US3926253A

US3926253A - Well conduit cementing adapter tool

Info

Publication number: US3926253A
Application number: US473487A
Authority: US
Inventors: John A Duke
Original assignee: Individual
Current assignee: Individual
Priority date: 1974-05-28
Filing date: 1974-05-28
Publication date: 1975-12-16
Anticipated expiration: 1992-12-16

Abstract

A cementing adapter housing for use in cementing well conduits in a well by connecting with the drilling kelly to maintain desired fluid circulation in the well through a flow passage while providing a flow connection for introduction of the fluid cement into the bore of the well conduit to be cemented. A plug means releasably secured in the housing is actuated for release when desired to prevent contamination of the fluid cement by circulating fluid when moving the cement into position for hardening. The housing is formed in two sections releasably secured together in a manner to enable rapid disassembly at the completion of the cementing operation.

Description

United States Patent Duke 1 Dec. 16, 1975 WELL CONDUIT CEMENTING ADAPTER Primary ExaminerErnest R. Purser TOOL Attorney, Agent, or Firm-Pravel & Wilson [76] Inventor: John A. Duke, 1311 Beaumont St.,

Apt. 44, Baytown, Tex. 77520 [57] ABSTRACT Filedl y 28, 1974 A cementing adapter housing for use in cementing [21] APPL N03 473 487 well conduits in a well by connecting with the drilling kelly to maintain desired fluid circulation in the well through a flow passage while providing a flow connecl l 155 tion for introduction of the fluid cement into the bore [51] Int. Cl: E21B 33/05 f th w ll conduit to be cemented. A plug means re- [58] Field of Search 166/70, 88 l bl r d in the housing is actuated for release when desired to prevent contamination of the fluid cel References Cited ment by circulating fluid when moving the cement UNITED STATES PATENTS into position for hardening. The housing is formed in 2,713,909 7/1955 Baker 166/70 two Seciions releasably Secured together in a manner 3,322,197 5/1967 Baker et al. 166/70 enable rapid disassembly at the Completion of the 3,444,928 5/1969 Pitts 166/70 n ing operation. 3,828,852 8/1974 Delano 166/70 17 Claims, 2 Drawing Figures 1 l J ,L

J5 fit ll" 32 I I! 22.6. i

4 40 40a 3 a, 35a, 39 :5 10.6 42a 38a 41 d- 426 WELL CONDUIT CEMENTING ADAPTER TOOL BACKGROUND OF THE INVENTION This invention relates to the field of a well conduit adapter for use during well cementing operations.

The use of plug containers during well cementing operations is old and well known. For an example of a description and illustration of the prior art and for the details of known well cementing apparatus and procedures, specific reference is hereby made to pages 2293 and 3303 of the Catalogue of Oil Field Equipment and Services, 29th Edition, 1970-71, published by World Oil, Houston, Tex.

Previously, the prior art plug containers were connected to the drilling fluid circulating pumps by disconnecting the flexible line at the rotary swivel and connecting with the plug container. Such a procedure was time consuming and there was a substantial risk that the casing would become stuck in the well bore during this period. In addition, the prior art plug containers were not designed with sufficient strength to support the casing in the well during the cementing operation.

SUMMARY OF THE INVENTION This invention relates to I a new and improved well conduit cementing adapter tool. A well cementing adapter tool having a housing-for connection with the well conduit to be cemented and the drilling kelly. The housing forms a flow passage for enabling circulation through the well conduit and a flow connection for the introduction of fluid cement while supporting the well conduit in the bore hole. A new and improved plug body releasably secured in the flow passage is actuatable for movement from the housing to prevent the fluid cement from contamination by circulating fluids. The housing is formed in two sections releasably secured together in a manner to enable rapid disassembly at completion of the cementing operation. An object of the present invention is to provide a new and improved welll conduit cementing adapter tool.

