US2956626A

US2956626A - Apparatus for freeing stuck pipe

Info

Publication number: US2956626A
Application number: US601579A
Authority: US
Inventors: Elmer D Hall
Original assignee: Individual
Current assignee: Individual
Priority date: 1956-08-01
Filing date: 1956-08-01
Publication date: 1960-10-18
Anticipated expiration: 1977-10-18

Description

Oct. 18, 1960 E. D. HALL 2,956,626

APPARATUS FOR FREEING STUCK PIPE Filed Aug. l, 1956 3 Sheets-Sheet 2 v i 5 5' E l 2.9 4 i y ,d

A /lllmrllllllll/'fl/ll/ t INVENToR. .f5/mep /a// Oct. 18, 1960 E. D. HALL APPARATUS FOR FREEING sTucK PIPE 5 Sheets-Sheet 3 Filed Aug. 1, 1956 TTOKNEK INVENTOR. E//We Ha# United States Patent.

APPARATUS FOR FREEING STUCK PIPE Elmer D. Hall, 401 Norton St., Weatherford, Tex.

Filed Aug. 1, 1956, Ser. No. 601,579

13 Claims. (Cl. 166-177) This invention relates to methods and apparatus for freeing stuck pipe in well bores and refers more particularly to such methods and apparatus wherein a rigid metallic length is forced through the pipe to be unstuck, the metallic length having at least a portion thereof crooked or deformed and of suicient rigidity to deform the pipe to be freed as it is forced therethrough.

Stuck pipe in this disclosure is to mean any type of pipe which has been lowered into ak well bore for the purpose of drilling for, or production of, water, oil, gas, etc., and has become lodged in the well bore in such a manner that it cannot be lowered or withdrawn by present methods of longitudinal tension (pulling on the pipe to its yield point) or compression (applying the weight of the free pipe in the well bore downwardly upon the lodged or stuck pipe). Thus, the term stuck will describe pipe lodged in a well bore under the conditions described above.

One of the major concerns in finishing an oil Well -is sticking of the pipe and actually getting the pipe to the bottom of the hole. It would be extremely desirable to be able to guarantee a job of getting the pipe to the bottom or keeping it free in the well bore if it is to be removed therefrom. Previously, this has not been possible.

A number of conditions can actually happen in a well bore to stick pipe therein. enumerated as follows:

(-1) Where loose formations such as sand or shale have settled around the pipe in the annulus between the outside of the pipe and the face of the well bore in a sucient quantity to cause enough friction that the pipe cannot be moved longitudinally or in rotation.

(2) Where a coupling or any other device that is on the pipe which is of a larger diameter than the pipe becomes lodged in what is referred to in oil well drilling terminology as a key seat. A key seat is actually an enlargement in one side of the drilled Well bore caused by the movement of the pipe, either in rotation or in longitudinal movement, against the inside curve or bend opposite a bend or curve in the well bore. In such a condition, the pipe is held against the inside curve or bend by the tension of pipe hanging below it, causing` the pipe to wear away that side of the well bore to the same size of the pipe itself. In other words, a key seat is an attempt by the pipe in tension to straighten out or remove any deviations of the well bore from a straight line. Under these conditions, any object of a larger diameter than the size of the Well bore at this key seat will tend to become wedged when forced into it. In actual oil well drilling practice, the size of a key seat is determined by the tool joints or couplings on the drill pipe, and it is usually anydevice that has a larger diam.- eter than the tool joints that may become lodged therein.

(3) Where large objects in the hole, such as boulders, or broken or lost pieces of drilling tools become wedged between the pipe and the well bore, causingv the pipe to stick.

These conditions can be ICC (4) Yet another condition in a well bore which may stick pipe is differential pressure. In differential pressure high pressure liuid in the annulus between the casing and the well bore flows into a porous subterranean formation which has a natural pressure far less than that of the annulus fluid. When this condition occurs, the casing cleaves or seizes to the permeable portion of the borehole wall under the inuence of the differential pressure. If the casing actually comes into contact with Athe porous or permeable formation, it acts as a seal over a greater or lesser area thereof and is thus forced against that region by an amount equal to the annulus pressure minus the formation pressure times the actual area of contact between the casings exterior wall and the wall of the well bore. Thus, for example, if the annulus uid pressure exceeds the formation pressure by 1.800 pounds per square inch, while the area of casing and borehole wall contact is 500 square inches, the casing will be driven against the borehole Wall by a total force of 400,000 pounds. It is obvious, that as long as these conditions are maintained, there is little hope. of moving the casing further into the bore or removing it therefrom. The reason for this is, in the latter case,..that both the casing weight and the shear strength of the contact plane must be overcome.

