US3006415A - Cementing apparatus - Google Patents

Description

Oct. 31, 1961 E. BURNS ETAL CEMENTING APPARATUS 5 Sheets-Sheet 1 Filed July 8, 1958 INVENTORS .EZPM/N Si Bye/vs PefegQFle/ ,46E/VT' l uilf i 4 Q 3 228 1 A;

Oct. 31, 1961 Filed July 8, 1958 E. BURNS ET AL CEMENTING APPARATUS 3 Sheets-Sheet 2 INVENTORS Oct. 31, 1961 E. BURNS ETA].

CEMENTING APPARATUS 5 Sheets-Sheet 3 Filed July 8, 1958 INVENTORS I? WIN 5'. Bap/vs BY refer JF/ ,4

56,415 Patented Get. El, 1961 3,006,415 CEMENTING APPARATUS Erwin Burns, Los Angeles, and Peter .F. Fiei, Downey, Calif. (both Burns Tool (30., 8346 Salt Lake Ave, Bell, Calif.)

Filed July 8, 1958, Ser. No. 747,223 Claims. (Cl. 166156) This invention relates to oil well equipment and is more particularly concerned with an improved well cementing apparatus.

It is common practice in the course of drilling a well to insert strings of casing of diminishing diametric extent into the well bore as drilling of the well progresses. This is accomplished by telescopically engaging the next string of casing of reduced diameter into the preceding larger string of easing, lowering it into the well through the preceding string or strings of casing by means of a setting tool at the lower end of a string of drill pipe, so that it depends into the well bore below the lower terminal end of the preceding string of casing, and then suspending it from the lower end of said preceding string of casing by means of a casing hanger, which hanger is engaged at the upper end of the string of new casing and which is actuated into gripping engagement with the said preceding string of casing by means of the setting tool. After the new casing is suspended in the well in the manner set forth above, the drill pipe and setting tool are pulled or removed from the well.

It is also common practice, after a new string of casing is suspended in a well in the above manner, to cement it in fixed position in the well by introducing a slurry of cement into the annulus occurring between the well bore and the exterior of the new casing. This cementing operation is accomplished by providing a float collar in the new string of casing at a desired position intermediate its ends and then running a cementing tool, on the lower end of a string of drill pipe, into the new casing and introducing the cement into the casing under pressure and so that it flows downwardly through the float collar and the casing and into the well bore about the said casing.

The ordinary float collar involves a tubular body interposed in the string of casing to be set and is provided with a check valve mechanism adapted to prevent the upward flow of fluid therethrough. The float collar is intended to prevent the cement introduced into the well from flowing back up through the casing when the pressure above the float collar is reduced and/or when the cementing tool and drill pipe carrying it are removed or withdrawn from the well. The valve mechanism is mounted in the body of the ordinary float collar in a core of drillable material, such as cement, and so that when the cementing operation is completed, the new string of casing can be opened by drilling through the float collar and the cement occurring in the casing below the collar.

The ordinary cementing tool involves a tubular mandrel secured to the lower end of the drill pipe string to which it is related and carries a plurality of cup-like rubber packers, which packers are adapted to engage and seal the interior of the new casing and prevent the cement introduced into the casing through the drill pipe and the mandrel from flowing upwardly in the casing around the drill pipe.

Upon completing the cementing operation and before the cementing tool is pulled, it is common practice to insert a wiping plug into the top of the drill pipe and urge it therethrough with a suitable circulating fluid and in a manner to urge all of the cement through and out of the drill pipe. The wiping plug is simply left in the well and is ground up and removed therefrom by the subsequent dn'lling operation which is performed to open the newly set casing.

In the ordinary cementing operation, as set forth above, the valve mechanisms in the float collars become worn and damaged by the cement which is urged therethrough and frequently fail to adequately seal and prevent the back flow of cement in the well.

An object of the present invention is to provide a novel well cementing apparatus which apparatus is associated and connected with a casing hanger and setting tool therefor, and need not be run into the well separately and after the new casing has been set.

Another object of the present invention is to provide an apparatus of the character referred to including a novel cementing tool having a casing wiping plug releasably secured to the lower end thereof and adapted to engage with the float collar.

A further object of the present invention is to provide a locking means adapted to secure the casing wiper plug to the float collar and so that it cannot be urged upwardly in the casing by the exertion of fluid pressure from below the float collar, after it has once been fully engaged with the collar.

It is another object of the present invention to provide a casing wiping plug having a suitable seat adapted to cooperatively receive a drill pipe wiping plug.

