US2973996A - Stabilizer for drill pipe - Google Patents

Description

March 7, 1961 E. s. SELF 2,973,996

STABILIZER FOR DRILL PIPE -4 sheet-sheet 1 Filed Jan. 9, 1957 l I I 52 INVENTOR. .Ebnmeo SAW/4 522;

March 7, 1961 E. s. SELF STABILIZER FOR DRILL PIPE 4 Sheets-Sheet 2 Filed Jan. 9, 1957 INVENTOR. 12W Sana/:4 .522;

March 7, 1961 Filed Jan. 9, 1957 E. S. SELF STABILIZER FOR DRILL PIPE 4 Sheets-Sheet 5 INVENTOR. .Zowaea 54/1405; 5:4;

March 7, 1961 E. s. SELF I STABILIZER FOR DRILL PIPE 4 Sheets-Sheet 4 Filed Jan. 9, 1957 lbw/zen 5444054 .522

INVENTOR.

U ited States am STABILIZER FOR DRILL PIPE Edward Samuel Sell, Ventura, Calif. (1315 Gravier St., New Orleans 12, La.)

Filed Jan. 9, 1957, Ser. No. 633,355

17 Claims. (Cl. 308-4) 7 This invention relates to anti-friction devices for use in bore holes, and more particularly to a stabilizer for use on tubing of various types and especially on drill pipe to prevent substantial transverse movement of the pipe within a well without interfering with its normally free rotational and longitudinal movement.

It is, of course, obvious that a drill pipe in a rotary drilling rig must be kept free to'rotate and to be lowered into or removed from awell. However, it is desirable to prevent substantial transverse movement of the pipe in the well and especially during drilling operations because whipping of tool joints in a string of drill pipe causes wear on internal casing walls and sometimes causes either a tool joint or the casing to become badly damaged.

In addition to these problems, not only the whipping but also the rotational movement of drill pipe causes recesses known as key seats to be formed around the tool joints of the pipe in the earthen bore of a well. This means that a tool joint of the drill pipe may become fixed or stuck at a key seat and considerable time, expense, and difficulty may be encountered in recovering the drill pipe from the well.

Several devices of the prior art have been employed to overcome these difliculties. A typical one includes a pair of races to house ball or roller bearings, means to fix the races around a drill pipe in a spaced relation ship along it, and means fixed to the outer rotatable rings of the races to maintain the pipe spaced from the well bore and to locate the pipe substantially centrally thereof.

Such a device does prevent the drill pipe from whipping and maintains it in a rotatable angular and movable axial position. However, the ball or roller bearings em ployed therein wear extremely fast and are diflicult to seal off from sand flowing upwardly in a well with drilling fluid that is circulated in that direction. The sand causes these bearings to become pitted and thereby shortens the life of such devices to a considerable extent.

The present invention overcomes these and other disadvantages of the prior art by providing a stabilizer for drill pipe which may have tool joints along its length, the stabilizer being constructed for use in a well upwardly in which a drilling fluid is circulated, this being the normal case. Accordingly, this stabilizer includes means surrounding the bearing mounted rotatably with respect to the pipe to prevent substantial transverse movement of the pipe in the well, and fixed means for limiting the axial movement of both the spacing means and the bearing along the pipe without limiting the rotational movement of the spacing means and the bearing therearound. According to the invention, the use of hard rubber in the bearing preferably molded as a solid cylinder and drilled out has several advantages. Inthe first place, it is not worn by sand abrasion as badly as metal because of its resilient character even in spite of the fact that it is a rather soft material as compared to the metal material of a ball or roller bearing. In addition, hard rubber wears well even in the presence of oil base drilling muds and has a high shock resistance. Furthermore, oil

ice,

, 2 and water base muds effectively lubricate hard rubberso that it acts as a low friction bearing in the presence of these types of circulation fluids which are used in drilling operations.

According to a feature of the invention, the spacer means preferably is provided with longitudinal ribs to engage the well bore, the ribs defining passages between them enabling circulation of drilling fluid upwardly in the well past" the stabilizer of the invention. The ribs are also preferably tapered at each end to facilitate lowering and raising of the drill pipe into and out of the well without becoming fixed or stuck therein.

According to another feature of the invention, the hard rubber bearing is split throughout its length, whereby it may be easily mounted in position around the drill pipe, and the spacer means is a solid cylindrical body having the ribs connected to its external surface and having an inside diameter greater than the outside diameter of the tool joints of the drill pipe, whereby it may be e'asiljy located at any position along the drill pipe.

According to a specific embodiment of the invention, the ribs are made straight and wear skids are additionally provided at the radial extremities of the ribs, the skids being removable. In this case, the skids may be replaced if they become worn.

