U.S. patent number 3,667,556 [Application Number 05/000,979] was granted by the patent office on 1972-06-06 for directional drilling apparatus.
Invention is credited to John Keller Henderson.
United States Patent |
3,667,556 |
Henderson |
June 6, 1972 |
DIRECTIONAL DRILLING APPARATUS
Abstract
This invention relates to a directional drilling apparatus. More
particularly, the invention is a drilling tool including provisions
for changing the direction of drilling of a borehole, the tool
including a tubular body having means at the upper end for
attachment of a drill string, a drill bit affixed to the lower end
of the body by means of a slip clutch drill bit so that the drill
bit is rotated when the tubular body is rotated while permitting
the drill bit to be rotated independently of the body, means within
the tubular body for rotating the drill bit, and means controllable
from the surface of the earth of varying the angle of the drilling
axis of the drill bit relative to the tubular body.
Inventors: |
Henderson; John Keller (Tulsa,
OK) |
Family
ID: |
21693807 |
Appl.
No.: |
05/000,979 |
Filed: |
January 5, 1970 |
Current U.S.
Class: |
175/73;
175/107 |
Current CPC
Class: |
E21B
7/068 (20130101); E21B 4/02 (20130101) |
Current International
Class: |
E21B
4/02 (20060101); E21B 7/04 (20060101); E21B
7/06 (20060101); E21B 4/00 (20060101); E21b
007/04 () |
Field of
Search: |
;175/73,74,107,61 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Champion; Marvin A.
Assistant Examiner: Favreau; Richard E.
Claims
I claim
1. A drilling tool including provision for changing the direction
of drilling of a borehole comprising:
a tubular body positionable in a well borehole having means at the
upper end thereof for attachment to a rotatable drill string
extending downwardly from the earth's surface for the rotation of
said tubular body;
a drilling bit affixed to the lower end of said tubular body, the
rotation of said drilling bit about its drilling axis serving to
extend the borehole in the direction of the drilling axis;
a slip clutch means rotatably coupling said drilling bit to said
tubular body whereby rotation of said tubular body in one direction
rotates said drilling bit and when said tubular body is
non-rotatably supported said drilling bit may be rotated relative
to said tubular body;
electrical means internally of said tubular body for the rotation
of said drilling bit relative to said tubular body;
electrical means within said tubular body of varying the angle of
the drilling axis of said drilling bit relative to said tubular
body; and
an electrical connector means within said tubular body adjacent the
upper end thereof, said electrical connector means adaptable to
removably receive electrical connection with means lowered in said
drill string for selectably energizing said means of rotation of
said drilling bit and said means of varying the angle of said
drilling bit.
2. A drilling tool including provision for changing the direction
of drilling of a borehole according to claim 1 wherein said tubular
body is in the form of a plurality of segments each connected to
the other by a swivel means, the lowermost segment having said
drilling bit extending therefrom and the uppermost segment having
said drill string attachable thereto.
3. A drilling tool including provision for changing the direction
of drilling of a borehole according to claim 1 wherein said
drilling bit includes an upwardly extending reduced diameter
portion within said tubular body, said upwardly extending portion
being coaxial with said drilling bit drilling axis, and wherein
said means of varying the angle of the drilling axis of said
drilling bit relative to said tubular body includes:
a positioning gear having an eccentric opening therethrough
rotatably receiving said drilling bit upwardly extending
portion;
an electric motor supported within said tubular body having a shaft
extending therefrom; and
a drive gear affixed to said shaft and in engagement with said
positioning gear.
Description
CROSS REFERENCE
This disclosure is not related to any pending United States or
foreign patent application.
BACKGROUND AND OBJECTS OF THE INVENTION
In borehole drilling it is frequently necessary to change the
direction of drilling. Such procedure is commonly utilized in the
petroleum industry to slant wells. By this means a borehole may be
started, for instance, adjacent a lake, river or other body of
water, with the lower terminus of the borehole being beneath the
body of water. Another example of the frequent application for
directional drilling is encountered in offshore drilling. Drilling
platforms are extremely expensive to move from one location to
another. By use of directional drilling techniques it is possible
to drill several wells from a drilling platform without moving the
platform. In addition to the petroleum industry, the solution
mining industry also has requirements for directional drilling,
especially high angle drilling, even from vertical to
horizontal.
