US3820612A

US3820612A - Method for lubricating an unsealed boring bit

Info

Publication number: US3820612A
Application number: US00295858A
Authority: US
Inventors: R Snyder; P Snyder
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-10-10
Filing date: 1972-10-10
Publication date: 1974-06-28
Anticipated expiration: 1991-06-28

Abstract

There is disclosed a method and apparatus for drilling in which air is circulated through a drilling stem to a subterranean drilling bit to assist the cutting action of the bit and in which water and a slight amount of certain organic additives are admixed with the air which is circulated through the drilling stem to the drilling bit. It has been found that water-soluble polyalkylene glycols, which are available under the trademarks Textilol and Ucon, as well as a synthetic sperm oil available under the trademark Nopco 14A, exhibit highly desirable properties for use as the organic additives. The apparatus for practice of the invention comprises a drilling rig with means to rotate a drilling stem and its dependent drilling bit and force the stem and bit downwardly into an earthen formation with means to circulate a gas stream, typically air, down the drilling stem and through passageways in the drilling bit to cool and lubricate its bearing surfaces. The gas is discharged into the well bore and passes upwardly about the drilling stem, carrying debris and dust for discharge from the well bore at the earth''s surface. The apparatus includes means for introducing a controlled flow of an aqueous suspension or solution of the aforedescribed organic additives into the gas stream.

Description

United States Patent [1 1 Snyder et a1.

[ ,lune 28, 1974 METHOD FOR LUBRICATING AN UNSEALED BORING BIT [76] lnventors: Raymond C. Snyder, 5131 Princeton, Westminster, Calif. 92684; Paul F. Snyder, 14281 Hacienda,1-1untington Beach, Calif. 92647 221 Filed: Oct. 10, 1972 [21] Appl. No.: 295,858

[52] U.S.-Cl. 175/70 [51] Int. Cl E21b 41/00 [58] Field of Search 175/67, 69, 70, 205, 212; 252/85 R [56] References Cited UNlTED STATES PATENTS 3,040,822 6/1962 Graham et al 175/70 3,094,175 6/1963 Jackson 175/69 3,150,085 9/1964 Mallory 252/85 3,419,092 12/1968 Elenburg 175/69 3,718,195 2/1973 Clements 1. 175/69 Primary Examiner-George H. Krizmanich Attorney, Agent, or Firm-Fulwilder, Patton, Rieber, Lee & Utecht [57] ABSTRACT There is disclosed a method and apparatus for drilling in which air is circulated through a drilling stem to a subterranean drilling bit to assist the cutting action of the bit and in which water and a slight amount of certain organic additives are admixed with the air which is circulated through the drilling stem to the drilling bit. It has been found that water-soluble polyalkylene glycols, which are available under the trademarks Textile] and Ucon, as well as a synthetic sperm oil available under the trademark Nopco 14A, exhibit highly desirable properties for use as the organic additives. The apparatus for practice of the invention comprises a drilling rig with means to rotate a drilling stem and its dependent drilling bit and force the stem and bit downwardly into an earthen formation with means to circulate a gas stream, typically air, down the drilling stem and through passageways in the drilling bit to cool and lubricate its bearing surfaces. The gas is discharged into the well bore and passes upwardly about the drilling stem, carrying debris and dust for discharge from the well bore at the earths surface. The apparatus includes means for introducing a controlled flow of an aqueous suspension or solution of the aforedescribed organic additives into the gas stream.

10 (Ilaims, 9 Drawing Figures 3 $351 may METHOD FOR LUBRICATING AN UNSEALED BORING BIT BACKGROUND OF THE INVENTION This invention relates to a method and apparatus for drilling bore holes and, in particular, to a method and apparatus using air or gas drilling.

Recent developments in drilling have employed a gas, such as air, under high pressure which is injected into a drill stem through orifices in the drilling bit and upwardly through the bore hole between the drill stem and the bore hole. The high pressure gas cools the drilling bit as it is discharged from the drill stem, through passageways in the drill bit and into the well bore. The gas also carries dust and debris from the drilling upwardly through the well bore t the earths surface. The discharge passageways in the drill bit are positioned such that the high pressure jetting of the gas from the drill bit also assists in jetting or blasting into the earthen formation, facilitating the cutting action of the drill bit.

