US1763642A - Apparatus for cementing wells - Google Patents

Description

June 17, 1930- I H. H. DIEVENDORFFF AL 1,753,642

APPARATUS FOR CEMENTING. WELLS Filed June 6 1928 \-3 v k 3 INVENTORS HORTON 19- O/EVE/VOORFF BY S/D/VE? O- 5/7/9704- i. KW?

ATTORNEY Patented June 17, 1930 HORTON H. DIEVENDORFF, OF SANTA PAULA, AND CALIFORNIA, ASSIGNORS TO PACIFIC OIL WELL SIDNEY o. BARTON, or VENTURE, CEMENTING COMPANY, rnoonro- BATED, OF LOS ANGELES, CALIFORNIA, A CORPORATION OF CALIFORNIA APPARATUS FOR CEMENTING WELLS Application filed June 6, 1928. Serial Ito 283,352.

- This invention relates to an improved apparatus for cementing wells for the permanent exclusion of water from petroleum oil and gas bearing formations. In the drilling of wells, steel casing of vvarying diameters is employed as a means of keeping the hole open and as a conveyor of the oil and gas to the surface. A well-known method of excluding water from the oil and gas bearing formations consists in filling the space between the wall of the drill hole and the casing with a suitable cement such as Portland cement, which may or may not be mixed with a reagent ,to regulate the setting time of the cement; Before the cementing operation the 1 hole is drilled to a point below all water hearing formations and into a formation which is impervious to water, such as shale and the like, in order that a water-tight bond may be established between the shale or other formations impervious to water, and the casing,

which is extended to a predetermined point within a few feet of the bottom of the hole.

The common method now employed for I cementing oil wells to establish a water-tight bond below all water bearing formations between the casing and the'drill hole, is generally lmown as the Perkins and Double method, in which a mud or water circulation is first established down through the casing and up through the space outside the casing so that the mud or water overflows at the top.

This mud or water circulationoperation is employed to clean the space between the easing and-the drill hole. After the space between the casing and the drill hole has been cleaned by the mud or water circulation operation, a barrier consisting of a wooden plug with two circular pieces of leather attached. o thereto, commonly called packing rings, is

inserted into the casing from the top. The calculated amount of cement grout is then pumped into the casing from the top or side which forces the plug or barrier down the casing by thehydrauhc pressure and weight of the ingoing cement grout. As soon as the required calculated quantity of cement grout has been introduced, asecond wooden plug fitted with a leather cupped gasket and a 59 leather disc, is inserted into the casing, and

the plug or barrier forced to the bottom of the drill hole, together with the cement grout, the'cement grout passing out the side or out through openings in the bottom plug and upward around the casing to the required height, together with the air which is retained between the cement grout and thetop plug. Due to the weight of the column of cement grout being greater than the column of mud or water between the casing and the drill hole, the top surface of the cement grout charge may be at a depth of feet or more down the casing, before the insertion of the second plug, thereby trapping a large quantity of air. This trapped air passing up and into the cement grout may be wholly or partly retained therein, whereby a, porous cement set may be obtained and in some cases the desired water-tight bond between the casing and the drill hole is not obtained, requiring another cementation.

Now, we have discovered that these ditfieulties may be overcome by the employment of a new and novel device comprising an airtight cementing head which may be, attached to the casing and the operation performed with the substantial exclusion of am Inside of the cementing head, a special plug or barrier provided with two leather or fabric cupped gaskets, is suspended by a controlling rod above two inlet pipes provided with suitable valves, by means of which controlled amounts of rotary mud, water and cement grout ma be separately introduced as required. lshe inside wall of the cementing head contains grooved channels extending the full length so that the air pressure will beequalized until the plug has been lowered to a point below the inlet pipes.

Arrangements are made so that when the calculated quantity of cement grout has been introduced into the casing, the plug or bar rier may be disconnected and quickly lowered by first withdrawing a cotter pin and then imposing a manual downward pressure on the handle of the control rod, after which the plug is forced to the bottom of the casing by hydraulic pressure. 7

With the foregoing preliminary explanation, the preferred embodiment of our invention will now be more fully explained by reference to the accompanying drawing.

Figure 1 shows a sectional elevation of the complete assembled cementing head and plug in place before the cementing operation.

Figure 2 is a sectional view taken on the line A--A of Figure 1 looking in the direction of the arrows.

Figure 3 is a sectional View taken on the line BB of Figure 1 looking in the direction of the arrows.

In the drawing, 1 represents an annular tube of steel having threaded ends, one end being connected to a coupling 2 at the bottom and the other end to a casing head cap 9. The coupling 2 is screwed into well casing 33. The cementing head 1 is provided with two inlet pipes 3 and 5 controlled by valves 4 and 6. 12 represents the plug or barrier inthe top of the cementing head 1 attached to controlling rod 21. The controlling rod 21 is provided with two openings, 22 and 23, through which a cotter pin 24 may be inserted to hold the controlling rod in place. A casing head cap 9 is attached to the cementing head 1 by means of a screw joint. A pipe 7 controlled by the valve 8 is connected to the casing head cap 9. The controlling rod 21 passes through a stuffing box 10 and is connected to the plug 12 by a coupling 11. The barrier or plug 12 is provided with two leather cupped gaskets 14 and 14 so that an air tight connection may be had between the plug and easing wall when the plug is below the inlet pipes 3 and 5. The top leather cupped gasket is held in place by means of a plate or disc 18 and a lock nut 19. A rod 17 provided with a lock nut 19 and a washer 18' holds the leather cupped gasket 14' and the lower section of the plug 15, in place. 16 represents a grooved or furrowed passageway for the air to pass when the plug is being lowered, so as to maintain the same pressure above and below the plug since a reduced pressure is produced by the column of cement receding down the casing, to a depth of 50 feet or more. I

Figure 2 which, as described above, is a section on the line A A of Figure 1, shows the grooved channels 16 on the inside walls of the cementing head.

