U.S. patent application number 13/998133 was filed with the patent office on 2014-07-17 for increased point of contact tungsten carbide insert for fixed rotary drill bit.
This patent application is currently assigned to Hi-Jet, LLC (2). The applicant listed for this patent is Hi-Jet, LLC. Invention is credited to Spencer David Hendrix, Rafe E. Neasbitt, Jonathan R. Schmidt, Zan Elden Svendsen.
Application Number | 20140196958 13/998133 |
Document ID | / |
Family ID | 51164323 |
Filed Date | 2014-07-17 |
United States Patent
Application |
20140196958 |
Kind Code |
A1 |
Schmidt; Jonathan R. ; et
al. |
July 17, 2014 |
Increased point of contact Tungsten Carbide insert for fixed rotary
drill bit
Abstract
A fixed rotary drill bit, especially the type rotary drill bits
incorporating a plurality of spaced polycrystalline diamond compact
(PDC) cutters or cutting elements on a plurality of radial blades,
includes multiple tungsten carbide inserts (TCI) spaced between the
PDC cutters or cutting elements, each TCI providing a mitigation to
vibration for the drill bits, rapidly adapting the TCIs by wear
from the intermediary formation ridges created from drilling
resulting in the creation of a unique kerf in each TCI, thus
increasing stability of the bit from lateral instability, making
the drill bit more efficient, and promoting a continual steady
state of drilling.
Inventors: |
Schmidt; Jonathan R.;
(Norman, OK) ; Neasbitt; Rafe E.; (Norman, OK)
; Hendrix; Spencer David; (Norman, OK) ; Svendsen;
Zan Elden; (Norman, OK) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hi-Jet, LLC |
Norman |
OK |
US |
|
|
Assignee: |
Hi-Jet, LLC (2)
|
Family ID: |
51164323 |
Appl. No.: |
13/998133 |
Filed: |
October 4, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61849023 |
Jan 17, 2013 |
|
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|
Current U.S.
Class: |
175/428 ;
175/426 |
Current CPC
Class: |
E21B 10/567 20130101;
E21B 10/43 20130101 |
Class at
Publication: |
175/428 ;
175/426 |
International
Class: |
E21B 10/567 20060101
E21B010/567; E21B 10/56 20060101 E21B010/56; E21B 10/55 20060101
E21B010/55 |
Claims
1. An improvement to a fixed rotary drill bit defining a singular
cast body forming a lower threaded end, lateral rounded margins,
and an upper surface defining a plurality of fixed blades, each
blade forming a plurality of spaced cutting element sockets, each
cutting element socket containing an individual cutting element,
said improvement comprising: a plurality of intermittent tungsten
carbide insert sockets cast or milled within each blade between a
rotational pathway of a plurality of paired sets of cutting
elements, each tungsten carbide insert socket containing a singular
tungsten carbide insert (TCI), each said tungsten carbide insert
located equidistant between a cutting profile of each paired
cutting element providing an enhanced and increased point of
contact tungsten carbide insert in a polycrystalline diamond
compact (PDC) fixed rotary drill bit, the improvement further
providing a secondary form of stability to mitigate vibration from
starting, stopping and steady state drilling to maintain and
stabilize the drill bit.
2. The improvement to a fixed rotary drill bit, as disclosed in
claim 1, further comprising: each said cutting element is a
polycrystalline diamond compact (PDC) cutter affixed within each
said cutting element socket by brazing and/or adhesive; each said
TCIs is attached within each respective said tungsten carbine
insert socket by brazing and/or adhesive; and each said TCI further
including a rounded top exposed above said respective blade and
between each said respective rotational pathway of each said
respective plurality of paired sets of cutting elements, said
rounded top forming a unique wear kerf conforming to a profile of
said respective advancing paired sets of cutting elements, each
said wear kerf further engaging one of a plurality of radial
formation ridges which form within a bottom of a borehole during
steady state drilling and during initial restarting of rotation of
said fixed rotary drill bit until said fixed rotary drill bit
recommences its steady state speed of drilling, further providing
greater secondary stability to mitigate vibration from starting,
stopping and steady state drilling to maintain and stabilize said
fixed rotary drill bit.
