U.S. patent number 3,724,862 [Application Number 05/175,153] was granted by the patent office on 1973-04-03 for drill head and sealing apparatus therefore.
Invention is credited to Morris S. Biffle.
United States Patent |
3,724,862 |
Biffle |
April 3, 1973 |
DRILL HEAD AND SEALING APPARATUS THEREFORE
Abstract
A drill head assembly for use in oil drilling operations in
which there is provided a rotatable packing means for preventing
abrasive well fluids or vapors from contacting the bearing surfaces
of the rotatable portion of the drilling head and for preventing
the escape of well fluids or vapors into the atmosphere. The
packing means is constructed such that packing becomes tighter as
the well pressure increases, thereby performing the function of a
final control in the event of a blowout and is also constructed
such that repacking may be performed externally to the drilling
head without disassembly of the drill head or any of the rotatable
parts therein.
Inventors: |
Biffle; Morris S. (Vermilion,
OH) |
Family
ID: |
22639142 |
Appl.
No.: |
05/175,153 |
Filed: |
August 26, 1971 |
Current U.S.
Class: |
166/84.3;
277/324; 277/510; 277/562 |
Current CPC
Class: |
E21B
33/085 (20130101); F16J 15/185 (20130101) |
Current International
Class: |
F16J
15/18 (20060101); E21B 33/08 (20060101); E21B
33/02 (20060101); F16j 015/16 (); E21b
033/00 () |
Field of
Search: |
;277/31,71,3,4 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Rothberg; Samuel B.
Claims
What is claimed is:
1. A drill head having an annular chamber formed therethrough for
the reception of a rotating driving member used in the drilling of
wells, comprising:
an annular sleeve;
a first annular housing adapted to concentrically receive said
annular sleeve, thereby forming a chamber between said annular
sleeve and said first annular housing;
bearing means disposed within said chamber such that said annular
sleeve is rotatable;
a second housing adapted to receive said first annular housing and
said annular sleeve in a manner such that an annulus is formed
between said annular sleeve and said second housing;
packing means adapted to be positioned in said annulus;
means for applying pressure on said packing means in a first
direction thereby forming a rotating hermetic seal between said
annular sleeve and said second housing;
means for capping the upper extremity of said drill head, said
means adapted to receive said driving member and further providing
a seal preventing the egress of any existing well fluids via the
upper extremity;
means for directing any internal forces generated by said well onto
said packing means in a second direction further insuring a
hermetic seal to exist between said annular sleeve and said second
housing;
2. A drill head according to claim 1 wherein said annular sleeve
and said second housing have a clearance formed therebetween such
that said annular sleeve is rotatable independently of said second
housing.
3. A drill head according to claim 2 wherein said first annular
housing and said second housing are stationery.
4. A drill head according to claim 3 wherein said clearance is
formed between the lower extremity of said annular sleeve and the
upper extremity of said second housing.
5. A drill head according to claim 4 wherein said second housing
includes a wash pipe such that when said second housing receives
said first annular housing, the outside wall of said wash pipe and
the inside wall of said annular sleeve define said annulus.
6. A drill head according to claim 1 in which said first annular
housing comprises an annular tube terminated at each end with a
flange.
7. A drill head according to claim 6 in which said bearing means
comprise tapered roller bearings having both radial and thrust
capabilities.
8. A drill head according to claim 1 wherein said means for
directing any generated internal forces onto said packing means
comprises an annular groove formed on the bottom end of the annular
sleeve, said annular groove being connected to a plurality of
inlets, said inlets being in communication with the annular chamber
formed through said drill head.
9. A drill head according to claim 1 wherein said packing means
comprises an annular gland, wherein said annular gland has an
inside diameter greater than the outside diameter of said wash pipe
and positioned such that it encircles a portion of said second
housing at the upper extremity thereof and is capable of
longitudinal movement about said wash pipe.
10. A drill head according to claim 9 wherein said means for
applying pressure on said packing means is provided by said annular
gland having a shoulder formed thereon, said shoulder being of a
dimension and size such that said annulus formed between said
annular sleeve and said second housing being adapted to receive
said shoulder.
