US3095929A

US3095929A - Casing heads for oil wells

Info

Publication number: US3095929A
Application number: US2524A
Authority: US
Inventors: Jack C Mcguire; A J Speegle
Original assignee: Halliburton Co
Current assignee: Halliburton Co
Priority date: 1960-01-14
Filing date: 1960-01-14
Publication date: 1963-07-02
Anticipated expiration: 1980-07-02

Description

D8011 XP. sm m aq {199523 EFERENCE EEAH "ff y 2, 1963 J. c. MCGUIRE ETAL 3,095,929

CASING HEADS FOR OIL WELLS Filed Jan. 14, 1960 2 Sheets-Sheet 1 W TEST PLUG INVENTORS. A J SPEEGLE JACK Q Ma GU/RE July 2, 1963 J. C. M GUIRE ETAL Filed Jan. 14, 1960 2 Sheets-Sheet 2 INVENTORS. A J SPEEGLE Y JACK G. M0 GU/RE United States Patent 3,095,929 CASING HEADS FOR OIL WELLS Jack C. McGuire and A. J. Speegle, Duncan, Okla., assignors to Halliburton Company, a corporation of Delaware Filed Jan. 14, 1960, Ser. No. 2,524 2 Claims. (Cl. 166-97) This invention relates to casing heads for oil wells and the like, and more particularly to a casing head designed for use in fracturing earth formations in wells.

Earth formations in wells are now commonly fractured by pumping liquid into the well as extremely high rates and under extremely high pressure in accordance with the patent to Farris, Reissue 23,733.

Oil or other hydrocarbon liquids are frequently used for the fracturing of petroleum bearing formations, and this operation is hazardous, especially if any leaks develop in the casing head or in the flow lines from the pumps to the casing head.

It is an object of the present invention to devise a casing head for a well which removes some of the hazard while fracturing earth formations thereof. This is accomplished by providing the casing head with a number of valves, together with other special equipment so that all connections and flow lines can be effectively tested under high pressure before the actual process of fracturing is performed.

Other objects and advantages will be apparent from the following detailed description of a preferred embodiment of the invention, taken in connection with the accompanying drawings, in which:

FIGURE 1 is a diagrammatic representation of a casing head constructed according to the invention and showing an assembly of valves and pumps connected thereto; and

FIGURE 2 is a vertical cross-sectional view of a casing head constructed in accordance with the principles of the present invention.

Referring to the drawing in detail, and first to the diagrammatic showing of the assembly in FIGURE 1, it will be seen that an oil well casing is there shown at 10. The casing may be provided with a master valve 11.

At the top of casing 10, there is a special casing head 12, consisting of a tubular body, made of cast steel or the like, and having provision for a tapered seat 13. The casing has a cap 14 and provision for making connection to two

inlet lines

15 and 16 from two pumps 17 and 18.

In actual use, as many as four inlet lines and four pumps are connected to the casing head, but for purpose of illustration, only two are shown and described here.

Each of the inlet lines 15 and 16 is provided with a manually operated control valve and with a check valve. The control valves are designated 20 and 21. The check valves are designated 22 and 23.

The cap 14 has provision for a bleed line 24 and a bleed valve 25. It may have a T 26 and a pressure gage 27.

Fitted within the casing head 12 is a test plug 28. It has a surface adapted to engage the tapered seat 13, and it has a depending piston 29 extending into the portion of the casing head below the seat 13. The piston portion 29 may be provided with O-rings 30 or other packing to maintain a complete and absolute seal between the piston 29 and casing head 12 below the seat 13.

There is a central bore 31 through the test plug 28. At its upper end, the bore 31 is enlarged and tapered to form a seat for a small cone-shaped valve member 32.

The valve member 32 is provided with a stem 33 which has a grappling ring 34 afiixed thereto.

There may be a suitable cage or guide for the stem 33,

Patented July 2,, 1963 as shown at 35 and a very light coil spring 36 urging the valve 32 closed.

