Bailer for top head drive rotary well drills

A bailer mounted to the derrick of a top head drive well drilling rig. The bailer includes a winch line drum mounted by a bracket to the derrick. A positive displacement hydraulic motor mounts one end of the drum and receives fluid under pressure from the existing hydraulic pressure supply. Valving is provided to allow reverse operation of the motor so equipment can either be raised or lowered relative to the derrick. The hydraulic delivery line to the motor includes a one way restrictor that will allow relatively free passage of fluid to the motor in a driving or lifting mode but will reverse flow of fluid from the motor, thereby affording a braking effect for lowering a load at a selected rate.

BACKGROUND OF THE INVENTION 
The present invention relates to bailer lines for top head drive rotary 
well drills. 
Three current types of well drilling apparatus are currently in predominant 
use for ground water drilling. They are the cable drive, the rotary table 
drill, and the top head drive rotary drills. All three forms are usually 
mounted to a truck frame and include a pivoted derrick. The derrick will 
move between a horizontal transport position and an upright operating 
position. 
The cable drive drilling rig includes a drilling tool that is suspended by 
an elongated cable. The upper end of the cable is usually connected to a 
winch and a walking beam arrangement that will alternately raise and drop 
the drilling tool. The well bore is formed by impaction of the drill tool 
against the ground surface. Operation of cable drive drilling rigs 
requires a great amount of skill in timing of the impaction strokes, 
especially as the drilling tool bores deeper into the earth. 
The cable tool drilling rigs inherently include "bailers" as well as other 
auxiliary winch-hoist arrangements that are generally driven mechanically. 
However, cable tool drilling rigs are presently outdated by the faster and 
easier-to-operate rotary drills. Additionally, cable tool rigs are 
primarily mechanically driven and modern auxiliary hydraulic equipment may 
not be added without extensive modification and further complication of 
the working mechanics. 
A more modern development in well drilling equipment is the rotary drive 
drill utilizing a "table drive". The rotary drive drills include rotary 
drill bits at downward ends of elongated rigid steel drill strings. The 
drill strings are rotated at the drilling rig and progressively lowered as 
the rotating bit operates. Sections of the drill string are added at 
regular intervals while the well is being bored and are removed in 
sections as the drill string is raised. 
The table drive rotary drill includes an upright derrick and a drive unit 
at the derrick base. The drive unit is termed the "table" and is powered 
to rotate an elongated upright "kelly". The kelly is generally of 
polygonal cross section and vertically movable within the table drive. The 
lower end of the kelly is connected to the upper end of the drill string 
and is simultaneously rotated and forced downwardly to feed the drill 
string down the hole and produce pressure on the boring head. After the 
top end of the kelly reaches the table, the entire drill string must be 
hoisted with the kelly to bring the top of the drill string to the table 
level. The drill string is then gripped so the kelly can be removed. A new 
drill string section is then attached to the string which is again 
lowered. The kelly is then connected to the top end of the new section. 
These steps are repeated until the well bore is completed. 
Well casing, a continuous pipe placed in the drilled hole to hold the 
sidewalls from caving in and to keep the well sanitary, is placed in a 
separate operation after the well hole has been completed. This involves 
removing the drill string and tool from the hole and successively lowering 
jointed casing sections down the hole to the bottom. 
A solution to the slow operation of the cable drive drill rigs and in many 
instances the table drive rigs, is the "top head drive" drill rig. The 
distinguishing characteristic of the top head drive from the table drive 
is provision of a vertically movable "top head" drive mechanism that moves 
vertically along the derrick to attach and move with the top end of the 
drill string. No kelly is required and the position of the top head over 
the bore opening allows for simultaneous insertion of drill casing as the 
hole is being bored. Therefore, a top head drive rotary drill can operate 
significantly faster than table drive or cable drive drilling rigs. 
One difficulty with top head drive drilling rigs occurs in areas where 
sandy soil is prevalent. Loose sand or mud can partially fill a drilled 
hole even though the hole has been simultaneously lined with casing. The 
hole must therefore be cleaned and a sand screen placed before a pump can 
be set. 