At the present time the most frequently used technique for changing
the direction of a drill bit in a borehole is first, removing the
drilling string from the borehole, second, lower into the hole a
tool known as a whipstock, and third, reinsert the drilling string
into the borehole. The function of the whipstock is to divert the
direction of drilling and cause the drill bit to drill along a
drilling axis at an angle relative to the axis of the prior drilled
borehole. Such means of directional drilling is not completely
satisfactory since it is time consuming and therefore expensive.
Each time it is necessary to change drilling directions the drill
string must be removed, the whipstock lowered into position, and
the drill string reinserted. When drilling is resumed only a
preselected declination from the drilling axis of the original
borehole is obtained. Further change in the direction of drilling
requires the procedure to be repeated, each time requiring the
drill string to be completely removed and reinserted.
The primary object of this invention is to provide an improved
directional drilling tool.
More particularly, an object of this invention is to provide an
improved drilling tool including provisions for changing the
direction of drilling of a borehole by means controllable at the
surface of the earth without requiring the drill string having the
drilling tool attached thereto to be removed from and reinserted in
the borehole each time a drilling direction change is required.
These general objects, as well as more specific objects of the
invention, will be understood by reference to the description,
taken in conjunction with the attached drawings.
DESCRIPTION OF THE VIEWS
FIGS. 1A, 1B and 1C show an embodiment of the drilling tool of this
invention in cross section in three segments, FIG. 1A showing the
lowermost segment, FIG. 1B showing the middle segment, and FIG. 1C
showing the topmost segment.
FIGS. 2, 3 and 4 are cross-sectional views taken along the lines
2--2, 3--3 and 4--4 respectively, of FIG. 1A.
FIG. 5 is a cross-sectional view taken along the line 5--5 of FIG.
1B.
FIG. 6 is a cross-sectional view of the lowermost segment as in
FIG. 1A, but showing the relationship of the components of the
drilling tool when the tool is set to change the direction of
drilling.
FIG. 7 shows a borehole having a high degree of declination and
showing means of preventing a drill string from becoming stuck in
the borehole.
DETAILED DESCRIPTION
Referring first to FIGS. 1A, 1B and 1C, the directional drilling
tool includes four attached tubular housing sections, that is, a
drill housing 10A shown in FIGS. 1A and 1B; a motor housing 10B
shown in FIG. 1B; an instrument housing 10C shown in FIGS. 1B and
1C; and a connector housing 10D shown in FIG. 1C. The housing
portions are connected to each other by swivel socket portions
generally indicated by the numerals 12A, 12B and 12C.
Supported to the lower end of drill housing portion 10A is a drill
bit 14, which may be of the type customarily used in rotary
drilling. The drill bit is affixed to a shaft 16 and, although
shown integrally formed with the shaft the bit may be detachably
affixed to the shaft so as to provide easy removal and replacement.
Shaft 16 includes an enlarged diameter ball portion 16A which is
spherical in most of its exterior surface and is received in a
spherical socket recess 18A in the lower end 18 of drill housing
10A. Formed in the ball portion 16A, in a plane normal to the axis
of shaft 16, is a peripheral groove 20, and in like manner, formed
in the socket recess 18A is a circumferential groove 22. Positioned
between the enlarged ball portion 16A and the socket recess 18A, in
grooves 20 and 22, are balls 24A and 24B.
Referring to FIG. 2, groove 20, formed in shaft ball portion 16A,
is configured to provide opposed ball engaging projecting portions
26A and 26B. Contrarily, groove 22 formed in housing socket recess
18A has opposed tapered ball recesses 28A and 28B. When the housing
10A is rotated in the direction indicated by the upper arrow at the
top of FIG. 2, balls 24A and 24B lock against the projecting
portions 26A and 26B to rotate the shaft, and thereby the drill bit
14. However, with the housing 10A held in a stationary position,
shaft 16 is free to rotate in the same direction, as indicated by
the lower arrow, since the balls 24A and 24B are pushed back into
the ball recesses 28A and 28B. The purpose of this ratchet means
affording independent rotation of the shaft 16 will be described
subsequently.
