US20020096334A1

US20020096334A1 - Mudsaver valve

Info

Publication number: US20020096334A1
Application number: US09/766,793
Authority: US
Inventors: Karl LaFleur
Original assignee: Lafleur Petroleum Services Inc
Current assignee: Lafleur Petroleum Services Inc
Priority date: 2001-01-22
Filing date: 2001-01-22
Publication date: 2002-07-25

Abstract

A mudsaver valve for insertion into the upper end of a well casing includes an elongated cylindrical valve body member having a central bore for receiving an elongated generally tubular valve closure member for movement in the body bore between valve closed and open positions. Passages in the closure member open to the outer surface thereof and spaced apart seal members mounted on the closure member prevent fluid flow out of the valve when the closure member is disposed in a closed position in the body. The body supports plural circumferentially spaced spring biased drag blocks or radially deflectable leaf or bow spring members which are engageable with the casing to support the body stationary in the casing so that the closure member may be reciprocated with respect to the body between valve open and closed positions.

Description

FIELD OF THE INVENTION

The present invention pertains to a mudsaver valve for use in well drilling and casing installation operations.

BACKGROUND

In the art of well drilling operations, including operations to install well casing, it is common practice to fill the tubular casing with drill cuttings evacuation fluid, commonly known as drilling fluid or “mud”, and circulate such fluid through the casing and the wellbore during casing installation procedures, in particular. So-called mudsaver valves are usually connected to the lower end of a hollow drill stem drive member or Kelly or to the lower end of a circulating head to prevent spillage of the drilling fluid or “mud” when the Kelly or circulating head are disconnected from the drill stem or casing, as the case may be.

The use of a mudsaver valve is desirable to prevent the aforementioned loss of drilling fluid, to prevent unsafe conditions for rig operating personnel and also to minimize contamination of the environment in the vicinity of the drilling operation.

Various types of mudsaver valves have been developed in the prior art. A typical mudsaver valve design is characterized by a poppet type closure member which is held against a valve seat by a spring. In many instances, solid particulates are distributed throughout the drilling fluid, such as lost circulation material or unseparated drill cuttings, and these particulates become trapped between the valve closure member and the valve seat resulting in improper closure of the mudsaver valve and the loss of drilling fluid out of the circulating head or conduits which supply the fluid during operations.

Another problem associated with prior art mudsaver valves pertains to the inability to at least reliably and substantially equalize the pressure between the casing or drill stem interior passage and the fluid supply conduit to which the mudsaver valve is connected. Fluid pressures in the so-called standpipe or conduit to which the mudsaver valve is connected for supplying fluid to the drill stem or casing should be reduced to substantially the same pressure as the fluid in the drill stem or casing section at the upper end thereof prior to disconnection and withdrawal of the circulating head and mudsaver valve from the casing. However, if fluid pressure should increase in the casing beyond a reasonable value which would permit disconnection of the circulating head from the casing, this pressure can be monitored by suitable instruments connected to the fluid supply conduit or standpipe which is connected to the circulating head. Accordingly, the mudsaver valve should be operable to substantially equalize the fluid pressure in the drill stem or casing with that in the standpipe or fluid supply conduit before disconnecting the fluid circulating head or similar casing installation equipment from the drill stem or casing.

Still another problem associated with prior art mudsaver valves pertains to the rapid deterioration of the valve components due to erosion caused by high fluid velocities between the closure member and the valve seat or through flowports which are provided in the closure member for certain types of mudsaver valve configurations.

Accordingly, the desiderata in mudsaver valves includes (a) reliable operation in moving the valve closure member between open and closed positions to assure that there is negligible spillage of drilling fluid onto the drilling rig floor, (b) assurance that pressures in the casing and the fluid supply conduit are substantially equalized before the fluid supply conduit and mudsaver valve are withdrawn from the well casing and (c) provision of a valve configuration that minimizes erosion and early failure of the valve working parts. It is to these ends that the present invention has been developed.

SUMMARY OF THE INVENTION

The present invention provides an improved mudsaver valve for use in well drilling and casing installation operations.

