US2342253A

US2342253A - Method of and apparatus for testing loose geological formations

Info

Publication number: US2342253A
Application number: US309541A
Authority: US
Inventors: Cecil G Cooley
Original assignee: Individual
Current assignee: Individual
Priority date: 1939-12-16
Filing date: 1939-12-16
Publication date: 1944-02-22
Anticipated expiration: 1961-02-22

Description

Feb. 22, 1944. c. s. COOLEY 2,342,253

METHOD OF AND APPARATUS FOR TESTING LOOSE GEOLOGICAL FORMATIONS Filed Dec. 16, 1959 zz J7 0 I I 27 JI IN VENTOR.

ATTORNEYE.

Patented Feb. 22, 1944 UNITED STATE METHOD OI AND APPARATUS FOR TESTING LOOSE GEOLOGICAL FORMATIONS Cecil G. Cooley, Chillicothe, Mo. Application December 18, 193,, Serial No. 309,541.

. 9 Claims. ('01. 255-14) This'application is a continuation in part of, and a substitute for, my co-pending application Serial No. 114,818, filed December 8, 1936.

In the testing of sand and gravel deposits, or other loose geological formations-, two methods are in common use. Inone, an open well is dug into the deposit to be tested, this method having the disadvantages that piling is necessary it cavingoccurs and that water, if encountered, must be removed. In the other method, a pipe sim; ilar to a well casing is driven into the ground and the materials which come up inside the pipe are periodically bailed out. When the pipe encounters a boulder or other obstruction; it is necessary to interrupt the sampling process and the sinking of the pipe and to break up the boulder by a suitable tool inserted through the pipe.

It is the object of my invention to produce a process and apparatus for sampling gravel, sand,

or other loose geological formations and to do so infa manner which will be free from the objec- "tions inherent in the prior. sampling methods mentioned above. More specifically, it is my object to obtain by an uninterrupted process a continuous sample of loose material in'the form v the medium of a connecting rod l2 and crank I3.

rel (desirably having an internal diameter of at well-drilling rig, I rotate the core-barrel, preferably in timed relation to the frequency of the strokes of the drill rig at a rate which will move thecore-barrel through an angle equal to half that between adlacent cutting teeth for each 1 tend to prevent-the material within it from escaping when the core-barrel is raised.

The core-barrel is driven into the deposit being tested in the manner outlined above. When. the cutting element has reached the bottom of the formation to be tested, andnot before, the corebarrel is drawn from the ground. During the withdrawal operation the pipe or core-barrel is slowly rotated to reduce static friction and ob viate the necessity of jarring the core-barrel and thus disarranging the loose material constituting the core. The material within the core-barrel is elevated with it and represents an accurate cross section of the deposit through which the core-barrel is driven.

The accompanying drawing illustrates my invention: Fig. 1 is a side elevation of a well-drilling rig embodying my invention; Fig. 2 is a vertical section on an enlarged scale through the core-barrel and the means employed to rotate it; Fig. 3 is atop plan view .01 the barrel-rotating mechanism; and Fig. 4 is a view similar to Fig. 2, but illustrating the upper end of the core-barrel as ready to be drawn from the ground.

The well-drilling rig employed in practicing my invention may take difierent forms, and that illustrated in the drawing anddescribed herein is to be understood as merelyone example. The rig shown is portable in nature, being mounted on, an automotive truck Hi. In common with most drilling rigs, it embodies a pivoted beam' I I which is oscillated in a vertical plane through The beam it carries two sheaves l4 and I5, mounted respectively near the outer and inner ends of the beam. A cable l8, having one end secured to a winding drum l9, passes therefrom successively around the sheaves l5 and H and thence arounda sheave 20 at the top of a mast 21. During the process of driving the pipe, the free end of the cable l8 isattached to a driving rod 22 carrying a weight 23. It will be evident from this description that as the crank [3 is rotatedthe driving rod 22- and its associated weight 23 will be alternately raised and lowered.

A suitable-source of power, such asan internal combustion engine 25, is mounted on the truck III to drive the crank 13 and other moving parts or the apparatus.

Mounted in rearof the mast 2|, I provide a rotating table 21 conveniently supported from a suitable base 28 through an anti-friction bearing relative to the core-barrel. I also prefer to provide the core-barrel with some means which will.

