|Publication number||US2717645 A|
|Publication date||Sep 13, 1955|
|Filing date||Mar 13, 1950|
|Priority date||Mar 13, 1950|
|Publication number||US 2717645 A, US 2717645A, US-A-2717645, US2717645 A, US2717645A|
|Inventors||Schnitter Sylvester B|
|Original Assignee||Schnitter Sylvester B|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (10), Referenced by (10), Classifications (6)|
|External Links: USPTO, USPTO Assignment, Espacenet|
Sept. 13, 1955 s. B. SCHNITTER 2,717,645
SPACING AND DIVERSION OF FLOW OF FLUIDS IN WELL CONDUITS Filed March 15,' 1950 I5 Sheets-Sheet 2 Win, flog- Sylvesfer B. Schn/ffer A TTORNE Y Sept. 13, 1955 s. B. SCHNITTER SPACING AND DIVERSION OF FLOW OF FLUIDS IN WELL CONDUITS I5 Sheets-Sheet 5 Filed March 15, 1950 INVENTOR.
A TTORNEY Sylvesfer B. Schn/Her BY Z I Unite States Patent 0 i SPACING AND DIVERSION OF FLOW OF FLUIDS IN WELL CONDUITS Sylvester B. Schnitter, Dallas, Tex.
Application March 13, 1950, Serial No. 149,281
7 Claims. (Cl. 166156-) This application is concerned with the spacing and flow diversion of fluids moved in a vertically disposed conduit; and it is particularly concerned with apparatus to segregate and maintain the uniformity of the fluids moved through a conduit to a well bore during a well cementing operation or the like.
This invention is primarily designed to maintain the uniformity of the various fluids used during a well cementing operation. These fluids ordinarily consist of well mud and cementing slurry. It may, however, be employed to divert, space and segregate fluids in other well operations.
A prime object of my invention is to provide a systern for diverting the flow of fluids in a casing bore, or other pipe string, which does not restrict the volume of flow permitted by the openings through conventional pipe bore fittings employed in well cementing operations and the like.
The invention also provides the means for maintaining the homogeneity of fluids moved through a well conduit, the means comprised of improved tractable spacer plugs which provide for positive segregation and division of fluids in the well conduit.
The requisites of the spacer plug used with my invention are that it be capable of being collapsed to pass through a shut-ofi unit and elongated and reduced in diametrical form to be confined in the plug receptacle, while at the same time it provides effective seal against the bore walls of the conduit through which it is moved; and that it be provided with joinder members to which may be attached the necessary seating and connector elements. The plub described herein, although excellent for the purpose, may take varied forms and still accomplish the purposes of this invention.
The addition of the foregoing, other and further objects are attained by my invention, as follows:
1. The provision of a multi-plug well cementing apparatus wherein the bottom fluid spacer plug is entrapped within a receptacle in the casing without exerting undue pressure thereon to thereby allow fluid to flow therearound, and without restricting the flow of fluid in the casing any more than it is already restricted by conventional cementing fittings disposed in the casing strings.
2. The provision of such a well cementing apparatus in which the bottom fluid spacer plug is so impounded and about which the fluid is flowed therearound, and in which the top plug is stopped in the casing string at a point separated from, and above, the impounded bottom plug.
3. The provision of such a cementing apparatus wherein the bottom fluid spacer plug is stopped at such a position in the casing string without impacting it upon a casing fitting and thereby eliminating the danger of rupturing, disintegrating or distorting the plug.
4. The provision of apparatus for segregating and diverting the flow of diflerent fluids passed through a tubular conduit within a well bore, wherein a multiplicity of spacer plugs may be entrapped and impounded within EJ111545 Patented Sept. 13, 1955 a receptacle in the tubular conduit to allow fluids to pass thereabout, and wherein the top fluid spacer plug is stopped and stalled at a point above and separated from the receptacle for the preceding plug or plugs.
5. The provision of a fluid diverting plug receptacle to be used in such a cementing method, which receptacle may be slideably positioned at a selected place within a pipe string.
6. The provision of such a plug receptacle having a central passage therethrough, which passage may be closed to thereby stop and entrap a plug or plugs passed thereinto.
7. The provision of such a plug receptacle having a central passageway therethrough and a passageway thereabout, either of which passageways permits a volume of flow through the pipe in which it is positioned not less than the volume of flow permitted through the pipe by the conventional fittings provided in the pipe string.
8. The provision of such a plug receptacle having a central opening therethrough which is of sufficient diameter to permit the passage of a tripping ball or other element provided as an auxiliary unit with which to hydraulically operate apparatus in the casing bore below the receptacle.
9. The provision of a shut-oft unit attached to a pipe string above the aforesaid plug receptacle, such unit having a tapered central passage therethrough which is lesser in diameter than the bore of the casing to which it is attached but provides fluid passage therethrough not lesser in volume than'permitted by passages provided through conventional fittings attached to a casing string of which the shut-01f unit is a part.
10. The provision of such a shut-off unit which permits a collapsible tractable spacer plug to pass therethrough, but has a valve seat therein to receive and seat a valve element attached to, and conveyed through the pipe string by, a collapsible spacer plug, to thereby stop the flow of fluids in the pipe -string.
