US1629749A - Casing head - Google Patents

Description

I May 24, 1927- 1,629,749 M. L. SWEENEY CASING HEAD Filed Aug. 19, 1924 2 Sheets-Sheet 1 W702: Moran/Y L. SWEENE);

ATTORNEY.

y M. L. SWEENEY CASING HEAD Filed Aug. 19, 1924 2 Shoots-Sheet 2 jvlyvwog: Mafia/w L. 5WEE/VE);

ATTOENEY w M Y M M w B .7 Z. 3 F 0 0 Y 45 9 5/ 5 0 040 5 6 5 5 I 111 j l 2 F R. 5 v. 6 %M W 5 Patented Ii/lay 24, 1927. I p UNITED STATES 1,629,749 PATENT OFFICE.

MORGAN L. SWEENEY, or s ANeELr'is, CALIFORNIA; ASSIGNOR 'ro umoiv TANK &

- PIPE 00., A CORPORATION or CALIFORNIA.

CASING HEAD.

Application filed August 19, 1924.' Serial No. 732,888.

My invention relates to the art of drillmg 011 wells. In that art it is common practice to place steel pipe inside the well. for

the purpose of holding up the walls thereof threaded on both ends and joined by suitable collars to form a continuous string.

Casing of this type is commonly termed screw casing, and several concentric strings are sometimes necessary in a single well. Such casing is commonly cemented to the surrounding formation at its lower end, and the process of cementing it has been very highly developed.

Of late years a very serviceable type of easing has been developed, this casing consisting of short lengths of steel plate which are bent up to form a cylinder, two thicknesses of plate being used to form the easing, the two concentric plates of cylinders being riveted, welded or otherwise secured together. Casing of this type was formerly used only for shutting off the loose sand and gravel for the first few, hundred feet of wells, and no attempt was made to use such casing for obtaining water shut-ofi's. I have been able, however, to construct casing of this type which is watertight and which is superior to screw casing, in that 'it is stronger and more flexible, is of uniform diameter, and needs no collars. Such casing is ordinarily made up in lengths of approximately 20 feet, and. these lengths are secured together at the well to form a uniform and continuous string of pipe. This pipe is commonly provided with annular rings or ridges extending therearound at regular intervals, these rings serving to strengthen the pipe against collapsing pressures, and also serving as a point of attachment for elevators thus facilitating the handling and placin of the pipe. Such pipe is of considerab e mechanical strength and is able to withstand suflicient pressure.

It has provided practicable to usestrings of my improved pipe 1500 feet or more in length, these strings being cemented in place at the bottom. is necessary to first establish a water circulation downwardly through the casing itself and upwardly thcrcaround'between the eas- In cementing any well, it

ing and the walls of the well. After this circulation is established, cement is pumped downwardly through the casing and follows the water into the spaces around the outside of the lower end of the casing, where it is allowed to stand and set. Such cementing operations may require a pump pressure of several hundred pounds per square inch' to establish the initial circulation and properly force the cement into thespace outside the casing. It is common practice to screw a circulating head to the top of the screw casing for the purpose of providing a point of attachment for the pumps. Since my stove pipe casing is not threaded, it is impossible to use the' ordinary circulating head with such casing.

1t is highly desirable that the circulation be established immediately after the casing be quickly attached to theupper end of the stove pipe casing.

It is a further object of my invention to provide a casing head which will'make a fluidtight joint with the end of a smooth casing, which will be able to withstand suf-- ficient pressure to allow the cementing operations to be later carried on.

Further objects and advantages will be made evident hereinafter.

Referring to the drawing which is for illustrative purposes only,

Fig. 1 is an elevation partly in section showing the method of establishing a circulation and cementing a string of" stove pipe casing.

Fig. 2 is an elevation of one form of casing head embodying my invention.

Fig. 3 is a section on a'plane represented by the line 3-3 of Fig. 2.

Fig, 4 is a lan view on a plane represented by the line 44 of Fig. 2.

Fig. 5 is a section through the completed cemented joint.

In cementing an oil well using my invention, a string of casing 11 is commonly lowered into the hole 12 by a suitable hoisting and suspension means, not shown. At the time the casing is placed in the well, the hole 12 is commonly full of heavy mud, such as is commonly used in rotary drilling. The casing is lowered down to a point just above where it is desired to cement and th! first step is to establish a circulation, whicl 3 is commonly accomplished by means of a pump 13, this pump taking water or mud from a sump 14 through a pipe 15, and forcing this water and mud through a pipe 16 into the top of the casing. The fluid forced downwardly through the casing flows upwardly through a space 17 outside the casing and overflowslthrough a ditch 18 into the sump 14.

The circulating operation is continued until it is seen that there is a free fluid circulation downwardly through the casing and upwardly through the space 17. A valve 19 in the pipe is then closed and a valve 20 in a pipe 21 is opened. The pipe 21 extends over to a tank 22 containing Portland cement, and the suction of the pump pulls this cement from the tank 22 and forces it downwardly'through the casing 11 and upwardly into the space 17.