'A further object of the present invention is to provide a new and improved well conduit cementing adapter tool that may be rapidly disassembled at completion of the cementing operation.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view, in section, of the cementing adapter tool of the present invention operably installed between the drilling kelly and the well conduit to be cemented; and

FIG. 2 is an exploded side view illustrating the separated housing sections and the plug means of the cementing adapter tool.

DESCRIPTION OF THE PREFERRED EMBODIMENT The well conductor cementing adapter tool of the present invention, generally designated A in the Figs. is used for cementing well conduits or casing C in a well.

In a typical well cementing operation, as is well known in the art, the casing C is lowered into the well bore hole (not illustrated) to the desired location for cementing in the annular area between the well casing C and the well of the bore hole to seal and support the casing C in the well. To prevent the casing C from becoming stuck by engaging of the walls of the bore hole during lowering, it is common practice to circulate drilling fluids down the bore B of the casing C and out of the casing C into the annular area between the casing C in the walls of the bore hole for flowing back to the surface (not illustrated). When the casing C is located at the desired location in the well, a first or bottom plug (not illustrated) may be inserted into the bore B of the casing C. Often this was done by prior art plug containers which were mounted at the top of the casing C to be cemented and which provided a connection for the flexible hose that normally ran to the drilling swivel (not illustrated) of the drilling rig (not illustrated) for circulating the drilling fluids. The prior art plug containers provided connections for the introduction of the fluid cement into the bore B of the casing C for circulation down the bore B of the casing C and into the well annulus where the cement was allowed to harden or set for holding thewell casing C in position. The casing C may be either a surface casing, a production casing or may constitute any well conduit desired to be cemented in the well.

As illustrated in FIG. 1, the adapter tool A includes a housing 10 having suitable means, such as threaded pin connection 12, mounted at the lower end of the housing 10 for connecting the housing 10 with the upper end of the well casing C to be cemented. At the upper end of the housing 10, suitable means, such as box threads 14, are provided for connecting the housing 10 with a drilling kelly K in the well known manner. The housing 10 is formed of sufficient strength to support the well casing C at the desired location in the well for cementing.

The substantially tubular adapter housing 10 preferably forms a concentric passageway 16 therethrough for communicating the bore or flow passage F of the kelly with the bore B of the well conduit C for circulating drilling fluids and the like from the drilling swivel (not illustrated) and kelly flow-passageway F through the flow passageway 16 of the housing 10 and the bore B of the well casing C in the well known manner.

As best illustrated in FIG. 2, the housing 10 includes an upper housing section 20 releasably secured to a lower housing section 22 by suitable means, such as the illustrated threaded engagement. Left-handed box threads 23 on the lower end of the upper section 20 engage left-handed box threads 24 (FIG. 1) on the upper end of the lower section 22. While right-handed thread engagement may be utilized, left-hand engagement is preferred for the

threads

23 and 24 in order that the kelly power spinner S (FIG. 1) can be utilized at the completion of the cementing operations to enable a more rapid resumption of drilling operations by the drilling rig as will be set forth in greater detail hereinafter. As the normal right-handed rotation of the kelly K will tend to disengage the

threads

23 and 24, suitable means are provided for preventing inadvertent disengagement of the

threads

23 and 24. The lower housing section 22 forms an exterior surface 22a having a plurality of equally circumferentially spaced lugs 26 formed thereon adjacent the upper annular shoulder 22b of the lower section 22. Movably mounted along the exterior surface 22a of the lower section 22 is a ring member 28 having a corresponding plurality of inwardly projecting lugs or fingers 28a (FIG. 1) which are positioned between the lugs 26 when the ring 28 is in a first or locking position (FIG. 1) to engage the lugs 26 for blocking relative circumferential rotation between the lower housing 22 and the ring 28. The ring 28 is longitudinally movable downwardly to a second or release position (FIG. 2) with the inwardly projecting fingers 28a spaced or released from the lugs 26 for enabling relative circumferential rotation between the lower housing 22 and the ring member 28. Suitable means, such as threaded set screw 29, may be employed to hold the ring 28in the desired position. The ring member 28 is provided with a pair of upwardly projecting extensions 28b and 280 at circumferentially spaced locations thereon.

