US2106996A - Bottom tubing plug for oil wells - Google Patents

Description

Feb. 1, 1938. w. K. EDWARDS BOTTOM TUBING PLUG FOR OIL WELLS Filed May 3, 1957 a a 6% Q 4 6 5 A: w a wwfl W bwg 1 V W I \i companying drawing, in which; 4

Patented Feb. '1, 193a,

UNlTED l STATES rA'rENT OFFICE comma.

This invention relates to means for prevent the oil from flowing through tubing in high pressure oil wells'while the tubing is being run into the well. V

Means have heretofore been provided for preventing the flow of oil through the tubing while the same is being lowered into the well, such means being ordinarily in the form of a disk 4 which is capable of being-punctured, either by a puncturing tool or through impact from a weight which is dropped down the hibing, to allow the oil to flow through the tubing after the latter has been inserted in position. Such devices are more or less objectionable because fracture of the disk 15. either by a weight dropped into the tubing, or a tool forcibly moved against the disk, is possible,

as portions of the disk are frequently not removed by these methods. Thus parts of the disks which remain act as an obstruction to the flow 20 of oil, and for this'reason the frangible disk method of checking the flow of oil in tubing hasnot been a success.

An important feature of the present invention consists in a plug which is held in a position to 25 obstruct the flow of oil through the tubing by frictional means. The plug my be dislodged either by hydraulic pressure applied from above by a pump, or may be knocked out by dropping a weight on it from above. In either case the plug 30 is removed as an obstructing element, as an entirety, and drops through the tubing to the bottom of the well so as to be out of the may. thus permitting a free flow. of the oil when such result is desired. lreferi ly. the frictional means for retaining the plugin position is, as herein shown, in the form of an split ring of resilient metal which normally expands into a groove in the walls of the tubing, and holds the plug against dislodgment by the pressure of the oil from below, and retains the plug in position until it is desired to remove it in either. of the ways above mentioned Under a preferred form of the invention the plugjs in the form of a curved member so that when the plug is dislodged its shape. is such as to prevent the nos- 7 sibility of dislodgment in that portion of the tubing below where-the-plug is placed, as for example, when a perforated screw jointof tubingis provided below the plug to'act as a strainer;' '50 or where the extension of the well'tubing below the plug is in the form of a pipe section.

v The foregoing, and other important features of the invention will be hereinafter 1mpre particularly described in connection with the ac-' tion, and

Fig. 1 is a view, partly sectional, illustrating the preferred form of my bottom tubing plug in position in the oil well tubing; L

Fig. 2 is a similar view illustrating a modiflca- 6 Fig. 3 is a sectional view on the line 3-4, mg. 1'.

Sections of the oil well tubing l', 2, and 3 are connected by'coupling collars l and 5, as'is usual.

Referring to Fig. 1, at, a suitable point, preferably near the termination of a section of tubing 2, a 10 ground valve seat I is provided. The tubing plug is composed of an upper disk portion 8 and a lower extension i0 which, as herein shown, is partly cylindrical and terminates at its lower end in a convexly curved portion l2, this part of, the plug resembling generally the shape of a bullet, or plumb bob. The part II of the plug is provided at its upper terminal with a recess or groove it within which is located an expansion ring l6 having a normal tendency to expand outwardly beyond the plug. This ring, when the plug is in the position shown in Fig. 1 in the tubing, is restrained against outward expansion by a recess il formed in the inner wall of the tubing section 2 a suitable distance below the ground seat I.

The disk-shaped part 8 of the plug seats upon theupp r surface of the lower section In and is clamped in position thereonby a threaded bolt I8 having a head l9, and engaging an internal thread in a central orifice of the plug member ID. By such bolt the'parts of the plug, 8, iii, are clamped together and the upper portion of the recess II in the member Iii is closed by the overlapping portion of the disk, thereby forming a, complete groove for the expansible ring it.