The upper end of shaft 16 has affixed to it a universal coupling 30
which, in turn, is coupled to a telescoping shaft section 32, and
at its upper end is another universal coupling 34. Supported within
housing 10A above shaft 16 is a gear reducer 36 having an input
shaft 38 and an output shaft 40. The output shaft 40 is secured to
the upper universal coupling 34. Gear reducer 36 is supported in
housing 10A by plates 42 having openings 44 therein permitting
fluid flow within the housing past the gear reducer. Shaft 16,
including the ball portion 16A, is tubular, permitting fluid
flowing downwardly within the interior of housing 10A to flow out
through bit 14.
Above the ball portion 16A is a positioning gear 46 having an
eccentric opening 48 therein which rotatably receives shaft 16.
Opening 48 is contoured to permit shaft 16 to extend angularly
therethrough. Engaging positioning gear 46 is a drive gear 50
affixed to shaft 52 extending from positioning motor 54. A gear
reducer portion 54A may be included with positioning motor 54 so
that shaft 52 rotates relatively slowly when motor 54 is
energized.
Referring to FIG. 6 the drilling tool is shown in an attitude in
which the drilling axis 56 (that is, the axis of shaft 16) is at an
angle relative to the axis of housing 10A. That is accomplished by
energizing positioning motor 54 which rotates gear 50 and thereby
positioning gear 46. The eccentric opening 48 in positioning gear
46 causes shaft 16 to be pivoted about ball portion 16A. FIG. 3
shows the relationship of drive gear 50 and positioning gear 56.
Spacer 60 affixed to the interior of housing 10A retains gears 46
and 50, each in its rotational position.
The upper end of housing 10A (see FIG. 1B) has an integral ball
portion 62 which is received in a socket recess 64 formed in the
lower end of motor housing 10B. The ball portion 62 and socket
recess 64 form swivel socket 12A previously mentioned. The ball
portion 62 includes vertical slots 66 in the exterior surface which
slidably receives studs 68. The slots 66 and studs 68 permit a
pivotal or swivel relationship of housing 10A to 10B while
rotationally coupling the housings to each other.
Received in housing 10B is a drill drive motor 70 having a drive
shaft 72 extending from the lower end. Drive shaft 72 is attached
to the upper end of gear reducer input shaft 38 by means of a
universal coupling 74.
Drill drive motor 70 is supported in housing 10B by means of plates
76 having openings 78 therein permitting the flow of fluid in the
housing past the drive motor. The spherical portion 62 at the upper
end of drill housing 10A has opening 80 therethrough so that the
fluid flow may pass downwardly from housing 10B to housing 10A and
ultimately out through the shaft 16 and drill bit 14.
At the upper end of housing 10B and the lower end of housing 10C is
swivel socket 12B having the same configuration and serving the
same function as previously described with reference to swivel
socket 12A. That is, the upper end of housing 10B includes a ball
portion 82 received in a socket recess 84, with slots 86 and studs
88 as above described. OPening 89 in ball portion 82 allows flow of
fluid downwardly through socket 12B.
Supported in the lower portion of instrument housing 10C (see FIGS.
1B and 1C) is a pressure equalization chamber 90, held in position
by plates 92 having openings 94 therein. Extending between the
upper end of drill drive motor 70 and the lower end of pressure
equalizing chamber 90 is a flexible conduit 96 connecting the
interior of motor 70 with that of the pressure equalizing chamber
90. The function of equalizing chamber 90 is to prevent fluid
contamination of motor 70 through seals around shaft 72. The use,
purpose, and function of a pressure equalizing chamber with a
submerged motor operated to drive a pump is well known and such, of
and within itself, is not novel to this invention.