The upper housing section 20 forms an exterior surface 20a having a pair of protruding portions or members 20b and 20c formed thereon in circumferentially spaced relationship corresponding to that of the upwardly extending

portions

28b and 28c, respectively. When the ring 28 is in the upper or locking position (FIG. 1) the upwardly projecting

extensions

28b and 28c engage the protruding

members

20b and 200, respectively to prevent relative circumferential rotation between the upper section 20 and the ring 28. As the ring 28 is blocked from relative circumferential rotation with respect to the lower housing 22 because of the engagement of the lugs 26 with the projections 26a of the ring 28, relative rotational movement between the upper section 20 and the lower section 22 is thus prevented by right-hand rotation of the housing by the kelly K.

Should the

threads

23 and 24 have sufficient friction therebetween to avoid disengagement when power is applied to the spinner S, additional force to effect separation may be supplied using the ring 28. Normally, the ring 28 will be positioned in order that the upwardly projecting extensions 28b and 280 are positioned in the path of the protruding members b and 200 to block the relative circumferential rotation between the upper section 20 in the lower section 22. By dropping the ring 28 to the lower position and then rotating the ring to move into locking engagement with the lugs 26 on the other side of the protruding members 20b and 20c an additional force from the lower member may be imparted to the upper member to effect release of the

threads

23 and 24. With the locking ring 28 moved back to the upper position but on opposite sides of the protruding

members

20b and 200,

suitable bolts

32 and 33 may be run through threaded

openings

30 and 31, respectively, which are formed through the ring member extensions 28b and 280, respectively for engagement with the protruding

members

20b and 200. By suitable tightening of bolts positioned in the

openings

30 and 31 an additional torque force is imparted to the

extensions

20b and 200 for assisting the spinner S in effecting disengagement of the

threads

23 and 24. Or-

dinarily, the spinner S will have more than sufficient rotational power to disengage the

threads

23 and 24 and it will not ordinarily be necessary to use

bolts

32 and 33 in the

openings

30 and 31 to assist in disengaging

threads

23 and 24. It should be noted also, that bolts in the

openings

30 and 31 may be reversed when the upwardly projecting

extensions

28b and 28c are in the usual rotation blocking position and

bolts

32 and 33 may then be employed in lieu of set screw 29 to hold the locking ring 28 in the upper or locking position. It should also be apparent that the

bolts

32 and 33 in the threaded

openings

30 and 31 may be used in conjunction with the set screw 29 to hold the locking ring in the desired position.

As illustrated in FIG. 1, the housing 10 includes one or more threaded

cement flow connections

34 and 34a which are preferably located with the lower section 22 adjacent threads 24. The

flow connections

34 and 34a are threadedly connected by

conduits

35 and 35a, respectively, having suitable valving (not illustrated) with the source of fluid cement (not illustrated) to be used in cementing the well casing C in the well. While the location of flow connections 34 and 340 with the flow passage -16 of the housing 10 need only be at some intermediate location of the upper and lower ends of the housing 10, the illustrated location is preferred, as the

conduits

35 and 35a provide a lower limit stop support for the ring 28 in the lower or released position.

Located in the flow passage 16 above the cementing

flow connections

34 and 34a may be located a check valve means 36 for blocking flow from the flow passage 16 of the housing 10 into the flow passage F of the kelly K. The illustrated form of the check valve 36 is a pivoted flapper valve that is spring loaded to the upper or closed position for blocking the upwardly flow in the flow passage 16 and which is pivoted downwardly by flow from the kelly K to the position illustrated in phantom for enabling flow from the flow passage F into the flow passage 16 of the housing 10. The valve 36 pivots about an axis provided by attachment pivot pin 36a secured to the housing 10 when moving the valve 36 to and from sealing engagement with the upper portion 20 of the housing 10. Such spring biased closed check valves are old and well known to those of ordinary skill in the art and disclosed in the prior art patents.

