US3375884A - Sonic method and apparatus for driving casings through earthen formations - Google Patents

Description

April 2, 1968 G. BODINE, JR 3,375,884

A. SONIC METHOD AND APPARATUS FOR DRIVING CASINGS THROUGH EARTHEN FORMATIONS 3 Sheets-Sheet 1 Filed Aug. 16, 1965 INVENTOR. ALBERT. Gr. BODIN 15,312.

I icy w A ril 2, 1968 A. G. BODINE. JR 3,375,884

SONIC METHOD AND APPARATUS FOR DRIVING CASINCTS THROUGH EARTHEN FORMATIONS INVENTOR. FI E- I ALBERT G. Booms, 3'52.

ATTORN EV A ril 2, 1968 A. c. BODINE, JR 3,375,384

SONIC METHOD AND APPARATUS FOR VING CASINGS THROUGH EAR'IHEN FORMA Filed Aug. 16, 1965 3 Sheets-Sheet 5 INVENTOR. 7 ALBERT G. Booms, Jra.

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ATTORNEY United States Patent 3,375,884 SONIC METHOD AND APPARATUS FOR DRIVING CASINGS THROUGH EARTHEN FORMATIONS Albert G. Bodine, Jr., 7877 Woodley Ave., Van Nuys, Calif. 91406 Filed Aug. 16, 1965, Ser. No. 479,868 9 Claims. (Cl. 175-22) ABSTRACT OF THE DISCLOSURE A first casing string is driven into an earthen formation by means of sonic energy which is applied to the casing to cause resonant standing wave vibration thereof. When this string has been driven to a predetermined maximum depth, a second smaller diameter casing string having a substantially greater length than the first string is placed in internal concentricity therewith to form a new driving member which is driven by means ofsonic energy applied thereto to cause resonant standing Wave vibration thereof. Additional casings of succeedingly smaller diameter and greater lengths are driven in like fashion until the desired depth is reached. The walls of casing members as they are driven are substantially sonically uncoupled from the opposing walls of the externally concentric adjacent casing member such that the Q of the vibration circuit is increased to make for higher sonic energyat the driving end of the casing.

This invention relates to a sonic method and apparatus for driving casings through earthen formations, and more particularly to such a method and apparatus particularly suitable for making very deep bores.

The utilization of acoustical energy in driving elongated members, such as piles and casings into the earth, is described in my Patent No. 2,975,846. In the technique described in this patent, a pile member is sonically vibrated by means of an orbiting mass oscillator to produce standing wave vibration of such pile member. The resultant high level sonic energy enables the pile to bore through the earthen formation in a highly efiicient fash- 101].

In making very deep bores, i.e., of the order of several thousands of feet, as in the driving of oil wells, the Wall friction between the great lengths of casingutilized and the surrounding earthen material poses a severe limitation on the efliciency of the system. Thus, such frictional eifects greatly lower therelfective 'Q of the acoustically vibrating system, severely limiting the amount of acoustical energy available at the lower end of the casingwhere the driving is being accomplished.

To facilitate the comprehension of this problem and the techniques utilized in the device of the invention to overcome same, it is helpful to analogize the acoustically vibrating circuit involved to an equivalent electrical circuit. This type of analogy is Well known to those skilled in the art and is described, for example, in chapter 12 of Sonics by Hueter and Bolt, published in 1955 by John Wiley and Sons. In such an analogy, force, F, is equated with electrical voltage, E; velocity of vibration, u, is equated with electrical current, i; mechanical compliance, C is equated with electrical capacitance, C mass, M, is equated with electrical inductance, L; mechanical resistance (friction), R isequated with electrical resistance, R; and mechanical impedance, 'Z is equated with electrical impedance, Z Thus, it can be shown thatif a member is elastically vibrated by means of an acoustical sinusoidal force, F, sin ml, to being equal to 271' times the frequencyof vibration, that 1 F Sin wt 3,3 75,884 Patented Apr. 2, 1968 Where wM is equal to l/wC a resonant condition exists, and the effective mechanical impedance, Z,,,, is equal to the mechanical resistance, R reactive impedance components wM and l/wC cancelling each other out. Under such a resonant condition, velocity of vibration, a, is at a maximum, effective power factor is unity, and energy is most efficiently delivered to a load to which the resonant system may be coupled. It is such a high efiiciency resonant condition that is preferably utilized in the technique and devices of this invention to achieve the desired end results.

