US2605847A

US2605847A - Wet plug for well pipes

Info

Publication number: US2605847A
Application number: US101041A
Authority: US
Inventors: Carl J Mccoy
Original assignee: Individual
Current assignee: Individual
Priority date: 1949-06-24
Filing date: 1949-06-24
Publication date: 1952-08-05
Anticipated expiration: 1969-08-05

Description

Aug. 5, 1952 c. J. M COY WET PLUG FOR WELL PIPES 2 SHEETSSHEET l Filed June 2 1949 li lil I 1 IVEN TOR. @994 a. MCCOJ ,QNCwA/EVS Aug. 5, 1952 ,c. J. MCCOY WET PLUG FOR WELL PIPES 2 SI-IEETS-SI-IEET 2 Filed June 24, 1949 M! a z m a m INVENTOR.

HTTOQNEVS' Patented Aug. 5, 1952 UNITED STATES. PATENT OFFICE I i 7 i 2,605,847; f

WET PLUG FOR WELL PIPES" V can J. McCoy, Orcutt, Calif.- Application June 24, 1949, Serial No."101;041

13 Claims. (01. 166-14) This invention relates to the art of producing petroleum from wells and is particularly directed to improvements in apparatus employed for removing eduction tubing fromjthe' well hole while the tubing is full of well fluid.

Conventional, pumping; apparatus for petroleum wells includes a pump at the lower end of the eduction tubing and a sucker rod which extends through the eduction tubing to the surface. The sucker rod is reciprocated within the tubing to actuate the pump for lifting the well fluid to the 'surfacerfIt is necessary from time to time towithdraw the eduction tubing from the well for the purpose of servicing or replacing the pump. [If the pumphas become sanded up during use or has been rendered inoperative for any reason the well fiuid may remain in the eduction tubing as it is withdrawn upwardly from the well hole.- As the eduction'tubing is withdrawn lengths thereof are disconnected section by sectionand stacked on end within the derrick. When the threaded connection between adjacent sections is broken oil within the lower part of the tubing may be forced out by gas and spread over the derrick floor and the working crew, thereby creating a fire hazard and making the task of withdrawingthe eduction tubingdifficult and unpleasant; I

Even after an upper section oi the eduction tubing has been disconnected and set aside, gas formerly dissolved within the well fluid may be released by the reduction in pressureon the well fluid and causethe well fluid within the lower portion of the eduction tubing -to surge by headsif To avoid undesirable surging and consequent drenching of the derrick floor with petroleum it has been the conventional practice to screw a conventional plug in the uppermost coupling of the lower portion of the eduction tubing as soon as an upper section is disconnected and removed. The operation of placing the plug I in position andscrewing it into the threads must be accomplished rapidly and effectively before a surge or head? occurs. If the plug is crossthreaded'or otherwise-inseourely attached before a surge occurs'the force of the well fluid against of threads and whichrequires only a minimum of time to place in position. Furthermore, I provide means for venting the gas pressure away while retaininggthe oil Within the eduction tubing. The danger of spraying petroleum over the derrick floor ;and working crew occasioned by surging within the lower part of the eduction tubing is therefore largely eliminated. The wet plug embodying my invention is attached to the upper end of each eduction tube section in turn forming a seal against escape of well fluid but permitting escape of gas. A vent valve is incorporated into the device which'is moved to closed the plug may disengage it and the operator may i be injured if the plu Should strike him. .This hazard connected with the operation of screwing the plug into position-often causes-the operator to attempt to hurry the operation unduly with the results that the plug is cross-threaded or is jammed in thef'coupling. I I I In accordance with my invention I provide a new and improved wet plug device which may readily be installed" without careful alignment position by the action of liquid moving upwardly within the'eduction tubing but is uneffected by gas pressure. Accordingly, the gaswithin the upper portion of the eduction tubing is vented away but when oil approaches thewet plug at the upper end-of the tubingthe gas venting valve is automatically closed to prevent escape of oil. Accordingly, it is the principal object of my invention to provide a new and improved form of wet-plug for use in connection with the with drawal of eduction tubing from a well hole.