3. The improvement to a fixed rotary drill bit, as disclosed in
claim 1, further comprising: each said TCI includes a cylindrical
cross-sectional profile and each respective said tungsten carbide
insert socket is cylindrical.
4. The improvement to a fixed rotary drill bit, as disclosed in
claim 1, further comprising: each said TCI includes a
cross-sectional profile selected from a semi-rounded shape,
including an oval, oblique or egg-shape and each respective said
tungsten carbide insert socket is shaped to strictly conform to the
shape of said TCI.
5. The improvement to a fixed rotary drill bit, as disclosed in
claim 1, further comprising: each said TCI further including a
rounded top exposed above said respective blade and between each
said respective rotational pathway of each said respective
plurality of paired sets of cutting elements, said rounded top
defining a preformed wear kerf which further conforms during wear
to a profile of said respective advancing paired sets of cutting
elements, each said wear kerf further engaging one of a plurality
of radial formation ridges which form within a bottom of a borehole
during steady state drilling and during initial restarting of
rotation of said fixed rotary drill bit until said fixed rotary
drill bit recommences its steady state speed of drilling, further
providing greater secondary stability to mitigate vibration from
starting, stopping and steady state drilling to maintain and
stabilize said fixed rotary drill bit.
6. The improvement to a fixed rotary drill bit, as disclosed in
claim 1, further comprising: each of said plurality of TCIs are
located between each advancing said paired plurality of said
cutting elements, not in-line with any preceding cutting element,
each said TCI extending above said blade to a height no greater
than an exposure height of said cutting elements and having no
interfering effect on said cutting profile of each said advancing
paired cutting elements, each said cutting element traveling along
a defined individual radial cutting pathway, with a radial pathway
of each said TCI equidistant between each said individual radial
cutting pathway of said advancing cutting elements.
7. An improvement to a fixed rotary drill bit defining a singular
cast body forming a lower threaded end, lateral rounded margins,
and an upper surface defining a plurality of fixed blades, each
blade forming a plurality of spaced cutting element sockets, each
cutting element socket containing an individual cutting element,
said improvement comprising: a plurality of intermittent tungsten
carbide insert sockets cast or milled within each blade between
paired rotational pathways of advancing paired sets of cutting
elements, each said tungsten carbide insert socket containing a
singular tungsten carbide insert (TCI), each said tungsten carbide
insert further located equidistant between a cutting profile of
each of said paired cutting element; and each of said plurality of
TCIs, not in-line with any preceding cutting element, extending
above said blade at a height no greater than an exposure height of
said advancing cutting element and having no effect on a cutting
profile of said cutting elements, with said radial pathway of each
said TCI equidistant between each said individual radial cutting
pathway of said advancing cutting elements, said TCIs providing an
increased secondary form of stability to mitigate vibration from
starting, stopping and steady state drilling to maintain and
stabilize the drill bit.
8. The improvement to a fixed rotary drill bit, as disclosed in
claim 7, further comprising: each said cutting element is a
polycrystalline diamond compact (PDC) cutter affixed within each
said cutting element socket by brazing and/or adhesive; each said
TCIs is attached within each respective said tungsten carbine
insert socket by brazing and/or adhesive; and each said TCI further
including a rounded top exposed above said respective blade and
between each said respective rotational pathway of each said
respective plurality of paired sets of cutting elements, said
rounded top forming a unique wear kerf conforming to a profile of
said respective advancing paired sets of cutting elements, each
said wear kerf further engaging one of a plurality of radial
formation ridges which form within a bottom of a borehole during
steady state drilling and during initial restarting of rotation of
said fixed rotary drill bit until said fixed rotary drill bit
recommences its steady state speed of drilling, further providing
greater secondary stability to mitigate vibration from starting,
stopping and steady state drilling to maintain and stabilize said
fixed rotary drill bit.
9. The improvement to a fixed rotary drill bit, as disclosed in
claim 7, further comprising: each said TCI includes a cylindrical
cross-sectional profile and each respective said tungsten carbide
insert socket is cylindrical.