11. A drill head according to claim 10 wherein said annular gland
is threadedly affixed to the lower extremity of said annular
sleeve.
12. A drill head according to claim 1 wherein said means for
capping comprises an elongated resilient steel reinforced mass
having an opening therethrough along the longitudinal axis thereof
for the reception of said rotating driving member, the exterior of
said resilient mass being tapered inwardly in a downwardly
direction, said means for capping thereby providing a constrictive
seal about said driving member extending therethrough and insuring
a tighter seal upon the application of any pressurized fluids
thereto, said mass retained on said annular sleeve by compression
means.
13. A drill head according to claim 1 wherein said second housing
further includes a side outlet tube for the egress of well fluids,
cuttings and the like.
14. A drill head having an annular chamber formed therethrough for
the reception of a rotatable driver member, such as a kelley, for
use in conventional and pressure well drilling, comprising:
a first stationery housing including a tubular projection at the
upper extremity thereof and also including an outlet tube for the
egress of well fluids, cuttings and the like, said stationery
housing having means for affixing same to a well casing;
a second stationery housing, adapted for mounting on said first
stationary housing;
a rotatable sleeve member concentrically disposed within said
second stationery housing, said second stationery housing adapted
for mounting on said first stationery housing thereby forming an
annulus between said sleeve member and said tubular projection;
bearing means interposed between said rotatable sleeve and said
second stationery housing;
means for lubricating said bearing means;
packing means positioned in said annulus;
an adjustable gland to regulate the compression of said packing
means in a first direction thereby forming a rotating hermetic seal
between said rotating sleeve and said tubular projection, said
adjustable gland being in fixed relationship with said rotatable
sleeve;
capping means for the upper extremity of said rotating sleeve
member, said capping means adapted to receive a driving member and
further providing a seal between said drill head and said driving
member;
means for compressively holding said capping means with said
rotatable sleeve, and
means for directing any internal well pressures onto said packing
means in a direction opposing said first direction thereby
resulting in the expansion of said packing means, further
tightening said hermetic seal.
15. A drill head according to claim 14 wherein said means for
directing any internal well pressures onto said packing means
comprises an annular groove formed on the bottom edge of said
rotatable sleeve, said annular groove positioned immediately
adjacent the upper portion of said packing means and said annular
groove being further connected to a plurality of inlets, said
inlets being in communication with any generated well
pressures.
16. A drill head according to claim 15 wherein said adjustable
gland has an inside diameter greater than the outside diameter of
said tubular projection and positioned such that said gland
encircles said tubular projection and is adjustably affixed to said
rotating sleeve and is rotatable therewith.
17. A drill head having an annular chamber formed therethrough in
communication with any existing well pressures, said annular
chamber adapted to receive a rotatable driver member for use in
conventional and well drilling operations, comprising:
a first stationery housing including a hard smooth tubular
projection at the upper extremity thereof, said first stationery
housing further including an outlet for the egress of internal well
wastes and also including means for affixing said stationery
housing to a well casing;
a second stationary housing adapted for mounting on said first
stationary housing;
a sleeve member rotatable disposed within said second stationery
housing wherein an annulus is formed between the inside surface of
a shoulder formed on the lower extremity of said sleeve member and
the outside surface of said tubular projection when said second
stationery housing is mounted on said first stationery housing;
packing means concentrically positioned in said annulus;
an adjustable gland to regulate the compression of said packing
means in a first direction thereby forming a rotating hermetic seal
between said rotating sleeve member and said tubular projection,
said adjustable gland being in fixed relationship with said
rotatable sleeve and having an inside diameter greater than the
outside diameter of said tubular projection and positioned such
that said gland encircles said tubular projection and is adjustably
affixed to said rotating sleeve;
capping means for the upper extremity of said rotating sleeve
member, said capping means adapted to receive a driving member and
further providing a seal between said drill head and said driving
member;
means for holding said capping means in compression with said
rotatable sleeve member, and
an annular groove and a plurality of inlets formed on the bottom
edge of said sleeve member, said annular groove being connected to
said inlets, said inlets being in communication with the well
chamber whereby any generated forces are directed through said
inlets to said groove and applied directly to said packing means by
said groove, said forces being directed onto said packing means in
a direction opposing said first direction.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a drill head with rotatable packing means
contained therein for forming a tight packing between the rotatable
and non-rotatable sections of the drill head, this apparatus is
particularly useful for use with a rotary table of the type used in
oil well drilling operations.