Another object is to provide a device of this type: which automatically vents on gas within the tubing-but which prevents escape of oil.

Another object is to provide such a device which maybe readily and rapidly secured to the upper openend of the eduction tubing with a minimum of care-in alignment.

Other and more detailed objects and advane tag'es will appear hereinafter.

In the drawings: Figure 1 is a side elevation principally in 10ngitudinal section showing a preferred embodieduction tube for a well.

Figure 2' is a sectional plan view taken substantially on the lines 2-2 as shown in Figure 1.

Figure 3 is a partial sectional view showing a modified form of my invention.

Referring to the drawings the eduction tubing generally designated [0 extends into a well bore (not shown). The tubing may be formedof a plurality of tubular sections connected by threaded couplings, I I. Eachof the couplings is providedwith the usual internal pipe threads l2. As the eduction tubing 10 is raised from the well it. is unjointedfsection by section and the couplings l is commonly remain on the upper ends of the sections rather than the lower ends as the sections are set aside.

In accordance, with my. invention a wetplug assembly generally designated I3 is adapted to be inserted into the upper open end of the coupling II. The assembly I3 includes a body I4 having a downwardly extending conical skirt I5. The body is provided with a central opening I6 for slidable reception of the sleeve I1. The lower end of the sleeve I1 is provided with a flared portion I8 having a flange I9 at its extreme end. A resilient packing ring 20 is mounted on the flared portion I8 between the flange I9 and the lower end of the skirt I5. A series of annular serrated rings 2| is provided on the flared portion IS above the position of the sealing ring 20 and p a plurality of toothed rollers are rotatably mounted on the body I4 and arranged to mesh with the serrations 2 I. The teeth of these rollers 22 engage the threads I2 within the upper end of the coupling II and the action of the serrations 2I is to prevent rotation of the toothed rollers 22. The rollers 22 may each be provided with integral laterally extending trunnions 23 received within horizontal recesses 24 provided on the skirt I of the body It. Each of the toothed rollers 22 is therefore capable of rotating about the axis of the trunnions, 23 and alsom ay have limited radial movement as the trunnions slide within the transverse recesses 24-. If desired, spring means (not shown) may be employed for normally urging the rollers 22 to move, in a radially outward direction. V V

A detent ring :25 may be provided on the sleeve I? if .desi-re dpand one or more spring urged balls 26 may enter the detent rin 25 to maintain the sleeve I! in its raised position. A coupling collar 21 connects the upper end of the sleeve IT to the valve body 28. A valve member 29' is slidably mounted within the central axial opening 33 in the valve body 28. The valve member 29 is provided with'a reduced portion 3| between its opposed ends so that in one position of the valvemember 29 the

body ports

32 and 33 are placed in communication, and in another position of the; valve member 29 the ports are isolated. Thus when the valve member 23 is in the position. shown Figure 1, gas within the sleeve Il may pass upwardly through the port 32 into the bore of the valve body 28. The gas may then escape throughrvent ports 33 to the atmosphere. I If the valve member 29 is raised so that the lower cylindrical portion thereof closes the innerends of the ports 32, gas within the sleeve I'I cannot-reach the central bore 30 and hence cannot escape through the vent ports 33.

The "valve member 29 or'valve head may be secured by any convenient means to an actuating rod or tube 34 which extends axially into the interior of the sleeve IT. A hollow float 35 is secured to the lower end of the tube 34 by any convenient means such as,rfor example, the threads 38 and lock nut 31. From this description it will be understood that vertical movement of the float 35 within the sleeve II acts 7 4 a side port 34a and the valve member may have a bore 2% therethrough.