11. The provision of a composite collapsible fluid spacer plug having complementary segments, such segments being joined together at their central cores, whereby in passing a constriction in a pipe bore one segment may be collapsed and flexed while passing through such opening, but the other segment is sealingly engaged to the bore walls of the casing.
12. The provision of such a composite plug having two complementary segments, each of the said segments having a multiplicity of compartments spaced about the opposed ends of the segments, the said compartments communicating with oppositely disposed compartments, and one of the said segments having orifice openings through the end thereof causing communication between each compartment therein and the pipe bore in which the plug is placed.
13. The provision of such a plug having means on the outer ends thereof, whereby it may be connected to other elements conveyed by said plug. in a casing bore or to other plugs.
14. The provision of such joinder means whereby a multiplicity of such composite plugs or segments thereof may be attached in tandem for movement in a casing bore.
15. The provision of a connector element for joining segments of the plug, a multiplicity of such plugs, or elements to be conveyed by such plug, such connector element having a hole therethrough through which a plug bar may be inserted to hold the plugs and elements attached thereto within a cementing head prior to release into the casing string.
16. The provision of a tractable, collapsible spacer plug having a tapered seating element attached to the ICE a lower.side thereof adapted to seat in a complementary seat within a casing string.
17. The provision of a tapered seating element adapted to be attached to, and to be conveyed in a well conduit by, a collapsible plug, such seating element having a plurality of annular recesses thereabout.
Other and further objects of my invention will become apparent upon reading the detailed description thereof hereinafter following.
Preferred embodiments of my invention are shown in the attached drawings in which,
Fig. I is a fragmentary cross-sectional side elevational View of a string of casing showing a well cementing job in progress with cementing'slurry'confined between my top and bottom tractable fluid spacer plugs, and showing my plug receptacle and stall collar in position in the casing;
Fig. II is a fragmentary cross-sectional side elevational view of a string-of casing in position in the well bore after'the cementing job has been completed showing the cementing slurry'between the casing and the walls of the well bore, and showing the bottom tractable fluid spacer plug entrapped within the plug receptacle, and showing the top fluid spacer plug stopped at the stall collar;
Fig. III'is a cross-sectional side elevational view of the plug receptacle used with my invention;
Fig. IV is a side elevational view, partially sectionalized, of the preferred'form of my composite tractable fluid spacer plug used with my invention, having a joinder member connected to the lower end thereof;
Fig. V is a side elevational view, partially sectionalized, of a modified form of my tractable fluid spacer plug, having an extended joinder member between the complementary segments thereof;
Fig. V1 is a side elevational view, partially sectionalized, showing two composite fluid spacer plugs connected together by an extension coupler, andalso showing another modified form of tractable spacer plug;
Fig. VII is a cross-sectional view taken along the line V1'IVII of Fig. IV;
Fig. VIII is a cross-sectional view taken alongthe line- VIII-VIII of Fig. V;
Fig; IX is'a side elevational view, partially'sectionalized, of a typical valve seating unit used with my invention; and
Fig. X is a cross-sectional view taken along the line X-X of Fig. VI.
Numeral references are employed to designate the various parts of my invention shown in the drawings, and like numerals are usedto designate like parts throughout the various figures of the'drawings.
In Fig. I, the numeral 1 designates a'portion'of a casing string after it has been guided and floated into a well bore 2'to the desired level in order to begin a well cementing operation.
A float shoe 3 is threadedly engaged to' the lowermost joint of easing 4 by means of the engagement of the male thread 5.0K the outer side of said casing joint 4 to the female thread 6 on. the inner'side of the float shoe body 7L The float shoe 3 is of conventional type, having aball valve therein responsive to pressure, so that when-pres:
sureis exerted from outside the casing the ball will seat across, and close, the passage 23 through said shoe.
The plug receptacle 8v is slideably positioned in the lowermost joint of casing 4 above the float shoe 3 and contiguous thereto, the lower end thereof resting on. a
shoulder 3a provided by the upper surface of the float shoe;
The shut-01f collar 9 surrounds a body portion 10 made of metal, such as aluminum. The body 10 has a central opening therethrough comprisedof a. tapered entry surface 11, and a smaller tapered seating surface 12. The. entry surface 11 provides a guiding surface for guiding spacer plugs through the body 10 and the seating surface 12 provides a seat for the tapered seating element 17' at tached to the lower side of the top plug 16, the respective surfaces 11 and 12 havingdiiferent inclinations. The smallest diameter of passage through the body 10 is larger in diameter than the seating element 20, attached to the bottom plug 19, and allows such seating element to pass therethrough.
The body 10 is under-cutto provide an annular shoulder 13, and such shoulder rests upon the upper threaded end 14 of the lower joint 4, and the upper end of the body it abuts against the lower threaded end 15 of the next adjacent upper joint of easing. When the two joints of easing are joined by the shut-off collar 9,.the body 10 is thereby secured to the casing string.
As shown in Fig. I, the top spacer plug 16, having a tapered seating element 17 attached below it by means of a joinder member 13, spaces and separates the cementing slurry 2.1 below it from the well mud 22 above it; and the bottom spacer plug 19, having a tapered seating element'20 attached to the lower end thereof, spaces and divides the cementing slurry 21 above it from the well mud below it. The cementing slurry 21 is thus confined betwcen'the top plug 16 and the bottom plug 19, within the casing bore.