In accordance with one important aspect of the present invention, a mudsaver valve is provided which includes an elongated tubular mandrel type closure member which is slidably disposed in a generally cylindrical valve body and is movable between valve open and closed positions wherein the mandrel moves relative to the body out of a lower end thereof and substantially clear of any valve seat or seal bore portions of the body which might suffer erosion from high velocity fluid impinging thereon. In accordance with another aspect of the present invention, a sliding mandrel type mudsaver valve is provided which includes spaced apart annular seals which seal off flow of fluid out of the valve when the closure member is retracted into the bore of the valve body.

In accordance with yet another aspect of the invention, a mudsaver valve is provided which includes members mounted on the valve body which frictionally engage the inner borewall of a casing or drill stem section into which the mudsaver valve has been inserted to arrest movement of the valve body and to allow the valve closure member to move relative to the valve body between valve open and closed positions. The sliding mandrel type closure member is movable to a valve open position only after it has been inserted into the upper end of a casing section and the closure member is movable to a valve closed position before the body is forcibly removed from frictional engagement with the inner borewall of the drill stem or casing member. In this way, there is assurance that the mudsaver valve will be in a closed position before it is withdrawn from the upper end of the casing or drill stem section.

In accordance with still a further aspect of the present invention, an improved mudsaver valve is provided which includes an arrangement of resiliently deflectable members which frictionally engage the inner borewall of a casing section to generally hold the valve body stationary but to also allow the valve body to be moved between a working position in the casing and a position retracted out of the casing. Circumferentially spaced spring biased drag blocks or resiliently deflectable leaf or bow type springs may be mounted on the valve body for frictional engagement with the casing borewall to retain the valve body within the casing and to allow for movement of the valve closure member between valve open and closed positions. Elongated flexible finger indicators may be provided on the valve body to visually indicate to operating personnel the position of the valve body in the casing.

