US3168140A - Method and apparatus for sonic jarring with fluid drive - Google Patents

Description

Feb. 2, 1965 A. G. BODINE, JR 3,168,140

METHOD AND APPARATUS FOR SONIC JARRING WITH FLUID DRIVE 2 Sheets-Sheet 1 Original Filed Feb. 20, 1956 INVENTOR. ALBERT G. BODINE JR.

ATTORNEYS Feb. 2, 1965 A. G. BODINE, JR 3,168,140

METHOD AND APPARATUS FOR some JARRING WITH FLUID DRIVE Original Filed Feb. 20, 1956 2 Sheets-Sheet 2 FIG.4 F|G.5

22! INVENTOR.

AL B ERT G. BODINE JR.

ATTORNEYS United States Patent Ofifice 3,158,140 Patented Feb. 2, 1965 3,168,140 METHOD AND APPARATUS FOR SONIC JARRING WITH FLUID DRIVE Albert G. Bodine, Jr., Sherman Oaks, (Zalif. (7877 Woodley Ave., Van Nuys, Calif.)

Original application Feb. 20, 1956, Ser. No. 566,620, new Patent No. 2,972,380, dated Feb. 21, 1961. Divided and this application Dec. 22, 1960, Scr. No. 77,670

3 Claims. (Cl. 166-46) This invention relates generally to methods and apparatus'for loosening and/or pulling or removing elongated objects stuck or frozen by static friction in other objects, for example, pipe such as liners, casing, drill pipe, sucker rods and pump plungers, or other objects or fish which have become stuck by static friction in oil wells. It relates, in a still broader aspect, to longitudinal movement of elogna-ted members in a surrounding medium, and accordingly, is applicable not only to removal of stuck members, as pipe fast in a well bore, but to driving frictionally bound members downwardly in the well, and, in another application, to driving of piles into the earth.

One primary object of the invention is the provision of improved methods and apparatus for loosening and/ or moving frictionally stuck or bound members by transmitting acoustic waves therethrough under conditions of standing wave resonance, utilizing novel apparatus and procedures by which very tightly bound members may be readily broken loose and removed, or driven deeper.

This application is a division of my parent application, Serial No. 566,628, filed February 20, 1956, now Patent No. 2,972,380, entitled Acoustic Method for Moving Objects Held Tight Within a Surrounding Medium.

The invention provides for setting up in the elongated stuck object a resonant acoustic longitudinal standing wave of high amplitude, thereby causing a cyclic force in a longitudinal direction to be exerted by the object in the cement, or other surrounding holding medium, at the stuck point, as well as a cyclic elastic contraction and expansion of the object at the stuck point, which is at a velocity node of the standing wave. Impedance mismatch and phase differences between the object and the surrounding media in which the same is frozen prevent the surrounding media from contracting and expanding either in step with or to the same degree as that which the stuck region of the object may readily undergo under proper drive. Frictional resistance losses in any media also results in failure to transmit the alternate expansion and contraction from the stuck object to the media without material loss of amplitude. The lesser amplitude of the periodic contraction and expansion of the surrounding media means that the stuck object is clear of the media for a time during each contraction half cycle. Moreover, phase difference between the expansion and contraction cycles of the stuck object and the surrounding media means that the object is undergoing contraction during at least a part of the time that the surrounding media is undergoing its expansion halfcycle, with resulting still greater momentary clearance. In effect, the surrounding media stand back while the stuck object periodically contracts. Such action rapidly loosens the stuck or frozen object, and it may then be elevated by pulling upwardly on it. It is often desirable to pull upwardly on the object while it is undergoing its cyclic motion relative to the surrounding media, with the result that it moves upwardly by small increments as successive momentary clearances occur. In other cases, it is found preferable to permit the object, or a large longitudinal fraction thereof, to stand in compression, with the result that the object moves downward as it is loosened. After complete loosening, it

maybe readily elevated. A feature of the invention is the control of the tension and/or compression in the casing to accomplish most advantageous performance in any given case.