The cementing slurry ordinarily employed in a well cementing operation is a denser, heavier and more viscous fluid than the well mud.
By reason of the pressure thus exerted by the heavier slurry, and by reason of' the pressure from the pumps, a pattern of internal fiow, indicated by the numeral 24, is shaped to conform to contours of restrictions within the casing, such as the central opening through the shut-ofl body 10 and the passage 23 through the float shoe 3. This phenomenon is occasioned by the fact that when fluid is moved through a conduit there is a faster core flow at the interior of the fluidcolumn and a slower movement of flow at the outer perimeter of thefluid column. The restrictions in the casing in a cementing operation accentuate the differential of flows. The flow of fluids at the outer perimeter is indicated by the numeral 25.
Byreason of such diverse flow streams within a casing bore during a cementing operation, spacer plugs employed to separatefluids within the casing bore are subjected to their divergent forces.v The drive force ofthe perimeter flow of heavier slurry exerts a greater pressure circumferentially above the bottom spacer plug than the resisting force of the perimeter flow of the lighter well mud below the bottom spacer plug; and conversely, the force of'the perimeter flow of lighter well mud exerts a lesser drive pressure circumferentially above a top spacer plug than the resisting pressure of the perimeter flow of the denser slurry below the top spacer plug.
These divergent flows within'a well casing have in the past caused the easily yielding wipers or seals on previouslyused spacer plugs to'flex and permit the by-pass of slurry thereabout to thereby cause leakage into the well mud.
The. spacer plug-employed with my invention is designed. to effectively control such forces encountered within the-casing. bore duringa cementing operation, and to provideeffective and positive seal against the bore walls of the. casing, tothereby; segregate and divide the various fluids employed.
The preferred form of my spacer plug is shown in de- V tail inpFig. IV. It is made of rubber or other resilient material capable of being stretched, deformed and reducedin-diametricalform-and to recover to its original form after stretching anddeformation.
It is a composite plugmade of complementary segments 26 and 27. The upper segment 26-h-asa d0wnwardly and inwardly receding baffle 28, which forms a coucaved cupalike area 29 on its upper face; and such segment. has. aplurality of rib-like partitions 3t) spaced peripherally about its lower face and. extend outwardly from the core 37 to the inner surface 35 'of the sealing rat C faces 32 and 33, to thereby form a series of compartments 31 about the lower face thereof.
The sealing faces 32 and 33, on the outer periphery of the segment 26, diverge outwardly from the point of their smallest diameters.
The upper end of the plug is beveled to converge inwardly and form an inwardly converging trailing edge 34.
Each compartment 31 is defined by the inner surface 35 of the sealing faces 32 and 33, the lower surface 36 of the bafile 28, the outer surface of the plug core 37 and two partitions 30.
The core 37 of the upper segment 26 is made up of an outer layer of rubber, an interior tubular metallic core 38, and a rubber core 39 within the tubular core 38. The central tubular core 38 is filled with the rubber 39 through the hole 40 at the time of moulding the plug segment 26.
An externally threaded upper extension 41 on the tubular core 38 extends above the outer rubber layer of core 37 and protrudes into the concaved space 29 on the upper end of the segment for the purpose of receiving a connector or joinder to provide attachment of a seating element or another segment.
An externally threaded lower extension 42 of the tubular core 38 is provided with a clearance 43 within the outer rubber layer of core 37 for the purpose of threadedly receiving the sleeve coupling 44. The sleeve coupling 44 is also secured to the threaded upper extension 59 of the tubular core 55 of the bottom segment 27, to thereby join the two segments 26 and 27 of the composite plug together.
The lower segment 27 has an inwardly receding baffie 45 across the lower face thereof, which forms a concaved area 46 on the lower side of such segment.
The upper side of the segment 27 has a series of peripherally spaced rib-like partitions 47 disposed thereabout, which join the core 54, the upper surface of the baffie 45, and the inner side 52 of the sealing faces 49 and 50. Such partitions form compartments 48 about the upper face of the segment 27, and the compartments 48 are oppositely disposed to the compartments 31, on the lower side of the upper segment 26. Such compartmented areas intercommunicate when the composite plug is disposed within a tubular casing wherein the outer sealing faces of the respective segments are engaged to the inner walls of the casing. The casing bore provides closure of the space between the respective sealing faces of the oppositely disposed segments.
The sealing faces 49 and 50 and 32 and 33 on the outer periphery of the respective segments of the composite plug relaxed position but are brought into a straight plane against the bore wall of the casing when the plug is pressured into the casing and elongated.
The lower end of the segment 27 is bevelled to form an inwardly converging trailing edge 51.
Each of the compartments 48 is defined by the inner surface 52 of the sealing faces 49 and 50, the upper surface 53 of the baffle 45, the plug core 54 and two partitions 47.
The segment 27 has a core 54 made up of an outer layer of rubber, an inner metallic tubular core 55, filled with rubber 56, such rubber 56 being injected into the core through the hole 57 at the time the segment is molded.