Still another object of the present invention is to provide a novel drill pipe wiping plug having sealing means therein to engage and seal in or with the casing wiping plug.

Another object of the present invention is to provide an apparatus of the character referred to having locking means between the casing wiping plug and the drill pipe wiping plug to prevent disengagement of the plugs upon the exertion of fiuid pressure from below the float collar with which they are related.

It is an object of the resent invention to provide an apparatus of the character referred to which is both easy and economical of manufacture and which is both highly effective and dependable in operation.

The various objects and features of our invention will be fully understood from the following detailed description of a typical preferred form and application of our invention, throughout which description reference is made to the accompanying drawings, in which:

FIG. 1 is a longitudinal view of the apparatus that we provide showing it engaged in a well preparatory for operation and showing certain parts thereof in section to better illustrate the construction.

FIG. 2 is an enlarged, detailed, sectional view of the apparatus shown in FIG. 1 and showing certain parts thereof in an actuated position.

FIG. 3 is a perspective view of the drill pipe wiping plug that we provide.

FIG. 4 is a perspective view of the casing wiping plug that we provide.

FIG. 5 is a view similar to FIG. 1 and showing the apparatus in another stage of operation.

FIG. 6 is a view similar to FIG. 2 illustrating the apparatus in another stage of operation, and showing the drill pipe wiping plug entering the apparatus.

FIG. 7 is a transverse sectional view taken as indicated by line 7-7 on FIG. 6.

FIG. 8 is a transverse sectional view taken as indicated by line 88 on FIG. 6.

FIG. 9 is a transverse sectional view taken as indicated by line 9-9 on FIG. 6.

FIG. 10 is a longitudinal sectional view showing the apparatus after the cementing operation is completed and showing certain parts of the apparatus being withdrawn from the well.

FIG. 11 is an enlarged, detailed, sectional view of a portion of the construction and relationship of parts illustrated in FIG.

. FIG. 12 is a view similar to FIG. 1 and showing the apparatus of the present invention related to a float shoe engaged at the lower terminal end of the casing.

The cementing apparatus A provided by the present invention is adapted to be engaged in the lower end of a typical well structure W, and in the case illustrated is shown engaged in the lower end of a well casing 10 to depend therefrom and into the well bore 11 occurring below the casing 10.

The apparatus A is shown as including, a casing hanger B, which hanger is related to a setting tool C secured to the lower end of a string of drill pipe S, a casing string D carried by the hanger B to depend therefrom and extend freely into the well bore 11, a float collar E engaged in the casing string D to occur at a point between the ends thereof, a cementing tool or packer F carried by the setting tool to depend into the casing string D, a casing string wiping plug G releasably carried by the cementing tool and engageable with said float collar and a drill pipe wiping plug H adapted to be engaged in the string of drill pipe to shift longitudinally therethrough and to engage and seat in the casing string wiping plug G.

The casing hanger B provided by the present invention is the same as that disclosed in the United States patent issued to Frank C. Boyd, Erwin Burns and Ford A. Pilgrim, on January 14, 1951, No. 2,228,503, and entitled Liner Hanger. The hanger B is shown as involving, generally, an elongate, vertically disposed, tubular body 12, a plurality of circumferentially spaced wickered slips 13 slidably carried in radially outwardly and upwardly inclined recesses 14 in the exterior of the body. A suitable spring means 15 is provided in the body adjacent the lower end of each slip 13 and is adapted to normally yieldingly urge the slip related thereto upwardly and outwardly relative to the body and into wedging and gripping engagement with the interior of the casing 10 in the well W. The upper end of the body 12 is internally threaded as at 16 to cooperatively receive a part of the setting tool C, as will hereinafter be described, while the lower end of the body is internally threaded as at 17 to threadedly receive the upper terminal end of the casing string D.

The setting tool C, which tool is designed specifically to control the actuation of the slips 13 of the hanger B is also disclosed in detail in the above-mentioned Boyd et al. patent, No. 2,228,503, and involves, generally, an elongate, vertically disposed, tubular kelly 18 adapted to normally extend through the hanger body and to project from the opposite ends thereof, and an externally threaded releasing nut 19 engaged on the kelly to establish rotary driving engagement therewith and slidable longitudinally thereof. The nut 19 is adapted to be threadedly engaged in the threads 16 in the upper end of the hanger body 12 and is provided with circumferentially spaced, depending fingers 20 about its periphery, which fingers are adapted to normally engage the tops of the slips 13 and hold them down in their unactuated position.

