US2893493A - Traveling seal and paraffin scraper device - Google Patents

Description

1 July?, 1959 J. l. coPAs TRAVELING SEAL AND PARAFFIN SCRAPER DEVICE Filed March 17, 1955 2 Sheets-Sheet 1 dmes I. Caoa:

INVEN 0R July 7, 1959 .1.1. coPAs 2,893,493 TRAVELING SEAL AND PARAFFIN scRAPER DEvIE Filed uarcn 17, 1955 2 sheets-sheet 2 Jia, 7/

f'- 22 www 25 B ad E uaMf/.k I 524 23 Arm/wins 2,893,493 Patented July 7, 1959 rTRAVEL-ING SEAL AND PARAFFIN SCRAPER f f DEVICE James 'I. Copas, lOklahoma City, Okla. .Application February 17, 1955, Serial N0. 488,848 l v*6 Claims. (Cl. 16E- 170) is utilized to lift well fluids upwardly within a well tubing, it has been the usual practice toinsert a sealing device, generally known as a traveling rabbit or piston,

In gas lift operations wherein an auxiliary lifting gas `into the upper end ofthe tubing to permit it to fall downwardlvthrough the fluid to be lifted to a point i `above the elevation at which the lifting gas is introduced.

Such device functions to seal with the wall of the tubing the device is lifted to the surface. The primary pur- ,pose of the device is to separate or seal off the lifting gas -fromthefwell fluid being lifted to prevent said gas from channeling upwardly through said fluid which results in lessening the eflciency of the lifting operation.

Normally the device is dropped into position just prior to the injection or introduction of the lifting gas into the tubing and is moved upwardly upon the subsequent introduction of said lifting gas.

It is one object of the invention to provide an irnproved device of the piston type for sealing olf between the well fluid and the lifting gas which is extremely simple and inexpensive in construction, which has an ample by-pass therethrough on its downstroke to assure proper llowering into position and which is extremely effective in its sealing action on the upstroke, whereby the device not only functions to sealingly separate the lifting gas from the well iiuids but also acts as a parain scraper to clean the bore of the well tubing.

An important object is to provide an improved sealing device having a sealing element mounted thereon, together with a sleeve type by-pass valve which is automatically actuated in accordance with the direction of movement of the device through the well pipe; said valve being opened upon the downstroke or downward movement of the device and being automatically moved to a closed position upon the upstroke.

A further object is to provide a device of the character described wherein control of the sleeve valve is effected by means of a slidably mounted sealing element which element is moved by the fluid load thereof `or by the frictional engagement of the element with the pipe, whereby openingl and closing of the valve is controlled in accordance with the direction offmovement of the device through the well pipe.

The construction designed'to carry out the invention Will be hereinafter described together With other features thereof.

The invention will be more readily understood from a reading of the following specication and by reference to the accompanying drawings forming a part thereof,

wherein an exam-pleof the invention is shown and illustrating a device, constructed in accordance with the therein.

invention, disposed in a catcher at the upper end of said tubing;

Figure 2 is a longitudinal, sectional view of the corn- .bined sealing and paraffin scraper deviceand `illustrating .d the parts thereof in their respective positions While the device is moving downwardly through the tubing;

Figure 3 is a similar view with theh parts in their respective positions `during upward travel of the device; Figure 4 is a horizontal, cross-sectional View taken on the line 4-4 of Figure l; and

Figure 5 is a horizontal, cross-sectional view taken lon the line 5 5 of Figure 2.