An effective and proven method of cleaning sand or other debris from a 
drilled hole is through use of the "sand line". An elongated, hollow 
bucket is lowered by cable down the hole. The bucket has a hinged flap on 
the bottom that will open up into the bucket but will not open downwardly. 
Impact of the bucket with the sand causes the flap to open and sand will 
fill the interior. The bucket is then lifted. The flap will close under 
the weight of the sand above and can be raised to the surface and dumped. 
The bucket is generally connected to a bailer on the derrick or frame of 
the drill rig for accomplishing this function. 
Bailers have not been standard items supplied with top head drive drilling 
rigs. The mechanism of the drive head and components for raising it up and 
down the derrick inhibit the use of a bailer line. Furthermore, it is 
reasoned that where a hole can be lined simultaneously with the drilling 
process, there is no need or use for a bailer. However, the loose sand 
situation as described above is only one in which a bailer provided on a 
top head drive derrick would be useful indeed. Known forms of bailers for 
cable drive and table drive rigs are extremely slow, underpowered, and 
both bulky and complex in nature. Table drive bailers are typically driven 
by a nonpositive displacement hydraulic motor coupled to a mechanical gear 
reduction unit. Two hydraulic lines must therefore be attached between the 
hydraulic fluid source and motor. A hydraulic brake must also be supplied 
for controlling the down hole speed when the bailer is used to lower the 
equipment down the hole. Such a brake can be effective in controlling 
lowering speed which is a considerable problem with heavy equipment. 
Without some form of speed reduction mechanism, increasing down hole 
speeds can overcome the braking effect of a nonpositive displacement 
motor. This results in free fall and damage to the down hole equipment in 
addition to the bailer components. The problem the hydraulic brake 
presents, though, is its complexity and the additional requirement of more 
hydraulic fluid lines and associated control valves to already 
over-complex hydraulic systems. 
Many current top head drive rigs make use of "jib" "hoists" to raise and 
lower casing and drill sections and, on occasion, to raise and lower 
equipment down the hole. The typical jib hoist is painfully slow and does 
not include enough cable to reach the bottom of deep wells. Other 
resources are usually sought with deep hole situations and when more than 
one round trip needs to be made up and down the hole (as with the sand 
bailing example set forth above). When bailing or similar operations are 
required, either the top head rig is moved and replaced with a cable drive 
rig (that has a bailer) or a "pump truck" with a pump setting hoist is 
positioned next to the hole adjacent the derrick. Both alternatives are 
very inconvenient. The least inconvenient of the two (using the pump 
truck) at best take the pump truck and its operator away from their 
intended duties, notwithstanding the mechanical and safety hazards of 
positioning the pump hoist boom correctly over the well without first 
moving the drill rig or lowering the derrick. The additional equipment 
crowded about the bore hole makes operations inefficient to say the least. 
In addition, the boom of a pump truck is generally substantially shorter 
than the drill derrick so special arrangements must be made when the pump 
truck is used to handle drill stem sections, casings, and other apparatus 
designed particularly for the taller drilling rig derrick. 
It therefore becomes increasingly desirable to provide a bailer attachment 
for existing top head drive drill rigs that will mount to the derrick in 
an unobtrusive position and that will function to both lift and lower 
heavy loads along a drill hole with minimal control requirements and with 
minimal interference with respect to existing hydraulic power supply 
systems. 
It is also desirable to provide a bailer attachment for top head drive 
drill rigs that includes a direct drive relationship between the bailer 
drive motor and winch drum to thereby reduce mechanical complication and 
also reduce the number of hydraulic components, lines, and controls 
utilized for such an attachment.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
A top head drive rotary drill rig is diagrammatically illustrated at 10 in 
the accompanying drawings. The rig 10 is of the type typically used for 
ground water drilling. The drilling apparatus is mounted to a conventional 
heavy duty truck 11 equipped with a rearward frame designed to carry a 
drilling derrick 12 and associated equipment. The derrick 12 is shown in 
FIG. 1 in a horizontal transport position and in FIG. 2 in an upright 
operative position. The derrick 12 is moved between the horizontal and 
upright positions by a hoist mechanism 13 composed of one or more 
hydraulic operated cylinders. 