The tubular core 55 has an outwardly threaded extension 58 on the lower end thereof and an upper threaded extension 59 on the upper end thereof. The threaded extension 58 extends beyond the outer rubber layer of core 54 into the concaved area 46 and threadedly receives the joinder member 18 by means of the female threads 70 thereon being screwed upon the threaded extension 58. The upper extension 59 is screwed into the sleeve 44. to thereby join the two segments together in the manner hereinbefore recited. A clearance 60 is provided in the outer rubber layer of core 54 to receive the sleeve 44.
are outwardly diverging while the plug is in p all) An orifice-like opening 61 is provided through the baffle 45.into each of the compartments 48 for the purpose of allowing fluid to escape from the compartments when the plug is deformed and for allowing fluid to re-enter the compartments when the plug is reformed.
The top plug 16 and the bottom plug 19 are exactly the same in construction and operation.
Each of the spacer plugs 16 and 19 has a seating valve member attached to the lower end thereof.
These seating elements, designated in Figs. I and II as 17 for the top plug and 20 for the bottom plug, are exactly the same in construction, the difference being only in the outside diameters thereof. The diameter of the seating element 20 must be small enough to pass through the central opening in the shut-off body 10, but is adapted to be seated in the taper 92 within the plug receptacle 8. On the other hand the seating element 17 is larger in diameter than the seating element 20 and is adaptedto be seated and stopped within the tapered seating surface 12 in the body 10.
A typical seating element, designated as 62, is shown in Fig. IX. It is preferably made of metal such as aluminum, which is capable of being drilled up by a drill bit. It is cylindrical and has tapered sides 64 and a bevelled lower end 65 for the purpose of guiding the seating element into its complementary seat. It has a bevelled upper end 66, and a plurality of annular grooves 67 about the periphery thereof. The grooves 67 are provided for the purpose of receiving articles of irregular formation such as granular chips of rock and the like therein, when the element 62 is seating in its tapered seat, to thus allow it to more readily conform to the seat.
An internally threaded bore 68 is provided centrally in the top of the seating element. The threaded bore 68 is provided to receive the externally threaded extension 71 on the connector member 18 or the externally threaded end 74 of a connector like that shown at 73.
The seating element 62 may be connected to the spacer plug by means of the joinder element 18 or by means of a joinder element like the one designated as 73 in Fig. V.
The joinder member 18 is especially adapted for use with the top plug, in that it has a hole 72 therethrough for the purpose of receiving a hanger bar inserted through the cementing head to thus suspend the top plug in the cementing head until it is desired to withdraw the hanger bar from hole 72 and release the top plug into the casing string.
The connector 73, which is cylindrical and has a threaded lower extension 74 and an upper threaded extension 75, may be used for joining the seating element to a spacer plug where it is not desired that the plug be suspended within the head. Such joinder member is connected to the plug by means of a sleeve coupling member like that shown at 76.
The plug receptacle 8 is shown in detail in Fig. Ill. It is preferably made of drillable metal, such as aluminum, and has a tubular body portion 78, with a cylindrical head portion 79 thereon. The head 79 is undercut to form a shoulder 80 and an extension 81. The upper larger diameter 82 of the head v79 is substantially the same diameter as the interior of the casing string in which it is inserted, and is adapted to slide thereinto.
The extension 81 is undercut to form a shoulder 83 and an extension 84; and the head 79 is joined to the body portion 78 by sliding the extension 84 into the body portion 78 until the upper end of such body portion abuts against the shoulder 83. The rivets 85 pass through the body portion 78 and the extension 84 to secure the head 79 and body portion 78 together.
The upper larger diameter 82 of the head 79 is divided rality of peripherally spaced apertures or passageways 87 through which fluid may pass and flow around the plug 7 receptacle when the central passage therethrough is closed.
The plug receptacle base 88 is in-cut to form the shoulder 89' and the upper extension 90. The'extension 90 is inserted within the cylindrical body 78 so that the lower end thereof rests on the shoulder 89, and such extension is secured to the lower end of body 78 by means of the rivets 91 passing therethrough.
The receptacle base 88 is bored to provide a continuous seating bore 92 therein to receive and seat the seating element 20, attached to the bottom plug 19.
The receptacle base 88 has a lower enlarged cylindrical diameter 93, which slideably fits the interior bore of the casing string. Such enlarged. diameter is cut and formed into a. plurality of peripherally spaced, inwardly tapered, fingers 94 provided with apertures or passageways 95 therebetween so that fluid may flow about the plug receptacle and through such apertures when the plug receptacle is positioned in the casing bore. The lower ends of the fingers 94 are provided with flat surfaces 96, or surfaces of suitable contour, to conform to the upper side of the casing fitting onwhich they rest. Ordinarily they will rest upon the upper side of the float shoe, but they maybe made to rest upon any shoulder or support pro vided within a-tubu-lar conduit.
When using the plug receptacle 8 in a cementing operation it is ordinarily slideably inserted in the first joint of easing asthe casing is made up and run into the Well. It ordinarily rests upon the upper side of the float shoe. However, in the'event the receptacle is being used in a stagecementing operation or in a squeeze or other well operation, a shoulder may be provided within the tubular joint abovethe place where the cement is to be discharged.
