US2953351A - Mass vibration absorber for sonic oil well drill - Google Patents

Description

Sept. 20, 1960 A. s. BODINE ETAL 2,953,351

MASS VIBRATION ABSORBER FOR some on. wm. DRILL Filed Aug. 26. 1957 4 Sheets-Sheet 1 INVENTOR. 3% ALBERT 5. BOD y JAMES N. GREGG ATTORNEY Sept. 20, 1960 MASS VIBRATION ABSORBER FOR SONIC OIL WELL DRILL Filed Aug. 26, 1957 4 Sheets-Sheet 2 FIGS IINVENTOR. ALBERT G.BODINE BY JAMES N. GREGORY ATTORNEIV Sept. 20, 1960 A. G. BODINE ETAL MASS VIBRATION ABSORBER FOR SONIC OIL WELL DRILL Filed Aug. 26, 1957 4 Sheets-Sheet 3 INVENTOR.

DINE GORY P 1960 A. G. BODlNE ETAL 2,953,351

MASS VIBRATION ABSORBER FOR SONIC OIL WELL DRILL Filed Aug. 26, 1957 4 Sheets-Sheet 4 FIG. 9

INVENTOR.

ALBERT G. BODINE JAMES N. GREGORY ATTORNE United States Patent MASS VIBRATION ABSORBER FOR some OIL WELL DRILL Albert G. Bodine, 12130 Moorpark Sh, Van Nuys, Calif., and James N. Gregory, 5651 Sorrento Drive, Long Beach 3, Calif.; said Gregory assignor to said Bodgne Filed Aug. 26, 1957, Ser. No. 680,292

9 Claims. (Cl. 2'554.4)

This invention relates generally to deep well drilling, and more particularly to means for improving the drilling action of conventional rotary drag bits or roller cutter rock bits, especially for relatively irregular formations. In the operation of the conventional rotary bit such as .those of the toothed roller type, designed for and operating on relatively irregular formations, an undesirable relatively low frequency vibratory action is often encountered. Ideally, in this type of drilling, successive teeth of the cutters should cut their way into the forma tion :without elevation of the bit body and any part of the drill string above. However, in practice, the :bit rises and falls, due possibly to roughness of thehole bottom, slant of the formation, or other iactors. The kelly may be observed to rise and fall, with a relatively slow but regular periodicity. Obviously, during each rise, the cutters are not making proper progress through the formation. It may be mentioned that the periodicity observed under the conditions here described is not that of the contact frequency of individual cutter teeth with the rock, but is one of a lower order. Thus a number got cutter teeth may engage the rock during the cycle; but whenever the bit is not fully down, the cutter teeth do not .make the full cuts into the formation of which they are capable. The full explanation of the reason for {this eondition remains somewhat obscure but ,the condition is one often observed in drilling relatively uneven .or ir- .erator. The concept of the invention "is to couple to this generator, for-pant ofthe time duration of each vibration cycle, a mass impedance element, so as-to periodicall-y, i.e., one or more times each cycle, impose a mass loading on the generator, or bit. The mass element is thus repeatedly in and out of vibration transmission circult, so as -to;present a discontinuous impedance, much ,likea rectifier if placed in electronic oscillator circuit.

T he original vib t r ot nof he tmay he -regarded as substan y s soida i char ct Sudden imposit n of loa n .a se c c ,poih c po nt th cy l dest y t su t n i l y i so dal ave 1 n.