A top head drive unit 14 (FIG. 1) is movably mounted to the derrick 12 for 
the purpose of receiving and turning a rotary drill bit and attached drill 
string. The drill string is made up of individual sections 15, some of 
which are carried within a magazine rotatably mounted to the derrick. The 
top head drive 14 and other driving units utilized by such drill rigs are 
typically powered by hydraulic fluid under pressure through a power unit 
16 that is mounted to the truck frame. Such power units typically include 
hydraulic pumps, air compressors, pump drive units, hydraulic reservoirs, 
generators, etc. and typically take up a substantial amount of the limited 
space available on the truck frame. 
The flow of hydraulic fluid and air to the various conventional components 
is typically controlled by a valving apparatus at a control panel 17. The 
panel 17 is usually located as indicated in FIGS. 1 and 2, closely 
adjacent to the lower end of the derrick at the rearward end of the truck. 
The present bailer is generally illustrated at 20 in FIGS. 1 and 2 and is 
shown more specifically in FIGS. 3 and 5. It is situated on the derrick 12 
at an inwardly facing derrick side 21. The bailer 20 is spaced downwardly 
from the derrick top 22 to clear the cab of the truck and other equipment 
on the truck frame when the derrick is in the inoperative horizontal 
position. 
The bailer provides a cable 23 (FIG. 4) that extends upwardly from the 
bailer over a sheave 24 at the derrick top 22. The cable 23 can extend 
from the sheave down the derrick and into a drilled hole. The sheave 24 is 
oriented tangentially to the vertical center line of the derrick (FIG. 3) 
to prevent rubbing of the cable along the casing walls as the bailer is 
operated to lift and lower equipment along a drilled hole. Placement of 
the sheave also permits retraction of the cable to the derrick top 22. The 
bailer can therefore be used to handle relatively long objects such as 
drill string sections and casing sections. 
The present bailer 20 is mounted to the derrick by a bracket 26 (FIGS. 3 
and 5). The bracket is substantially U-shaped and formed of heavy metal 
plate. It includes a base 27 that mounts flush to the derrick side 21. An 
outwardly extending bracket side 28 forms one leg of the "U" shape and an 
opposite side 30 forms the other leg. The side 28 includes a motor 
receiving hole 29 and the opposite side 30 includes an inwardly extending 
slot 31. The base of the slot 31 and the center of the hole are 
substantially coaxial across the bracket. 
The bracket 26 rotatably mounts a bailer line drum 35 between the sides 28 
and 30 for receiving and playing out the cable 23 (cable 23 is not shown 
in FIG. 5). The drum 35 is coaxial with the base of slot 31 and mounting 
hole 29. The rotational axis of the drum 35 is transverse to the derrick 
and parallel to the rotational axis of the sheave 24. 
The bailer line drum 35 includes a pair of spaced end plates 36 held on a 
central spool or core 37 (FIG. 5). The spool 37 spaces the end plates 36 
apart by a distance slightly less than the distance between bracket sides 
28 and 30. A spline receiving billet or socket 38 is centered on the drum 
axis at one end of the drum. A shaft 39 protrudes from an opposing end of 
the drum to extend through the slot 31. A bearing 42 is mounted on the 
bracket side 30 to receive and journal the shaft 39 on the bracket. 
Bearing 42 is preferably bolted to an outside surface of bracket side 30. 
Mounting fasteners are thus exposed for ease in removal of the bearing and 
subsequent removal of the drum from the bracket. 
The end of the drum opposite bearing 42 is rotatably mounted by the 
driveshaft spline 48 of a hydraulic motor 45. The motor 45 is of the 
positive displacement variety, preferably of the reciprocating piston 
type. It is mounted to the one side 28 of bracket 26 and extends through 
mounting hole 29 to connect directly with the winch line drum 35. The 
spline 48 is provided at the end of a single output shaft for the motor 
45. The spline is slidably received within the complementary billet 38 of 
the winch line drum as shown in FIG. 5. The spline and drum can thus be 
separated simply by moving the motor and drum axially apart. 