Releasably secured in the flow passage 16 below the

cementing connections

34 and 34a is a plug means, generally designated 37, including a plug body 38 having a longitudinal opening of predetermined size formed therethrough for enabling circulation flow of fluid through the flow passage 16 to normally pass the plug body 38. Suitable annular seal means provided by the packing 39 mounted with the plug body 38 for blocking flow of fluid between the plug body 38 and the housing 10 to direct the flow of fluid through the opening 40. The plug body 38 is releasably secured in the housing 10 by suitable means, such as a locking rod 42 which extends from a location adjacent the exterior surface 22a of the lower section 22 through a threaded opening 220 to a recess 22d formed in the flow passageway 16 forming inner wall of the lower housing section 22. The locking rod 42 is provided with threads 42a for engaging the housing threads 220 for securing the locking rod 42 in the locking position. Mounted exteriorly of the housing 10 is a head 42b of the locking rod 42 which is adapted to cooperate with a wrench or the like in the well known manner from exteriorly of the housing 10 for effecting rotation of the locking rod 42 to rotate the rod 42 for threadably engaging or disengaging the threads 22b as desired. Preferably, the rod 42 extends through an opening 38a formed through the plug body 38 for blocking any upward as well as downward movement of the plug body 38. When the rod 42 is withdrawn from the flow passage 16 the plug body 38 is of course released to move from the flow passageway 16 into the bore B of the well casing C.

The flow opening or passage 40 of the plug body 38 is provided with an enlarged upper portion 40a which is necked down at 40b to a lower opening portion 40c. The reducing portion 40b forms an upwardly facing annular sealing surface upon which a plug opening closure member or ball 44 is adapted to seat. When the ball 44,is.seated (illustrated in phantom in FIG. 1) the plug 38 is actuated so that a greater fluid pressure in the flow passage 16 above the plug body 38 will effect a pressure differential across the plug body 38 for moving the plug 38 downwardly as is well known in the art. Both the plug body 38 and the ball 44 are preferably formed of a drillable material to enable resumption drilling operation after completion of the cementing operation as is well known. The upper housing 20 as provided with a threaded opening 46 through which the ball may pass when inserted into the flow passage 16 for actuating the plug body 38 to move in response to the pressure differential. A threaded plug 48 (FIG. 2) is normally employed in the threaded opening 46 to prevent leakage of fluid from the flow passage 16.

OPERATION In the use and operation of the present invention, the well casing C to be cemented is positioned at the desired subsurface location in the well using a drilling rig in a manner well known to those skilled in the art. Circulation of drilling fluid down the bore B of the casing C and up the annulus between the casing in the walls of the well is maintained through the kelly K and the adapter A by breaking the adapter tool A of the present invention from the casing C at pin threads 12 and adding a desired number of joints to the casing C before making up with the top of the added joints using the threads 12. In this manner, the operator will be enabled to maintain drilling fluid circulation with a minimum of delay to prevent the well casing C from becoming stuck in the bore hole.

When the casing C is at the desired location in the well, the source of fluid cement is connected to the

flow connections

34 and 34a while maintaining circulation of the drilling fluid down the bore B of the well casing C. When it is desired to commence the cementing operations, the fluid cement is introduced into the flow passageway through the flow connections 34 while reducing the circulation pressure of the drilling fluid in the flow passage F of the kelly K. The increased fluid pressure in the flow passage 16 will then essentially block any additional flow from the flow passage F of the kelly K into the flow passage 16 and enable the check valve 36 to move to the closed position. Thereafter greater fluid pressure in the flow passage 16 in the flow passage F of the kelly will tend to maintain the check valve 36 in the closed position.