Water or water vapor has been injected into the high pressure gas stream to assist in cooling of the bearing surfaces of the drill bit and to assist in settling of the dust formed by'the cutting action. A variety of additives have been employed to assist the action of the gas stream. Additives which have been employed are typically anionic, cationic or nonionic surfactants and phosphate esters which contribute antiwear and corrosion inhibition characteristics to the gas stream as well as promote emulsification or suspension of the debris and cuttings and thereby prevent dust formation. These materials generally have hydrophobic and hydrophilic portions. The hydrophobic portion is typically an aliphatic or aromatic hydrocarbyl group and the hydrophilic portion is typically a sulfate, sulfonate, carboxylate, amino or polyoxyethyl group.

SUMMARY l The invention comprises a method and apparatus for drilling with a gaseous. circulating fluid and, briefly, comprises means and a method for the controlled and metered introduction of certain organic additives and water into the gaseous circulation fluid used in drilling.

Water is injected into the gaseous fluid at a rate of approximately 0.5 to about gallons per thousand cubic feet of the gaseous circulation fluid. This water contains from about 0.1 to about 5 weight percent of certain organic additives. The organic additives which have been found to extend the lift of drill bits and improve the drilling operation to a significant degree are: polyalkylene glycols, which are marketed under trademark designations of Textilol and Ucon, as well as a synthetic sperm oil material marketed under trademark designation Nopco Patters 14A.

V The drilling bit which is used has rotating cutters supported by bearing means and sealed by packing which is typically a lithium base grease. The use of materials such as the polyalkylene glycols or sperm oil which have moderate to high solubilityfor lithium base grease was expected to result in washing or removing of the packing from the drill bit. Contrary to such expectations, it has been found that the additives described and herein do not have a tendency to remove the lithium base greases. and furthermore. substantially extend the surface life of a typical drill bit.

DESCRIPTION OF THE DRAWINGS FIG. I is a view of a portable drilling rig equipped for use of the invention;

FIG. 2 is a view along line 2--2 of FIG. I;

FIG. 3 is a view along line 33 of FIG. I;

FIG. 4 is a view of the king swivel and drive means employed in the drilling rig;

FIG. 5 is a view of the drilling apparatus with the drill stem in a bore hole;

FIG. 6 is a view on line 6-6 of FIG. 5;

FIG. 7 is a partial sectional view of a drill bit used in the invention;

FIG. 8 is a view of the lower end of a drill stem and drill bit in a bore hole; and

FIG. 9 is a view on line 9-9 of FIG. 8.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to FIG. I, the invention is illustrated as applied to a portable drilling rig. The drilling rig comprises a platform It) with a plurality of supporting Mounted on platform 10 is a compressed gas supply means which comprises an engine 18 that can be an electric motor or an internal combustion engine. The engine shaft bears drive means 20 which is linked by suitable means such as flexible belts or chains 19 to driven means 22 mounted on the shaft of gas compression means such as the reciprocating piston compressor 24. The compressor is a standard compressor capable of delivering from 600 to about 2400 cubic feet per minute of air compressed to a pressure from about 40 to about 300 psi. The compressor receives air at atmospheric pressure and delivers the compressed air to discharge manifold 26. Conduit 28 connected to the discharge manifold 26 extends rearwardly along platform It).

Also mounted on platform I0 is the system for supplying an aqueous medium containing metered and controlled amounts of certain organic additives. The supply system comprises a tank or vessel 30 with fill means 32 and a bottom draw off conduit 36. The latter conduit extends to the suction side of suitable pump means, e.g., centrifugal pump 36, which is driven by power means such as its own power supply or by motor 18. Water 33 is maintained in vessel 30 for use in the process. This can be potable water or brine, preferably it is water of relatively low solids and silt content. Another container or vessel 40, of substantially lesser capacity than vessel 30, is also mounted on platform 10, either directly or supported by vessel 30. This vessel has fill means and a bottom draw off conduit 42 which discharges into the water conduit 34 through valve 46. Valve 46 preferably has a valve member and seat means adapted for close regulation of flow therethrough. For this purpose, the valve member is preferably in the form of a long tapered cone on the valve stem with a mating seat means to provide a gradually expanding opening as the valve stem is turned. The valve is sized to provide a metered control of flow of fluid therethrough at flow rates of from 0.05 to about 0.5 gallons per minute. Flow rate means such as a flow-meter, not shown, or volumetric calibration marks on vessel 40 can be used to observe and set the flow rate of the organic additives.