The upper terminal end of the kelly 18 is provided with an internally threaded enlargement 21 and into which the lower end of the drill pipe string S is engaged, while the lower end of the kelly is provided with an internally threaded enlargement 22 and in which a suitable pipe section pup joint 23 of desired length is engaged and to which the cementing tool is related.

It is to be understood that the details of construction of the hanger B and the setting tool C disclosed in the drawings and briefly described above can vary widely without materially afiecting the novelty of the present invention now under consideration.

The casing string D carried by the hanger B and depending therefrom and into the well bore 11, is a simple stnng of casing made up of two or more stands of casing pipe and in practice can vary in length as circumstances require. The upper terminal end of the string D' is engaged or made up with the threads 17 in the lower end of the hanger body 12 and so that it is suspended there from. The lower end of the string D is shown as being closed by a conventional guide shoe 24, which shoe is shown as having a core 25 of soft, drillable material, such as cement. The core 25 of the particular shoe 24 illustrated in the drawings is provided with a suitable passage 26' extending therethrough, which passage is adapted to pass cement flowing downwardly through the string of casing into the well bore 11.

It is to be understood that, in practice, the lower end of the casing string D could be closed by an imperforate guide shoe 24' that is, a guide shoe without a flow passage extending throughout it as shown in FIG. 10; or, if desired, by a float shoe that is, a unitary combined guide shoe and float collar construction, as illustrated in FIG. 12 of the drawings.

The float collar E that we provide can be engaged between the opposed ends of adjacent lengths of casing in a casing string or can, as illustrated, be engaged with the lower end of such a string and connect with a guide sleeve, or the like, at its lowermost end. In the drawings, the collar is shown as including an elongate, vertically disposed tubular body 26 internally threaded at its upper end, as at 27, to receive the lower end of the stand of casing occurring above it and externally threaded at its lower end as at 28, to engage in the upper end of the guide shoe 24 occurring below it.

Disposed within the bore 29 of the body 26 and spaced intermediate the ends therof is a plug or core 36 formed of an easily drillable material such as cement. The plug 30 is provided with a central longitudinal flow passage 31 entering it from its upper end and continuing downwardly to establish open communication with a central downwardly opening valve chamber 32 provided in its lower portion. A suitable spring-loaded check valve mechanism 33 is engaged in the chamber 32 in the float collar and is adapted to control the flow of fluid through the collar. The upper end of the plug 30 is provided with a downwardly and inwardly inclined seat 34, which seat is concentric with the longitudinal axis of the collar.

A suitable, radially inwardly opening channel 35 is provided in the bore 29 of the float collar body 26, adjacent the top or the upper end of the plug 30 therein and in which a suitable annular snap ring 36 is engaged. The snap ring 36 is adapted to project radially outwardly into the bore in the body and establish a downwardly facing annular shoulder 37 in the collar body and with which the casing wiping plug G is adapted to engage and lock, as clearly illustrated in the drawings and as will hereinafter be described.

The valve mechanism 33 engaged in the chamber 32 of the float collar is shown as including, generally, a tubular valve cage 38 molded into the core 30 to occur in and/or cooperate with the core to define the chamber 32, and having a central inlet opening 39 in its upper end to communicate with the flow passage 31, a radially inwardly and upwardly inclined valve seat 40 in the upper end of the cage concentric with the opening 39, a spherical valve member 41 arranged within the cage and engageable on the seat 40, a retaining spider or web 42 at the lower end of the cage and a compression spring 43 between the cage and the valve member and normally yieldingly urging the valve member upwardly into sealing engagement on the seat 40.

In the particular case illustrated, the float collar E is provided with a plurality of circumferentially spaced, radially disposed ports 44, which ports establish open communication between the chamber in the valve, below the seal 40 therein and the annulus 45 occurring between the collar and the well bore 11. The ports 44 are adapted to conduct a portion of the slurry of cement introduced into the collar into the annulus 45 above the lower end of the casing string.

The particular float collar E illustrated and described above is only illustrative of one particular type of float collar construction that can be employed and distinguishes from standard or conventional float collar constructions by the provision of the inclined seat 34 at the upper end of the plug or core 36 therein and by the provision of the snap ring 36, which ring establishes the annular shoulder 37 in the body of the collar above the plug 30 and with which the casing Wiping plug G is adapted to engage and lock.

It will be apparent that the float collar E is such that it will freely pass a slurry of fluid cement downwardly through the casing string D, but is such that it will normally prevent or check the upward flow of the slurry through the casing occurring above the collar.

