Note: Descriptions are shown in the official language in which they were submitted.
CA 02331473 2001-O1-19
Bac~oRO» of T~ iNVErrrroN
(1) FIELD OF~'HE INVENTION: The invention pertains to a fluid injection
apparatus and
method with controlled volume displacement for use in the treatment of one or
more zones or
sections within a subterranean well.
(2) D ~SCRIF'TIOIV OF THE PRIOR ART: During the drilling, completion or
worl:over of
a subterranean oil or gas well, it has been necessary or desirable to place a
specific volume of a
"treatment fluid" such as an acid, a polymer, a "spotting" fluid, corrosion or
scale inhibitor, or
other similar and known chemical, such as cement, plastic, epoxy, ael, or the
like, in a precise
amount and at a precise location within the wellbore. This has been
accomplished in the past by
use of a "oailer" which is introduced into tL~" well on a wireline, or the
like. The bailer contains
a specific volum,: and is activatable due to aensiry differential of the
treatment fluici relative to
the natural fluid:; in the wellbore at the ~ime and location of treatment.
However. this long
established procedure is not entirely satisl~c~ory in highly deviated wells or
when tubing has
become ",.ork-screwed. " Additionally, when baker systems have been utilized,
and i~ is required
1~ that a specific, precise amount of treatment fluid must be injected into
the well, such specific,
desired amount of the placement or treatmEnt fluid may not be totally ejected
from the interior of
the bailer, thus r~cducing the anticipated ar~:i reqLired amount of treatment
fluid for tla; particular
zone application Even when this problem is overcome by the use of a "positive
displacement"
bailer system in which a gravitational weight bar is used to push a piston
with a wiper sc;al through
the bailer string, thus wiping the inside wall of the bailer clear, such
additional step is often times
extremely time consuming resulting in utilization of additional expensive
workover or other rig
time.
CA 02331473 2001-O1-19
The present invention addresses the problems associated-with such prior art
apparatuses
and methods.
Fig. 1 is an elevational cross-sectional view of the apparatus of the present
invention
introduced to a predeterminable location within a subterranean well and prior
to activation.
Fig. 2 is a view similar to that of Fig. 1 taken subsequent to activation of
the apparatus.
Fia. 3 is a view of an alternative preferred apparatus in the position as
shown in Fi~?. 1.
Fig. 4 is « view of the apparatus of Fig. 3 subsequent to activation.
Fig. 5 is a longitudinal cross secu~:na1 view of another alternative
embodiment of the
present invention incorporating plural chambers and piston means and shown in
the position prior
to activation.
Fia. 6 is :~ view of the apparatus of Fig. 5 subsequent to activation of one
of the piston
means in one of ~ha chamber elements.
Fig. 7 is a view of the device shown :n Figs. 5 and 6 subsequent to activation
of a plurality
of piston element: within their respective chamber means for discharge of a
plurality of treatment
fluids, either concurrently or in tandem.
Fig. 8 is ;m illustration of yet another embodiment of the present invention
wherein the
chamber means iv provided by the interior walls of the conduit introduced into
the subterranean
well.
SL1N~1~IA~ Y OF THE TNVENTX~
The pres~:nt invention provides a fluid injection apparatus with controlled
volume
displacement for use in ejecting a treatment fluid in a subterranean well. The
device is carriable
into the well on a conduit, such as continuous coil tubing, a workover string,
or by wireline.
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Preferably, the c~>nduii will be a workover string or continuous coiled tubing
or ocher conduit
having a fluid p:~ssageway interiorally thereof. The apparatus of the present
invention may
comprise a cylindrical housing having an interior fluid chamber for receipt of
the creatrnent fluid.
deans, such as threads, are provided at one' ;:nd of the housing for securing
the apparatus to the
conduit. Piston means are carried within the chamber for isolating fluid
within the chamber from
the passageway :md are movable from a first position whereby the chamber is in
expanded
condition retaining fluid therein to a second position whereby the chamber is
in a contracted
condition and the treatment fluid is ejected from the chamber into the Well.
h is contemplated herein that the apparatus of the present invention may be
carried into a
well on a condui:. other than one having an inm uior fluid receiving
passageway, such as by wire
or electric line. 1-Iowever, when such conduit is utilized with the present
invention, .means must
be incorporated therein in conventional fashio:: for providing application of
pressure to one side
of the pis°on means for moving same to c~:ntract the chamber and eject
the treatmew: fluid.
The apparatus may be provided in a form whereby it is not an independent tool
or
component specii ically carried by the conduit and is provided as an integral
component part of the
conduit. Moreover, the apparatus may be provided in a form in which tandem or
sequential
ejection of separate treatment fluids is accomplished by utilizing two or more
"stacked" chambers
and pistons either provided in parallel, horizontal or vertical alignment.