In actual practice, the casing head 12 may be made of two parts connected together by a screw thread such as shown at 37 in FIGURE 2.

Moreover, as shown in FIGURE 2, the housings for the

check valves

22 and 23 are constructed integral, in part, with the casing head 12, so that all parts may be quickly assembled and be readily taken apart for inspection or replacement of parts. Thus, the

check valve parts

38 and 39, which contain the seats for the

check valve plugs

40 and 41, are connected to

tubular projections

42 and 43 of the casing head 12 by means of quickly manipulated

threads

44 and 45.

Also, it should be noted that the cap 14 is connected to the casing head 12 by quickly manipulated threads 46.

It will be seen in FIGURE 2 that the casing head 12 is the same diameter at the threads 37 and the threads 46. Thus two or more casing heads 12 may be stacked on the same casing 10, so that any number of pumps may be connected to the casing 10.

To illustrate the manner of use of the casing head of the invention, a simple operation will be described.

Assume that pumps are connected to the casing head, and that all the parts are in the position shown in FIG- URE 1. The pumps 17 and 18 may then be operated, either singly or both at the same time to exert high pressure in the casing head. No fluid can flow down into the casing 10 at this time since the test plug 28 cannot move downwardly in the casing and since seals are maintained by the O-rings 30 and by the small cone-shaped valve 32. Any leaks in the

lines

15 or 16 or any leaks in the valves or at the threads 37 will thus become apparent.

Upon completion of a satisfactory test, the pressure in the casing head 12 is released by opening the bleed valve 25. The cap 14 is then removed and the test plug 28 lifted out by lifting on the grapple ring 34. In this connection it is to be appreciated that the valve 32, in moving upward, will raise the plug carried guide 35 and thus the plug itself. This concurrent movement results from the interaction of abutment means carried by valve 32, which as illustrated, is the upper surface of the valve, and abutment means carried by the plug, which in the disclosed embodiment is defined by the lower surface of the top portion of guide 35. It is obvious, of course, that this interaction may involve direct abutment engagement or abutment engagement with an interposed member such as the disclosed valve biasing spring structure. Where such a spring is employed, the previously noted light spring structure permits valve raising without plug movement.

It will be seen that when the ring 34 is lifted, the valve 32 is opened before the test plug 28 actually is moved upwardly. This equalized the pressure above and below the test plug.

It sometimes happens that a well builds up pressure in the casing when it is closed in, as by gas entering the well from some gas producing formation in the well.

If this happens during the pressure testing of the casing head, it will not cause the test plug 28 to blow out of the well, or up into the casing head 12, when the bleed valve 25 is opened. All that will happen is that the valve 32 will open, against the force of the weak spring 36, and relieve the pressure in the casing 10 below.

On the other hand, the well may go on vacuum during the pressure testing of the casing head 12. If this happens, only enough lifting force need be exerted on the ring 34 to overcome the difference in pressure across the valve 32 to equalize the pressure. The entire test plug 28 can then be lifted.

After the test plug 28 is removed from the casing head 12, the cap 14 is replaced, the bleed valve 25 closed, and

3 the fracturing operation may then be carried out with a minimum of danger that leaks will develop at or near the casing head.

While only one embodiment of the invention has been shown and described herein, it is obvious that various changes may be made without departing from the spirit of the invention or the scope of the annexed claims.

We claim:

1. A casing head and testing apparatus adapted for use in fracturing oil wells or the like comprising:

a body having an apertured portion;

independently removable closure means having coupling means for detachably and sealingly engaging said apertured portion of said body;

means for connecting a plurality of inlet conduits to said apertured body portion;

means for connecting said body to a well casing;

seat means within said apparatus disposed between said apertured body portion and an upper portion of said well casing;

test plug means engaging said seat means, said test plug means being freely and independently movable upwardly and away from said seat means;

packing means sealingly extending between the periphery of said test plug means and an inner peripheral portion of said body;

said test plug means further having fluid passage means extending therethrough to provide fluid communication between the interior of said well casing beneath said test plug means and said apertured portion of said body;