According to another aspect of the invention, the wear skids are made of a hard material in comparison to, for example, aluminum, and a cylindrical body is made of a soft material in comparison to steel, such as, for example, hard rubber or aluminum. The skids are then attached to the ribs at a radial distance from the hard rubber bearing to permit their severance by milling the cylindrical body in the space between the bearing and the skids. According to this method, washove'r pipe may be easily lowered over the milled body to move material away from the drill pipe farther down in the well, i.e. below the stabilizer, to free the drill pipeif it becomes stuck.

The invention also contemplates the use of meansfixed to the drill pipe both above and below the bearing and cylindrical body, respectively, to maintain the bearing and cylindrical body in a substantially fixed longitudinal position on the drill pipe. In one case, the hard rubber bearing is provided with' an outwardly or a radially directed flange at its upper end to fit between the upperend of the cylindrical body and the upper member fixed to the drill pipe. The pressure of upwardly circulating drilling fluid will generally force the cylindrical body against the radial projection of the hard rubber bearing andthe 7 projection, in turn, against the upper member fixed to the drill pipe. Hence,- the projection also serves as a thrust bearing for the stabilizer of the invention. H a

In accordance with another embodiment of the inven tion, each of the members fixed to the drill pipe to limit the longitudinal movement of tliebearing and cylindrical body thereon are made in the form of clamps toembrace clamps are prefthe circumference of the'drill pipe. The erably split and, hence, easy to fix to' the drill pipe.

Another feature of the invention involves the use of a lower member having first dog means fixed to its upper end extending upwardly toward the cylindrical body. In

this case, the cylindrical body is also provided with sec ond dog means to engage the first dog means, each of the dog means being constructed to" limit the rotational movement of a cylindrical body with respect to the drill pipe-to one direction whenthe second dog means engages the first dog means. By the use of the dog means, the

cylindrical body may be more easily milled away in the event the drill pipe-becomes stuck at a depth below the? stabilizer, the stabilizer being fixed in engagement .of the dog means. v

Still another feature of the invention ineludesthe use position by the of a hard rubber bearing having a length greater than the cylindrical body and extending below it to engage the first dog means before the second dog means engage them. In this case, the cylindrical body is protected against shock loads as the drill pipe is removed from the well.

Another structure for removing a hard rubber cylindrical body might include knife edges on the lower mem ber fixed to the drill pipe to mill the bottom surface of both the hard rubber bearing and hard rubber cylindrical body in response to the rotational movement of the knife edges.

In the operation of the stabilizer of the invention, the drill pipe may become worn. The stabilizer is easily moved from one place to another along the drill pipe and may, in fact, be moved to avoid any substantial wear on the drill pipe. However, a replaceable sleeve of a sheet material may be fixed to the pipe by the two clamps, the sleeve being positioned between the hard rubber bearing and the drill pipe and being maintained in a fixed position on the drill pipe by the clamps. In this manner, any wear of the drill pipe may be substantially prevented. Hard anodized aluminum is preferably used for the sleeve because of its unusually good wear resistant oxide coating.

It is, therefore, an object of the invention to provide an extremely wear-resistant pipe stabilizer for use in a Well bore.

It is another object of the invention to provide a pipe stabilizer having relatively few inexpensive, replaceable component parts.

Still another object of the invention is to provide a stabilizer which may be easily mounted on drill pipe.

A further object of the invention is to provide a drill pipe stabilizer which may be easily cut away and removed from interference with washover pipe which may be lowered over it when the drill pipe becomes stuck in a well before the position of the stabilizer.

A still further object of the invention is to provide a pipe stabilizer which may be easily lowered into and recovered from a well.

The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages thereof, will be better understood from the following description considered in connection with the accompanying drawings. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the invention.

Fig. 1 is a side elevational view of two of the stabilizers of the present invention shown on a string of drill pipe;

Fig. 2 is a longitudinal sectional view of one of the stabilizers shown in Fig. 1 taken on the line 2--2;

Fig. 3 is a section on the line 3-3 of the stabilizer shown in Fig. 2;

Fig. 4 is an exploded view of two of the elements shown in the stabilizer of Fig. 2;

Fig. 5 is a broken-away longitudinal sectional view of a steel sleeve mounted on a drill pipe in accordance with another embodiment of the invention;

Fig. 6 is a sectional view of the sleeve of the assembly taken on the line 6-6 and shown in Fig.5;

Fig. 7 is a perspective view of a bearing housing constructed in accordance with still another embodiment of the invention;

Fig. 8 is a sectional view of the housing taken on the line 8-8 shown in Fig. 7;

Fig. 9 is a longitudinal sectional view of a stabilizer having an alternative construction;

Fig. 10 is a transverse sectional view of the stabilizer shown in Fig. 9 and taken on the line 10-10 shown therein;

Fig. 11 is a longitudinal sectional view of still another embodiment of the invention; and

Fig. 12 is a transverse sectional view taken on the line 12-12 shown in Fig. 11.