10. The improvement to a fixed rotary drill bit, as disclosed in
claim 7, further comprising: each said TCI includes a
cross-sectional profile selected from a semi-rounded shape,
including an oval, oblique or egg-shape and each respective said
tungsten carbide insert socket is shaped to strictly conform to the
shape of said TCI.
11. The improvement to a fixed rotary drill bit, as disclosed in
claim 7, further comprising: each said TCI further including a
rounded top exposed above said respective blade and between each
said respective rotational pathway of each said respective
plurality of paired sets of cutting elements, said rounded top
defining a preformed wear kerf which further conforms during wear
to a profile of said respective advancing paired sets of cutting
elements, each said wear kerf further engaging one of a plurality
of radial formation ridges which form within a bottom of a borehole
during steady state drilling and during initial restarting of
rotation of said fixed rotary drill bit until said fixed rotary
drill bit recommences its steady state speed of drilling, further
providing greater secondary stability to mitigate vibration from
starting, stopping and steady state drilling to maintain and
stabilize said fixed rotary drill bit.
12. The improvement to a fixed rotary drill bit, as disclosed in
claim 7, further comprising: each of said plurality of TCIs are
located between each advancing said paired plurality of said
cutting elements, not in-line with any preceding cutting element,
each said TCI extending above said blade to a height no greater
than an exposure height of said cutting elements and having no
effect on said cutting profile of said cutting elements, each said
cutting element travels along an individual radial cutting pathway,
with a radial pathway of each said TCI equidistant between each
said individual radial cutting pathway of said advancing cutting
elements.
13. An improvement to a fixed rotary drill bit defining a singular
cast body forming a lower threaded end, lateral rounded margins,
and an upper surface defining a plurality of fixed blades, each
blade forming a plurality of spaced cutting element sockets, each
cutting element socket containing an individual cutting element,
said improvement comprising: a plurality of intermittent tungsten
carbide insert sockets cast or milled within each blade between
paired rotational pathways of advancing paired sets of cutting
elements, each said tungsten carbide insert socket containing a
singular tungsten carbide insert (TCI), each said tungsten carbide
insert further located equidistant between a cutting profile of
each of said paired cutting element and each said TCI extending
above said blade at a height no greater than an exposure height of
said advancing cutting elements and having no effect on a cutting
profile of each said cutting element, with said radial pathway of
each said TCI equidistant between each said individual radial
cutting pathway of said advancing paired sets of cutting elements,
and each said TCI further defining a rounded top exposed above said
blade, said rounded top forming by intended and unique wear kerf
conforming to said cutting profile of said respective advancing
paired cutting elements, said improvement providing a secondary
stabilizing forces to said improved fixed rotary bit to mitigate
vibration from starting, stopping and steady state drilling to
maintain and stabilize the drill bit.
14. The improvement to a fixed rotary drill bit, as disclosed in
claim 13, further comprising: each said cutting element is a
polycrystalline diamond compact (PDC) cutter affixed within each
said cutting element socket by brazing and/or adhesive; and each
said TCIs is attached within each respective said tungsten carbide
insert socket by brazing and/or adhesive.
15. The improvement to a fixed rotary drill bit, as disclosed in
claim 13, further comprising: each said TCI includes a cylindrical
cross-sectional profile and each respective said tungsten carbide
insert socket is cylindrical.
16. The improvement to a fixed rotary drill bit, as disclosed in
claim 13, further comprising: each said TCI includes a
cross-sectional profile selected from a semi-rounded shape,
including an oval, oblique or egg-shape and each respective said
tungsten carbide insert socket is shaped to strictly conform to the
shape of said TCI.
17. The improvement to a fixed rotary drill bit, as disclosed in
claim 13, further comprising: each said TCI further including a
rounded top exposed above said respective blade and between each
said respective rotational pathway of each said respective
plurality of paired sets of cutting elements, said rounded top
defining a preformed wear kerf which further conforms during wear
to a profile of said respective advancing paired sets of cutting
elements, each said wear kerf further engaging one of a plurality
of radial formation ridges which form within a bottom of a borehole
during steady state drilling and during initial restarting of
rotation of said fixed rotary drill bit until said fixed rotary
drill bit recommences its steady state speed of drilling, further
providing greater secondary stability to mitigate vibration from
starting, stopping and steady state drilling to maintain and
stabilize said fixed rotary drill bit.
