US3173502A

US3173502A - Rotating control head

Info

Publication number: US3173502A
Application number: US66304A
Authority: US
Inventors: Terry A Overby
Original assignee: Individual
Current assignee: Individual
Priority date: 1960-10-31
Filing date: 1960-10-31
Publication date: 1965-03-16
Anticipated expiration: 1982-03-16

Description

March 16, 1965 T. A. ovERBY 3,173,502

ROTATING CONTROL HEAD March 16, 1965 T. A. ovERBY ROTATING CONTROL. HEAD 2 Sheets-Sheet 2 Filed Oct. 31. 1960 IN V EN TOR. TERRY OVERBY United States Patent O 3,173,502 ROTATING CONTROL HEAD Terry A. Overby, 325 W. Delaware, Nowata, Okla. Filed Oct. 31, 1960, Ser. No. 66,304 Claims. (Cl. 17E-210) This invention relates to improvements in well drilling apparatus, and more particularly, but not by way of limitation, to a novel rotary fluid control head.

One of the more successful advancements in well drilling in recent years has been the use of air or gas as the circulating medium. The use of air or gas has been employed mainly where there has been a possibility of injury to the producing zone by liquid penetration or where there has been a loss of circulation. Other reasons for the use of air or gas have been to provide greater drilling speed and longer bit life. However, this new well drilling procedure has been subject to certain problems. It has` been found that it is necessary to provide etiicient seals around the rotating drill string and other portions of the well drilling apparatus to preclude any air leakage during the drilling operation since air or gas escape much more easily than Ia liquid and it is essential that there be no loss in pressure. Also, since it is necessary to occasionally change the drill bit to insure an optimum drilling speed, the sealing structure used must be readily disassembled to permit the changing of the bit without undue delay of the drilling operation. The sealing structure must be readily adaptable to the use of a liquid as the circulating fluid, as well as air or gas, since during the drilling of a well bore it may become necessary to change from one fluid to another.

The present invention contemplates a novel rotary control fhead which provides an efcient static seal between the drill stem and a portion of the control head rotating simultaneously therewith. An efhcient dynamic seal is also provided between the stationary and rotating portions of the control head -to preclude fluid leakage therethrough, regardless of Whether liquid mud or air is utilized as the circulating fluid. The rotary control head may be partially disassembled during the well drilling operation to service or replace the drill bit as the circumstances may require without the necessity of completely disassembling the control head or disturbing the set up of the rotary table. A fluid seal is also provided between the control head and the casings positioned in `the well bore so that all possibilities of fluid leakage are substantially precluded, since it is mandatory that a -control head utilized in air drilling be substantially leak proof.

An important object of this invention is to provide a novel control head particularly designed and constructed to efficiently pack off a rotating drill string during a well drilling operation.

Another object of this invention is to provide a novel control lhead which provides an efficient static seal between a rotating drill string and the rotary portion of the control head.

A further object of this invention is to provide a novel control head which provides an efficient dynamic seal between the stationary and rotating portions of said control head.

A still further object of this invention is to provide a control head which efficiently packs off the control head from the well casing.

And yet another object of this invention is to provide a control head which permits a drill bit depending from a drill stem to be easily serviced without completely disassem'bling Iand removing the control head from a derrick structure.

And a still further object of this invention is to provide a control head that is simple and inexpensive in construction and which is of great utility in both large and small applications.

3,173,502 Patented Mar. 16, 1965 ICC Other objects and advantages of the invention will be evident from the following detailed description, read in conjunction with the accompanying drawings, which i1- lustrate my invention.

In the drawings:

FIGURE 1 is a side elevational view of the novel fluid control head.

FIGURE 2 is a longitudinal sectional view of the control head shown in FIG. l.

FIGURE 3 is a longitudinal section depicting a modification of the novel control head.

FIGURE 4 is a sectional View taken along line 4--4 of FIG. 3.

FIGURE 5 is van enlarged sectional elevational view of a portion of the control head device, partly in section, and particularly depicting a drill stem and drill bit in yassociation therewith.