In the operation of the device the wet plug assembly I3 is inserted into the upper end of the coupling II as soon as the pipe section formerly threaded into the threads I2 has been disconnected and set aside. When the assembly I3 is installed in position the sleeve I1 is in its lower-position with the shoulder 40 on the coupling collar 21 in engagement with the shoulder H defined by the upper surface of the body I4. In this position the flared portion I3 at the lower end of the sleeve I'I extends downwardly below the lower end of the skirt I5 so that the resilient sealing ring 20 contracts radially. The assembly I3 may be inserted quickly and easily into the upper end of the coupling II without any alignment of threads or careful manipulation. When the shoulder 42 on the underside of the body I l engages the upper end of the coupling. IL: the ember grasps the handle 39 and raises the sleeve I1 upwardly. This action forces the toothed rollers" 22: into engagement with the threads I2" and. into engagement with the annular serrations .2I, abruptly locking the assembly I3 inposition within the coupling II-. Formation. gas formerly. dissolved in the well fluid and released therefrom. by relaxation of pressure on the well fluid is vented out through the

ports

32 and 33 so long as the float stremains in its lower position. In the event of a surge or head? of oil within the eduction tubing I0, the liquid oil raises the float 35 against the action of. gravity and moves the valve head 29 to shut oii" the vent ports before any appreciable quantity of oil. can escape through port 33. Flooding ofthe derrick floor andfcrew with oil is thereby prevented. When the surge or head subsides the float 35,-desce'nds by gravity and again acts to vent gas to theatmosphere. The assembly I3 is not blown out of position by the pressure of the oil and gassinoe the toothed rollers 22 prevent upward movement 'of the as sembly I3. I'he seal ring 20 prevents escape of well fluid upwardlyalong the threads I2 in any appreciable quantity.

After the wet plug assembly I3 has been placed in operative position, and after the sleeve IT has been raised to lock it against displacement, the well crewraises the eduction tubing Ill in the normal conventional manner. This ordinarily entails the use of an elevator which engages under thelower shoulder 43 of the coupling -II. The wet plug assembly remains in the coupling II as it is raised upwardly within the derrick and until the next succeeding joint in the eduction tubing is disconnected. At the time-of such subsequent disconnection the float 35. acts'to vent thespace within the sleeve I! and within the upper sect-ionlof the eduction tubing so that well fluid is not retained within the .upper section by suction pressure. As soon as the lower threaded coupling is disconnected, another wet plug assembly which is a duplicate of that shown and described is inserted into the lower coupling. Theassembly I3 on the upper end of the pipe section just disconnected is then removed from its-operative position and lowered to the derrick floor'by means of a line attached to the bail M. The bail 44 may conveniently be attached to the body by means of the pivot pins 45.

As the eduction tubingisv raised anddisconnected section by section the two wet plug assemblies I3 are used alternately so that the upper nd of the eduction tubing is kept closed except for the very short interval after the threaded connection is broken and before the wet plug assembly I3 is installed in position. The construction of the vent valve assembly including the

parts

28 and 29 is such that the valve is substantially balanced and the pressure of the gas within the sleeve I! has no effect on the opening and closing of the valve.

In the modified form of my invention shown in Figure 3a plurality of radially slidable dogs 50 replace the toothed wheels 22. Each of these dogs is received within a recess 5| provided on the skirt I561. The extending end 52 of each of the dogs is serrated to engage the teeth [2 in the coupling II and the inner end 53 of each dog is tapered to rest against the flared portion I8a of the sleeve Ila. The sealing ring 29a is positioned on the lower end of the flared portion I81; and is supported by the annular flange ISa. Retraoting springs 54 may be provided for each of the dogs 50 so that the serrated faceof the dog is moved out of engagement with the threads I2 when the sleeve Ila is lowered with respect to the body [4a. The operation of this form of my invention is substantially the same as that previously described in connection with Figures land 2. In both of these forms of my invention the pressure of the gas and well fluid within the eduction tube tends to hold the wet plug device in position, and therefore the greater the pressure the tighter is the plug secured.

Having fully described my invention, it is to be understood that I do not wish to be limited to the details herein set forth, but my invention is of the full scope of the appended claims.

I claim:

1. In a wet plug assembly for insertion into a threaded coupling on the upper end of an eduction pipe in a well, the combination of a body having a skirt thereof adapted to extend into the threaded coupling, a sleeve slidably mounted within the body and provided with a flared portion projecting below said body, rotary locking elements cooperating with the flared portion and adapted upon relative axial movement of the skirt and sleeve to engage the threads of the coupling, a resilient sealing ring encircling a portion of the sleeve, said sealing ring being expandible into engagement with said threads upon relative movement of the body and sleeve in a direction to actuate the locking elements.

