US2590512A

US2590512A - Oil well swivel

Info

Publication number: US2590512A
Application number: US682023A
Authority: US
Inventors: Robert L Crain
Original assignee: Gray Tool Co
Current assignee: Vetco Gray LLC
Priority date: 1946-07-08
Filing date: 1946-07-08
Publication date: 1952-03-25
Anticipated expiration: 1969-03-25

Description

25 1952 R. L. GRAIN 9 OIL. WELL SWIVEL Filed July 8, 1946 2 Sl-lEETS-SHEET l Patented Mar. 25, 1952 OIL WELL SWIVEL Robert L. Grain, Houston, Tex., assignor to Gray Tool Company, Houston, Tex., a corporation of Texas Application July 8, 1946, Serial No. 682,023

2 Claims.

The present invention relates to oil well swivels, andisparticularly concerned with such a "swivel having improved means for yieldingly connecting the swivel tube into the'body of the swivel, so that the strains and bending stresses imposed on the former incident to rotary drilling operations will be yieldingly accommodated by the structure without unduewear of the parts and resulting leakage of the high pressure fluid which is passed through the swivel tube.

Thepresent invention relates to a swivel of the general type disclosed in Patent No. 1,746,036 to Gray, February 4, 1930,-which discloses a swivel provided with a body adapted to be suspended in the derrick and with a'swivel tube mounted in the body and extending below the same for attachment to the Kelley joint of the rotary drilling string, there being races of metal bearings provided in the'mounting of the swivel tube in the. body to take up vertical and side thrusts which are incident to rotary drilling operations. In the Gray patent, one manner of sealing the swivel tube with that part'of thebody'where connection is made with the conventional flexible mud hose is disclosed, but this construction has not been found to be entirely satisfactory in accommodating itself to the bending strains imposed on the swivel tube, and hence uneven wear of packing and uneven strains on other working parts and connections has resulted. understood that the swivel, while being supported from wire lines in the derrick, is so heavy (approximately one and one half tons in weight) that it will not follow all movements of the drill pipe .and thus of theswivel tube, and thus there are relative bending movements between the swivel tube and theswivel. body. In Patent No. 2,027,653,. Roye, January 14, 1936, an improved type of swivel and packing connection is disclosed,- but the arrangement of this patent has certain disadvantages which will be hereinafter apparent, the present invention being a further improvement over the-constructions disclosed in said patents.

A principal object of the present invention is to provide a swivel construction wherein the swivel tube is connected into the body of the swivel in such manner as to accommodate the various bending strains imposed on said tube incident to rotary drilling operations.

Specifically, it is a purpose of the invention to provide a connection between the rotating swivel tube and a non-rotating tubular portion of the swivel. body leading to a closed chamber in the body connected with the source of iluid under It will be pressure, which will permit various bending movements of the swivel tube resulting from .rotary drilling without undue strain on the connecting parts and on the rotary bearing surface which is customarily found in the swivel body adjacent the upper end of the swivel tube. More particularly,- we have provided a construction including a rotary bearing housingpositionedbetween the rotating and non-rotating parts which is capable of limited bending movements in 'response to bending strains imposed on theswivel tube from-the rotary-drill string.

A further object of the invention is to provide a construction of the general type referredto above, wherein the swivel tube terminates atits upper end in an upwardly extending wash pipe, which wash pipe is yieldably supported for bending-movements at its lower end on the upper end of the swivel tube, and further, to provide such wash pipe with a mountingadjacent its upper end: in the swivel body which is also capable of limited bending movements, wherebythe wash pipe is capable of limitedbending movements at both its lower and upper ends.

In connection with the above. one of the principal advantages of the invention is to provide, a rotary bearing mounted in the'body of the swivel comprising a housing containing packing which engages a rotating part extending from the swivel tube, which housing is capable of various bending movements so that its bore is constantly main-' tained in alignment with the upper end of the part extending from the swivel tube even though the latter is displaced from normal vertical by the bending strains of rotary drilling.

While one particular arrangement of the connections and packing is disclosed in the drawings, it will be understood that various modifications of the arrangements shown may be made, such as in the nature of reversal of certain of the parts. without departing from the scope of the invention.

In the drawings:

Figure 1 is a side elevational view of the top part of a swivel, for instance, a swivel of-the general type disclosed in said prior patents'the view being partially in section in order to illustrate the manner in which the upper end of the swivel tube (and the wash pipe which forms-a part thereof) is mounted in the swivel body.