Referring in detail to the drawings, and in particular fto FIG. 2, reference character 10 generally designates a novel rotary fluid control head preferably of a substantially tubular conguration. The control head 10 comprises a tubular body member 14 provided with outwardly extending

flanges

16 and 18 secured to the opposed ends thereof. A sleeve member 20 `having an outwardly extending flange 22 provided on its lower end is disposed immediately adjacent to the upper flange 16 of the tubular body 14. The upper flange 16 of the tubula-r body 14 is secured to the lower flange 22 of sleeve 20 in any well known manner, although ange 16 is preferably secured to flange 22 by any suitable connection members 21 which permit the

flanges

16 and 22 to be quickly disengaged when it is so desired. The connection members 21 may be suitable wedge pins and are secured to the body 14 by a ychain 23 to preclude any accidental loss thereof in the disengaged position of the pins.

A plurality of outwardly extending flanges or lugs 24 are provided ron the upper portion of the sleeve member 20 so that the sleeve 20 may be suspended from the stationary members 26 (shown in dotted lines in FIG. 2) by any suitable means, such as hooks or hangersI 27 (FIG. l). The members 26 are preferably a portion of the substructure of the well drilling rig (not shown) and always rem-ain stationary, regardless ofthe rotation of the rotary table or the drill string. The tubular body 14 is connected with the support member 26 and thus is a stationary portion of the rotary control head 10.

The tubular member 2@ is further provided at its upper portion with an inwardly extending circumferential shoulder 2S which cooperates with a sleeve 30 extending through the central bore 32 of the sleeve 20 to define an annular -cavity 34 therebetween. The sleeve 30 rotates within the stationary sleeve 20 during the drilling operation, as will be hereinafter set forth. A plurality of suitable annular sealing rings 36, preferably chevron rings, or the like, but not limited thereto, are disposed in the cavity 34 to provide a dynamic seal between the rotatable sleeve 30 and the router tubular member 20. An annular retaining ring 38 is threadedly secured to the inner bore 32 of the sleeve 20 at the lower portion thereof to support the chevron seals 36 within the sleeve cavity 34 and to position the seals 36 therein so that the seals Contact ythe outer periphery of the rotatable tubular member 3G withan optimum sealing pressure. It is understood that although the seals 36 lare shown as being chevron sealing rings, applicants novel rotary control head is not restricted to the specific use tof chevron sealing rings and another suitable packing could be substituted therefor. A radial passageway or port 40 is provided in the sleeve 2t) to receive a suitable lubricant fitting 42 whereby a suitable lubricant of any Well known ltype may be directed into the chamber 34 for lubrication of the 4sealing rings of packing 36. It is preferable that the lubricant comprise an oil that is supplied under pressure.

A sleeve member 46 having an outwardly extending flange 48 on its upper portion is positioned below and adjacent to the lower flange 1S of the body 14 in order that the flange 48 may be secured 'to the flange 18 in any ell known manner, preferably in the manner utilized in the connection of the flange 16 of sleeve 14 and flange 22 ofsleeve 2t). The sleeve 14 is provided with an aperture 47 to provide communication with a tubular member 50 secured to the outer periphery of the sleeve 14 around the aperture in order that a return fluid flow from the well bore may be directed through the aperture 47 into the tube 50 for discharge to the slush pits, as will be hereinafter set forth.

The rotatable sleeve is secured at its upper portion to a drive bushing 52 in any well known manner, such as welding or the like, but not limited thereto. The drive bushing 52 is connected in any Well known manner to a rotary table 54 (shown in dotted lines in FlG. 2) provided on the substructure of a drilling derrick (not shown). The rotation of the rotary table 54 is imparted to the rotatable sleeve 30 through the drive bushing 52, as is well known. The drive bushing 52 and rotary table 54 are shown only generally since they do not constitute an essential portion of applicants invention and can be construed in accordance with general design procedures. VThe rotatable tubular member 30 has a sleeve member 56 (FIG. 2) threadcdly secured to the lowermost portien thereof for a purpose to be hereinafter set forth. The vsleeve member 56 extends divergingly outward from the lower portion of the sleeve 30 whereby the diameter of the inner bore of the sleeve 56 is greater at its lower than at its upper portion. A circumferential shoulder or Aflange SSextends radially outwardly from the lower portion of the sleeve 56 and is provided with an annular concave recess 60 on the bottom portion thereof for receiving a sealing member or stripper 62. The sealing member 62 is preferably of a substantially circular conguration and is constructed of a suitable resilient or flexible material, such as neoprene, rubber or Ithe like, and is provided with a substantially circular bead 64 formed on the outer edge thereof complementary to the groove 69 of the flange 58. The upper portion of the bead 64 is positioned within the complementary recess "66 of the flange 58 and an annular supporting ring 66 having a similar complementary recess 68 is positioned against the bottom portion of the ring 62 so that the resilient member 62 is clamped therebetween. A plurality of bolts 70 or other sealing means extend through the flange 58 of the sleeve 56 and the supporting ring 66 for securing Athe sealing member 62 securely in position at the lower portion of the sleeve 56. A central bore or aperture 72 is provided in the resilient member 62 in order that a drill stem or kelly 73 may be extended therethrough, as is well known. The diameter of the bore 72 is sufficiently smaller than the outer diameter of the drill string whereby a tight static seal may be provided between the drill string and the sealing member 62 to substantially preclude any leakage of circulating fluid therebetween. The drill string is secured to the kelly in any well known manner for rotation therewith as is the usual practice in the drilling of a Well bore.

