Helicopter portable earth drilling apparatus

A portable earth drilling apparatus adapted for helicopter transportation has been designed in light modular form and particularly adapted for use at high elevations under circumstances where prior art drill rigs are not capable of efficient operation.

BACKGROUND OF THE INVENTION 
Helicopter portable drill rigs have been developed for use in remote 
locations where it is difficult to transport and locate more conventional 
earth drilling equipment. Examples of such helicopter portable drill rigs 
are (1) a drill rig marketed under the name Heli-Drill by Big Indian 
Drilling, Company, Ltd. of Calgary, Alberta, Canada, (2) a drill rig 
marketed under the name Midway Copter-Rig model 13MH by Midway 
Manufacturing and Supply, Inc., a subsidiary of Texas International 
Company of Odessa, Texas, and (3) a drill rig marketed under the name 
Mayhew Model 50 Portable Demountable Drill by Gardner-Denver of Dallas, 
Texas. Prior to the present invention, however, helicopter portable drill 
equipment has suffered from any one or more of several disadvantages which 
makes them unsuitable for drilling in hard rock at high elevations such as 
in the Rocky Mountains. The typical disadvantages of the prior art 
helicopter portable drill rigs are that they are so heavy that they 
require relatively large and expensive helicopter transportation making 
the drilling operation unduly expensive and they do not operate 
efficiently in the thin air prevelent at high altitudes. 
The lack of a portable drill rig capable of operating efficiently at high 
altitudes is understandable since to design such a drill rig requires the 
blending of component parts which are capable of operating in thin air and 
yet which are light enough that they can be transported by smaller, 
relatively inexpensive helicopters. 
The need for helicopter portable drill rigs which will operate at high 
altitudes has increased within the last decade due to the diminishing 
supply of petroleum products necessitating the search for these products 
in more remote areas, some of which are at high altitutes. The search for 
petroleum products frequently involves seismic exploration work prior to 
the drilling of an exploratory well with the seismic work typically being 
conducted with the use of dynamite explosions that set off sound waves 
through the earth's crust which are recorded by specially designed 
equipment to give the exploration company a better picture of the 
subsurface rock formation. For environmental reasons, it is desirable to 
set the explosive charge below the surface of the earth but this requires 
drilling shallow holes into which the dynamite charge can be placed and 
prior to the present invention economical portable drilling equipment 
suitable for drilling in hard rock at high elevations, such as in the 
Rocky Mountains, has not been available. 
SUMMARY OF THE INVENTION 
The helicopter portable drilling apparatus of the present invention was 
designed specifically for transportation by relatively small, inexpensive 
helicopters and for operation at high elevations where the air is 
relatively thin thus rendering prior art apparatuses inefficient. 
Utilizing the specifications of a particular helicopter which is small and 
relatively inexpensive in comparison to helicopters required to lift 
heavier portable rigs, the present invention was designed in modular form 
so that no module would weigh more than 1300 pounds at 10,000 feet 
elevation. The use of a larger helicopter capable of lifting heavier 
modules as used in prior art drilling equipment typically triples the 
expense for helicopter transportation and thus one can readily appreciate 
the advantages of a light drilling apparatus as in the case with the 
present invention. 
Recognizing the weight limitations imposed on the drill rig, it was 
determined in the development of the present invention that it would be 
very difficult to put a customary amount of weight on the drill bit itself 
as is possible at lower elevations with heavier drilling equipment so a 
percussion type tool was selected for doing the actual drilling. The use 
of the percussion type tool necessitated a compressor package that would 
deliver enough air at 10,000 feet to produce the necessary air to run the 
percussion type tool. To overcome the thin air limitations, screw type 
compressors were selected to deliver enough pressure to run the percussion 
type drilling tool and these compressors are powered by a special 
industrial engine which was selected after experimentation with other 
power systems that did not prove efficient at elevations of about 10,000 
feet. Further, it was difficult to generate enough air pressure to 
efficiently operate the percussion type drill tool as well as the other 
driving motors necessary to advance the drill bit into the earth. 