One of the great problems in oil well drilling is to salvage stuck pipe. Hundreds of millions yof dollars of pipe are left in wells every year and only approximately 30% of the total pipe set in wells can be salvaged at present. Up to the present time, it has been possible only to salvage the casing down to the first oil sand in a multiple oil horizon well because the first sand or any permeable, area thereabove causes sticking ofthe pipe by differential pressure.

Therefore, an object of the invention is to provide method. and apparatus for freeing pipe which is stuck in a Well bore etciently and dependably.

Another object of the invention is to provide method and apparatus for freeing pipe stuck in a well bore whether the pipe is stuck due to settling of well material, key seat engagement, Wedging or differential pressure.l

Another object of the invention is to provide apparatus for freeing pipe stuck in a well bore wherein the apparatus may be either xed to the drill stem andy lowered to the obstructed portion of the pipe thereon or forced there by hydraulic pressure.

Another object of the invention is to provide method and apparatus for freeing pipe stuck in a well bore wherein pipe. stuck in a plurality ofl positions in a Well bore can be freed and, particularly, pipe stuck against a plurality of permeable sands by differential pressure can be freed.

Another object of the invention is to provide method and apparatus for freeing pipe stuck in a well bore which will greatly increase the percentage quantity of pipe which is salvageable from well bores, such salvage saving great quantities of both money and metal.

Another object of the invention is to provide method and apparatus for freeing pipe `stuck in boreholes, the method and apparatus being applicable to free cemented pipe Where the bond is not complete or the cement has been contaminated, for example, it being common in oil well cement jobs t-o have several hundred feet of contaminated cement at the top of the cement portion. p Other and further objects ofthe invention will appear in the course of the following description thereof.

In the drawings, which form a part of the instant specification and are to be read in conjunction therewith, embodiments of the invention are shown and, in the various views, like numerals are used to indicate like parts.

Fig. 1 is a cross-sectional view through an earth formation containing a permeable horizon therein, a-casingk Fig. 2 is a cross-sectional view through an earth formal' tion having a permeable formation therein, a casing shown run in a well bore below the permeable horizon, a second modication of the inventive apparatus for freeing stuck pipe in the well bore being shown positioned within the casing immediately above the stuck portion thereof.

Fig. 3 is a cross-sectional View through an earth formation showing a permeable formation therein, a casing having been run in awell bore below the permeable formation and having become stuck thereto by differentiall pressure, a third modification of the inventive apparatus for freeing stuck pipe shown positioned within the casing, the operative portion of the apparatus being positioned opposite the permeable area.

Fig. 4 is a cross-sectional view through an earth formation having a permeable formation therein, a casing having been run in a well bore below the permeable formation and a fourth modification of the invention being shown positioned therein with the operative part` of the apparatus positioned opposite the permeable area.`

Fig. 5 is a view taken along the line 5-5 of Fig. 4

Y in the directionof the arrows.

Fig. 6 is a cross-sectional view through an earth forma- -a permeable formation 11 therein.

It is assumed that the pressure of the permeable formation is less than that of the annulus so the annulus iiuid tends to flow thereinto. Casing 13 is run in borehole 12 below the permeable formation 11 and, due to the well bore condition of differential pressure, adheres to the permeable formation as shown at 14. It is assumed that neither tension nor pressure upon the casing is able to free it from the differential pressure area. Therefore, the inventive apparatus for freeing pipe in a well bore is run into the casing to the vicinity of the stuck portion thereof. In this instance, the apparatus comprises a cylindrical, solid length or crank of metal 15 which has an outer diameter slightly less than the inner diameter of the pipe to be freed, and a threaded upper end 16 to be engaged with the threaded lower end 17 of the drill stem 18. The length 15 is crooked, bent or curved as at 15a over at least a portion thereof to a width greater than the internal diameter of the pipe to be unstuck and is of sufficient strength and rigidity to deform the pipe to be freed as it is forced therethrough. Preferably, the length is crooked, bent or curved centrally and has an essentially uniform slope on either side of the area of greatest bend up to the straight end portions 15b and 15C. The width of the crooked or curved portion of the length must be less than the smallest diameter of the well bore to be passed through by the crank to reach the stuck tion having a permeable formation therein, a casing having been run in' a well bore below the permeable i formation, a fifth form of the inventive apparatus for j unsticking pipe positioned within the casing, the operative portion of the apparatus being positioned opposite the permeable formation.