The fluid cement introduced into the flow passage 16 by the

connections

34 and 34a will then flow downwardly through the opening 40 of the plug 38 into the bore B of the well casing C where the fluid cement will circulate downwardly and out the bottom of the well casing C into the annulus. When the predetermined amount of fluid cement to effect the desired well cementing operation has been communicated into the flow passage 16 of the housing 10, the fluid pressure in the flow passage 16 above the plug 38 and atmospheric pressure is equalized by use of the cementing

conduits

35 and 35a valve apparatus. The threaded plug 48 is then removed to enable dropping of the ball 44 through the opening 46 for actuating the plug body and the threaded plug 48 is then replaced.

With the ball present in the flow passage 16 above the plug 38 the

cementing flow connectors

34 and 34a are shut-in using the valves of the conduits and 35a and the drilling fluid circulating pumps are then used to increase the fluid pressure in the passageway F of the kelly K for effecting opening of the check valve 36 and providing sufiicient flow through the opening to seat the ball 44 on the sealing surfaces 40b of the opening 40. Prior to or substantially simultaneous with the commencing to circulate drilling fluid through the flow passage F of the kelly K, the locking rod 42 is removed by effecting rotation thereof from exteriorly of the housing 10. With the ball 44 seated on the sealing surface 40b and the rod 42 withdrawn, the plug 38 will commence to move downwardly in response to the pressure differential across the plug 38. After the plug body 38 has moved down the sufficient distance for clearance, the rod 42 is replaced to prevent inadvertent leakage of fluid through the opening 22c. As is well known, the plug means 36 serve to protect contamination of the fluid cement as it is forced down the bore B of the well casing C by the circulating fluid supplied above the plug body 38 through fluid flow passage F of the kelly K from the circulating pumps. This pressure is also used to move the plug means 36 downwardly in the bore B for forcing the fluid cement into the well annulus for cementing the well casing within the well.

After the cement has set or hardened sufficiently, it is necessary to remove the adapter housing A from the casing C. If the casing C and the adapter housing A are in a position where they may be grabbed by the tongs of the rotary drilling rig, it is preferable that they be used to disconnect the adapter assembly A from the casing C threads 12. The adapter housing A then may be held by the tongs to effect disconnecting of the adapter assembly A from the kelly K at threads 14 to enable resumption of drilling operation.

After the adapter housing A is in the location when the cement has set where it may not be grasped by the tongs for disconnecting from the well casing C. When this occurs, it is only necessary that the set screws 29 be loosened to enable the locking ring 28 to drop to the lower or released position and then operating the kelly spinner S of the kelly K. Operation of the swivel S imparts a right-hand rotation to the kelly K which effects rotation of the upper housing 20 relative to the lower housing 20 for disconnecting at

threads

23 and 24. Should disengagement be particularly difficult, the locking ring 28 may be shifted in the manner previously discussed and secured in the locking position with the lugs 26 for assisting the spinner S in disconnecting the

threads

23 and 24. With the removal of the upper housing 20, rapid resumption of operations for drilling out the concrete plug in the lower end of the placing C may be commenced without the need to break the lower portion of a housing 22 from the casing C at threaded engagement 12.

By predeterrnining the size of the opening 40 through the plug body 38, it will be readily apparent to those skilled in the art that two movable cementing plugs may be employed during cement operations. The only requirement being that the ball (not illustrated) to actuate the lower plug (not illustrated) must be able to pass through the reduced portion 40c of the upper plug 38.

The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the size, shape and materials as well as in the details of the illustrated construction may be made without departing from the spirit of the invention.

I claim:

1. A well conduit adapter for use during cementing of a well conduit in a well, including:

a substantially tubular adapter housing having an upper end and a lower end;

means mounted with said lower end of said adapter housing for connecting said adapter housing with the well conduit to be cemented;

means mounted with said upper end of said adapter housing for connecting said adapter housing with a drilling kelly;

said housing having a flow passage extending therethrough for communicating the flow passage of the drilling kelly with bore of the well conduit; and

plug means releasably disposed in said housing and having a closable opening formed therethrough for enabling circulation through said opening and said flow passage when said plug means is disposed in said housing and operable when actuated to move from said housing to reduce contamination of cement moving through said flow passage from said housing.

