Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
TTR22 ~25~081
UNDERGROUND, FLUID DRIVEN DIRECTIONAL DRILLING DEVICE
This invention relates to underground fluid driven
directional drilling devices particularly adapted for
drilling wells and mining oil, but not limited thereto.
GENERAL DESCRIPTION OF THIS INVENTION
.
There is a need in the well-drilling and oil mining
industry for a flexible, non-rotating drill string which
is capable of drilling curvilinear bore holes and
following the curved configuration as it proceeds. The
kind of drill string contemplated herein is one made up
of concatenated sections of hollow drill pipe capable of
holding a working fluid at high pressure, and of course
the articulated joints between sections of the pipe must
be capable of withstanding and containing the fluid
pressure. A further aspect of this invention is the
provision of a~ drilling head which is itself
articulating, the angulation of which can be controlled
either by adjusting the internal fluid pressure in the
drill string, or by controlling separate fluid pressures
in separate conduits associated with the drill string.
Yet another aspect of this invention is the provision of
a centering means adjacent the articulating head, having
the capability of holding the drill string at a centered
location in a bore hole.
More particularly, this invention provides an
articulated drilling head for use with a non-rotating
drill string having a central passage for carrying
working fluid under pressure to the drilling head, and
having an axis. The drilling head comprises first means
defining a first chamber adjacent the end of the drill
string, and a first stage impeller in that chamber, the
impeller being freely rotatable about the axis of the
drill string. Second means is articulably connected to
said first means for swinging movement in at least one
plane containing the drill string axis, and the second
means defines a second chamber. A second stage impeller
is located in the second chamber, connected through a
universal joint to the first stage impeller. A
~ZS~
connector means is connected to rotate with the second
stage impeller, so that a drilling bit can be attached
to turn with the second stage impeller.
This invention further provides, in combination, a
non-rotary drill string including a pipe member having a
central passage for carrying fluid under pressure, and
at least three circumferentially distributed first arms,
each mounted at one end to the pipe member for swinginy
movement in a different plane containing the axis of the
pipe member. For each first arm there is a second arm
pivotally connected at one end to the other end of its
respective first arm, such that each second arm moves in
the same plane as its respective first arm. A slidable
sleeve is mounted on the pipe member, and the other ends
of the second arms are pivotally connected to the
sleeve. The sleeve has a surface in part defining a
chamber to which fluid under pressure is admitted from
the pipe member. The fluid seeks to move the sleeve in
the direction of the first arms, so that each
articulated combination of first and second arms tends
to geniculate and urge their common pivot location
radially outwardly with respect to the pipe member, thus
centering the pipe member when it is located in a bore
hole.
This invention further provides a resilient
flexible joint between two longitudinally adjacent pipe
sections of a non-rotating drill string. The pipe
sections are hollow. One section has first means
defining a curvilinear cavity at the joint, the cavity
being a surface of revolution about an axis transverse
to the drill string. The other section has second means
defining an insert complementary with the cavity and
received snugly but slidably therein. Annular
compression spring means is located around the drill
string adjacent the location of the flexible joint. The
two pipe sections are secured to respective annular
support portions on either side longitudinally of the
spring means, so that angulation of one pipe section
with respect to the other causes the support portions to
~2S~
compress the spring means at one circumferential region
and to relax the spring means at a diametrally opposed
region thereof, so that the spring means will resist
such angulation and tend to restore the pipe sections to
alignment.
GENERAL DESCRIPTION OF THE DRA INGS
Embodiments of the various aspects of this
invention are illustrated in the accompanying drawings,
in which like numerals denote like parts throughout the
several views, and in which:
Figure l is a longitudinal sectional view, somewhat
schematically drawn, showing one context of use for the
drill string of this invention;
Figure 2 is an axial sectional view of a drill
string incorporating facets of this invention in the
upper half, and an elevational view thereof in the lower
half;
Figure 3 is a cross-sectional view taken at the
line 3-3 in Figure 2;
Figure 4 is a cross-sectional view taken at the
line ~-4 in Figure 2;
Figure 5 is a cross-sectional view taken at the
line 4-4 in Figure 2;
Figure 6 is an axial sectional view of a variation
of the articulating drill string head;
Figures 7 and 8 show two embodiments of the
mechanism utilized to angulate the drill string head;
and
Figure 9 is an alternative embodiment of one
portion of the drill string head.