Just as in electrical circuitry, maximum acoustical energy can be transferred from one circuit element to another where a good impedance match exists, i.e., where the two elements have like impedances. This fact becomes particularly significant in the method and apparatus of the instant invention where energy transfer from the penetrating end of the casing to the earthen formation is necessary to cause the disintegration of such formation in effecting the driving operation. By observation of Equation 1 it can be seen that the impedance, Z is high where the force, F is high, and velocity of vibration, u, is relatively low. Thus, in view of the high impedance characteristics of earthen formations, it is desirable that the penetrating end of the casing exhibit high impedance characteristics, i.e., that high force conditions exist at this point.

Also of particular significance in the instant invention is the attainment of high acoustical Q in the casing to markedly increase the etiiciency of the vibration thereof and to provide a maximum amount of cyclic energy for the driving operation. As for the equivalent electrical circuit, the Q of an acoustically vibrating circuit is defined as the sharpness of resonance thereof and is indicative of the ratio of the energy stored in each vibration cycle to the energy used in each cycle. Q is mathematically equated to the ratio between wM and wR Thus, the eifective Q of the acoustically vibrating circuit can be maximized to make for highly etlicient high amplitude vibration by minimizing the effective friction in the vibrating circuit, and/or maximizing the eflfective mass in such circuit.

In considering Equation 1 it should be kept in mind that this equation represents the total effective resistance, mass, and compliance in the acoustically vibrating circuit, and that these parameters are generally distributed throughout the system rather than being lumped in any one component or portion thereof.

The method and apparatus of this invention overcomes the shortcomings of prior art sonic boring techniques by providing means forsmaintaining the extended casing, in a high Q condition even where it has been run a considerable distance into the ground. Longer columns in fact often exhibit even higher Q characteristics than shorter ones by virtue of their greater mass. This end result is achieved by freeing the sides of all but the lowermost portions of the penetrating casing from contact with the earthen formation, thus considerably lowering the friction of the vibrating system. The very end .of the casing remains in contact with the earthen formation, thus forming a high frictional portion of the acoustical circuit having high impedance characteristics, whereby energy is effectively transferred at this point to the earthen formation to enhance the penetrating therethrough.

The desired end result is achieved in the device of the invention by utilizing a plurality of concentric casing strings of progressively smaller diameters, which are successively utilized as the driving members. As each concentric casing reaches its predetermined maximum depth, a new smaller diametered casing member is placed in internal concentricity therewith to form a new driving member, and when this new driving member has reached a predetermined penetration into the earth fornration, the first casing member is withdrawn. During actual driving of the second casing the outer casing is left in place, in this manner leaving the upper sides of the second member free from the surrounding earthen formation. In this manner, successive casing members having substantial portions of their longitudinal extents free from frictional contact with the earth formation, and thus having high Q characteristics, are utilized.

Sonic energy is coupled to each successive penetrating casing member from an orbiting mass oscillator, the vibrational output of which is tightly coupled to the casing. Acoustical energy is applied to the casing at a sonic frequency such as to set up a relatively large number of standing waves in such casing. The orbiting mass oscillator and the casing form a resonant system, such that the frequency of the output of the oscillator tends to lock in to maintain resonant vibration of the casing with changes in the parameters of the system. With a relatively long casing member having a high order of harmonic vibration at the vibration frequency, resonant frequencies for varying conditions are closely spaced making it relatively easy for the system to adjust itself to optimum resonant operation.

It is therefore an object of this invention to facilitate the sonic driving of casings through earthen formations.

It is a further object of this invention to improve the efficiency in the driving of casin g members through earthen formations.

It is still another object of this invention to minimize the frictional effects on a casing member in the making of deep bores through earthen formations.

It is still another object of this invention to substantially increase the Q of a casing member in a sonic drive system.

It is still a further object of this invention to provide maximum transfer of sonic energy from a sonic source to the penetrating end of an earth penetrating casing.

Other objects of this invention will become apparent from the following description taken in connection with the accompanying drawings of which,

FIGS. la-le are illustrations showing the technique of the invention,

FIG. 2 is an elevation view showing a preferred embodiment of the device of the invention in operation,

FIG. 3 is a view of the preferred embodiment of the device of the invention as taken along the plane indicated by 3-3 in FIG. 2,

FIG. 4 is an elevation view of the preferred embodiment of the device of the invention as taken along the plane indicated by 44 in FIG. 3,

FIG. 5 is a schematic view illustrating a drive mechanism which may be utilized to drive the orbiting mass oscillators of the device of the invention,

FIG. 6 is a plan view partly in cross section illustrating the clamping mechanism utilized in the preferred embodiment of the device of the invention, and

FIG. 7 is a cross sectional view as taken along the plane 7-7 indicated in FIG. 6.