2. A plug structure for temporary placement in the internally threaded upper end of eduction tubing, involving: a body member adapted to engage the upper end of an eduction tube and including a skirt depending into the internally threaded end thereof; a sleeve slidably mounted within said body member and terminating in a flared end projecting below the skirt of said body member; an annular seal ring interposed between the lower extremities of said skirt and sleeve and adapted to expand radially on upward movement of said sleeve in said body member to seal against said internal threads; and toothed radially movable locking members carried by said body member and engageable by the flared portion of said sleeve to interlock with said internal threads of the eduction tube on upward movement of said sleeve in said body member.

3. A plug structure for temporary placement in the internally threaded upper end of eduction tubing, involving: a body member adapted to engage the upper end of an eduction tube and including a skirt depending "into the internally threaded endthereof;' a sleeve'slidablyxmounted within said body-member and terminating in -a flared end projecting below the skirt of. saidbody member; an annular seal? ring-interposed between the lower extremities .:of said skirt and sleeve and adapted toexpand radially on upupper extremity of"said =sleeve for. ventin as from said eduction itubing; and a float member suspended within said sleeve for closing said valve on rise of liquid into said sleeve.

4. A.plug structure'a's' set forth in claim 2 wherein said locking members are toothed wheels and the flared portion of said sleeve is equipped with teeth to engage said wheels.

5. A plug structure as set forth in claim 2, wherein: said locking members are radially guided and slidable dogs having teeth in their radially outer ends, and their radially inner ends being engageable by the flared portion of said sleeve.

6. A plug structure as set forth in claim 3 wherein: said locking members are toothed wheels and the flared portion of said sleeve is equipped with teeth to engage said wheels.

7. A plug structure as set forth in claim 3 wherein: said locking members are radially guided and slidable dogs having teeth in their radially outer ends, and their radially inner ends being engageable by the flared portion of said sleeve.

8. In a device of the class described for closing the upper internally threaded end of an eduction pipe in a well, the combination of a body member, a sleeve member slidably mounted with respect to the body member, locking elements carried on the body member and movable into engagement with the internally threaded element at the upper end of the eduction pipe, a seal ring on the sleeve member adapted to engage within the internally threaded element, operating means on said sleeve member for moving said locking elements radially and expanding said seal ring into operative position upon relative axial movementof said sleeve and body members, a vent valve on one of said members, and a float operativelyconnected to close the valve in the event that well fluid should rise in the eduction pipe.

9. In a device of the class described for closing the upper internally threaded end of an tive axial movement of said sleeve and body members.

10. A device as set forth in claim 8, wherein:

adapted to forcefti'd wheels: to: fint'ermesh with. 1

the internal screw threads of said eductio'n, pipe. 1 2. Adeviceaszsetidrth in claim 8, wherein: said lo'cking 'elementsi are dogs. supported f'cr radially sli'dable movement by said bodymember, said dogs havingmteetlr at-their radially outer ends for meshing. with the'internal screw threads of said eduotion pipe, and whereby said operating: means includes a tapered portion engaging the radially inner ends ofjsaid dogs;

13. A device as set forth in claim 9, wherein: said locking elements are dogs supported for radially slidable movement by said body member, said dogs having teeth at their radially outer ends for meshing withrthe internal screw threads of said eduction pipe, and whereby said operating means includes a tapered portion engaging the radially inner'ends of said dogs.

CARL J. MCCOY.

REFERENCES CITEEI The following references are of record, in the file of this patent: 1 4

UNITED STATES PATENTS Number Name Date 1,529,607 Owen .'Mar. 10, 1925 1,616,973 MacClatchie Feb. 8, 1927 1,835,418 McHardy Dec. 8, 1931 2,092,843 Henderson Sept. 14, 1937 2,208,181 Eggleston July 16, 1940