Fig. 7 is a cross-sectional view through an earth forma-1'" t tion having a permeable formation positioned therein, a casing having been run in a well bore below the permeable formationv and a sixth form of the inventive apparatus The invention comprises a preferably cylindrical length for unsticking pipe being shown positioned within the casing.

length crooked, bent or curved in at least a portion theref t of to a Width greater than the internal diameter of thel pipe to be freed and of suicient strength or rigidity to deform 'the pipe to'be unstuck as it is forced therethrough. There are two basic modiiications of the invention.

rotary drill stem at the upper end thereof to be lowered at the end of the drill stem into the pipe to be freed to the stuck portion thereof. This modification of the invention is shown in Figs. l-5.

The flrstand preferred modification of the invention is such a length adapted to be attached to a y distor-t the stuck pipe to pass its elastic limit.

When the curved or...

crooked crank has been so lowered to the vicinity' of thejammed portion of the pipe to be freed, it may be rotated at thelower end of the drill stem to free the pipe from the obstructed area.

The second modification of the invention, which isA u shown in Figs. 6 and 7, comprises such a described length of metal having means atthe top thereof to permit the j length to be forced down the pipe to be freed by hydraulic pressure. This form may not be rotated in the vicinity ,of or at the stuck portion of the casing and, thus, must rely merely upon the effect of the motion of its form i "i through the obstructed portion of the pipeto free it. Certain structural changes may be employed in both of the two basic modifications and will be set forth in detail in the following:

Referring iirst to Fig. l, therein is shown a firsty mod iiication .of the drill `stern suspended apparatus .for `unsticking pipe. At 10 is shown an earth formation having applied at the wellhead.

portion of the pipe. If surface casing or pipe has been set, the width of the crooked portion of the length must be less than the internal diameter of the surface pipe as well as the internal diameter of the hole bore. The

`length of the crank or length 15 is not critical but is the weight of the drill stem pipe becomes sufficient to force it through the casing without extra force being It is evident that the entire casing traversed by the crank 15 will be deformed as it passes therethrough in the manner shown in Fig. l; that is, the casing takes the shape of the crank as the latter passes through it. It is desirable that the width of the crook and the length thereof be such that the casing does not pass its elastic limit in its deformation, but, in some extreme circumstances, it may be necessary to employ a crank or eccentric length of a form that will In a preferred variation of the method, the crank or length 15 is forced downwardly through the casing 13 until the f crooked or curved portion 15a of the length approaches the stuck portion of the pipe. Before the crooked portion 15a of the crank` reaches the stuck portion of the pipe, rotation of the crank is begun by rotating the drill stem 18. Then, gradually, the crank 1S is moved downwardly, continuing rotation, until the crooked portion 15a is opposite the cleavage area. In this way, the destruction of the cleavage plane of the casing 13 to the formation 11 will be progressive rather than entire and simultaneous. The crank may be moved entirely below the stuck portion in rotation if desired. When the casing 13 is wedged, blocked or in a key seat, it is easy to see that such rotation will serve to break up and displace the Wedging material to free the pipe. In a differential pressure sticking, the passage of the well bore iluids into the permeable zone packs and dehydrates the mud in the .well bore against the permeable zone and, once the casthe formation pore space and serve to sealoff the permeable formation even more and, thereforethe tendency will be for the casing not to restick. i

When there are several permeable formations or stuck portions of the casing, the crank or length should be forced first above the rst stuck zone, then rotated and moved into the stuck zone to free it. Once that zone has been cleared, the crank is then forced downwardly to a position above the second zone, rotation begun and then the crank moved into the zone while rotating. In this manner, the pipe may be freed from an indefinite number of stuck zones and the running of the casing to the bottom of the hole or its removal. from the hole may be guaranteed. Once the stuck areas have: been freed, the drill stern and crank arewithdrawn from the casing. Contaminated or faulty cement jobs will sometimes leave casing or pipe in such a condition of adherence to the well bore that the inventive crank may be ableto beat several hundred feet of the casing free from the faulty bond to permit the recovering thereof. In some situations, however, and this is a variation of the method, it may be desirable to actually move the crank downwardly into the obstructed portion of the. pipe before rotation thereof is begun.