At the rear extremity of platform is mounted the drilling mast in the form of a plurality of

vertical stand pipes

50, 52, 54 and 56. The bases of these stand pipes are fixedly secured to platform 10 and are spaced symmetrically about aperture 58 in the platform. The upper extremities of the stand pipes are secured together by rails such as 60 and a platform 62 which is supported by the stand pipes. Two

support anchors

64 and 66 are secured to the inboard upper corners of the mast and these conduits extend to the forward comers of platform 10 where they are fixedly secured to impart stability to the drilling mast.

cairigerfi eans 76'E sirppdrtedbythedflllifigmast and carries the drill stem 68, drill bit 70 with means for rotating the stem and for applying a downward thrust of from 7500 to about 75000 pounds to the drill stem and bit.

The drilling rig is illustrated in FIG. 1 with the drill stem 68 fully retracted so that drill bit 70 is supported above platform 10. Flexible conduits in the form of

hoses

72 and 74 extend, respectively, from water supply conduit 44 and compressed gas supply conduit 28 to suitable manifolding means carried by carriage means 76.

The carriage means 76 for supporting the drill stem is best illustrated in FIGS. 2 and 3. Referring to FIG. 3, the carriage means can be seen to comprise a platform 78 which bears guide means in the form of rollers 80 that are rotatably mounted at opposite corners of platform 78 by shafts 82. At least one roller 80 is provided to engage with each of the vertical stand pipes and the rollers 80 have a concave outer rim to mate with the arcuate periphery of the stand pipes.

The drilling mast also supports roller chain means 88 to one side of platform 78. The ends of chain 88 are secured to the platform by bolt means 84 and 86 in a manner described and illustrated in FIG. 6. The'roller sprocket chain 88 extends vertically along the height of the drilling mast and into a driven connection with drive means 90 and motor 92. Together, these elements comprise means for imparting a downward thrust to the drill stem and bit.

Platform 78 also carries motor means 94 and swivel support means in the form of king swivel 96. Together, these comprise means for imparting a rotational force to the drill stern and bit. Motor 94 is any suitable supply of motive power, typically an electric motor of from 50 to about 150 horsepower, preferably about 75 horsepower.

The motor and drive means for rotation of drill stem 68 is better shown in FIG. 4. In this illustration motor 94 is shown with a downwardly dependent drive shaft bearing a sprocket 96. The upper end of the drill stem assembly comprises conduit 98 which has means for removable attachment of a length of drill pipe and which has its upper end secured to driven sprocket 100. A suitable roller sprocket chain 102 extends between drive sprocket 96 and driven sprocket 100. Suitable bearing means, not illustrated, provide for rotatable support of conduit 98 and associated driven sprocket 100 on platform 78. The upper surface of driven sprocket 100 has a flat surface with a central aperature 101. Mounted above the upper surface of driven sprocket is plate 102 which has a circular groove 104 that extends about the periphery of aperture 101. Groove 104 serves as seat means for suitable packing or sealing means 106 so that when flange plate 102 is fixedly secured to platform 78, the upper surface of driven sprocket 100 is in sealed engagement to plate 102. Plate 102 bears tapped apertures for the mounting of the

conduits

108 and 110 which extend. respectively, to

flexible hoses

74 and 72 and thereby provide for manifolding of the high pressure aqueous medium and high pressure gas supply into the interior of drill stem 68.

Referring now to FIG. 5, the drill stem 68 is illustrated within well bore 112 with drill bit 70 at the base of this well bore and carriage 76 advanced to a lowered position on the drilling rig mast. In this operation, compressed air is introduced through hose 72, manifold conduit 110 and king swivel means comprising driven sprocket 100 and conduit 98, downwardly through the drill stem 68 to exit through discharge orifices in drill bit 70. The discharged gas flows upwardly through the annulus between the drill stem 68 and well bore 112 as illustrated by the arrows. This compressed air stream is admixed with an aqueous medium containing the organic additives supplied through hose 74 and conduit 108 to form a gaseous dispersion with the high pressure gas that flows downwardly through drill stem 68.