Accordingly, the preferred embodiment of the drill rig includes a separate 
hydraulic system for driving the motors which advance the drill bit into 
the earth saving all of the compressed air for use in the percussion type 
drill tool which in the preferred embodiment is carried on the lower end 
of the drill stem. 
After much experimentation, the final preferred form of the drill rig of 
the present invention encompassed three modular components. The first 
component is a hollow tubular frame carrying a drill rig with the tubular 
frame serving as an air reservoir for the compressed air and the drill rig 
including means for rotating a drill stem while advancing the drill stem 
into the earth. The drill stem has a percussion type tool and a drill bit 
on its lower end for breaking the rock as the tool is advanced into the 
earth. The second module is a compressor package utilizing a pair of screw 
type compressors, a cooling system for the compressors and separator 
equipment adapted to separate the lubricant for the compressors from the 
air. The third module is the power package, which, as mentioned 
previously, includes a carefully selected industrial engine adapted to 
perform efficiently at high elevations. Either the power module or the 
compressor module includes a hydraulic pump and reservoir for operating 
the hydraulic components of the drill rig. Each module weighs less than 
1300 lbs. At 10,000 feet elevation so that it is capable of transportation 
by a relatively inexpensive helicopter. 
The apparatus of the present invention is capable of drilling holes up to 
fifty feet in depth in hard rock at relatively high elevations and can be 
transported by a relatively small helicopter type aircraft giving the 
apparatus a capability not previously available from prior art systems. 
Other objects, advantages and capabilities of the present invention will 
become more apparent as the description proceeds when taken in conjunction 
with the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The helicopter portable drilling apparatus 10 of the present invention is 
seen in an assembled condition in FIG. 4 and as will be explained in more 
detail later, the apparatus consists of three separable modules, (1) a 
frame-drill rig module 12, (2) a compressor module 14 and (3) a power 
module 16. 
Each module has been designed to not only perform efficiently in enabling 
the drilling apparatus to drill holes up to fifty feet in depth at high 
altitutes in very hard rock, but has also been designed to weigh no more 
than 1300 lbs. so that they can be transported by an economically operable 
helicopter. Figs. 1 through 3 show the three separate modules being 
transported by a helicopter 17 and as will be explained later, the modules 
slide easily into the assembled condition of FIG. 4 so that once the 
frame-drill rig module 12 has been positioned on the ground, both the 
compressor and power modules 14 and 16 respectively can simply be lowered 
into place on the frame-drill rig module by the helicopter. The modules 
are then interconnected in a manner to be described later for operation of 
the apparatus. 
The frame-drill rig module 12 is illustrated in FIGS. 2, 4 and 5 to include 
a base frame portion 18 and a drill rig 20 with the frame 18 supporting 
the drill rig in a vertical orientation at one end of the frame. The frame 
is of generally trapezoidal configuration on its bottom, as can be 
appreciated in FIG. 5, having a pair of longitudinal side frame members 
22, a pair of end frame members 24 and two cross frame members 26 
interconnecting the side frame members at positions between the two end 
frame members. Reinforcing struts 28 interconnect the side frame members 
with the end and cross frame members to reinforce the frame system. At the 
narrowest end of the frame 18, which will be referred to as the forward 
end, the frame includes a pair of riser frame members 30 which are 
inclined forwardly and inwardly in an upward direction to cooperate in 
forming the support-interconnect for the drill rig. The risers 30 are 
braced by a cross member 32 at a location approximately midway of their 
length and are braced in their upstanding position by strut members 34 
interconnecting the risers with the side frame members 22. 
The base frame 18 is also provided along its perimeter with triangular 
shaped guides 36 which serve to guide the compressor and power modules 14 
and 16 respectively into position on the frame-drill rig module 12 when 
the compressor and power modules are lowered as by the helicopter 17 onto 
the frame. Once in position, the compressor and power modules are properly 
oriented for interconnection and do not need to be mechanically connected 
to the frame-drill rig module to hold their positions during operation. 