Referring now to FIGS. la-le, the technique utilized in carrying out the invention is illustrated. As shown in FIG. 1a, a first casing 14 is driven into the ground 11 by means of sonic driving equipment as to be described in connection with FIGS. 2-6. When driving through relatively soft soil, to prevent earthen material from entering the inside of the casing, the end of casing 14 is capped off by a capping device 13, with the soil formerly occupying the space now occupied by the casing being compacted down and out into the adjacent layers of soil. Where the penetrating is being accomplished through harder earthen formations, the casing 14 is left open ended and the earth particles are then removed from the inner portion of the casing by hydraulic means well known to those skilled in the art. If so desired, a suitable coring tool may be utilized for such earth particle removal.

After casing 14 has reached its maximum practicable depth, a second casing 16 having a smaller diameter is inserted substantially in internal concentricity with casing 14. The sonic oscillator drive mechanism is removed from casing 14 and attached to casing 16, and casing 16 is then sonically .driven so that it drives into the earthen formation 11 as illustrated in FIG. lb. When casing 16 has reached its maximum practicable depth, casing 14 may be removed, leaving a spacing 19 having loose earth therein between the walls of casing 16 and the wall of earthen formation 11 as shown in FIG. 10. Such removal may be accomplished by clamping the sonic oscillator drive mechanism (not shown) to casing 14 and sonically driving the casing to loosen it from earthen formation 11 while it is being drawn upwardly by a lift mechanism (not shown).

A third casing 17, smaller in diameter than casing 16, is then inserted in internal concentricity with casing 16 and sonically driven by the output of the sonic oscillator in similar fashion to that of the other casings. Casing 17 is thus driven to its maximum practicable depth, as illustrated in FIG. 1d. Casing 16 can then be removed in the same fashion as described in connection with casing 14, to leave space 20 having loose earth therein between the walls of casing 17 and the earthen formation, as shown in FIG 1e. This procedure can be continued with succeeding smaller diameter casing sections until the desired depth is reached.

As can be seen, by virtue of this procedure, a large portion of the casing wall is freed from the earthen formation with only the lower portions of this wall being imbedded in the soil. The relative portion of the casing wall which is freed increases substantially as the depth of boring increases, as can be clearly seen by reference to FIG. Id. In this manner, the Q of the casing is made high by decreasing the wall friction thereof, such that very high energy is available at the penetrating portions where needed. Thus, whereas with prior art techniques, a substantial portion of the driving energy is dissipated in the upper earth with which the casing is in close contact, in the method of this invention, by virtue of the freeing of the upper casing portions, such dissipation of energy is eliminated and the casing is utilized as a high Q resonator which efiiciently transmits the energy to the penetrating end of the casing where it is utilized to maximum advantage.

Several other advantages accrue from the freeing of the casing walls. Firstly, the weight of the casing and its appended drive members is thereby free to provide a downward bias to aid in the driving operation. At the same time, the lower portion of the casing is held closely in the earth, thus preventing buckling and the generation of unwanted lateral parasitic vibrations. The high bias available by virtue of the free casing portions assures high acoustic force and impedance where the penetrating is being accomplished to assure maximum transfer of energy to the high impedance earthen formation. This highly efficient transfer of energy is especially significant where shaft driving at substantial depth into highly consolidated earth formations and where penetration becomes very difficult.

In clearing an earth boring, in applications such as oil well drilling, the technique of this invention permits tight penetration through problem areas such as salt domes and the like by virtue of the fact that the lower ends of the casing, where the driving is being accomplished, are tightly coupled to the earthen formation. This tight coupling is further enhanced by the sonic extraction of the upper casing section which tends to compact the earth around the inner remaining casing section. The utilization of a relatively long high Q casing section, which is resonantly vibrated at a high order harmonic frequency, facilitates the maintenance of an optimum resonant frequency for the column by virtue of the relatively close spacing of resonant frequencies with changes in system parameters. Thus, for example, a small change in the effective length of the casing will give rise to a new optimum resonant vibration frequency relatively close to the first.

If so desired, friction reducing means can be placed between the casing stringer members 14, 16 and 17. This may take the form of lubricating oil or may 'be in the form of low friction surfacing material such as a plastic film coated on the opposing surfaces of the casings.