In the drawings, the numeral 10 designates a well casing through which a well tubing 11 extends. As is well known, the annular space between the casing and the tubing is sealed oif by a suitable packing 12 within a casinghead 13. The well fluids which are being produced flow upwardly through the well tubing and are discharged therefrom to an outlet line 14 having a suitable control valve 15 mounted therein. When well fluids are produced by means of gas lift it is the usual practice to control the admission of the auxiliary lifting gas intothe tubing by means of a suitable flow valve (not shown) which is disposed at some point in the lower portion of the4 tubing below the normal well fluid level Sufficient time is permitted to elapse between intermittent operation of the ow valve so that well fluids may enter the tubing string and rise upwardly therein `to a predetermined level. `Upon the admission of the auxiliary lifting gas, said lgas functions to lift the well 'liquids upwardly within the tubing string to effect their l to channel upwardly through the well iluids whereby thegas lifting operation is interfered with and to overcome this objection it has become the general practice to lower a sealing device downwardly through the well iiuids to some point just above the point of admission of the lifting gas. Upon introduction of the lifting gas said device seals with the wall of the tubing and separates the gas from the liquid which is being lifted and in this manner the full eiect of the lifting gas is obtained. It has also been found that each head of uid usually results in the deposit of paraffin upon the Wall of the tubing, usually toward the upper end thereof.

The present invention provides an improved device which may be termed a combination sealing and parain scraper device and which accomplishes the separation of the lifting gas from the fluid being lifted While at the same time removing any paraffin deposits which may have accumulated on the wall of the tubing.

The device of this invention is generally indicated by the letter A and is shown in detail in Figures 2 to 5. The device includes a centraltubular support or mandrel 20 which has an axial bore 21 extending entirely therethrough. An enlarged collar 22 is threaded onto the lower end of the support or mandrel and is formed with an axial opening 23 which communicates with the bore 21 of said support. A choke ring 24 is adapted to be supported upon an internal shoulder provided within the collar 22 and this choke has an opening 25 of predetermined size which functions to determine the rate of downward movement of the assembly through the well fluids in the tubing, as will be hereinafter explained.

The upper end of the support or mandrel 20 has a suitable fishing neck 26 welded or otherwise secured thereto and below the fishing neck said support is formed with a pair of diametrically opposed slots 27. A transversely extending pin Z8 has its ends projecting through the opposed slots 27 with said ends being secured within the wall of a tubular sleeve valve 29. As is clearly shown in Figure 2, the sleeve valve surrounds the upper portion of the support or mandrel 20 and is movable longitudinally thereon within the limit of the length of the i slots 27. The sleeve valve is formed with exhaust ports drel or support and the annular space or area exteriorly of said mandrel. When the sleeve valve is in a lowered l positionl relative to the mandrel, as shown in Figure 3, the

ports 30 move belowv the slots 27and are in 'effect closed to shut off communication betweenrthe bore 21 of said mandrel and the area exteriorly of the device.

A valve actuating member A, whichis shown as comprising a sealing element, is mounted to slide on the mandrel 20 and may be of any suitable construction. The sealing element is illustrated as'constructed of an elastic body 31 having annular sealing rings 33, which Ibody is moulded or secured to a metallic tube 32. As will be explained, the member A is subjected to fluid load or has the periphery of the rings 33 in frictional engagement with the tubing bore so that movement of the mandrel 20 relative to the member A results in opening and closing the sleeve valve. Although the sealing element which is illustrated has been found satisfactory, the invention is not to be limited to this exact construction and other types of actuating members may be employed.

The actuating member A is-conned between the sleeve valve29 and a retainer ring 34, and a coil spring 35 `which encircles the support or mandrel has its upper end engaging the Aring 34. The lower end of the spring 35 contacts a ring 36 which engages thel upper end of a piston element S1. K The piston element is preferably in y lthe form of an elongate sealing means comprising a body portion having annular sealing rings 33ay similar to ythe rings 33 of the upper member A; however, since the piston primarily functions to raise the device when pressure is introduced therebelow, it is evident that -the rings 33 need not engage the wall of Vthe pipe because so long as said rings are in close proximity to the wall, suicient restriction is created to cause the lifting action to be carried out. To perform the paraffin scraping function it ris desirable that the periphery of the lring sealingly engage the pipe wall. The lower end of the piston S1rests upon the upper end of the collar 22 which is secured to the lower end of the mandrel and upon movement of the device, said piston substantially prevents the passage of lifting gas upwardly past the device.