valve seat means in said passage means;

and check valve means between said valve seat means and said apertured body portion and movable toward said valve seat means in response to fluid pressure within said apertured body portion to prevent flow from said inlet conduits to the interior of said well casing beneath said test plug means and movable away from said valve seat means in response to fluid pressure in said well casing while said test plug means remains seated;

valved means for venting the interior of body prior to the removal of said closure means;

said valved means and said check valve means being cooperable to afford relief for fluid pressure in said well casing while said test plug remains seated;

grappling means on said check valve means extending toward said apertured body portion;

first abutment means carried by said check valve means;

second abutment means disposed outwardly with respect to said valve seat means from said first abutment means, spaced from and opposing said first abutment means, and carried by said test plug means, whereby, with said closure means removed from said apertured body portion, said grappling means may be engaged and moved away from said valve seat means to sequentially unseat said check valve means from said valve seat means and, through means of said first and second abutment means, move said test plug means from said seat means;

a plurality of inlet conduits connected to said apertured body portion;

a check valve in each inlet conduit biased to a closed position to prevent flow outward from said body through said conduits, and

pump means associated with each of said inlet conduits for supplying pressurized flu-id to the interior 9: isl y.

2. A casing head and testing apparatus adapted for use in fracturing oil wells or the like comprising:

a tubular body;

an independently removable cap having threaded coupling means for detachably and sealingly engaging the top of said body;

means for connecting said tubular body to a well casing;

means for connecting a plurality of inlet lines to said a seat within said body disposed between an upper portion of said well casing and said connecting means for said inlet lines and facing said cap;

a test plug supported on said seat, said test plug being freely and independently movable axially of and away from said seat toward said cap and having packing carried on its periphery for eflecting a seal with the inner surface of said body;

said test plug further having a bore extending therethrough axially of said tubular body;

a valve seat in and coaxial with said bore;

a check valve between said valve seat and said cap;

said check valve being movable toward said valve seat in response to fluid pressure within said tubular body between said test plug and said cap to prevent flow from said inlet lines to the interior of said well casing beneath said test plug and movable away from said valve seat in response to fluid pressure in said casing while said test plug remains seated;

grappling means on said check valve extending axailly of said body toward said cap;

first abutment means carried by said check valve;

second abutment means carried by said test plug disposed between said first abutment means and said cap, and spaced from and opposing said first abutment means, whereby with said cap removed from said body, said grappling means may be engaged and moved axially of and away from said valve seat toward said open body top to sequentially unseat said check valve and, through means of said first and said second abutment means, lift said test plug for removal through said open body top;

valved venting means connected to said cap for effecting the venting of the interior of said body prior to the removal of said cap;

said valved venting means and said check valve being cooperable to afford relief for fluid pressure in said Well casing while said test plug remains seated;

a plurality of inlet lines connected to said body;

a check valve in each of said inlet lines biased to a closed position to prevent flow outward from said body through said lines;

and pump means associated with each of said inlet lines ior supplying pressurized fluid to the interior of said ody.

References Cited in the file of this patent UNITED STATES PATENTS 1,942,232 Alviset I an. 2, 1934 1,971,330 Carroll Aug. 28, 1934 2,233,077 Gillespie et al Feb. 25, 1941 2,334,303 Allen et al Nov. 16, 1943 2,478,628 Hansen Aug. 9, 1949 2,877,849 Morrison et al. Mar. 17, 1959 2,951,363 Diodene Sept. 6, 1960 2,955,458 Sonnier et al Oct. 11, 1960 2,963,092 Anderson et al Dec. 6, 1960 2,999,545 ig l w S pt. 12, 61