The drill rig 20 includes a screw feed mast 28 and drill stem tubing 40 
connected to the mast with three separate power systems adapted to 
cooperate in advancing the drill stem into the earth as a hole is being 
drilled. The mast 38 in the preferred form is a commercially available 
item manufactured and sold by Gardner-Denver of Dallas, Texas under the 
designation 2 MSUC Aluminum Shell Screw Feed Mounting. This mast basically 
consists of a channel member 42 extending vertically and being connected 
to the frame 18 of the apparatus by suitable connection means 44 which are 
mounted at the upper end of the risers 30. A threaded screw rod 46 is 
rotatably mounted within the channel member 42 and is operably connected 
to a drive motor 48 mounted on the upper end of the channel member. The 
drive motor 48 serves to selectively and reversibly rotate the screw rod 
46 to move the drill stem vertically as will be explained later. 
The lower end of the mast 38 has a bracket member 50 with a vertical 
opening (not seen) therethrough adapted to slidably receive the drill stem 
tubing 40. The drill stem tubing extends through the bracket 50 so that 
the drill stem can be guided into the hole during the drilling operations. 
The upper end of the drill stem tubing is operably connected to a 
hydraulic rotary motor 52 which is adapted to rotate the drill stem tubing 
during drilling operations. The rotary motor itself is operably connected 
to the screw rod in the drill mast so that as the drive motor at the top 
of the drill mast is driven to rotate the screw rod, the rotary motor can 
be advanced up or down the drill mast as desired. Of course, during 
advancement of the rotary motor up and down the drill mast, it in turn can 
rotate the drill stem to optimize drilling operations in a conventional 
manner. 
The lower end of the drill stem 40 carries a conventional percussion type 
drill bit 54 which is the most effective type of drill bit when heavy 
weights cannot be put on the bit. 
An air hammer 56, such as of the type manufactured by TRW-Mission of 
Houston, Texas under the designation A-3015 Down Hole Air Hammer, is 
incorporated at the lower end of the drill stem 40 immediately above the 
percussion type drill bit 54. The air hammer is adapted to deliver 
repeated reciprocating blows to the drill bit so that the bit can chip 
away at rock in the process of drilling a hole in the earth. 
The rotary motor 52 rotates the air hammer 56 and drill bit 54 to 
facilitate the drilling operation. Of course, as the hole progresses in 
depth, the drive motor 48 at the top of the mast 38 is selectively 
operated to apply pressure to the drill bit by urging and advancing the 
rotary motor downwardly which in turn forces the drill stem, air hammer 
and bit downwardly. The travel length of the mast 38 is only approximately 
five to six feet so in order to get holes up to fifty feet in depth, 
lengths or sections of drill tubing are added in a conventional manner as 
the hole progresses in depth. In other words, an initial hole of five or 
six feet will be drilled by operating the air hammer, rotary motor and 
drive motor. After the five or six foot depth has been reached, the drive 
motor 48 will be reversed to lift the rotary motor 52 so that a second 
length of tubing can be added to the first length of tubing whereupon a 
second drilling operation is commenced which in effect deepens the hole 
another five or six feet before subsequent lengths of tubing are added in 
a similar manner. 
Referring now to FIGS. 2, 4 and 5, the compressor module 14 can be seen to 
include a generally box-like framework 58 supporting a pair of compressors 
60 mounted in side by side relationship at opposite sides of the module. 