Figure 2 is a horizontal sectional view through the upper bearing, taken along the line 22 of Figure 1.

Figure 3 is a horizontal sectional viewthrough the lower flexible connection betweenthe swivel 3 tube and the wash pipe, taken along the line 3--3 of Figure 1.

Figure 4 is a partial side elevational view of the general type of swivel of the present invention, showing the manner in which same is equipped for suspension in the derrick.

Figure 5 is a View similar to Figure 1 of a modified form of the invention.

In Figures 1 and 4, the swivel body is shown at B. It is adapted to be supported from the travelling block and hook of the derrick rig by means of a bail L, the bail carrying the weight of the entire swivel through vertically extending heavy bolts having heads l2 to which the lower ends of the bail are pivotally connected, all in the manner disclosed in said prior patents, particularly Patent 1,746,036 to Gray.

Rigidly and centrally connected to the upper end of the body and formin an integral extending part thereof, is a cage-like open bracket [4 having a top horizontal integral plate [6 with a vertical tubular passage l8 therethrough to receive and support the rotating upper end of a swivel tube S, or particularly, the upper extension of said tube shown in the form of a wash pipe W.

Mounted on the upper end of the body (specifically on the upper end of the bracket I4 thereof), is a goose-neck G which has a bolted flanged connection with the top of the bracket M in such manner as to provide a closed chamber C within the goose-neck through which the mud fluid is pumped under pressure and enters the upper end of the wash pipe W, thence passing downwardly into the swivel tube S. It will be understood that through a conventional bent side inlet 22 of the goose-neck and by means of ai-flexible hose attached thereto in a manner well known in the art, mud fluid is pumped into the swivel tube, flowing downwardly through the drill string and outwardly through openings at the lower end thereof adjacent the rotary drilling bit. The swivel tube S has conventional means at its lower end (below the body of the swivel),

such as a conventional tool joint, for connection with the drill string (specifically, the Kelley joint thereof) so that the swivel tube turns in the swivel body with the turning of the drill string which extends downwardly into the well, the drill string having rotation imparted thereto where its Kelley joint passes through the power driven rotary table on the derrick floor. As a result of the above, it will be seen that the swivel constitutes a relatively stable element suspended in the derrick, and which supports the drill string from the'derrick through suitable thrust bearings around the swivel tube and within the swivel body (not shown but which will be apparent from consideration of the Gray Patent 1,746,036), and the swivel must permit rotation therein of the swivel tube and at the same time provide a suitable connection with said rotating tube so that fluid under pressure may be pumped into the drill string through the goose-neck and its chamber C, the latter being a relatively fixed part as compared with the rotatin swivel tube itself.

*It is well known to those skilled in the art that rotary drilling and allied operations are rugged in nature, as the bit is caused to successively penetrate relatively soft sands as well as relatively hard rock formations. As a result of this, and when the great length and weight of the drill string is considered, it will be apparent that many bending stresses and strains on the swivel tube take place. Thesemustbe accommodated within the swivel body and by the connections therein as now to be described, without excessive wear on the working parts and connections which would require repair of the swivel at too frequent intervals, or which would perhaps result in leakage in the swivel at a critical stage in the drilling of the well. It is well known that the presence of the heavy mud fluid immediately available to be pumped into the well is essential at critical periods during drilling and allied operations to resist the high formation pressures which might cause a blow-out if the parts are not in perfect operating condition.

As'stated above, the swivel tube S is equipped with suitable vertical and side thrust bearings (as shown in the Gray Patent 1,746,036) below that portion of the tube which is shown in Figure 1, and the upper end of the tube extends above the closed body of the swivel into the opening between the legs of the bracket 14. The upper end ofthe swivel tube proper is provided with an internal counterbore or packing recess 26, open at the upper end of the tube, and in this bore there are a number of packing rings 28 of any suitable type, such as hard rubber or the like. The lower end of the wash pipe W (which constitutes a continuation of the swivel tube) is provided with an outwardly extending circular boss 30 comprising side outwardly slanting portions 32 with a central straight portion between the same, or the boss 30 may be generally outwardly rounded in-form. The boss 30 is of such diameter as to extend into the counter bore 26 in the upper end of the swivel tube as previously described. The sealing rings 28 may be packed into the groove 26 around the boss 30 as shown, and when the parts have been thus assembled, a packing compressing follower ring 36 is inserted downwardly into the cavity engaging the outer-most packing ring 28. This follower is pressed downwardly to compress the packing 28 against the side and bottom walls of the cavity 26 and againstthe upper, lower and central walls of the boss by a circular nut 38 threaded onto the outer end of the swivel tube S and which has a flange bearing against the outer surface of the follower 36. The nut 38 is threaded onto the swivel tube to a sufficient degree to insure tightness of the packing 28 in its recess 26 as previously described so that a fluid pressure-tight joint results.