The motor 45 is operated by hydraulic pressure through a hydraulic system 
50 (FIG. 3). The hydraulic system 50 is adapted for connection into the 
existing power unit 16 of the drill rig. The conventional system typically 
includes a reservoir 51 (FIG. 3) that holds a supply of hydraulic fluid in 
reserve for one or more pumps 52. It is not unusual for a top head drive 
drilling rig to have several hydraulic pumps operating simultaneously for 
different purposes. Flow from the pump or pumps 52 is controlled at the 
panel 17 through a series of flow control valves 53 commonly termed 
"stacker" valves. Lines 54 from the valves 53 extend to the various 
components to selectively receive pressurized hydraulic fluid from an 
associated motor. Common delivery lines 55 and return lines 56 
interconnect the pump or pumps 52, control valves 53 and the reservoir 51. 
A valve means 58 is included for the hydraulic motor 45 that may be 
situated on the control panel 17 in relation to the remaining flow control 
valves 53. The valve means 58 may be comprised of a standard three 
position selector valve openly connected to the main delivery and return 
lines 55 and 56 on one side thereof. A straight through section 59 of the 
valve means 58 will allow normal circuitous flow of hydraulic fluid to the 
motor 45 while a cross over section 60 provides for reverse flow. 
A hydraulic fluid delivery line 62 extends between the valve means 58 and 
the motor 45. It leads from an end 63 connected to the valve 58 to an end 
64 that is operatively connected to the motor. A return line 65 also 
extends between the motor 45 and valve means 58. The return line 65 leads 
from an end 66 connected to the valve means to an end 67 connected to the 
motor 45. The lines 62 and 65 deliver and return fluid through the valve 
means 58 from and to the pump 52 and reservoir 51. Flow of fluid through 
the lines is reversed in response to movement of the valve means 58 to 
bring the cross over section into open communication with the line ends. 
A one way flow restrictor 70 is located between the delivery line end 64 
and motor 45. The restrictor 70 is shown in schematic form by FIG. 4. It 
includes a flow through branch 71 and a reverse flow restrictor branch 72. 
Flow is controlled through the restrictor by a spool or shuttle 73. 
Selective adjustment of pressure required to move the spool or shuttle 
between operative and inoperative positions is provided through an 
adjusting mechanism 74. Reverse flow of fluid through the device will, 
after a selected back pressure builds up, shift the shuttle 73 to open the 
restrictor branch 72 and allow restricted flow of fluid in a reverse 
direction. 
A manifold means 76 is provided to directly mount the restrictor 70 to the 
manifold of the motor 45. A single hydraulic connection to the delivery 
line is therefore all that is required for connection between the motor 
and valve means 58. The manifold means 76 is basically comprised of a 
block secured to the motor by elongated mounting bolts (not shown). A 
first passage 78 extends partially through the block to receive and mount 
the delivery line end 64. The opposite end of the passage 78 leads 
directly into the restrictor 70. A second passage 82 extends from the 
output side of the restrictor 70 to openly communicate with the motor 45. 
"O" ring seals 81 are provided at the various openings in the block to 
seal the manifold to the restrictor 70 and motor 45. 
The present bailer assembly may be relatively easily mounted to existing 
top head drive rotary drill rigs. Installation may be initiated by 
mounting the bracket, winch line drum, and motor to the derrick. This is 
done firstly by locating a position on the inward derrick side 21 downward 
of the top 22 so tha bracket and attached elements will clear the truck 
cab and existing equipment on the frame when the derrick is in the 
horizontal transport position. The bracket 26 is mounted to the derrick 
securely by appropriate mounting fasteners (not shown) that will 
facilitate removal of the bailer for maintenance or repair. 
With the motor mounted in fixed position on the derrick, the hydraulic 
lines can then be accurately measured and connected. The delivery line is 
connected to the restrictor through the appropriate fitting on the 
manifold means 76. This line then leads down the derrick to the valve 
means 58. The return line 65 is similarly connected between the motor 45 
and valve means 58. Short tap lines are spliced into the main delivery and 
return lines 55 and 56 leading from the reservoir and pump to the stack 
valves. This connection can be made on many existing top head drill rigs 
at any of several locations, depending upon the output capacity of the 
associated pump 52. I have found that interconnection with the delivery 
and return lines to the derrick hoist mechanism 13 is appropriate since 
the bailer need not be used when the derrick is being raised or lowered, 
nor is the derrick raised or lowered when the bailer is operating. 