18. The improvement to a fixed rotary drill bit, as disclosed in
claim 13, further comprising: each of said plurality of TCIs are
located between each advancing said paired plurality of said
cutting elements, not in-line with any preceding cutting element,
each said TCI extending above said blade to a height no greater
than an exposure height of said cutting elements and having no
effect on a cutting profile of said cutting elements, each said
cutting element travels along an individual radial cutting pathway,
with a radial pathway of each said TCI equidistant between each
said individual radial cutting pathway of said advancing cutting
elements.
19. The improvement to a fixed rotary drill bit, as disclosed in
claim 13, further comprising: each said cutting element is a
polycrystalline diamond compact (PDC) cutter affixed within each
said cutting element socket by brazing and/or adhesive; each said
TCIs is attached within each respective said tungsten carbine
insert socket by brazing and/or adhesive; and each said TCI further
including a rounded top exposed above said respective blade and
between each said respective rotational pathway of each said
respective plurality of paired sets of cutting elements, said
rounded top forming a unique wear kerf conforming to a profile of
said respective advancing paired sets of cutting elements, each
said wear kerf further engaging one of a plurality of radial
formation ridges which form within a bottom of a borehole during
steady state drilling and during initial restarting of rotation of
said fixed rotary drill bit until said fixed rotary drill bit
recommences its steady state speed of drilling, further providing
greater secondary stability to mitigate vibration from starting,
stopping and steady state drilling to maintain and stabilize said
fixed rotary drill bit.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] Applicant claim the benefit of the U.S. Provisional Patent
Applicant No. 61/849,023, filed on Jan. 17, 2013 by two of four
inventors and to the same assignee.
I. BACKGROUND OF THE INVENTION
[0002] 1. Field of Invention
[0003] A fixed rotary drill bit, preferably a rotary drill bit
incorporating a plurality of spaced polycrystalline diamond compact
(PDC) cutters or cutting elements on a plurality of radial blades,
includes multiple tungsten carbide inserts (TCI) spaced between the
PDC cutters or cutting elements, the TCI providing a mitigation to
vibration for the drill bits, quickly adapting the TCIs by wear to
the formation ridges created from drilling by the creation of a
kerf in each TCI, thereby increasing stability of the bit from
lateral instability, making the drill bit more efficient, and
promoting a continual steady state of drilling.
[0004] 2. Description of Prior Art
[0005] A preliminary review of prior art patents was conducted by
the applicant to determine prior art patents in a similar field or
having similar use. The prior art inventions do not disclose the
same or similar elements as the present tungsten carbide insert
placed between the multiple cutters on the drill bit, nor do they
present the material components in a manner contemplated or
anticipated in the prior art when viewed alone or when viewed in
combination and assessed by those skilled in the filed of fixed
rotary drill bits.
[0006] In U.S. Pat. No. 5,588,170 to Thigpen, a tungsten carbine
button (TCB) is positioned on a lateral surface of the fixed rotary
cutter bit. It is disclosed in FIGS. 32 and 33 as #132 and FIGS. 34
and 35 as #152. Its function is discussed in Columns 9-11, with the
limitations including each TCB having the same gauge and positioned
to be at the exactly same diameter as the cutting face on the
stabilizer ribs or kickers. The use is entirely lateral and is
intended to take the impact instead of the cutter to protect the
cutter structure. The TCB may be made of tungsten carbide or any
other hard metal material or the like. It also is intended to limit
bit whirl to stabilize the drill bit within the borehole and acts
as a depth limiter for the PDC cutter assembly to keep it from
cutting too deep. In column 11, it is placed between two
neighboring cutters, but in-line with neighboring PDC cutting
elements. It is also preferably not placed in front of or behind
the neighboring PDC cutting elements with respect to the bit
rotation, which gives rise to ambiguity and also makes the patent
description very confusing and internally inconsistent. The TCB is
not the same thing as the penetration limiters (170) which are the
more important aspect of the claimed subject matter, the
penetration limiters aligned within the same rows as the cutters.