The seal member 62 is shown herein as being a design which efficiently seals around any kelly or drill stem 73 passing therethrough and that allows for flexing either upwardly or downwardly as the drill stem is moved relative thereto to preclude rupturing of the seal member. However, it is understood that although the stripper 62 is a preferred embodiment, the control head depicted herein is not restricted to a specific use thereof and conditions may be encountered which deem it advisable to use another stripper of any well known type. It is also considered to be within the scope of this invention to secure a second stripper member (not shown) of suitable design to the bottom portion of the ring 66 to preclude cuttings from the well bore contacting the stripper 62 and to enhance the sealing properties thereof.

The drill stem 73 normally extends downwardly through the sleeve 36, the static sealing member 62, the sleeve 46 and into the well bore (not shown) during the drilling operation. Drilling fluid is usually circulated downwardly through the inner or central bore of the drill stem to the drill bit 75 for facilitating the drilling of the bore. The fluid is normally returned from the bottom of the well bore upwardly around the drill stem and into the

sleeves

46 and 14. The returning or circulating fluid is discharged from the sleeve 14 through the port 47 and is directed through the conduit 5) to the slush pumps (not shown) for recirculation into the bore of the drill stem. The sleeve 36 and the drill stem are both rotated by the rotary table 54s and thus, there is usually no relative rotation therebetween. The stripper or sealing member 62 provides a static seal between the sleeve 30 and the drill stem lto preclude any leakage of the fluid upwardly around the drill stem. The sleeve 14 is stationary, as hereinbefore set forth, and the packing members 36 provide a dynamic seal between the rotating sleeve 30 and the stationary sleeve 14. It will be apparent that the combined static and dynamic sealing of the control head f6 substantially precludes any leakage of fluid therethrough during the drilling of a well bore.

The sleeve 46 depending downwardly from the lower portion of the body 12 extends into the inner bore of the usual surface string 74 of the well bore. An annular collar 76 is threadedly secured to the upper portion of the surface string 74 by a suitable coupling member 77 and is provided with a sealing ring 78 disposed in an annular recess Si) on the inner periphery of the collar 76. The sealing ring '73 is preferably an O-ring, or the like, but not limited thereto, and cooperates with the outer periphery of the sleeve 46 to provide a fluid seal between the sleeve 46 and collar 76 to substantially preclude fluid leakage therebetween. The sleeve 46 also extends downwardly over the usual well casing 82 that is normally concentrically arranged within the surface string 74. An annular collar 84 is threadedly secured to the upper portion of the well casing 82 by means of any suitable coupling member Se', as is well known. An annular sealing ring 36 is disposed within an annular recess 88 provided on the outer periphery of the collar 84. The sealing ring 86 is in sealing contact with the inner periphery of the sleeve 46 to provide a fluid seal between the collar 64 and the sleeve 46 and to substantially preclude fluid leakage therebetween. The surface string 74, well casing 82 and coupling member 8S are standard equipment in well bores and are shown in dotted lines for purposes of illustration.