The carriage 76 is forced downwardly by roller chain 88 which is illustrated in FIG. 6. As shown, one end of the chain is afi'rxed to carriage 76 by suitable attachment means such as bolt 86. The roller chain is passed downwardly and is looped over idler sprocket 116 which is rotatably supported on cross bar 118 that is fixedly secured to the base of

stand pipes

52 and 54. The roller chain 88 is then passed upwardly and over drive sprocket 120 that is secured at the end of the shaft projecting from gear train means 90. The roller chain 88 is then passed downwardly and into fixed engagement with the platform 78 by attachment means 84. In this fashion, motor 92 can, through drive train 90 and drive sprocket 120, transmit a vertical force to car riage 76 to force the drill stem and drill bit 70 into an earthen formation or retract it therefrom.

The construction of the drill bit 70 is illustrated in FIG. 7. The drill bit is shown as comprising a cast body 122 with an upper neck or boss 124 that bears male threads for engagement in the threaded lower end of drill stem 68. Body 122 has a plurality, generally three, of downwardly dependent legs 126, one of which is shown in cross sectional view in FIG. 7. Each leg has a lower arcuate skirt and a downwardly facing circular boss 128. The outer peripheral surface of boss 128 bears a plurality of grooves such as the arcuate groove 132 and the more inwardly positioned, stepped groove 134. These grooves serve, respectively, as seat means for a spherical retainer and bearing means, e.g., ball bearings 136 and the annular packing means 138.

The boss 128 comprises shaft means for mounting of rotatable cutters 140. Each cutter comprises a wheel having a scalloped or toothed outer periphery with cutting teeth 142. The cutting wheels 140 are generally cup shaped with a hollow interior for fitting about boss 128. The inside peripheral surface of the interior of wheel 140 also bears an arcuate groove and a stepped bit contains a through pas sageway 125 and a pluralityof passageways which are cast or bored therein. These passageways comprise meansfor directing the gaseous suspension of waterand additives into contact with the bearing surfaces for the rotatable mounting of cutting wheels 140 on body 122. Each leg 126 of the bit has a passageway 144 which extends from open communication with the passageway 125 of bit 70 into open communication with a transverse passageway 146 that extends from the inboard face of boss 128. Cutting wheels 140 are mounted on bosses 128 with their inboard faces separated slightly from the inboard face of boss 128 to provide a radial flow passageway for fluids discharged from flow passageway 146. The fluids discharged into this radial flow passageway pass outwardly and into contact with spherical bearings 136, cooling these bearings and, when certain organic additives are present, lubricating the bearings andpreventing wear. The fluids flow past the bearings 136, through the packing 138 and about the outer periphery of skirt 130 of leg 126.

As previously mentioned, the interior of body 122 of bit 70 is hollow with a through passageway 125. Near the mid-portion of this body, the through passageway has an annular groove 150 and a circular plate, 152 with an annular rim 154 is seated in groove 150. Plate 152 has a plurality of radially disposed apertures 156 to per- 3 mit passage of the gaseous fluid and aqueous medium containing certain organic additives into the inside undersurface of the drill bit 70 as indicated by the solid arrowhead lines. The fluid passing through this portion of the drill bit is discharged downwardly at a high pres sure to assist in blasting or jetting into the earths formation, facilitating the cutting action of the drill bit.

FIG. 8 illustrates the base of the well bore 1 12 shown in FIG. 5. Drill stem 68 is shown extending downwardly through the well bore 112 with bit 70 in contact with the base of the well bore. The rotation of drill stem 68 by drive motor 94 rotates cutters 142 in contact with the formation, removing clay, rock, silt, etc. from the well bore as the drilling progresses. The high pressure fluids are discharged from the drill bit 70 as indicated by solid lines 160 and by solid lines 162, the latter lines indicating flow of gaseous fluid which has passed over the cutter bearings and cooled and lubricated these hearings. Dirt, debris and dust removed by the cutting action is suspended in the gaseous fluid which flows upwardly in the well bore and is discharged at the ground 7 surface.

- FIG. 9 illustrates the drill stem as it is co-axially positioned in well bore 112. The cutters 142 which flare outwardly at the'base of the drill bit 70 are shown in contact with the outer extremity of the base of the well bore. The flow of the high pressure fluid is also shown in

solid lines

162 and 160 indicating fluids which have, respectively, passed over the bearing surfaces of the cutter heads or been discharged directly into the face of the well bore through the central jets of the drill bit 70.