The operation and function of my system of well cementing, employing the plug receptacle and the preferred form of spacer plug described above is as follows:
The casing string is made up as it is guided and floated to the proper level in the well bore.
A float shoe is positioned on the lower end of the first joint of easing after the plug receptacle 8 has been slideably placed therein. Usually, at the first joint of casing abovethe. float shoe, the shut-ofi? unit body 10 is secured in the manner hereinbefore described. Then the successive numbers of joints of easing, as required, are progressively added to the casing string as it is floated into the well bore.
After the casing string has reached its proper level in the well bore pumping. circulation is established in the cementing circuit by pumping well mud downwardly through the casing bore, discharging it through the float shoe and returning it upwardly in. the well bore behind the casing string to thesurface storage facilities.
For the purpose of such circulation, a circulating head, having openings thereinto, is attached to the top of the casing string to provide communication between the casing and the pumping line which supplies the well .mud. The well mud is thereby circulated through the well flow circuit.
After completion of the circulation, the circulating head is ordinarily removed from the casing string, and the bottom spacer plug19', with theseating element 20 attached thereto, is inserted into'the casing.
Before the plug is inserted into the casing, it is'good practice to remove a small amount of fluid from the casing joint, approximately in a-volume slightly greater than the displacement area of the plug. inserted therein.
To facilitate the insertion. of'the. plug into the casing joint, a tube of small diameter can be rested against the bore wall of the casing joint and allowed to extend above The plug is top of the casing string. Such cementing head is provided with valved connections which may be connected to the surface pumps. The top spacer plug is releasably mounted within thecementing head before it is emplaced upon the casing string. This is accomplished by inserting a withdrawable bar disposed within the cementing head, through thehole 72, provided in the connector member 18.
Thus, with the bottom spacer plug in position in the topmost casing joint-and the top plug releasably attached within the cementing head, the casing string is in readiness to receive the slurry charge.
By valvev manipulation the slurry is pumped by the surface pump through the cementing head above the bottom spacer plug.
When the required amount of slurry has been pumped into the casing string the cementing pump line is closed andthe plug release bar in the cementing head is pulled outward to free the top plug, so that it may enter the casing string above the slurry charge, and move downward The pump line is then directed.
in the casing bore. through the cementing head to pump well mudbehind the top cementing plug and chase the slurry charge, confined between the top and bottom plugs, downwardly through the casing bore, the well mud being spaced and segregated from the cementing slurry by the top and bottom plugs to prevent contamination and mixing.
When the bottom spacer plug 19 reaches the shut-off body 10, the seating element 20, attached thereto, passes therethrough. The bottom plug 19 being tractable and made of resilient material and having hollow compartments therein, may be made to stretch and reduce itself in diametrical form and collapse through the central opening in body 10. During such process it does not lose sealing contact with the bore walls of the casing by reason of the fact that it is made in complementary segments.
' While the lower segment 27 is being stretched, elongated,
collapsed and constricted to pass through such restricted passage, the upper segment 26 maintains its sealing contact with the walls of the casing bore. In fact such sealing is increased by reason of the fact that in collapsing and being reduced in diametrical form, the fluid in compartments 48 in the lower segment 27 is caused to thrust into the oppositely disposed compartments 31 in the segment 26. The pressure within the compartments 31 is thereby increased.
When the lower segment 27 is collapsed and constricted part of the fluid therein is discharged through the orifice openings 61, and after the plug passes the restriction it reforms to its original shape and size, and fluid is replaced back into the compartments 48 by suction through the openings 61, and by the discharge from upper segment 26 when it is constricted through the restriction.
After the lower segment 27'passes the central opening in body it), it recovers to its original shape and the outer sealing faces thereof again impinge on the walls of the.
casing. At the same time the upper segment 26 reaches the central opening in body 10 and is stretched, elongated, collapsed and constricted therethrough while the lower segment maintains sealing contact with the walls of the casing. Thus, there is always a positive seal to prevent leakage around the plug while it is passing through a restricted passage in the casing string.
The oppositely disposed compartments 31 and 48 are always filled with fluid while the spacer plug is disposed and moved within a casing string, and provide rigidity to the plug while it is submerged under pressure. However the plug may be collapsed, stretched, and elongated by discharging fluid through the orifice openings 61, and fluid is replenished therein upon reforming. The spacer plug could not be collapsed without the openings.61
except by bursting it.
After the bottom plug passes the central opening in body 1.0 it moves on downward in the casing joint 4 until' itencounters the plug receptacle 8. The seating unit 20 is guided into the body of the plug receptacle 8by the tapered entry fingers 86, and mates with the tapered seating bore 92, thereby closing the central passage through receptacle 8. The bottom plug 19, attached thereto, is guided into the smaller diametrical area of the receptacle and is collapsed and elongated therein to be entrapped and impounded therein in the manner shown in Fig. 11. The cementing slurry, with the top plug 16 thereabove, is then directed through the apertures 87 around the outside of the receptacle body '73 through the lower apertures 95 and through the float shoe 3 to the well bore.
It is pointed out and emphasized that the area between the plug receptacle body 78 and the inner surface of the well casing bore is not less in diametrical area than the restricted passageway through the shoe 3. There is, therefore, no added restriction of flow of fluids through the casing string by closing the central passage through the plug receptacle 8.