In Fig. 2 is shown a modification of the drill stem attached form of the crank or length wherein the actual length is a hollow tube threaded at the upper end thereof to attach to the drill stem. In Fig. 2, 19 indicates the earth formation, 20 a permeable formation therein, 21 shale or other debris which has wedged the casing 22 adjacent the permeable formation and 23 the well bore which has been drilled below the formation. Tubing 24 has hollow annulus 25, crooked, bent or curved portion 24a and an open lower end with threaded portion 26 at the upper end thereof to engage the threaded portion 27 of drill stem 28. The crank 24, although hollow, must be of sufficient strength to deform the casing 22 to its shape as in the modification of Fig. l. While in the Fig. l modification, the crank or length 15 was formed to an outer diameter only slightly less than the inner diameter of the casing so as to deform the casing 13 essentially uniformly without putting too great a stress on limited areas of the casing, Fig. 2 shows a modification of the invention wherein bearings are employed at the contact points between the crank and the casing to minimize wear on the tool or crank 24. In such a case, the crank itself is generally of proportionately less outer diameter relative the inner diameter of the casing Whereby to have bearings 29 of sufficient lthickness to stand long term wear. The bearings 29 are of an outer diameter less than the inner diameter of the casing 22 whereby to permit forcing of the crank down through the casing with the only deformation of the casing being due to the crooking or bending of the crank itself. The bearings 29 are preferably positioned at the area of greatest bend of the crank and at the ends of the bent portion thereof, which areas normaly will carry the friction of insertion, forcing through the pipe and rotation therein. Additional bearings may be required between the central bearing and the end bearings if the crank is of unusual length.

The operation of the Fig. 2 modification is the same as that of the Fig. l modification with the bearing mounted, hollow tube crank 24 being threaded onto the drill stern, forced down the casing 22 to the vicinity of the stuck portion of the pipe and rotation thereof within the casing begun either before or after the bent por-tion of the crank is forced into the stuck portion of the casing. It should be noted, that the Fig. 1 modification, that is, a solid bar crank or length, could be employed with bearings of the same type as Fig. 2 merely by employing a solid bar of slightly lesser diameter and fixing the bearings thereto. Additionally, the Fig. 2 modification,V a hollow tube, could be employed without bearings the differences noted, the construction, form, strength and operation of the Fig. 2 modification is the same as that of the Fig. 1 modification.

Figs. 3 and 4 illustrate a modification of the invention wherein the crank is attached to the drill stem for rotation at its upper end and is formed so as to permit lubrication of the outside of the crank or tool during insertion, motion through or rotation in the pipe to reduce friction and wear. Fig. 3 shows the lubricating modification employing bearings as described relative the Fig. 2 modiiication` and Fig. 4 shows the lubrication modification without the use of bearings. Referring first to Fig. 3, earth formation 30 has permeable formation 31 therein. Well; bore 32 extends below the permeable formation 31 and earth formation 30 and casing 33 is run therein below the permeable formation and has become stuck thereto byl differential pressure. Fig. 3 also shows the modification of the, method wherein the crank is run completely into. the obstructed area before rotation thereof is begun. In the lubrication modification, the crank 34 comprises a hollow tube bent, curved or crooked as at 34a, having an annulus 35 sealed as at 36 at its lower end. Perforations. 37 cut through the wall of the tubing 34. Threaded portion 38 of the crank 34 engages threaded portion 39 of drill stem 40., While the crank 34 is being forced through the casing 33 into the obstructed area, lubricating liquid or material may be forced out through the perforations 37 from the annulus 35 of the crank and the drill stem. This lubricating material may be used to reduce friction either in forcing thetool down the casing or in the rotation of the tool once it is positioned relative the stuck area of the pipe. When bearings 41 are employed at the contact points of the crank, as shown in Fig. 3, the tubing 34 is of slightly lesser outer diameter relative the inner diameter of the casing than a bearingless crank and the bearings 41 are of an outer diameter only slightly less than the inner diameter of the casing. Preferably, when bearings 41 are employed, perforations 37 are formed on each side of the bearings so that the bearings will not block ow of the lubricating material over the entire outer surface of the crank and all the bearings.