Positioned in the upper end of instrument housing 10C (FIG. 1C) is
an instrument package 98 supported by plates 100 having apertures
102 therein affording fluid flow externally of the package within
the housing. The instrument package 98 may include a variety of
instruments but typically houses a dip meter which indicates the
angle of declination of the borehole and a magnetic compass or flux
gate arrangement which provides means of indicating directional
orientation. Basically, a magnetic compass or flux gate arrangement
senses the direction of the earth's magnetic field and indicates
the direction of such field to the surface by means of conductors
104. The upper end of instrument housing 10C forms the swivel
socket 12C in the same manner as previously described for swivel
sockets 12A and 12B and includes ball portion 106, a socket recess
108 formed at the lower end of connector housing 10B, slots 110 and
studs 112. Opening 114 through the ball socket 106 provides free
fluid flow from connector housing 10D downwardly through instrument
housing 10C.
Positioned within housing 10D is a plate 116 having fluid flow
apertures 118 therein. Mounted on the plate 116 is a stab connector
male portion 120 which provides means for receiving a stab
connector female portion (not shown) lowered into the connector
housing 10D by means of a cable (not shown). Extending from the
connector portion 120, in addition to conductors 104 which
communicate with instrument package 98, are conductors 122 and 124
which connect to the positioning motor 54 and drill drive motor 70
respectively. For a description of a submergible electrical
connector which includes male portion 120 reference may be had to
U.S. Pat. No. 3,398,392. entitled "Submergible Electrical
Connector," issued Aug. 20, 1968.
At the upper end of connector housing 10D are threads 126 by which
the housing may be connected to the lower end of a tubular drill
string (not shown).
OPERATION
The directional drilling tool of this invention is used with
conventional drilling equipment. Prior to the depth at which it is
desired to change drilling direction of a borehole, the drill
string is brought to the surface and, in place of the regular drill
bit, the drilling tool of this invention is secured to the drill
string by means of threads 170 at the upper end of the connector
housing portion 10D. The tool is then lowered into the borehole.
Drilling can be continued in the normal way until the depth at
which a deviation in direction of drilling is required. Rotation of
the connector housing 10D by means of a drill string rotates the
other housing portions 10C, 10B and 10A due to the non-rotatable
but flexible connections between housing portions. Rotation of the
drill housing 10A, in the direction of the upper arrow as shown in
FIG. 2, causes the rotation of the shaft portion 16 and thereby
drill bit 14 as previously described.
When it is desired to change drilling direction the drill string is
lifted slightly so that pressure is taken off the bit 14. By means
of a cable the upper portion of a submergible electrical connector
is lowered through the drill string and into the upper end of
connector housing 10D where the connector 120 is engaged. This
connection provides continuity with conductors 104, 120 and 124 to
the earth's surface. Instruments within package 98 conduct
information by way of conductor 104 and connector 120 to the
earth's surface identifying the orientation of the drilling tool
relative to the earth's magnetic field. The drill string and the
drilling tool may be rotated to change the orientation as
required.
By means of electrical signal from the earth's surface, conveyed by
way of connector 120 and conductor 122, positioning motor 54 is
energized rotating drive gear 50 and thereby positioning gear 46.
This rotation changes the drilling axis 56 relative to the axis 58
of drill housing 10A. The amount of declination depends on the
length of time motor 54 is energized, within the limit of the
maximum declination provided by the amount of eccentricity of
opening 48 in positioning gear 46.
After the desired drilling declination angle is obtained the drill
string may be lowered so that bit 14 engages the bottom of the
borehole.
Energy may then be supplied by way of connector 120 and conductor
124 to drill drive motor 70. The rotation of shaft 72, gear reducer
input shaft 36, and gear reducer output shaft 40 causes the
rotation of shaft 16 and drill bit 14. During this time the drill
string and therefore the directional drilling tool housing is held
non-rotational but is allowed to move downwardly as bit 14
advances. The drilling operation can continue for a length of time
sufficient that the borehole extension is established at the
selected angle of deviation. At this time the borehole can be
checked for dip and direction to see if the desired angle has been
attained.