In practice, the valve mechanism 33 in the float collar E is made or formed of a relatively soft, easy todrill material, so that upon completion of the well cementing operation, it can be easily and conveniently removed by a simple drilling operation. As a result of the above, that is, as a result of the soft nature of the valve mechanism, the seat 49 and the ball 41 thereof frequently become damaged and worn as the result of the passage of cement therethrough and will not properly seat and seal when such is desired.

The cementing tool F provided by the present invention is a typical cementing tool and includes an elongate, tubular body or mandrel 46 and a plurality of vertically spaced, downwardly disposed, annular packing cups 47. The body or mandrel of the cementing tool is threadedly engaged on the lower end of the pup joint 23 fixed to and depending from the kelly 18 of the hanger setting tool C and so that it depends therefrom and freely into the casing string D. The packing cups 47 carried by the mandrel 46 establish sliding sealing engagement with the interior of the casing string D to wipe and clean the casing when the tool is lowered into engagement therein and to positively prevent fluid in the casing string, below the cementing tool, from flowing upwardly therein.

In practice, the cementing tool F provided or employed in the apparatus of the present invention can vary widely in form and construction without in any way aifeoting the novelty and operation of the apparatus.

In light of the above, we will not burden this specification with further detailed description of the construction of the cementing tool illustrated in the drawings.

The casing string wiping plug G that we provide is an elongate, vertically disposed member formed of rubber and is adapted to be normally carried by the cementing tool F at the lower end thereof and to engage and wipe the interior of the casing string D, as the cementing tool F is shifted longitudinally therein.

The plug G is shown as having a cylindrical rubber body 50 formed about a soft metal tubular core 51. The upper and lower terminal ends of the body 50 are provided with radially outwardly and upwardly inclined casing engaging wiping flanges 52 and 53. The central portion of the body 50 is provided with a plurality of flat, horizontally disposed and vertically spaced wiping flanges 54.

The lower wiping flange 53 is inclined at an angle complementary with the angle of the seat 34 at the top of the core in the float collar E and is adapted to be urged into sealing engagement therewith as will hereinafter be described. The uppermost wiping flange 52 establishes an upwardly disposed cup and is adapted to prevent fluid in the well above the plug from flowing downwardly around the plug as will hereinafter be described.

In addition to the foregoing, the casing string wiping plug G is further provided with an upwardly projecting cylindrical boss 55 formed of a soft easily drilled metal and threadedly engaged in the upper end of the tubular core 51 as at 56. The boss 55 has a longitudinally disposed bore 57 communicating with the interior of the core 51 and has an upwardly opening round socket 58 of larger diameter than the bore and in which the drill string wiping plug H is adapted to be engaged. Within the socket and located at a predetermined position intermediate its ends is provided an annular, radially inwardly opening channel 59 in which an expansible snap ring 60 is engaged. The snap ring 60 engaged in the channel in the boss projects radially inwardly into the socket and establishes a downwardly facing stop shoulder therein. The snap ring 60 is adapted to yieldingly pass a portion of the drill pipe wiping plug H and to thereafter retain the plug H in engagement with the plug G as will hereinafter be described.

In addition to the foregoing, the boss 55 of the plug G is provided with a radially outwardly opening groove 61 about its exterior, which groove is adapted to receive parts of an adapter 62 provided to releasably secure the plug G to the cementing tool F.

The adapter 62 mentioned above is a simple, elongate, tubular member externally threaded at its upper end as at 63 and provided with a downwardly opening socket 64 in its lower end. The upper end of the adapter is threadedly engaged in the lower end of the cementing tool to depend therefrom. The boss 55 of the plug G is slidably engaged in the socket in the lower end of the adapter and is releasably maintained engaged therein by a plurality of cincumferen-tially spaced shear pins 65 carried by the adapter and projecting radially inwardly into the grooves 61 in the boss.

It will be apparent that when the cementing tool is lowered into the casing, the plug G carried thereby serves to wipe the casing in advance of the packer cups 47 of the tool F, thereby supplementing the wiping action of the said cups and also displacing the major quantity of abrasives and the like, in the path of the packers and which would otherwise adversely affect the packers.

The drill pipe wiping plug H provided by the present invention is a so-called bomb-type plug and is adapted to be entered into the upper end of the drill pipe S to follow a slurry of cement therein and to be urged downwardly through the pipe S, hanger setting tool C and cementing tool F to wipe and clean the cement therefrom. The plug H is also adapted to be urged into engagement with the casing wiping plug C by the application of fluid pressure thereon, to urge the plug H out of engagement with the adapter 62 and into engagement with the float collar D, so that it seals and locks therewith and prevents fluid from flowing upward-1y through the plug G.