Those skilled in the art will further appreciate the above-mentioned features and advantages of the invention together with other important aspects thereof upon reading the detailed description which follows in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevation, in somewhat schematic form, of a casing circulating system including a mudsaver valve in accordance with the present invention; [0013]
FIG. 2 is a longitudinal central section view of the mudsaver valve shown in FIG. 1 partially inserted in the upper end of a well casing section; [0014]
FIG. 3 is a detail section view taken generally from the line [0015] 3-3 of FIG. 2;
FIG. 4 is a longitudinal central section view of the mudsaver valve shown in FIG. 2 fully inserted within the casing section and in the valve open position; [0016]
FIG. 5 is a longitudinal central section view of a first alternate embodiment of the mudsaver valve of the present invention shown within a casing section and in the valve open position; [0017]
FIG. 6 is a top plan view of a removable spring finger drag assembly for the mudsaver valve shown in FIG. 5; [0018]
FIG. 7 is a side elevation of the spring finger drag assembly shown in FIG. 6; [0019]
FIG. 8 is a longitudinal central section view of a second alternate embodiment of a mudsaver valve in accordance with the invention, shown in the valve closed position; [0020]
FIG. 9 is a section view showing the valve of FIG. 8 in an open position; [0021]
FIG. 10 is a side elevation of the drag assembly for the valve shown in FIGS. 8 and 9; and [0022]
FIG. 11 is a bottom plan view of the drag assembly shown in FIG. 10.[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the description which follows, like parts are marked throughout the specification and drawing with the same reference numerals, respectively. The drawing figures are not necessarily to scale and certain features may be shown in somewhat schematic form in the interest of clarity and conciseness. [0024]
Referring to FIG. 1, there is illustrated a portion of a well drilling rig including an arrangement adapted for circulating drilling fluid into and through drill stem or casing sections, in particular, while inserting such casing sections into a wellbore. FIG. 1 shows the upper end of a conventional [0025] well casing section 10 which is adapted to be supported by suitable slips, not shown, prior to insertion of the casing section into a wellbore, also not shown. The circulating assembly includes a rig swivel assembly 12, a lifting bail 14 adapted to be connected to the rig traveling block, not shown, and a conventional casing elevator assembly 16 connected to the swivel 12. An elongated fluid conducting conduit 18 is connected to the swivel 12, depends therefrom and is in communication with a drilling fluid supply conduit 20 connected to the swivel in a conventional manner and to a source of drilling fluid, such as high pressure pumps, not shown. Conduit 18 is connected to a generally inverted can shaped seal member 24 of a type known in the art. The seal member 24 may be a commercially available external or internal seal, fillup and circulating tool such as an Autoseal tool available from Weatherford or an FC fillup and circulating tool available from Frank's International.
A somewhat flexible, thick walled, reinforced [0026] hose type conduit 26 depends from the casing seal member 24 and is in communication with the conduit 18 for receiving drilling fluid therefrom. However, conduit 26 may in certain operations be connected directly to conduit 18 and seal member 24 omitted. The lower end of conduit 26 is connected to a coupling 27 which is connected to a mandrel member of a mudsaver valve in accordance with the invention, which valve is generally designated by the numeral 28. Prior to insertion of casing section 10 fully into a wellbore, the mudsaver valve 28 is lowered into the casing section 10 sufficiently to allow the valve to open, as will be fully understood from reading the description of the valve hereinbelow. When conduit 26 is lowered sufficiently to cause valve 28 to be fully inserted in casing section 10 and the valve caused to open, drilling fluid is pumped into the casing section or sections to fill same with such fluid. Subsequently conduit 26 and seal 24 are lowered further until the seal 24 engages the upper end 10 a of the casing section in a known manner so that drilling fluid can continue to be pumped from conduit 20 through conduits 18 and 26 and through the mudsaver valve 28 into and also through the interior of the casing section. When the casing section 10 has been lowered into a wellbore to a point just above the floor of the drilling rig, not shown, pumping of drilling fluid ceases and after equalization of fluid pressure in the casing section 10 and the conduit 26, the seal member 24 and mudsaver valve 28 are moved upwardly and withdrawn from the interior of the casing section in a known manner. The process described above is repeated, also in a known manner, as additional casing sections are added to a casing string being inserted into the aforementioned wellbore.
Referring now to FIG. 2, the [0027] mudsaver valve 28 is shown in a position wherein it has just entered the upper end 10 a of the casing section 10 but is not yet completely in its intended working position for circulating drilling fluid into the bore 11 of the casing section. The casing section 10 includes an upper collar portion or box 13 forming part of the upper end 10 a and having internal threads 13 a of larger inside diameter than the casing bore 11. The casing section 10 is of conventional construction.