This patent is distinguishable from the present TCI especially in
light of the preferred placement of the TCI, the intended formation
of the kerf in the TCI, and the disclosed distinctive purpose.
[0007] The inclusion of U.S. Pat. Nos. 6,684,967 and 6,308,790 to
Wilmot are included to address prior and common reference
terminology for cutting profiles in drill bits, with FIG. 5
disclosing most useful terminology for cutting profiles. No mention
is made of any TCI or equivalent term but some of the terminology
may be found useful in providing definition to some of the terms
used in the present patent application.
[0008] In U.S. Pat. No. 7,594,554 to Schwefe, U.S. Pat. No.
7,762,355 to McClain, U.S. Pat. No. 8,100,202 to Durairajan, and
U.S. Pat. App. Nos. 2001/0020551 to Taylor, 2009/0145663
Durairajan, and 2012/0186879 to Durairajan, backup cutters are
aligned into cutting rows, with each subsequent cutter following in
the same intended rotational pathway. These dual rows of cutters,
or in some cases plural rows of cutters, generally provide a first
row cutters higher than second row cutters and so forth. The
Durairajan patents which are published in 2009 and 2012, both
include in their drawings something that is labeled reference
number 155, but it is not defined in the specification. This
reference item appears to be the same functional feature that is
claimed in the Thigpen patent, but it is unsupported in the claims
or specification with any specific definition or description. At
best, it appears to be a lateral surface impact bumper.
[0009] Ganz has some language within Column 6 that discusses the
inclusion of bearing elements which give the bit a bearing quality,
being located on portions of blades that are located within the
cone of the crown of the bit with an intended function to provide
sufficient surface area to withstand the axial or longitudinal
weight on bit (WOB) without exceeding the compressive strength of
the formation being drilled, so that the rock does not unduly
indent or fail and the penetration of the PDC cutters into the rock
is substantially controlled. It further is intended that the
bearing element act as a limiter of the depth of cut (DOC) of the
cutters. There is no disclosed language to indicate a preference of
intermediate placement between and behind the cutters, as within
the present TCI intermediate placed application context. Therefore,
both functional distinction and geographical location is
distinguishable from the present application subject matter.
[0010] In U.S. Pat. No. 5,090,492 to Keith, distinction is drawn
between the present TCI technology in that Keith provides
stabilizing projections immediately behind the primary cutting
element on the end face behind each set of primary cutting
elements. Each stabilizing projection is peripherally elongated in
an arcuate configuration while being of a rounded, non-cutting
configuration and dimension so as to snugly enter into the helical
groove cut by the primary cutter with a lower profile height than
the primary cutting elements, unlike the TCIs of the present drill
bit which are placed between the cutting elements with the intent
to quickly wear, forming a wear kerf which allows the TCI to ride
within the formation ridges between the cutting grooves. The TCI's
are positioned at some height above the bit body profile up to the
cutting profile of the PDC and fitting upon the formation ridges
cut into the formation by the PDC cutters.
II. SUMMARY OF THE INVENTION
[0011] The primary objective of the present TCI technology is to
keep the fixed rotary bit in a steady state of drilling and to
eliminate or minimize vibration. The TCIs deter bit instability by
continued engagement of the formed kerf with the formation ridges
created by the PDC cutters. During the drilling process, a fixed
rotary polycrystalline diamond compact (PDC) drill bit encounters a
variety of forces. A secondary objective is met when the rotation
of the drill bit is ceased and recommenced, wherein vibration
occurs upon a recommencement of the drilling until the bit returns
to a steady state of drilling. These vibration occur from the drill
bit attempting to re-engage the formation ridges which are created
by the drill bit from prior drilling operations prior to the drill
bit being stopped. These start-up vibrations and forces can cause a
great amount of damage to PDC cutters and chip or undesirably erode
causing the rotary bit to become prematurely dull and eventually
useless, requiring replacement. This vibration from start-up
rotational forces can be mitigated by the placement of additional
items within the drill bits to reduce and mitigate the vibration.