In the drawing in Fig. 1 a pair of drill pipe stabilizers 10 and 12 are shown mounted on a string of drill pipe 14 on opposite sides of a tool joint 16. The stabilizers 10 and 12 are mounted in rotatable angular, but substantially fixed, axial positions on the pipe 14. For example, stabilizer 10 includes a hard rubber bearing 18 which is disposed inside a bearing housing 20. The bearing 18 is preferably made from a molded, solid, cylindrical hard rubber body. This improves its wear characteristics considerably. The longitudinal movement up and down along the pipe 14 of housing 20 is limited, respectively, by upper and lower clamps 22 and 24, respectively. Each of the clamps 22 and 24 are provided with means 26 to grip the pipe 14. Clamp 22 is fixed to the pipe 14 by means of radially extending and facing flanges 28 through which bolt and nut assemblies 30 are fixed.

Clamps 22 and 24 are positioned above and below drill pipe stabilizer 10 such that it will not move longitudinally along the pipe. Clamp 22 is provided with a circumferential flange 32 to engage a radially extending projection 34 at its upper end of bearing 18. A hard rubber thrust bearing 34 is then disposed between the flange 32 and the upper end of housing 20.

Housing 20 includes a six pointed star-shaped body portion 38 as best illustrated in Fig. 3 having longitudinal ribs 40. The ribs 40 are provided with fluted assageways 42 in which skid members 44 are positioned. The skid members are fixed to the ribs 40 by means of bolts 46.

At the lower end of housing 20, dogs 48 are provided to engage dogs 50 which extend upwardly and form an i tegral part of the clamp 24. Clamp 24 is similarly provided with longitudinal flanges 52 which are fixed together by a bolt and nut assembly 54. The dogs 50 then form an integral part of the clamp 24 as an integral part of a radially extending flange 56 similar to the fl nge 32 of the clamp 22. The working mechanism of the dogs 48, 50 will be explained in detail hereinafter.

When the drill pipe 14 is withdrawn from a well, the dogs 48 and 5t) tend to engage each other and damage each other as the housing 20 moves upwardly and down- Hardly between the clamps 22 and 24. For this reason, a hard rubber ring 58 preferably is positioned between dogs 48 and dogs 50.

An exploded view of clamp 22 and bearing 18 is shown in Fig. 4 to better illustrate their respective functions.

As stated previously, the use of a molded hard rubber in the bearing 18 has several advantages. In the first place, it is not worn by sand abrasion; secondly, it Wears well even in the presence of oil base drilling muds, and oil and water base muds further effectively lubricate hard rubber so that it acts as a low friction bearing in the presence of these types of circulation fluids used in drilling operations.

The ribs 40 are preferably tapered at each end as shown in Fig. 2 to prevent their upper and lower ends from being caught by uneven sections in a bore hole.

The bearing 18 need not be solid but may be split to make it easy to mount the stabilizer on pipe 14. Although housing 20 may also be split, not shown, it is preferably made of a solid extruded body of, for example, aluminum. In this case, the inside diameter of the housing 20 is preferably made larger than the outside diameter of the tool joint 16 so that it may easily be moved to any position along a string of drill pipe.

It is to be noted that the ribs 40 are spaced apart and define passages enabling circulation of drilling fluid upwardly in the well past the stabilizer 10.

The manner in which the skids 44 are mounted on the ribs 40 means that the skids 44 may be made of a soft material relative to steel, such as, for example, aluseas-pas r'n'inum. in addition, housing 2i may be made of aluminurn, whereby the housing 20 may be milled to permit the lowering of a washover pipe over it, milling being accomplished in the space between the bearing 13 and the inner sides of the skid-s 44. Furthermore, the skids 44 may easily be replaced if they become worn. The skids are easily mounted upon ribs 40'. Likewise, the whole stabilizer is easily mounted on drill pipe 14. As stated previously, the stabilizer 10 may easily be moved upwardly and downwardly along drill pipe 14 simply by removing bolt and nut assemblies 30 to loosen clamps 22 and 24 when bearing 18 is split.

Dog means '48 and 50 are designed to cooperate with each other to prevent movement of housing 20 in the clockwise direction as viewed in Fig. 3. Generally a milling head on the end of washover pipe will move in this direction to mill the ribs 4t} oiif of the housing 2%. I t will be apparent that rubber ring 53 will be demolished in this case.

Alternatively, the housing 2% may also be made of hard rubber. In this case, dogs 48 need not be provided. Dogs 50 are then preferably provided with sharp edges to mill the rubber away as the housing 20 is also milled away at its upper end.

it has been found that when clamps 22 and 24 are made of a magnesium and bronze alloy, they provide adequate strength with a minimum weight. Housing 2%) may be made of an alloy of 90 percent aluminum and 10 percent magnesium.