DETAILED DESCRIPTION OF_THE DRAWINGS
Attention is first directed to Figure l, which
shows a mine shaft lO extending down from the ground
surface 12 to a drilling chamber 13. A drill string 14
extends downwardly along the mine shaft lO, and
undergoes a curvilinear change of direction at 16, so
that the lower portion of the drill string extends
horizontally. A guide means 18 is provided to cause the
drill string to undergo curvature. Above the ground
~s~
level 12, a support ~rame 20 is constructed, supporting
a motor and associated gearing 22 which is adapted to
cause a coupling 24 to reciprocate vertically, in order
to cause downward incremental movement of the drill
string 14. The coupling 24 is connected to a hollow
pipe 26 ~orming part of a hydraulic cylinder
arrangement, incorporating an upper cylinder 28 adapted
to feed drilling fluid under pressure downwardly through
the coupling 24 and into the hollow drill string 14.
Pressurized drilling fluid is supplied to the cylinder
28 along a line 30 from a pump 32 which draws the fluid
from a tank 34. Upstream of the tank 34 is a filtration
system 36.
When drilling in order to recover oil from tar
sands and the like, the working 41uid is usually water
at high temperature, or steam, and as the working fluid
passes through the boring head 38 at the downstream end
of the drill string 14 (seen at lower right in Figure
l), it causes rotation of the drilling bit. The exiting
drilling fluid then passes by return flow along the bore
that has been drilled, outside of the drill string, and
descends along conduit 40 into a sump 42 from which it
ls pumped or drawn by a pump 44. If the liquid in the
sump 42 contains hydrocarbons, it is pumped through line
46 to an oil recovery plant 48, from which purified
water is fed through line 50 and back to the filter 36.
Otherwise, in the case where the return fluid has no
significant hydrocarbon content, it is fed directly
through the pipe 52 and back to the filter 36, from
where it passes into the tank 34.
~ nother component within the drilling chamber 13 is
a hydraulic ram 54 having a cylinder 56 fixed in place,
and a horizontally slidable piston 58. The forward or
rightward end of the piston 58 is secured to a coupling
member 60, which is adapted to clamp the drill string 14
at a leftward location, and then urge the drill string
rightwardly as drilling proceeds. By using this
arrangement, the entire drilling force does not have to
be exerted downwardly from above the ground level 12.
~L~52081
As can be seen, the drill string 14 incorporates a
plurality of concatenated pipe sections 62, which of
course must be connected together in a fluid-tight
manner capable of containing the pressure of the fluid,
5 while still allowing the drill string to bend through a
given curvature. This requires flexible but sealed
joints between adjacent pipe sections.
As stated earlier, this invention is directed to
the provision of a drill str:ing which is a non-rotating
string. The rotation of the bit takes place at the
lower end of the drill string, where the fluid pressure
is converted to the work of rotary drilling.
