US1403388A - Underreamer - Google Patents

Description

R. L. BURNS.

UNDE'RREAMER.

APPLICATION FILED NOV. 29, 1920.

Patented Jain. MI 1922,

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ATTORNEY R. L. BURNS.

Patented Jan. ML, 1922.

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R. L. BURNS.

UNDERREAMER.

APPLICATION FILED NOV- 29, I920.

Patented Jan. M1922.

3 SHEEISSHEET 3' INVENTOR,

BY A I Iii) v V ATTORNEY UNHTEID) stares EQBERT I4. BURNS, OF THE, GALIJFQRINIA.

UNDER ncense.

Specification of Letters Patent.

Patented Jan. 141 1922.

Application filed November 29, 1920. Serial No. 426,949.

To all whom it may concern:

Be it known that 1, ROBERT L. BURNS, a citizen of the United States, residingat Taft, county of Kern, State of California, have invented a new and useful Underreamer, of which the following is a specification.

This invention relates to underreamers, and is particularly directed to underreamers such as are utilized in the process of drilling oil and other well bores by the reciprocatory or churn drilling method.

As is well known in this art, the wellboring or drilling tools which are employed in the reciprocatory method of drilling, only drill a hole of substantially the diameter of the interior of the casing. This leaves a shoulder or annular obstruction beneath the casing which must be removed before the casing can be lowered. For this urpose underreamers, provided with expanslble cutters or'slips, are employed, said underreamers being lowered through the casing afterv a period of drilling, with the slips 1n contracted condition. Such underreamers are generally constructed so that the cutters or slips automatically expand after passing the shoe or lower end of the casing, the casing being somewhat elevated above the shoulder to permit such expansion and to permit a commencement of the underreaming operation.

The present invention is directed particularly to that type of underreamer referred to in the trade as the Bowl-type, wherein the reamer body is recessed upwardly from its lower extremity providing an imperforate annular wall and a longitudinally extending cavity to receive and confine the shanks of a pair of opposed cutters or slips, the shanks being movable vertically and tiltable Within the body cavity to permit the slips to expand to cutting position and to be contracted from such position. In this type of underreamer it is desirable that the shanks of the slips be relieved of the major portion of the strains incident to the cutting operation, that the cavity of the body be of minimum proportion so as to provide a relatively thick annular wall, and t at the cooperating bearing surfaces of the wall and the slips be of such area and contour as to receive and transmit directly to the body, all strains and thrusts. At the same time the construction should be such as to avoid as far as possible the formation of irregularities or pockets in the cooperating surfaces or faces of the body and of the slips, such irregularities and pockets being diflicult to form and tending to cramp and obstruct the slips and to form open spaces for the collecting of sand and abrasive materials detrimental to the operation and life of the tool.

With the foregoing general requirements lll'l view, the object of the invention is to provide an underreamer of the Bowl type, having relatively large cooperating bearing surfaces between the slips and the body, to provlde perfect seats for the slips, to provide a construction in which the wearing surfaces will to a large extent be protected against the entrance of sand or other abrasive matter, and in which the major portion of the strains and thrusts incident to an underreaming operation are transmitted directly to the body.

Another object is to rovide an underreamer provided with shps having cutting edges of extensivecircumferential span and to provide an underreamer which will be superior in point of relative simplicity in construction and organization, taken in connection with reliability in collapsion, and expansion of the slips, positiveness of operation, simplicity and convenience in control and manipulation, compactness in form, durability as to the entire tool and particularly as to the length of effective life of the slips and other working parts, and which will be generally superior in efficienty and serviceability.

Various other objects and advantages will be more fully apparent from the following detailed description of the accompanying drawings which form a part of this disclosure, and which illustrate a preferred form of embodiment of the invention.

Of the drawings:

Figure 1 is an elevation of the underreamer of the present invention, the slips being in expanded positions.

Fig. 2 is an elevation taken at right angles to Fig. 1.

Fig. 3 is an enlarged vertical section, showing the slips in expanded positions.

Fig. 4c is an enlarged view, similar to the lower end ofFig. 2, showing the body in section.

Fig. 5 is a vertical section similar to the lower portion of Fig. 3, showing the slips in collapsed position, a ortion of one slip being broken away to il ustrate the full contour of the opposite slip.