2. Description of the Prior Art
Drill heads for use in oil well drilling operations are well known.
Generally, oil well drilling is presently accomplished by rotary
drilling. This includes a rotary table for driving a rotatable
member referred to as a kelley via well known driving means such as
a non-circular bushing referred to in the industry as a kelley
bushing. Attached to one end of the kelley is a drill pipe section
which is lowered into the earth by the kelley and rotated by the
kelley bushing during the drilling. At a time when drilling has
progressed as far as the kelley permits, the drill pipe section is
raised and another drill pipe section is attached to the previously
attached drill pipe forming what is commonly referred to as a drill
string. The drill string in turn is reattached to the kelley
whereupon drilling may be resumed.
One inherent disadvantage in this type of drilling is the problem
of keeping the abrasive well fluids for contacting the rotating
portions of the drilling apparatus. This problem is further
compounded by the internal pressures of the well fluid, which can
be great, particularly when a blowout occurs. The forces generated
by the internal well pressures tend to find an exit which provides
the path of least resistance. Hence, it is very necessary to
prevent the fluids which are sometimes at tremendous pressures from
contacting the oil and grease seals and bearings.
There has been much activity in the designing of apparatus which
minimizes the aforementioned problem. One such patent, U.S. Pat.
No. 2,303,090, issued to Pranger, takes the problem into
consideration. However, the structure described in that patent
appears to be a rather complicated mechanical structure which would
inherently add to the initial cost and would also add to the
maintenance costs, a serious consideration which must be borne by
those in the field. The need which exists in the industry is for
apparatus which is mechanically simple and relatively inexpensive
to maintain. Such apparatus is what the instant invention is
concerned with.
Other patents which are representative of apparatus designed to
prevent or minimize the aforementioned problem are U.S. Pat. Nos.
2,853,274 issued to Collins, 2,904,357 issued to Knox, 3,387,851
issued to Cugini, 3,400,938 issued to Williams. One feature which
is common to all of the above identified patents is their relative
complexity. In none of these patents is there a design wherein the
new packing may be placed in the sealing chamber externally, thus
obviating a major disassembly, nor can packing be replaced without
removing the entire string of drill tools from hole, nor does the
prior art disclose a design wherein the bearing and sleeve assembly
can be removed from the body of the drilling head to provide access
to the packing assembly without having to disassemble the bearing
assembly. e.g., in Knox, it is necessary to pull both the bearing
assembly and the lower seal together out of the drilling head in
order to obtain access to the lower seal.
Applicant not only provides such an apparatus, but also provides an
apparatus in which this may be accomplished external to the
drilling head. Applicant further provides an apparatus which is
mechanically simple, easy to maintain yet producing superior
results in preventing abrasive well fluids from contacting any
rotatable parts.
SUMMARY OF THE INVENTION
The present invention relates to a drill head for use in rotary
drilling operations.
The applicant having taken into account the problems which have
been encountered in the past, has designed a packing which is
positioned between the rotating and stationary members of the drill
head and which will prevent debris, abrasive well fluid from
contacting any of the rotatable mechanical sections of the drill
head. The instant invention is one solution to the problem. The
design of the drill head along with the packing means prevents any
debris, whether it be fluid, vapor or dry, airborne or whatever,
from passing through the grease seals and contacting the rotating
sections. Further, because of the inherent design of the instant
invention, any debris which might be blown out would be directed
out into the atmosphere away from the grease seals, bearings, ect.
The packing means utilized herein are self energizing, i.e., if the
internal well pressure increases, the packing means gets
proportionally tighter by utilizing the forces generated by the
well pressures.