It is further pointed out that the central opening through the shut-off body is not less in diametrical area than the area of restricted passageways provided in the float shoe 3.
When substantially all of the cementing slurry has been discharged into the well bore, the top plug 16, with the seating element 17 attached to the lower end thereof, has reached the shut-off body 10. The seating element 17 mates with the tapered seat 12 in the shut-off body 10 and shuts off the flow of fluid throughout the well circuit, thus stalling the surface pumps. The cementing job is then completed. It will be noted that in stopping the seating element 17 in the shut-off body, the plug 16 does not come in contact with the stall unit and is not impacted thereupon, and the sealing effect of the top plug is not affected.
Should it be desired that the pressure be released from the casing string, it can be done and the ball valve within the float shoe 3 will prevent flow-back of fluid into the casing.
My fluid spacer plug effectively confines the forces to which the fluids in the well casing are subjected during a cementing operation, and prevents such forces from causing the intermingling and channeling of the variant fluids.
The outwardly diverging faces on the segments of the composite plug are not parallel to the central axis of the plug when the plug is in relaxed condition, but when the plug is inserted in a casing bore, the greatest outside diameter, being slightly larger than the casing bore diameter, the sealing faces are elongated to become substantially parallel to the central axis of the plug, and will conform to the bore walls of the casing.
Being bilaterally symmetrical, the composite plug will confine the forces thrusted within the well casing from whatever direction they may come.
For instance, if a force of pressure is exerted on the bottom end of the plug, such thrust of pressure is evenly distributed within the lower concaved face of the plug and is transmitted through the baffle face to the interior compartments of the plug through the orifice openings 61; and, if a force of pressure is exerted on the upper end of the plug, such thrust of pressure is evenly distributed within the upper concaved face of the plug and is transmitted through the baflie face to the interior compartments. The partitions provide peripherally spaced webs connecting the baffle, the central core and the inner side of the sealing faces, and support the outer sealing faces to thereby keep them distended against the bore walls of the casing and eliminate leakage thereabout.
An internal force of resistance is present within the plug which maintains the sealing faces on the upper and lower segments in forced sealing engagement with the walls of the casing and cause them to constantly impinge thereon to insure that such forces thrusted against the plug do not cause bypass leakage around the plug. As a consequence the plug sealing faces swab the wall of the casing bore in the direction of thrust.
The composite plug has a solid metal-reinforced central core therein and when in .novemenr in a casing string such core has the attributes of a piston rod supporting a piston. Through the rib partitions it supports the outer sealing faces, prevents the plug from being distorted, and provides rigidity thereto.
The forces exerted upon spacer plugs during a well cementing operation may result firstly, from the differential pressure of the heavier cementing slurry when injected into the well casing as hereinbefore described, and secondly, the force of surface pumps exerted in the well casing to flow the cementing slurry into place behind the well casing after columnar balance has been attained as described above. These forces cause a faster moving internal core flow, conforming to restricted passages, within P the casing and a slower moving perimeter flow within the fluid column.
My tractable fluid spacer plug effectively confines such forces and positively prevents them from causing the bypass of fluids thereabout.
My composite plug may be varied in form and still attain the desired results described above.
In Fig. V is shown a modified form of my spacer plug which has an upper segment 97 and a lower segment 98.
The upper segment 97 has a downwardly and inwardly receding baffle 99 forming an upper wall therefor, and providing a concaved face 100 at the outer end of the segment. A multiplicity of rib-like partitions 101 are provided peripherally about the lower end of the segment 97, and a peripheral partition 102 is provided to extend entirely around the lower end of said segment, such partition 102 extending outwardly from the lower surface 109 of the baffle 99 to the outer end of the partition 101. Thus there is formed a plurality of peripherally spaced outer compartments 103 and a plurality of peripherally spaced inner compartments 104.
Each outer compartment is defined by the inner surface 108 of the sealing faces and 106, the lower side 109 of the bafiie 99, the outer side of the peripheral partition 102 and two of the partitions 101. Each inner compartment 104 is defined by the inner side of the peripheral partition 102, the lower side 109 of bafiie 99, the core 110 and two of the partitions 101.
The outer sealing faces 105 and 106 of the upper segment 97 are outwardly diverging when the plug is in relaxed position, but conform to the bore walls of a tubular conduit when disposed therein. The upper end of the plug is provided with an inwardly converging trailing edge 107.
The upper segment 97 has an internal core 110, having an outer layer of rubber and an internal tubular metallic core 111. The tubular core 111 is filled with rubber 112, such rubber being injected through the hole 113 at the time the plug is molded. A threaded upper extension 114 is provided on the tubular core 111 for the purpose of receiving a joinder element 115; and a threaded portion 116 is provided on the lower end of the tubular element 111 for the purpose of receiving the joinder member 118. i
The joinder member 118 is a modified form of joinder between the two segments of the plug, and it may be substituted for the joinder 44 in the preferred form of the plug shown in Fig. IV. The joinder member 118 has a hole 119 therethrough for the purpose of receiving a plug bar for retaining and suspending the plug within a cementing head. It has an upper internally threaded extension 139 adapted to be joined to the extension 116 of the tubular core 111; and it has a lower internally threaded extension 138 for the purpose of attaching the joinder member to the threaded extension 137 on the upper end of the lower segment 98. i
The lower segment 98 of the modified form of composite plug, shown in Fig. V has an inwardly receding bafl'ie 120 forming a lower face therefor, such baffle having orifice openings 131 and 132 therethrough. Such bafiie 120 forms a concaved area 121 on the lower face of the segment 98. A plurality of spaced ribbed parti- 1-1 tions 122 are provided about the upper end. of the lower segment 98; and peripheral partitions 123 are: provided around. the upper end of such segment. formed a plurality of spaced outer compartments 124 and a plurality of spaced inner compartments 125 aboutthe.