When a sufficient quantity of cement has been pumped into the interior of the casing, the casing head must be removed and a cementing plug put in place to separate the cement from the Water. The circulating head is then replaced, the valve 20 is closed and the valve 19 is opened. The pump then forces the plug downwardly by pumping mud and water into the upper part of the casing above the plug.

The plug is so constructed that it sticks in the bottom of the casing, the immediate increase in pressure indicating to the operator that substantially all the cement has left the casing and is properly placed therearound.

It is highly desirable that the circulation be established immediately after the casing isrdropped into the hole and that the entire operation of establishing circulation and cementing be carried forward as expeditiously as possible. It is, therefore, highly desirable that the connection between the pipe 16 and the top of the casing 11 be one that can be quickly made. It is also desirable that this connection can be quickly broken to insert the plug just prior to turning off the cement, and I have devised the novel form of casing head shown in the drawings to accomplish these purposes.

The novel form of easing devised by me is provided with annular ridges 25 which extend therearound at intervals, the casing being formed of sheet metal bent up to form a cylinder, two layers of sheet metal being used and secured together by welding or riveting, and the joints being broken between the two layers to render the completed casing watertight. The upper end of one layer of the casing is shown at 3 in Fig. 2.

For the purpose of making a tight joint about the casing, I provide four straps 31, each of which goes a quarter way around the casing, the straps being clamped to the weaves casing by means of bolts 32. Pivoted on these bolts are draw-down bolts 33, which are provided with nuts 34 on-their outer ends. The draw-down olts 33 fit in notches 35 in a plate 36. This plate has an annular groove 37 in which packing 38 is placed, the plate 36 being drawn down by means of the nuts 34 so as to force the packing 38 against the end of the casing 30. The clamps 31 may be conveniently placed just below one of the annular ridges 39 of the casing, although this is not absolutely necessary, provided the clamps 31 and the bolts 32 are made of suflicient size to solidly secure the clamp to the casing by friction. Resting againstthe inner side of the plate 36 is a flexible member 40, which is preferably formed of rubber or a rubber compound, and which is sufficiently elastic to allow it to be forced out against the inner surface of the casing 30. For the purpose of so forcing it, I provide four slips 41,

these slips having a conical outer surface 42 fitting against the gasket 40, and being provided with flanges 43. 'The flanges 43 are provided with slotted holes 44, in which cap screws 45 are located, these cap screws being threaded in the plate 36.

For the purpose of expanding the slips 41, I provide an expander 50, this expander having a conical surface 51, fitting a ainst the inside of the slips. The expan er is pulled into the slips by'means of bolts 53 and nuts 54, the bolts 53 extending through the plate 36 and the nuts 54 being located in an accessible position outside the plate. A fluid inlet pipe 60 passes through a stuffing box 61 in the plate 36 and is threaded at 62 in the expander 50. The pipe 60 is secured by means of an "elbow 66 to the pipe 16 and fluid is forced downwardly therethrough by means of the pump 13.

The method of operation of the invention is as follows:

Whenever the casing 11 has been placed in the well, preferably a little above the point where it is desired to cement, the clamps 31 are put in place about the casing and the plate 36 is placed upon the top of the casing 30, the bolts 33 then being swung into place. The nuts 34 are then tightened down to make a moderately tight joint between the packing 38 and the end of the casing 30. The nuts 54 are preferably loosened prior to putting the plate 36 in place, so that the gasket 40 is relaxed and slides readily inside the casing. By tightening up of the nuts 54, the expander 50 is pulled upwardly and the packing is pulled outwardly against the inner wall of the casing. The circulating and cementing operation is then proceeded with as previously described.

When it is desired to insert the plug, it is simply necessary to slacken up on the nuts 34 and 54, the-head being quickly redelayin the operationis occasioned. It will be seen that by 'using my type of circulating head, it is unnecessary to perform any operation whatever upon the smooth unthreaded stove pipe casing, a fluidtight connect-ion being quickly made thereto.

WVhere-it is desired to use long strings of my casing to shut off water, I find it desirable to dip the variouslengths of casing in hot 'asphaltum or some other substance which will adhere thereto, previous to placing it in the well, as the hot material tends" to flow into the spaces between the sheets, thus preventing leaks. The initial fabricated lengths are then welded together as they are placed in the welL.

By the use of my improved casing, I am able to produce a cemented joint which is much superior to the joint made with ordinary screw casing, as will be seen from an inspection of Fig. 5.

In my casing I provide annular ridges 80 which not only serve to lock the two layers 81 and '82 of my casing securely together, but which also serve to lock-the casing solidly in the cement 83. The wall 84 of the hole 12 being irregular in contour, the cement plug 83 is solidly locked to the wall of the well.

The locking of the casing in the cement is Where ordinary screw casing is used, the

smooth outer surface of uniform diameter is only frietionally locked in the cement, and

the casing often moves up or down, thus destroying the bond between the cement and the casing and producing a slow leak. The ridges 80 of my improved casing very effectually prevent this.