Therefore, full capacity of hydraulic fluid may be diverted from the hoist 
mechanism to the motor 45. 
The sheave 24 is then mounted to the derrick top. The cable 23 is trained 
from the winch line drum over the sheave and down the derrick to an 
appropriate intermediate anchor point. The bailer assembly is then 
completely installed and ready for operation. 
To describe operation of the present invention, a particular working 
situation will be given by way of example. It is to be understood, 
however, that the present bailer may be used for a wide variety of other 
functions for both down hole purposes and above ground operations. 
When a situation is encountered where the drilled and casing-lined hole 
fills partially with loose sand or mud, the present bailer may be utilized 
to quickly and efficiently operate a sand line arrangement. Firstly, the 
drill steel is pulled by conventional methods from the drilled hole. A 
sand bucket (not shown) is then connected to the free end of the cable 23. 
The operator then switches the valve means 58 to the cross over section 60 
so that pressurized fluid is delivered through the return line 65 and 
returned through the delivery line 62. Fluid flow will begin only after 
pressure through the return line reaches a prescribed value as set by the 
adjusting mechanism 74 of the restrictor 70 (for example, 400 psi). When 
the pressure exceeds the prescribed value, the spool or shuttle 73 will 
shift and allow restricted flow through the reverse branch 72 of the 
restrictor. 
Reverse flow of fluid through lines 62 and 65 then causes operation of the 
motor 45 in reverse to play out the cable 23 from the drum 35. The rate of 
descent, of course, depends on the flow rate of fluid through the motor. 
The flow rate can be controlled by the usual control mechanism which 
typically includes regulating the pressure from the pump 52, varying the 
rpm of the pump driving unit. Similarly, the rate of descent can be slowed 
by decreasing the flow through the motor and stopped by lowering the 
pressure of delivered fluid below the prescribed value set by the 
adjusting mechanism 74. 
Preferably, the drum is operated at a relatively high rate of speed to 
lower the bracket quickly down the hole. The bucket will then drop and 
sink partially in the accumulated sand or mud at the bottom of the hole 
and become partially filled. At this time, the valve means 58 can again be 
operated to bring the section 59 into communication with lines 62 and 65. 
The motor 45 will then operate to pull the bucket back up the drilled 
shaft. In this situation, the delivery line 62 receives pressurized fluid 
and the return line 65 serves its intended purpose to return fluid from 
the motor back to the main return line 56. The restrictor valve will 
automatically move its shuttle 73 back to the normal operating position 
due to lack of back pressure holding it in the reverse flow mode. Free 
flow of fluid to the motor is therefore allowed through the delivery line, 
restrictor, and manifold means. Return of fluid through the return lines 
is unhampered. The motor is therefore caused to operate in a normal 
forward mode to rotate the winch line drum 35 to gather the cable 23 and 
pull the bucket up the drilled shaft. The bucket may then be emptied and 
subsequently returned down the hole to receive the next load. 
Combination of the present bailer and the top head drive rotary drill rig 
provides a full range of operations for the drill rig without requiring 
additional equipment such as a cable tool rig or a pump truck for 
performing operations as described above. The present bailer can be easily 
and inexpensively added to existing top head drive drill rigs by simply 
mounting the bracket to the derrick and connecting the hydraulic lines to 
the existing return and delivery lines from the pressure supply systems. 
The specific hydraulic motor 45 can be selected from a variety of positive 
displacement motors that, along with the restrictor 70, eliminate the need 
for supplying a braking arrangement to control down hole speed in the 
reverse operation mode. Furthermore, the motor 45, being a positive 
displacement type, may be selected from a variety of such motors that will 
operate at substantially higher speed and capacity than is provided for 
other standard forms of winch assemblies. For example, a capacity of 1140 
lbs. of lift at a speed of 973 feet per minute is feasible. These 
features, enabling the single drill rig to perform various operations 
without assistance, substantially decreases the drilling time in many 
situatins. 
It is to be understood that the above description and attached drawings are 
given merely byway of example to set forth a preferred form of the present 
invention. The following claims are given to more specifically define the 
scope of my invention.