Drilling mud pressure will generally keep dogs 43 spaced from dogs 50. Accordingly, as clamp 22 rotates with drill pipe 14, the projection 34 on hearing 18 will provide a low friction bearing surface as the housing 29 tends to move up into engagement with flange 32 of clamp 22.

Alternative, bumpers, which constitute hollow rubber cylinders of an inside diameter somewhat less than that of the drill pipe 14, may be mounted on the drill pipe 14 at the positions of clamps 22 and 24 to serve as means to limit the axial movement of housing 20 and bearing 18 on drill pipe 14. It is to be noted further that bearing 18 may be connected to housing 20 if desired.

In Figs. 5 and 6, a sleeve 68, which is preferably made of hard anodized aluminum, is shown having a longitudinal slit 70. Normal processes create an oxide coating thickness on aluminum of about 0.0001 to 0.0008 inch. However, sleeve 68 is preferably made of aluminum having an oxide coating thickness from 0.001 to 0.005. inch. This type of aluminum is called hard anodized? aluminum. Processes for making it are described in Hard Anodizing of Aluminum, Aluminum News, October 1955. See also New Aluminum Hard Surfacing Process Gives Hard Abrasion Resistant Coating, Western Metals, February 1954. Sleeve 68 is disposed about drill pipe 14 and may be fixed to drill pipe 14 by clamps 22 and 24 or equivalent means. Inthis case, a bearing 76 split at 36 is then disposed around sleeve 68 to prevent drill pipe 14 from wearing on its external surface at the position that stabilizer it} is mounted. Sleeve 68 is preferably split to permit it to be easily mounted around drill pipe 14.

Alternatively, a housing 60 as shown in Figs. 7 and 8 when a housing 116 disposed therearound remains stationary with respect to a well in which it is positioned as the drill pipe 14 and hence bearing 114 rotate together within the housing 116. Housing 116 is substantially identical with housing 20 shown in Fig. 2 except for the; fact that a shoulder is provided at 118 closing one end -of fluted channels 120 in ribs 122 of the housing 116.

The shoulders 118 are provided simply to prevent upward vertical movement of skids 124 in the channels 122. Skids 124 are locked in position in channels 120 by means of bolts 126 which may be threaded transversely through both skids 124 and the body of ribs 122.

Dog means 128 are provided on the lower end of housing 116 to engage dog'means 130* on the upper side of clamp 104-. A thrust bearing 132 is provided between the lower end of clamp 102 and the upper end of housing 116 and formed integrally with bearing 114 in a manner similarto the construction of thrust bearing 34 on bearing 18 shown in Fig. 2. A bumper 1'34 is also made integral with hearing 114 in a manner similar to V the manner in which free ring 58 is provided on pipe 14 in Fig. 2. from damaging dogs 130 when the stabilizer 100 is removed from a well. The manner in which the side walls of fluted channels 120 are inclined away from each other is illustrated in Fig. 10 where a sectional view of the stabilizer 100 is shown.

An alternative embodiment of the invention is shown in Fig. 11 including hard rubber bearing means 200 comprising roller bearings 201 which are positioned longitudinally of and in rolling contact with a drill pipe 14. The roller bearings 201 are cylindrical in shape and are located in recesses 202 and 203 in upper and lower roller bearing housings 204 and 205, respectively, which are fixed to the drill pipe 14 by means or upper and lower clamps 206 and 207, respectively, which may be similar to the clamps 102 and104 shown in Fig. 9.

Bearing means 200 also includes a hollow cylindrical body 208 and is located between spacer means 239 and the roller bearings 201 and maintained in rotatably angular but fixed axial positions between the upper and'lower are provided including upper and lower flanges 62 and 64 and spiral-shaped ribs '66.

A stabilizer 100 is shown in Fig. 9 fixed to drill pipe 14. The stabilizer 190 comprises upper and lower clamps 102 and 104 which are very similar to clamps 22and24 of the embodiment of the invention shown in Figs. 1 and 2, except for the fact that each of the clamps 102 and 104 are provided with counterbores 1&6 and 103, respectively, to receive upwardly and downwardly extending ends 110 and 112, respectively, of a split hard rubber bearing 114. In this manner, bearing 114 is clamped to drill pipe 14 to prevent wear on drill pipe 14 roller bearing housing 204, 205. Thus, body 203 which may be considered a roller bearing. race, may slide against the external surface of the roller bearings 201 or the internal surface of a housing 210 of spacer means 2119. Housing 210 includes a stop 211 at its upper end similar to a stop indicated at 118 in Fig. 9. Spacer means 209 is also provided with skid members 212, which are slidably disposed in grooves 213 in housing 210 and retained therein by means of bolt'and nut assemblies 214 better illustrated in Fig. 12. It isto be noted that upper and lower clamps 206 and 207 may be provided with lubricating holes 215. Thus, drilling mud may be employed to lubricate the whole spacer assembly shown in Fig. 12.