[0028] Mudsaver valve 28 includes a generally cylindrical elongated valve body 30 having a longitudinal, central cylindrical bore 32 extending therethrough between an upper transverse endface 34 and a lower transverse endface 36. Cylindrical bore 32 intersects a conical bore part 38 which opens to the lower endface 36. Valve body 30 is also provided with three circumferentially spaced elongated rectangular cross section slots 40, see FIG. 3 also, for receiving three circumferentially spaced respective so-called drag blocks 42, as shown in FIGS. 2 and 3, which drag blocks project radially outwardly and are operable to forcibly engage the borewall 11 of casing section 10. The section view of FIG. 2 has been rotated into the plane of the paper to show two of the drag blocks 42. Each of the drag blocks 42 is characterized as a generally rectangular member preferably formed of a urethane composition and is provided with an axially sloped outer surface portion 43, as shown in FIG. 2. Each of the drag blocks 42 is retained in its slot 40 by a suitable threaded fastener 44, FIG. 2, having a head portion 46 disposed in a recess 47. The drag blocks 42 are also each provided with spaced apart spring receiving bores 49, as shown in FIG. 2, for receiving respective coil biasing springs 50 therein. Biasing springs 50 are engageable with the valve body 30 and are sleeved over suitable guide pins 52 mounted on the body 30 and projecting radially outwardly therefrom. Guide pins 52 are slidably disposed in cooperating bores 54 formed in the drag blocks 42, as shown, to assist in guiding and centralizing the blocks so that the blocks may move radially inwardly and outwardly with respect to a longitudinal central axis 55. Accordingly, the drag blocks 42 are adapted to frictionally engage the borewall 11 as the mudsaver valve 28 is inserted into the upper end of casing section 10, and may be urged radially inwardly as the surfaces 43 engage the borewall 11 and remain forcibly engaged with the borewall for a purpose to be described further herein.
Referring further to FIGS. 2 and 3, the [0029] mudsaver valve 28 includes an elongated, generally cylindrical closure member 60 disposed in bore 32 and suitably secured to a conically shaped guide nose 62 disposed on the lower end of the closure member. The closure member 60 is provided with an externally threaded upper end part 63 suitably connected to an elongated cylindrical tubular mandrel 61, as shown. Mandrel 61 is connected to conduit 26 via coupling 27, see FIGS. 1 and 4. The closure member 60 includes a central longitudinal flow passage 65 in fluid flow communication with mandrel 61 and extending from the upper end 63 to axially inclined fluid discharge ports 66 which open to the outer cylindrical surface 67 of the closure member between spaced apart annular, elastomer lip type seals 69. The seals 69 are disposed in suitable annular grooves 70 and 72 on the closure member 60 spaced apart on opposite sides of the points at which the ports 66 intersect the surface 67 of the closure member 60.
In the position of the [0030] mudsaver valve 28 shown in FIG. 2, the closure member 60 is in a valve closed position and fluid flow out of the mudsaver valve is blocked by the position of the closure member 60 relative to the valve body 30. There are no substantial resultant pressure fluid forces acting on the closure member 60 tending to bias it in the open position or in the closed position shown, due to the configuration of the ports or passages 66 and the arrangement of the seals 72 when the closure member is in the valve closed position. However, when the mudsaver valve 28 is inserted into a casing section, such as the casing section 10, the drag blocks 42 will forcibly engage the borewall 11 permitting only limited entry of the body 30 past the intersection of the borewall 11 with the enlarged diameter bore which includes internal threads 13 a. Continued downward movement of the conduit 26 and the structure connected thereto will cause the closure member 60 to move downward to the position shown in FIG. 4 wherein the ports 66 are open to the interior passage 11 a of the casing section 10. Drilling fluid may then flow down through conduit 26, mandrel 61 and closure member 60 into casing section 10.
As shown in FIG. 4, the [0031] valve body 30 has entered the casing section 10 only a relatively short distance below the intersection of the bore 11 with the bore formed by the internal threads 13 a of the upper end 10 a of the casing section. Valve body 30 is preferably provided with one or more upwardly extending elongated spring steel position indicator or “telltale” fingers 73, FIG. 4, to indicate when the body 30 is sufficiently inserted in casing section 10. Indicator fingers 73 are suitably connected to the upper end of body 30 adjacent end face 34, as shown in FIG. 2. Accordingly, when it is desired to circulate drilling fluid through the casing section 10, the mudsaver valve 28 and conduit 26 are inserted in the upper end 10 a and move downwardly until indicator fingers 73 disappear within the casing section. Conduit 26 is moved further downward to assure that valve 28 has moved to the open position and conduit 26 may also, when fluid circulation is to commence, be moved downward until the seal 24 extends over the upper end of the casing section 10 in a known manner. At this time, the body 30 has only moved a short distance into the casing section 10, as shown in FIG. 4, but the closure member 60 has extended to the position shown to allow free flow of drilling fluid through the passage 65, the ports 66 and into the casing bore.