The present invention provides positive controlled volume displacement of a
treatment fluid
and can accommodate pumping volumes as Iuw as 3 gallons to 2 gallons of fluid
per minute. This
permits speciali::ed, conuolled pumping operations of expensive treating
chemicals, such as
polymers, chelatus, monomers, cross-lin.~ing agents, reaction catalysts, chain
stopp:rs, acids,
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buffering agents and the like. This controlled displacement insures that
treating fluids are not over
displaced and are located at the proper treatment interval within the well.
In one embodiment, the present inveuaon provides a diaphragm or similar
component,
housed within tr.e floating piston element, which is rupcurable or otherwise
op~:nable to a
passageway within the conduit for circulation in the trearment chamber and the
fluids in the well,
in one of many known fashions.
DESCRIPTTON 2F T~= PRE~RRED EMBOVIMEI~'TS
Now, wiW first reference to Fig. 1, there is shown the fluid injection
apparatus 10 of the
present invention secured at threads 11 to a conduit CT having a series of
radially disposed
pressure rylief pc-tts PRD immediate the lo~.erm~~;st end thereof that are
normally co rered by an
interior siding :sleeve mechanism (not shoe; n). As staled above, the conduit
CT may be
continuoLS coilea tubing, conventional wcSkover or drillstring, or the like.
The conduit CT has
a fluid passageway FP therein for introduction of a pressureable fluid for
activating tt:~: apparatus
10 as des~=gibed t~elow.
1~ The apparatus 10 comprises a cylindrical housing 12 secured at its
uppermoss end to the
conduit CT by tY~.e threads 11. The cylindrical housing 12 has an interior
smooth wall 12A' for
receipt of a flouting piston 13 having a upper face 13A in communication wi~;h
the fluid
passageway FP. A lower face 13B defines the uppermost, or one, end of a fluid
chamoer 20. An
O-ring seal 14 is contained within a circumferentially defined brooveway 14 A
around the
outermost circumference of the floating piston 13 for sealing movements along
tha smooth wall
12A of the interior of the .cylindrical housing 12.
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The cylin.irical housing 12 of the apparatus 10 also provides a piston seat
sub 12A having
an upwardly facing. inwardly extending shoulder abutment 12B for terminating
the lower travel
of the floating piston 13, as described, below. A port 12C is defined within
the piston seat sub
12A to permit filling of the fluid chamber 20 with the desired treatment fluid
prior to introduction
of the fluid apparatus 10 to the wellbore WB. The port 12C is sealed by
introduction of plug 12D
in securement within the plug port 12C subsequent to the filling of the fluid
chamber 20 ac the cop
of the well. The port. 12C and plug 12D may, of course, be deleted and the
apparatus 10 filed ac
the top of the well before introduction into the well.
A stinger element 12E is secured by threads 12E1 to the lowermost end of the
piston seat
sub 12A. The stinger 12E contains a bl~.:wout plug 15 which is secured in
place to block the
lowermost end on the fluid injection appara~zt~ i0 by means of a series of
radially extending shear
pins I3, 14. FIu:~.d communication between the exterior of blowout plug 15 and
the interior of the
stinger 12E is poevenced by means of provision of an O-ring seal element 16
housed within a
groove loA.
lj As shown in Fig. 1, the apparatus 10 has been run into the wellbore WB for
desired
treatment of fractures F through perforati:~ns P in casing C.
Now with reference to Fig. 3, t'ae floating piston 13 may contain an opening
13C
therethrough as well as a rupturable diaphragm member 13D at the inwardly
extending face 13B
of the floating p iston 13. The opening 13C is provided within the floating
piston I3 to permit
fluid pressure in the fluid within the fluid passageway FP of the conduit CT
to be applied to the
diaphragm 13D ~.o rupture same subsequent to activation of the apparatus 10 as
described below,
to permit subsequent introduction into the wellbore WB of the fluid within the
fluid passageway
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FP for subsequent treatment of the well through the perforations P, or any
other desired, and
known, purpose. r
Now refeorin,g to the embodiment shown in Figs. 5, 6 and 7, a plurality of
tandem, parallel
floating pistons 13 may be provided in a fluid injection apparatus 10 which
coatains companion
fluid chambers 2U and 201 separated by a chamber isolator 17. The shear pins
113 and 113 may
provided with se~>arate shear load or strength characteristics such that one
of the blow out plugs
1~ is ejected out she lowermost end of the apparatus 10 prior to breaking or
shearing of the other
pin 13l to subsequently eject the blowout plug 151 from the lowermost end of
the fluid chamber
201. They may also, of course, have the same shear load resulting in
simultaneous breaking.
20 Likewise, the ruFaure rating of the disk 13L' anw 13D~ are varied such that
one of the passageways
I3C is open before the other passageway 13C' is opened for sequential
introduction of the rluid
within the fluid passageway FP through the pistons 13, 13', the chambers 20,
20' Thence exteriorly
of the apparatus l0 through the respective lower ends. Accordingly! the fluid
withit. one of the
chambers 20, is caused to be introduced into the wellbore WB prior to
activation of the other of
15 the chambers 2G' and the second, parallel piston 131, as shown in Fig. 6.
