US2163976A - Flow preventer for oil wells - Google Patents

Description

June 27, 1939. w K. EDWARDS ET AL FLOW PREVENTER FOR OIL WELLS Filed Jan. 22, 1958 2 Sheefs-Sheet l v June 27, 1939. w. K. EDWARDS ET AL 2,163,976

FLOW PREVENTER FOR OIL WELLS 2 Sheets-Sheet 2 of a v, 1 w 1 m ":1 21 g 5 5 m W% a a M m i g 4 H Z w .,w TL w Patented June 27, 1939 UNITED STATES PATENT OFFICE' 2,183,976 FLOW PREVENTER FOR OIL WELLS William K. Edwards, Big Spring, and Orland Thompson, Wickett, Tex.

Application January 22, 1938, Serial No. 186,456 10 Claims. (Cl. 166-13) This invention relates to devices of that type a pump down plug embodying the invention is which are pumped down into an oil well for illustrated. preventing the how of oil upwardly through the In the drawings: well tubing while certain repairs or replacements Figure 1 shows the invention, partly in vertical of the tubing are being made, or for any other section and partly in elevation, with the exreason it is found necessary to withdraw the well panding cone for the plug withdrawn,

tubing from an oil well, without permitting the Figure 2 is a view similar to Figure l, but

oil to escape from the well. showing the parts in a different position; that is,

Such devices are known in the oil well art as with the rubber packer and slips expanded for pump down plugs or flow preventers, and the holding the plug in position in the well; 10' present invention has to do with certain impor- Figures 3 and 4 illustrate the device in two tant improvements in such devices. separate parts, with the mandrel and packer parts The withdrawal from the well of the tubing, in section, and the valve and valve stem parts in for repairs or otherwise, renders it necessary to elevation; temporarily stop the flow of oil from below Figure 5 is a Section on the e of while such repairs or replacements of the tubing ure 3;

sections are being made, and while devices of Figure 6 is a Se i n 0 the line this general character have been heretofore cone I structed, so far as applicants are aware,they have Figure '7 is a section on the line 1--'| of Fi not operated with that certainty which is necesli e and d sary to insure the complete cutting off of the oil Figure 3 is a Section n the e F ure from the well, eithe he th tubing i with- The mandrel I, shown in elevation in Figures 1 drawn or there is a leakage through the tubing. and 2, and in Section in Figures 3 and 4, is hollow The present invention is devised for the purand the upp Portion thereof is e a y pose of insuring more certainty of the stoppage threaded and is surrounded by a rubber 3 which 2 f the flo by th pump-down lu nd moreis held in position between rings 6 and 1, threadover, to enable the well operator to remove the d to t man ehwhile a cap 2 is threaded to plug when desired, the extreme upper end portion of the mandrel A further and very important bj t of th and provided with apertures 32 for conveying cirpresent improvements, however, resides in a t s liquid o th terior of the mandrel. 30 mean for flushing th ll through th p p- The lower portion of the mandrel is provided down plug or flow r nt r, as sometimes after externally with threads and receives a lower rubthe plug has been pumped or forced to the bottom 4, Whose lower end is Secured in a ring of the tubing it has been found necessary to threaded t0 the mandrel, the pp P t o o 35 pump or cir ulat fl id th u h it, i order t the rubber 4 being herein shown as secured with- 35 free the tubing which may be obstructed or sandin an annular ec s in a tapering enlar locked, with a view t aeeemphshmg t pur- I! of the mandrel. A packer sleeve l6 of rubber pose applicants provide nd r th present i or other soft material, surrounds the mandrel vention a hollow mandrel in the flow preventer and i5 D Q With a longitudinal bo e f tt ng which contains a valve stem having thereon a Over the enlarged tepeling pertion O the 4 valve which is forced to its seat in the lower pormandr and extendmg upwardly therefrom a mm t the plug by a spring The tension of this substantial distance. The upper end of the rubber packer I6 is connected to a ring Ilia which s rm ma be so re ulated that while it will rgsistgthe Zpemng of valve under the pres surrounds the mandrel and slides thereon. A ta- Sures which force the plug down into the well, pered sleeve l8 surrounding the mandrel is con- 5 the spring will yield when a higher pressure is nected at its lower end portion with the ring lea, and extending upwardly from the tapered portion apphed tqthe mud for t purpose of permlttmg of the sleeve a cylindrical part thereof is provided circulamon the field through the Valve at opposite sides with diametrical slots lBb, the