In order to achieve the above described loosening action, I have found it necessary to transmit relatively powerful acoustic waves down the frozen rods, pipe, fish, etc., to the site where the object is stuck in the cement, or other holding medium, whereby to develop cyclic forces working against and overcoming the holding strength of the cement or other holding medium on the stuck object, and to accomplish this, certain novel relationships between the source of the acoustic waves, the stuck object, and any supporting means for the equipment, have been found to be of prime importance. In this connection, I utilize the concept of mechanical impedance, which, in this case, signifies the ratio of total cyclic peak force to displacement velocity at any given point in the acoustic wave system. The stuck region of the object is a region of high impedance, being at a velocity node of the standing wave system, while the upper end of the object is a region of lower impedance, being at a velocity antinode of the standing wave system. The acoustic wave source may be a very powerful mechanical vibrator. Now, I have found that it is of utmost importance, if the necessary substantial power for tightly stuck jobs is to flow from the wave generator into the object in which the standing wave is to be developed, that the coupling between the generator and the object have an acoustic impedance which is of at least as high an order of magnitude as that of the upper end portion of the object at the coupling point. This impedance requirement may be met by use of a firm or rigid coupling means, for example serrated wedge slips, or mechanical clutch jaws, acting directly between the generator case or frame and the object. A low impedance coupling i.e., of lower order than that of the upper end of the object, involving, for instance, a flexible element, such as a common suspension cable, or the like, lacks the ability to transmit the high cyclic force that is available from the necessary high power generator, and apply it to the pipe. Thus a high impedance coupling, i.e., one of an impedance magnitude of an order comparable to that of the upper end portion of the object at the point Where the coupling is to be made thereto, is an absolute requisite, and is satisfied by any mechanical coupling device of suificiently high impedance. I sometimes prefer for this purpose a coupling device comprising well known serrated wedge slips rigidly connected with the generator and engaged directly with the object.

Also any supporting or suspension means for the acoustic wave generator must, I have found, have a relatively low mechanical impedance, and may be a flexible cable, desirably including a spring vibration-isolator, or other relatively compliant element, so as to prevent material transmission of vibratory power through such supporting or suspension means.

Still further, I have found it highly important to employ an acoustic wave generator which is operable at a resonant frequency of the stuck object, and one whose output impedance is comparable to the impedance of the object at the point of coupling thereto.

An important incident of the setting up of the described resonant acoustic standing wave in the pipe or other member to be loosened is an energy storage property inherent in resonant systems of the character in question. A large quantity of acoustic energy is periodically delivered to the vibrating pipe or rod string, stored therein, and periodically released therefrom so as to deliver large cyclic forces to the stuck point. The resonant pipe or rod string thus inherently functions as a large energy storage reservoir, giving the system a high Q factor, i.e., large flywheel effect, comparable to the tank circuit of an electric oscillator, and assuring large energy delivery and corresponding force application to the stuck region of the object to be loosened.

A particular form of my invention specifically covered in this divisional application embodies a fluid-driven mechanical wave generator or oscillator for setting up the sonic wave action in the elongated stuck object. My fluid drive system inherently possesses a certain degree of softness, flexibility or mushiness in its transmision characteristics that is unfortunately lacking in purely mechanical drives, which tend toward roughness in operation. The fluid driven oscillator is thus better able to run smoothly at the resonant frequency.

Particularly when the oscillator is in a down-hole loca tion, a fluid transmission column from ground surface to oscillator is of unique advantage. Such a long fluid column permits the down-hole oscillator to lock-in at various resonant frequencies with increased facility, in view of the yield or give in the fluid column. The oscillator is, in other words, because of the soft or flexible fluid link, fairly independent of flow irregularities of the fluid pump (usually a conventional piston mud pump) at the ground surface. As a matter of fact, assuming such a mud pump, and the use of drilling mud as a fluid drive medium, the alternating or reciprocating mud flow near the pump becomes substantially continuous flow at the down-hole oscillator. In addition, the fluid column affords a large energy storage reservoir, which tends toward stabilizing the operation ofthe oscillator, supplying always just the energy required for uniform oscillator operation.

An object of the invention is accordingly the provision of a fluid driven sonic jar.

The invention will be further understood from the following detailed description of a number of related illustrative embodiments, reference for this purpose being had to the accompanying drawings, in which:

FIG. 1 is a view, partly in elevation and partly in vertical medial section, showing an illustrative form of the invention adapted for loosening a string of well pumping sucker rods; 7

FIGS; 2 and 3 are sections on lines 2--2 and 33, respectively, FIG. 1.

FIG. 4 is an elevation of another embodiment of the invention;

FIG. 5 is a section taken on line 55 of FIG. 4;

FIG. 6 is a vertical medial section showing a modificaof FIG. 5; and

FIG. 7 is a section on line 77 of FIG. 6.