ipp n h avepeaksat ow amplitu a e ter-this the v into a hlineariqun con ain nga lar e number of "high frequency harmonics. The Q factor of the original wave is almost completely destroyed. In cgnsequence, vibration of thebit anddrill s tem is greatly rem ssive sleeve surrounding the drill stem between the 2 collars and bit, and provided at its lower end with impact shoulder adapted for engagement with an impact seatformed on the upper portion of the body of the bit, or on a member close to and tightly joined to the bit. The sleeve may ride normally on this impact seat. :If the bit should begin to vibrate at material amplitude, the sleeve shoulder and the bit seat separate; and on each succeeding upstroke of the bit, the impact bit seat strikes the sleeve shoulder. This usually happens as the sleeve is falling, so that there is considerable out-.of-phase relative motion. Thus, the bit is suddenly mass loaded, 'In other terms, a mass impedance is suddenly connected to the vibration generator comprised of the bit. On the downstroke of the bit, the impact surfaces separate, owing to the fact that the bit descends more rapidly than the sleeve. This tendency for the bit to descend quickly with an acceleration of more than one G is a result, most forms of the invention, of a downward bias force owing to a compressive elastic stress developed in the members connecting the bit to the drill string above. A td wnward bias is also exerted by the mud pressure inside the bit, ahead of where the mud issues from the bit nozjz le. This action very rapidly clamps out the large amplitude vibrations.

In another embodiment, the upper end of the sleeve a so as an mpact oul e w i s ap o en a ement w t adownwardly a ng mpact seat o th can s srh- T ha e eme ts cqme t engagement du in th downstroke. Thus mass loading is imposed at a point in th c l rin th p t ok and a a tsther Po i t e ycl du ih e 'd n tr ke- More r; th sleeve i moving up whe n e y the d scen in dr l stem, so thatenergy delivered from the drill stem to the s e on th str k s ne r mme to h drill s em to retard it on the downstroke. Similarly, energy deh m 0 sl ve 1 th d wn t pke o h il stem s e r e to th d i l s e n a t m of i p c an th upstroke to retard the upstroke. By virtue ,of energy conservation, a lighter sleeve may be employed.

A still further feature of one form of the inv erttign is to utilize a plurality of mass elements designed tgtrictionally slide or work on one another during vibratiqn conditions, with the eflect of introducing a frictio lresistance that consumes vibration energy (cpnverts it to heat). i i

The invention will be better understood by ,now referring to the fellowing detailed description of several illustrat-ive embodiments thereof, reference being had to the accompanying drawings, in which; i Fig. l is a longitudinal sectional view oi one embodiment of-the-invention; i

Fig. 2 is a transverse section taken on line 2 2 vof Fig. 1; 1

Fig. '3 is a transverse sectiontaken .on line 3,. 3 o t El'gwl; t 4 is an elevational view of another embodiment .Qf the-invention, the bit being broken away; 7

Fig. 5 is an enlarged longitudinal sectio al view of the embodiment of Fig. 4;

Fig. -6 is a transverse section on line 161-16 of Fig. .5 Fig. 7 is a transverse section on line 7- 7,of 1- ;ig. Fig. 8 is a transverse section on line 8-1 Qf Figfd;

' Fig. 9 is 'aview partly in elevation and partly lon itudinal section of another embodiment of the invent:

10 is a transverse section on line 10710 ofiFig. 9;and v Fig. '11 is a view similar to Fig. 10, but showing a modification.

Referring first to that embodiment of our inventtqn shown on Figs. 1 to 3, numeral 18 designates generally the lower end portion of a rotary drill shaft, the lower -end-portion ofa conventional string of drill collars being 'more rapidly than the sleeve.

shown at 20, and the upper end of these collars will be understood to be coupled to the drill pipe string above in the usual manner. Collars have the usual circulation bore 20a. Screwed onto the coupling pin 21 at the lower end of lowermost collar 20 is a sub 22 formed with a central bore 23, in which is welded the upper end portion of a tube 24 of reduced diameter, the lower end of which is welded to a lower sub 25 having at the bot-tom a threaded box 26 adapted to receive the pin 27 on the upper end i of conventional toothed roller cone bit 28, the latter having, for example, a conventional toothed conical roller cutters 29, of which there may be two, three, or four, as in conventional bits. Upper sub 22 has a downwardly :converging conical impact surface 30 leading inwardly to tube 24, and lower sub 25 has an upwardly converging conical impact or seating surface 31 leading inwardly toward the tube 24, as shown.