2. The structure as set forth in claim 1, wherein:

said housing having a flow connection communicating with said flow passage from externally of said housing intermediate said upper and said lower ends of said housing.

3. The structure as set forth in claim 2, wherein:

said plug means is located in said flow passage between said flow connection and said lower end of said housing.

4. The structure as set forth in claim 2, wherein:

said housing having an upper section, a lower section and means for releasably securing said upper and lower sections to form an integral housing unit capable of supporting the well conduit to be cemented in the well.

5. The structure as set forth in claim 4, wherein:

said means for releasably securing said upper and lower sections including a left-hand threaded engagement wherein relative right-hand rotation of said housing tends to release said upper and lower sections.

6. The structure as set forth in claim 5, wherein said means for releasably securing said upper and lower sections further includes:

a plurality of lugs mounted on an exterior surface of said lower housing;

a ring member movable along said exterior surface to and from a first position engaging said lugs for blocking relative circumferential rotation between said lower housing and said ring members and a second position enabling relative circumferential rotation between said lower housing and said ring member, said ring member having a pair of extensions formed thereon at spaced circumferential locations; and

said upper housing having a pair of protruding members mounted thereon for engaging said pair of extensions formed on said ring member to block relative circumferential rotation between said protruding members and said extension wherein relative right-hand circumferential rotation between said upper and said lower housing when said ring member engages said lugs is blocked.

7. The structure as set forth in claim 2, including:

valve means disposed in said flow passage for blocking flow of fluid in said flow passage from said upper end of said housing while enabling flow of fluid into said flow passage from said upper end of said housing.

8. The structure as set forth in claim 2, wherein said plug means includes:

a plug body having an opening of predetermined size formed therethrough for enabling flow of fluid through the flow passage by said plug body; and

seal means mounted with said plug body for sealing with said housing to direct the flow of fluids through said opening.

9. The structure as set forth in claim 8, including:

means with said housing for releasably securing said plug means with said body housing and operable from exteriorly of said housing to release said plug means for movement through said flow passage.

10. The structure as set forth in claim 8, further including:

said plug body having a sealing surface adjacent said opening; and

a plug opening closure member spaced from said sealing surface for enabling flow of fluid through said opening and movable to seat on said sealing surface for blocking flow of fluid through said opening to effect a desired pressure differential upon said plug means for actuating said plug means to move from the flow passage of said housing.

11. The structure as set forth in claim 1, including:

a plug opening closure means to seal said plug opening as desired so that a greater fluid pressure in said flow passage will effect a pressure differential across said plug for moving said plug downwardly.

12. The structure as set forth in claim 11, wherein:

said plug opening closure means includes a seating surface and a closure member that seats on said seating surface to seal said plug opening to block said circulation through said plug opening.

13. A well conduit adapter for use during cementing of a well conduit in a well, including:

a substantially tubular adapter housing having an upper end and a lower end;

said housing having a flow passage extending therethrough for communicating the flow passage of the drilling kelly with bore of the well conduit;

plug means releasably disposed in said housing for enabling circulation through said flow passage and operable when actuated to move from said housing to reduce contamination of cement moving through said flow passage from said housing;

said housing having a flow connection communicating with said flow passage from externally of said housing intermediate said upper and said lower ends of said housing;

a plug body having an opening of predetermined size formed therethrough for enabling flow of fluid through the flow passage by said plug body;

seal means mounted with said plug body for sealing with said housing to direct the flow of fluids through said opening;

said plug body having a sealing surface adjacent said opening; and

14. A well conduit adapter for use during cementing of a well conduit in a well, including:

a substantially tubular adapter housing having an upper end and a lower end;

said plug means including a plug body having an opening of predetermined size formed therethrough for enabling flow of fluid through the flow passage by said plug body; and