Alternatively, the bearing means 200 may be sealed on and grease may be packed into the roller bearings 201 to lubricate the drill pipe stabilizer.

As in the case of clamps 104, clamps 2%? in the lower end of housing 210 may be provided with interlocking dogs to engage each other when it is necessary to mill oif outer projecting ribs 216 of housing 210 formed by skids 212 in recesses 213.

It is to be noted further that the outer surfaces of skids 212 may also be conveniently covered with a hard rubber material 217. i

It is to be noted that the bearing surfaces of all the hard rubber bearings or hearing means included in all the embodiments of the invention may be impregnated with graphite to facilitate further lubrication thereof. This impregnation should be distinguished from the ordinary mixture of graphite with. latex to increase the stifihave been shown, it is to be understoodthat the invention is by no means limited to these embodiments, but that In this case, bumper 134 prevents dogs 128 the scope of the invention is defined only in the appended claims.

What is claimed is:

1. In a stabilizer for drill pipe having tool joints along its length, said stabilizer being constructed for use in a well in which drilling fluid is upwardly circulated, the combination'comprising: a hard rubber bearing to fit around the pipe; spacing means surrounding said bearing mounted rotatably with respect to said pipe to prevent substantial transverse movement of said pipe in the well, said spacing means being made of a relatively soft millable material; and upper and lower clamps fixed to said drill pipe respectively above and below said spacer means and said bearing for limiting axial movement of both said spacer means and said bearing along said pipe without limiting the rotational movement of said spacing means therearound, said lower clamp being provided with upwardly extending dog means having knife edges to mill the bottom surface of said spacing means and said bearing in response to their rotational movement on said knife edges.

2. In a stabilizer for drill pipe having tool joints along its length, said stabilizer being constructed for use in a well in which a drilling fluid is upwardly circulated, the combination comprising: a hard anodized sheet of aluminum to extend around said drill pipe; upper and lower clamps at the upper and lower ends of said sheet to hold said sheet against said drill pipe in a fixed position thereon; a hard rubber bearing to fit around said sheet between said clamps; and spacing means surrounding said hearing between said clamps, mounted rotatably with respect to said bearing to prevent substantial transverse movement of said pipe in the well, said clamps limiting the axial movement of both of said spacing means and said bearing along said pipe without limiting the rotational movement of said bearing and said spacing means therearound.

3. A drill pipe stabilizer comprising: spacing means rotatably mounted around the drill pipe, said spacing means being made of a relatively soft millable material; and upper and lower means above and below said spacing means, respectively, to limit longitudinal movement thereon on the drill pipe, said lower means extending around the drill pipe and having upwardly extending dog means with knife edges to mill the bottom surface of said spacing means in response to rotational movement of said spacing means on said knife edges.

4. In a stabilizer for drill pipe having tool joints along its length, said stabilizer being constructed for use in a well in which a drilling fluid is upwardly circulated, the combination comprising: a molded hard rubber bearing means to fit rotatably around the pipe, said bearing means being split throughout its length whereby it may be easily mounted in position around said pipe; spacer means surrounding said bearing means mounted rotatably with respect to said bearing means, said spacer means having longitudinal ribs to prevent substantial transverse movement of said drill pipe in the well, said ribs defining passageways between them enabling circulation of said drilling fluid upwardly in the well past said stabilizer, said spacer means being a solid cylindrical body having said ribs connected to its external surface and having an inside diameter greater than the outside diameter of the tool joints of said drill pipe, whereby it may be easily located at any position along said drill pipe; and fixed means for limiting the axial movement of both said spacer means and said bearing along said pipe without limiting the rotational movement of said bearing means and said spacer means therearound.

5. In a stabilizer for drill pipe having tool joints along its length, said stabilizer being constructed for use in a well in which a drilling fluid is upwardly circulated, the combination comprising: a molded hard rubber hearing means to fit rotatably around the pipe, said bearing means being split throughout its length whereby it may be easily mounted in position around said pipe; spacer means surrounding said bearing means mounted rotatably with respect to said bearing means, said spacer means having straight longitudinal ribs to prevent substantial transverse movement of said drill pipe in the well, said ribs defining passageways between them enabling circulation of said drilling fluid upwardly in the well past said stabilizer, said spacer means being a solid cylin drical body having said ribs connected to its external surface and having an inside diameter greater than the outside diameter of the tool joints of said drill pipe, whereby it may be easily located at any position along said drill pipe; fixed means for limiting the axial movement of both said spacer means and said bearing along said pipe without limiting the rotational movement of said bearing means and said spacer means therearound; and removable wear skids fixed to the radial extremities of said ribs.