Since the well casing 82 is concentrically arranged within the surface string 74, an annular cavity 9d is formed between the casing 82 and the surface string 74. Thus, when it becomes desirable to change the drill bit 75 depending from the drill string 73, the flange 4S is disconnected from the flange 18 so that the sleeve 46 may be lowered with respect to the body 14. The sleeve 46 is lowered into the cavity 9) until the flange 48 contacts the collar 76. The drill stem is then moved upwardly through the control head it? until the drill bit is positioned immediately below the sealing member 62.. Since the sleeve 46 has been disconnected from the flange 18 and moved downwardly, the drill bit is readily accessible for service. However, during-the ordinary drilling of the well bore, the

seals

86 and 78 cooperate with the stationary sleeve 46 to substantially preclude any fluid leakage thereby and to maintain a constant fluid pressure within the well bore.

Referring to FIG. 3, reference character 92 generally designates a modified control head comprising a substantially tubular body 94. The tubular body 94y is provided air/ama with an upper outwardly extending circumferential llange 96 and a lower outwardly extending circumferential liange 9S. The anular flange 98 may be secured directly to the surface string 74 or it may be secured to the cylinder 46, as set forth in the preferred embodiment, and which is slidably positioned between the well casing 82 and the surface string *74, as clearly shown in FIG. l. The cylindrical body 94 is provided with an aperture 106 around which a cylindrical element 102 is positioned for a purpose which has been hereinbefore set forth. A sleeve 104 having in inwardly directed flange 166 at one end thereof and an outwardly directed flange 108 at the opposite end thereof is positioned on the upper portion of the tubular body 94. The circumferential flanges 1&8 and 96 are provided with a plurality of aligned apertures 110 which may be mated for receiving any suitable closure members, such as bolts 112.

A plurality of annular chevron sealing members 114, or any other suitable type of sealing members, such as are well known in the art, are positioned within the sleeve 104 and held therein by a retaining ring 116 threadedly secured to the lower end of the sleeve 164. Lubrication is supplied to the aforesaid sealing members 114 by means of a lubricant fitting 118 disposed in the side wall of the sleeve 104. As has been hereinbefore set forth, the lubricant is preferably an oil supplied under pressure, although any suitable grease may also be employed.

An annular flange 120 is bolted to the underside of the rotatable portion of the rotary table 54 (not shown in FIG. 3) for rotation therewith. The flange 120 is provided with a particularly configured recess 122 for receiving an outwardly extending flange 124 of a cylindrical body 126. The recess 122 and llange 124 cooperate to provide a substantially bayonet type connection. The flange 124 is preferably shaped to form a plurality, preferably three, outwardly extending ears 127 which cooperate with the particularly configured recess 122 for disposition therein as is clearly shown in FIG. 4. As shown in FIG. 4, the recess 122 is provided with three upwardly extending slots 128 for receiving the outwardly extending members 127 as the body 126 is moved downwardly through the flange 120. After the members 127 of sleeve 126 have been positioned within the recess 122, the sleeve 126 is rotated slightly and locked in position by any suitable means, such as a spring biased locking pin 13b which passes through the flange 126 into a locking position with the flange 124.

During operation of the novel control head 92, the sleeve v126 is positioned intermediately within the sleeve 104 so that it contacts the seal members 114 which provide a dynamic seal therebetween. Thus, the dynamic seal members 114 substantially preclude the leakage of the circulating fluid, either liquid or gas, and any cuttings carried thereby through the point of contact of the rotatable member 126 and the stationary body portion 94. The cylindrical member 126 is provided with an inwardly extending flange 132 for a purpose which will be hereinafter set forth. A sleeve 134 having an inwardly extending llange 136 at the upper portion thereof is disposed below the sleeve 126 and adjacent to the flange 132 in order that the llange 136 may be secured thereto by any suitable means, such as bolts 137. A static seal between the rotatable inner body member and a drilling string passing therethrough is provided by a resilient stripper rubber 140 secured to the lower end surface of the sleeve 134. A ring 142 is positioned beneath the stripper element 14@ and secured to the sleeve 134 by bolts 144, or the like, so as to iixedly secure the stripper 140 therebetween. As hereinbefore set forth in the description of the novel control head shown in FIG. l, it is within the scope of the invention to position yet another resilient stripping element (not shown) below the stripper 140 for the purpose of initially removing any cuttings carried by the outer periphery of the 5 drilling string when it is raised within the stationary body 94 thereby materially prolonging the active life of the stripper 140.