29. The table 21 has an axial hole or opening clamp 3|, to the drill pipe or core-barrel 321.

I internal diameter or the core-barrel.

sleeve is free to slide vertically in the table 21, but the presence of the splines in the sleeve and the keyways in the table compels the sleeve, and

- the core-barrel 32, to rotate with the table.

presented cutting edges. At the: upper end of.

the shoe, its internal and external diameters correspond respectively to those ofthe core-barrel 32. At the lower end of the shoe, however, the bore is made slightly smaller than the internal diameter or the core-barrel, and from its lower end the bore flares upwardly gradually to the This insures that any object small enough to enter the lower end of the sleeve will not become wedged in the core-barrel and tends to prevent such material from dropping from the core-barrel when it is withdrawn. Moreover, because of the disarrangement incident to the cutting action, the material constituting the core will not infrequently possess a higher proportion of voids than it did in its original state and will thus ordinarily occupy a greater volume; and by constricting s g tly the boreof the shoe at the lower end thereof, the amount of material entering the core-barrel is reduced and the core thus prevented i'rom attaining a length materially greater than the depth to which the drill is sunk.

The core-barrel 32 is preferably made up of sections interconnected by screw-thread joints which are flush on both the inner and outersurfaces of the barrel, and the shoe 35 is connected to the lowermost of such sections through a similar joint. I have found it convenient to make the sections or the core-barrel 32 about eight inches in external diameten-about seven inches in internal diameter, and about six feet in length. At the lowerendof the shoe the diameter of the bore thereof may be in the neighborhood of six and one-half inches-or about 7% less than the internal diameter or the core-barrel.

The diameter of the core-barrel is of considerable importance for several reasons. There is always a possibility that the shoe will encounter squarely a rock or boulder which is slightly larger in diameter than the bore of the shoe and which might become wedged therein to be driven downwardly into the deposit ahead of the shoe, thus interfering with the cutting action, preventing material from entering the core barrel, and causing an inaccurate sample to be obtained. As the diameter or the core-barrel and of the shoebore is increased, the chances of the shoe engaga boulder of a size tobecome wedged :in the shoe-bore are correspondingly decreased; and

moreover, the larger the boulder wedged in the shoe-bore the greater will be the resistance it 'the core-barrel the greater its strength in pro- Portion to the i'orceawhich are imposed upon it in operation. In view of these considerations, 1

The-

prefer to employ a core-barrel of not less than live inches internal diameter.

For reasons set forth above, the internal di-' ameter of the shoe at its lower end is made slightli 1y smaller than the internal diameter of the corebarrel itself. In practice, it is found expedient to make the bore of the shoe at the-lower end thereof about to 10% less than the internal diameter or thecore-barrel. If the shoe-bore is materially larger than this, inadequate assurance against jamming of large particles within the core-barrel is provided and the core may tend to climb or to grow longer than the depth to which the core barrel is sunk; and if the shoe-bore is is made materially smaller than that indicated as expedient, resistance to progress of the drill is increased and the entrance of material into the core-barrel is restricted to such an extent that ple is to be taken. The shoe 35 and at least one section of the pipe or core-barrel 32 are connected together and inserted into the sleeve 3! which is then clamped to the pipe. To prevent injury to the threads at the upper end of the pipe, it is desirable to provide a suitable driving cap such as that indicated at 40 in Fig. 2. The driving rod 22 is then inserted into the cap and the upper'end of the pipe, and the drill rig is started, the winding drum IQ being so adjusted that the weight 23 will strike the driving cap 40 at the lower end oi. each stroke. The table 21 is operativeiy connected to the engine 25 to be rotated slowly as the pipe is driven, the table conveniently being formed with an annular series of bevel-gear teeth 42 meshing with a bevel-pinion 43 operatively connected, preferably through a change-speed transmission 44 and a rig which is rotated, like the crank 13, by power from the engine 25. L

As the drill rig operates, the pipe 32 is driven into the ground, while rotating slowly about its own axis as a result or the rotation of the table 21.. Ordinarily the table 21 rotates the Pipe 32 through .an angle equal to about half that between two' adjacent teeth 35 for each stroke of the driving rod 22; altho h, rotation at a ani'erent relative speed may sometimes be advisable. As the driving 0! the pipe 32 progresses, additional sections are added to it, the sleeve 3| being transferred to each new section as it is added.