1 1 3.3. l -ig. 7 is a plan section on line X -X" showing the slips in collapsed position.

of Fig. 3.

with the working parts removed.

commodatea suitable more 1" which the spring rod may b ulled ownward in of setting the slips in col apsed position; The F1 3, above described shank construction" and hig. 8 is a plan section on line X"-.-' X of pivotal connection provides slip members,

ig. 9 is a Fig. 6 is a plan section on line X -X" of vertical Section on line X9-X" ing, with a scissor-like movement;

Fig. 10 is a bottom plan view of the body bod is of the specific configuration shown f in 1 1, and may be formed by milling Fig. 11 is an elevation -similar to Fig, 1, straig t across the lower end'of the body,

-.With reference to the drawings, 1 desig grooves 20-20, the adjacent outwardly and nates the body of the underreamer, and2 downwardly angled u -thrust.bearing surthe sub to which the body is joined, said faces 21-21, and the intermediate expandsub having the usual tapered and threaded ing lugs 22-22, there. being two such lugs pin 3 by which the underreamer is attached (see' Fig. 10) by reason of the intersecting to the string of tools in the usual nianner. cavity 4. The lugs serve to positively ex- 1 The body isrecessed upwardly from 1ts pand the slips and. provide opposed sliplower extremity to form a substantially recexpandin "and in-thrust bearing. surfaces tangular cavity '4; adapted to receive thev 23-23, t e grooves 20-20 forming outrespective shanks of the slips and-the-lower thrust bearing surfaces 24-24 and the ad-' slip supporting end of the spring rod or ditional up-thrust bearin surfaces 25-25. mandrel 5. Said rod has a head 6 of rec- The upper surfaces 0 tangular cross sectional contour correspond-- are contoured to closely fit the bearing suring to the contour of the cavity 4, this prefaces of the body when in expanded posiventing the rod from turning, and a circular tion, they being rovided with transverse upper portion extendingupwardly through tongues 26-26 a apted to engage w1th1n -a, bore in the body, said bore having an the grooves 20-20 and providing angled enlarged upper portion providinga spring expanding and in-thrust bearing surfaces chamber 8. The upper end of the rod is 27-27,'and angled up-thrust bearing surscrew threaded to receive the nut 9 and a faces28-28 to engage the -up-t hrust bearing coil spring 10 surrounds the ,rod within the surfaces 21-21 of the body.

The contour of the lower surface of the the slips 14- 15 operating in their expanding and collapsthis providing two opposed transverse:

spring chamber, the'spring engaging the 'lhe body portionsof the slips are of a bottom wall of the chamber and a washer half cylindrical cross sectional contour pro- 11' beneath-the' nut 9. viding cutting edges of extension circum- Depending fromthe medial portion of the ferential span and the' side walls of the rectangular head 6 ofthe sprlng rod 5 is a slips are-correspondingly grooved as at 30 flat tongue 12 carrying a transverse pivot to accommodate a retaining band or strap, pin 13 as a means of pivotal support for the as indicated in dotted lines in Fig. 5, for slips 14-15. v the purpose of holding the slip in collapsed The sli s 14-15 have upwardly extending position while the tool is being inserted into flat shan slP-l5, said shanks being disthe well casing, according to a practice now posed 'to one side of the transverse centers well known in the art. Near their upper of their respective slips so that when assemends the slips have beveled shoulders 31, bled the shank of one slip will be positioned which when the underreamer is elevated to onone side of the tongue 12 and the shank cause 'a collapse of the slips, will engage of the opposed slip will be positioned on the the lower end of the casing, or casing shoe opposite side thereof, each shank being pivto hold the slips stationary while the body otally journaled on an opposite end of the 1 is being drawn u wardly and cam the pivot pin 13 and the combined thicknesses slips inwardly to co lapsed position for a of the two. shanks and the ton e e ualing withdrawal of the underreamer from the the corresponding dimension 0 the rectanwell. gular cavity 4, as indicated in Figs. 4 and 8. From the above and with particular ref- Each shank, between its pivoted center erence to Figs. 5 and 11 of the drawin and the top of'its. respective slip, is of a and considering that the spring 10 is un er width equal to the width of the cavity 4, tension, it will be evident that when the and above such pivoted center the side adlmderreamer is lowered in. the well casing jacent said slip is vertically angled inwardly, beyond the bottom thereof, the slips, then as at 16, to permit a tiltin of the slip, bem free to expand, will be translated upwhile the side opposite is relieved as at 17 war ly by the action of the spring 10, and to provide clearance against binding on the by reason ofthe cooperative cam action of mouth of the, cavity. The tongue 12 extends the bearing surfaces 27-23 will be positively downwardly into clearance recess 18 in the forced outwardly during such upward moveslips and has a transverse orifice 19 to acment.