Such embodiment of
the present invention would have application in the event that a polymer
composition is desired
to be prepared in-situ by means of monomer "A" being placed within fluid
chamber 20 and
monomer "B" becng placed in fluid chamber 20~ with requirement that monomer
"A" he deposited
within wellbore WB for a given time prior to introduction of monomer "B" in
chamber 20' into
20 the wellbore WB ac a subsequent, or delayed time.
Now, with reference to Fig. 8, they.°_ is shown an alternative
embodiment of the present
invention in whit h the fluid injection apparatus 10 actually is a part of the
conduit CT and is not
CA 02331473 2001-O1-19
provided at the lc,wermost end of the conduit C'f by threads 11 engaging the
apparatus 10 to the
lowermost end of tie conduit CT.
OPERATION
When it is desired to treat the wellbcre WB and/or the fractures F through the
perforations
P in the casing C , the apparatus IO is secured by threads 11 to the lowermost
end of the conduit
CT. Thereafter, the treatment tluid is introduced into the fluid chamber ?0 by
mean:. or the port
12C and the floatLng piston 13 moves to the p.~siti,~n as shown in Fig. 1. The
port 13C is plugged
by introduction of the plug 12D therethrough. Now, the apparatus :10, is run
into the wellbore
WB on the lowermost end of the conduit CT unusuch time as the approximate
lowermost end of
IO the apparatus 10 ~s parallel to the perforatic.-ns P. Now, pressure is
applied to the flu:;:. within the
conduit CT and the fluid passageway FP ~~~ be applied the upper face of the
piston 13A and
compressing the fluid within the fluid chaa:lber 20. As the pressure within
the chamber 20 is
increased, the shear value of the pins 13 a:~d 14 will be exceeded, causing
the pins 1:3 and 14 to
break and. thus, 3ischarge the blowout plug i5 through the lowermost end of
the apparatus 10.
1~ The treatment fluid within the fluid chamber 20 is discharged and the
discharge is continued
through continued application of pressure within the conduit CT such that the
floati:~;J piston I3
travels downwarclly within the fluid chamb~:r 10 until it no-goes by the
contact of the lower face
13B with the shoulder 12B of the piston seat sub 12A. Such position is as
shown in Fig. 2.
W'~en the embodiment of the invention is utilized as shown in Figs. 3 and 4,
c1P piston 13
20 is pumped to the position shown in Fig. 4 to positively discharge all of
the fluid from., within the
i~uid chamber 20. Thereafrer, fluid pressure within the conduit CT and the
fluid pas:;ageway FP
is continued to b~: increased until such time as the diaphragm 13D is
ruptured. Upon rupture of
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the diaphragm 1. D, fluid within the conduit CT may pass through the
passageway or opening 13C
within the interior ef the floating piston 13, thence through the outer open
end of the apparatus
for introduction into the wellbore WB, for spotting, circulation, and/or
recirculation, as the
occasion merits.
Now with reference to the embodiment of the invention shown in Figs. ~, 6, and
7,
separate treatmelu fluids are deposited and prepared as above, for each of
fluid chambers 20 and
20'. Pressure is applied to each of the floating pistons 13, 13', but the
shear strength of shear pin
13' being considerably more than that in shear pin 13 for plug 1~, the
floating piston I3 is
permitted to mo~~e to compress the fluid within chamber 20 to shearpin 13 and
remove plug I5,
10 thereby discharging the first fiuid within laid chamber 20. Pressure is
continued to be applied
within rl:° conduit CT fluid passageway FP against the uppermost end
13A' of the piston 13' to
cause same to move to the position as shov~t~ m Fig. 7, resulting in the
discharge of the second
treatment fluid within fluid chamber 201. 'rhea=after, the rupture disk
elements 13 J and 13D'
within each of the piston members 13 and 131 may be broken to permit fluid
within the fluid
passageway FP ~o pass through both of the fluid chambers 20, 201 and into the
wellbore WB.
The embodiment of the apparatus 10 shown in Fig. 8 provides for the interior
of the
conduit CT to be the fluid chamber 20 which is blocKed or isolated by means of
one floating piston
13 bridging the fluid chamber 20 and the fluid passageway FP in the conduit CT
thereabove. The
apparatus is activated and operated as for the embodiment as shown in Figs. 3
and u.
AlthougY~ the invention has been described in terms of speciiyed embodiments
which are
set forth in detail, it should be understood that this is by illustration only
and chat the invention
is not necessarily limited thereto, since alternative embodiments and
operating techniques will be
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come apparent to those skilled in the art in view of the disclosure.
Accordingly, modifications are
contemplated which can be made without departing from the spirit of the
described invention.
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