When the pipe has entered the formation to the depth to be tested, the clamp 3| is loosened and the driving rod 22 and driving cap ll removed. Some means, such as the lifting cap I illustrated in Fig. 4, is attached to the upper end or the drill pipe, and an eye it in the cap is con-. nectedto about on the end or a lifting cable It which extends over a suitable sheave at the top oithemsstfl and-thencetoawindingdrumor Windlass-55. ZBy rotation 01' the winding drum 5!, the pipe 32 is withdrawn from the ground.

bringing with it all material which entered it as it was driven. Withdrawal of the pipe is facilitated if it is rotated or oscillated as it is elevated. To prevent the loss from the lower end or the core-barrel of material which has entered thereinto during the driving operation, I may provide some means tending to retain such material. as illustrated in the drawing, this means takes the form of an annular series of light leaf-springs Cl 7 secured at their lower ends to the inner surface drive chain 45, to some suitable shaft of the drill of the shoe3 5. upp r or free ends of the from below, as they are easily deflected outwardly against the inner surface of the shoe; but when the pipe is lifted some of any material tending to drop from the shoe will become wedged be- .tween the outer surface of the strips 50 and the loose material, partly because of excessive friction, partly because the continuous rotation disturbs the material and results in displacementswhich prevent the obtaining of an accurate sample, and partly because the loose material fills the spaces between the cutting teeth and interferes with their cutting action. My invention has an advantage over the process of inter-- mittent pipe-driving and bailing in that the sample obtained. is a continuous one for the entire depth and in that the cutting teeth will cut through any large boulders encountered.

I am also aware thatit has been proposed to employ core-drills, driven by combined percus-- sion and rotation, in producing generally horispring strips 60 are bent inwardly of the shoe,

as is clear from Fig.2. The strips 60 afford no material resistance to material entering the shoe zontal holes in solid rock. It is to be noted,

however, that the use of core drills in loose formations of gravel or similar material such as I contemplate, is materially different from the use of core drills in solid rock. For example, in solid rock the drill-shoe cuts clearance for the core-barrel and there is no problem of friction between the core barrel and the material which the drill is penetrating; whereas in loose formations-the material closes in behind hole as desired; whereas such operation is impossible in the drilling of loose material. Moreover, a solid-rock core consists of a single piece or of a comparativelysmall .number of pieces fitting rather closely within the core-barrel, and disarrangement of the core is therefore impossible; whereas to obtain an" accurate sample of a loose gravel formation, such as my inventionv keep a running record of the level of the top of the core as the pipe is'driven. This may be done by interrupting the drilling operation at regular intervals-say intervals of one foot in the descent of the pipe, and noting the height of be provided witha stroke-counter (not shown) and a record kept of the number of strokes required to drive the pipe through each foot of its formation during the drilling operation as to the character of the deposit being sampled but will also provide a basis for the elimination of errors which otherwise might arise as the result of vertical displacements of the core during the drilling operation. I

Core displacements which might result in error in interpreting the sample can arise from several causes. If the drill is cutting through a stratum of loose gravel having a substantial percentage of voids, some of the gravel in the path of the drill may be displaced laterally and not enter the drill with the result that the whole core will drop. 0n the-other hand, if the drill cuts through a boulder or stratum of solid rock the action'of the teeth 35 in disintegrating the formation will result in the. creation of voids which will cause the .core to be forced upwardly. After the pipe has been driven and withdrawn from the ground, the several pipe sections are removed and the contents of each examined either as .an entirety or in increments. The

running record of the height of the top of the core during thedrilling operation permits the depth of each core-increment to be accurately determined.

At least to some extent, the displacement of the core relative to the surrounding earth can be reduced by varying the relation between the frequency of the strokes of the drill rig and the speed of rotation of the table 21. Reducing the relative speed of the table tends to lower the core, while increasing it tends to raise the core. In taking advantage of this, I make a continuous observation of the height of the top of the core, as by means of a flexibletape-line provided at its lower end with a small weight 66 adapted to rest on top of the core. The driving cap 40 may have anv opening 61 in its wall .for the passage of the tape-line.

If, by reading the tape-line 6Q, it is found that l the core is rising relative to the surrounding .earth, the variable-"speed transmission 44 may be 0 adjusted to reduce the speed of the table. On the other hand, if the core is found to be dropping, the transmission 44 may be adjusted to increase the speed of the table.