Historically, as disclosed above, these additional items have been
in the form of tungsten carbide buttons, stabilizing projections
and bearing elements which are placed on the drill bit at location
behind the cutters in line with the radial cutter positions. While
providing their intended function, they do not and cannot provide
the same benefit to the drill bit as the tungsten carbide inserts
(TCI) disclosed in the present intermediately placed tungsten
carbide insert providing an increased point of contact with the
formation ridges within the hole, mitigating damaging vibrational
forces upon recommencement of drilling into the formation and in
the steady state of drilling.
[0012] It is the objective of the present TCI to be strategically
placed within the fixed rotary bit as a mechanical feature which is
not necessarily intended to provide force balancing or a primary
form of stability, but to mitigate vibration presented at start-up,
stopping, and steady state drilling into a formation by increasing
points of contact with the formation ridges created from drilling
within the bore hole. This is accomplished by placing the TCIs
between the profiles of the PDC cutters with the TCIs being
intentionally quickly worn over use to form a wear kerf which
adjusts to the intermediary cutting profiles of the advancing PDC
cutters along the same radial cutting positions as the proceeding
PDC cutters. Because of design constraints, the type of TCI used
and the TCI placement on each rotary bit blade, the wear kerf may
not be centered on each TCI and will vary in depth, size, surface
location and axis. These wear kerfs may also vary in proportion to
the rate of penetration (ROP) and the exposure of the PDC cutters
behind which each TCI is placed, with the wear kerfs on the TCIs
behind and between the low ROP cutters being more shallow and less
noticeable and those wear kerfs on the TCIs behind and between the
higher ROP cutters being deeper and more noticeable.
III. DESCRIPTION OF THE DRAWINGS
[0013] The following drawings are submitted with this utility
patent application.
[0014] FIG. 1 is a top end view of a prior art fixed rotary drill
bit with a plurality of cutting elements installed upon each of a
plurality of blades.
[0015] FIG. 2 is a perspective top view of a prior art fixed rotary
drill bit with some of the plurality of cutting elements installed
upon each of a plurality of blades indicating lateral and bottom
end geographical features of such prior art fixed rotary blade.
[0016] FIG. 3 is a top end view of a fixed rotary drill bit with a
plurality of cutting elements installed upon each of a plurality of
blades with the addition of a plurality of intermediately placed
tungsten carbide inserts further installed behind and between pairs
of selected cutting elements.
[0017] FIG. 4 is a side perspective and profile isolated view of a
singular blade of the fixed rotary drill bit including the
plurality of tungsten carbide insets behind and between selected
pairs of cutting elements.
[0018] FIG. 5 is a cross-sectional side view of a singular blade of
the fixed rotary drill bit including some of the tungsten carbide
inserts seated within the blade, with phantom lines showing the
cutting profile of the fixed rotary drill bit and the plurality of
cutting elements along each blade indicating a center of each
cutting element cutting face.
[0019] FIG. 6 is a cross-sectional side view of a singular blade of
the fixed rotary drill bit including some of the tungsten carbide
inserts seated within the blade, with phantom lines showing the
cutting profile of the fixed rotary drill bit and the plurality of
cutting elements along each blade indicating a center of each
cutting element cutting face and exemplary intentional wear kerfs
formed in each tungsten carbide insert after being worn by use.
[0020] FIG. 7 is a cross-sectional side view of a singular blade of
the fixed rotary drill bit including some of the tungsten carbide
inserts seated within the blade, with phantom lines showing the
cutting profile of the fixed rotary drill bit and the plurality of
cutting elements along each blade indicating a center of each
cutting element cutting face and exemplary intentional wear kerfs
formed in each tungsten carbide insert after being worn by use in
relationship with the bore hole formed by the fixed rotary drill
bit, with the ridge formations within the bore hole formed between
the cutting elements and as contained within wear kerfs trailing
the cutting elements during rotation.
[0021] FIG. 8 is a reference drawing indicating a top end view of a
fixed rotary drill bit having a first cutting element, a second
cutting element and a singular tungsten carbide insert for the sole
purpose of representing a rotational pathway of the first cutting
element, the second cutting element and the singular tungsten
carbide insert.