Attention is now directed to Figure 2, which shows
at the leftward end a drilling head 100. The head 100
incorporates a pipe 102 which is threadably engaged at
the right with a sleeve 104, and which is threadably
engaged at the left with a further sleeve 106. The pipe
102 and the sleeve 106 together define a continuous
internal cylindrical surface 108 against which is snugly
received a cylindrical low-friction liner 110. Mounted
for free rotation within the liner 110 is a first stage
impeller 112 which incorporates a hub 114 and a
plurality of helical blades 116. The first stage
impeller 112 is not constrained axially, and is capable
of limited axial movement within the liner 108, the
limitation being a result of the connection between the
first stage impeller 112 and a second stage impeller 118
which includes a hub 120 and a plurality of helical
blades 122. The second stage impeller 118 is fixed to a
housing 124, which has a cylindrical outer surface
surrounded by a thin, low-friction collar 126. The
collar 126 is separated centrally to allow for the
projection of an annular flange 128 which is integral
with the housing 124. The flange 128 projects outwardly
into a chamber 130 defined within a forward sleeve 132,
the sleeve 132 having an inner wall 134 and an outer
wall 136, the two walls 134 and 136 being joined by an
annular wall 138. At the rightward or upstream end of
the sleeve 132, there is a threaded connection with a
~2~ii2t~
member 140, which defines at 142 a spherical cavity
which is of limited circumferential extent. An
identical such cavity is found at the diametrally
opposed location (not visible in Figure 2). The center
of curvature of the cavity 142 is shown at 144. The
member 140 is threadably connected to a further member
1~6, which defines another spherical cavity 148 of
limited circumferential extent, and also defines a
diametrally opposed identical such chamber. It will be
seen that the cavity 148 has the same ce~ter of
curvature 144 as the cavity 142, but has a greater
radius.
The member 146 defines a shroud 150 which
completely surrounds the sleeve 106, but is spaced
therefrom. As can be seen, there is a gap 152 between
the rightward inner terminal portion of the shroud 150
and the sleeve 106. The purpose for the gap 152 will
become apparent in the description that follows.
The first stage impeller 112 is connected to the
second stage impeller 118 by a universal coupling 154 of
standard construction. This connection ties the two
impellers together in an axial sense, but allows the one
to articulate with respect to the other. The universal
coupling 154 also requires the two impellers to rotate
together.
Returning to the chamber 130, it will be seen that
there is provided a further chamber 156, defined by the
member 140, the chamber 156 being similar to the chamber
130, in that the member 140 has an inner wall 158 and an
outer wall 160 defining the inner and outer limits of
the chamber 156.
Within the leftward chamber 130 there is a spring
means 162, preferably a plurality of conical washers,
sometimes known as Belleville washers, which are in
compression and urge rightwardly against a plurality of
ball bearings 164, which in turn press rightwardly or in
the upstream dixection against the flange 128.
Similarly in the rightward chamber 156 there is an
e~uivalent spring means 166, which urges leftwardly
'~2~
against ball bearings 168, which in turn press
leftwardly or in the downstream direction against the
other side of the flange 128. The arrangement just
described thus provides a resilient retention mechanism
for urging the flange 128 toward a position in which the
forces on the left and on the right are in balance.
However, axial force rightwardly against the drilling
head, shown at 170, can dispLace the second stage
impeller 118 and the flange :L28 rightwardly, until the
axial force on the head 170 :Ls releasedO In essence,
the arrangement provides a shock-absorption for axial
forces undergone by the head 170. It will be
appreciated that, if the head 170 moves rightwardly with
respect to the sleeve 132, then both of the impellers
will move rightwardly the same distance.
Attention is now directed again to the sleeve 106,
which is threadably engaged with the pipe 102. The
sleeve 106 integrally defines, at its downstream or
leftward end, a first spherical insert 172 which is
received in the cavity 142, and a second spherical
insert 174, which is received in the other spherical
cavity 148. The sleeve 106 defines two identical such
inserts at the diametrally opposed position, not visible
in Figure 2.
It will thus be appreciated that limited
articulating capability exists between the sleeve 106
and the combination of the member 140 and the member 146
which are threadably engaged with each other. It will
now be understood why the gap 152 must be provided,
namely to permit this articulation to take place. When
articulation occurs, the direction of drilling is
angulated slightly with respect to the remainder of the
adjacent string, and a change in direction can be
` initiated.
The device which accomplishes the change in
direction in a positive manner is shown at 176, and will
be described in greater detail with reference to another
figure.