After the borehole is drilled sufficiently by means of motor 70 to
positively establish a new direction of drilling, positioning motor
54 is energized to return shaft 16 to its normal position in which
the axis 56 of the shaft is coincident with the axis 58 of body
portion 10A. The cable with the removable connector portion is
removed, disconnecting from connector 170. Conventional drilling
may then be resumed by means of rotation of the drill string
causing the rotation of the drilling tool and bit 14. Conventional
drilling may continue as long as desired and when it is necessary
to again change the direction of drilling the above described
procedure is repeated, that is, the rotation of the drill string
and thereby the tool is stopped, the drill string is lifted
slightly, the cable is run within the drill string to establish
connection with connector 120, a new angle of direction of drilling
is selected by energization of positioning motor 54, followed by
drilling by means of drill drive motor 70 to establish the new
drilling direction. Thus, the change of direction of drilling may
be repeated as many times as desired, limited only to the life of
bit 14, without removing the drill string and drilling device from
the borehole and requiring only the running of a cable supported
connector into and out of the drill string each time a new
direction of drilling is desired.
It can be seen that by use of this invention a borehole may be
drilled at a very high degree of declination relative to he
vertical, even to the extent of changing drilling from a vertical
to a horizontal direction. Only a small degree of angular deviation
can achieve an ultimate change from vertical to horizontal. The
housing of the directional drilling tool is formed in sections 10A,
10B, 10C and 10D to permit drilling of much shorter radius curves
than would otherwise be possible if all of the elements were housed
in a single enclosure.
One problem which has existed in the drilling industry with
directional drilling is that continuous wear along the inside
curves of a borehole deviation results in the formation of a recess
having approximately the same diameter as the drill string. When
attempt is made to remove the drill string it is not uncommon for
the drill string collars to be caught in this recess and make it
difficult, if not occasionally impossible, to remove the drill
string. Such phenomena is referred to in the industry as a "key
seat." An arrangement is shown in FIG. 7, which may be utilized, to
prevent the formation of a key seat. Casing, in the form of joints
128 held together by couplings 130, is positioned in the curved
portion 132 of a borehole. After the casing 128 is in position
fluid cement is run through the casing to flow out the lower end
and upwardly within the borehole 32, the cement 134 solidifying and
serving to hold the casing 128 in position. As the borehole is
extended past the portion 132 wherein declination takes place the
drill string rotates in the interior of casing 128 which, being
much harder and more resistant to abrasion than most earth
formations, prevents a key seat from forming. The casing 128 may be
regular casing as presently utilized in the petroleum industry if
the borehole curve is of a large radius and more flexible casing
can be used if the curve is of a smaller radius. "Cement" as used
herein means any material which can be pumped in liquid form and
which solidifies after a given time.
It is to be understood that the invention has been described by
reference to a structural embodiment shown for purposes of
exemplifying the invention only. Obviously, many alternate means
may be utilized to provide the slip arrangement between the shaft
16 and drill housing 10A. Other devices may be utilized to provide,
upon the application of an electrical signal, the declination of
the axis of shaft 16 other than by the use of motor 14, gear 50 and
gear 46 as shown. The arrangement and placement of the drilling
motor 70, gear reducer 36, pressure equalizing chamber 90,
instrument package 98, and so forth, may change considerably, all
within keeping of the invention. The specific details of
construction of the universal couplings 30, 34 and 74 are exemplary
only of many other types of universal couplings which may be
utilized.
Drill drive motor 70 is shown and described as being an electrical
motor. An alternate arrangement would include the use of a
hydraulic motor. While a male connector portion 120 is shown,
adaptable to receive a female connector portion, it can be seen
that connector portion 120 may be a female portion adapted to
receive a male portion lowered downwardly into the upper end of
connector housing 10D.
While the invention has been described with a great degree of
particularity it is manifest that many changes may be made in all
parts of the apparatus without departing from the spirit and the
scope of the invention. The invention is not to be limited to the
apparatus described but is to be limited only by the scope of the
attached claim or claims, including the full range of equivalency
to which each element or step thereof is entitled.
* * * * *