Surrounding the tube 24 between the subs 22 and 25 is a relatively massive sleeve 32, having at its lower end a conical impact shoulder 33 opposed and parallel to the aforementioned surface 31 on lower sub 25, and having at its upper end a conical impact shoulder 34 opposed and parallel to the aforementioned conical surface 30 on :upper sub 22. The surface 33 will be understood to seat normally on the seating surface 31 on sub 25, and

by relative upward movement of sleeve 32, the shoulder 34 at the upper end of the sleeve may engage or impact against the seat 30 on upper sub 22. In the position illustrated in Fig. 1, the sleeve 32 is in an intermediate position of operation, with its shoulder 33 spaced by a 'short clearance distance from seat 31, and with its upper .shoulder 34 also spaced by a short clearance distance from upper seat 30.

Preferably, in order to key the sleeve 32 against relative rotation with respect to the balance of the drill stem, and in this manner provide mass impact loading for any torsional vibrations, the conical seat 31 on the lower sub is provided with a plurality of ribs 35 (see Fig. 3), received loosely in slots 36 formed in shoulder 33. Similar ribs and slots may be used at the upper end of the sleeve 32 if desired, although such are omitted from the present drawings.

The specific embodiment shown in Figs. 1 to 3 has coacting engagement or impact surfaces 31 and 33 at the lower end of the sleeve 32, and additional coacting engagement or impact surfaces 30 and 34 at the upper end of the sleeve. In a simpler form of the invention, the engagement surfaces 39 and 34 may be omitted, in which case the sleeve may be terminated, for instance,

' at the level indicated in dot-dash lines at a.

to be set into vibration. Prior to such vibratory action,

the sleeve 32 will be understood to have been riding on the bit body with its seating shoulder 33 in engagement with the seat 31. As the bit suddenly starts to vibrate, the sleeve 1s thrown upwardly, or separates, from the seat 31. Thereafter, on each upstroke of the bit, the seat 31 impacts against the shoulder 33 on the sleeve, whereby the bit is suddenly loaded by the mass of the sleeve. On the ensuing downstroke of the bit, the impact surfaces 31 and 33 separate, owing to the fact that the bit descends Such relative retardation of the sleeve relative to the bit may be owing to the enveloping upwardly flowing drilling fluid, or to a downward acceleration of the bit owing to the internal pressure of the conventional drilling mud fluid, or to elastic vibration of the tube 24 or to all these factors in combination. On the next upstroke of the bit, the surface 31 again impacts against the sleeve surface 33, and so on. This repeated coupling of the mass element 32 with the bit 28 rapidly damps out the vibrations. It will be understood that if the mass element were fixed to the bit, it would be set into vibration along with the bit, and no very great damping effect would be accomplished. It is the fact that the mass element is discontinuously coupled with the vibratory bit that suppresses the vibration. As earlier described in the introductory portion of the specification, the bit tends normally to vibrate with a substantially sinusoidal Wave action. The sudden imposition of mass loading on the bit as the bit travels upwardly clips the wave peaks at low amplitude, and converts the Wave of vibration into a nonlinear form containing a large number of high frequency harmonics. The Q of the vibratory system is virtually destroyed. Vibration of the bit and drill stem is thereby materially reduced, or virtually eliminated. The drill cutters settle down to smooth, nonvibratory cutting action, with materially increased penetration rate.

In the operation of that form of the invention described immediately above, the mass element 32 engages the drill stern once during each cycle of the vibration, and disengages therefrom at a later point in the cycle.

The operation of the drill of Figs. 1 to 3 will next be described with the assumption that the impacting surfaces 30 and 34 are employed. In this case, action on the upstroke is substantially as before. On the downstroke of the bit and drill stern, however, impact surface 30 engages the upper impact shoulder 34 of sleeve 32.