6. In a stabilizer for drill pipe having tool joints along its length, said stabilizer being constructed for use in a well in which a drilling fluid is upwardly circulated, the combination comprising: a molded hard rubber bearing means to fit rotatably around the pipe, said bearing means being split throughout its length whereby it may be easily mounted in position around said pipe; spacer means surrounding said bearing means mounted rotatably with respect to said bearing means, said spacer means having straight longitudinal ribs to prevent substantial transverse movement of said drill pipe in the well, said ribs defining passageways between them enabling circulation of said drilling fluid upwardly in the well past said stabilizer, said spacer means being a solid cylindrical body having said ribs connected to its external surface and having an inside diameter greater than the outside diameter of the tool joints of said drill pipe, whereby it may be easily located at any position along said drill pipe; fixed means for limiting the axial movement of both said spacer means and said bearing along said pipe without limiting the rotational movement of said bearing means and said spacer means therearound; and removable Wear skids fixed to the radial extremities of said ribs, said wear skids being made of a hard material in comparison to aluminum, and said cylindrical body being made of a soft material in comparison to steel, said skids being attached to said ribs at a radial distance from said bearings to permit their severance by milling said cylindrical body in the space between said bearing means and said skids.

7. In a stabilizer for drill pipe having tool joints along its length, said stabilizer being constructed for use in a well in which a drilling fluid is upwardly circulated, the combination comprising: a molded hard rubber bearing means to fit rotatably around the pipe, said bearing means being split throughout its length whereby it may be easily mounted in position around said pipe; spacer means surrounding said bearing means mounted rotatably with respect to said bearing means, said spacer means having longitudinal ribs to prevent substantial transverse movement of said drill pipe in the well, said ribs defining passageways between them enabling circulation of said drilling fluid upwardly in the well past said stabilizer, said spacer means being a solid cylindrical body having said ribs connected to its external surface and having an inside diameter greater than the outside diameter of the tool joints of said drill pipe, whereby it may be easily located at any position along said drill pipe; and fixed means for limiting the axial movement of both said spacer means and said bearing along said pipe without limiting the rotational movement of said bearing means and said spacer means therearound, said fixed means including upper and lower members fixed to said drill pipe both above and below said bearing means of said cylindrical body, respectively.

8. In a stabilizer for drill pipe having tool joints along gara es" its length, said stabilizer being constructed for use in a well in which a drilling fluid is upwardly circulated, the combination comprising: a molded hard rubber bearing means to fit rotatably around the pipe, said bearing means being split throughout its length whereby it may be easily mounted in position around said pipe; spacer means surrounding said bearing means mounted rotatably with respect to said bearing means, said spacer means having longitudinal ribs to prevent substantial transverse movement of said drill pipe in the well, said ribs defining passageways between them enabling circulation of said drilling fluid upwardly in the well past said stabilizer, said spacer means being a solid cylindrical body having said ribs connected to its external surface and having an inside diameter greater than the outside diameter of the tool joints of said drill pipe, whereby it may be easily located at any position along said drill pipe; and fixed means for limiting the axial movement of both said spacer means and said bearing along said pipe without limiting the rotational movement of said bearing means and said spacer means therearound, said fixed means including upper and lower members fixed to said drill pipe, respectively, above and below said bearing means and said cylindrical body, said bearing means having a radially extending flange at its upper end to fit between the upper end of said cylindrical body and the lower end of said upper member.

9. In a stabilizer for drill pipe having tool joints along its length, said stabilizer being constructed for use in a well in which a drilling fluid is upwardly circulated, the combination comprising: a molded hard rubber bearing means to fit rotatably around the pipe, said bearing means being split throughout its length whereby it may be easily mounted in' position around said pipe; spacer means surrounding said bearing means mounted rotatably with respect to said bearing means, said spacer means having longitudinal ribs to prevent substantial transverse movement of said drill pipe in the well, said ribs defining passageways between them enabling circulation of said drilling fluid upwardly in the well past said stabilizer, said spacer means being a solid cylindrical body having said ribs connected to its external surface and having an inside diameter greater than the outside diameter of the tool joints of said drill pipe, whereby it may be easily located at any position along said drill pipe; and fixed means for limiting the axial movement of both said spacer means and said bearing along said pipe without limiting the rotational movement of said bearing means and said spacer means therearound, said fixed means including upper and lower members fixed to said drill pipe, respectively, above and below said bearing means and said cylindrical body, said bearing means having a radially extending flange at its upper end to fit between the upper end of said cylindrical body and the lower end of said upper member, each of said upper and lower members being clamps to embrace the circumference of said drill pipe.