, FIGS. 13 illustrate an embodiment of the invention designed for the purpose of loosening an elongated elastic object or column, in this case an oil well sucker rod string and or pump plunger frozen in a well by sand or other conditions. The upper end portion of the sucker rod string 129, above well-head 130, known usually as the polished rod, is indicated at 131, and clamped thereto as by means of clamp 132, is an acoustic wave generator or oscillator 133. It will be understood that the sucker rod string 129 and deep well oil pump below the wellhead may be of any conventional type. Numeral 134 designates a hook understood tobe suspended by conventional derrick tackle, by, which it may be raised and lowered, and

this hook engages a bail 135 carrying the casing 136 of a low impediance spring isolator 136a.. A suspension rod 137 is reciprocable through an opening in the bottom of casing 136 and has at its upper end a head 139 supported on the upper end of coil spring 140 whose lower endiis supported on the lower end of casing 138. The lower end of rod 137 carries a socket 142 which receives the'upper extremity of rod .131, and this socket is equipped with a clamp 143 adapted to 'clamp r-od 131.rigid1y within the socket. As here shown, the socket may have a half round bore 144 adapted to snugly receivethe upperextremity of the polished rod 131, and with an enlarged half round bore 145 adapted to accommodate arcuate clampmem 4 ber 146 which engages the rod and clamps it by means. of screws 147.

The vibration generator 133 includes a housing 150 formed with a half round seat 151 (FIG. 3) adapted to engage the rod 131, and with a projecting arm 152 in which is mounted clamp screws 153 adapted to engage arcuate clamping member 154 engaging the rod 131 and clamping it tightly to its seat 151.

The generator housing 150 has a vertical fluid cylinder 155 formed with a bore 156 in which is fitted a linearly reciprocating piston 157 positioned between coil compression centering springs 158 bearing against caps 159 screwed into opposite ends of bore 156. The caps 159 are bored and threaded to receive air hose fittings 160 which are connected by air hoses 161 to' opposite ends of air cylinder 162. A piston 163 in cylinder 162 is reciprocated by connecting rod 164 driven from eccentric 165 on a shaft 166, which may be powered by and suitable at the other end thereof. On the opposite stroke of piston 163, the reverse takes place. Accordingly, piston 157 is caused to oscillate linearly within cylinder 156 between springs 158, which alternately elongate and contract to accommodate the action, and act to retard and stop the piston at the ends of the stroke.

The described linear oscillation of piston 157, whose mass acts on the end caps 159 of the cylinder through springs 158, results in alternating vertical reactive forces being exerted against the generator housing, and therefore on the sucker rod string to which it is rigidly clamped. The upper end portion of the sucker rod string is thereby vertically oscillated, and longitudinal acoustic waves are accordingly set up in the sucker rod string, and transmitted to the site where the string or pump plunger is frozen within the well. The suspension means as described comprises a low impedance support, the spring isolator preventing transmission of vibration energy to the hook and derrick tackle above. A biasing force or tension can be exerted in the sucker rod string, assuring efficient transmission of power from the generator to the rod string.

The acoustic waves, transmitted down the rod string as described above from the oscillator to the point where the rod string or pump plunger is stuck in the well, are reflected from the stuck (stationary) point and reflected back up the rod string. In terms of impedance'the point where the rod string or plunger is stuck is apoint of high mechanical impedance, and the cyclic stresses in the string or plunger are at maximum amplitude in that region, 1ongitudinal motion or displacement being minimized, or approaching zero. The prime mover driving the air piston 163 is then operated at a speed which, through the fluid drive system, reciprocates piston 157 of oscillator 133 at a frequency establishing in the rod string between the stuck point and said oscillator, a resonant acoustic standing wave of an odd number of quarter wavelengths, such as represented in FIG. 4 of my aforementioned Patent No. 2,972,380. The operator readily recognizes that he has set the prime mover todrive the. system at this condition of resonance by obvious and well-known physical manifestations of resonance, including large increases in amplitude of vibration with small variations in frequency, asin all vibratory systems operating at or approaching resonance.

It should be understood that when a resonant longitudinal standing wave is established in a column, which-is stuck or immobilized against longitudinal motion at a given point, a velocity node of the standing wave must necessarily occur at the stuck or immobilized point, and

that a cyclic longitudinally-directed force will be exerted in thecolumn, at the node, against the immobilizing medium. It should be understood that forces at a node at a free point in a column are opposed and dynamically balanced. When, however, a given column is held fast at an arbitrary point, the resonant standing wave set up in the column will have a node at the fast point, and, in general, the cyclic forces in the column on the acoustically free side of the fast point will not be dynamically balanced by like forces on. the other side thereof, but will be exerted against and opposed by the immobilizing medium. Additionally, as mentioned heretofore, the elastic column, in which a longitudinal standing wave is sustained, alternately elastically dilates and contracts at the velocity antinode in step with alternating compressive and tension phases of the wave in the column. This follows from a phenomenon generally referred to as Poissons Ratio, and consists in a radial dilation or contraction of an elastic column in response to compression or tension exerted in the column.