131115 when extreme upper extension of the cylindrical portion 50 The foreemng, and other Important and of the sleeve I8 terminating in a ring l8c, the uable Obje t d advantages of he invention sleeve, its cylindrical extension and terminal ring will be more fully understood from the following being free to slide for a limited distance upon detailed description, when considered in connecthe exterior of the mandrel, for a reason which tion with the accompanying drawings, in which will be hereinafter explained. 5'5

Surrounding the sleeve l8 are a plurality of slips 20 which are herein shownas integrally formed with a collar 2i, the slips being separated from each other by slots, as shown, and leaf springs 22 extend from the collar 2| and have their outer, end portions bearing against the slips to normally hold the latter contracted and out of gripping engagement with the interior of the well tubing, which latter is indicated by the numeral 50. The slips 20 are, as usual, formed with annular teeth as shown in order that they may when properly spread, grippingly engage the interior of the tubing so as to prevent the flow preventer from being blown outwardly by the pressure within the well, after the pressure from above has been dimin- Ihe interiorwalls of the slips are tapered as shown, from a large bore at the lower end to a small bore at the upper portion, as will be clear from the drawings, such tapering interior surface of the slips causing, through engagement with the tapered exterior surface of the sleeve l8, when the latter moves upwardly relatively to the slips, due to the pressure from below, a spreading movement of the slips outwardly whereby they are made to engage the interior of the well tubing to thereby arrest outward movement of the flow preventer as an entirety. When the pressure from the well below is less than the pressure from above, due to the pumping of the fluid downwardly, the slips will be out of wedging engagement with the surface of the sleeve l8, and the springs 22 will effect a contraction of the slips, thereby leaving the flow preventer free for movement in a downward direction. This occurs while the pump is operating to force the fluid against the flow preventer to cause it to move downwardly in the well to that point where it is desired to shut off the well flow from the tubing.

When the parts are as shown in Figure 1 of the drawings, the mandrel with its tapered portion I2 is withdrawn a slight distance below the packer sleeve l6 and the tapering sleeve I8 is in lowered position, out of wedging engagement with the slips 20 so that both the packer sleeve and slips are withdrawn inwardly, and out of contact with the interior of the well tubing. This is the position that the parts assume when the plug or flow arrester is being pumped down into the well by the hydrostatic pressure effected by the pump. In the drawings we have shown of the pumping fluid lshed, or stopped.

the parts of the pump down plug in Figure 2 as in that position which they assume when the hydrostatic pressure from above is diminished or entirely suspended, whereby the pressure of the oil from below will the packer l6 against the wall of the well and at the same time the tapered sleeve will spread the slips 20 outwardly against, and in gripping engagement with, the well tubing so that the plug is prevented from moving outwardly and the packing l6 effects a tight joint between the well and plug to prevent outward escape of the oil.

As a means for effecting a circulation of the fluid through the pump down plug we have, under this invention, provided a hollow mandrel, and sliding interiorly thereof, as shown in Figures 3 and 4, a valve stem is provided. This valve stem is made in two parts, 21 and 28, the part 2! being at its lower end provided with a bore which receives the upper end portion of the section 23; as shown in Figure 4. A pin 49 extends transversely through an aperture in the lower part 28 of the valve stem, and acts as a limiting means against relative movement of the two portions of the stem, in a direction towards each other. The telescopic, sliding connection between the two members of the valve stem, however, permits relative movement of these the lower end portion of the mandrel,

valve with ports 3| for the exit of water of circulation. The telescopic, sliding connection or-slip joint between the two members of the valve stem is for the purpose of permitting the valve to be forced outward against the tension of the spring to permit the fluid to without affecting or mov- A thimble 34 is externally threaded to engage an internal thread in the lower portion of the member 33, said thimble being provided with a central bore and having apertures I [la in the lower portion thereof. A spiral spring 30 is located in the member 33 and confined between the lower face of the valve and the thimble 34. The latter serves as a. tension of the spring 30, and hence, for determining by such tension the hydrostatic pressure which the valve will resist before opening to permit circulation of the fluid.

The upper portion 21 of the valve stem is provlded with an enlargement or shoulder 38, and at a suitable distance therebelow, with a key 25, extending transversely through a slot in the stem. This key passes through diametrical guide slots in the mandrel I, the upward extension of the sleeve l8, and the slips 20.

The upper end portion of the stem part 21 is externally threaded to receive an internal and externally threaded cap 35. A sleeve 26 is shown as in threaded engagement with the external thread of this cap. .This sleeve is the size of the average pumping rod and is for the purpose of fishing the plug, when necessary to remove it, the diameter of the sleeve conforming to the tubing slips, or fishing tool, that is in common use. 26 may be and preferably is or some soft metal, and being threaded to the cap 35, it may be broken loose from the plug by upward pull on the line, in case the plug should be so stuck in the well that it would be impossible to pull the same, in which event, as will be obvious, the internal threads of soft or Babbitt metal in the sleeve 20 would strip.