When it is desired to withdraw the [0032] mudsaver valve 28 from the interior of the casing section 10, the aforementioned traveling block raises the swivel 12 and the conduit assembly connected to the mudsaver valve whereby the closure member 60 will move upwardly relative to the body 30 until flange 62 a of nose 62 engages the lower end face 36 of the body and the closure member is fully seated within the body.
Thanks to the conically tapered bore [0033] 38, the seals 69 are guided into fluid tight sealing engagement with the body 30 at bore 32 as the closure member 60 moves into the bore from the valve open position to the valve closed position shown in FIG. 2. Accordingly, since the body 30 is frictionally engaged with the casing section 10 by way of the drag blocks 42, the closure member 60 moves to the valve closed position before the mudsaver valve 28 is withdrawn from the casing and only a negligible amount of drilling fluid may spill out of the upper end of the casing section 10 as the circulating assembly shown in FIG. 1 is withdrawn from the casing section.
Still further, once circulation of drilling fluid from [0034] conduit 20 down through conduits 18 and 26 has ceased and while the closure member 60 is still in the position shown in FIG. 4, pressures in the casing bore 11 and the conduits of the circulating assembly are essentially equalized so that when the seal 24 is moved off of the upper end 10 a of the casing section, there is no rapid discharge of pressure fluid from the casing. Of course, if rig operating personnel detect substantial pressure in the conduits leading to the casing section 10 prior to withdrawal of the mud circulating assembly from the casing section, the seal 24 and mudsaver valve 28 will not be removed from the casing section until pressures can be substantially reduced and equalized between the conduit 26 and the casing section 10, for example.
Referring now to FIG. 5, a first alternate embodiment of a mudsaver valve in accordance with the invention is illustrated and generally designated by the numeral [0035] 128. The mudsaver valve 128 is shown inserted within a casing section 10 and includes a closure member 60 slidably disposed in a modified valve body 130 and connected to a tubular mandrel 161 which is connected to conduit 26 via a coupling 27. Valve body 130 is configured generally like valve body 30 and includes a cylindrical longitudinal central bore 132 extending between an upper endface 134 and a lower endface 136. Bore 132 intersects a conical bore 138 which opens to the lower end face 136 of the valve body 130 for the same purpose as the conical bore 38. Valve body 130 includes a cylindrical reduced diameter recessed section 135 between the upper end face 134 and the lower end face 136 for supporting a friction or drag assembly, generally designated by the numeral 140.
The [0036] drag assembly 140 includes four, circumferentially spaced longitudinally extending cantilever spring fingers 142 which are mounted on a hinged collar 144, see FIGS. 6 and 7 also. The collar 144 comprises opposed arcuate collar members 144 a and 144 b which are hinged together at a hinge pin 148. Collar members 144 a and 144 b include spaced apart interfitting latch members 145 and 147 which are alignable to receive a latch pin 150. Collar members 144 a and 144 b may be latched in a collar closed position by pin 150 when fitted snugly over the reduced diameter section 135 of body 130. The friction or drag assembly 140 may be selected in accordance with the diameter of the casing bore 11 so that the mudsaver valve 128 may be used with various casing sizes and requiring only that the drag assembly 140 be substituted for a drag assembly having spring fingers of suitable dimensions to provide the requisite resistance to movement through the casing section so as to allow the closure member 60 to move relative to the body 130 in the manner generally as described for the mudsaver valve 28. Moreover, the spring fingers 142 serve as their own telltale or position indicators for determining if the body 130 is sufficiently inserted within the casing section 10.
Referring further to FIGS. 6 and 7, the [0037] drag assembly 140 is shown with a configuration of the cantilever spring fingers 142 which project upwardly and radially outwardly and have somewhat reentrant distal end parts 143. The spring fingers 142 may be formed of spring steel and are preferably covered or coated with a suitable plastic overlay, such as a urethane coating 146, to minimize any chance of damage to the threads 13 a of the casing section 10 when the mudsaver valve 128 is inserted into the casing. Preferably the body 130 may be inserted only to the extent that the spring fingers 142 forcibly engage the internal threads 13 a of the casing section and are thus partially visible from the upper end 10 a of the casing section during operation of the mudsaver valve and the circulating assembly.