Referring now to FIGS. 2-6, a preferred embodiment of the device of the invention is illustrated. Casing member 16 is tightly gripped by hydraulically actuated clamping jaws 20. Referring particularly to FIG. 6, a hydraulic drive fluid is fed to each of inner cylinders 30 through fluid inlets 27. Outer cylinder members 26 are slidably mounted on inner cylinders 30 which are fixedly attached to frame member 32. When hydraulic fluid is caused to pass into the cylinders 30 through inlets 27 from a hydraulic control device (not shown), outer cylinders 26 are urged away from frame 32 bringing clamping jaws 20 into tight clamping engagement with the wall of casing 16. It is to be noted that it is essential to the proper operation of the device of the invention that there be tight coupling between frame 32 and casing 16. At the same time, it is necessary that the clamping mechanism be readily releasable so that attachment can be made to a different casing member as the driving operation proceeds. These desired features of operation are effectively achieved by the hydraulic clamping mechanism shown.

Referring particularly to FIGS. 2 and 4, the acoustical drive signal is generated by means of orbiting mass oscil lator 35, which includes eight eccentric rotors 37a-37h which are rotatably mounted on frame 32. Rotors 37a-37h are driven by means of gas turbines 40 and 41, the output drives of which are coupled thereto by coupling shafts 72a72h respectively. Rotors 37a and 370 are driven in one direction, while rotors 37b and 37d are driven in opposite direction by the output of turbine 40, while rotors 37e and 3712 and rotors 37 and 37g are similarly driven in opposite directions by the output of turbine 41. The oppositely positioned rotors along each rotation axis, for example, rotors 37a, 37g and 37d, 372, etc., are driven in the same direction.

This rotational drive is achieved by means of a gear train for each turbine, as illustrated in FIG. 5. Thus, with the output shaft 45 of the turbine coupled to drive gar 49, gears 50 and 51 rotate in one direction while gears 52 and 53 are made to rotate in the opposite direction. The

drive shafts 56 and 57 for the rotors on one side (for example, 370 and 37d) are driven by gears 50 and 51, respectively, while the shafts 59 and 60 for the rotors on the opposite side (for example, 37a and 37c) are-driven by gears 52 and 53 respectively. The eccentric rotors 37a-37h are phased so that they act together to produce high mechanical vibration along the longitudinal axis of casing 16 while lateral vibrations are effectively cancelled out by virtue of the equal and opposite forces produced by the rotating members along the transverse axes. The orbiting mass oscillator tends to automatically adjust its output frequency so as to maintain resonant vibration of the casing with changes in the effective impedance thereof, such lock-in operation making for optimum elficiency in the utilization of the sonic energy.

The synchronous rotation of rotors positioned opposite each other along common rotation axes is assured by means of rotational couplers 70 which join together rotors 37a and 37g, 37b and 37h, 37d and 37e, and 370 and 377. Coupler members 70, which rotate with their associated rotors, have the additional function of counteracting the bending moments produced on the rotation shafts by the rotating eccentric masses. This is achieved by virtue of the fact that coupler members 70 are crescent shaped (see FIG. 7) and thus are eccentrically weighted so as to generate bending forces on the support shafts to counteract the bending moment produced thereon by the rotors. Oppositely positioned rotors 37a and 37g, 37b and 37h, 37d and 37e, and 370 and 37 f, are driven together in synchronous fashion by drive shafts 72a-72h respectively by virtue of the coupling provided therebetween by means of coupler members 70.

Support frame 74 is attached by means of a pulley mechanism 75 to an appropriate derrick device which can be utilized to raise and lower the frame as necessary in performing the boring operation.

The device and apparatus of this invention .thus provide highly effective means for transferring maximum sonic energy to the penetrating portion of a casing. This end result is achieved by freeing the sides of a substantial portion of the casing from the surrounding ground and by tightly coupling sonic energy to the top of the casing so that such energy is eificiently transferred to the penetrating casing portion.

While the method and apparatus of this invention has been described and illustrated in detail, it is to be clearly understood that this is intended by way of illustration and example only and is not to be taken by way of limitation, the spirit and scope of this invention being limited only by the terms of the following claims.

I claim:

1. A method fordriving a casing member into an earthen formation comprising the steps of sonically energizing a casing string to cause resonant elastic vibration thereof, said casing string having a larger diameter and a substantially shorter length than said casing member to cause said casing string to penetrate into said formation to almost its entire length, the inner portion of said casing string being kept substantially free of material,

placing said casing member within said casing string in internal concentricity therewith,

sonically energizing said casing member to set up resonant standing wave vibration thereof so as to cause said member to penetrate into said formation, the walls of said casing member opposite the walls of said string being kept substantially sonically uncoupled from said casing string and said earthen formation, and

sonically energizing said casing-string to cause resonant standing wave vibration thereof while drawing it upwardly to withdraw said string from the formation while said casing member is left in place.

