US2207255A

US2207255A - Casing head

Info

Publication number: US2207255A
Application number: US283800A
Authority: US
Inventors: John A Jesson; Kyle Samuel Clyde
Original assignee: JESSON; R A WATSON
Current assignee: JESSON; R A WATSON
Priority date: 1939-07-11
Filing date: 1939-07-11
Publication date: 1940-07-09
Anticipated expiration: 1957-07-09

Description

July 9, 1940 J. A. JEssoN Er'AL GASING HEAD Filed July l1, 1939- IN VENT ORS.

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Patented July 9, 1940 UNITED STATES PATENT OFFICE CASING HEAD Calif.

Application July 11, 1939, Serial No. 283,800

4 Claims.

Our invention relates to well fittings and has particular reference to a casing head finding particular utility when employed on deep pumping Wells such as oil wells.

In the oil producing industry the very deep wells employed are lined throughout the greater part of their length with a casing which protrudes above the ground surface. If the well is not of the flowing type so that it is necessary to operate pumping equipment in order to remove the liquid from the well, a pump is placed near the bottom of the well and connected by a sucker rod string to a reciprocating mechanism located at the ground surface and adapted to reciprocate the pump plunger to effect the desired pumping operation.

In case such pumping equipment is employed, it is necessary to separate the pumped iiuid from whatever gases may be generated within the well or discharged upwardly through the casing and for this purpose it is common practice to employ a string of ow tubing disposed substantially concentrically within the casing and connected to the pump cylinder located at or near the bottom of the well.

The termination of these three elements; namely, the casing, the ow tubing, andthe sucker rods at the ground surface give rise to the problems of providing separate discharge for the gases and the pumped liquids, means for supporting the weight of the string of iiow tubing and the pump mechanism carried thereon, and a means to permit the passage of the sucker rods through both'the oil conveying spaces and the gas conveying spaces without permitting cross ow between these spaces. Furthermore, the mechanism employed in the top of the casing must be so constructed as to permit the ready removal of the sucker rods, the ow tubing and the pump- 'ing mechanism which is disposed below the ground surface.

Prior to our invention, it has been common practice to employ three separate sets of ground surface equipment for performing these various functions. 'Ihis equipment included a casing head which was secured to the upstanding end of the casing and which provided a discharge outlet for gas which collected between the casing and the flow tubing. To the casing head was clamped a casing top which served the dual purpose of sealing off the flow tubing from the gas discharge space and for supporting the entire set of tubing string and pump carried thereby upon the casing. A tubing head was then afxed to the top of the casing top and included means for-discharging the ilow of pumped fluid into suitable now lines and a means for providing a seal or packing gland between the sucker rods and the flow tubing.

This present method of providing the necessary facilities at the ground surface of a pumping well is characterized by the primary disadvantage of employing a great many separate parts which give rise to a high cost of maintenance and the introduction of many possibilities for accidents and trouble through the many interconnections employed between these various parts. Furthermore, the employment of such a relatively large number of parts caused the initial cost of intialiiling such ground surface equipment to be very It is accordingly an object of our invention to avoid the above noted disadvantages by providing a well fitting combining a single unit the functions oi a casing head, casing top and tubing head.

It is also an object of our invention to provide a well fitting or casing head of the character set forth in the preceding paragraph which employs a single means for carrying the weight of the tubing string and for sealing between the tubing and the interior of the well casing.

It is a further object of our invention to provide a casing head of the character set forth in the preceding paragraph which includes a means for locking the tubing within the casing head to prevent axial movement thereof.

It is also an object of our invention to provide a casing head of the character set forth in the preceding paragraph which includes an externally accessible means for adjusting the seal between the flow tubing and kthe gas conducting space thereabout.

It is an additional object of our invention to provide a casing head of the character set forth in the preceding paragraphs which includes separate iiuid and gas discharge outlets.

It is also an object of our invention to provide a casing head construction of the character set forth in the preceding paragraphs with a means for passing the sucker rods from the interior of the flow tubing to the exterior of the casing head and sealing to prevent either liquid or gas flow.

It is also an object of our invention to provide a casing head of the character set forth in the preceding paragraphs which includes a single set of securing devices so constructed that removal of such single set permits the removal of theI sucker rods and the iiow tubing from the well without removing the casing head therefrom.

Other objects and advantages of our invention will be apparent from a study of the following specincations, read in connection with the accompanying drawing, wherein:

Fig. 1 is an elevational view partly in section illustrating the details of construction of the preferred form of casing head of our invention;

Fig. 2 is a view similar to Fig. 1 showing the manner in which the various parts are removed to permit removal of the tubing string from the well; and

Fig. 3 is a horizontal section taken substantially along the line III- III of Fig. 1 to illustrate the relative location oi the securing means employed and the clamping means for adjusting the seal between the tubing string and the gas discharge space.