In the operation of the device A, said device is normally retained within a tubular housing 40 which is preferablyV connected to the upper end of the tubing string 11 as illustrated in Figure l and-is'held therein by a retractable plunger 41 which upon retraction will release the device A to permit it to fall downwardly through the well tubing. v

When the device A is dropped downwardly through the tubing 11 the parts are in the position shown in Figure 2l In such position the spring 35 is holding the actuating member A upwardly withY respect to the piston element' S1 while the spring 31a is maintaining the sleeve valve 29 in its lowest positionwith respect to the support or mandrel. It is pointed out that if the rings 33 of the element, whichforms the actuating member are inengagement with the wa-ll of the tubing the frictional drag of the rings on the tubing wall assist in maintaining'the valve open yduring downwardmovement Vof the device. The opening 25 through the choke ring 24 controls the rate of descent of .the device `and it is evident that by changing the size of the opening 25 the speed of downward travel of the device `as it falls through the liquid in the well tubing may be controlled.

4 it strikes av stop or shoulder 42 (Figure 1)-which is provided within the bore of the tubing at an elevation which is preferably just above the point of admission of the lifting gas into said tubing. The device remains at this 5 position until lifting gas is admitted or introduced into the tubing and said gas acts against the piston S1 to move the sealing members 33 of'said sealing element into sealing engagement with the wall of the tubingg'thereafter the device A as well as the Vwell liquids thereabove begin to moveupwardly within the tubing string. As soon as an upward movement ofthe device begins, the lfrictional resistance or drag of the rings 33 of the actuating member A las well as the fluid load which is acting upon said rings 33 to urge the same into tight contact with the wall of the tubing, tends to cause the piston S1 to be moved upwardly with respect to actuating member A, such movement being permitted by .collapse of the 'spring 35. The parts lthus moveto the position shown in 'Figure 3 so thatthe piston S1 is moved closer to `the actuating member, with said actuating member sliding f downwardly 'on the mandrel. At the, sa'mel timethe coil spring 31a, which is constantly: acting upon the sleeve valve29 tourgesaid valve tov its lowermost position moves Isaid valve downwardly on the mandrel, whereby *A the exhaust ports 30which permitted aj free lby-pass of fluid 'during lowering, are closed, `and thereafter the device A aswell as the well fluids thereabove are lifted'to thesurface. j l y 'It is evident that the iiuid load `acting on the rings 33 3Q of the actuating member maintains said'rings in frictional contact with the wall ofthe bore whilethepressure of the l.lifting gas below Vthedevice maintains the rings ofk the piston S1 in tight sealing contact with said wall. Thereafter,` as the well fluids' are lifted and the device D moves 35;Y upward-ly through the tubing, the walls of the tubing are Hscraped or, cleaned of 'any paraffin which might have accumulated Aduring lifting of the preceding head of uid. "The devicefunctions to separate and substantially seal off the well fluids from'the ilifting'gas and at' the same 40 time provides for the removal of any paraffin which may be present on the wall of the'tubingtbore,

When the device reaches the surface it moves past the spring-pressed plunger v41 and into the housing 40 where uit is retained until the next operation. It is ,pointed out 4 -.that the device is extremely' simple in construction and provides the sleeve valve control which' permits large exhaust ports'to be provided, whereby rapid lowering, of the device through the well fluid may be accomplished `while at the Vsame time providing a tight shut-off of uid 56 during the upward'travel. kAttention is'called to the fact that both' the piston elementSl and the actuating member lA are shown as sli'dable upon the mandrel in which event the spring 35 is necessary to holdY these elements apart however, if thepiston is secured to the mandrel the spring 35 may be Vomitted andin such event the frictional drag on rings 33. of the member A Vor, the pressure or load 'acting thereagainst as the device moves lthrough the pipe will effect the sliding movement of the member A on the mandrel to open and close the valve. 60" The foregoing disclosure and description of the inven- -.tion is illustrative and 'explanatory thereof, and various changes in the size, shape' and materials, as well as in the details of the illustrated construction may be made, within the scope of the appended'claims, without departing from the spirit of the invention.

