is a device controller 29. Where automatically actuated valves 17 are used in the device, it will be possible to provide a controller to open and close them in the absence of a human operator. The device controller 29 could include either a timer or programmable logic controller, with a programmable cycle for the application of chemical to the well, or could alternatively include a remote control whereby the device could be actuated remotely by way of a radio signal, telephone modem or otherwise. In either case, the device controller 29 could be configurable from a remote location. The device controller 29 in the present embodiment consists of a programmable logic controller, which is linked to the controllable valves 17 and the circulation valve 25 which in this embodiment are solenoid actuated valves. When the controller 29 triggers a SEP.-16'9~TUE) 11:3~ Sl~ JliSTICE CIUIL LA~ TEL 306 ,87 0581 P.Oi8 -Pa~e 15-solenoi~ the respective valve is open~d and ~r~X~ d chemicals ~ow ~om their c~e~cal storage reservoir 14 throu h the che~ical conduit 1~ to the cir~ation loop ~4. ~imilarly, the controll~r could open ar.d close the ~ircu]ati~n ~ !ve 25 for prepro~ d~ .,d intcrvals, prov~ding circul~io~ in tha circulaticn loop ~4 The addi~onal ~dv~nt~ge of a device controller over hu~ peranon, 31on~ ~th the o~vious sav~ng~ in cost and reduced cheT~uc~l risk to humans and en~ironment, is ~e ~ that the de~ice co~troller ~9 ~ould be proE~a~med wi~h intricate sched~Ile~ ior the applic~tion of more ~ ne type of ~Ltreatment (where more than one cherJ~ storage r~servoir is used).

The dev~ce controller ~ will control the amount of che~ s ad~ir~i~t~re~ to the well, alon~ with the timin~ of such treRtm~m The dev~ce controller ~9 can control the amG~t of chemicals dist~uted down the well shaft either by the administrztion of a t~med dose ~i .e.
the ~ength of dme for whlch the a~ or is ~n~ will control the amour~t of chemi~
or else the actuator could ~lso be rnodified to provid~ a mea~u~ed volume of chemicals.

An altem~tive to a ~i~er in the device controller ~9 would be to maLce the device contro]ler 29 ~nto ~ relnote cont~ol. By rernote control it is mear~t that the de~,ice could be actlI~ted by the use af a radio sigr.al, a t~lophol ~e modem or other such remote sctuating signals. This vvould aflow for even more ~ersarili~y and easier c~ntrol over the device 1 a3 it eauld be triggered ~om ma~y miles away and the restrictions of a manualfy altered timer cycle could be avoided.

In either case, of a ~emote con~l or a timer ~ t~e de~ nntroller 2~ a filrther v~nation wouldbe~oInakethe~ontroller29eaiilyconfigurablebythell3er. Thecycfesofthe~ner~, or a computer pro~ram which r~notely ~ctu~ted the devices in place on ~arious wells, could be configured and ~.h~ng~ easily. Irl the ca~e of a device controlle~ relying p~imalily on a tl~ner orl site, the ~lflitit~n of a remote c~nfi~lfa~n feature would be pref~able to an ope~ator havi~g to physically attend to ~ e the ~mer cycle. ~ either case, eithe~ local CA 0221~6~2 1998-01-19 or remote configuration, it is a further advantage of the invention to be configurable by the user. Variations such as these or others known to those skilled in the art are contemplated within the scope of the invention.

In the illustrated system, employing a pressurized gas system as the pressure means, the timer 29 is only required to operate the solenoid controllable valves 17 and the circulation valve 25, which keeps the power consumption and requirements of the device low. This is preferable, as batteries and/or solar power could be used in remote locations where no electrical power was available.

In operation of the device in the illustrated embodiment, the timer in the device controller 29 will actuate the application of chemicals down the annulus 5. The device controller 29 could first open the circulation valve 25. This would allow for the flow of produced wellbore fluid 9 from the wellhead 7 through the circulation loop 24 and back out into the well casing 3 through the outlet check valve 26, and by allowing circulation for a period of time before injection, any material rem~ining in the circulation loop 24 or the annulus 5 since it was last closed could be loosened up. At a point the device controller 29 would then open the controllable valve 17 for a period of time, which would cause the injection of chemicals 23 through the chemical conduit 11 into the circulation loop 24 and eventually down the well. Pressure in the chemical storage reservoir 14 is m~int~ined by the pressurized gas 22.
Once the timer 29 closed the controllable valve 17, the backing of produced wellbore fluid 9 into the chemical conduit 11 would be checked by controllable valve 17. The circulation loop 24 could be kept open for some period of time following the chemical injection to allow the chemicals 23 to circulate fully down the well. Then the timer 29 could close the circulation valve 25 and the regular production from the well would continue. Should the user prefer, the device could be modified such that the flowline could be separately treated with chemicals by opening another valve on an extension of the chemical conduit when the chemical flow is taking place, rather than simply being treated when the chemicals shot CA 0221~6~2 1998-01-19 down the annulus are pumped back up the tubing of the well..

The chemical conduit could be attached either within the circulation loop, or directly to the casing of the well.

More than one chemical storage reservoir 14 could be used, attached either to the same or independent pressure means, for the application of di~erel" products to the well. The device controller 29 could be enabled to control the controllable valves 17 individually and independently from one another. It will be understood that the addition of multiple chemical storage reservoirs 14, and the necessary control adaptations therefore, are contemplated within the scope of this invention.