I claim as myinvention 1. A machine of the type described, comprising a core barrel, 9. cutting element attached to the lower end of said core barrel and having an annular series of cutting teeth, mechanism for imparting blows to the upper end of said core barrel to drive it into the ground, and means 10i rotating said core barrel and operating said mechanism in timed'relation. said means being adjustable to vary the speed of pipe-rotation relative, to the speed of said blow-imparting mechanism.

-2. A process of sampling deposits of sand,

gravel, or other loose material which comprises driving a core barrel thereinto by intermittent blows, rotating the core barrel as it is driven,

0 varying the relative speed or core-barrel rotation the top of the core within the barrel, and with drawing the core barrel and the core it contains.

5 driving a core barrel approximately vertically the top of the core. If desired, the drill-rig may descent. Such a record "will not only give ini to maintain approximately constant the level of.

thereinto by intermittent blows. rotating the core barrelasitisdriven. periodicallymeasuringthe height oi'the top oi the core of loosematerial within the barrel, and tly withdrawing thecorebarrelandthelooumaterialitcmv' tains.

4.-A process of sampling deposits ot'sand.

ravel. or other loose material which comprises driving apipe forming a corebarrel approximately vertically thereinto', by intermittent downwardly directedbiows, rotating the core barrel as it is driven, continuing the blowsand rotation.

untllthedesireddepthtobetestedisattained. anchoring the core of loose material 4 against downward movement relative to the core barrel, removingthecorebarrelandcoreiromthe ground by a vertical movement, and supporting the surrounding loose material upon the exterior surface of the core barrel during the driving and removal of the core barrel.

5. A process of sampling deposits of sand.

the-ground tested by subjecting'it simultane ously to an upward pull and to a movement of rotation about its axis, and supporting the surrounding hose material upon the exterior surface of the core barrel during the driving and removal oi the core barrel.

6. A process of sampling deposits of sand, grave], or other loose material which comprises cussion an. elongated tubular core-barrel having an open lower endtoseparateirom theremainder 0! the loose deposit a cylindrical core, continuing the driving of the core-barrel while supporting the surrounding loose material thereby until the desired depth to be tested is attained. whereby to obtain within the core-barrels. core which corresponds in length substantially to the depth of the deposit to be sampled and the geological formation or which corresponds substantiallyinpositionandarrangement withthatoi such deposit, anchoring such core against downward movement relative to the core-barrel, and then simultaneously withdrawing the core-barrel and the core it contains by subjecting the corebarrel'to upward pull while rotating it about its axis.

8. -A process of sampling deposits of sand, gravel, or other loose material. comprising driving into the deposit by combined rotation and percussion an elongated tubular core-barrel. havins an open lower end to separate from the remainder or the loose deposit a cylindrical core,

. conflnuing the driving of the core-barrel while driving a' core barrel having an inside diameter a of at least five inches into the material in a substantially vertical direction. by vsubjecting it to v rotation and to intermittent downwardly directed blows until the desired depth is attained, where-' bytheinside oi thecorebarrelwillbefllledwith' a, core whose geological formation will correspondsubstantially in position and arrangement with that of the deposit tested. anchoring the core against downward movement in the core,

barrel, withdrawing the core barrel and its contained core, and supporting the surrounding loose material upon the exterior surface .0! the .core barrel during the driving and removal of the core barrel;

supporting the surrounding loose material thereby until the desired depth to be tested is attained, whereby to obtain within the core-barrel a core which corresponds in length substantially to the depth of the deposit to be sampled and the geological formation of which corresponds substantially in position and arrangement with thatof such deposit, anchoring such core against downward movement relative to the core-barrel. and then simultaneously withdrawing the corebarrel and the cure it contains.

9. A process of sampling deposits of sand, ravel, or other loose material, comprising presenting to an exposed faceot such deposit the toothed end of a coreebarrel having an internal diameter materially greater than the diameter of the particles oi whichsuch deposit is formed. rotating the core-barrel while subjecting it to percussion to displace laterally particles in contact with the toothed end of said core-barrel without substantial disintegration of said par- 7. A process of sampling deposits or sand,

gravel, or other loose materiahcomprising driving into the deposit by combined rotation and pore moval of the core barrel.

ticles, continuing such rotation and percussion to drive the core-barrel into. the deposit to the depth to be tested, anchoring loose material within the core-barrel against relative downward displacement, simultaneously withdrawing the core-' barrel and all the loose material which entered its lower end as it was driven, and supporting the surrounding loose material upon the exterior sur-' face oi the core barrel during the driving and reo. COOLEY.