U.S. patent number 3,908,771 [Application Number 05/447,371] was granted by the patent office on 1975-09-30 for drill collar incorporating device for jetting drilling fluid transversely into bore hole.
Invention is credited to Wylie P. Garrett.
United States Patent |
3,908,771 |
Garrett |
September 30, 1975 |
Drill collar incorporating device for jetting drilling fluid
transversely into bore hole
Abstract
A self-stabilizing drill collar structure for incorporation into
a drill string for deep well rotary drilling includes an elongated
cylindrical collar member having an axially extending throughbore
for passing drilling fluid downwardly to the lower end of the drill
string. An arrangement of easily replaceable and non-fouling
nozzles located within slots and protected by the wall of the
collar serve to divert clean downwardly flowing drilling fluid from
the axial throughbore and discharge it in a jet-like manner
laterally outward from the opposite ends of the slots into the
annular gap between the collar and bore hole to thereby improve
lubrication of the gap and provide better circulation and return of
the drilling fluid to the surface for re-cycling, and which enables
the drilling to take place at a higher speed and with greater
accuracy and stability as regards the desired course of the bore
hole. The number of nozzles in operation can be varied as desired
by replacing one or more of them with plugs and the collar member
can also be provided optionally with reaming flanges to shape the
bore hole.
Inventors: |
Garrett; Wylie P. (Hammond,
LA) |
Family
ID: |
23776110 |
Appl.
No.: |
05/447,371 |
Filed: |
March 1, 1974 |
Current U.S.
Class: |
175/393; 175/65;
175/325.2; 175/406; 175/424 |
Current CPC
Class: |
E21B
17/16 (20130101); E21B 21/00 (20130101); E21B
17/1078 (20130101); E21B 10/26 (20130101); E21B
10/60 (20130101) |
Current International
Class: |
E21B
21/00 (20060101); E21B 10/00 (20060101); E21B
10/60 (20060101); E21B 17/00 (20060101); E21B
17/16 (20060101); E21B 17/10 (20060101); E21B
10/26 (20060101); E21C 015/00 () |
Field of
Search: |
;175/393,406,422,324,325,320,207,60,65,100,231,317,316,339,340,344,267 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Abbott; Frank L.
Assistant Examiner: Favreau; Richard E.
Attorney, Agent or Firm: Pierce, Scheffler & Parker
Claims
I claim:
1. A drill collar structure for incorporation into a drill string
for deep well rotary drilling comprising an elongated cylindrical
collar member having an axially extending throughbore for passing a
drilling fluid downwardly to the lower end of the drill string,
said collar member including at least one slot forming a duct
extending transversely through the wall thereof intermediate said
throughbore and its periphery, opposite ends of said slot reaching
to the surface of said collar member at corresponding locations on
the periphery thereof, and at least one nozzle member located in a
bore extending transversely between said throughbore and said slot
intermediate the ends of said slot for jetting drilling fluid
diverted from said throughbore into said slot and thence outwardly
from the opposite ends thereof into the bore hole.
2. A drill collar structure as defined in claim 1 wherein each slot
is provided with a plurality of nozzle members arranged in spaced
relation in the longitudinal direction of the collar.
3. A drill collar structure as defined in claim 1 wherein the
transverse bore in which said nozzle member is received extends in
a radial direction and intersects the slot at the middle
thereof.
4. A drill collar structure as defined in claim 1 and which is
incorporated into the drill string at the bottom thereof to serve
as a pilot, one end of said collar having the drill bit secured
thereto and the opposite end thereof being provided with means for
connection to the adjoining end of the next-above section of the
drill string.
5. A drill collar structure as defined in claim 1 and which is
provided with connection means at each end thereof for
incorporation into the drill string above the lowermost section
mounting the drill bit.
6. A drill collar structure as defined in claim 1 and which
includes a plurality of said slots and nozzle members therein
spaced longitudinally along the collar member.
7. A drill collar structure as defined in claim 1 which includes a
plurality of said slots and nozzle members associated therewith
disposed symmetrically about the axis of the collar.
8. A drill collar structure as defined in claim 7 which includes
two of said slots and nozzle members associated therewith located
symmetrically to opposite sides of the collar axis.
9. A drill collar structure as defined in claim 1 wherein said
nozzle member includes an externally threaded barrel portion
engageable with an internally threaded portion of said transverse
bore thereby to facilitate installation and removal of said nozzle
member.
10. A drill collar structure as defined in claim 9 and which is
also provided with a threaded plug for use in lieu of a threaded
nozzle to close off said transverse bore and block flow of drilling
fluid therethrough when jetting action is not desired.
11. A drill collar structure as defined in claim 1 and wherein said
collar member is provided with flanges extending radially at the
location of said slots for effecting a reaming action to shape the
bore hole.
12. A drill collar structure as defined in claim 11 wherein said
reaming flanges are arranged in uniform spaced relation around the
periphery of the collar member and include apertures therethrough
from one side to the other for reducing the turning resistance of
the collar through the annular column of drilling fluid which is
returned to the surface in the annular space between the drill
collar and the bore hole.