The device controller 29 could also be configured to control the gas pressure regulators 20 on the gas cylinders 19, so that the pressure could be varied to adjust application volume or penetration.

Thus it can be seen that the invention accomplishes all of its stated objectives. The foregoing is considered as illustrative only ofthe principles ofthe invention. ~urther, since numerous changes and modifications will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all such suitable changes or modifications in structure or operation which may be resorted to are intended to fall within the scope of the claimed invention.

Claims (25)

1. A device for the chemical treatment of wells and pipelines comprising:
at least one chemical storage reservoir, operatively connected to that portion of the well or pipeline requiring treatment with the chemical;
gas pressure means to force the chemical out of the chemical storage reservoir through the operative connection into the well or pipeline; and chemical dispersal means to control the volume and timing of the flow of chemical from the chemical storage reservoir to the well.

2. The device of Claim 1 wherein:
the chemical storage reservoir is operatively connected to that portion of the well or pipeline requiring treatment with the chemical by a chemical conduit having a first end and a second end, the second end of the chemical conduit being connected to the well or pipeline; and the chemical storage reservoir is connected to the first end of the chemical conduit via a controllable valve.

3. The device of Claim 2 wherein the chemical storage reservoir is a pressurized vessel and the gas pressure means is a source of pressurized gas acting on the chemicalwithin the pressurized vessel.

4. The device of Claim 3 wherein the controllable valve is manually activated.

5. The device of Claim 3 wherein the controllable valve is activated by a signal from a control device.

6. The device of Claim 3 wherein the pressure of the pressurized gas in the gas pressure means is regulated.

7. The device of Claim 6 wherein the chemical dispersal means includes a control device activating the controllable valve into the closed or open position.

8. The device of Claim 7 wherein the pressurized gas is nitrogen.

9. The device of Claim 7 wherein the pressurized gas is an inert gas.

10. The device of Claim 7 wherein the regulated pressure of the pressurized gas in the gas pressure means is controlled by a signal from a control device.

11. The device of Claim 7 wherein the point of attachment of the gas pressure means to the chemical storage reservoir is at the top of the chemical storage reservoir, and the chemical dispersal means further comprises a feed conduit, the first end of the feed conduit extending to a point inside and near the bottom of the chemical storage reservoir, and the second end of the feed conduit connected to the controllable valve.

12. The device of Claim 1 for use on a well, where the well includes a flow line carrying the produced wellbore fluid pumped from the reservoir at the bottom of the well to a storage vessel or pipeline, said invention further comprising circulation means to controllably divert produced well bore fluid from the flow line of the well back to the reservoir at the bottom of the well.

13. The device of Claim 12 wherein the means to controllably divert produced wellbore fluid from the flow line of the well to the reservoir at the bottom of the well includes a circulation valve.

14. The device of Claim 13 wherein the circulation valve is manually activated.

15. The device of Claim 13 wherein the circulation valve is activated by a signal from a control device.

16. The device of Claim 15 wherein the chemical dispersal means includes a programmable or remotely activated control device activating the controllable valve into the closed or open position.

17. The device of Claim 16 wherein the circulating means comprises a pipe attached at one end to the flow line of the well and at the other end to the well casing, being the first and second circulation attachment points; and a circulation valve between the pipe and the flow line at the first circulation attachment point.

18. The device of Claim 17 further comprising a one way valve between the pipe and the well casing at the second circulation attachment point, said one way valve allowing flow only into the well casing.

19. The device of any of the previous claims wherein the number of chemical storage reservoirs is more than one.

20. The device of Claim 19 wherein the programmable controller can control the chemical dispersal means of each chemical storage reservoir individually and independently from one another.

21. The device of Claim 20 wherein the gas pressure means can be individually and independently regulated for each chemical storage reservoir.

22. The device of Claim 21 comprising a separate gas pressure means for each chemical storage reservoir.

23. A method of chemically treating wells or pipelines comprising:
providing at least one chemical storage reservoir operatively connected to that portion of the well or pipeline requiring treatment with the chemical;
forcing the chemical out of the chemical storage reservoir through the operativeconnection into the well or pipeline using gas pressure means; and controlling the volume and timing of the flow of chemical from the chemical storage reservoir to the well or pipeline using a valve.

24. The method of Claim 23 wherein the valve is controlled by a programmable or remotely activated control device.

25. The method of Claim 23 wherein the valve is manually activated.

LISTING OF DIAGRAM REFERENCE NUMERALS:

1. Pipeline; 16. Bottom of the ¢hemical storage 2. Well; reservoir;
3. Casing; 17. Controllable valve;
4. Tubing; 18. Feed conduit;
5. Annulus; 19. Gas cylinder;
6. Downhole fluid level/reservoir; 20. Regulator;
7. Wellhead; 21. Gas line;
8. Flow line; 22. Gas;
9. Produced wellbore fluid; 23. Chemicals;
10. Chemical treatment device; 24. Looped pipe (circulation means);
11. Chemical conduit; 25. Circulation valve;
12. First end of conduit; 26. Outlet check valve;
13. Second end of conduit; 27. First circulation attachment point;
14. Chemical storage reservoir; 28. Second circulation attachment 15. Top of the chemical storage point;
reservoir; 29. Device controller