Referring to the drawing, we have illustrated in Fig. 1 the preferred embodiment of ,our invention as comprising a casing head body I which is adapted to be tightly secured to the upper end of a casing string 2 by any suitable means such as screw threads 3. 'I'he casing head body I is provided with one or more hubs 4 which are bored and internally threaded as indicated at 5 to provide a connection to a gas discharge tube, the bore 5 communicating with a cavity or space defined by the interior of the casing head body I.

In order that the casing head body I may be employed also for holding and supporting the weight of a string of flow tubing 6, we provide an annular inwardly extending ledge 1 which is provided with a substantially plane upper face 8. A supporting ring'9 having an exterior diameter substantially equal to the interior diameter of the casing head body I is placed within the casing head in a. position resting upon the plane face 8 dened by the ilange or ledge 1. The supporting ring 9 is provided with an internal bore I0 adapted to pass the body portion of a tubing hanger I I which is securedy in the conventional fashion by screw threads I2 to the upper end of the ow tubing 6. 'I'he bore I0 through the ring 9 is counterbored as indicated at I3 to provide a substantially plane radial ledge or seat I4 adapted to be engaged by a similar complementary ange I5 ordinarily formed on the tubing hanger II.

It will be observed that the weight of the string of flow tubing 6 is, in this fashion, carried by the casing head body I since downward movement of the supporting ring 9 is prevented by engagement of the'ring with the flange 1 and in a similar manner downward movement of the flow tubing 6 and the tubing hanger Il secured thereto is prevented by engagement of the flange portion I5 thereof with the bottom I4 of the counterbore I3.

In order to provide ,a gas tight .seal between the flow tubing 6 and the annular gas space between the exterior of the ow tubing 6 and the casing 2 which communicates with the gas discharge 5, we prefer to employ gaskets I6 and I1 between the ring 9 and the flange 1 and between the ange I5 and the bottom I4 of the counterbore I3. In this fashion the annular ledge 1, the supporting ring 9, and the tubing hanger II operate as a partition dividing the casing head body I horizontally in such fashion that uid pumped through the interior of the flow tubing 6 is conned tothe space above this partition.

In order that the uid which is pumped through the flow tubing 6 may be transmitted to storage tanks or pumping units as desired, we provide one or more hubs I8 which are provided with a threaded bore I9 communicating with the interior space within the casing head body I above the end of the tubing string 6. I'he bore I9 may, if

The casing head body4 I is provided with an opening 26 at its upper end of a diameter sumcient to pass the supporting ring 9 so that the flow tubing 5 and the supporting ring 9 may be removed upwardly and clear of the casing head body I without-requiring that the connection between the body I and the casing 2 be disturbed. 'I'he opening 20 is preferably closed by means of a top plate 22 which is secured to the upper end of the casing head body I by a single set of securing means which may comprise bolts 23 passed through the top plate 22 and threadedly engaged with the upper end of the casing head body I. I'he top plate 22 is preferably drilled and tappedto receive a plurality of adjusting or clamping bolts 24 fwhich extend downwardly through the top plate 22 in a position to engage an upper clamping ring 25. The clamping ring 25 is made circular in shape having an outside diameter substantially equal to the outside diameter of the aforementioned supporting ring 9 and is provided with a central bore 26 adapted to pass over the upper end of the tubing hanger It will be observed that rotation of the clamping screws 24 to move them downwardly through the threaded connections with the top plate 22 will cause the lower ends thereof to bear against the upper clamping ring 25 and force the same downwardly against the upper surface of the tubing hanger flange I5 and operate to clamp the supporting ring 9 between the tubing hanger II and the flange 1. The heads of the adjusting screws 24 being disposed exteriorly of the casing head body I permits the adjustment of the seal which is provided by the gaskets I6 andI I1 without requiring any disassembly of the device.

Inasmuch as the pump which is carried by the lower end of the string of ow tubing 6 is ordinarily operatedA through a string of sucker rods. the upper section thereof or polished rod 21 must pass from within the interior of the flow tubing 6 to mechanism located exteriorly of the casing head body I which is adapted to provide the necessary reciprocating motion to the polished rod 21 to effect the pumping operation. A liquid tight seal may be provided between the polished rod 21 and the fluid space defined within the casing head body I by providing a packing gland of conventional construction which may include a cylindrical body portion 28 threadedly engaged with the top plate 22. Within the bore of the body portion 28 is disposed conventional packing 29 adapted to be clamped into sealing engagement with the exterior surface of the polished rod 21 by means of a clamping element 39 cooperating with an adjusting cap 3|.

