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.
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.
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, 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.
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 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 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 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 _g_ 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 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.