Description
The present invention relates to the art of drilling deep wells. In
the rotary method of deep drilling it has been customary to include
one or more drill collars in the drill string above the drill bit.
A drill collar is a rather heavy rigid member, or a string of such
members connected end-to-end above the drill bit for lending weight
and rigidity to the drill string and through its pendulum effect
serves to reduce deflection of the bit axis and thereby stabilize
and prevent the lower end of the string from deviating from a
vertical course. The collars, which are tubular to permit downward
passage of drilling mud from the surface through the string to the
drill bit, are usually made in sections of various length, e.g.
about 40 ft. each, and may extend to a height of several hundred
feet above the drill bit depending upon particular
circumstances.
Extensive deviation from the vertical is to be avoided for
otherwise it may result in a failure to penetrate the desired
geological structure. It may also lead to sticking of the drill
string in the bore hole, as well as an increase in fatigue failure
of pipe section connections due to cyclic stresses generated as the
drill string rotates in the crooked hole. It may also complicate
the installation of casing and other equipment required to complete
the well and may also give rise to later problems such as excessive
wear on sucker rods used to actuate the pump in the well. In some
cases, extensive deviation may also lead to violations with respect
to well spacing, proximity of the bottom of the bore hole to lease
lines, and the like.
It has also been proposed to provide measures for facilitating
return circulation of drilling mud from the drill bit area in the
annular space between the drill string and the wall of the bore
hole. These include the use of jets which discharge drilling mud
from the interior of the drill string into the bore hole at one or
more locations above the drill bit and which may be designed, for
example, as disclosed in U.S. Pat. Nos. 2,805,043 and 2,765,146 to
provide an upward lift to the returning mud and reduce hydrostatic
pressure below the jets.
The principal object of the present invention is to provide an
improved self-stabilizing drill collar, or a series of such
collars, at the lower end of the drill string for producing
straighter bore holes, improved lubrication and with an improved
jet action to provide for better circulation and return flow of
drilling mud. The improved collar structure also enables the drill
string to be rotated at a higher speed than heretofore possible
thus resulting in a corresponding speed-up in cutting action at the
drill bit which is reflected by a reduction in drilling costs.
One feature of the improved drill collar structure is an improved
arrangement of non-fouling nozzles located within and protected by
the wall of the collar for discharging i.e. jetting downwardly
flowing drilling mud laterally from the bore in the collar into the
annular gap between the periphery of the collar and the surface of
the bore hole. This lateral discharge of clean drilling mud from
the collar into the bore hole serves to lubricate the gap and
thereby reduces any tendency for build-up of undesirable
counter-torque forces that increase stress in the drill string and
reduce its turning speed.
A further feature of the improved drill collar structure is that
the nozzles for jetting drilling mud into the annular gap between
the collar and the surface of the bore hole are housed within slots
extending through the wall of the collar parallel with the axis of
the drill string, whereby the main blasting force of the mud as it
leaves the nozzle is attenuated somewhat by the time it is
discharged from the opposite ends of the slot thus minimizing the
possibility of making wash cuts in the surface of the bore hole
which are undesirable since they increase the amount of drilling
mud lost in the bore hole as it returns upwardly to the surface for
cleaning and re-cycling. By locating the nozzles within the slots
they thus become protected from fouling by particulate matter
entrained in the upwardly returning drilling mud, such as shale,
rock or other earth chips or other solid matter.
A further feature of the improved drill collar structure is that it
can include radially extending reaming flanges that serve to shape
the bore hole and cut away any solid obstructions such as rock that
may project therein, these flanges being provided with apertures to
reduce its turning resistance through the annular column of the
returning drilling mud.
Still another feature of the improved drill collar structure is
that the nozzles, which are preferably made from stainless steel or
monel, may be easily screwed into place within the slotted portion
of the collar wall thus making it possible to easily increase or
decrease the number of nozzles in the slot, the nozzles which are
removed being replaced by threaded solid plugs, which plug up the
threaded openings into which the nozzles are normally screwed.
The foregoing as well as other objects and advantages inherent in
the invention will become more apparent from the following detailed
description and the accompanying drawings wherein:
FIG. 1 is a vertical section through the lower portion of a bore
hole being drilled into the earth by a drill bit secured to the
lower end of a rotatable string of drill pipe and which is supplied
with drilling mud under sufficient pressure to carry the cuttings
to the top of the bore hole in the annular gap formed between the
latter and the drill pipe, the pipe section at the bottom end of
the string being constituted by a drill "collar" which is provided
along the length thereof with jetting devices in accordance with
the invention;
FIG. 2 is view illustrating a collar structure similar to FIG. 1,
one or more of which may be incorporated in the drill string by
tool joints, as in conventional practice, above the collar shown in
FIG. 1 to provide jetting action at any desired higher locations
along the drill string;
FIG. 3 is a partial central longitudinal section through the collar
structure depicted in FIG. 1 but drawn to a larger scale, the view
being taken on line III--III of FIG. 4;
FIG. 4 is a transverse section taken on line IV--IV of FIG. 3;
and
FIGS. 5 and 6 are views partly in section of the nozzle and plug
structures per se drawn to an even larger scale.
