US2231282A - Removable bridging plug for oil wells - Google Patents

Description

Feb. l1, 1941.. M. E. NoRRls nMovAgLn BRIDGING PLUG Fon on. WELLS Filed Jn. 22. 1940 www.

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Mortimer E. Norris, Balrerseld, Calif.

Application January 22, 1940i, Serial No. 314,989

4 Claims; (Cl. 166-13) My invention relates to a bridging vplug for oil and gas wells and has for its principal objects, to generally improve upon and simplify the construction of the bridging plugs now in general use, to provide a plug having a chamberedA flexible member that is capable of being expanded as aresult of pressure pumped into the chamber or chambers within said flexible member and which member, when expanded, adjusts itself to the irregular surface of the well hole and provides a iiuid pressure uight joint between the plug and the hole and further, to provide a bridging plug of the character referred to that may be easily-and conveniently run into the hole, expanded and afterwards withdrawn from the hole, and the use of which plug greatly facilitates the functionsincident to the testing of the formations throughout the length vof the well hole and at the same time eliminating the troublesome and expensive cementing jobs that usually attend testing operations or the plugging of the well hole at different elevations.

A further object of my invention is, to provide a relatively simple and highly eilicient bridging plug that is expanded by uid pressure so as to completely bridge or seal the well hole at any desired point and said plug having associated therewith valvular means for controlling the uid pressure utilized in expanding the plug andkalso for controlling any relatively high pressures that may develop in that? portionV of the well hole below the plug.-

With the foregoing and other objects in view, my invention consists in certain novel features of construction and arrangement of parts that will be hereinafter more fully described and claimed and A.illustrated in the accompanying drawing in which:

Fig. lis a vertical section taken lengthwise through the center'o my improved plug and showing. the same positioned in a well hole.

Fig. 2 is an enlarged horizontal section taken on the line 2-2 of Fig. 1.

Fig. 3 is a detail section of a punch pin that is i utilized for unseating the check valve that is positioned at the upper end of the plug.

Fig. 4 is a horizontal section taken on the line of Fig. 3.

Fig. 5 is a vertical section taken through the center of a box or coupling that may be used immediately above the plug and which box con-y, tains a check valve utilized for controlling the circulating iiuid that is pumped into the well hole.

Fig. 6 is a vertical section taken lengthwise through the center of a modiiied form of the plug and which is used in making tests in the well hole.

Referring by numerals to the accompanying drawing and particularly to the form of expanding plug illustrated in Figs. 1 to 5 inclusive, I designates a metal tube that functions as a carrier for the various parts of the plug and the upper end of this tube is externally threaded so as to be screw-seated in the internally threaded lower portion of a combined coupling and valve housing Il. t

. Arranged within memberJl isa partition Iz having an aperture that is normally closed by anupwardly seating check valve I3 and the latter being normally held on its seat by an expansive coilspring Il. The lower end of this spring Hi rests on a partition I5 that is formed in the lower portion of member II and which isprovided with a series of apertures I6. ,I

-The internally threaded upper end portion of coupling I2 is adapted to receive the threaded lower end of a. drill 'pipe Il or the like and which serves to lower the plug into the well hole and to lift it therefrom.

The externally threaded lower end of tube ID is screw-seated in `a combined valve housing and coupling member I8 within which is formed a partition i9 having an opening and normally resting on top of said partition I9 and closing the opening therein is a downwardly seating check valve 2t that is yieldingly retained on its seat by an expansive coil spring 2|. The upper end of the coil spring bears against a partition 23 that is formed within the housing I8 and said partition being provided with apertures 24. The internally threaded lower portion of the coupling member I8 receives the threaded upper end-of a circulation tube 25.

Positioned upon the tube IIJ between the coupling members II and I8 is a substantially cylindrical body 26 of rubber or composition of which rubber is the principal ingredient and formed in the central portion of this body adjacent the tube II) is an angular chamber 21 that has communication with the passage through tube I0 by means of apertures 28 that are formed in the wall of the tube. Expansible body 26 is securelyY anchored to tube Ill by means of flanges 29 that are formed on said tube II), which anges are preferably dovetail in cross section and which project into the body 26 above and below the chamber 2h The end portions 35, of the `expamsible lbody 25 are tapered and enclosing same are metal caps 3| that taper slightly toward their outer ends.

Nuts 32 are screw-seated on the threaded portions of tube I0 and when said nuts are tightened against the ends of the caps 3|, the latter are clamped against the-tapered ends of body 26,

thereby cooperating with the dovetailed anges 29 in anchoring said bodylto tube Ill. The expansible body 26 may be of any desired length.

In Fig. 5 I have illustrated a downwardly seating check valve that may be utilized in the line I1 above the valve I3 for the purpose of controlling the circulation in its ow through the well hole and the drill pipe and also for controlling pressures that may develop in the well hole adjacent the plug.

' This valve includes a housing 33 that is located in the line I1 above housing II and seated in the wall of said housing midway between its ends is the lower outer end of an elbow fitting 34, the upper inner end thereof being provided with a valve seat 35. Adapted to rest on said valve seat is aball check valve 36 from the top of which projects a short stem 31 carrying on its upper end a head or knob 38 that is adapted to be engaged by a conventional expanding socket 39 and which latter may be run into the line I1 by means of a sand line or the like. I

For the purpose of unseating check valve I3 to relieve the pressure in the chamber 21 of the expanding member 26 in order that the plug may be pulled from the well, a ring 40 is seated in the lower end of the line I1 and said ring being provided with a spider 4I from which depends a short pin or finger 42.