~252~8~L
Attention is now directed to the pipe 102, which
provides at its leftward or downstream end a mounting
ring 180 to which three downstream arms 182 are
pivotally connected for swinging movement in three
different planes, each plane containing the axis of the
pipe 102. In other words, each of the downstream arms
182 is capable of swinging outwardly away from the axis
of the pipe 102, or alternatively toward the axis. In
the embodiment shown, the three downstream arms are
distributed at 120 intervals around the circumference
of the pipe 10~. For each downstream arm 182 there is
an upstream arm 184 which is pivotally connected at one
end to the upstream end of the respective downstream arm
182, in such a way that each of the upstream arms moves
in the same plane as its respective first arm. Thus,
the movement of each upstream arm 184 is constrained to
be within a plane which contains the axis of the pipe
102. The numeral 186 defines the pi~ot axis between
each pair of upstream and downstream arms. A slidable
sleeve 188 is mounted on the pipe 102, and also on the
sleeve 104. It will be seen that the outer diameter of
the sleeve 104 at the location in question is slightly
greater than the outer diameter of the pipe 102, and the
reason for this will become apparent presently. Thus,
the sleeve 188 has an equivalent outward step, to
accommodate the difference in diameters. The sleeve 188
has at the rightward end a mounting means 190 such that
it can be pivotally connected to the rightward or
upstxeam end of each of'the upstream arms. The pivot
axis in question is shown at 192.
It will be appreciated that the sleeve 188 is shown
in its furthest rightward or furthest upstream position
in Figure 2, this being determined by the step mentioned
earlier. It can also be visualized that, as the sleeve
188 mo~es leftwardly, each pair of upstream and
downstream arms geniculate to urge their common pivot
location 186 radially outwardly with respect to the pipe
102, thus centering the pipe 102 when it is located in
any drilled shaft or bore hole.
:~2S~08~L
The leftward or downstream movement of the sleeve
188 is caused by the admission of pressurized fluid from
inside the pipe 102, through a radial bore 196, and into
a chamber defined in part by a wall of the sleeve 188
extending between the smaller diameter portion and the
larger diameter portion. It will thus be understood
that the pressure of the working fluid within the pipe
102 seeks continuously to move the sleeve member 188 to
the left, thus continuously urging the common pivot
locations 186 of the pairs of arms outwardly, thus
continuously seeking to center the pipe 102.
The ring 180 is located adjacent the rightward or
upstream end of the shroud 150, as can be seen in Figure
2. Between these two is located an annular, flexible
sealing element 200, for the purpose of keeping working
fluid which is passing outwardly alongside the pipe 102
from entering the space within the shroud 150 and
possibly interfering with the operation of the control
of the angulation for the head.
Turning attention now to sleeve 104, it will be
seen that the same is threadably connected to a collar
202, and that the sleeve 10~ and collar 202 respectively
define a first spherical cavity 204 of limited
circumferential extent, and a second spherical caviiy
206 also of limited circumferential extent. These two
members define identical such cavities at the
diametrally opposed location, but these are not seen in
Figure 2. Receivable in the cavities 204 and 206 are
spherical inserts 208 and 210, both being integral with
a sleeve 212 which is threadably engaged with a pipe
section 214 of the drill string. The pipe section 214
is of substantial length compared with the other
portions described previously, and constitutes a primary
or main section of the drill string. Its length will be
determined by the desired radius of curvature for the
drill string as it angulates between a vertical
orientation and a horizontal orientation.
Between the insert 210 and the sleeve 104 there is
defined a chamber in which a sealing member 216 is
~252(~
provided. A similar sealing member is provided in the
corresponding chamber at the diametrally opposed
location.