The drill head consists basically of a lower assembly and an upper
assembly. The lower assembly is stationery and is usually mounted
on a blowout preventer or well casing. It further provides a side
outlet for the egress of debris formed by the cuttings and the
various drilling muds and lubricants used in the drilling
operation. The lower assembly also has formed therein a tubular
projection finished in a smooth hard chrome finish, usually
referred to as a wash pipe. This tubular projection may or may not
be made integral to the lower assembly. For purposes of this
specification, it is assumed to be integral to the lower housing,
although it would just as easily be a separate unit and threadedly
affixed thereto. A gland is positioned over the wash pipe and is
capable of longitudinal movement thereon.
The upper housing includes a housing in which is positioned a
rotating sleeve, which is also referred to in the trade as a
rotating bowl. Interposed between the housing and sleeve are the
necessary bearings and lubricating means. The upper housing is
positioned on the lower housing and because of the inherent design
of the apparatus, an annular space is formed between the outside
surface of the projecting wash pipe and the inside surface of the
rotating sleeve. Into this annular space is positioned the packing
material which is used for the sealing means. Pressure is applied
on the packing by the longitudinal drawing of the gland into the
annular space. Means are provided on the bottom of the rotating
sleeve for retaining the gland in fixed relation thereto such that
the gland rotates with the rotating sleeve. A seal is formed when
enough pressure is applied on the packing means by the adjustable
gland. This seal becomes a rotatable seal when the sleeve is given
rotation by some driver.
Also provided in this invention are means for further securing a
seal, particularly in the event of a blowout. There is provided on
the bottom edge of the sleeve an annular groove connected to the
well opening by a plurality of inlets. The annular groove opens up
directly above the packing material. Thus any pressures existing in
the well will be directed immediately on top of the packing
material via the inlets and annular groove. This direction is in
direct opposition to the pressure directed by the gland resulting
in the horizontal expansion of the packing material thereby further
increasing the seal. Naturally, in the event of a blowout, rotation
of the sleeve should be halted because of the increased pressure
being applied to the packing means, thereby increasing the friction
between the packing and the wash pipe, otherwise the packing
material would quickly be destroyed by the combined friction and
heat caused by rotation.
It will on occasion be necessary to replace the packing material
because of wear and tear. This presents no problem since all that
is required with this invention is dropping, i.e., lowering, the
gland and inserting the new packing. It is not necessary to
disassemble the drill head nor is it necessary to pull out the
drill string. Another important feature is the fact that the
insertion of new packing may be done externally to the drill
head.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a view of the drill head shown in cross section.
FIG. 2 is an enlarged crossectional view taken of the upper drill
head assembly.
FIG. 3 is an enlarged crossectional view taken of one portion of
the wash pipe and packing gland follower.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 illustrates a drill head 10 comprising a lower assembly 12
and an upper assembly 14, which is the subject of the present
invention. The drill head 10, in operation, is mounted to the upper
end of a well casing (not shown) or mechanical blowout preventers
by conventional means such as a mounting flange 16. In the
operation of the invention, a kelley (not shown) is passed
downwardly through the drill head 10, the drill string being
attached to the kelley. Attached to the mounting flange 16 is a
lower housing 18 which may be attached to the mounting flange 16 by
means such as welding. The lower housing 18 is provided on its
exterior walls, for reinforcement, with a plurality of mounting
struts 20 which are attached to a flange 22. The flange 22 contains
a plurality of holes bored therethrough. The inside diameter of the
mounting flange 22 is greater than the outside diameter of the
lower housing 18 such that an annular space is formed between the
outside wall surface of the lower housing 18 and the inside wall
surface of the mounting flange 22. A packing gland follower ring 28
is adapted to fit in the annular space formed by the housing 18 and
the mounting flange 22. Integral to the interior of the housing 18
is a wash pipe 30 which may be machined from the metal forming the
housing 18 down to a hard smooth chrome finish. The wash pipe
section begins at the shoulder 32 machined on the lower housing 18.
If desired the wash pipe 30 could be a separable member and
attached to the housing 18 by conventional thread means. The
outside diameter of the wash pipe 30 is smaller than the inside
diameter of the packing gland follower 28 such that the packing
gland 28 can be easily moved longitudinally up and down the wash
pipe 30. The housing 18 is further provided with a side outlet tube
24 mounted thereon by conventional means such as welding. On the
extreme end of the side outlet tube 24 is a side outlet flange 26.