Claims

1. A CASING HEAD AND TESTING APPARATUS ADAPTED FOR USE IN FRACTURING OIL WELLS OR THE LIKE COMPRISING: A BODY HAVING AN APERTURED PORTION; INDEPENDENTLY REMOVABLE CLOSURE MEANS HAVING COUPLING MEANS FOR DETACHABLY AND SEALINGLY ENGAGING SAID APERTURED PORTION OF SAID BODY; MEANS FOR CONNECTING A PLURALITY OF INLET CONDUITS TO SAID APERTURED BODY PORTION; MEANS FOR CONNECTING SAID BODY TO A WELL CASING; SEAT MEANS WITHIN SAID APPARATUS DISPOSED BETWEEN SAID APERTURED BODY PORTION AND AN UPPER PORTION OF SAID WELL CASING; TEST PLUG MEANS ENGAGIND SAID MEANS, SAID TEST PLUG MEANS BEING FREELY AND INDEPENDENTLY MOVABLE UPWARDLY AND AWAY FROM SAID SEAT MEANS; PACKING MEANS SEALINGLY EXTENDING BETWEEN THE PERIPHERY OF SAID TEST PLUG MEANS AND AN INNER PERIPHERAL PORTION OF SAID BODY; SAID TEST PLUG MEANS FURTHER HAVING FLUID PASSAGE MEANS EXTENDING THERETHROUGH TO PROVIDE FLUID COMMUNICATION BETWEEN THE INTERIOR OF SAID WELL CASING BENEATH SAID TEST PLUG MEANS AND SAID APERTURED PORTION OF SAID BODY; VALVE SEAT MEANS IN SAID PASSAGE MEANS; AND CHECK VALVE MEANS BETWEEN SAID VALVE SEAT MEANS AND SAID APERTURED BODY PORTION AND MOVABLE TOWARD SAID VALVE SEAT MEANS IN RESPONSE TO FLUID PRESSURE WITHIN SAID APERTURED BODY PORTION TO PREVENT FLOW FROM SAID INLET CONDUITS TO THE INTERIOR OF SAID WELL CASING BENEATH SAID TEST PLUG MEANS AND MOVABLE AWAY FROM SAID VALVE SEAT MEANS IN RESPONSE TO FLUID PRESSURE IN SAID WELL CASING WHILE SAID TEST PLUG MEANS REMAINS SEATED; VALVED MEANS FOR VENTING THE INTERIOR OF BODY PRIOR TO THE REMOVAL OF SAID CLOSURE MEANS; SAID VALVED MEANS AND SAID CHECK VALVE MEANS BEING COOPERABLE TO AFFORD RELIEF FOR FLUID PRESSURE IN SAID WELL CASING WHILE SAID TEST PLUG REMAINS SEATED; GRAPPLING MEANS ON SAID CHECK VALVE MEANS EXTENDING TOWARD SAID APERTURED BODY PORTION; FIRST ABUTMENT MEANS CARRIED BY SAID CHECK VALVE MEANS; SECOND ABUTMENT MEANS DISPOSED OUTWARDLY WITH RESPECT TO SAID VALVE SEAT MEANS FROM SAID FIRST ABUTMENT MEANS, SPACED FROM AND OPPOSING SAID FIRST ABUTMENT MEANS, AND CARRIED BY SAID TEST PLUG MEANS, WHEREBY, WITH SAID CLOSURE MEANS REMOVED FROM SAID APERTURED BODY PORITON, SAID GRAPPLING MEANS MAY BE ENGAGED AND MOVED AWAY FROM SAID VALVE SEAT MEANS TO SEQUENTIALLY UNSEAT SAID CHECK VALVE MEANS FROM SAID VALVE SEAT MEANS AND, THROUGH MEANS OF SAID FIRST AND SECOND ABUTMENT MEANS, MOVE SAID TEST PLUG MEANS FROM SAID SEAT MEANS, A PLURALITY OF INLET CONDUITS CONNECTED TO SAID APERTURED BODY PORTION; A CHECK VALVE IN EACH INLET CONDUIT BIASED TO A CLOSED POSITION TO PREVENT FLOW OUTWARD FROM SAID BODY THROUGH SAID CONDUITS, AND PUMP MEANS ASSOCIATED WITH EACH OF SAID INLET CONDUITS FOR SUPPLYING PRESSURIZED FLUID TO THE INTERIOR OF SAID BODY.