US1994072A - Cementing plug - Google Patents

Description

March 12, 1935. J. A. HARDCASTLE CEMENTING PLUG Filed May 19 1952 2 Sheets-Sheet 1 March 12, 1935'. J. A. HARDCASTLE 1,994,072

CEMEN'IING PLUG Filed May 19} 1932 2 Sheets-Sheet 2 /////X I a Patented Mar. 12, 1935 v UNITED STATES PATENT OFFICE CEMENTING PLUG Jasper A. Hardcastle, Angleton, Tex. Application May 19, 1932', Serial No. 612,213 7 Claims. (01. 166-1) This invention relates to a cementing plug. numeral 1 designates a pipe to be cemented in An object of the inventionis to provide a plug a well and having the guide shoe 2 on the. of the character described specially designed lower end thereof having the lower end. opening foruse in/ lowering a load of cement down 3. 5 through a pipe in a well bore for cementing The cement to be lowered is located between 5 around the lower end of said pipe. the upper "and lower plugs 4, 5 and fluid pres- Another object of the invention is to provide a' sure then applied to'force said plugs and the cementing plug which is of such special formaload between them down through said pipe. tion that there will be no leakage past/the plug The lower plug 5 has an axial passageway 6 l0 and between the plug and pipe as the load of therethrough whose upper end may be closed by cement is lowered. v an upwardlly opening valve '7 whose stem 8 ex- Another object of the invention is to provide 3, tends down through said passageway and on becementing plug of such formation that it will neath the lower plug. When the lower end of not be liable to hang in or be injured by the pipe the stem 8 lands on the lower end of the shoe through which it is being lowered. 2 the lower plug 5 will move on down and the 15 Another object of the invention is to provide a valve 7 will be lifted and the cement may pass on cementing plug having its lower end so shaped down through said lower plug and out of the that it will form a close fit with the float shoe, opening 3 and up around the lower end of the at the lower end of the pipe to be cemented so pipe where it is-allowed to set to cement said as to close the passageway through said shoe pipe in the well, all as shown in Figure 6. 20 when the load of cement has been discharged. The method of lowering the load of cement With the above and other objects in view this and of discharging the same into the bore invention has particular relationto certain novel around the pipe forms no part of thepresent features of construction, arrangement of parts invention, the novelty residing in the type of '25 and use an example of which is given in this plug employed. The plugs 4, 4a, 4b,-may be 45 pipe having a float shoe on the lower end, therespecification and ilustrated in the accompanyformed of rubber, or similar yieldable material lng drawings, wherein: I and their upper and lower ends are flared form Figure 1 shows a vertical sectional view of a ing the annular lips 9, 10. The plug 4 has the pipe to be cemented with upper and lower plugs deep annular end chambers 11, 12, concentric therein with a load of cement between them. therewith and the plug 4a has the upper and 30 Figure 2 shows a side elevation partly in seclower end cavities 13, 14, while the plug 4b is tion of one form of plug. solid throughout except at its flared ends. Lhe

Figure 3 shows a similar view of another form fluid, under pressure in the chambers 11, 12 or of the plug. in the cavities 13, 14 will expand the corre- Figure 4 shows a vertical sectional view of a sponding ends of the plugs out closely against bottom plug illustrating the invention. the walls of the pipe to prevent leakage past Figure 5;.shows a cross sectional view taken said plugs. on the line 5-5 of Figure 1. The plugs 4, 4a, 41), may have a plurality Figure 6 shows a vertical sectional view of a of external annular grooves 15, 16 therearound pipe to be cemented, having a guide shoe thereand undercut to present the external, annular, 40 on and cementing plugs of the particular deupwardly directed lip 17 and the annular downsign herein described discharged, their lower wardly directed lips, 18, 18. The pressure fluid positions showing the load of cement discharged. .above the plug passing by the upper lip 9 will Figure '7 shows a vertical sectional view of a enter the groove 15 and press the lip 17 outward- 1y to maintain a close seal with the pipe and the 45 fluid under pressure beneath said plug and which may escape up past the lower lip 10 will enter one or both of the grooves 16 and press the lips 18 out against the pipe to maintain atight seal.- This general type of plug may have a core of wood, concrete, or the like as hereinafter described and shown in FigurelO. Referring now more particularly to the draw- The bottom plug 5, as shown, has a tubular lngs wherein like numerals of reference desigconcrete core surrounded by a rubber sheath 'nate similar parts in each of the figures, the having the flared upper and lower annular lips of, and showing a special type of plug designed to close the passageway through said shoe.