IV. DESCRIPTION OF THE PREFERRED EMBODIMENT
[0022] Fixed rotary drill bits are known in the oil and gas
drilling industry. These fixed rotary drill bits 10, as shown in
FIGS. 1 and 2 of the drawings, generally comprise a singular cast
body 20 which forms a lower threaded end 22, lateral rounded
margins 24, and an upper surface 26 defining a plurality of fixed
blades 30, each blade forming a plurality of spaced cutting element
sockets 40, each cutting element socket containing an individual
cutting element 45. The prior art cutting elements 45 are often a
polycrystalline diamond compact (PDC). Various patents have been
devoted to the composition and manufacture of the PDC cutting
elements, their orientation, the angle of placement and the
thickness and physical property of the PDC cutting elements. For
purpose of the present improvement, these PDC features are
irrelevant, other than the fact that the present improvement
contains these prior art technologies. These prior art patents also
provide the present improvement with certain geographical
terminology that is incorporated into the present improvement to
assist those skilled in the art with reference for the present
improvement. In the prior art, the PDC cutting elements are secured
within each socket by brazing, with an adhesive, or by other means,
which secure the cutting elements 45 within the sockets 40 in a
manner which enables the cutting elements 45 to remain within the
sockets 40 under high pressure, high temperature and under high
impact forces during the drilling process. This secure installation
is also the subject matter of several prior art patents that are
not relevant to the present improvement, with the exception of a
similar manner of attachment being used to mount the improvement
within the fixed rotary drill bit 10 as used to secure the PDC
cutting elements 45 within the cutting element sockets 40 on the
blades 30 formed on the upper surface 26 of the singular cast body
20.
[0023] The present improvement provides the fixed rotary drill bit
10 with an enhanced and increased point of contact tungsten carbide
insert in a polycrystalline diamond compact (PDC) fixed rotary
drill bit, the improvement further providing a secondary form of
stability to mitigate vibration from starting, stopping and steady
state drilling to maintain and stabilize the drill bit.
[0024] The present improvement comprises the addition of a
plurality of intermittent and strategically placed tungsten carbide
insert sockets (TCI sockets) 100 cast or milled within each blade
30 of a fixed rotary drill bit 10 between a rotation pathway of a
plurality of selected paired set of PDC cutting elements 45a, 45b,
each TCI socket 100 inserting and securing a tungsten carbide
insert (TCI) 105 within the fixed rotary PDC drill bit 10. The TCI
105 placement increases the points of contact by each TCI 105
forming a unique wear kerf 106 coinciding with the profile of the
advancing paired PDC cutting elements 45a, 45b. These wear kerfs
106 will further engage the formation ridges C which form within
the bottom B of the borehole A during drilling and during the
initial restarting of the rotation of the drill bit 10 until the
drill bit 10 recommences its steady state speed of drilling. It
should be noted that while the preferred embodiment of the insert
would be a TCI 105, the insert may be composed of any material
which would be a plausible substitute or a substantial equivalent
of tungsten carbide with regard to the physical characteristics and
intended use of the tungsten carbide insert as described herein.
Therefore, TCI 105 or its substantial equivalent, will be
referenced as TCI 105, regardless of its actual composition. Each
TCI 105 is secured within a respective TCI socket 100 using the
same bonding as is used to secure the PDC cutting elements 45
within each PDC cutting element socket 40 by brazing, with an
adhesive, or by other means, which secure the cutting elements 45
within the sockets 40 in a manner which enables the cutting
elements 45 to remain within the sockets 40 under high pressure,
high temperature and under high impact forces during the drilling
process.
[0025] The placement of the TCI 105 and each respective TCI socket
100 is crucial to the improvement. Unlike prior mechanical features
which are provided merely to stabilize a rotary drill bit 10,
including tungsten carbide buttons, stabilizing projections and
bearing elements which are placed on the drill bit at location
behind the cutters in line with the radial cutter positions with
little or no wear over the life of the drill bit, the TCIs 105 are
preferably cylindrical and are inserted and incorporated into the
blade 30 of the fixed rotary bit 10 in an erect or vertical
position, are made of the indicated tungsten carbide material which
is more soft than the PDC cutting elements 45 and the drill bit 10
with the intention to become worn. It is also preferred that the
shape of each TCI 105 is cylindrical with a rounded top 108, giving
each TCI 105 the shape resembling a bullet as its original shape at
the time the fixed rotary drill bit 10 is manufactured and
presented for sale and use, with the cylindrical portion bonded
within the ICI socket 100 exposing the rounded top 108 above the
margin of the respective blade 30 within which each ICI 105 is
located. It is also contemplated that each wear kerf 106 may also
be derived from a pre-formed indentation within the upper rounded
top 108 which will subsequently wear into a unique wear kerf behind
each respective paired PDC cutting elements 45a, 45b. It is also
contemplated that each TCI may assume a shape other than
cylindrical, including a vertical profile having an oval, oblique
or egg-shape configuration with each respective non-cylindrical
shaped TCI 105 having a TCI socket 100 cast or milled to accept
each non-cylindrical TCI 105.