In the operation of the drill head 10, the cuttings, debris and
fluids are exited from the well via the side outlet tube 24.
Mounted on the upper mounting flange 22 of the lower assembly 12 is
the upper assembly 14 of the drill head 10. The upper assembly 14
includes the rotating parts of the drill head 10 and may be
assembled separately prior to being mounted on the upper mounting
flange 22. The upper assembly 14 includes a bearing housing spacer
tube 34. Attached to the upper and lower ends of the bearing
housing tube 34 are flanges 36 and 38 respectively which are held
in place by a plurality of upper assembly retaining bolts 40. The
retaining bolts 40 are placed in position only after the complete
assembly of the upper assembly 14.
A rotating sleeve 42, sometimes referred to as a rotating bowl, is
mounted within the annulus formed by the interior of the bearing
housing spacer 34. The opening formed within the rotating sleeve 42
narrows at 104, which is located towards the bottom of the sleeve
42. A projection 102 is formed at the bottom edge of the sleeve 42.
Means for receiving threaded bolts are provided on both the upper
and lower edges of the sleeve 42. The lower flange 38 is provided
with a shoulder 44 on its interior surface in which rests an outer
race member 46 which acts as a track for bearings 48a. The bearings
48a are received within a seat 50 of an inner race member 52 which
engages a shoulder 54 formed on the lower exterior surface of the
sleeve 42. The bearings used in the preferred embodiment are
preferably of the roller tapered type having both thrust and radial
capabilities.
A similar configuration also occurs at the upper end of the bearing
housing spacer 34. The upper flange 36 is provided with a shoulder
56 on its interior surface in which rests an outer race member 58
which acts as a track for bearings 48b which are received within a
seat 60 of an inner race member 62 which engages a shoulder 64
formed at the upper exterior surface of the rotating sleeve 42.
Interposed between the lower flange 38 and the lower end of the
sleeve 42 are conventional grease seals and dust keepers 68a which
are held in position by conventional means in a groove 66 formed in
the lower flange 38 and the flange 22.
Similarly, interposed between the upper flange 36 and the upper end
of the sleeve 42 are conventional grease seals and dust keepers 68b
which rest in a shoulder 70 formed in the flange 36, said grease
seals 68b being conventionally held in place.
The upper assembly 14 is held together by the upper assembly
retaining bolts 40. These bolts merely serve to hold the upper
assembly 14 together should it be necessary to remove the upper
assembly 14 from the lower assembly 12.
The annular space formed by the inside wall of the bearing housing
spacer 34 and the outside wall of the sleeve 42 is filled with some
form of lubricant via conventional grease fittings or circulating
coolant and or lubricant circulated by external mechanical means.
(not shown)
The flanges 36, 38, and 22 are provided with a plurality of holes
for receiving hold down bolts 74 when the holes are in alignment,
these bolts should be fabricated from a hard tempered steel and are
utilized to hold the upper assembly 14 to the lower assembly. Great
strength is a characteristic necessary for the hold down bolts 74,
for they are utilized to transfer any thrust generated against the
rotating sleeve 42 down to the well head via the struts 20.
A resilient mass 76 having a cap 78 at one end and an elongated
taper at the other end and an opening formed through the
longitudinal axis of the mass 76 forms what is commonly referred to
as drilling rubber, this usually is a steel reinforced rubber. The
cap 78 is adapted to rest on a shoulder 80 within the opening
formed by an annular lip 82 on the upper interior wall of the
sleeve 42. A metallic collar 84 having an annular recess formed by
a shoulder 86 is designed to be placed over the drilling rubber 76
when seated on the shoulder 80 and is fixed to the rotating sleeve
42 by bolt means 88, thereby also compressively holding the
drilling rubber to the rotating sleeve 42. In operation, the drill
head 10 has a kelley, passed downwardly through the drilling rubber
76 into the well casing which is of course rigid. The drilling
rubber 76 provides a tight fit for the kelley thereby sealing the
well pressure from the atmosphere. Because of the inherent design
of the drilling rubber 76, the greater the interior well pressure,
the greater the seal becomes between the drilling rubber 76 and the
kelley.