In other words, as the [0038] mudsaver valve 128 is inserted into a casing section, such as the casing section 10, the valve body 130 is inserted until the upper ends 143 of the spring fingers 142 are visible just above the upper end 10 a of the casing section. Then, under operating conditions using the seal 24, as the seal is lowered and engaged with the upper end of the casing section, the operator of the circulating assembly is assured that the closure member 60 has moved downward to the position shown in FIG. 5 relative to the body 130.
Alternatively, the [0039] valve 128 may be inserted to the position shown in FIG. 5. The mudsaver valve 128 is thus operated in substantially the same manner as the valve 28 and is easily withdrawn from the casing section 10 by merely pulling up on the circulating assembly, including the swivel 12, until the closure member 60 moves to the closed position relative to the body 130 and further upward movement results in the cantilever spring fingers 142 sliding upward in frictional engagement with the casing section so that the valve 128 can be withdrawn from the casing in its closed position.
Referring now to FIGS. 8 and 9, a second alternate embodiment of a mudsaver valve in accordance with the invention is illustrated and generally designated by the numeral [0040] 228. The mudsaver valve 228 utilizes the closure member 60 and the mandrel 61 suitably connected to the conduit 26, not shown, by way of the coupling 27. A modified body 230 includes a suitable central axial bore 232 for receiving the closure member 60 in the same manner that the body 30 receives the closure member 60 of the embodiment of FIGS. 1 through 4. Valve body 230 includes central axial bore 232 and a tapered bore portion 238 at the lower end thereof, as illustrated in FIGS. 8 and 9. Accordingly, when the closure member 60 moves to a valve closed position, as shown in FIG. 8, from a valve open position, as shown in FIG. 9, the seals 69 are operable to provide fluid tight engagement with the bore 232 in the same manner as for the embodiments of the mudsaver valve previously described.
As shown in FIG. 8, the [0041] body 230 includes spaced apart circumferential flanges 231 and 233 between which is secured a hinged collar 144 for a modified drag assembly 240. Drag assembly 240 further includes a second hinged collar 144 secured to a generally spool-shaped body member 245 which includes a central axial bore 246 for receiving the mandrel 61 in axial sliding engagement therewith. The upper hinged collar 144 is disposed on the body 245 between opposed circumferential flanges 245 a and 245 b. The upper and lower hinged collars 144 are suitably connected to opposite ends of circumferentially spaced elongated spring steel drag members 242, similar to the spring finger drag members 142, but secured at their opposite ends to the respective hinged collars 144 and adapted to retain a somewhat radial outward projecting bow shape, as shown. Accordingly, a selected drag assembly 240 may be mounted on the mudsaver valve 228, depending on the diameter of casing in which the mudsaver valve is to be inserted, so that the drag members 242 may engage the bore wall of the casing with sufficient frictional drag to allow the closure member 60 to move downward out of the body 230 sufficiently, as shown in FIG. 9, to uncover the ports 66 so that fluid may flow into a casing section, not shown in FIGS. 8 and 9, in which the mudsaver valve 228 has been inserted.
Referring also to FIGS. 10 and 11, further details of the [0042] drag assembly 240 are illustrated. Each of the hinged collars 144 is secured in its closed position by pins 148 and 150, as shown, and each of the drag members 242 may include a suitable elastomer coating 246 formed thereon, such as the aforementioned urethane coating used for the spring fingers 142 of the drag assembly 140.
When the [0043] mudsaver valve 228 has been inserted into a casing section, such as the casing section 10, not shown in FIGS. 8 and 9, the drag members 242 will engage the casing bore wall sufficiently to allow the closure member 60 be moved to the position shown in FIG. 9 upon downward movement of the conduit 26, coupling 27 and mandrel 61. The mudsaver valve 228 may be moved to the closed position by pulling up on the conduit 26, coupling 27 and mandrel 61 until the closure member 60 has moved to the position shown in FIG. 8 whereupon the mudsaver valve 228 may be withdrawn from a casing section. One advantage of the mudsaver valve 228 resides in the arrangement of the drag assembly 240 with respect to the coupling 27. As shown in FIG. 9, as the mandrel 61 and coupling 27 move downward relative to the body 230, the coupling 27 may engage the body 245 to assure that the body and drag assembly 240 are fully inserted into the upper end of a casing section. Accordingly, upon withdrawal of the mudsaver valve 228 from a casing section the closure member 60 will move back into the body 230 before the valve is removed from the upper end of the casing.
The construction and operation of the [0044] mudsaver valves 28, 128 and 228 is believed to be readily understandable to those of ordinary skill in the art based on the foregoing description. Conventional engineering methods and materials for mudsaver valves may be used in fabricating the valves 28, 128 and 228. Although preferred embodiments of a mudsaver valve in accordance with the invention have been described in detail herein, those skilled in the art will also recognize that various substitutions and modifications may be made without departing from the scope and spirit of the invention as recited in the appended claims.