It will be seen from the above construction that the bottom tubing plug, comprising the above described parts, is inserted by forcibly moving it upwardly in the tubing until the upper face of 0 the disk 8 seats against the ground seat I, the expansion ring being forced inwardly during such movement and contracted until the plug has become seated, whereupon the ring expands outwardy beyond the perimeter of the cylindrical 4:; portion of the plug member ID, and frictionally holds the plug as an entirety snugly and reliably within .the tubing. When in this position the diskaisseatedonthegroundjointlandanoil tight joint is thus formed to prevent the possiso bility of any oil passing above the plug, due to' y the oil pressure in the well; The'inner surface of the tubing section 2, below the [seat n 101- the expansion ring; is inwardly beveled as indicated at 2., so that in the operation of! forcing the plug 5 tubing at the termination of the bevel 2| therein.

In order to remove the plug it is merely necessary to force water down through a hydraulic pressure apparatus, such as a pump, from above with sufilcient force to dislodge the plug, whereupon it falls freely down into the well and out of the way, or, in lieu of water pressure, a weight may be dropped down into the tubing and by the blow delivered to the plugs cause its dislodgment from the position as shown in Fig. 1 Under either of these modes of dislodgment of the plug it will be seen that the downward pressure must be suflicient' to crowd the expansion ring inwardly into its groove H, thereby permitting free downward movement of the plug.

In the modification illustrated in Fig. 2 I employ a disk 22 provided with a groove in its periphery, 23, in which is seated a split expansion ring I which may be identical in construction with the ring I illustrated in Fig. 1. In this modification, the upper outer face of the disk 22 seats against the ground seat 24 in the tubing section In, to provide a leak-tight joint against the upward passage of oil. In this respect the modification follows the construction of the disk section t of the plug shown in Fig. 1. The tubing section 2a is shown as connected with an upper section In by a threaded collar la, and the lower portion of the section in is threaded for engagement therewith by a coupling collar, the lower inner portion of which is in threaded engagement with a lower tubing section 30. The

. expansion ring it is received in the groove 23 in the outer peripheral face of the ring 22,.and when the latter is seated against the seat 24 in the tubing the expansion ring is in frictional engagement with the seat 28 in the inner wall of the tubing, below the ground seat 24, as shown in Fig.2. Dislodgment of the disk in this case is. effected by either of the means described with reference to the construction shown in Fig. 1; that is, either of downward hydraulic pressure,

. or due to the force of a blow delivered by impact the plug when the latter is dislodged, due to the curved bullet-shaped extension I! which effectively prevents any liability of the plug lodging in the tubing below the seat of the plug, and becoming fixed" in a c'rosswire position therein.

Iclaim:- 1. Abottomtubingplusforoilwellscomprising a disk having its upper face ground to form a tight joint with the seat in a tubing section, said device provided with a peripheral groove, and a resilient expansion ring seated in the groove and arranged to frictionally engage a groove within the tubing section.

2. A bottom tubing plug for oil wellscomprising in combination, a section having a convexly curved outer terminal face, a groove formed partly in said sectioman expansion ring fitting said groove, a disk combined with said section and arranged to overlap the groove at its lower edge, and having its upper edge ground to form a surface to seat against a ground seat formed interiorly of the well tubing.

3. A bottom tubing plug for oil wells comprising a section having an outer convexly curved terminal portion having its upper portion reduced in diameter to form a recess, an expansible elastic ring in said recess, an upper disk portion constructed to overlap said recess forming a groove for said ring, and means for clamping the two portions of the plug together.

4. A bottom tubing plug for oil wells having in combination, a lower bullet-shaped portion havdropped through the tubing, an upper reduced portion to form a recess, an expansion ring in said recess, a disk overlapping the recess and provided with a valve seat at its upper peripheral edge to engage the seat in the tubing, and clamping means for securing the several parts of the plug together.

6. In a device of the character described, the combination with an oil well tubing section provided interiorly with a valve seat facing downwardly, a recess below said seat for receiving an expansion ring, an inclined portion formed below the said recess, of a plug comprising a disk mem ber constructed to engage the tubing seat, an extension member below the disk provided with a recess, a curved lower end extending a substantial distance below the recess, an expansion ring in said recess, and means for clamping the several parts 01 the plug together.

; K. EDWARDS.

comprising a lower section having a reduced terminal to provide clearance for the plug when

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