At altitudes of approximately 10,000 ft. it is very difficult to obtain 
enough volume and pressure from a compressor to operate a drilling rig as 
in the present invention. Accordingly, a special screw-type compressor 
which will operate at high altitudes with more efficiency than typical 
compressors is utilized in the apparatus. An example of such a screw type 
compressor is a model BESG-A Electra-Screw R compressor manufactured by 
Gardner-Denver Company of Dallas, Texas. Two of these compressors are 
utilized in the apparatus of the present invention but one compressor 
could be utilized if it were large enough to give the volume and pressure 
necessary to operate the drilling rig and meet the weight limitations of 
the modules of the apparatus. The compressors 60 are mounted so that the 
rearward ends thereof have an input pulley 62 which is connected by a 
V-belt 64 to a drive pulley 66 which is in turn connected to the engine 68 
for the apparatus as will be described later. The drive pulleys 66 are 
rotatably mounted in the compressor module in any suitable manner so that 
they can be easily connected to the engine 68 and transfer rotary motion 
to the screw type compressors. At the center of the compressor module, 
cooling radiators 72 are disposed in front of a fan 74 which is connected 
on the main drive shaft 70 with the drive pulleys 66 so that cooling 
fluids can be circulated through the radiators 72 and the compressors 60 
to keep the temperatures of the compressors at an operating level. The 
cooling radiators are conventional and therefore will not be described in 
detail. Suffice it to say that cooling fluids are circulated through the 
radiators and the compressors with air being blown through the radiators 
by the fan to keep the cooling fluids at a desired temperature. 
A pair of separator tanks 76, connected to the output from the compressors 
60, are positioned in the compressor module 14 immediately in front of the 
compressors with the separators 76 also being a commercially available 
item adapted to separate air from the lubricant fluids utilized in the 
screw type compressors. 
Flexible conduits 78 extend from the separators 76 to the hollow tubular 
main frame 18 of the frame-drilling module so that the compressed air can 
be stored in the main frame. It can, therefore, be said that the main 
frame 18 serves as an air reservoir for the compressed air utilized in the 
operation of the apparatus. Flexible conduits 80 also extend from the main 
frame 18 to the top of the drill stem 40, which is in fluid communication 
with the air hammer 56 and suitable valves (not shown) are provided so 
that air can be selectively delivered to the air hammer from the air 
reservoir. 
The power module 16 of the apparatus 10 was also carefully designed so that 
it satisfied the weight limitations imposed by the helicopter parameters 
and so that it would deliver sufficient power at 10,000 ft. to adequately 
drive the air compressors 60 and a hydraulic pump which will be described 
later. The engine 68, is a Chrysler 318 industrial engine and was selected 
after considerable experimentation. The output shaft 82 of the engine is 
connected to the drive shaft 70 for the drive pulleys 66 in the compressor 
module 14 by a conventional universal coupling 84. Gasoline tanks (not 
shown) necessary to operate the engine are located outside the power 
module and transported separately due to weight. 
The power module includes a frame structure 86 and a hydraulic system 
including a pump 88 and hydraulic fluid reservoir 90. The hydraulic pump 
88 is disposed immediately adjacent the output of the engine 68 so that it 
is driven by the engine drive shaft 82 and the hydraulic fluid reservoir 
90 is positioned on top of the power module framework 86 in a convenient 
location. The hydraulic fluid is utilized to drive both the drive motor 
and rotary motor 52 on the drill rig and suitable fluid conduits and 
valves (not shown) connect the hydraulic pump to the drive and rotary 
motors. As mentioned previously, the hydraulic pump and reservoir could be 
mounted on the compressor module if weight limitations parmitted. Since 
the hydraulic system is conventional a detailed description thereof is not 
deemed necessary. Suffice it to say that the drive motor and rotary motor 
are operable separately from each other in both forward and reverse 
directions to enable the efficient and effective operation of the drill 
apparatus. 
Utilizing the equipment described above, it is possible to obtain air 
pressures of approximately 150 PSI with a volume of 200-300 CFM at 
altitudes of approximately 10,000 ft and also to generate sufficient 
hydraulic pressure to supplement the air pressure in efficiently drilling 
holes in relatively hard rock at high elevations to depths of up to fifty 
feet. The capabilities derived from the apparatus of the present invention 
are having a marked effect on seismic operations at high elevations which 
previously had to be carried out with surface explosions which do not give 
as accurate a reading as the subsurface seismic work possible with the 
apparatus of the present invention. Further, numerous environmental 
problems encountered with surface explosions utilized previously in 
seismic work at high elevations can be avoided due to the capabilities of 
the apparatus of the present invention. 
Although the present invention has been described with a certain degree of 
particularity, it is understood that the present disclosure has been made 
by way of example and that changes in details of structure may be made 
without departing from the spirit thereof.