The plug H is shown as including an elongate, vertically disposed, cylindrical head 70 formed of a soft easy to drill metal and an elongate, vertically disposed rubber body 71 projecting upwardly from the head. The rubber body 71 of the plug H has a pair of flat, radially outward-1y projecting, flexible flanges 72 at its lower end portion, which flanges are adapted to engage the inner wall or" the drill pipe to wipe it as the plug is urged therethrough. The upper portion of the body 71 is provided with a radially outwardly and upwardly inclined flange 73, which flange engages the inner wall of the drill pipe and which establishes an upwardly opening cup on which the propelling or motive fluid occurring above the plug can act.

In the case illustrated, the flange 73 is spaced a predetermined distance from the top end of the body and so that when it is compressed circumferentially within the drill pipe, the upper portion of the body backs up and prevents the flange from buckling and failing to maintain complete circumferential wiping and sealing contact with the interior of the drill pipe.

The cylindrical head 70 of the plug H is provided with a downwardly disposed rounded nose 74 at its lower terminal end and is provided with a radially outwardly projecting flange 75 intermediate its ends. The nose 74 of the plug H is adapted to seat on the bottom of the socket 58 in the boss 55 of the plug G, when the plug H is fully engaged in the construction. The flange 75 on the head of the plug H is provided with an upwardly and radially outwardly inclined shoulder 76 at its bottom or lower end and a flat, horizontally disposed shoulder 77 at its upper end. When the plug H is urged into engagement into the socket 58 in the plug G in the manner set forth above, the flange 75 is urged past the expansible snap ring 60 in the socket and is thereafter maintained engaged in the socket by the snap ring.

In addition to the foregoing, the head 70 of the plug H is provided with a radially outwardly opening channel 78 below the flange 75 and in which an O-ring seal 79 is engaged. The O-ring seal 79 is adapted to establish sealing engagement with the wall of the socket 58 in the plug G when the plug H is fully engaged therein.

With the above relationship of parts and when the plug G if fully engaged in the float collar E and the plug H is fully engaged in the plug G, it will be apparent that fluid occurring below the float collar E is positively prevented from flowing upwardly through the apparatus even when the valve mechanism 33 of the float collar fails to establish an adequate seal.

In operation, the apparatus of the present invention is assembled and lowered into the Well structure W in the manner illustrated in FIG. 1.

When the apparatus is properly oriented in the well, the hanger B is actuated in the manner illustrated in FIG. 2, by rotating the releasing nut 19 of the setting tool C out of engagement therewith, as by rotation of the drill string and setting tool kelly 18.

After the hanger B is set and the casing D is suspended in the well, cement is urged downwardly through the drilling string and the apparatus, through the float collar E and thence into the annulus 45 between the apparatus and the well bore 11.

During or following the introduction of cement into and through the construction, the drill string S can be lowered to urge the casing wiping plug G into locked sealing engagement with the float collar E as clearly illustrated in FIGS. and 6 of the drawings.

Upon completion of the introduction of cement into the drill pipe string, the drill string wiping plug H is introduced into the drill string S and is urged or pumped downwardly therethrough and into the apparatus in a manner to advance all of the cement occurring before it through the apparatus and so that it establishes locked sealing engagement in the casing wiping plug G.

Upon further application of pressure upon the plug H, after it is engaged in the plug G, the shear pins 65 of the adapter 62 yield and the plug G is released from engagement with the adapter.

The above releasing of the plug from the adapter 62 can be accomplished before the plug G is engaged in the float collar E, or it can be accomplished after the plug G is engaged in the float collar E, as by elevating the drill string and the adapter related thereto, a short distance, when the required fluid pressure is exerted on the plug G through the plug H to shear the pins 65.

If the plug G is released from the adapter before it is engaged with the float collar E, the fluid acting upon it will urge it into the desired sealing and locking engagement with the collar.

When the plug G is released from the adapter, the fluid under pressure employed to release it acts between the packer cups 47 and the upper wiping flange 52 of the plug G to hold it down, in engagement with the collar and to supplement the locking action afforded by the said flange 53 and ring 36.