10. In a stabilizer for drill pipe having tool joints along its length, said stabilizer being constructed for use in a well in which a drilling fluid is upwardly circulated, the combination comprising: a molded hard rubber bearing means to fit rotatably around the pipe, said bearing means being split throughout its length whereby it may be easily mounted in position around said pipe; spacer means surrounding said bearing means mounted rotatably with respect to said bearing means, said spacer means having longitudinal ribs to prevent substantial transverse movement of said drill pipe in the well, said ribs defining passageways between them enabling circulation of said drilling fluid upwardly in the well past said stabilizer, said spacer means being a solid cylindrical body having said ribs connected to its external surface and having an inside diameter greater than the outside diameter of the tool joints of said drill pipe, whereby it may be easily located at any position along said drill pipe; and fixed means ill for limiting the axial movement of both said spacer: means and said bearing means along said pipe without" limiting the rotational movement of said bearing means and said spacer means therearound, said fixed means ineluding upper and lower members fixed to said drill pipe,

' along its length, said stabilizer being constructed 'for use in a well in which a drilling fluid is upwardly circulated, the combination comprising: a molded hard rubber bearing means to fit rotatably around the pipe, said bearing including a plurality of cylindrical roller bearings mounted longitudinally of and in contact with said drill pipe to rotate about their own axes; spacer means surrounding said bearing means mounted rotatably with respect to said bearing means, said spacer means having longitudinal ribs to prevent substantial transverse movement of said drill pipe in the well, said ribs defining passageways between them enabling circulation of said drilling fluid upwardly in the well past said stabilizer; and fixed means for limiting the axial movement of both said spacer means and said bearing means along said pipe without limiting the rotational movement of said bearing means and said spacer means therearound.

12. In a stabilizer for drill pipe having tool joints along its length, said stabilizer being constructed for use in a well in which a drilling fluid is upwardly circulated, the combination comprising: a molded hard rubber bearing means to fit rotatably around the pipe, said bearing means including a plurality of cylindrical roller bearings mounted longitudinally of and in contact with said drill pipe to rotate about their own axes; spacer means surrounding said bearing means mounted rotatably with respect to said bearing means, said spacer means having longitudinal ribs to prevent substantial transverse movement of said drill pipe in the well, said ribs defining passageways between them enabling circulation of said drilling fluid upwardly in the well past said stabilizer;.fixed means for limiting the axial move ment of both said spacer means and said bearing means along said pipe without limiting the rotational movement of said bearing means and said spacer means therearound, upper and lower roller bearing housings fixed to said drill pipe respectively above and below said spacer means, said upper and lower housings having cylindrical recesses to receive rotatably the upper and lower ends of said roller bearings; and a cylindrical race located between said spacer means and said roller bearings, said race being maintained at a fixed axial, but rotatable angular position between said upper and lower housings.

13. In a stabilizer for drill pipe having tool joints along its length, said stabilizer being constructed for use in a well in which a drilling fluid is upwardly circulated, the combination comprising: a molded hard rubber bearing means to fit rotatably around the pipe, said bearing means being split throughout its length whereby it may be easily mounted in position around said pipe; spacer means surrounding said bearing means mounted rotatably with respect to said bearing means, said spacer means having longitudinal ribs to prevent substantial transverse movement of said drill pipe in the well, said ribs defining passageways between them enabling circulation of said drilling fluid upwardly in the well past said stabilizer, said spacer means being a solid cy1in-' drical body having said ribs connected to its external surface and having an inside diameter greater than the outside diameter of the tool joints of said drill pipe, whereby it may be easily located at any position along said drill pipe; fixed means for limiting the axial movement of both said spacer means and said bearing means along said pipe without limiting the rotational movement of said bearing means and said spacer means therearound, said fixed means including upper and lower members fixed to said drill pipe, respectively, above and below said bearing means and said cylindrical body, said bearing means having a radially extending flange at its upper end to fit between the upper end of said cylindrical body and the lower end of said upper member, each of said upper and lower members being clamps to embrace the circumference of said drill pipe; first dog means fixed to the upper end of said lower member extending upwardly towards said cylindrical body; and second dog means on said cylindrical body to engage said first dog means, each of said dog means being constructed to limit the rotational movement of said body with respect to said pipe to one direction when said dog means are forced into engagement with each other.