Preferably, and as herein shown, the packer I6 is lined interiorly with a plurality of strips 48, which act as a reinforcing liner for the packer, and delay the wearing out of the packer through contact with the tapering portion l 2 of the mandrel, after repeated use of the plug.

It will be observed that during the operation of the oil pressure from the well the swab rubber 4 acts as a piston and effectively permits the pressure to not only spread the slips against the tubing to arrest movement of the flow preventer, but additionally, will effect the spreading of the packer sleeve l6 when the oil pressure from the well predominates over the pressure from the eifects an upward movement of the mandrel, thereby causing the tapering portion I2 to spread the packer l6 and thus effecting an absolutely liquid-tight joint, preventing any flow of oil beyond the flow preventer. Also, it is apparent that when the plug is being forced downward into the well the upper swab rubber 3 is that element of the plug upon which the pump pressure acts to force the plug downward into the well, preliminary to the release of pressure from above, under which circumstances the well pressure predominates.

When it is desired to circulate fluid through the plug, the pressure from the pump is simply increased to that point where it will overcome the resistance of the spring 30, thus forcing open the valve 29 and permitting the liquid to circulate.

Unless the pressure from above is sufficient to open the valve during the normal operation of the plug down into the well, the valve remains closed, thus permitting the plug to be moved downwardly to that point where it is desired to cut off the flow of the oil. It is common practice in well tubing to have a pin welded through the bottom of the'tubing to from going out into the well, and this pin will arrest the plug of the present invention when it reaches the bottom of the well, if it is ever forced down that far.

When it is desired to remove the plug from the well, fishing means; such as the sleeve 28, are threaded to the cap 35, or upperportion of the valve stem, which latter is pulled upward. Preliminary to this operation it is usual with this device to first jar it down slightly, thus giving the slips a chance to release from gripping engagement with the interior of the tubing, then upon an upward pull being applied to the valve stem, the key 25 will move upwardly in the slots in the mandrel, slip expander sleeve, and slips; and will lift the slips and packer up to the bottom face of the sleeve 1 attached to the swab rubber, this action freeing the plug from engagement with the well tubing. A further movement of the valve stem upward will cause engagement between the shoulder or enlargement 3B and the upper interior terminal wall of the cap 2 which affords a positive engagement between the valve stem shoulder 38 and the plug, thus enabling the latter to be removed from the well. As some resistance may 'be encountered in this operation, it will be seen that the positive engagement between the stem and cap, which latter is an extension of the mandrel, will relieve created by the friction in lifting the plug out of the tubing, placing the entire strain upon the valve stem shoulder and mandrel cap. During this operation it will be apparent that the telescopic connection between the parts 21, 25 of the stem, being shorter than the upward distance traveled by the stem before the shoulder 28 contacts with the cap, will cause a separation of the stem parts. when the parts are re-inserted, however, a reverse movement of the stern will permit reengagement of the two stem parts by reason of the fact that the shoulder 38 will act as a guide, thus insuring the movement of the lower end of the part 21 over the upper end of the part 28 to restore these elements to their normal condition. The downward pressure of water on the valve 29 does not move that valve a sufllcient distance to cause separation between the two parts of the stem.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is:

1. In a device of the class described, the comprevent various tools the key 25 of the load bination of a hollow mandrel having a tapered portion, a plurality of slips surrounding said man'- drel, a wedge member slidable on the mandrel and engaging a wedging surface interiorly of the slips, pistons at the opposite ends of the mandrel, a packer sleeve on said mandrel having a bore to engage the tapered portion thereof, whereby upward pressure on the mandrel will cause the slips to engage a well casing and will also effect a spreading of the packer sleeve against the tubing,

and a downwardly facing valve seat in said mandrel, a valve on said seat, a spring for holding said valve normally seated, said valve arranged to open under hydrostatic pressure to permit a circulation of fluid through the device.

2. In a device of the class described, the combination of a hollow mandrel, means carried by said mandrel and movable longitudinally thereon for effecting engagement between the mandrel and the well tubing, said means being operated by pressure of the oil from the well, and a spring seated valve within said hollow mandrel provided with an upwardly extending stem formed of two slidingly connected parts permitting free movement of the lower part with the valve under hydraulic pressure from within the mandrel to permit circulation of fluid therethrough.