The pipe section 214 carries at its downstream end
S a ring 218, which is spaced axially from the rightward
end of the collar 202. In the gap between these two
there is provided a plurality of conical washers 220,
which are constantly in compression and thus seek to
push the ring 218 and the collar 202 away from each
other in the axial direction. It will thus be
appreciated that, as the sleeve 104 angulates with
respect to the pipe section 214, the conical springs 220
will be compressed at one circumferential location, and
relaxed at the opposed location. This means that such
articulation will be resisted by the springs, which will
seek constantly to maintain the pipe section 214 and the
sleeve 104 in approximate axial alignment. A protective
plastic cap 222 is provided to keep extraneous material
away from the conical springs 220. At the rightward end
in Figure 2, an identical such articulated joint is
shown between the pipe section 214 and a further pipe
section 224. The two joints are identical in terms of
the main functioning of the elements, although the
dimensions are slightly different. The joint shown at
the right in Figure 2 is between two similar pipe
sections, whereas the joint shown at the left is between
the furthest downstream pipe section and the upstream
portions of the head 100.
The limited circumferential extent of the spherical
connection at the right in Figure 2 is visible in Figure
5. In Figure 5, a spherical insert 226 is provided at
one location on a sleeve 228, and an identical such
insert 230 is provided at the diametrally opposed
location. The rightward or upstream end of the pipe 214
provides spherical cavities complementary to the inserts
226 and 230. A first protective collar 232 is threaded
on the pipe 214 and defines a spherical cavity for a
second insert 234 provided on the sleeve 228. Both the
sleeve 228 and the next upstream pipe section 224 are
~S;~C~8~
11
threaded to a collar 236, as can be seen at the right in
Figure 2. ~etween the collars 232 and 236 are located a
plurality of conical springs 240 similar in function to
the springs 220. A cap 242 keeps the springs 240 free
of contamination.
Attention is now directed to Figure 6, which shows
a slightly different embodiment for the drilling head.
In Figure 6, the first stage impeller 250 is connected
by a universal joint 252 to a second stage impeller 254.
The second stage impeller 254 is secured to a rotary
sleeve 256 having an external thread 258 at its
downstream end, for receiving the drilling bit (not
seen).
In the embodiment shown in Figure 6, the spherical
joint between the sleeve 260 and the member 262 is
equipped with ring seal 264, and with sliding seals 266.
Otherwise, the basic stru~ture is similar to that
described in connection with Figure 2.
Attention is now directed to Figures 2, 6, 7 and 8,
for a description of the device which accomplishes the
positive angulation of the downstream portion of the
drilling head with respect to the upstream portion
thereof.
In Figure 7, the sleeve 106 is drawn in section,
and it can be seen that a first cylinder 262 is mounted
in the wall of the sleeve and projects outwardly
therefrom. The mounting can be done by way of a
threaded connection. The cylinder 262 defines an inward
shoulder 264 at the inward end, and a further shoulder
266 at the outward end. Slidably mounted within the
cylinder 262 is a further cylinder 270 having a first
outwardly projecting annular portion 272 which slides
snugly against the inner surface of the cylinder 262.
The cylinder 270 has an outer surface 274 which slides
snugly against the inner surface 276 at the top of the
cylinder 262. There is thus defined an annular chamber
280, to which pressurized fluid can be admitted through
a port 282 in the side of the first cylinder 262.
~25;~
The cylinder 270 is configurèd at the top similarly
to the cylinder 276, and thus defines an inwardly
projecting annular portion 284 which Eurther defines an
upper shoulder 286. The inner cylinder 270 also defines
a lower shoulder 288.
A piston 290 is slidably mounted within the inner
cylinder 270, the piston having a cylindrical upper
portion which smoothly slides within the upper part of
the cylinder 270, and ~urthe:r has an outward annular
flange 292 which slides against the larger-diameter
inner bore of the inner cylinder 270. There is thus
defined a further annular chamber 296 to which fluid can
be admitted through a port 298.