After the plug G is released from the adapter in the manner set forth above, and in engaged in the float collar E, the cementing operation is finished and the drill string S, setting tool C, cementing tool F and adapter 62 are withdrawn from the well structure in the manner illustrated in FIG. 10 of the drawings, leaving the remainder of the apparatus in the Well and in the manner clearly illustrated in FIG. 10 of the drawings.

The cementing operation thus completed, the plugs G and H, the core 30 and valve mechanism 33 of the float collar E and the cement in the casing string D below the collar E can be drilled out and removed from the well structure in any suitable manner to open the newly suspended and cemented in casing string D.

It is to be understood that in practice the apparatus could be run into a well independently of the hanger and setting tool in which case the cementing tool is connected directly to the lower end of the drill string.

It is also to be understood that the float collar could be eliminated and replaced by a float shoe engaged in the lower end of the casing string, and with which the plugs and cementing tool would cooperate in substantially the identical manner as set forth above. In FIG. 12 of the drawings, we have shown the apparatus including a float shoe E as set forth above and instead of a float collar.

It is still further to be understood that the apparatus is equally applicable for suspending and cementing in liners. In this set-up, the only distinction is that a liner hanger is employed in place of the casing hanger and a liner is substituted for the casing string. It will be observed however, that the above is more a substitution of terms than of structures so far as the instant invention is concerned.

In FIGS. 5 through 11 of the drawings, in which views cement has been introduced into the annulus between the casing and the well bore, we have omitted showing the cement which would occur within the apparatus for the purpose of clarity.

Having described only a typical preferred form and application of our invention, we do not wish to be limited or restricted to the specific details herein set forth, but wish to reserve to ourselves any modifications or variations that may appear to those skilled in the art and fall within the scope of the following claims.

Having described our invention, we claim:

1. A well cementing apparatus of the character referred to including, a fluid conducting float collar engaged in a string of casing depending into a well, said float collar including an elongate, vertically disposed, tubular body with an annular downwardly facing shoulder in its upper end portion, an annular core of easy to drill material in the body and having an annular radially outwardly and upwardly inclined seat adjacent opposing the said shoulder and a check valve mechanism in the core to check the upward flow of fluid therethrough, an elongate fluid conducting drill pipe string depending into the casing from the top of the well, an elongate vertically dis-Q posed fluid conducting tool fixed to the lower end of the drill pipe string to establish open communication therewith and carrying packers to slidably engage and seal in the casing, an elongate, vertically disposed tubular fluid conducting adapter engaged with and depending from a cementing tool and having a radially inwardly projecting shear pin in the lower end portion, a casing string wiping plug including an elongate, Vertically disposed body of flexible material having a tubular fluid conducting core and a plurality of vertically spaced, radically outwardly projecting flanges, the lowermost flange being upwardly inclined to cooperatively engage the seat in the float collar and adapted to be urged past the shoulder in the collar to establish locked engagement therebelow and an upwardly projecting cylindrical boss on the casing string wiping plug having an annular, outwardly opening channel about its periphery, a central upwardly opening socket with a cylindrical side wall and terminating in the boss to establish an annular bottom and an annular radially inwardly opening recess carrying an expansible snap ring in the wall of the socket and spaced above said bottom, said boss on the casing string wiping plug being normally engaged in the lower end of the adapter with the shear pin engaged in the channel therein and a drill pipe wiping plug having an elongate cylindrical head, and an elongate vertically disposed body of flexible material projecting upwardly from the head, the head having a radially outwardly projecting flange and a radially outwardly opening channel below the flange and carrying a sealing ring, the body having a plurality of vertically spaced, radially outwardly projecting flanges adapted to establish sealed wiping engagement in the drill string, said drill string wiping plug being insertable into the drill string at the top of the well and to be urged downwardly therein by fluid pressure to engage the casing string wiping plug so that the head thereof enters the socket in the casing string wiping plug to shut off flow therethrough and so that the head seats on the bottom of the socket, the O-ring seals on the wall of the socket and the flange on the head is urged past the snap ring in the socket to establish locked engagement therein.