Thus when the line I1 carrying the ring 40 and pin 42 is lowered intothe Well hole for the purpose of removing the plug and vthe lower end of line I1 is screwed into the` upper end ofthe' valve housingI II, finger 42 will unseat check valve I3, thus permitting pressure from the chamber 21 and within the tube I0 above the downwardly seating check valve 20, to pass upwardly into line I1 past the open valve I3.

- In the use of the form of bridging plug just described, the drill tube .or line that carries the plug is lowered into the well to the desired depth with the expansible body 26 deated andy circulation under pressure is now pumped downwardly through the line I1 and passes fromP tube II! through the apertures 28 into chamber 21 so thaty that portion of member 26 between the caps 3| will be expanded so as to make close contact with the adjacent surface of the well hole or with the inner face of .the casing in the event V-that casing has been runlinto the hole and thus, the ow or passage of oil, liquids, and gas through the well hole past the expanded member 26 is effectually prevented. The pressure pumped 'downwardly through line I1 will open the upwardly seating check valve I3, but cannot pass downwardly seating check valve^20.

In the event that pressure develops in the hole below the plug and such pressure exceedsthe the latter is lowered into the well and when the lower end of the line is screwed into the valve housing II, pin 42 will unseat check Valve I3, thereby relieving the pressure within the chamber 21 and permitting vthe expanded portio'n of the body 26 to collapse and in such condition to be drawn from the well. v

When the valve structure, Fig. 5, is used, the housing 33 is located in line I1 above the valve housing Il and without the ball check valve 36, the plug and valve housing are lowered into thc well to thedesired position. Circulation pumped downwardly through line I1 will discharge outwardly through elbow tting 34 and now downwardly past the-unexpanded plug` into the lower portion of the well hole.

The use of the valve housing 33 and elbow 34 enables any liquid that may occupy that portion of the well hole into which the plug is positioned,

to flow upwardly through elbow fitting 34 into the pipe I0 and into the line I1.

Before starting the pump to force circulation fluid under pressure downwardly through line I1 to expand member 26, ball 36 is dropped into line I1 and after passing downwardly therethrough will rest on seat 35, thus providing a downwardly seating check valve and the circulation fluid under pressure will then flow from line I1 downwardly through the valve housing 33 into tube I0 and from thence into the chamber 21 to expand member 26.

To lift the check valve 36 from its seat and remove the same from the line, a' conventional expanding socket 39 is applied to the lower end of a sand line or the like and lowered into the line I1 until said socket engages the head 38 on the stem 31 that projects upwardly from ball 36.

In Fig. 6 I have shown a form of plug that is especially'designed for use in testing operations and this form of plug comprises an expansible body 43 of 3yrubber, having a centrally arranged chamber 44 and said body being anchored on a tube 45 with the ends of said body occupying caps 46 that are held in position by nuts 41 screwed onto tube 45.

Located in tube 45 below the expanding body 43 is a downwardly seating check valve 48 that performs the same functions as check valve 2U previously described.

Formed through the wall of tube 45 within chamber 44 are apertures 49 that are normally closed by spring pressed ball check valves that are arranged for operation within a valve housing 5I and which latter is secured to tube '45 around the openings 49 therein.I

Formed in valve housing 5I are apertures 52 that establish communication between the chamber within the valve housing and the chamber 44 in expansible member 43.

In the use of the plug just described, the line 45 carrying the plug is run into the well hole to the desired depth and any iluid or pressure in the well'hole below the plug will flow upwardly past check valve 48 and thence upwardly through the line 46. When it is desired to expand the plug, pressure is pumped downwardly through line 45 and such pressure being unable to pass downwardly seating check valve 48 will unseat valves 50 and flow through openings 49, thence through the openings 52 in valve housing 5I, thereby filling chamber 44 and expanding member 43 until the same is forced into close contact with the adjacent surface of the well hole.

After the tests have been made, a. swa'ge is run downwardly through tube 45 so as to engage and unseat check valves and the pressure within the chamber 44 is now free to ow through the openings 49 into tube V42', thereby relieving the pressure in chamber 44 and permitting member 43 to return to its normal position.

When member 43 is expanded, the passage of liquid within the well hole above the plug downwardly into the well hole past saidplug, is effectually prevented. v f

'Thus it, will be seen that I have provided a removable bridging plug for oil wells that is relatively simple in construction, inexpensive of manufacture and very effective in performing the functions for which it is intended.

Among theparticular advantages of my improved plug are, the ability to conveniently raise and lower the plug 'to any desired point in the well for the purpose of making tests and for the bridging or plugging of the well 'hole at any scope` of which' is set forth in the appended claims.,

I claim as my invention: A

l. A bridging plug for oil wells comprising a tube provided in its wall with 'an opening, an. expansible member anchored on Asaid tube, said expansible member having a chamber that com-l municates with the' opening in the wall of the tube, an upwardly seating check valvein the tube above the expansible member, a downwardly seating check valve in said tube below said expansible member, a valve housing in the tube above said upwardly seating check valve, a tubular tting within said valve housing, said tting having an opening on the side of said valve housing communicating with the exterior of the tube 'and a valve seat within said valve housing .on the inner end of said tting and a valve removablypositioned -on said valve seat.

2. In a bridging plug for oil wells, a tube provided in its wall with an opening, an expansible member positioned on said tube and provided with a chamber that communicates with the' housing located in said tube above said expansible member, a tubular elbow fitting having one end seated in the wall of said valve housing, the other end of said tting being provided' with a. valve seat, a valve adapted to rest on -said valve seat and a stem projecting upwardly from said valve.

MORTIMER E. NORRIS.

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