Operation Assuming that it is desirable to assemble the rotary control head 10 so that it will appear as in FIG. 2 for operation, it is iirst necessary to slip the sleeve 3@ over the lower end of the drill string 73 and secure it to the housing 52 whereby the sleeve 3i) may be rotated simultaneously with the drill stem bythe rotary table 54. It is assumed that the sleeve 20 has already been secured to the stationary members 26 by any suitable means, such as hooks or hangers, so that the sleeve 3d is initially moved upwardly through the central bore 32 of the sleeve 30 before it is secured to the bushing 52. The sleeve 46 is then moved downwardly within the cavity between the well casing 82 and the surface string 74 until the flange 4g abuts the collar 76 connected to the upper portion of the surface string 74. The tubular body 14 is then moved upwardly over the lower portion of the drill stem into a position wherein its integral flange 16 may be secured to flange 22 of the sleeve body 2l) in any suitable manner, such as vby the lugs 21 or by a threaded connection (not shown). It will be apparent that the drill bit 75 may be secured to the lower end of the drill stem since the sleeve 46 is in the lowered position for providing access to the drill stern. The sleeve 46 is then moved upwardly within the cavity 90 and secured to the flange 18 of the body 14 in a manner similar to that utilized in the connection of

flanges

22 and 16. However, it is understood that it may be desirable to have different means of connecting the

flanges

16 and 18 to their respective members so that the invention is not limited to the use of the same connecting means in both instances. The drill bit 75 is then moved downwardly within the sleeve 46 into the well casing 82 for the drilling of the well bore.

As the drill string is rotated within the well bore by the rotary table 54, the sleeve 30 is simultaneously rotated therewith so that there is no relative rotation between the circular seal member 62 and the drill string. The bore extending through the sealing member 62 closely lits the outer periphery of the drill string so that there is susbtantially no liuid leakage therebetween, regardless of whether the circulating fluid being utilized is either liquid or air. Thus, the novel rotary control head provides an eiiicient static seal between the rotating drill pipe and the rotating portion of the control head.

The packing or chevron seals 36 disposed in the annular cavity formed between the sleeve 20 and the sleeve 30 are in sealing contact with the outer periphery of the sleeve 39 as it is rotated with the drill string, thus providing an eliicient dynamic seal between the rotating sleeve 3? and stationary sleeve 26 whereby leakage of the circulating uid therebetween may be substantially precluded.

The packing or O-ring 8i) that is carried by the collar 76 secured to the surface string 74 also contacts the outer periphery of the sleeve 46 in sealing position. The packing or O-ring 86 that is carired by the collar 88 connected to the upper portion of the well easing 82 also cooperates with the inner periphery of the sleeve 46 to provide a seal therebetween and to substantially preclude iiuid leakage. Thus, the circulating fluid present in the well bore is precluded from leakage past the point of contact of the sleeve 46 with the collars of the surface string and the well casing by the cooperation of the seals 81B and 86 with the sleeve 46. If the ordinary form of fluid circulation is utilized, the fluid passes downwardly through the drill string and then moves upwardly around the drill string and through the well casing 82 until it passes through the aperture 47 in the body 14 of the control head 10 and into the tube 5t) for recirculation through the well bore.

When it is necessary to replace the drill bit, the drill string is pulled or moved upwardly within the well bore until the drill bit is adjacent to and spaced directly below the sealing member 62 carried by the sleeve 56. As the drill string is moved upwardly within the well bore, the seal member 62 exes upwardly around the outer periphery of the drill strinfT so that `any possibility of rupturing or tearing of the seal member 62 by the string as it is pulled upwardly therethrough may be materially reduced. The fluid circulation is, of course, halted during this period so that the control head is free of any circulating uid. When the drill bit is positioned below the sealing member 62, the ange 43 of the sleeve 46 is then disengaged from its connection with the llange 18 of the body 14 by removing the bolts or other securing means used to secure the two flanges 18 and i3 together. The sleeve 46 is then moved downwardly within the annular space 90 between the surface string 74 and the well casing 82 until the ilange 48 iabuts the upstanding collar secured to the upper portion of the surface string 74. The drill bit is then positioned between the lower portion of the tubular body 14 and the flange-d portion 48 of the sleeve 46 so that it may be readily serviced or replaced as the circumstances may require. The control head may be partially disassembled while in place for service or removal of the drill bit `and also provides elicient sealing of the rotating drill stem without the necessity of cornpletely removing or disassembling the contr-ol head when it is necessary to remove the drill bit.