outer side of the core 133, the inn'er-side-of the peripheral.
partition 123, the upper side of the baffie 120, and two of the ribbedpartitions 122.
The upper outer sealing face 126 and the lower'sealing face 127 are outwardly diverging when the plug is in relaxedposition. The inwardly converging trailing edge 128 is provided on the lower end of the lower segment 98 to guide the plug into restricted passages within the easing string.
The orifice openings 131 communicate with, and provide entry into, the outer compartments 124; and the. orifice openings 132 provide entry into the inner compartments 125.
The segment core 133 has an outer layer of rubber and an inner metallic tubular core 134, which is filled-with rubber 135 through the opening 136 at the time the plug is molded.
As hereinbefore mentioned, the threaded extension 137 is provided to join to the joinder member 118 or other joinder members used between the segments of the plug.
The lower extension 140 of the tubular core 134 is provided for the purpose of receiving a joinder member similar to the joinder member 118, or for receiving a joinder 1118111176173, which is attached to the extension 140 by means of the internally threaded sleeve coupling 76.. The joinder member 73 has a threaded extension 74 thereon which may be screwed into a mating bore in the top of a seating member 141, or it-may be used for the purpose of joining it to another plug.
My composite plugs may be connected in tandem, and some well cementing practices may require such joinder.
Fig. VI shows two composite plugs joined together.
The upper plug 142 is connected to the lower plug 143 by means of a joinder member 144, which joinder member is the same in construction as the joinder member 118 hereinbefore described. The joinder member 144 has a hole 145 therethrough for the purpose of receiving a suspension bar withina cementing head. Other types of joindermembers may also be used for such purpose, such as joinder member 73.
Also shown in Fig. Viis another modified form of composite segmented fluid spacer plug. Since the upper plug142 is exactly the same in construction as the lower plug143, a detailed description of the upper plug 142 will sufiice fora description of both.
The modifiedplug has an'upper segment 146 and a lower segment 147. The upper segment 146 has an inwardly receding bafile 14$, forming an upper face therefor, and providing a concaved space 149 on the upper face. The ribbed partitions 154} are peripherally spaced about the lower face of the segment 146, but they do not extend to the interior core 162, as was the casein the other forms of plug disclosed herein. The ribbed partitions 156 form recesses 151a spacedabout the central compartment 151 on the lower face of such segment.
The outer sealing faces 152 and 153 are the same in construction as the outer sealing. faces on the other forms of spacer plug described herein, in that they are outwardly diverging when the plug is in relaxed position but conform to bore walls of a conduit in whichthe plug is disposed. An inwardly converging trailing edge 154 is provi-ded on the upper end of segment 146.
The central compartment 151 is defined'bythe inner.
Thus there is Cir surface 155 of the outer sealing faces the lower surface 156 of the battle 148 and the plug core 157.
The plug core 15-7 has an outer layer of rubber and aninner tubular metallic core 158, such core 158 being filled with rubber 159 in the same manner that the metallic cores in the other forms of plug described are filled. The tubular core 158 is provided with a threaded upper extension 160 thereon for the purpose of receiving joinder members hereinbefore described, and it also has a lower threaded extension 161 which is provided with a clearance 162 thereabout so that the internally threaded sleeve coupling 163 may be screwed thereon for the purpose of joining the upper and lower segments.
The lower segment 147 has an inwardly receding baffie 164 on the lower end thereof which provides-a concaved lower face 165. Ribbed partitions 166 are peripherally spaced about the upper end of the lower segment 147, which ribbed partitions form recesses 167a spaced peripherally about the central compartment 167 on the.
upper face of the lower segment. The outer sealing faces 168 and 169 are outwardly diverging when the plug is in reiaxed position. The lower end of the segment 147 is terminated by an inwardly converging trailing edge 170.
Central cornpartment 167 is defined by the inner surface 171 of the outer sealing faces 168 and 169, the upper surface 172 of the baifie 164, and. plug core173.
The lower se ment 147 likewise has a core'173 therea a I 1n, whlch core has an outer layer of rubber and an inner metallic tubular core 174 filled with rubber 175. A threaded upper extension 176 ofthe tubular core 174 is screwed into the sleeve coupling member 163 to thereby join the segments 146 and 1.47; and the threaded lower extension 177 on the tubular core 174 is screwed into the:
internally threaded extension- 178 on the joinder member 144, thereby joining the two composite plugs 142 and 143. A plurality of spacer plugs of either form disclosed herein, may be joined together in the same manner.