Referring to Fig. 4, the lubricating modification is shown without the bearings. Earth formation 42 has permeable formation 43 therein. Well bore 44 is drilled through the permeable formation and casing 45 is run below said formation. Hollow tubing 46 having an outer diameter only slightly less than the inner diameter of the casing and having crooked portion 46a is run into the stuck portion of the casing against the permeable formation 43. The drawing has cut off the lower portion o-f the crank but it is intended that the lower end thereof be sealed as in Fig. 3. Perforations 47 communicate with annulus 48 of the tubing. Threaded portion 49 of the upper end of the tubing is fastened to threaded portion 50 of drill stem 51. The lubricating material, as in the Fig. 3 modification, may be forced out of the perforations as the crank 46 is moved through the casing to be freed or when it is positioned ready for rotation therein. Fig. 5 shows the effect of rotation of the crank 46 in the casing as the crank is rotated. Since the Width of the bent portion of the crank is less than the diameter of the borehole of the well, the casing 45 (full and dotted lines) does not abrade or wear excessively against the well wall when the crank is rotated. Aside from the differences noted, the limitations and characteristics of the cranks in Figs. 3 and 4 are the same as those in Figs. 1 and 2 (depending on whether or not bearings are employed) as to strength, size, length, shape, operation, etc. Both the Fig. 3 and Fig. 4 modifications are shown run into the jammed length of the casing before rotation, but both may be set into rotation before freeing the pipe is begun. l

A variation of the operation in the drill stem attached modification (Figs. 1 4), lies in running the crank into V'the stuck portion of the pipe and then merely rotating the crank therein 180, whereby to tlex the pipe away from the wall once only. This variation materially reduces at the end of the drill stem.

Figs. 6 and 7 show the secondary modification of the i invention wherein the crank or length of metal is not iixed -wear on crank, drill stem and casing. Conventional well .practice easily measures and controls the crank rotation to the end of the drill stem to be lowered orforced or length of metal 57 has curved, deformed or crooked portion 57a and is of a strength or rigidity whereby to cause the pipe 55 through which it passes to deform to assume the shape of the tool. The diameter of the solid metal bar 57 is preferably only slightly less than that of the pipe through which it passes. The width of the deformed portion 57a is less than that of the surface casing, if any, and the well bore through which it passes. The top end S8 of the tool is of lesser diameter to permit the mounting of packers 59 and 60 thereon. Packer mounting thimbles 6I Iare fixed to the lesser diameter portion 58 of the tool and support the packers 59 and 60 against hydraulic pressure exerted thereon from above.

In operation of this modification of the invention, `the packers are merely mounted on the crank or tool 57, the tool inserted into the casing, and hydraulic pressure exerted therebehind to force the crank downwardly through the casing. The hydraulically driven crank relies entirely upon the deformation of the tool and the resultant deformation of the pipe as it passes therethrough to dislodge the pipe from its engagement with the wall. While the drill stem mounted cranks may be employed in this manner, rotation thereof is more effective. In Fig. 6, the lower end of the crank 57 is already passed through the jammed portion of the pipe and thus the pipe is shown -as partly freed from the differential pressure sealing. When the tool has been forced through the obstruction, it may be forced through any other lower obstructed area of the pipe to free it as desired. It is not possible to remove the tool from the pipe in this modification without removing the pipe from the hole, `and this is the preferred method of recovering it. However, if desired, the tool may be merely forced down below any production area and left in the pipe or blown out of the end of the pipe which is then recovered free of the tool. The Fig. 6 modification of the invention works well in all stuck pipe situations with the exception of certain key seat blocks. It is possible for a tool as shown in Fig. 6 to be forced through a certain type of key seat block without freeing the pipe from the Well wall. The modification of the packer mounting hydraulically driven form shown in Fig. 7 does not suffer from this defect. It should be noted that the tool in the Fig. 6 showing need not be solid all the way through but it should be sealed either at the upper or lower end to prevent flow of the hydraulic fluid therethrough.