2. A well cementing apparatus of the character referred to adapted to be related to a set casing in a well bore including, an elongate, fluid conducting drill pipe string depending into the fixed casing from the top of the well, a setting tool with a central, longitudinally shiftable, fluid conducting kelly fixed to the lower end of the drill string, a casing hanger releasably carried by the setting tool and adapted to be actuated into gripping engagement in the set casing by the setting tool, an elongate casing string fixed to the casing hanger and depending freely into the set casing, a float collar engaged in said casing string and including an elongate, vertically disposed, tubular body with an annular, downwardly facing shoulder in its upper end portion, an annular core of easy to drill material in the body and having an annular, upwardly disposed seat opposing said shoulder, an elongate, vertically disposed fluid conducting cementing tool connected to the lower end of the setting tool kelly to establish open communication therewith and including packing means to engage and seal in the casing string, tubular fluid conducting adapter engaged with and depending from the cementing tool and plug engaging means in the lower end portion thereof, a casing string wiping plug of flexible material having a fluid conducting passage extending therethrough, and a radially outwardly projecting flange adapted to cooperatively engage the seat in the float collar and adapted to be urged past the shoulder in the collar to establish locked engagement therebelow and an upwardly projecting cylindrical boss on the casing string wiping plug having a central, upwardly opening socket and lock means in the socket to engage a part of a drill pipe wiping plug, said boss on the casing string wiping plug being normally engaged in the lower end of the adapter and engaged by said plug engaging means, and an elongate, vertically disposed drill pipe wiping plug of flexible material having parts adapted to establish sealed wiping engagement in the drill string and a depending head, said drill string wiping plug being insertable into the drill string at the top of the well and to be urged downwardly therein by fluid pressure to engage the casing string wiping plug so that the head thereof enters the socket in the casing string wiping plug to shut off flow therethrough and so that the means in the socket establishes locked engagement therewith.

3. A well cementing apparatus of the character referred to adapted to be related to a set casing in a well bore including, an elongated, fluid conducting drill pipe string depending into the fixed casing from the top of the well, a setting tool with a central, longitudinally shiftable, fluid conducting kelly fixedto the lower end of the drill string, a casing hanger releasably carried by the setting tool and adapted to be actuated into gripping engagement in the set casing by the setting tool, an elongate casing string fixed to the casing hanger and depending into the well, a float collar engaged in said casing string and including an elongate, vertically disposed, tubular body with an annular, downwardly facing shoulder in its upper end portion, an annular core of easy to drill material in the body and having an annular radially outwardly and upwardly inclined seat opposing said shoulder, an elongate, vertically disposed fluid conducting cementing tool connected to the lower end of the setting tool kelly to establish open communication therewith and carrying packers to slidably engage and seal in the casing string, an elongate, tubular fluid conducting adapter engaged with and depending from the cementing tool and having inwardly projecting releasable plug engaging means in the lower end portion, a casing string wiping plug including an elongate, vertically disposed body of flexible material having a fluid conducting passage extending therethrough and a; radially outwardly and upwardly projecting flange, adapted to cooperatively engage the seat in the float collar and adapted to be urged past the shoulder in the collar to establish locked engagement therebelow and an upwardly projecting cylindrical boss on the casing string wiping plug having an annular, outwardly opening channel about its periphery, a central, upwardly opening socket with an annular radially opening recess and carrying an expansible snap ring, said boss on the casing string wiping plug being normally engaged in the lower end of the adapter and engaged by said releasable plug engaging means and a drill pipe wiping plug having an elongate cylindrical head, and an elongate, vertically disposed body of flexible material projecting upwardly from the head, the head having a radially, outwardly projecting flange, the body having radially outwardly projecting parts adapted to establish sealed wiping engagement in the drill string, said drill string wiping plug being insertable into the drill string at the top of the well and to be urged downwardly therein by fluid pressure to engage the easing string wiping plug so that the head thereof enters the socket in the casing string wiping plug to shut ofl flow therethrough and so that the flange on the head is urged past the snap ring in the socket to establish locked engagement therein.