The upper assembly 14 is mounted on the lower assembly by the
mounting bolts 74. There is thus formed an annular void between the
shoulder 102 formed on the bottom of sleeve 42 and the outside
surface at the upper extremity of the wash pipe 30. Into this void
is packed a packing material 90 such as braided Teflon. The packing
gland follower 28 is adapted to fit into the void for the
application of compression on the packing material 90 and is held
in place by adjusting bolts 92 which are threadedly fixed into the
bottom of the sleeve 42. The tighter that the bolts 92 are made,
the greater the compression, therefore the greater the seal which
exists between the sleeve 42 and the wash pipe 30. However, it is
to be noted that if too much force is applied initially to the
bolts 92, the packing 90 will wear out that much more rapidly. It
can be seen that it is no major task to repack the packing 90 since
this may be accomplished simply by dropping the packing gland
follower 28 and inserting the new packing material.
There is a gap 94 formed between the lower end of the sleeve 42 and
the upper end of the wash pipe 30. The size for the gap is
determined by the upper assembly 14 and is of a size approximating
0.004 inch, if necessary, conventional shims may be used in order
to provide a gap. There is also a machined groove 96 formed on the
bottom end of the rotating sleeve 42 which functions to direct any
well pressures down to the top of the packing means 90. The greater
the well pressure, the greater the seal which exists between the
sleeve 42 and the wash pipe 30. This occurs because the well
pressure is applied to the top of the packing 90, but since the
packing 90 is held in place by the packing gland follower 28, the
packing 90 must of necessity expand horizontally which thus results
in a tighter seal between the sleeve 42 and the wash pipe 30.
However, if a seal leak is caused to be made by intense well
pressure, such as that generated by a blowout, any debris which is
exited will be directed down through the void containing the
packing material 90, and out, leaving the grease seals 68a intact.
This very important feature will be further amplified.
In operation, the sleeve 42 is caused to be rotated by the kelley.
The packing gland follower 28 is constrained to rotate with the
sleeve by the bolts 92. This results in the packing 90 to also
rotate about the stationery wash pipe 30. This necessitates after a
period of time, because of wear and tear caused by heat and
friction; the adjusting of the packing 90, which is no major
undertaking since with the instant invention it is down simply by
raising the packing gland follower 28 by tightening the bolts 92,
thereby, applying further compression on the packing material 90.
In the event it is necessary to insert new packing material, this
is accomplished by simply lowering the packing gland follower 28
and inserting new packing material.
Reference is now made to FIGS. 2 and 3 for a better understanding
as to how the self energizing feature of the packing means
operates. FIG. 2 illustrates the groove 96 connected to a plurality
of what are referred to as pressure inlets 98. The pressure inlets
98 originate from the interior of the annulus 100, in other words,
the pressure inlets 98 are in communication with whatever exists in
the annulus 100, which in turn is in communication with the well.
Initially, because of pressure applied by the packing gland
follower 28, some of the packing 90 will flow into the gap 94 (FIG.
3). It can be seen, that upon the existence of any well pressure,
the well pressure, P1, will be directed into the pressure inlets 98
and into the groove 96 which thus provides direction means for
applying the forces generated by the internal well pressures
directly on top of the packing 90. This in turn, necessarily,
because of the increased compression results in the tightening of
the seal between the rotating sleeve 42 and the stationery wash
pipe 30. Obviously, if a blowout were to occur, it would be
necessary to stop the rotation of the kelley, since any rotation
would quickly enhance the destruction of the packing material
90.
However, if the pressure inlets 98 and the groove 96 were to be
absent, the forces generated by the well pressure, shown as dotted
arrows P2, would result in the packing 90 being compressed
sideways, thus eventually resulting in a gap being formed alongside
the wash pipe 30, as shown by the dotted lines in FIG. 3. Thus it
can be seen, that without the inlets 98 and groove 96, the seal
would be lost much more readily.
* * * * *