15. A well conduit adapter for use during cementing of a well conduit in a well, including:

a substantially tubular adapter housing having an upper end and a lower end;

said housing having a flow connection communicating with said flow passage from externally of said housing intermediate said upper and said lower ends of said housing; and

16. The structure as set forth in claim 15, wherein:

17. The structure as set forth in claim 16, wherein said means for releasably securing said upper and lower sections further includes:

a plurality of lugs mounted on an exterior surface of said lower housing;

said upper housing having a pair of protruding members mounted thereon for engaging said pair of extensions formed on 'said ring member to block relative circumferential rotation between said protruding members and said extension wherein relative right-hand circumferential rotation between said upper and said lower housing when said ring member engages said lugs is blocked.

Claims

1. A well conduit adapter for use during cementing of a well conduit in a well, including: a substantially tubular adapter housing having an upper end and a lower end; means mounted with said lower end of said adapter housing for connecting said adapter housing with the well conduit to be cemented; means mounted with said upper end of said adapter housing for connecting said adapter housing with a drilling kelly; said housing having a flow passage extending therethrough for communicating the flow passage of the drilling kelly with bore of the well conduit; and plug means releasably disposed in said housing and having a closable opening formed therethrough for enabling circulation through said opening and said flow passage when said plug means is disposed in said housing and operable when actuated to move from said housing to reduce contamination of cement moving through said flow passage from said housing.

2. The structure as set forth in claim 1, wherein: said housing having a flow connection communicating with said flow passage from externally of said housing intermediate said upper and said lower ends of said housing.

3. The structure as set forth in claim 2, wherein: said plug means is located in said flow passage between said flow connection and said lower end of said housing.

4. The structure as set forth in claim 2, wherein: said housing having an upper section, a lower section and means for releasably securing said upper and lower sections to form an integral housing unit capable of supporting the well conduit to be cemented in the well.

5. The structure as set forth in claim 4, wHerein: said means for releasably securing said upper and lower sections including a left-hand threaded engagement wherein relative right-hand rotation of said housing tends to release said upper and lower sections.

6. The structure as set forth in claim 5, wherein said means for releasably securing said upper and lower sections further includes: a plurality of lugs mounted on an exterior surface of said lower housing; a ring member movable along said exterior surface to and from a first position engaging said lugs for blocking relative circumferential rotation between said lower housing and said ring members and a second position enabling relative circumferential rotation between said lower housing and said ring member, said ring member having a pair of extensions formed thereon at spaced circumferential locations; and said upper housing having a pair of protruding members mounted thereon for engaging said pair of extensions formed on said ring member to block relative circumferential rotation between said protruding members and said extension wherein relative right-hand circumferential rotation between said upper and said lower housing when said ring member engages said lugs is blocked.

7. The structure as set forth in claim 2, including: valve means disposed in said flow passage for blocking flow of fluid in said flow passage from said upper end of said housing while enabling flow of fluid into said flow passage from said upper end of said housing.

8. The structure as set forth in claim 2, wherein said plug means includes: a plug body having an opening of predetermined size formed therethrough for enabling flow of fluid through the flow passage by said plug body; and seal means mounted with said plug body for sealing with said housing to direct the flow of fluids through said opening.

9. The structure as set forth in claim 8, including: means with said housing for releasably securing said plug means with said body housing and operable from exteriorly of said housing to release said plug means for movement through said flow passage.

10. The structure as set forth in claim 8, further including: said plug body having a sealing surface adjacent said opening; and a plug opening closure member spaced from said sealing surface for enabling flow of fluid through said opening and movable to seat on said sealing surface for blocking flow of fluid through said opening to effect a desired pressure differential upon said plug means for actuating said plug means to move from the flow passage of said housing.

11. The structure as set forth in claim 1, including: a plug opening closure means to seal said plug opening as desired so that a greater fluid pressure in said flow passage will effect a pressure differential across said plug for moving said plug downwardly.