14. In a stabilizer for drill pipe having tool joints along its length, said stabilizer being constructed for use in a well in which a drilling fluid is upwardly circulated, the combination comprising: a molded hard rubber bearing means to fit rotatably around the pipe, said bearing means being split throughout its length whereby it may be easily mounted in position around said pipe; spacer means surrounding said bearing means mounted rotatably with respect to said bearing means, said spacer means having longitudinal ribs to prevent substantial transverse movement of said drill pipe in the well, said ribs defining passageways between them enabling circulation of said drilling fluid upwardly in the well past said stabilizer, said spacer means being a solid cylindrical body having said ribs connected to its external surface and having an inside diameter greater than the outside diameter of the tool joints of said drill pipe, whereby it may be easily located at any position along said drill pipe; fixed means for limiting the axial movement of both said spacer means and said bearing means along said pipe without limiting the rotational movement of said bearing means and said spacer means therearound, said fixed means including upper and lower members fixed to said drill pipe respectively above and below said bearing means and said cylindrical body, said bearing means having a radially extending flange at its upper end to fit between the upper end of said cylindrical body and the lower end of said upper member, each of said upper and lower members being clamps to embrace the circumference of said drill pipe; first dog means fixed to the upper end of said lower member extending upwardly towards-said cylindrical body; and second dog means on said cylindrical body to engage said first dog means, each of said dog means being constructed to limit the rotational movement of said body with respect to said pipe to one direction when said dog means are forced into engagement with each other, said bearing means being fixed to said cylindrical body, said bearing means extending downwardly below the lower end of said cylindrical body to contact said first dog before said second dog means engages said first dog means.

15. In a stabilizer for drill pipe having tool joints along its length, said stabilizer being constructed for use in a well in which a drilling fluid is upwardly circulated, the combination comprising: a molded hard rubber bearing means to fit rotatably around the pipe, said bearing means being split throughout its length, whereby it may be easily mounted in position on said drill pipe; spacer means surrounding said bearing means mounted rotatably with respect to said bearing means, said spacer means having longitudinal ribs to prevent substantial transverse movement of said drill pipe in the well, said ribs defining passageways between them enabling circulation of said drilling fluid upwardly in the well past said stabilizer; fixed means for limiting the axial movement of both said spacer means and said bearing means along said pipe without limiting the rotational movement of said bearing means and said spacer means therearound, said fixed means ineluding upper and lower clamps fixed to said drill pipe; and upper and lower hard rubber rings disposed respectively between the upper end of said spacer means and said upper clamp and the lower end of said spacer means and said lower clamp.

16. In a stabilizer for drill pipe having tool joints along its length, said stabilizer being constructed for use in a well in which a drilling fluid is upwardly circulated, the combination comprising: a molded hard rubber bearing means to fit rotatably around the pipe, said bearing means being split throughout its length, whereby it may be easily mounted in position on said drill pipe; spacer means surrounding said bearing means mounted rotatably with respect to said bearing means, said spacer means having longitudinal ribs to prevent substantial transverse movement of said pipe in the well, said ribs defining passageways between them enabling circulation of said drilling fluid upwardly in the well past said stabilizer; fixed means for limiting the axial movement of both said spacer means and said bearing means along said pipe without limiting the rotational movement of said bearing means and said spacer means therearound, said fixed means including upper and lower clamps fixed to said drill pipe, said hard rubber bearing means being clamped to said drill pipe at each end thereof by said clamps; and upper and lower hard rubber rings disposed respectively between the upper end of said spacer means and said upper clamp and the lower end of said spacer means and said lower clamp.

17. In a stabilizer for drill pipe having tool joints along its length, said stabilizer being constructed for use in a well in which a drilling fluid is upwardly circulated, the combination comprising: a molded hard rubber bearing means to fit rotatably around the pipe, said bearing means being split throughout its length, whereby it may be easily mounted in position on said drill pipe; spacer means surrounding said bearing means mounted rotatably with respect to said bearing means, said spacer means having longitudinal ribs to prevent substantial transverse movement of said drill pipe in the well, said ribs defining passageways between them enabling circulation of said drilling fluid upwardly in the well past said stabilizer; fixed means for limiting the axial movement of both said spacer means and said bearing means along said pipe without limiting the rotational movement of said bearing means and said spacer means therearound, said fixed means including upper and lower clamps fixed to said drill pipe, said lower clamp having first dog means fixed to its upper end extending upwardly towards said spacer means, said spacer means having second dog means to engage said first dog means, each of said dog means being constructed to limit the rotational movement of said body with respect to said pipe to one direction when said dog means are forced into engagement with each other; and upper and lower hard rubber rings disposed respectively between the upper end of said spacer means and said upper clamp,

and the lower end of said spacer means and said lower clamp.

References Cited in the file of this patent UNITED STATES PATENTS 1,890,529 Santiago Dec. 13, 1932 2,034,075 \Vright Mar. 17, 1936 2,079,449 Haldeman May 4, 1937 2,080,683 Yost May 18, 1937 2,288,124 Creighton June 30, 1942 2,308,316 Smith et al. Ian. 12, 1943 2,368,415 Grant Ian. 30, 1945 2,572,307 Brown et a1 Oct. 23, 1951 2,636,787 Medearis Apr. 28, 1953 2,663,599 Mackay et al Dec. 22, 1953 2,696,367 Robishaw Dec. 7, 1954 2,715,552 Lane Aug. 16, 1955 2,758,891 Kammerer Aug. 14, 1956 2,760,925 Bryant 2- Aug. 28, 1956

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