Figure 8 shows a similar view showing the plug closing said passageway. 50 Figure 9 shows a cross sectional view taken on the line 9-9 of Figure 7, and Figure 10 shows still another form of upper plug.

19, 20 and the external, longitudinal ribs 21 which form guides to prevent the plug from.

hanging in, or being injured by the joints between the sections of the pipe 1. The rubber sheath around the core of the plugs 5, has an internal, annular ledge 22 to support said core therein.

In'some cases only an upper plug will be employed to force the load of cement downwardly through the pipe. Either of the for-ms shown in Figures 1, 2 and 3 may be used for this purpose or either of the forms shown in Figures 7 and may be used.

In lowering the pipe 1 into the bore a float shoe as 23 may be attached to the lower end of the pipe which may be closed against the inlet of fluid from the well so that the pipe will be partly sustained by said fluid and thus floated in. The shoe 23 may have a passageway 24 axially therethrough whose upper end is reduced forming a valve seat 25 which may be closed by the valve 26 insaid passageway beneath and which is retained in place by a retainer rod 27 across the passageway beneath said valve. As the pipe 1 is lowered through. the fluid in the well. the valve 26 will be held against the seat 25 by the pressure of the fluid and said fluid will be prevented from entering the pipe. When the pipe is lowered and located in thebore fluid may be forced down through the pipe and through the passageway-24. The shoe 23 may be formed of an outer metallic shell with a concrete plug therein so that the shoe may be readily drilled out when it is desired to deepen the bore beneath.

When it is desired to cement around the lower end of the pipe, as shown in Figure 8 a" load of cement may be introduced into the upper end of said, pipe after the pipe is located in the,bore and a solid plug, as 28, or 29 may then be inserted into the pipe above said load and the plug and cement ahead of it then forced down by fluid pressure from above and when the cement reaches the bottom of the pipe it will pass out through the passageway 24 into the bore around said pipe, as shown in Figure 8 where the cement is allowed to set. The plug 28, or 29, as the case may be will finally land on the float shoe 23, and said plug has a downwardly projecting nose 30 which flts into the flared upper end of the passageway 24 to completely close said passageway so that the pressure fluid above, even though it might escape past the plug, can not pass downwardly through the passageway 24 and contaminate or wash away the cement. When said plug lands on the float shoe the pump for delivering said pressure fluid will be stalled to indicate to the operator that the job has been completed.

The plugs 28, 29 may be of solid rubber or may be formed with concrete cores. The external surface of the plug 28 is the same as that shown in Figure 5 while the external surface of the plug 29 is the same as that shown in Figures 2 and 3.

The drawings and description disclose what are now considered to be preferred forms of the invention, by way of illustration only, while the broad principle of the invention will be defined by the appended claims.

What I claim is:

1. A cementing plug having a rigid core and a one piece sheath around and extending each way beyond the core and formed of yieldable material and having annular end lips formed integrally therewith, the lip at one end'facing a direction the opposite of that of the other end lip, saidsheath also having intermediate annular lips around the sheath which face one in a direction the opposite of that of another.

2. A cementing plug of cylindrical contour and having annular end lips formed of yieldable material and external, lengthwise, ribs spaced apart around the plug.

3. A cementing plug having a core formed of rigid material, a sheath around the core form- 'ed of resilient material and having annular end lips which face in opposite directions, and annular, intermediate lips around the sheath which face in opposite directions.

4. A cementing plug having a tubular core of rigid material and a sheath around the core formed of resilient material and having annular,

outwardly tapered, end lips which face in opposite directions, and an annular inside abutment in the sheath against which one end of the core abuts.

5.. In a cementing plug, a hollow sheath formed of resilient material having a smooth interior and having annular, oppositely directed external lips, and an annular inside abutment in the sheath adjacent one end thereof.

6. A cementing plug having annular end lips formed integrally therewith and tapering to thin edges and facing in opposite directions one end of the plug having a cavity of greater depth than Width. I

7. In a cementing plug, a hollow sheath formed of resilient material, having a smooth interior and having annular oppositely disposed external lips and an inside abutment in the sheath adjacent one end thereof. I

JASPER A. HARDCASTLE.

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