12. The structure as set forth in claim 11, wherein: said plug opening closure means includes a seating surface and a closure member that seats on said seating surface to seal said plug opening to block said circulation through said plug opening.

13. A well conduit adapter for use during cementing of a well conduit in a well, including: a substantially tubular adapter housing having an upper end and a lower end; means mounted with said lower end of said adapter housing for connecting said adapter housing with the well conduit to be cemented; means mounted with said upper end of said adapter housing for connecting said adapter housing with a drilling kelly; said housing having a flow passage extending therethrough for communicating the flow passage of the drilling kelly with bore of the well conduit; plug means releasably disposed in said housing for enabling circulation through said flow passage and operable when actuated to move from said housing to reduce contamination of cement moving through said flow passage from said housing; said housing having a flow connection communicating with said flow passage from exteRnally of said housing intermediate said upper and said lower ends of said housing; a plug body having an opening of predetermined size formed therethrough for enabling flow of fluid through the flow passage by said plug body; seal means mounted with said plug body for sealing with said housing to direct the flow of fluids through said opening; said plug body having a sealing surface adjacent said opening; and a plug opening closure member spaced from said sealing surface for enabling flow of fluid through said opening and movable to seat on said sealing surface for blocking flow of fluid through said opening to effect a desired pressure differential upon said plug means for actuating said plug means to move from the flow passage of said housing.

14. A well conduit adapter for use during cementing of a well conduit in a well, including: a substantially tubular adapter housing having an upper end and a lower end; means mounted with said lower end of said adapter housing for connecting said adapter housing with the well conduit to be cemented; means mounted with said upper end of said adapter housing for connecting said adapter housing with a drilling kelly; said housing having a flow passage extending therethrough for communicating the flow passage of the drilling kelly with bore of the well conduit; plug means releasably disposed in said housing for enabling circulation through said flow passage and operable when actuated to move from said housing to reduce contamination of cement moving through said flow passage from said housing; said housing having a flow connection communicating with said flow passage from externally of said housing intermediate said upper and said lower ends of said housing; said plug means including a plug body having an opening of predetermined size formed therethrough for enabling flow of fluid through the flow passage by said plug body; and seal means mounted with said plug body for sealing with said housing to direct the flow of fluids through said opening.

15. A well conduit adapter for use during cementing of a well conduit in a well, including: a substantially tubular adapter housing having an upper end and a lower end; means mounted with said lower end of said adapter housing for connecting said adapter housing with the well conduit to be cemented; means mounted with said upper end of said adapter housing for connecting said adapter housing with a drilling kelly; said housing having a flow passage extending therethrough for communicating the flow passage of the drilling kelly with bore of the well conduit; plug means releasably disposed in said housing for enabling circulation through said flow passage and operable when actuated to move from said housing to reduce contamination of cement moving through said flow passage from said housing; said housing having a flow connection communicating with said flow passage from externally of said housing intermediate said upper and said lower ends of said housing; and said housing having an upper section, a lower section and means for releasably securing said upper and lower sections to form an integral housing unit capable of supporting the well conduit to be cemented in the well.

16. The structure as set forth in claim 15, wherein: said means for releasably securing said upper and lower sections including a left-hand threaded engagement wherein relative right-hand rotation of said housing tends to release said upper and lower sections.

17. The structure as set forth in claim 16, wherein said means for releasably securing said upper and lower sections further includes: a plurality of lugs mounted on an exterior surface of said lower housing; a ring member movable along said exterior surface to and from a first position engaging said lugs for blocking relative circumferential rotation between said lower housing and said ring members and a second position enabling relative circumferentiAl rotation between said lower housing and said ring member, said ring member having a pair of extensions formed thereon at spaced circumferential locations; and said upper housing having a pair of protruding members mounted thereon for engaging said pair of extensions formed on said ring member to block relative circumferential rotation between said protruding members and said extension wherein relative right-hand circumferential rotation between said upper and said lower housing when said ring member engages said lugs is blocked.