3. In a flow preventer, a hollow mandrel provided interiorly with a valve seat, a valve stem and valve within said mandrel, the valve being normally seated by a spring, means operable by pressure from the well to efiect a locking of the mandrel to the well tubing, means operated by the same pressure for eflecting a tight joint between the flow preventer and well, said spring being of suillcient strength to hold the valve closed during the application of that amount of pressure necessary to force the flow preventer down into the well but arranged to yield and permit the valve to open under excess fluid pressure from above to cause circulation of said fluid through the flow preventer.

4. In a flow preventer, a hollow mandrel, pistons on the mandrel arranged near opposite end portions thereof, a tapering member on said mandrel, a packing sleeve on said mandrel, slips carried by the mandrel, a wedging element for spreading said slips operable when the mandrel is moved upward by pressure within the well, a valve seat in said mandrel, a valve stem and valve in said mandrel, and a spring for seating said valve, said spring being of strength sufficient to prevent the valve from being unseated by pressure from above until a predetermined pressure has been exceeded, thus permitting circulation of the fluid downwardly and through the flow preventer.

5. In a flow preventer, a hollow mandrel, packing means and slips surrounding said mandrel, means sliding upon said mandrel for effecting outward movement of the packing and slips due to pressure from the well, a two-part valve stem the members of which are in telescopic engagement located in said mandrel, a valve carried by the lower section of said stem, a spring for normally holding said valve to its seat, and a shoulder on the upper portion of said stem arranged for engagement with an abutment carried by a portion of the mandrel to permit relative engagement between said portion of the valve stem and mandrel in withdrawing the flow preventer from the well.

6. In a flow preventer, a hollow mandrel proprovided with a valve seat, a two-part valve stem in said mandrel having telescopic connection with each other to permit relative movement of said parts to each other, a spring pressed valve carried by one of said valve stem parts and arranged to be held on said valve seat by its spring, the other portion of said valve stem provided with a transversely extending key, and with a shoulder above said key, said key arranged for movement through slots in said mandrel, and said shoulder being arranged for engagement with an abutment carried by the mandrel for withdrawing the flow preventer from a well.

7. In a flow preventer, a hollow mandrel provided with a valve seat and an externally tapered portion, a plurality of slips surrounding said mandrel, a tapering sleeve slidable on the mandrel and engaging a wedging surface interiorly of said slips, pistons on the opposite ends of said mandrel, a packer sleeve on said mandrel having a bore to engage the tapered portion thereof, whereby upward pressure on the mandrel will cause the slips to engage a well casing and movement of the mandrel thereafter under pressure against the lower piston will effect a spreading of the packer sleeve in engagement with the well casing, a valve stem in said mandrel provided with a shoulder and having a transversely extending member which slides in slotted portions in said mandrel wedge member and slips and arranged upon upward movement of the stem to lift the slips and packer upwardly and thereafter through engagement of the shoulder on the stem with an abutment in said'mandrel to efl'ect withdrawal of the flow preventer from the well.

8. In a flow preventer, the combination of a hollow mandrel provided with an enlarged conical portion, expansible slips surrounding said mandrel, a packer surrounding the conical portion of said mandrel, means for spreading said slips upon upward movement of the mandrel, pistons located on opposite ends of the mandrel, a valve stem having a valvethereon within said mandrel, a spring normally holding said valve against a seat therein, and ports arranged for the entrance of fluid near one end of the mandrel and for the exit of said fluid near the opposite end of said mandrel.

9. In a flow preventer, a hollow mandrel provided with means for circulating fluid therethrough, means for arresting upward movement of said mandrel actuated by pressure from the well, pistons located near opposite ends 01' the mandrel, a stem in said mandrel, a combined stop and guide on said stem for engagement with an abutment on the mandrel at the upper terminal of movement of the stem when withdrawing the latter from the well, and a sleeve having soft metal internal threads for threaded engagement with said valve stem to provide a rupturable connection between said stem and sleeve upon the application of an upward force to withdraw the flow preventer from a well.

10. In a flow preventer, a hollow mandrel provided at its ends with means permitting the entrance and exit of circulating fluid therethrough, a packer and slips surrounding said mandrel, means sliding upon said mandrel for effecting outward movement of the packing and slips due to pressure from the well, a two-part valve stem in said mandrel the members of which are in telescopic connection, a valve carried by the lower section of said stem, a string for normally holding said valve against a valve seat in said mandrel, and a projection on the upper portion of said stem arranged for engagement with an abutment within the mandrel to permit withdrawal of the mandrel from the well when an upward pull is exerted upon the upper portion of the valve stem.

WILLIAM K. -EDWARDS. ORLAND THONIPSON.

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