In a typical embodiment, the drilling stem is about 8 inches in diameter and feet in length. The outside diameter of the drilling bit is from 5% to about 17% inches in diameter. The drive motor 94 is 75 horsepower while the main engine 18 is approximately 800 horesepower and the vertical thrust motor 92 is about 100 horsepower. The drill stem is rotated at about 30 to 50 revolutions per minute and a down pressure of about 50,000 pounds is applied to the drill stem. Approximately 600 to 2400, preferably from 800 to 1500, cubic feet per minute of air is supplied to the interior of the drill stem and is compressed to a pressure of about 40 to about 300 psi. at the drill bit. The flow rate of water and organic additives is approximately 0.5 to 10, preferably about 0.8 to about 2 gallons per minute.

It has been found that the use of certain organic additives at concentrations from about 0.1 to about 5, preferably from about 1 to about 2 weight percent in the aqueous medium substantially improves the operation of the drilling rig. It has been found that these additives: (1) permit an increased footage of drilling; (2) markedly decrease the amount of dust discharged from the well bore; (3) substantially inhibit corrosion of metal parts in contact with the water; and (4) achieve a more consistent hole depth during operation. M

The materials which can be used as the organic additives for the improved operation of the drilling rig are various synthetic materials. One class of materials are the water-soluble polyalkylene glycols, e.g., polypropylene glycol, polybutylene glycol, etc. These materials are commercially available, e.g., the Ucon brand fluids available from Union Carbide Chemicals Co. and Textilol brand of fluids available from the Texilina Co. The materials are available with a wide variety of properties such as pour point and viscosity. To illustrate, the following materials are available fr om Union Carbide having properties listed in the following table:

TA BI .15

Viscosity Pour Specific index Viscosity saybolt seconds at: point, F. gravity (A.S.T.M. (A.S.T.M. UCON grade' 20/20C. D-567-53) 210F. 100F. 0F. D-97-47) LB- 0.963 82 35.5 65 1,240 LB-385 0.995 144 75.l H 385 21,600 35 LB-1715 1.003 134 258' 1715 142,000 -10 LB-70-X 0.970 78 36.1 70 1,510 65 LB-400-X 0.997 141 74.3 400 26,600 30 LBl800-X 1.007 133 260 1,800 174,000 5 50-HB-55 0.991 97 34.3 55 712 50-HB-660 1.052 144 660 30,700 30 50-l-lB-1500 1.063 781 5,100 330,000 t -20 75-1-1-450 1.092 143 79.3 450 35 75-1-l-1400 1.093 197 1,400 30 75-H-90,000 1.095 90,000 40 Any of the above-identified materials are suitable for use in the invention; those having the intermediate viscosities, e.g., from about 200 to about 2,000 Saybolt Seconds at 100F. are preferred.

Another suitable material which can be used in the invention as one of the certain organic additives is a substitute sperm oil which is available under the designation Nopco 14A, from the Potters Chemical Division of the Diamond Shamrock Corp.

The materials are useful at concentrations in the aqueous medium from about O.l to about 3 weight percent, preferably from about 1 to about 2 weight percent. When employed in the aqueous medium in the method described herein, such materials greatly improve the drilling operation. In specific applications, it has been found that the use of a polyalkylene glycol such as the Ucon brand fluids set forth in the preceding table achieves approximately 20 percent greater bearing life with a commercial drilling bit. The normal life of a bit was extended from 5000 feet to 6140 feet with approximately 2 weight percent of the aforementioned Ucon brand fluid. In another test, a concentration of 1.66 weight percent of the Potters 14A, substitute sperm oil. in water. resulted in a 61 percent increase in footage to a useful life of 8400 feet.

In addition to increasing the service life of drilling bits, the compositions also substantially decrease the amount of dust which is formed during the drilling, presumably by better encapsulation of the dust and soil particles. It has further been observed that a substantially reduced corrosion rate is achieved and that metal surfaces contacted by the aqueous medium have longer service life.

The addition of the aqueous composition containing the aforementioned synthetic organic additives to the high pressure air supply also permits more consistent hole depths because of the superior penetration of the bit and a reduced amount of cave-ins of the blasting hole bore which result from uneven or excessive penetration of the air and water stream about the perimeter of the blasting hole. By use of the additives, it has been possible to consistently penetrate to a depth of 55 feet with the drill stem without cave-in rather than the approximate 49 feet of depth possible without the additives. The resistance of the blasting hole to cave-ins is also reflected in ease of operation in removing the drill stem from the hole since undue precautions are not necessary to avoid cave-ins while the bit is being withdrawn from the well bore. 7

The invention has been described by reference to particularly illustrated and preferred embodiments. It

is not intended that the invention be unduly restricted by such specific illustration. lnsteacf it is intended that the invention be defined by the steps, reagents and means. and their obvious equivalents, set forth in the following claims.

We claim:

1. A method for the drilling of bores in earthen formations wherein a drill bit carried on the end of a drill stem is rotated and forced into' the earthen formation and a gas stream under a pressure of from under 40 to about 300 psi. is injected into the drill stem and discharged through passageways and orifices in said drilling bit to cool the bearing surfaces of said drilling bit and to suspend and remove dust and cuttings from the vicinity of said well bit. the improvement comprising:

the steps of adding to the gas stream from 0.5 to

about 10 gallons of an aqueous medium per thousand cubic feet of said gas; and

adding to said aqueous medium from 0.1 to about 5 weight percent of an additive selected from the class consisting of water-soluble, polyalkylene glycols and synthetic sperm oil. 2. The method of claim 1 wherein said additives have viscosities from 50 to about 90,000 universal Saybolt Seconds at 100F.

3. The method of claim 1 wherein said additives have a pour point from about to about 40F.

4. The method of claim 1 wherein said additive is a polyalkylene glycol.

5. The method of claim 1 wherein said additive is a synthetic sperm oil.

6. The method of claim 1 wherein said gas stream is circulated at a rate from 600 to about 2400 cubic fee per minute.

7. The method of claim 1 wherein said gas stream is circulated at a rate from about 800 to about 1500 cubic feet per minute.

8. A method for the drilling of bores in earthen formations comprising the following steps:

rotating a drill bit carried on the end of a drill stem and forcing it into the earthen formation;

injecting a gas stream under a pressure of from under 40 to about 300 psi. into the drill stem and discharging it through passageways and orifices in said drilling bit to cool the bearing surfaces of said drilling bit and to suspend and remove dust and cuttings from the vicinity of said well bit; and

adding to said gas stream from 0.1 to about 5 weight percent of an additive selected from the class consisting of water-soluble, polyalkylene glycols and synthetic sperm oil.

9. The method of claim 8 wherein said additives have viscosities from 50 to about 90,000 universal Saybolt Seconds at F.

10. The method of claim 8 wherein said additives have a pour point from about 85 to about 45F.

f STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. $820,612 D d I June 28, 1974 Inventor) Raymond C. Snyder and Paul F. Snyder It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the apec:alfiicatican, Column 1, line 58, delete "Nopoo Patters" and substitute therefor #51 Potters.---.

' m In the claims, in Column 8, line 54, delete "45F. and substitute therefor 40F.

Signed and sealed this 15th day of October 1974.

( E Attes t:

MCCOY M. GIBSON. R; Attesting Officer C MARSHALL DANN Commissioner of Patents USCOMM-DC 60376-P69 D \LS. GOVIINIIINI lnm'rma ornc: 19a 0-366-334 FORM PC4050 (1069)

Claims

2. The method of claim 1 wherein said additives have viscosities from 50 to about 90,000 universal Saybolt Seconds at 100*F.
3. The method of claim 1 wherein said additives have a pour point from about -85* to about 40*F.
4. The method of claim 1 wherein said additive is a polyalkylene glycol.
5. The method of claim 1 wherein said additive is a synthetic sperm oil.
6. The method of claim 1 wherein said gas stream is circulated at a rate from 600 to about 2400 cubic feet per minute.
7. The method of claim 1 wherein said gas stream is circulated at a rate from about 800 to about 1500 cubic feet per minute.
8. A method for the drilling of bores in earthen formations comprising the following steps: rotating a drill bit carried on the end of a drill stem and forcing it into the earthen formation; injecting a gas stream under a pressure of from under 40 to about 300 psi. into the drill stem and discharging it through passageways and orifices in said drilling bit to cool the bearing surfaces of said drilling bit and to suspend and remove dust and cuttings from the vicinity of said well bit; and adding to said gas stream from 0.1 to about 5 weight percent of an additive selected from the class consisting of water-soluble, polyalkylene glycols and synthetic sperm oil.
9. The method of claim 8 wherein said additives have viscosities from 50 to about 90,000 universal Saybolt Seconds at 100*F.
10. The method of claim 8 wherein said additives have a pour point from about -85* to about 45*F.