Returning to a consideration of FIGS. l-3, the longitudinally-directed cyclic forces thus exerted by the rod string or pump plunger on. the holding medium act to overcome the holding strength of the medium. The al ternating dilations and contractions of the spring act also to overcome the holdingstrength of the medium. In connection with the latter effect, i.e., alternating dilation and contraction of the string, owing to impedance mismatch between the string and the medium in which it is frozen, frictional losses between the members, and cyclic phase displacements, the cyclic contractions of the string are not followed up by like contractions of the medium in which the string has become frozen, and the bond is quickly broken.

A unique advantage in the system of FIGS. 1-3 is the softness or flexibility of oscillator drive afforded by the described fluid drive means, contributing toward ability of the oscillator to run smoothly and evenly at the resonant standing wave frequency desired to be established in the stuck column or rod string.

In FIGS. 4 and 5 is shown another embodiment of the invention, in this case characterized by a gyratory type of down-hole vibration generator or oscillator in a tool suspended in the well from a string of drill pipe and operated by down-hole turbine means motivated by fluid pumped down the drill string from the ground surface. Drilling mud fluid can be used, or crude oil, if available, or Water. Numeral 219 designates the lower end portion of a hollow drill stem suspended in well bore 211, and to the lower end of drill stem 210 is coupled the upper end of a section of heavy drill collar 212. Coupled to the lower end of the latter is a relatively slender and flexible pipe section 213, and pipe section 213 suspends the vibratory tool 214 by means of a coupling indicated at 214a. The tool 214 comprises a mandrel or hollow body 215 containing a turbine driven vibration generator 216.

The body or mandrel 215 is of good elastic material, such as steel, and relatively thick-walled excepting for an intermediate section 215a, wherein is formed an enlarged cavity 217 for accommodation of generator 216, and a lower end section 21517 which is formed with the socket 218 of an overshot grappling tool 219. The latter is conventionally shown with tapered extremity containing wedge slips 220 adapted to rigidly secure a fish 221.

The generator 216 comprises a cylindrical inertia roller 222 adapted to roll around a cylindric raceway 223 formed inside body section 215a. The lower end of roller 222 is vertically supported by the curved shoulders of ribs 224 formed inside body 214 at the lower end of the generator cavity 217, the interior walls of section 215a joining the thick-walled section below by a tapered surface 225 so as to provide adequate clearance for downward liquid flow from the chamber 217.

Tightly mounted in the upper part of chamber 217, above roller 222, are a plurality of vertically spaced turbine stators 230, and between these, on an axial stem 231 extending upwardly from roller 222, are tightly mounted a plurality of turbine rotors 232. Fluid pumped down through drill stein 210, inertia collar 212, flexible pipe 213 and into the upperend of body 215, is set into rotation in passing stators 230, and imparts rotation to rotors 232 and therefore to inertia roller 222. The roller accordingly rolls about raceway 223. It is of interest to note that, since the diameter of roller 222 is less than the diameter of its raceway 223 but is greater than the radius of the raceway, it will rotate on its axis at a lesser number of revolutions per second than its number of trips per second around the periphery of the raceway. Any slip between the surfaces of the roller and the raceway will affect this difference. It is the number of trips per second around the periphery of the raceway that determines the frequency of the generator.

The operation of the acoustic wave generator is as follows: The roller 222 rolling around the raceway 223 exerts on the body 215 a centrifugal force, and it will be seen that this force, rotating about the longitudinal axis of the body 215, elastically bends the surrounding portion of the body, moving it around in a gyratory path. The body 215 does not bodily rotate, but has a gyratory action which, upon analysis, will be seen to be the resultant of two perpendicular transverse linear harmonic vibrations in quadrature. A generator of this type is described more particularly in my Patent No. 2,960,314. As described in said patent, the elastic gyratory deformation of the portion of the body 215 surrounding the inertia roller 222 ispropagated by corresponding elastic waves traveling longitudinally along the body 215. These are transmitted to and along the fish 221 to the site where the latter is stuck in the well, where the wave is reflected back; and also, in the opposite direction, into and along the flexible pipe to the point of junction of the latter with the end of the heavy inertia collar 212, where the Wave is reflected back. Under such conditions, standing wave resonance is automatically developed along the body 215, the fish down to the stuck point, and the flexible pipe 213 up to the inertia collar 212, with a velocity antinode (region of maximum deformation amplitude) at the site of the generator, and velocity nodes at the point where the fish is stuck in the well, and at the junction of flexible pipe 213 with collar 212. The turbine driven roller is constrained by back reaction from this resonant system to roll around its raceway at the resonant frequency. The fluid drive system particularly accommodates this resonant frequency operation notwithstanding fluctuations in fluid pump operation. There may be additional nodes and antinodes in the system under certain conditions, but those described above are characteristic of the system.