[0026] The TCIs 105 are located between the proceeding paired PDC
cutting elements 45a, 45b, not in-line with any preceding PDC
cutting element 45, and extend from slightly above the blade 30 all
the way up to the exposure of the cutting elements 45, having no
effect on the cutting profile of any advancing paired PDC cutting
element 45a, 45b, FIGS. 3-8. As seen in FIG. 8, each PDC cutting
element 45a, 45b, travels along an individual radial cutting
pathway, indicated by R1 And R3 for one selected pair of PDC
cutting elements 45a, 45b. The radial pathway of the TCI 105 is
optimally half way between R1 and R3, indicated by R2. While
optimally half way between the radial cutting pathway, it is
recognized that placement of each of the plurality of TCIs 105
located on the fixed rotary bit 10 will vary to some degree due to
spacial limitations and structural concern, but each TCI 105 should
be as close to half way between the advancing paired PDC cutting
elements 45a, 45b, as possible. This placement of each TCI 105 will
also affect the size, shape and depth of each respective wear kerf
106 on each TCI 105, with those place precisely half way between
each paired PDC cutting elements 45a, 45b, being relatively
centered and those slightly offset being located somewhat off
center.
[0027] Once the operational depth of each respective wear kerf 106
is set and the TCI 105 has adjusted to fit completely within the
profile of the advancing PDC cutting elements 45a, 45b, the TCI 105
will conform to the formation ridges C in the same manner as the
PDC cutting elements 45a, 45b, and will reduce some of the forces
on the PDC cutting elements 45a, 45b, as the drill bit accelerates
from a complete stop to the steady state of shearing and further
cutting into the earth at the bottom of the borehole. The concept
improvement would strategically place the TCI's 105 between each
paired PDC cutting elements 45a, 45b, on the same blades 30 in a
position to ride the formation ridges C created while drilling,
quickly creating the wear kerf 106 in the TCI's 105 and rapidly
assisting in the stabilization of the bit from lateral instability
and make the drill bit drill more efficiently and promote an
improved continual steady state of drilling.
[0028] While a plurality of TCI's 105 is essential to the
improvement to the fixed rotary PDC drill bit 10, it is also
contemplated that the TCI's 105 may include partially pre-cut wear
kerfs, elongated TCIs 105 which are non-cylindrical and also
multiple TCI's 105 located upon the same radial pathway. It is not
intended that the TCI 105 affect the cutting pathway of the
advancing paired PDC cutting elements 45a, 45b, unlike prior art
patents which provide the mechanical features above the height of
the advancing cutters to limit cutting depth, even though there may
be a small amount of effect on the borehole during the initial use
of the TCI containing drill bit until the respective wear kerfs are
established. The wear kerfs 106 will also be affected differently,
as previously mentioned by their inability to be placed exactly the
same along the blades 30 of the fixed rotary bit 10 and also as
they extend along the lateral surfaces of each blade, resulting in
different positions, shapes and depths of the respective wear kerfs
106. Ideally, and as shown in FIG. 8, the TCI 105 position would
provide R2 half way between R1 and R3 in a simple mathematical
formula having R2=(R1+R3)/2, but this is ideal and not entirely
practically anticipated. Once again, however, location of the TCIs
105 should be as close as practical.
[0029] While the invention has been particularly shown and
described with reference to a preferred embodiment thereof, it will
be understood by those skilled in the art that changes in form and
detail may be made therein without departing from the spirit and
scope of the invention.
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