The operation of the modilication of the novel rotary control head shown in FlGS. 3 and 4 is substantially similar to the operation of the preferred form of the invention as hereinbefore set forth. The ilange 120 is initially bolted or otherwise secured to the bottom of the rotary table before the sleeve 126 is moved downwardly within the rotary table and secured to flange 120 by a locking means, such as pin 130, engaging the ear 127 of the sleeve 126. The body portion 94 is assembled and positioned below the flange 12() so that when the sleeve 126 is moved downwardly within the flange 120, it will pass through the sleeve 1&4 carrying the packing members 114 and establish a sealing contact therewith. The body portion 94 may be secured in any well known manner (not shown) to the surface string or a blow-out preventer (not shown) which may be selectively positioned therebelow. Prior to the locking of sleeve 126 in flange 120, a portion of a drill string is passed through the stripper rubber 140 so that a suitable drill bit may be secured to the bottom portion thereof. The drill bit is chosen so that its greatest diameter is no greater than the diameter of the sleeve 126, thereby allowing the drill string with the depending drill to be withdrawn from the control head with the sleeve 125.

When the drill bit becomes worn or it is otherwise necessary to service it, the locking means 130 is moved to allow the ears 127 of the sleeve 126 to be rotated into position so that the sleeve 126 `and the drill string passing therethrough may be moved upwardly. Since the drill bit is of less diameter than the sleeve 126, it may be withdrawn with the sleeve through the dynamic seal 114 and the flange 126 to the surface of the rotary table where it may be replaced or serviced. As in the form or" the invention shown in FlGS. 1 and 2, the seal members 114 furnish a dynamic seal between the stationary and the rotating portions of the control head and the stripper rubber 140 furnishes a static seal between the drill string and the rotating portion of the control head. In the modiiication of the invention shown in FGS. 3 and 4, the rotating portion is removed from contact with the stationary body portion, whereas in FIGS. l and 2, the invention shown therein has the stationary portion of the invention lowered from contact with the rotating portion for service of the drill bit.

From the foregoing, it is apparent that the present invention provides a novel rotary control head that elliciently packs off a rotating drill string from the well casing and substantially precludes any leak-age of the circulating fluid by furnishing a dynamic seal between the rotating and non-rotating portions of the control head and a static seal between the drill string and the head portion rotating simultaneously therewith. It is also apparent that the novel control head may be partially disassembled quickly to allow service of the drill bit without completely disassembling the control head and the attendant structure. The subject control head is ellicient in operation, simple and economic in construction, and exible in use that it may be employed in lapplications wherein liquid mud and air are used interchangeably.

Changes may be made in the combination and arrangernent of parts as heretofore set forth in the specification and `shown in the drawings, it being understood that any modification in the precise embodiment of the invention may be made within the scope of the following claims without departing from the spirit of the invention.

I claim:

1. A rotary control head for a drill string and cornprising a stationary body member, a sleeve member extending into the body member and rotatable with the drill string, static seal means interposed between the sleeve and the drill string, dynamic seal means interposed between the stationary body and the sleeve, passageway means for discharge of lluid from the control head, a pair of concentric annular collars having `an annular space therebetween and spaced from the stationary body, a sleeve member removably secured to the Ilower end of the stationary body and reciprocally disposed in the annular space between the collars to provide for access to the drill string without a complete disassembly of the control head, seal means interposed between the movable sleeve and the collars for precluding leakage of fluid therebetween, and means provided for limiting the downward reciprocal movement of the removable sleeve.

2. A rotary control head for a drill string and comprising a stationary body member, a rotatable sleeve disposed around the dril-l string and extending into the body member, static seal means interposed between the Sleeve and the drill string, dynamic `seal means interposed between the stationary body and the rotatable sleeve, passageway means for discharge of fluid from the control head, a pair of concentric annular collars having an annular space therebetween and spaced from the stationary body, a sleeve member removably secured to the lower end of the stationary body and reciprocally disposed within the annular space to provide for access to the drill string without la complete disassembly of the control head, means provided for limiting the downward reciprocal movement of the removable sleeve, and seal means precluding leakage or^ lluid between the collars and the removable sleeve.