Fig. 7 shows a spiral modification of the tool of Fig. 6. Earth formation 62 has permeable formation 63 therein. Well bore 64 extends through the permeable formation yand therebelow. Casing 65 has been run through and rbelow the permeable formation and is jammed thereat by differential pressure as at 66. To unstick lcasing 65 from its adhesion to permeable formation 63, rigid, casing deforming, spiral crank 66 having lesser diameter portion the casing by hydraulic pressure. The width of the spirals in the length or crank 66 is greater than the diameter of the casing 65 so that the casing is deformed as at 70a,

v71, 72 and y73 as the crank is forced therethrough. No YfInaYttei-.A.what the cause of the jamming or sticking of the pipe,V the forcing of the crank 66 through the obstruction will cause deformation of the pipe and exert the desired force thereon to free it from the cause of the sticking. -Other'than' the difference in shape, and a somewhat lesser farfeais the saine also.

It `should be understood that while the cylindrical form is preferred on all of the cranks or elements shown in ethe drawings and described in the specification, any desired form, triangular, square, hexagonal, etc., in cross section may be employed so long as the greatest diameter ofthecross-sectional form is not greater than the ,inside diameter of the pipe to be freed. The usefulness of the ,cylindrical form lies in its minimizing of friction and localized Wear on the pipe as it passes therethrough and is rotated therein.

From the foregoing it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove lset forth together with other advantages which are obvious and which are inherent to the structure and method.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope o-f the claims.

As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth is to be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, I claim:

1. Apparatus for flexing pipe positioned in a well bore comprising an elongate body of metal, said body having a greatest outer diameter less than the inner diameter of the pipe to be :flexed and a length substantially greater than the inner diameter of the said pipe, said body crooked within its length whereby to form a rigid working tool having an effective diameter between its extremities greater than the inner diameter of the pipe to be flexed, said body of substantially greater strength `and rigidity than the pipe to be exed, said body strength and rigidity sufficiently greater than that of the pipe to be tiexed whereby to flex the said pipe when the body is positioned therein and further ex the pipe when said body is moved or rotated therein.

2. Apparatus as in claim l wherein said body is cylindrical.

3. Apparatus as in claim l wherein said body has a circumferential friction bearing in the area of greatest displacement from the axis of the body.

4; Apparatus as in claim l wherein said body has circumferential friction bearings adjacent the ends of the crooked portion therein.

5. Apparatus as in claim l wherein said body has a circumferential friction bearing in the area of greatest displacement from the axis of the body and circumferential friction bearings adjacent the ends of the crooked portion thereof.

6. Apparatus as in claim 1 wherein said body is crooked centrally thereof and has essentially uniform curvature on either side of the central portion thereof.

7. Apparatus as in claim 1 including means to attach said body to a drill stem on one end thereof.

8. Apparatus as in claim l wherein said body has packing means at one end thereof whereby to permit the length to be forced through the pipe to be liexed hydraulically.

9. Apparatus as in claim 1 wherein said body is formed of a solid piece of metal.

9 10 10. Apparatus as in claim 1 wherein said body has 13. Apparatus as in claim 1 wherein the crooked pormeans to attach it to a drill stem on one end thereof and tion of the length is formed in spiral conguration.

comprises a hollow tube open at both ends thereof.

11. Apparatus as in claim 1 wherein said body is a Refr c Ctd' thlofth's t t hollow tube with one end sealed and the other end wlth 5 e en es l e m e e l pa en means to attach it to a drill stem and at least one UNITED STATES PATENTS opening in the side wall communicating with the an- 52,102 Witsil Jan. 16, 1866 nulus thereof intermediate the ends thereof. 1,699,087 Woodmansee et al Jan. l5, 1929 12. Apparatus as in claim 1 wherein the effective ydiam- 2,011,036 Colmerauer Aug. 13, 1935 eter of the crooked portion of the body is less than the 10 2,336,334 Zublin Dec. 7, 1943 smallest diameter of the well bore to be passed through 2,340,959 Harth Feb. 8, 1944 by the body. 2,730,176 Herbold Jan. 10, 1956