Thus, mass loading is not only imposed on the drill stem at a point in the cycle during the upstroke, but at a subsequent point in the cycle during the downstroke. Owing to engagement of the lower end of the sleeve by the impact surface 31 during the upstroke of the bit and drill stem, the sleeve is thrown upwardly somewhat, and is still moving upwardly when the drill bit and stem have reversed direction and start downwardly. Accordingly, the descending drill stem strikes the still ascending sleeve, so that energy delivered from the drill stem to the sleeve on the upstroke is nowreturned to the drill stem to retard it on the downstroke. Similarly, energy delivered to the sleeve on the downstroke of the drill stem is returned to the drill stem at time of impact on the upstroke to retard the upstroke. By virtue of this energy conservation, a lighter sleeve may be employed.

Figs. 4 to 8 show another illustrative embodiment using a helical form of mass impedance element, the several turns of which are made both heavy and flexible so as to interengage with each other to impose discontinuous mass loading on the bit when vibratory conditions occur.

The lower end portion of the usual string of drill collars is indicated at 40, and coupled thereto, as by coupling 41, is the upper end of a long tubular member 42, having a helically slotted section 43, and to the lower end of which is coupled the bit, fragmentarily indicated at 44.

.The bit may be of any conventional or suitable toothed roller cutter type, or any other, as before.

the same diameter as the drill collars above, formed at the top with threaded coupling pin 46 for connection with the box of coupling 41. Below stem 45 is the helically slotted section 43, of enlarged outside diameter, and a bore 47 extends upwardly through this helically slotted portion and up in stem 45 to a blind end 48. The section 43 is formed, in the present case, by means of four spiral slots 49, forming quadruple pitch coil member comprised of four relatively heavy but flexible, close spaced spiral bars 50 connecting the stem 45 with a base annulus 51-. These bars so formed are massive and have a large amount of lateral surface for active engagement when the bars deflect laterally. Moreover, the slots are narrow.

The four spiral bars 50 are hollow, forming mud fluid passageways 5 2. This formation may be provided by s first grooving the bars 50, and then welding spiral filler strips 53 into place, as shown.

The upper ends of the several passageways communicate with the lower ends of passageways 54, and the upper ends of the latter communicate via passageways 55 with a bore 56 extending downwardly through coupling pin 46. It will be understood that the bore 56 is thus in communication with the circulation mud fluid passageway extending downwardly throughthe drill stem and collars above. The passageways 54 are formed in this instance *by vertically grooving the sides of stem 45, and then welding filler strips 57 in place, as illustrated.

Engaging the lower end of annulus 51 is a mounting flange 60 of a long connecting mandrel 61 that extends upwardly, with clearance, through the bore of the coils and the stem 45. Welded to the top of mandrel 61 is a head 62, which engages a transverse wall 63 extending across stem 45, and head 62 and wall 63 are interconnected, as by means of stud 64 and jamb nut 65. The lower end of mandrel 61 is closed by a Wall 66, and is joined to flange 60 by a generally conical wall member 67. This wall member 67 will be seen to be received snugly within the aforementioned base annulus 51. A bit coupling member 68 has a shoulder engaging the flange 60, and screws 69 secure the coupling member 68, flange 60, and annulus 51 in assembly. The coupling member 68 is formed with a tapered and threaded socket to receive the coupling pin 70 at the top of the bit.

Bores 71 through wall 67 and extending into annulus 51 will be seen to communicate with the fluid passageways 52 through the several bars of the coil members, so that the circulation passages downwardly through the spiral bars 50 are thus continued to the space 72 above the upper end of the coupling pin 70 at the upper end of the bit, to be thence continued downwardly through the usual circulation passage in the bit, as indicated.