On the other hand, the joint is not so tight as to prevent bending movements in any direction of the wash pipe W with respect to the swivel tube, or stated in another way, such movements of the swivel tube with respect to the wash pipe. It will be evident that the joint remains tight even though the strains of rotary drilling cause some misalignment of the swivel tube S with respect to the wash pipe W, the opening through the follower 36 and through the nut 38 being somewhat greater than the outer diameter of the wash pipe W above the boss 30 permitting relative bending movements of the wash pipe. Due to the construction of the boss 30 these bending movements will not reduce the pressure on the packing 28, in fact, any given bending movement will cause an increase of pressure on the packing at certain circular areas in order to insure the tightness of the seal.

While the tightness of the packing 28 may be depended on to insure turning movement of the washpipei'Vv with the swivel tube S, locking screws may be threaded through the side wall of the swivel tube and into dished-out ,or beveled grooves 42 in the outer face of the central portion of the boss 30, in order to keythewash pipe to the swivel tube to insure that these two members rotate in unison, while permitting the bending movements referred to above.

'Where the upper end of the wash pipe extends through the tubular opening IS in the top plate l6 iOf"l'/h bracket 14 and into the chamber C,

alswivel tube or wash pipe bearing housing H is'mounted for limited pivotal movement. This bearing housing is of generally sleeve-like form, having a bore 44 extending centrally therethrough, the upper end of the bore being closed by a shoulder 46 against which an interior end packing retaining ring 48 is engaged as shown in Figure 1. 'Within the bore 44, a plurality of rotary packing elements are provided, same comprising annular impregnated fabric packing rings 50 of U-shaped cross-section separated from one another by T-shaped brass spacing elements 52, the open edges of the packing elements 50 being presented toward the source of pressure, (i. e., the chamber C) so that pressure of fluid exerted downwardly through the bore 44 of the housing H tends to expand the packing rings against the bore 44 and the outer wall of the wash pipe W. The packing elements just mentioned are retained in the bore 44 by a follower 56 which enters the lower end of said bore around the wash pipe W, same being forced upwardly into the bore to properly compress the packing by a circular nut 58 which is threaded onto the lower outside end of the housing H in the manner shown in Figure 1. The bottom opening through the nut 58, the retaining ring 48 and the follower 56 embrace the wash pipe to insure that the housing H will bend with the wash pipe as hereinafter described.

With this construction, it will be apparent that the swivel tube and its extending wash pipe may rotate in the body of the swivel during the drilling operations, and the packing within the housing H will maintain a tight seal around the rotating parts to confine the pressure fluid which enters at 22 or any back pressure from the well tothe chamber C and the interior of the wash pipe W and the swivel tube S. In the case of back pressure, it will be understood that the same is resisted by stepping up the pressure from the mud pumps and thus increasing the pressure of fluid entering the chamber C from the inlet 22.

With respect to the rotary packing just described, it will be understood that even wear thereon is of great importance during such rugged operations as are involved in drilling a well, for misalignment of the swivel tube S (or its wash pipe W) with respect to the rotary packing in the housing H would cause uneven wear on such packing with inevitable leakage. The importance of the limited bending joint at the lower end of the wash pipe, as just described, will therefore be apparent.