What I claim is: v l. A combined sealing and paraffin scraper device adapted to be' inserted within a well pipeandv including, a tubular mandrel having an external abutment on its lower end and 'a radially-directedopening at its upper end, the upper end of the "mandrel being closed, a piston I element supported on the abutment, an annular actuatfingmember slidable on the mandrel arid spaced above said'pist'on element, said'member ihaving means engage- The deviceA falls downwardly through the tubing until able with the wall of the pipe in which the device is disposed for creating a frictional drag, a sleeve valve encircling the mandrel above the actuating member element and engageable by said actuating member, said sleeve valve co-acting with the opening in the mandrel to open and close the same in accordance with the position of the valve on the mandrel, and stop means for limiting the upward movement of both the sleeve valve and actuating member on the mandrel, the sleeve valve being in open position when in its uppermost position on the mandrel, the piston element being acted upon by pressure from below, a higher pressure below the piston element moving the device upwardly in the well pipe and causing the piston element and mandrel to be moved upwardly relative to the actuating member and sleeve valve to etfect a downward movement of the sleeve valve to close the opening in the mandrel.

2. A device as set forth in claim 1, wherein the piston element includes annular sealing members which are urged into contact with the wall of the well pipe by the pressure acting thereagainst during upward movement of the device within the well pipe, whereby said members remove parain accumulation from the wall of the pipe.

3. A device as set forth in claim 1, together with a choke means mounted in the lower end of the tubular mandrel for controlling the rate of descent of the device when the same is dropped through well fluids in the well pipe. v

4. A sealing device adapted to be lowered into a well pipe for sealing the bore thereof, including, a tubular mandrel having a closed upper end, a piston element mounted on the mandrel, an annular memfber slidably mounted on the mandrel above the piston, resilient means for normally urging the annular member away from the piston element, whereby the annular member normally assumes a first position spaced from the piston, said annular member Ibeing movable against the pressure of the resilient means toward the piston to a second position which locates said member closer to said piston, valve means mounted on the mandrel and having a part engageable by the upper end of the annular member, said valve means being movable relative to the mandrel and adapted to control communication between the lbore of the mandrel and the area exteorly thereof above the annular member, said part on said valve means coacting with the annular member so that the valve means is open when the annular member is in its first position spaced from the piston and said means is closed when the annular 6 member is moved toward the piston to its second position closer to said piston.

5. A sealing device as set forth in claim 4 wherein the resilient means normally holds the annular member spaced from the piston so that said annular member coacts with the part on the valve means to maintain said valve means open and also wherein the pressure below the device which acts upon the piston moves said piston toward the annular member to elect a closing ofthe valve means.

6. A sealing device adapted to be moved through the bore of a well pipe including, a support having a closed upper end and also having a lluid bypass passage therethrough, valve means slidable on the support for controlling ow through said .'bypass, an actuating member slidable on the support lbelow the valve means and engageable therewith, said member having means frictionally engaging the wall of the pipe to retard movement of the actuating member through the pipe, a piston element mounted on the lower end of the support and exposed to the pressure below the device, and a spring means disposed between the actuating member and the piston element and normally urging these parts away from each other to a first position, the actuating member and element being movable toward the piston element to a second position which locates said member closer to said element, the actuating member located on the mandrel to maintain the valve means in open position when the member and piston are spaced farthest from each other in said rst position, said actuating memfber and piston element being moved toward each other to said second position by the pressure acting upon the piston and moving said piston and support upwardly relative to the actuating member, movement of the piston element toward the actuating member to said second position permitting the valve means to close the bypass passage through the support.

References Cited in the le of this patent UNITED STATES PATENTS 1,819,994 Claytor Aug. 18, 1931 1,922,396 Rieker Aug. 15, 1933 1,989,035 Blum Jan. 22, 1935 2,058,825 Rallet et al. Oct. 27, 1936 2,184,393 Luccous Dec. 26, 1939 2,674,201 Talbott Apr. 6, 1954 2,802,535 Taylor Aug. 13, 1957

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