Claims

What is claimed is:

1. A mudsaver valve for use in well operations comprising:

an elongated valve body member including an axial cylindrical bore therein;

an elongated, generally tubular closure member disposed in said bore in said body member, said closure member including an elongated axially extending passage formed therein and passage means opening to an outer surface of said closure member, said closure member being movable axially in said bore in said body member between valve open and closed positions; and

at least one drag member connected to said body member and engageable with a wall of a well conduit upon insertion of said valve into said well conduit for holding said body member substantially stationary with respect to said well conduit to permit opening and closing said valve by moving said closure member axially in said bore of said body member.

2. The valve set forth in claim 1 including:

spaced apart seals on one of said body member and said closure member for preventing flow of fluid from said passage means in said closure member in the valve closed position of said closure member.

3. The valve set forth in claim 2 wherein:

said seals comprise annular seal members mounted on said closure member and engageable with a borewall of said bore in said body member.

4. The valve set forth in claim 3 including:

a tapered bore part extending from one end of said body member and intersecting said bore in said body member for engaging said seals when said closure member moves from a valve open position to a valve closed position.

5. The valve set forth in claim 1 wherein:

said closure member is connected at one end to an elongated conduit for conducting fluid to said passage in said closure member from a source of said fluid.

6. The valve set forth in claim 1 including:

a tapered guide member disposed on one end of said closure member for guiding said valve into said well conduit.

7. The valve set forth in claim 1 wherein:

said drag member comprises plural circumferentially spaced drag blocks mounted on said body member for limited movement relative to said body member and operable to engage a wall of said well conduit.

8. The valve set forth in claim 7 including:

resilient biasing means for yieldably biasing said drag blocks radially outwardly into forcible engagement with said wall.

9. The valve set forth in claim 8 wherein:

said resilient biasing means comprises spring means interposed said drag blocks and said body member, respectively.

10. The valve set forth in claim 7 wherein:

said drag blocks each include an axially tapered outer surface formed thereon engageable with said well conduit for camming said drag blocks radially inwardly toward said valve body in response to urging said valve body into said well conduit.

11. The valve set forth in claim 1 wherein:

said drag member comprises a drag assembly including plural circumferentially spaced spring members supported on said body member and engageable with said wall of said well conduit upon insertion of said valve into said well conduit.

12. The valve set forth in claim 11 wherein:

said spring members comprise elongated cantilever spring fingers radially deflectable in response to engagement with said wall of said well conduit and operable to extend partially from an upper end of said well conduit in response to insertion of said valve into said well conduit.

13. The valve set forth in claim 11 wherein:

said spring members are mounted on a support collar adapted to be removably mounted on said body member.

14. The valve set forth in claim 13 wherein:

said collar includes opposed arcuate collar members joined together by a hinge and by a latch for mounting said collar on said body member and removing said collar from said body member, respectively.

15. The valve set forth in claim 11 wherein:

said spring members comprise elongated bow springs radially deflectable in response to engagement with said wall of said well conduit.

16. The valve set forth in claim 15 wherein:

said spring members are connected at one end to a first support collar adapted to be mounted on said body member and said spring members are connected at an opposite end to a second support collar mounted on another body member moveable relative to said body member and relative to an elongated mandrel connected to said closure member.

17. The valve set forth in claim 16 wherein:

said collars each comprise opposed collar members movable relative to each other for mounting and demounting said drag assembly with respect to said body members.

18. The valve set forth in claim 1 including:

an indicator member extending from said body member and operable to extend out of an upper end of said well conduit when said body member is disposed in said wall conduit.

19. A mudsaver valve for use in well operations comprising:

an elongated valve body member including an axial cylindrical bore therein;

an elongated closure member disposed in said bore in said body member, said closure member including passage means opening to an outer surface of said closure member, said closure member being movable axially in said bore in said body member between valve open and closed positions; and

a drag assembly connected to said body member and engageable with a wall of a well conduit upon insertion of said valve into said well conduit, said drag assembly including plural circumferentially spaced spring members supported on said body member and engageable with said wall of said well conduit for holding said body member substantially stationary with respect to said well conduit to permit opening and closing said valve by moving said closure member axially in said bore of said body member.

20. The valve set forth in claim 19 wherein:

said spring members comprise elongated cantilever spring fingers radially deflectable in response to engagement with said wall of said well conduit.

21. The valve set forth in claim 20 wherein:

22. The valve set forth in claim 21 wherein:

said collar includes opposed arcuate collar members joined together by a hinge and a latch for mounting said collar on said body member and removing said collar from said body member, respectively.

23. The valve set forth in claim 19 wherein:

24. The valve set forth in claim 23 wherein:

25. The valve set forth in claim 24 wherein:

26. The valve set forth in claim 19 including:

spaced apart annular seal members mounted on said closure member and engageable with a borewall of said bore in said body member for preventing flow of fluid from said passage means in said closure member in the closed position of said closure member.

27. The valve set forth in claim 26 including: