US3899033A

US3899033A - Pneumatic-kinetic drilling system

Info

Publication number: US3899033A
Application number: US430643A
Authority: US
Inventors: Huisen Allen T Van
Original assignee: Individual
Current assignee: Imperial Energy Corp
Priority date: 1974-01-03
Filing date: 1974-01-03
Publication date: 1975-08-12
Anticipated expiration: 1992-08-12

Abstract

A drilling system is disclosed which relies on the weight and reciprocating movement of the drill column to provide actuation and rotation of the drill bit at the bottom of the bore hole. A pneumatic power source located immediately above the bit is driven by raising the suspended drill column by means of draw works and releasing the column to convert the kinematic motion of the column into fluid power in the pneumatic power source. The compressed fluid enters a pneumatic chamber and causes rotation of the drill bit as it engages the sides and bottom of the bore hole. The system may also include a source of drilling fluid pumped from the surface through the drill column and pneumatic power source to the bottom of the well bore to return the cuttings to the surface. The pneumatic fluid after it drives the bit and is expanded may be mixed with the drilling fluid to provide a lift assist to the fluid as it is returned to the surface with the drill cuttings.

Description

United States atent [1 1 Van Huisen [451 Aug. 12, 1975 PNEUMATIC-KINETIC DRILLING SYSTEM [22] Filed: Jan. 3, 1974 [21] Appl. No.: 430,643

[76] Inventor:

[52] US. Cl. 175/97; 175/69; 175/103; 175/106; 175/107; 175/170 [51] Int. Cl. E21B 3/12; E21B 5/00 [58] Field of Search 175/93, 106, 107, 97, 100, l75/101,103, 170, 319

[56] References Cited UNITED STATES PATENTS 888,164 5/1908 Hardsocg 175/100 X 1747398 2/1930 Short 175/93 X 1,965.56 7/1934 Bannister... 175/103 2,635 852 4/1953 Snyder 175/93 1802.640 8/1957 Boucher et a1. 175/93 X 3047.079 7/1962 Wepsala 175/107 3,807,512 4/1974 Pogonowski et a1. 175/106 FOREIGN PATENTS OR APPLICATIONS 735 8]8 4/1943 Germany 175/93 Primary E.raminerDavid H. Brown Attorney, Agent, or Firm-Marvin E. Jacobs 5 7 1 ABSTRACT A drilling system is disclosed which relies on the weight and reciprocating movement of the drill column to provide actuation and rotation of the drill bit at the bottom of the bore hole. A pneumatic power source located immediately above the bit is driven by raising the suspended drill column by means of draw works and releasing the column to convert the kinematic motion of the column into fluid power in the pneumatic power source. The compressed fluid enters a pneumatic chamber and causes rotation of the drill bit as it engages the sides and bottom of the bore hole. The system may also include a source of drilling fluid pumped from the surface through the drill column and pneumatic power source to the bottom of the well bore to return the cuttings to the surface. The pneumatic fluid after it drives the bit and is expanded may be mixed with the drilling fluid to provide a lift assist to the fluid as it is returned to the surface with the drill cuttings.

19 Claims, 13 Drawing Figures PATENTEU AUG 1 2 I975 SHEET all! p I!!! lllrll lv- M KmJ PNEUMATIC-KINETIC DRILLING SYSTEM BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a new and improved drilling system and, more particularly, to a pneumatickinematic system utilizing the weight of the suspended drill column as a source of power for operation of a down-hole pneumatic unit for cutting and drilling action of a rotating drill bit. The invention was disclosed in Disclosure Document No. 013208 filed in the US. Pat. Office on Sept. 5, 1972.

2. Description of the Prior Art The conventional method of drilling a bore hole into the earths crust commences with site preparation after entry and water supply is realized. Site preparation usually includes construction of a concrete cellar over which a derrick and other ancillary drilling equipment is installed. At the derrick floor located above the concrete cellar, a rotary table is installed which rotates during the drilling process. A drilling bit is attached to a sub-collar which links it with the drill stem. The subcollar with the bit secured to it is suspended just below the rotary table and a drill collar is inserted and screwed tight to the bit and sub-collar with power tongs.

More lengths of heavy metal drill collar are added as required to provide sufficient weight followed by hollow drill stem in enough lengths to make up the proper length of drill string. The drill collar is subsequently attached to a square section of pipe known as a Kelly which fits into a square opening prepared through the rotary table. When power is applied to rotate the rotary table, the Kelly in the attached drill pipe and drilling bit simultaneously rotate pressing against the bore bottom to effect drilling.

The section of the Kelly extending above the rotary table is fastened to a swivel head which is held by a cable attached to a draw works permitting the lifting or lowering of the entire drill column by the draw works operator. During drilling a drilling mud, gas or fluid is pumped through hoses attached to the swivel head and passes into and through the drill column to cool the drill bit and return drill cuttings to the surface. In the annular space between the drill pipe and well casing, this mud additionally lubricates the drill bit, keeps the bore cool and stabilizes the walls of the bore. Especially in the case where the bore hole passes through porous or fissured ground, the drilling mud exudes into the openings until the larger particles deposit therein to form a thin, hard filter cake.

A drilling assembly of this type requires a separate source of power for pumping the circulating drilling mud, for the draw works which winds and unwinds the cable to control the tension and regulate the-weight through the drill string on the drilling bit and for rotating the turn table. Power is also required for lighting, pumping water and other auxiliary power needs. Several diesel engines which consume large amounts of diesel fuel are utilized to supply the energy requirements of the drilling rig. The size and height of the rig coupled with the amount of available power are principle factors which limit the depth to which drilling rigs can bore and the diameter of the bore hole. Other limiting factors are the weight of the drill column, the rotation of the drill column and the ability to pump the circulating fluid through the drill column to the bottom of the bore hole and back to the surface through the annulus. The deeper a bore hole is drilled, the more power is required to accomplish drilling. The deepest bore hole depth limitations are related to the tremendous weight of the lengthening drill pipe column which must be constructed of the strongest heavy gauge steel to sustain the tremendous torque and prevent twistoffs. Furthermore, a tremendous amount of power is required to pump drilling mud from great depths to the surface.

Moreover, as the depth of the bore hole increases, rotation of the drill column may cause a whipping of a portion of the rotating column against the side wall of the bore hole. The loss of metal from abrasion and grinding will weaken the drill pipe and make it more susceptible to twist-off by the torque forces being subjected to the long drill column.

As wells are drilled deeper and costs continue to rise, it becomes necessary to minimize damage to the hole and to the protective casing. It would be further desirable to minimize drill-pipe torque and the tensile strength requirements, quality and costs of the drill pipe. One approach satisfying many of these requirements has been provided by a variety of down-hole motors such as mud-drive turbines, positive displacement motors and electrically powered motors. The most promising of these types of motors has been the turbines and positive displacement mud motors, since mud is already used to remove cuttings from the well bore in most drilling operations. These systems have not found extended use since they are mainly useful in straight-hole drilling due to economic problems caused by bearings and fast wearing of bits. Horsepower input has been limiting and the penetration rate and duration of tool life have not been satisfactory. The down-hole motors have found use mainly in the drilling through diamond drillable soft formations such as shales, dolomites, some limestones and some sandstones. Another limiting factor is the mud-handling system since down-hole motors convert hydraulic horsepower to mechanical horsepower, the motor must be supplied with sufficient mud at a high enough rate to fit its specific requirements.

The environment of the hole is also important in considering the use of a down-hole motor since certain types of crudes are found to dissolve or swell the rubber coated portions of the down-hole motor system and a temperature of 300F is normally the limit for application of down-hole motors. Stabilization of the tool to prevent the bit from moving on bottom and creating an out of drift hole is also a factor in the use of these motors.

SUMMARY OF THE INVENTION The present invention in common with the downhole motor does not require rotation of the drill column. The drilling system of the invention doesnot require hydraulic horsepower delivered from the surface in high volume and pressure. In contrast, the drilling system of the invention is provided with a pneumatic or hydraulic power source located immediately above the bit and connected to the drill column. A source of air, gas or fluid such as drilling mud is delivered to the power source. The power source is operated by reciprocating the drill column by actuating and releasing the draw works. Thus, the present invention utilizes the great weight of the suspended drill column as a source of kinetic energy to compress gases or fluids for utilization as a power source available at the lower extremity of the bore hole. During operation of the down-hole pneumatic or hydraulic power chamber, the mechanical rotary output thereof is utilized to rotate the drill bit without necessitating rotation of the drill pipe column.

Other aspects of the invention relate to ejecting air or gas from the pneumatic chamber after being used to power the rotation of the bits into the drilling mud. The bubbles of gas serve to assist in raising the drilling mud through the annulus between the casing and the drill bit up to the surface. The drilling system of the invention eliminates the risk of twisting and breaking the drill bit from torque since surface rotation of the entire drill column is obviated. Thus, the invention permits use of lighter weight drill pipe in deep well drilling. The system of the invention further reduces the bulk weight of the rig and fuel consumption by utilizing the kinetic power potential of the heavy drill column. The system of the invention further permits drilling of deeper wells into the earths crust than has been possible or practical before by permitting the use of light-weight drill pipe and providing a drilling mud lift assist by the injection of the exhaust compressed gas or fluid into the circulating drillingfluid. Another feature of the invention relates to formation of spiral grooves on the drill column which creates a swirling effect to prevent buildup of filter cake on the casing. This is necessary in the system of the invention since the pipe stem does not rotate to provide the desired swirling flow of the mud to the surface.

These and many other attendant advantages of the invention will become apparent as the invention becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic and plan view of a first embodiment of a drilling system;

FIG. 2A is a front sectional view of the first embodiment showing the piston in lowered position;

FIG. 2B is a front sectional and plan view showing the piston in raised position;

FIG. 3 is a cross-sectional view taken along line 33 of FIG. 2B; I

FIG. 4 is a schematic view of a further embodiment;

FIG. 5A is an enlarged front view partly in section of the embodiment of FIG. 4 with the piston shown in raised position;

FIG. 53 illustrates the piston in lowered position and the expanders in extended position;

FIGL 6 is a cross-sectional view taken along line 66 of F IG. 5B;

FIG. 7 is a sectional view of an intermediate gas lift compression chamber;

FIG. 8 is a sectional view taken along line 88 of FIG. 7;

FIG. 9 is a front plan view of a multiple compressor embodiment;

FIG. 10 is a sectional and plan view of a further embodiment of a multiple compressor embodiment; and

FIG. 11 is a cross-sectional view taken along line 11-11 of FIG. 10.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIGS. l-3, the drilling system of the invention generally comprises a rotatable cutting bit 10 connected to fluidic rotary power source 12 which is in turn driven by a reciprocating pressure intensifier 14. The bit 10, power source 12 and intensifier 14 all form a down-hole motor unit 44 located at the lower end of the light-weight drill pipe 16. Reciprocating action is provided by a cable 18 connected to'the intensifier l4 and to the draw ,works 20 located on the surface. Reciprocation is suitably effected by cyclic actuation of the power unit22' by means of controller 24 to provide a cyclic lifting force and downward'release action on the cable 18. and appended structure.

The surface also contains conventional drilling structure and accessories such as a foundation or platform 26 over which is constructed a derrick 28, the top of which contains a crown pulley block 30 receiving the cable 18. I

The systemof the invention also includes a source of fluid .for delivery to the pressure intensifier 14. The fluidmay be gaseous or liquidfAs shown in FIG. 1, drilling mud conventionally used to remove the cuttings from the bottom 32 of the bore hole 34 may be utilized as the hydraulic fluid. The mud supply emanates from a mud supply 36 and is pumped by means of mud pump 38 which delivers a supply of drilling mud under pressure to the interior40 of the drill stem 16 through the gripping head 42. 1

Referring now to FIG- 2A, the mud flows through the interior of drill stem. 16 and as it reaches the combined down-hole drilling unit 44 it flows into a bypass line.46 which encircles the unit 44 and has an exit orifice 48 which applies a highpressure stream of mud onto the rotating cutting bits 10. The mud picks up the cuttings and rises through the annulus 50, optionally assisted by .draw pumps (not shown) and is recovered through outlet 52 where it is delivered to a mud pit (not shown) in which the cuttings are removed and the mud recycled to the mud supply 36.

The down-hole drilling-unit 44 contains a reciprocating piston 52 having a piston rod 54 attached to cable 18. The piston reciprocates within a piston chamber 56 formed by the outerwal1s58 of the unit 44. Port valves 60 are formed in the upper terminus of the chamber 56 which are closed during the uppermost travel of the piston 52. As the piston 52 falls when the tension on cable 18 is released, mud from annulus 50 will enter the port valve 60and'fill the chamber 56 above the top of the piston 52. Simultaneously as the piston falls it will force the mud contained within the chamber 56 below the piston head 52 out under high pressure through angularly directed exit ports 62. This high pressure 'mud will be directed against the vanes 63 of turbine rotor 64, the shaft 65 of which is rotatably mounted within a bearing 72 mounted in the lower wall of the piston chamber. The rotor 64 is in turn connected to a spindle gear 76 which rotates gears 78, 80 and 82 to transmit power to shaft 84 mounted within

bearings

86 and 88. The shaft 84 is in turn connected to the rotatable cutting bit 10. The mud continues past the rotors, around the gears to lubricate and cool the gears, and through ports 90 and 92 within bearing plates 94 and 96 and passes out through the apertures 98 within the casing of unit 44 to provide high pressure mud assisting the lift of the drilling mud to the mud pit through the annulus 50.

As shown in FIG. 28, as the piston 52 rises by retensioning the draw works, mud passes through unidirectional check valves 100 and fills the chamber 56 as the piston simultaneously forces mud out through the port valves 60 into the annular mud column.

The rotation of the turbine rotor 64 and bit may develop a torque in the drill pipe 16. The bit can be sta bilized and the torque minimized by attaching a plurality of centralizing spacers 110 which engage the wall 35 of bore hole 34 or casing 97 if the hole is cased. Usually three centralizers are sufficient in order to maximize the open annular passage for removing the drilling fluid. The torque could also be counteracted by attaching a kelly to the top of the drill pipe column and slowly rotating the column in a direction opposite to that of the developed torque.

The slow rotation of the drill column will also assist in the lift of the drilling fluid by inducing a swirling motion to the fluid. This swirling motion is further enhanced by applying a spiral band on the drill column, suitably by attaching a plurality of flanges 112 to the drill pipe segments. The flanges are preferably angled upwardly and the direction of the spiral should work in cooperation with rotation of the drill pipe column.

The illustrated reciprocating kinematic-hydraulic drilling system incorporates only one direct reciprocating movement and a resulting rotary movement and is simple and dependable to operate. The system utilizes the extensive weight of the suspended drill pipe column as a source of kinetic energy which is transferred to the fluid to drive the rotary hydraulic power source for the bit. Since the drill pipe column is not rotated at high speed, the risk of twisting and breaking the drill pipe from abrasion and torque is eliminated. Also, since the danger of twist-off from torque is eliminated, a lighter weight drill pipe may be utilized. The system of the invention reduces both rig weight and fuel consumption. Drilling to deeper depths becomes possible at lower energy and equipment costs. The drilling systemof the invention locates the rotational power at the bit, increases bit speed appreciably, reduces drill pipe wear, increases rate of penetration and provides straight hole drilling.

The lower part of the drive shaft may terminate in' a rotating bit sub of conventional construction having external or internal threads for releasibly securing a tool bit. The bit utilized may be a conventional bit utilized in either conventional rotary drilling or in modified high drill or turbo drill applications. The bit may include rotatable cutting wheels which may be free wheeling or mechanically or hydraulically powered to increase the churn type of cutting action of the drill.

The drilling system of the invention will provide an intermittent percussion and rotating cutting type of action. The motor size and dimensions will be selected to optimize the fluid volume and pressure attainable depending on the depth and other operating conditions. The drilling system of the invention will operate efficiently with all types of drilling fluids ranging from water to very heavy drilling muds including oil base muds, salt water muds, oil emulsion muds, clay base muds and high viscosity muds. Also muds with all types of lost circulating materials in concentrations to nine pounds per barrel can be utilized. The system can also operate with high-pressure gas or air. The weight or viscosity of the fluid has little effect on the tools performance. The weight of the drilling mud does, however, have a direct effect on the maximum pressure increase. Free solids in drilling fluids and especially sand can affect tool performance by accelerating bearing wear and wear of other motor elements. Sand content should be held to an absolute minimum, less than 1%.

The initiation of the reciprocating hydraulic cutting action cannot be accomplished until the initial depth of the hole is at least the length of the tool bit plus a length of drill column sufficient to provide the desired weight for drilling and for operation of the hydraulic motor. The initial bore hole may be formed by conventional churn or rotary techniques until the desired depth is achieved. The hydraulic piston and turbine section with attached bit is then lowered into the hole with the drill column and the mud. circulation started until the drill pipe column and the annulus are completely filled and the hydraulic cylinder is filled with mud. The reciprocating action-isthen started with mud circulation continued to remove the cuttings as the bit churns and cuts away the sides and bottom of the hole.

For drills having outside diameters of 5 to about 8 inches and tool lengths of about 20 to 25 feet, it is estimated that the flow rate of hydraulic fluid, supplied to the turbine .by the reciprocating pressure intensifer, should be about 200 to 500 gallons per minute to provide about 300 to 400 rpm bit speed having atorque ranging from about 200 to 1,000 foot/pounds. The flow rate of fluid supplied to the turbine is thus dependent upon both the frequency of reciprocation and velocity of the piston of the pressure intensifier. The kinematichydraulic drilling system can also be used successfully with gas or air as the rotary fluid. The volume of air required to operate the system is more than that required for drilling fluid but within the range of compressor capacity utilized for normal rotary air drilling methods. About 4.5 cubic feet per minute of air at 300 psi will provide the same work as 1 gallon per minute of drilling fluid. Suitable performance will be provided by pressures ranging between 300-400 psi. Because of the compressibility of air, the system is more sensitive to weight and will tend to stall out as the pressure differential reaches'over about 200 psi. Therefore, the tension of the column at the draw works has to be adjusted to determine the stall speed at the conditions of operation and is thereafter maintained above this level in order to provide the desired rotary action. A lubricant may be added to the air stream such as liquid soap, quar gum, gel or calcium stearate in order to lubricate the moving surfaces of the piston chamber and rotary impeller.

A pneumatic drilling system is illustrated in FIGS. 4-8. As shown in FIG. 4 in addition to the structure shown on the surface, the system further includes a compressor or pump 1 14 for supplying a pneumatic gas such as dried air through central air pipe 116. The piston rod 118 is surrounded by a spring 120 and which piston rod 118 is connected to an upper portion of a sleeve 122 which surrounds the piston chamber. The sleeve 122 is in turn connected to the drill pipe column 124 thereby enabling the lifting of the pipe column 124 by the cable and draw works 20 and gripping head 42. The centralizers 126 in this embodiment are fixedly connected to the sleeve 122 and to the outer wall 128 of the piston chamber. Thus, as the sleeve falls with the weight of the drill column 124, the centralizers will expand outwardly against the wall 130 of the bore hole and when the draw works raises the sleeve the piston 132 will raise and retract the centralizers 126. The uppermost travel of the piston will cause abutment against the upper wall 134 which through piston rod 118 and the top wall 136 of the sleeve will form a force transfer member supporting the whole drilling assembly in tension. This is analagous to the manner in which the drill stem 16 of the embodiment of FIGS. 1-3 is intermittently lifted. The piston rod 118 may be keyed to the piston rod aperture 138 as shown in FIG. 6 suitably by forming the rod with an angular surface such as a diamond or other polygonal cross section so as to minimize torque transfer to the drill column 124.

The air line 116 may be bypassed to the lower end of the chamber where it selectively feeds air into chamber 142 when check valve 144 is open during the up stroke of the piston 132. The mud is delivered through the annular portion 146 of the drill column and also is bypassed through line 148 to a terminus 150 applying its stream of drilling fluid to the rotatable cutting bit 10.

When the draw works releases the tension on the drill column 124, the sleeve 122 falls, the centralizers 126 expand and bind to the wall and the piston 132 drops compressing the air and expelling it at high pressure and volume through the outlet valve 152 and onto the rotor to drive the drill bit as explained above. The air exhausts through outlet ports 154 mixes with the mud and serves to assist in the lifting of the mud to the surface. As the tension is relieved, the spring 120 tends to return the piston rod 118 to its upper most limit while air enters through valves 144 and fills the piston chamber 142. The cycle is then repeated to provide another session of drilling.

Additional mud lifting assist is provided by including a plurality of gas compression chambers along the drill pipe string 124. As shown in FIGS. 7 and 8, the compression chambers 150 can take the form of a slidably mounted annular member 152 disposed over a section 155 of the drill pipe. Each annular member encloses a flanged disc 156 attached to the outer surface of the pipe 155 which acts as a piston on reciprocal movement of the drill pipe 155. A set of three expanders 158 attaches the annular member 152 to the drill pipe 155.

A first set of inlet valves 160 are provided on the drill pipe 154 adjacent the bottom of the piston chamber 162 and opposite a first set of outlet valves 164 provided on the outside wall 166 of the member 152. Another set of air inlet valves 168 are provided on the drill pipe 155 near the top of the chamber 152 opposite a second set of air outlet valves 170.

As the drill pipe string 124 is released and falls, piston 156 will fall forcing air out through valves 164 into the annulus 172 containing a column of rising drilling mud aiding in lifting it to the surface. The expanders 158 will be forced outwardly and will engage the casing 174. As the piston 156 falls, valve 168 will fill the chamber 162 with another charge of air. On the upward movement of the drill pipe 124, piston 156 will force this charge of air out through valves 170 while the chamber 162 below the piston 156 is being recharged with air through inlet valves 160.

In another embodiment of the multiple air compressor lift assist shown in FIG. 9, the multiple compressors are formed by means of telescoping, collapsible drill pipe segments. For example, drill pipe segment 180 may terminate in a plate piston 182 having a slightly larger diameter than the segment. The next segment having an upper lip 184 is slidably mounted over the piston 182. Flange stop 186 and seal plate 188 are disposed equidistant from the piston 182. The piston 182 and seal plate 188 are apertured to slidingly and sealingly receive the mud conduit 190 and air pipe 192. Outlet valved orifices 194 are provided immediately above stop plate 188 and an air inlet valve 196 is connected to air pipe 192 within the compression chamber 198 formed between the piston 182 and the stop plate 188.

As the tension of the drill pipe is released, the pipe will fall and as piston 182 falls it will compress the air within the chamber 198 and force it out through orifices 194 into the rising mud column within the annulus 200. A further compression chamber 202 is formed by pipe segment 204 which slidingly rides over segment 206 when the pipe string is dropped. The air between piston 208 and plate 210 will be compressed and ejected through outlet orifices 212.

A further embodiment of the invention in which the collapsible sleeve compressor is housed within the drill collar portion of the drilling system and in which the drilling mud supply is passed through directly to the rotating drill bit is illustrated in FIGS. 10 and 11. As shown in the drawings, the drill collar 300 is connected to the last segment 302 of drill pipe in a manner to prevent rotation. For example, the drill pipe 302 suitably contains key members 304 which engage into slots 306 provided in the upper end of the drill drill collar 300. An air line 308 extends throughout the drill pipe train and is connected to the inlet valve 310 disposed on the upper surface 312 of the sleeve member 314.

The mud line 316 is slidably and sealingly mounted through the top member 312 of the sleeve 314 and the bottom member 318 which then forms the piston for compression chamber 320. The mud line 316 also extends through the pneumatic rotating motor 322 which is rotatably mounted within the drill collar 300 by means of bearings 324. The mud pipe 316 further extends through the cylindrical shaft 326 to which the rotating cutting bit 328 is attached. The mud from line 316 is then forced through passages 330 within the cutting bit 328 and lubricates and cools the rotating cutting heels 332 before injection onto the bottom of the holes to pick up the cuttings for return to the surface.

The air from the pneumatic motor 322 leaves the motor through passages 334 in the cylinder member 326 and mixes with the mud as it rises through the annulus. The motor and compressor assembly is secured within the drill collar by means of locking mechanism 336 which is threadably attached to the collar 300 suitably by threads reversed to the direction of rotation.

The sleeve member 314 forms an auxiliary or ancillary air storage chamber 337. As the drill stem 302 falls, the sleeve 314 and piston 318 will fall compressing the air within chamber 320 and forcing it out through orifices 339 onto the blades of the pneumatic turbine rotor 322. As the sleeve falls, air is injected through line 308 through valve 310 into the chamber 337. As the lift stroke of the reciprocating action proceeds, a vacuum is created in chamber 320 drawing into the chamber air from chamber 337 through the valves 340.

The drilling penetration rate is a function of the weight on the bit at percussive impact and the rotary speed of the bit. The speed can be controlled by controlling the tension on the draw works and/or controlling the initial air pressure delivered to the compression chamber by means of the setting on the delivery compressor on the surface. Recommended bit weights for small bore holes range from 1,000 to 8,000 lbs. per inch of bit diameter. The mud must be provided in sufficient volume to cool and lubricate the parts and to remove the cuttings from the hole. Sufflcient pressure of mud must be provided at the bit face so that the cuttings can be cleared from the rolling cutters by the fluid jets. The circulation of the drilling fluid may be practiced in an intermittent manner until an optimum wall cake is formed to control water loss through porous strata and to prevent slaking or swelling of clays or clay shales exposed to water. The variable tension can be controlled by a clutch setting at the draw works. Reciprocation could also be provided by a reversible engine, a walking beam arrangement or the disposition of a rotating cam member onto the cables connecting the draw works to the drill pipe train.

There are four general drilling methods capable of boring large diameter holes (over 3 feet internal diameter), ie (1) churn drilling, (2) auger drilling, (3) core drilling, and (4) rotary drilling. Rotary drilling is the most effective and efficient technique for this purpose. Large diameter holes are needed for emplacement of explosive charges and for emplacing large diameter down-hole heat exchangers for geothermal recovery systems as disclosed in my prior U.S. Pat. Nos. 3,470,943, 3,521,699 and 3,765,477.

The down-hole pneumatic or hydraulic motor of the invention is readily adaptable to rotary drilling equipment and may be utilized in the same applications with minor modifications in the equipment, mainly elimination of the rotary table and swivel. The big hole drill rig is similar to ordinary rigs and includes the substructure, draw-works, prime-movers, mast and block and tackle. The draw-works input horsepower for a stationary rig for drilling a 48 to 66 inch diameter hole to a depth of 2,000 to 2,500 feet is from 1375 to 1625.

The drill string or in-hole components consist of the bit, drill collar including the down-hole motor and fluidic drive assembly and the drill pipe. The rolling cutter bit is the preferred tool for nearly all subsurface materials.

What is claimed is:

l. A fluidic-kinetic drilling system comprising in combination:

a downhole assembly comprising:

a rotatable drilling bit; fluidic means for rotating the drilling bit; a fluidic power source means responsive to kinetic reciprocation for actuating the fluidic means; suspending means extending from the surface for suspending the downhole assembly adjacent the bottom of a bore hole; and

means connected to the suspending means for reciprocating the fluidic power source means.

2. A system according to claim 1 in which said downhole assembly is received within a drilling collar.

3. A system according to claim 1 further including fluid supply means extending from the surface to the fluidic power source means for delivering power fluid thereto.

4. A system according to claim 3 in which the sus pending means comprises a series of connected pipe sections forming a drill column and said fluid supply means is received within said drill column.

5. A system according to claim 4 further including means connected to the outside surface of the drill column for inducing a swirling motion in the rising mud column.

6. A system according to claim 5 in which the swirling means includes a plurality of angled flanges connected to said drill column.

7. A system according to claim 5 in which the drill column includes a plurality of reciprocably actuated compression chambers, means for delivering gas to said chambers and means for exhausting compressed gas therefrom into the rising mud column to assist the lift thereof.

8. A system according to claim 3 further including means for delivering drilling mud adjacent the bottom of the bore hole and establishing an upward swirling of drilling mud thereby providing means for assisting in circulating drilling fluid from the surface to the bottom of the bore hole and back to the surface.

9. A system according to claim 8 in which said drilling fluid is utilized as the power fluid and the circulating means encircles said power source means.

10. A system according to claim 9 further including fluid pass-through means extending through the rotating means and drilling bit for receiving the power fluid from the power means.

1 1. A system according to claim 8 in which the power fluid is a compressible gas and said rotating means includes a pneumatic rotor.

12. A system according to claim 11 further including means for expelling the exhaust gas from the pneumatic rotor into the rising drilling mud to assist the lift thereof.

13. A system according to claim 3 in which the fluidic power source means includes a fluid compression chamber.

14. A system according to claim 13 in which said compression chamber includes a piston chamber and a piston.

15. A system according to claim 14 in which the chamber includes a pair of fluid inlets and outlets on each side of the piston to form a double-acting piston chamber.

16. A system according to claim 14 in which the fluid compression chamber includes a top member having a keyed opening and a correspondingly key-shaped piston rod received therein to prevent rotation of said chamber.

17. A system according to claim 14 in which the compression chamber includes an outer sleeve member slidably mounted on an inner member.

18. A system according to claim 17 further including expandable members connected to said sleeves during relative movement thereof.

19. A system according to claim 18 in which said expandable members comprise at least three metal members, each connected to said inner and outer sleeves.

Claims

1. A fluidic-kinetic drilling system comprising in combination: a downhole assembly comprising: a rotatable drilling bit; fluidic means for rotating the drilling bit; a fluidic power source means responsive to kinetic reciprocation for actuating the fluidic means; suspending means extending from the surface for suspending the downhole assembly adjacent the bottom of a bore hole; and means connected to the suspending means for reciprocating the fluidic power source means.

2. A system according to claim 1 in which said down-hole assembly is received within a drilling collar.

4. A system according to claim 3 in which the suspending means comprises a series of connected pipe sections forming a drill column and said fluid supply means is received within said drill column.

11. A system according to claim 8 in which the power fluid is a compressible gas and said rotating means includes a pneumatic rotor.