In the operation of the embodiment of Figs. 4 to 8, vibration of the bit results in relative movement of the turns of the flexible coil elements 50 with respect to each other, causing them to interengage It will be seen that the drill stem is continued downwardly from the lower end of the collars through the'coupling 41 to the upper end portion of stem 45, and thence via walls 63 and 62, to and through the fairly heavy walled mandrel 61 to the bit. The coil elements 50 are, by comparison, relatively flexible in their lateral vibration, and capable of a substantial degree of independent vibration. Upon inception of bit vibration, vibrations are transmitted to both ends of the several coil elements 50, to the lower end through the coupling means connected to the base annulus 51 of the coils, and to the upper end through the mandrel 61, and back down the long stem 45. It will be seen that both ends of these coils are fastened basically to the same element. In addition, owing to the irregular engagement action of the several cutters on the hole bot tom, the vibration occurs in various modes and with various lateral and torsional as well as longitudinal components. Moreover, owing to these irregularities, and dilferent lengths of vibration transmission paths from the cutters to the coil elements, these elements vibrate in diverse phase relations in various longitudinal, lateral and torsional modes. Owing to these irregularities, the several heavy coil elements interengage, impact, or rattle against one another under conditions of substantial bit vibration. In addition, the fluid within the coils is caused to impact against the sides of the coil passages because of the lateral orientation thereof. These impacts result in irregular, intermittent mass loading of the bit, with vibration deterrent effects similar, in general, to those described in connection with the first described embodiment.

It is important to recognize that the inductive mass must be heavy. As the bit rolls along the bottom of the hole it generates vibrations in the drill stem above. These vibrations have an approximate frequency. If the high- 6 est component of this frequency number is divided into the number representing the speed of sound in the material of which the drill stem is composed, a quotient will be determined which can, for the purpose of this discussion, be called wavelength. (This does not imply that a discrete wave pattern is generated in the drill stem.)

The equivalent length of the vibration portion at the bottom of the drill stem itself is something of the order of one eighth of this quotient. Our inductive mass is advantageously of this order of magnitude in weight for those situations where the bit gives out something like a characteristic frequency. We have found in most instances our loo'se inductive mass should be at least 420 pounds.

With reference now to Figs. 9 and 10, a further embodiment of the invention. is shown, comprising ,a mass and resistance dampener unit adapted to be interooupled between the lower end of the drill collars, not shown, and the bit, fragmentarily indicated at 81. The device 80 comprises upper and lower coupling heads 82 and '83, respectively, the former formed with a threaded box 84 to receive the coupling pin at the lower end of the collars, and the latter formed with threaded box 85 to receive the threaded coupling pin 86 of the bit. Heads 82 and 83 are interconnected by a tubular housing 87, which may be Welded thereto, as indicated. Heads 82 and 83 have circulation passages 88 and 89, and a central tube fitted into heads 82 and 83 around passages 88 and 89 conveys the circulation mud fluid between passages 88 and 89.

In the annular space .inside housing 87 and around tube 90 are positioned a plurality of vertically disposed mass elements in the form of steel bars 94, which may be of trapezoidal cross section, so as to nest together nicely, as shown in Fig. 10. The bars 94 are dimensioned-to fit loosely with one another and with the tube 90 and housing wall 87, as clearly illustrated. The lower ends of the bars normally engage and stand on an impact seat 95 formed at the top of lower head 83, while the upper ends of the bars are adapted for engagement with the downwardly facing impact surface 96 on the lower end of upper head 82. The bars 94 are of such lengths as to provide clearance between their upperends and the upper impact surface 96 when resting on the lower impact surface 95; and in the operation of the device, upon inception of bit vibration, the bars 92 move between the surfaces 95 and 96, impacting first against one and then the other, as well as sliding frictionally against the surface of Wall 87 and tube 90, and to some extent on one another.

The operation of the embodiment of Figs. 9 to 11 is similar in general to Figs. 1 to 3, and will not require repetition. In addition, however, the movement that occurs between the plurality of bars 94 relative to one another, and to the wall 87 and tube 90, results in a material extent of frictional sliding resistance, with corresponding energy consumption. This energy consumption is a material additional deterrent to bit vibration, over and above the mass loading factor. In this case, therefore, a plurality of mass elements act to provide intermittent or discontinuous mass loading on the bit, and act also to provide a means of consuming bit vibration energy owing to frictional resistance between the mass elements sliding on one another and on the Wall surfaces of their housing.