3. A rotary control head for a drill string, and comprising a stationary body member, a sleeve concentrically disposed Within the body member and rotatable with the drill string, static seal means interposed between the rotatable sleeve and the drill string, dynamic seal means interposed between the stationary body and the rotatable sleeve, a pair of concentric collars having an annular space therebetween and spaced from the stationary body, a second sleeve removably secured to the lower end of the stationary body and in substantial alignment with the rotatable sleeve for receiving the drill string therethrough, said second sleeve extending into the annular space and reciprocal with with respect to the stationary body and collars to permit access to the drill string without a cornplete disassembly of the control head, means provided for limiting the downward reciprocal movement of the removable sleeve, seal means to preclude leakage of uid between the removable sleeve `and the collars, and passageway means for discharge of fluid from the control head.

4. In `combination with a well casing, and a drill string, a rotary control head comprising a stationary body member, a sleeve disposed around the drill string and rotatable therewith, static seal means interposed between the sleeve and the drill string, dynamic seal means interposed between the stationary body land the rotatable sleeve, prassageway means `for discharge of lluid from the control head, a `sleeve member removably secured to the lower end of the stationary body and reciprocally disposed within 'an annular space surrounding the well casing to permit access to the drill string without a complete disassembly of the control head, means provided for limiting the downward reciprocal movement of the removable sleeve around the well casing, and seal means interposed between the reciprocal sleeve and the well casing.

5. In combination with a well casing and a drill string, a rotary control Ihead comprising a stationary body member for receiving the drill string therethrough, .a sleeve concentrically disposed within the body member and around the drill string, said sleeve rotatable simultaneously with the drill string, static seal means carried by the sleeve for precluding leakage of fluid around the drill string, dynamic seal means carried by the stationary body member for precluding leakage of uid around the rotatable sleeve, a second sleeve removably secured to the stationary body for receiving the drill string therethrough, said second sleeve extending downwardly in an annular Space surrounding the well casing and reciprocal therein upon disconnection from the stationary body to permit access to the drill `string without a complete disassembly of the control head, means provided for Ilimiting the downward reciprocal movement of the said second sleeve, and seal means cooperating between the well casing and the reciprocal sleeve to preclude leakage of uid therebetween, and passageway means for discharge of iluid from the control head.

References Cited in the le of this patent UNITED STATES PATENTS 1,503,476 Childs et al Aug. 5, 1924 2,199,733 Beckman May 7, 1940 2,199,734 Beckman May 7, 1940 2,222,082 Leman et al Nov. 19, 1940 2,243,340 Hild May 27, 1941 2,475,429 Humason July 5, 1949 2,927,774 Ormsby Mar. 8, 1960 3,052,300 Hampton Sept. 4, 1962

Claims

2. A ROTARY CONTROL HEAD FOR A DRILL STRING AND COMPRISING A STATIONARY BODY MEMBER, A ROTATABLE SLEEVE DISPOSED AROUND THE DRILL STRING AND EXTENDING INTO THE BODY MEMBER, STATIC SEAL MEANS INTERPOSED BETWEEN THE SLEEVE AND THE DRILL STRING, DYNAMIC SEAL MEANS INTERPOSED BETWEEN THE STATIONARY BODY AND THE ROTATABLE SLEEVE, PASSAGEWAY MEANS FOR DISCHARGE OF FLUID FROM THE CONTROL HEAD, A PAIR OF CONCENTRIC ANNULAR COLLARS HAVING AN ANNULAR SPACE THEREBETWEEN AND SPACED FROM THE STATIONARY BODY, A SLEEVE MEMBE REMOVABLY SECURED TO THE LOWER END OF THE STATIONARY BODY AND RECIPROCALLY DISPOSED WITHIN THE ANNULAR SPACE TO PROVIDE FOR ACCESS TO THE DRILL STRING WITHOUT A COMPLETE DISASSEMBLY OF THE CONTROL HEAD, MEANS PROVIDED FOR LIMITING THE DOWNWARD RECIPROCAL MOVEMENT OF THE REMOVABLE SLEEVE, ADN SEAL MEANS PRECLUDING LEAKAGE OF FLUID BETWEEN THE COLLARS AND THE REMOVABLE SLEEVE.