4. A well cementing apparatus of the character referred to adapted to be related to a set casing in a well bore including, an elongate, fluid conducting drill pipe string depending into the fixed casing from the top of the well, a setting tool with a central, longitudinally shiftable, fluid conducting kelly fixed to the lower end of the dnill string, a casing hanger releasably carried by the setting tool and adapted to be actuated into gripping engagement in the set casing by the setting tool, an elongate casing string fixed to the casing hanger and depending into the well bore below the set casing, a float collar engaged in said casing string and including an elongate, vertically disposed, tubular body with an annular, downwardly facing shoulder in its upper end portion, an annular core of easy to drill material in the body and having an annular, radially outwardly and upwardly inclined seat opposing said shoulder and a check valve mechanism in the core to check upward flow of fluid therethrough, an elongate, vertically disposed fluid conducting cementing tool connected to the lower end of the setting tool kelly to establish open communication therewith and carrying packers to slidably engage and seal in the easing string, an elongate, vertically disposed, tubular fluid conducting adapter engaged with and depending from the cementing tool and having a radially inwardly projecting shear pin in the lower end portion, a casing string wiping plug including an elongate, vertically disposed body of flexible material having a tubular fluid conducting core and a plurality of vertically spaced, radially outwardly projecting flanges, the lowermost flange being upwardly inclined to coorepatively engage the seat in the float collar and adapted to be urged past the shoulder in the collar to establish locked engagement therebelow and an upwardly projecting cylindrical boss on the casing string wiping plug having an annular, outwardly opening channel about its periphery, a central, upwardly opening socket with an annular radially opening recess and carrying an expansible snap ring, said boss on the casing string wiping plug being normally engaged in the lower end of the adapter with the shear pin engaged in the channel therein and a drill pipe wiping plug having an elongate cylindrical head, and an elongate, vertically disposed body of flexible material projecting upwardly from the head, the head having a radially, outwardly projecting flange and a radially outwardly opening channel and carrying a sealing ring, the body having a plurality of vertically spaced, radially outwardly projecting flanges adapted to establish sealed wiping engagement in the drill string, said drill string wiping plug being insertable into the drill string at the top of the well and to be urged downwardly therein by fluid pressure to engage the casing string wiping plug so that the head thereof enters the socket in the casing string wiping plug to shut 01f flow therethrough and so that the flange on the head is urged past the snap ring in the socket to establish locked engagement therein.

5. A well cementing apparatus of the character referred to adapted to be related to a set casing in a well bore including, an elongate fluid conducting drill pipe string depending into the fixed casing from the top of the well, a setting tool with a central, longitudinally shiftable, fluid conducting kelly fixed to the lower end of the drill string, a casing hanger releasably carried by the setting tool and adapted to be actuated into gripping engagement in the set casing by the setting tool, an elongate casing string fixed to the casing hanger and depending into the well bore below the set casing, a float collar engaged in said casing string intermediate its ends and including an elongate, vertically disposed, tubular body with an annular inwardly opening channel in the upper end and a snap ring engaged in the channel to pro ject therefrom and establishing a downwardly facing shoulder portion, an annular core of easy to drill material in the body and having an annular, radially outwardlyand upwardly inclined sea-t opposing said shoulder and a check valve mechanism formed of easy to drill material in the core to check upward flow of fluid therethrough, an elongate, tubular pup joint fixed to and de' pending from the setting tool kelly, an elongate, vertically disposed fluid conducting cementing tool connected to the lower end of the pup joint to establish open communication therewith and carrying in plurality of vertically spaced cup-shaped packers to slidably engage and seal in the casing string, an elongate, vertically disposed, tubular fluid conducting adapter engaged with and depending from the cementing tool and having a downwardly opening socket in its lower end and carrying a radially inwardly projecting shear pin, a casing string wiping plug including an elongate, vertically disposed rubber body having a tubular fluid conducting core of easy to drill material and a plurality of vertically spaced, radially outwardly projecting flanges, the lowermost flange being upwardly inclined to cooperatively engage the seat in the float collar and adapted to be urged past the shoulder in the collar to establish locked engagement therebelow and an upwardly projecting cylindrical boss on the casing string wiping plug core having an annular, outwardly opening channel about its periphery, a central, upwardly opening socket with an annular radially opening recess therein and carrying an expansible snap ring, said boss on the casing string wiping plug being normally engaged in the lower end of the adapter with the shear pin engaged in the channel therein; and a drill pipe wiping plug having an elongate, cylindrical head of easy to drill material, and an elongate, vertically disposed rubber body projecting upwardly from the head, the head having a radially outwardly projecting flange and a radially outwardly opening channel and carrying a sealing ring, the body having a plurality of vertically spaced, radially outwardly projecting flanges adapted to establish sealed wiping engagement in the drill string, said drill string wiping plug being insertable into the drill string at the top of the well and to be urged downwardly therein by fluid pressure to engage the casing string wiping plug so that the head thereof enters the socket in the casing string wiping plug to shut off flow therethrough and so that the flange on the head is urged past the snap ring in the socket to establish locked engagement therein.

References Cited in the file of this patent UNITED STATES PATENTS 1,842,107 Lytle Jan. 19, 1932 2,164,190 Klomp June 27, 1939 2,228,503 Boyd et a1. Jan. 14, 1941 2,315,931 Burt et al. Apr. 6, 1943 2,481,422 Hayness et a1 Sept. 6, 1949 2,546,978 Collins et al. Apr. 3, 1951 2,621,742 Brown Dec. 16, 1952

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