In addition, I have provided for limited bending movement at the upper end of the swivel tube (or its wash pipe W) with respect to the body of the swivel at the point where the bearing housing H is mounted. The tubular opening [8 through the upper end of the swivel body is counter bored as at 60 in order to receive several packing rings 62 of the type previously described, and the outer wall of the'housing H is provided with a boss 64 similar in form to the boss 36 on the lower end of the wash pipe W but of some what larger size, as shown. The boss 64 is centrally positioned in the counterbolie 16, and the packing is properly tightened in "said bore by a downwardly extending flange 66-whichacts as a packing follower upon entering the counterbore when bolts 68 extending through the flange 20 of the goose-neck G are tightened, the resulting action serving to seal the chamber C and at the same time tighten the packing around the boss 64. It will be noted that the outer diameter of the upper end of the housing His somewhat less than the interior diameter of the chamber C of the goose-neck G,rso thatas previously described, the housing'I-I may bend in any direction to a limited extent inorder to continuously maintain alignment with the wash pipe W, even though the latter maybe misaligned in any direction to a limited extent with respect to the swivel tube S. As previously mentioned the arrangement of the packing 62 is such that its seal will not be impaired by shifting or bending movements of the housing H, in fact, bending movements will cause a tightening of said packing throughout various circular zones or areas due to pressure exerted by the boss 64.

From the above, it will be apparent that I have provided an improved seal for the rotating swivel tube within the body of the relatively fixed swivel, and that various strains and bending movements incident to rotary drilling may be yieldingly accommodated. The swivel tube S may shift from aligned relation with respect to the wash pipe W, and the latter may in turn shift from exact alignment with the tubular passage 18 through the upper end of the swivel body. At the same time, it will be evident that the housing H can move with the wash pipe W and retain itself in alignment therewith so that no uneven wear on the rotary packing can result. Due to the above construction, replacement of the wearing or connecting'parts only need beperformed at infrequent intervals, and there is no possibility of leakage developing at a critical time in the drilling of a well. It will be understood that the latter contingency is of extreme gravity, for swivels cannot usually be repaired while attached in working position at the well, and a replacement swivel is not always readily available, these devices being an expensive item in well equipment.

While we have shown a preferred arrangement of the general elements described, it will be understood that the invention is susceptible of somewhat wide variations in the relative arrangement of the parts. For example, it-would be possible to reverse the parts shown in Figure 1 so that the wash pipe W is fixed for bending movement only in the opening through the upper end of the bracket 14, the housing H being carried for bending movement in the open upper end of the swivel tube S. In such a modification, the rotary packing carried by the housing H would rotate with the swivel tube S and around the lower end of the wash pipe W, there being, as in the preferred embodiment, permissable bending movements at the lower and upper ends of the wash pipe as previously described. Other variations will be apparent to those skilled in the art.

Figure 5 discloses a variation of the type mentioned in the preceding paragraph. This view, which is generally similar to Figure 1, shows the body of the swivel at B with the "bracket I05 with its top plate 164 integrally connected with the body and extending abovethe same" as'previ ously described. The swivel tube S is mounted in the swivel body in the same manner as previously described, extending upwardly and terminating within the open part of the bracket I06. A modified type of goose neck G is shown connected to the top plate I04 of the bracket I06. A Wash pipe W (which is a continuation of the swivel tube S is shown connected between the body of the swivel (or the goose neck connection) and the upper end of the swivel tube. The connection between the wash pipe and the swivel tube is by means of a bearing housing H of the same general type as previously described.

The lower end of the bearing housing H has an outside circular boss or enlargement I0, with the tapering surfaces I2 as previously referred to. This boss forms part of a flexible bending joint connection with the top of the swivel tube, there being appropriate packing rings I4 in the counterbore I6 in the upper end of the swivel tube, which rings engage the tapered surfaces I2 of the boss I0, the packing being tightened in the counterbore by a nut I8 threaded exteriorly onto the end of the swivel tube, and having a top flange which engages and compresses the packing I4 as shown. As has been described in connection with the embodiment of Figure 1, the center opening through the top of the nut I8 is large enough to permit the limited bending movements of the swivel tube with respect to the bearing housing, or stated another way, to permit the bearing housing to maintain alignment with wash pipe W irrespective of the position of the swivel tube or the wash pipe. The upwardly extending cylindrical portion 80 of the bearing housing has a counterbore 82, and in this counterbore, there is packing 84 of the type previously described. This packing is maintained in tight condition against the outer wall of the wash pipe by a circular follower 86 which is pressed downwardly into the counterbore 82 by a nut 88 threaded exteriorly on the upper end of the extension 80, and having a top flange which engages the follower 86. As shown, the lower end of the wash pipe passes downwardly through the packing 82 and terminates at a point below said packing.