I claim as my invention:

1. A casing head comprising: a flexible packing member adapted to be placed inside the open end of a casing; slips fitting inside said flexible packing member; an expander fitting inside said sllps and so formed as to expand said slips a ainst the inner surface of said flexible pac ring. member and thus force said flexible packing member outward against the inner surface of said casing; means adapted to pull said expander in a direction to expand said slips; and an inlet pipe rigidly secured to said expander and extending to the exterior of said casin 2. A casin head comprising: a ,exible pac-king mem er adapted to be placed inside the openend of a casing; slips fitting inside said flexible packing member; a plate a'dapt- I ed to bear directlly ,a ainst the end of said casing; an expan er tting inside said slips so formed as to expand said slips against the inner surface of said flexible packing member and thus force said flexible packing member outward against said inner surface of said casing; means connecting said expander and said plate and adapted to pull said expander in a direction to expand said slips; and an inlet pipe secured to said expander.

3. A casing head comprising: a flexible packing member adapted to be placed inside the open end of a string of oil well casing;

slips fitting inside said flexible packing member; a plate' adapted to bear directly against the end of said casing; an expander fitting inside said slips and so formed as to expand said slips against the inner surface of said flexible member and thus force said flexible packing member outwardly against the inner surface of said casing; bolts connecting said expander with said late and so disposed as to pull said expan er in a 'direction to expand said slips; and means for conducting fluid under pressure to the interior of said casing with said member and said means in place on the casing.

4:- A casing head comprising: a flexible packing member adapted to be placed inside the open end of a string of oil well casing; slips fitting inside said flexible packing member;a plate adapted to bear directly against the end of said casing; packing between said plate and the end of saidcasing; an expander fitting inside-said slips and so formed as to expand said slips against the inner surface of said flexible member and thus force said flexible packing member outwardly against the inner surface of said casing; bolts connecting said expander with said plate and so disposed as to pull said ex- 1 0 pander in a direction to expand said slips;

and means for conducting fluid under pressure to the interior of said casing with said member and said means in place on the casing. '5. A casing head comprising: a flexible packing member adapted to be placed vinside the open end of a strin of oil well casing; slips fitting inside said flexible packing member; a plate adapted to bear directly 1 against the end of sald casing; means for forcing said plate toward said casing; an expander fitting inside said slips and so formed as to expand said slips against the inner surface of said flexible packing mem- 115 as to pull said expander in a direction to ex- 1 pand said slips; and means for conducting fluid under pressure to the interior of said casing with said. member and said means in place on the casing.

6. A casing head packing member adapted to be placed inside the open end of a string of oil well casing;

slips fitting inside said flexible packing member; a plate adapted tobear directly againstythe end of said casing; packing be-- 1" comprising: a flexible 1Z tween said plate andthe end of said casing; means for forcing said plate towardssaid casing; an expander fitting inside said slips and so formed as to expand said slips against the inner surface of said flexible member and thus force said flexible packing member outwardly against the inner surface of said casing; bolts connecting said expander with said plate andso disposed as to pull said expander in a direction to expand said slips; and means for conducting fluid under pressure to the interior of said casing with said member and said means in place on the casing.

7. A casing head comprising: a flexible packing member adapted to be placed inside the open end of a string of oil well casing; slips fitting inside said flexible packing member; a clamp secured about said casing; means secured to said clamp for forcing said plate towards said casing; an expander fitting inside said slips and so formed as to expand said slips against the inner surface of said flexible packing member and thus force said flexible packing member outwardly against the inner surface of said casing;

bolts connecting said expander with said plate and so disposed as to pull said expander in a direction to expand said slips; and means for conducting fluid under pressure to the interior of saidr'casing with said member and said means in place on the eas- A casing head comprising: a flexible packing member adapted to be placed inside the open end of a string of oil well casing; slips fitting inside said flexible packing member; a plate adapted to bear directly against the end of said casing; packing between said plate and the end of said casing;

a clamp secured about said casing; means secured to said clamp for forcing said plate towards said casing; an expander fitting inside said slips and so formed as to expand said slips against the inner surface of said flexible member and thus force said flexible packing member outwardly against the inner surface of said casing; bolts connecting said expander with said plate and so disposed as to pull said expander in a direction to expand said slips; and means for conducting fluid under pressure to the interior of said casing with said member and said means in place on the casing.

9. A casing head comprising: a flexible packing member adapted to be placed inside the open end of a string of oil well casing; slips fitting inside sald flexible packing member; a plate adapted to bear directly against the end of said casing; an expander fitting inside said slips and so formed as to expand said slips against the inner surface of said flexible member and thus force said flexible packing member outwardly against the inner surface of said casing; bolts connecting said expander with said plate and so disposed as to pull said expander in a direction to expand said slips; and an inlet pipe secured in said expander.

In testimony whereof, I have hereunto set my hand at Los Ange es, California, this 12th day of August, 1924.

MORGAN L. SWEENEY.

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