Attention is called to the fact that the removal of the single set of securing means 23 permits the removal of the top plate 22 so that the string of sucker rods may be removed and so that the entire tubing string may be removed from the casing without requiring other dismantling operations to be performed on the casing head of our construction. l

'I'he manner in which the parts are disassociated at the time the tubing string is removed is illustrated in Fig. 2. In this ligure the polished rod 21 and the string of sucker rods secured thereto has been removed by removing the top plate 22. Any suitable hoisting device may. be engaged with the upper end of the tubing hanger II and a hoisting force applied to raise the tubing string l6. Raising of the tubing string 6 lifts the tubing hanger Il from the supporting ring 9 on which it is carried, upward movement of the tubing hanger Il also operating to remove from the casing head I the upper clamping ring 25.

From the foregoing it will appear that we have provided a new and simple casing head construction which performs all of the functions previously performed by a casing head, casing top and tubing head and which is composed of a minimum number of parts and interconnections between these parts, thus providing for a low cost manufacture and trouble-free maintenance of the device.

While we have shown and described the preferred embodiment of our invention, we do not desire to be limited to any of the details of construction shown or described herein, except as defined in the appended claims.

We claim:

1. In a casing head for use on the upper end of a well casing enclosing a string of flow tubing terminating in a flanged tubing hanger, the combination of: a casing head body having means for attachment to the upper end of a well casing; a cavity in said body; a support formed on said body and extending into said cavity; a supporting ring resting upon said support and having an opening for passing said tubing; seat means on said ring for receiving the iiange of said tubing hanger to support said string of tubing within said casing, said support, ring and iiange defining a partition dividing said cavity into a gas space communicating solely with said casing and a liquid space communicating solely with said tubing; an opening in the top of said body of a size suncient to pass said ring; and removable closure means for closing said opening, whereby removal of said closure means permits removal of said ring and said ow tubing.

2. In a casing head for use on the upper end of a Well casing enclosing a string of flow tubing terminating in a iianged tubing hanger, the combination of: a casing head body having means for attachment to the upper end of a well casing; a cavity in said body; an annular ledge formed on said body and extending into said cavity; a supporting ring resting upon said ledge and having an opening for passing said tubing; seat means on said ring for receiving the ange of said tubing hanger to support said string of tubing within said casing, said ledge, ring and iiange deiining a partition dividing said cavity into a gas space communicating solely with said casing and a liquid space communicating solely with said tubing; sealing means interposed between said flange and said seat and between said ring and said ledge to prevent passage of iiuid between said gas space and said liquid space; and clamping means carried by said body in a position disposing a part exteriorly of said cavity and another part in engagement with said flange for clamping said sealing means.

3. In a casing head for use on the upper end of a well casing enclosing a string of flow tubing terminating in a flanged tubing hanger, the combination of: a casing head body having means for attachment to the upper end of a well casing; a cavity in said body; an annular ledge formed on said body and extending into said cavity; a supporting ring resting upon said ledge and having an opening for passing said tubing; seat means on said ring for receiving the flange of said tubing hanger to support said string of tubing within said casing, said ledge, ring and flange defining a partition dividing said cavity into a gas space communicating solely with said casing and a liquid space communicating solely with said tubing; sealing means interposed between said flange and said seat and between said ring and said ledge to prevent passage of fluid between said gas space and said liquid space; a clamp plate resting upon said flange and having a bore aligned with said tubing; and clamp means carried by said body in a position disposing a part exteriorly of said cavity and another part in engagement with said clamp plate for clamping said sealing means.

4. In a casing head for use on the upper end of a well casingenclosing a string of flow tubing terminating in a flanged tubing hanger and having a polished rod extending upwardly therethrough, the combination of a casing head body having means for attachment to the upper end of said'well casing; acavity in said body; an annular ledge formed on said body and extending into'said cavity; a supporting ring resting upon said ledge and having an opening for passing said tubing; seat means on said ring for receiving the flange of said tubing hanger to support said string of tubing within said casing, said ledge, ring and iiange defining a partition dividing said cavity into a gas space communicating solely with said casing and a liquid space communicating solely with said tubing; an opening in the top of said body of a size suiiicient to' pass said ring; removable closure means for closing said opening; an opening in said closure means for passing said polished rod; and packing means interposed between said polished rod and said closure means to prevent escape of liquid through said opening.

J OI-IN A; JESSON. SAMUEL CLYDE KYLE.