The described resonant standing wave developed in the system with a velocity node at the side where the fish is stuck in the well, tends rapidly to loosen the fish. The gyratory wave action described, while propagated longitudinally of the tool string, takes place in a transverse plane. At the location where the fish is frozen in the well, where a velocity node of the wave occurs, the elastic stress magnitude is maximized, and gyratory motion minimized. Under these conditions, the fish is powerfully worked, and rapidly broken free of whatever has been holding it fast.

In FIGS. 6 and 7 is shown a modification of the system of FIGS. 4 and 5, being similar to that of FIGS. 4 and 5' excepting for employment of a modified type of gyratory acoustic wave generator. The tool 240 of FIGS. 6 and 7 may be considered a substitution for the tool 214 of FIGS. 4 and 5, and it will be understood that the device of FIG. 6 may be suspended from a drill string similar to that shown in FIG. 4, and may be equipped with an inertia collar and a flexible pipe section similar to the elements 212 and 213 of FIG. 4, the upper end of the tool 240 being understood to be coupled to the lower end of a flexible pipe such as 213. Further, the lower end portion of the tool 24%) may be formed with a grappling tool, similar in all respects to that provided at the lower end of the tool 214 of FIGS. 4 and 5.

With the understanding stated in the preceding para graph, the tool 240 comprises a hollow body 241, generally similar to the body 214 of FIG. 5, the lower portion of which is omitted from FIG. 6. The bore through the hollow body 241 has an enlarged cavity 242 in which is contained, at an annular spacing from the corresponding thin wall section of the body, a cylindrical case 243 for an unbalanced or eccentric rotor 244. This rotor has at the bottom a shaft 245 mounted in suitable bearings 246 placed in the lower end of casing 243, the lower end of the latter being closed by a'threaded closure disc. Rotor 244 has extending upwardly from its upper end a shaft 247, supported in a bearing 248 placed in the upper end of casing 243. The casing 243 has an upper end portion 249 formed with suitable packing 250 for shaft 247. The casing 243 is positioned within the thin wall portion of body 241 by means of ribs 252 extending inwardly from body 241 at the top, and similarly by ribs 253 at the bottom, the last mentioned ribs being also formed with shoulders at 254 for vertical support of the casing 243.

The rotor shaft 247 carres a plurality of axially spaced turbine rotors 258, and above each of these is a stator 259. The stators comprise rims 260 tightly seated in the bore of the body 241, and a multiplicity of radial vanes 261.

The upper extremity of rotor shaft 247, above the hydraulic turbine described in the preceding paragraph, is provided with an outboard bearing at 264, carried within a cup 265, and has an upwardly extending annular wall 268 forming a chamber 269 which is closed at the top by a flexible diaphragm 270.

Cap 267 has a central aperture 271, which communicates with a longitudinal passage 272 extending longitudinally through rotor 247 and opening at the bottom inside rotor case 243. The cup 265 has at the bottom a suitable packing 273 forming a fluid tight seal with shaft 247. Casing 243 is filled with oil and this oil extends upwardly through passageway 272 and aperture 271 into chamber 269. In the operation of the apparatus, the hol low pipe string carrying the device 240 is filled with driving fluid, and the hydraulic static head, of this fluid imposed on the flexible diaphragm 270 pressurizes the oil system and prevents leakage of the external driving fluid into the oil system through the various packings.

An inspection of FIG. 6 will reveal that a fluid passage has been formed downwardly through the tool 40 around the outside of the bearing cup 265 to the region of the turbine, and from the lower end of the turbine around the outside of rotor housing 243 to the downwardly extending bore below. The fluid is deflected by the stator vanes to drive the rotors of the turbine, and therefore the unbalanced inertia rotor 244. Rotation of the latter generates a centrifugal force, the reaction of which is transmitted through the rotor shafts, the rotor casing 243, and the supporting ribs 252 and 253 to the body 241. Apart from the detailed action of the specific gyratory acoustic wave generator of FIG; 6, the system is the same as that of FIGS. 4 and 5, and the description need not be repeated.