Figure 3 which, as described above, is a section on line B B of Figure 1 through the lower part of stuffing box '10, shows the control rod 21 connected to the plug 12 with the square fittings 10 and 11 to prevent the plug 12 from turning when it is disconnected.

The operation of the apparatus just described is as follows:

In the drilling of oil or gas wells, as soon as the drill hole approaches a productive zone, the water formations are definitely lo-- cated by core drilling, after which the casing is lowered to within a few feet of the bottom of the drill hole, and the quantity of cement i grout calculated to fill the space between the The drill hole is usually full of rotary mud employed in the drilling operation and the end of the casing is provided with a casing shoe and a float or check valve, so as to prevent any fluid from entering the casing through the bottom, thereby acting as a seal after the introduction of the cement grout. Water or mud is introduced into the casing at the top While the casing is being lowered into the drill hole, in quantities suflicient to cause the casing to sink into the mud at the desired rate of speed. After the casing has been lowered to within a few feet of the bottom of the drill hole, the cementing head 1 is connected to the top of the casing 33 by the collar 2. The plug or barrier 12 suspended by the control rod 21 is placed in position in the cementing head, this position being maintained by the cotter pin 24. Rotary mud, which is employed for the drilling operation, is then introduced into the casing through pipe 5 controlled by the valve 6, the pipe 5 leading to apump and a source of mud not shown. The casing 33 is filled with mud and a circulation of the mud maintained through the casing and out through the space between the casing and the drill hole to a storage, for a period of time sufiicient to clear the space between the drill hole and the casing. When the specific gravity of themud leaving the space between the casing and the drill hole is substantially the same as the specific gravity of the mud within the casing, the mud circulation is discontinued, and a rapid flow of water is introduced through the same pipe 5 controlled by the same valve 6, the pipe 5 leading to a pump and water supply not shown, which may be the same pum employed in the circulation of the mud as lieretofore described.

As soon as a sufficient supply of water has been introduced into the casing 33 to wash the mud off the walls of the casing and serve as a barrier between the mud and the cement grout, the introduction of water is discontinued and valve 6 is closed. Immediately thereafter, valve 4 is opened and a pumpable water mixture of Portland cement, which we term cement groutfi 'is introduced into casing 33, passing throughthe pipe 3 which leads to a pump and source of supply not shown. A rapid flow of cement grout into casing 33 is maintained until the calculated quantity has been introduced... immediately following the introduction of the cement grout, the valve 4 is closed and plug "12 is disconnected and lowered to a point below the inlet pipes 3 and 5. The plug 12 is lowered by withdrawing the cotter pin 24 employing a manual pressure to the top of the control rod 21, after which valve 6 is opened and mud is introduced through the ipe 5 in sufiicient quantities and under sufclent pressure to force the plug 12 by hydrostatic pressure to the bottom of the casing ,casing and the drill hole to the desired height.

a float or check valve and around the casing to the required height. Af-

passing through thence upward 33, the cement grout charge ter the plug 12 has reached the bottom of 1 the casing 33, which is noted by a sudden increase in pressure on the charging line 5, valve 6 is closed and the hydrostatic pressure of the mud column is maintained on the plug until the cement grout has set and hardened to the require-d degree, after which a water test is made and drilling operations continued by methods known in the art.

' attaching the casing head to a well casing, 21'

While the apparatus herein described is Well adapted for carrying out the object of the present invention, it is to be understood that various modifications and changes may be made without departing from the spirit of the invention, and'the invention includes all such changes and modifications as come withways extending longitudinally along the inside wall of the casing, a metal cap closlng one end ofthe casing, means for attaching the casing head to a well casing, a mecham- -cally controlled slidable plug suspended within said casing by a controlling rod with means for disconnecting the controlling rod from the plug, said controlling rod passing through a stufing box in the metal cap, and controlled inlet means into the casing head.

3. A well cementing apparatus, compris-- ing, a capped length of easing withgrooved passageways extending longitudinally along the inside wall of the casing, a mechanically controlled slidable plugwith gasket means v,betweenthe wall of the casing and the plug,

a controlling rod attached tosaid plug with means for disconnecting and adjusting the plug at desired levels, means for disconnecting the controlling rod from the plug, and controlled inlet'means into the casing head;

4. A well cementingapparatus comprising, a capped casing head, means for attaching the casing head to a well casing, a slidable plug in said casing head above valved inlets plug in said head above valved inlets for admitting mud, water and cement grout into the casing head, said plug having upper and lower cupped gaskets, vertical \grooves inside the casing head for equalizin fluid pressure above and below the plug, an means for disconnecting and controllably lowering the plug into the well casing by a manually oper-' ated rod passing through a stufling box in the cap, said rod being adapted todisengage a screw connection on top of the plug.

In testimony tures.

HORTON H; DIEVENDORFF. SIDNEY O. BARTON.

whereof we aflix our signa- ZOO lbs

for hand, water and cement grout, vertical ooves inside the casing head for equalizing l iid pressures above'and below the plug, an mechanical means for disconnecting and controllabl lowering the plug to a mined stance below the valved inlets. a

5. A well cementing apparatus, comprising, a capped metal casing head, means for predeter-

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