' mosses the intermeshing tongues or grooves effectively prevent a ripping out of the slips under excessive out-thrust strains. The angled disposition of the up-thrust bearing surfaces is particularly advantageous in urging the slips to close en agement with the body surfaces when su jected to upthrust or in-thrust strains and contribute towards withstanding out-thrust strains.

The construction as above explained provides a bowl type of underreamer in which the central cavity has been reduced to a minimum diameter, leaving a thick strong bowl wall providing extensive bearing surfaces, and the slips are contoured to interlock in the grooves of the body and to provide a maximum span of cutting edge.

While the specific form of mechanism herein shown and described, is admirably adapted to fulfill the objects primarily stated, in is to be understood that it is not intended to confine the invention to the one form of embodiment herein disclosed, for it is susceptible of embodiment in various forms, all coming within the scope of the following claims.

What is claimed is follows:

l. In an underreamer, a body having an axial recess upwardly from its lowerextremity forming an imperforate bowl, a spring rod slidable within said recess, a transverse pivot pin carried b the rod, a spring functioning to elevate t e rod, and opposed slips having flat! shanks projecting upwardly in overlapping relation and pivotally journaled on the pivot pin, the body having transverse grooves in its under surface and the slips having transverse tongues for interlocking engagement with the companion grooves.

2. In an underreamer, a-body having an axial recess upwardly from its lower extremity forming an imperforate bowl, the lower face of the bowl formed to provide transverse grooves adjacent opposite sides of the recess, expanding lugs between the ends of the grooves and outwardly and downwardly extending transversely flat bearing surfaces outwardly of each roove, a rod slidable within the recess o the body, a spring functioning to elevate the rod, a pivot pin carried by the rod, opposed slips having flat shanks projecting upwardly into the recess in overlapping relation and pivotally supported on the pivot pin, the body portion of each slip having a transverse tongue and an adjacent bearing surlface adapted to engage the companion groove and bearing surface of the body on one side of the recess.

3. In an underreamer, a body provided with a recess having four vertical side walls and extending upwardly from its lower extremity to form an imperforate bowl, and an axial bore above said recess forming a spring chamber, a rod slidable in the recess and extending into the sprin chamber, said rod having a head contoure to slidably fit within the recess and a flat tongue depending from the medial portion of the head and of a width substantially equal to the width of the recess, opposed slips having flat shanks extending upwardly on opposite sides of the tongue and pivotally journaled to swing thereon, the combined thicknesses of the two shanks and the tongue being substantially equal to the corresponding dimension of the recess, and a spring in the spring chamber functioning to elevate the rod, the body having means for separating the slips during their upward movement.

4:. In an underreamer, a body having a substantially rectangular, recess upwardly from its lower extremit forming an imperforate bowl and an axia bore enlarged at its upper end to provide a spring chamber, the lower surface of the body having trans versely disposed grooves on opposlte sides of .the recew and formed to provide outwardly and downwardly angled bearing surfaces outwardly from said grooves, a rod slidable in the recess and bore, said rod extending upwardly into the spring chamber and having a rectangular head slidable in the recess and a flat tongue depending from said head, a spring in the spring chamber functioning to elevate the rod, and opposed slips having shanks extending upwardly into the recess on opposite sides of the tongue and pivotally connected thereto, the slips each having an upstanding transverse tongue adapted to fit into the companion groove of the body and an angled bearing surface extending outwardly and downwardl from said tongue and adapted to engage t e companion bearing surface of the body.

Signed at Taft, California, this 22d day of November, 1920.

. ROBERT L. BURNS.

Witnesses:

MARGUERITE CARMAOK, T. J. OBRIEN.

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