Orifice openings 1.79 are provided through the baffie 164 for the purpose of allowing the interior of the plug" my plugs are joined in tandem all segments of the plugs must have perforated end bafdes except one segment. The segment with the closed end bafiie may be many position on the length of the tandem plug so long as the compartments therein are oppositely disposed to the cornpartments of another segment.
The modified forms of plugs hereinbefore described have the same function and operation as the preferredform of plug described above.
A plurality of spacer plugs may be pocketed within the plug receptacle 8, should it be desired to space a plurality of fluids used in a well cementing or like operation.-
It is to be understood that other and further modifications and forms of my invention, and elements-thereof, may be made without departing from the spirit and scope of the appendedclaims.
1. A flow diverting plug receptacle adapted to be disposed in a well conduit comprising, a head portion adapted to slideably fit in a well conduit; a base portion adapted to slideably fit in a well conduit; an intermediate portion arranged between the head and the base portions,
being of lesser outside diameter than the conduit bore diameter; a tapered central passage throughsaid receptacle; a. plurality of apertures through the head portion communicating with the areaoutside of the intermediate portion; and a plurality of apertures through the base portion communicating with the area outside of the in-.
2. A fluid diverting plug receptacle adapted to be slideably disposed within a well conduit comprising, a tubular body portion of lesser outside diameter than the casing bore diameter in which it is disposed; a head portion adapted to slideably fit the casing bore in which it is disposed, having a passage therethrough communicating with the tubular body portion; a plurality of inwardly tapered entry fingers arranged about the upper end of said head portion; a plurality of spaced apertures provided between the entry fingers communicating with the area behind the said body portion; a base portion adapted to slideably fit the casing bore in which it is disposed; a plurality of inwardly tapered fingers arranged about the outer end of said base portion; and a plurality of apertures arranged between said base fingers communicating with the area behind the said tubular body portion.
3. In a fluid segregating plug, a plurality of separately collapsible segments joined together, each segment having a separate outer sealing face conformable to the bore walls of a well conduit, the opposed ends of the segments having a plurality of compartments arranged thereabout and adapted to intercommunicate when the plug is disposed within a tubular conduit; a concaved face arranged across the outer end of each segment, one of said concaved faces having openings therethrough providing communication between the inner compartments of the plug and the bore of the conduit in which it is disposed.
4. A collapsible fiuid segregating plug comprising, a plurality of separately collapsible segments joined together at their central cores; an outer wall on each segment conformable to the inner walls of the conduit in which the plug is inserted; a concaved end baffle on each segment; a central core disposed in each segment; a plurality of supporting partitions arranged between the core, the outer walls and the end bafile in each segment; a peripherally arranged partition extending around the opposed end faces of the segments; a series of outer compartments spaced about the opposed ends of the segments; a plurality of inner compartments arranged about the opposed ends of the segments; a plurality of openings through the end baffle in one of the segments providing communication between each compartment in said segment and the casing bore.
5. As an article of manufacture, a well cementing plug comprised of two members, each such member being of resilient character and removably joined together by a non-resilient coupling extending therebetween, each such member being provided with a plurality of radially extending webs having their outermost extremities connected by a substantially cylindrical wall extending therearound, a transversely arranged cup-like baffie connected to said webs and said walls to provide closure of the interstices between said webs at one end thereof, the interstices being open at the opposite ends of said webs, the open ends of the interstices facing one another, and one of said baffies having ports therethrough.
6. A combination collapsible plug and valve seating body comprising, a collapsible spacer plug adapted to be disposed within a well conduit; a valve body having a tapered outer face and a series of annular grooves thereabout; and a joinder member, joining the plug and the said valve body.
7. In a fluid segregating plug, for the segregation of fluids in a conduit, two collapsible members joined together, each member having an outer sealing face, and each member having a compartmented end face facing an oppositely disposed compartmented end face on the other member, and each such member having an outer concave end, the outer end on one member being perforated to provide communication between the inner compartments and the bore of a conduit in which the spacer plug may be disposed.
References Cited in the file of this patent UNITED STATES PATENTS 1,857,301 Hardcastle May 10, 1932 1,994,072 Hardcastle Mar. 12, 1935 2,071,390 Crowell Feb. 23, 1937 2,169,356 Dyer Aug. 15, 1939 2,179,812 Calkins Nov. 14, 1939 2,352,744 Stoddard July 4, 1944 2,438,992 Childers Apr. 6, 1948 2,481,422 Haynes et al. Sept. 6, 1949 2,560,692 Hall July 17, 1951 2,591,603 Ragan Apr. 1, 1952
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|US6082451 *||Dec 17, 1997||Jul 4, 2000||Weatherford/Lamb, Inc.||Wellbore shoe joints and cementing systems|
|US6561270||Sep 10, 1999||May 13, 2003||Weatherford/Lamb, Inc.||Plug and plug set for use in wellbore|
|WO1999031349A1 *||Dec 17, 1998||Jun 24, 1999||Lucas Brian Ronald||Method and apparatus for cementing casing in a wellbore|
|WO2000015944A2 *||Sep 10, 1999||Mar 23, 2000||Budde Peter||Plug and plug set for use in wellbore|
|U.S. Classification||166/156, 166/202|
|International Classification||E21B33/16, E21B33/13|