Mounted adjacent the cylinder 262 is a
pressure-sensitive valve 302, the valve 302 defining an
internal chamber 304 which is connected along a bore 306
to the fluid pressure inside the sleeve 106. As can be
seen, the bore 306 communicates with a frusto-conical
passageway 308 at the bottom of the valve 302 which
opens into the chamber 304. Stopping the frusto-conical
passageway 308 is a frusto-conical stopper 310 which is
connected to a pin 312 having a conical point 314
adapted to be inserted into a similarly shaped opening
316 at the top of the valve 302, to stop the same~ A
compression coil spring 31B urges the combination of the
pin 312 and the stopper 310 downwardly to block the
frusto-conical passageway 308, and to open the opening
316. Fluid conduits are connected between a port 320 in
the side of the valve 302 and both the port 282 and the
3~ port 298 in the cylinder 262 and the cylinder 270-
respectively.
In order to activate the piston 290, the fluid
pressure inside the sleeve 106 (i.e. inside the entire
drill string) is increased, to the point where it will
lift the stopper 310 upwardly out of the frusto-conical
passageway 308, thus admitting pressurized fluid to the
chamber 304, thus in turn admitting pressurized fluid to
the annular chambers 280 and 296.
S~O~l
13
It must be understood that, normally, when the
valve 302 is closed, both the cylinder 270 and the
piston 290 are pushed to the outermost position by fluid
pressure within the sleeve 106, which directly contacts
the underside of both of these elements. However, when
the fluid pressure passes through the valve 302 and into
the chambers 280 and 296, the outward pressure on the
piston 290 is relaxed or counterbalanced, which means
that the piston does not push outwardly with the same
degree of force.
By making the valve arrangement for only one of the
pistons and not the other, it will be understood that
the non-valved piston will always push radially
outwardly with maximum force depending upon the pressure
of the fluid within the sleeve 106, but that the force
with which the valved piston presses outwardly is
controllable, precisely by controlling the fluid
pressure within the sleeve 106. When the valve 302
trips, thus allowing fluid pressure to be admitted to
the chambers 280 and 296, the continual outward pressure
of the unvalved piston at the diametrally opposed
location will cause the drilling head to articulate in
such.a way that the shroud 150 moves toward the valved
piston and away from the non-valved piston. This causes
a bending of the direction of drilling, which is what is
desired.
In Figure 8, the two cylinders 262 and 270 are
shown together with the piston 290, as in Figure 7.
However, there is no valve equivalent to the valve 302.
Instead, a separate conduit carrying a separately
controlled fluid such as hydraulic oil is directly
connected through the port 282 thus being admitted into
the annular chamber 296. From the chamber 296 it can
pass freely through the port 350 into the annular
chamber 280.
The arrangement of Figure 8 is suitable when three
or more pistons are provided at equal intervals around
the sleeve 106, to provide an embodiment in which the
angular articulation of the drilling head is not limited
:~2S~
14
to a single plane. It will be appreciated that the
spherical cavities and inserts provided at the
articulation point for the head could be replaced with a
true spherical joint, al]owing articulation in any given
direction. In such an embodiment, it would be
preferable to provide three, or possibly more, pistons
of the kind shown in Figure 8, and to run separate
hydraulic conduits to each associated outer cylinder
262, so that the pistons can be separately controlled.
Attention is now directed to Figure 9, which
corresponds to the portion at upper left in Figure 2.
The difference in Figure 9 i9 simply that the housing
124a is a composite of two members 400 and 402 threaded
together, each of the members 400 and 402 providing an
outwardly extending annular flange 404, 406,
respectively, and each flange 404, 406 being located
within a separate chamber defined by exterior members.
However, each chamber is similar in construction and
function to the single chamber illustrated in Figure 2.
Within each chamber there are provided resilient conical
washers in compression, along with ball bearings
immediately adjacent each flange on either side. The
construction will be self-evident from the figure, and
does not need to be described in detail.
It will further be appreciated that the conical
compression washers of the Belleville type could be
replaced with other equivalent resilient members, for
example resilient rings of various cross-sectional
shapes.
While several embodiments of this invention have
been illustrated in the accompanying drawings, it will
be evident to those skilled in the art that changes and
modifications may be made therein, without departing
from the essence of this invention, as set forth in the
appended claims.