The upper end of the wash pipe W has an exterior circular boss 92 substantially identical with the boss 30 described in connection with Figure 1. The lower slanting surface 96 of this boss engages packing in a circular counterbore I in the center of the top plate I04. The upper tapered surface of the boss 92 extends beyond the top plate I04 and is engaged by similar packing 94 in a counterbore 98 in the lower end of the goose neck G the horizontal ledge 98 of the counterbore serving as a circular abutment to press the packing 94 downwardly across the upper slanting surface of the boss 92, and to also press the lower slanting surface of said boss against the packing in the counterbore I00. The goose neck G has a passage 0 which forms a chamber for the inflow of mud into the wash pipe, thence to the swivel tube, and then to the drilling string. It will be noted that the opening through the top plate I04 for the wash pipe is suiliciently large to permit bending of the wash pipe with respect to the body of the swivel.

With this arrangement, the swivel tube S may turn during the drilling or other operations, and when stresses are encountered, limited bending movement between said tube and the wash pipe at the upper end of the swivel tube is permitted by means-of the flexible joint including the circular boss 10. Corresponding or resulting bending movements are permitted between the upper end of the wash pipe and the body of the swivel (or the goose neck), by means of the flexible joint comprising in part the circular boss 92. The bearing housing H will rotate with the swivel tube, and the seal around the lower end of the wash pipe is effected by the rotary bearing carried by the bearing housing H and including the packing 82'. Bending movements of the bearing housing H are provided for, so that said housing constantly maintains itself in alignment with the wash pipe W in spite of misalignments of the swivel tube with the wash pipe, so that there is no uneven wear on the bearings 82. While the tightness of the flexible joint at the upper end of the swivel tube S may be relied on to insure rotation of the bearing housing H with the swivel tube, suitable connecting means similar to the screws 40, as shown in Figure 1, may be provided for this purpose as desired.

I claim:

1. In an oil well swivel, a body having means for suspending same in the derrick, a swivel tube extending upwardly into said body, said body having means for supporting said tube for rotation therein, said tube having means adjacent its lower end for connection with the rotary drilling string and being thereby subject to the bending movements incident to rotary drilling operations, said body having an enclosure at its upper end which forms a closed chamber for conveying fluid into said tube and into said drilling string, a wash pipe connected between the upper ends of said tube and body to form a fluid connection between said chamber and said tube, means joining and sealing the lower end of said pipe with the upper end of said tube while providing for limited and universal misalignment of said pipe during rotary drilling operations, and a sealed driving connection between the lower end of said pipe and the upper end of said tube providing for the rotation of said pipe with said tube and for limited and universal misalignment of said pipe during rotary drilling operations, said connection including a packing chamber on said tube to receive the lower end of said pipe and loosely interfitting radially presented key members and grooves on said tube and said pipe, and a quantity of yieldable packing compressed in said packing chamber between said pipe and said tube,

2. In an oil well swivel, a body having means for suspending same in the derrick, a swivel tube extending upwardly into said body, said body having means for supporting said tube for rotation therein, said tube having means adjacent its lower end for connection with the rotary drilling string and being thereby subject to the bending movements incident to rotary drilling operations, said body having an enclosure at its upper end which forms a closed chamber for conveying fluid into said tube and into said drilling string, a wash pipe connected between the upper ends of said tube and body to form a fluid connection between said chamber and said tube, means joining and sealing the lower end of said pipe with the upper-end of said tube while providing for limited and universal misalignment of said pipe during rotary drilling operations, and a sealed driving connection between the lower end of said pipe and the upper end of said tube providing for the rotation of said pipe with said tube and for limited and universal misalignment of said pipe during rotary drilling operations, said connection including an annular packing chamber in the upper end of said tube of diameter great enough to receive the lower end of said pipe therein with an annular intervening clearance space, loosely interfitting radially presented key members and grooveson said tube and said pipe, 5 a quantity of yieldable packing material in said packing chamber and a retaining ring therefor on said tube, said ring having an enlarged inside diameter providing clearance space around said pipe for the universal misalignment of the latter 0 during rotary drilling operations.

ROBERT L. 'CRAIN.

REFERENCES CITED The following references are of record in the 15 file of this patent:

UNITED STATES PATENTS Number Name Date Morgan Nov. 3, 1931 Ruot Apr. 12, 1932 Banks Jan. 17, 1933 Spalding Feb. 18, 1936 Shaw et a1 Apr. 8, 1941 Murphy Feb. 12, 1946 Tremolada Jan. 18, 1949 Tremolada May 24, 1949 Tremolada Oct. 25, 1949 Tremolada Nov. 15, 1949 Tremolada Feb. 7, 1950