2. A method for driving a first casing string through an earthen formation comprising driving ,a second casing string having a shorter length and greater diameter than said first casing string into said formation by sonically energizing said second casing string at one end thereof to cause resonant elastic vibration thereof as the other end thereof penetrates said formation, the inner portion of said second casing string being maintained substantially p y,

When said second casing string has almost entirely penetrated into said formation placing said first casing string within said second casing string substantially in internal concentricity therewith,

driving said first casing string into said formation by sonically energizing said first casing string to set up resonant standing wave vibration thereof to cause said first casing string to penetrate into said formation to substantially its entire length, the walls of said first casing string opposite the walls of said second string member being kept substantially uncoupled from said second string member and said earthen formation, and

sonically energizing said second casing string to cause resonant standing wave vibration thereof while drawing it upwardly to withdraw said second string from the formation while said first casing string is left in place.

3. The method as recited in claim 2 and further including the initial step of capping the penetrating ends of said casing strings to prevent the entry of earthen material into the inside portions thereof.

4. The method as recited in claim 2 wherein said casing strings are resonantly vibrated by means of an orbiting mass oscillator.

5. The method as recited in claim 4 wherein said orbiting mass oscillator is successively tightly coupled to the upper portion of each casing string wall with each casing string sonic energization step.

6. A device for penetrating through an earthen forma tion comprising a first casing member driven into said formation,

a second casing member having a smaller diameter and a greater length than said first casing member inserted within said first casing member, and

means for driving said second casing member into said formation comprising a frame member,

orbiting mass oscillator means mounted on said frame member for causing longitudinal resonant standing wave vibration of said second casing member, said orbiting mass oscillator means including a plurality of pairs of oppositely positioned eccentric rotors symmetrically mounted on said frame member,

means for connecting the rotors of each of said rotor pairs together,

means for rotatably driving said rotors to generate the longitudinal vibration, and

clamp means for tightly holding said second casing member to said frame member to provide close coupling of the vibrational output of said oscillator means to said second casing member, the walls of said second casing member being substantially sonically uncoupled from the opposing walls of said first casing member,

whereby said second casing member comprises a relatively high Q vibrating system with the penetrating end thereof transferring high sonic energy to said earthen formation to efficiently cause the fiuidization thereof.

7. The device as recited in claim 6 and further including friction reducing means located between the opposing walls of said first and second casing members.

8. In a device for driving through an earthen formation,

a first casing member driven into said formation,

a second casing member having a smaller diameter and a greater length than said first casing member inserted within said first casing member substantially in internal concentricity therewith, and

means for driving said second casing member into said formation comprising a frame member, orbiting mass oscillator means mounted on said frame member for causing longitudinal resonant standing wave vibration of said second casing member, the walls of said second casing member being substantially sonically uncoupled from the opposing walls of said first casing member, said orbiting mass oscillator means including a plurality of pairs of oppositely positioned eccentric rotors symmetrically mounted on said frame member, half of said rotor pairs being on one side of said second casing member and being driven in one direction, the other half of said rotor pairs being on a side of said second casing member opposite said one side thereof and being driven in a direction opposite said one direction, means for connecting the rotors of each of said rotor pairs together, means for rotatably driving said rotors to generate the longitudinal vibration, and means for holding said second casing member to said frame member to provide close coupling of the vibra tional output of said oscillator means to said second casing member, whereby said second casing member comprises a relatively high Q vibrating system with the boring end thereof transferring high sonic energy to said earthen formation to efficiently cause the fluidization thereof. 9. The device as recited in claim 8 and further including separate shaft coupling means for joining the rotors of each of said rotor pairs together to provide synchronous rotation thereof, each of said shaft coupling means comprising an eccentrically weighted mass for counteracting the bending moments produced by the associated rotors on their rotation shaft.

References Cited UNITED STATES PATENTS 739,268 9/1903 Shuman 6153.64 1,700,949 2/1929 Osborne 61-53.64 3,187,513 6/1965 Guild 17519 X 3,195,659 7/1965 Goodman 175-55 3,224,514 12/1965 Hornstein et a1. 175-55 3,280,924 10/1966 Povlovich 17555 CHARLES E. OCONNELL, Primary Examiner.

R. E. FAVREAU, Assistant Examiner.

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