The several embodiments now disclosed are representative of fluid driven oscillators in acoustically vibratory jars, and will be seen to have the advantages stated in the introductory paragraphs of this specification.

The down-hole oscillator embodiments of FIGS. 4-7, with their long fluid column drive means, afford a large degree of softness or flexibility of oscillator drive, which permits smooth and even oscillator operation at the resonant frquency of thesystem, notwithstanding irregularities of fluid pumping action at the ground surface.

The invention has now been described through illustration of a number of illustrative embodiments; It is to be understood, of course, that these are merely illustrative of various different inventive forms in which the broad invention may be embodied, and are not to be considered as exhaustive of the complete range of equivalents coming within the broad scope of the appended claims.

I claim:

1. The method of moving a column system embodying a portion held fast in the earth and a portion extending therefrom which is acoustically free and in a condition to sustain a vibration wave pattern, that comprises: acoustically coupling a fluid-drive vibrator to said acoustically free portion of said column system at a point spaced from said held portion, and fluid driving said vibrator at a frequency which produces resonance of said column system and which establishes a vibration pattern with cyclic impulse force in said column system within the region of said held portion, said resonant frequency and said vibration pattern being established independently of minor irregularities in fluid drive effort by reason of inherent fluid drive flexibility.

2. The method of moving a column system embodying a portion held fast in the earth and a portion extending therefrom which is acoustically free and in a condition to sustain a vibration wave pattern, that comprises: acoustically coupling a fluid-drive vibrator to said acoustically free portion of said column system at a point spaced from said held portion, then applying a bias force to said column system tending to free said held portion thereof from the earth, and simultaneously fluid-driving said vibrator at a frequency which produces resonance of said column system and which establishes a vibration pattern with cyclic impulse force in said column system within the region of said held portion, whereby said bias force and said cyclic impulse force act in combination to move said column system against the holding resistance of the earth.

3. The method of moving a column system embodying a portion held fast in a bore in the earth deep below ground level, and a portion extending upwardly therefrom which is acoustically free and in a condition to sustain a vibration wave pattern, that comprises: lowering into said bore and acoustically coupling to said acoustically free portion of said column system at a point thereon spaced from said held portion, a fluid-drive vibrator, and pumping fluid from the ground level down said bore to said fluid-drive vibrator at a rate to drive said vibrator at a frequency which produces resonance of said column system and which establishes in said system a vibration pattern with cyclic impulse force in said column system in the region of said held portion thereof, said resonant frequency and said vibration pattern being established in dependently of minor irregularities in fluid-drive effort by reason of inherent fluid-drive flexibility.

References Cited in the file of this patent UNITED STATES PATENTS 2,667,932 Bodine Feb. 2, 1954 2,670,801 Sherborne Mar. 2, 1954 2,730,176 Herbold Jan. 10, 1956 2,808,887 Erwin Oct. 8, 1957 2,972,380 Bodine Feb. 21, 1961

Claims (1)

1. THE METHOD OF MOVING A COLUMN SYSTEM EMBODYING A PORTION HELD FAST IN THE EARTH AND A PORTION EXTENDING THEREFROM WHICH IS ACOUSTICALLY FREE AND IN A CONDITION TO SUSTAIN A VIBRATION WAVE PATTERN, THAT COMPRISES: ACOUSTICALLY COUPLING A FLUID-DRIVE VIBRATOR TO SAID ACOUSTICALLY FREE PORTION OF SAID COLUMN SYSTEM AT A POINT SPACED FROM SAID HELD PORTION, AND FLUID DRIVING SAID VIBRATOR AT A FREQUENCY WHICH PRODUCES RESONANCE OF SAID COLUMN SYSTEM AND WHICH ESTABLISHES A VIBRATION PATTERN WITH CYCLIC IMPULSE FORCE IN SAID COLUMN SYSTEM WITHIN THE REGION OF SAID HELD PORTION, SAID RESONANT FREQUENCY AND SAID VIBRATION PATTERN BEING ESTABLISHED INDEPENDENTLY OF MINOR IRREGULARITIES IN FLUID DRIVE EFFORT BY REASON OF INHERENT FLUID DRIVE FLEXIBILITY.

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