With reference now to the drawings, FIG. 1 depicts the lower end of
the bore hole 1 in the earth 2 in which a drill string is located,
the drill string being composed of the required number of drill
pipe sections, not shown, coupled together by tool joints in
accordance with conventional practice in drilling deep holes. The
lower end of the drill string terminates in a tubular drill collar
3 to the lower end of which is secured a drill bit 4. As will
become readily apparent hereinafter, the particular drill collar
structure depicted in FIG. 1 is a combined unit which functions
both as a pilot to guide the drill as well as a device for also
jetting drilling fluid transversely from the collar into the bore
hole. The upper end of the collar 3 terminates in a tapered
threaded socket 5 for coupling onto a complementary threaded
tapered plug 5a of the next-above section of the string. This may
be a plain pipe section or it may be another collar in accordance
with the invention, as depicted in FIG. 2, when one or more such
collar structures are desired to be incorporated in the drill
string above the bit.
The drill string is rotated from above ground and a drilling fluid
commonly known as mud is pumped into the upper end of the drill
string for flow downwardly through the bore to the bit 4 to cool it
and also wash the cuttings to the top of the bore hole, the
drilling mud moving upwardly in the annular gap 6 between the bore
hole 1 and collar 3 as well as the other such collars or plain pipe
sections located above this collar to the surface where it is
cleaned and re-cycled. The flow path of the mud is indicated by
directional arrows.
The drill collar 3 is provided with an arrangement of elongated
slots 7 forming ducts extending through the wall of the collar
parallel to the axis of drill string in which are located one or
more nozzles 8, see FIGS. 3 and 4, for jetting drilling mud into
the gap between the collar and bore hole. Location of the nozzles
within the slots 7 protects them from contact by any solid matter
entrained in the upward return flow of drilling mud such as shale,
small rocks, earth chips and cuttings made by the drill bit and
hence prevents the nozzles from fouling and plugging up. Moreover,
the main blasting force of the mud as it leaves the nozzles is
somewhat attenuated by the time it leaves the opposite ends 7a, 7b
of the slots thus minimizing the possibility of making wash cuts
into the surface of the bore hole which are undesirable since they
increase the amount of the comparatively expensive drilling mud
lost in the bore hole during its return flow to the surface.
In the particular embodiment illustrated in FIGS. 1, 3 and 4, a
pair of such slots 7 each with two longitudinally spaced nozzles 8
are located symmetrically on opposite sides of the axis of the
drill collar, one pair of slots being located towards the upper end
of the collar and another pair of slots towards the lower, bit end
of the collar which can have an overall length of up to 40 feet,
for example. However, other arrangements of these slots and nozzles
with respect to number and location are possible and hence the
depicted embodiment is to be regarded as typical rather than
limitative.
Each nozzle 8, as shown most clearly in the larger scale view of
FIG. 5 includes an externally threaded barrel portion 9 which is
adapted to be screwed into a threaded bore 10 which, as shown in
FIGS. 3 and 4, extends transversely through the wall of the collar
from the axial through bore 11 to the slot 7. The barrel portion 9
terminates in an opening 12 of restricted diameter which forms the
nozzle per se and through which clean drilling mud is jetted into
slot 7, the blasting force of the jet being somewhat attenuated as
it divides at the center of the slot and flows in opposite
directions to the opposite ends 7a, 7b from which it is discharged
into the annular gap 6 to lubricate the latter and thus reduce any
tendency for build-up of undesirable counter-torque forces that
increase stress in the drill string and reduce its speed as well as
sometimes result in breakage of the string.
The nozzle opening 12 is located in a head portion 13 which is
preferably hexagonal or some other polygonal configuration to
receive a wrench for screwing in or removing the nozzle structure
8, and a washer 14 is seated between the underside of the head 13
and the surface of slot 7 to establish a seal.
If fewer nozzles are desired, solid plugs 15 as shown in FIG. 6
having identical exterior dimensions as the nozzles 7 may be
screwed in to replace one or more of the latter.
The drill collar 3 is also seen to include, as an optional feature,
a plurality of radially extending flanges 16, for example, three
arranged in uniformly spaced relation around the periphery of the
collar. The opposite ends 16a of these flanges can be tapered as
indicated in FIGS. 1 and 3 and are provided with a plurality of
apertures 17 to reduce its turning resistance through the annular
column of drilling mud being returned to the surface. The flanges
16 perform a reaming function to shape the bore hole and cut away
any solid obstructions such as rock that may project into it.
The collar structure depicted in FIG. 2, as previously explained is
not associated with the drill bit as in FIG. 1 but has the same
arrangement of slots, nozzles and reaming flanges and along with
one or more others like it is intended to be incorporated into the
drill string above the drill bit when deemed desirable to provide a
transverse jetting action in the bore hole farther upwards along
the string.
While the nozzle structures 8 are preferably made in such manner as
to enable them to be easily removed for exchange, or replacement
with solid plugs, a permanent type of nozzle installation within
the body of the drill collar is obviously possible.
Also, the novel collar structure which functions both as a drill
guide and jetting device can be combined in the drill string with
other drill collars or drill tools of a less caliber or design.
* * * * *