Fig. 11 is a view similar to Fig. 10, but showing a modification wherein the bars are made with smaller cross sectional area, so as to permit increase in their number, and resulting increase in surface contact area between the bars, with the effect of increasing the frictional resistance factor. Thus, an outer ring of trapezoidal bar elements 94a surrounds an inner ring of trapezoidal bar elements 9411. It will further be understood that the bars may be further subdivided, or other configurations employed to increase the frictional resistance factor.

longitudinally so as to comprise a greater number of in :dividual bodies.

Moreover, these elements -may be subdivided Various illustrative forms of the invention have'now been illustrated and described. It will be understood, of

course, that the examples given are for illustrative purposes only, and that various changes in design, structure,

and arrangement may be made without departing from the spirit and scope of the invention as defined by the appended claims.

We claim:

1. In a rotary system for drilling a well bore, the combination of: a rotary drill shaft, a bit on the end of said shaft, which bit tends to develop undesirable vibrations when drilling, and which is subject to a bias force in addition to the weight of the bit tending to urge the bit toward the hole bottom, a bit vibration dampener comprising a mass element freely movable relative to a .lower portion of said shaft in a direction longitudinally thereof, and in out-of-phase relation to bit vibration motion, an impact seat on said shaft normally supporting 'said mass element and adapted to alternately separate from and impact thereagainst upon occurrence of bit vibration, and guiding means on said shaft laterally confining said mass element from contact with the wall of engageable with the lower end of said sleeve.

3. The subject matter of claim 2, including also a downwardly facing shoulder on said drill shaft above said sleeve and engageable with the upper end thereof, the distance between said shoulders exceeding the length of said sleeve by an amount such that said shoulders alternately impact against said sleeve in response to bit vibration.

4. In a rotary system for drilling a well bore, the combination of: a rotary drill shaft, a bit on said shaft,

which bit tends to develop undesirable vibrations when drilling, and which is subject to a bias force in addition to the weight of the bit tending to urge the -bit toward the hole bottom, an inertia means carried by said shaft for relative movement thereon, and being arranged to move in out-of-phase relation to bit vibration motion, to intermittently deliver impacts against, and thereby intermittently mass load, the drill shaft and bit in response to vibration of the bit and shaft whereby to quell such vibration, and guiding means on said shaft laterally confining said inertia mass from contact with the wall of said wall bore during drilling.

5. The subject matter of claim 4, wherein said inertia means is arranged for free longitudinal movement on said shaft between impact shoulders on said shaft spaced apart by a distance such that said inertia means impacts alternately thereagainst in response to vibration of the bit and shaft incident to drilling.

6. The subject matter of claim 4, wherein said inertia means comprises a plurality of mass elements adapted to frictionally Work against one another in response to said vibration of the bit and shaft.

7. The subject matter of claim 6, wherein said inertia means comprises a plurality of vertical bars nested together. I

8. The subject matter of claim 7, wherein said guiding means comprises a jacket on said shaft surrounding said vertical bars. 4

9. The subject matter of claim 1, wherein said drill shaft includes a drill collar, and a stem section extending downwardly from the lower end of said collar, and wherein said bit is attached on the lower end of said stem section, with said impact seat located on said stem section immediately above said bit, and wherein said mass element is located below said collar.

References Cited in the file of this patent UNITED STATES PATENTS 2,126,075 Wright Aug. 9, 1938 2,325,811 Terrell Aug.'3, 1943 2,542,725 Stewart et a1 Feb. 20, 1951 2,570,577 Manion Oct. 9, 1951 2,712,435 Allen July 5, 1955 UNITED STATES PATENT OFFICE CERTIFICATION OF CORRECTION Patent No. 2,953,351 September 20, 196

Albert G. Bodine et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

In the drawings, Sheets 1, 2, 3, and 4, and in the heading to the printed specification, lines 2 and 3, title of invention for "MASS VIBRATION ABSORBER FOR SONIC OIL WELL DRILL" read MASS VIBRATION ABSORBER FOR OIL WELL DRILL Signed and sealed this. 25th day of April 1961.

(SEAL) Attestz- ERNEST W. SWIDER Attesting Officer DAVID L. LADD Commissioner of Patents

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