U.S. patent application number 14/218630 was filed with the patent office on 2015-09-24 for drill bit having regenerative nanofilms.
This patent application is currently assigned to Halliburton Energy Services, Inc.. The applicant listed for this patent is Halliburton Energy Services, Inc.. Invention is credited to Jay Stuart Bird, Garrett T. Olsen, Ping C. Sui.
Application Number | 20150267472 14/218630 |
Document ID | / |
Family ID | 54141601 |
Filed Date | 2015-09-24 |
United States Patent
Application |
20150267472 |
Kind Code |
A1 |
Olsen; Garrett T. ; et
al. |
September 24, 2015 |
DRILL BIT HAVING REGENERATIVE NANOFILMS
Abstract
A system of repairing and protecting a surface of a drill bit
includes forming a drill bit body that includes a magnetized
material or is otherwise magnetizable. The drill bit includes at
least one cutting element and is operable to generate a magnetic
field. A drilling fluid that includes magnetizable, regenerative
particles is circulated through a drill string and wellbore in
which the drill bit is deployed. The magnetic field attracts the
regenerative particles to the surface of the drill bit body to
occupy cracks and chips formed in the surface of the drill bit
body, and to form a protective layer of the regenerative particles
over the surface of the drill bit body.
Inventors: |
Olsen; Garrett T.; (The
Woodlands, TX) ; Bird; Jay Stuart; (The Woodlands,
TX) ; Sui; Ping C.; (The Woodlands, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Halliburton Energy Services, Inc. |
Houston |
TX |
US |
|
|
Assignee: |
Halliburton Energy Services,
Inc.
Houston
TX
|
Family ID: |
54141601 |
Appl. No.: |
14/218630 |
Filed: |
March 18, 2014 |
Current U.S.
Class: |
175/65 ;
175/328 |
Current CPC
Class: |
E21B 10/46 20130101;
B82Y 30/00 20130101; C22C 2202/02 20130101; B22F 2005/001 20130101;
E21B 10/006 20130101; B22F 7/062 20130101; B22F 2007/068 20130101;
C22C 29/08 20130101 |
International
Class: |
E21B 7/00 20060101
E21B007/00; E21B 12/04 20060101 E21B012/04; E21B 10/22 20060101
E21B010/22 |
Claims
1. A wellbore formation system comprising: a drill bit having at
least one cutting element and a drill bit body comprising a
magnetized material that generates a magnetic field extending to an
exterior of the drill bit body; a drilling fluid comprising
magnetizable regenerative particles; and a fluid flow path that
guides the drilling fluid through a drill string and over a surface
of the drill bit.
2. The system of claim 1 wherein, the regenerative particles
comprise superparamagnetic nanoparticles.
3. The system of claim 2, wherein the superparamagnetic
nanoparticles comprise iron oxide.
4. The system of claim 1, wherein the drill bit body is a matrix
drill bit body, and wherein the matrix drill bit body comprises: a
particulate phase and a binder material, the particulate phase
comprising magnetic particles.
5. The system of claim 1, further comprising: an electromagnet,
wherein the drill bit body is a matrix drill bit body comprising a
particulate phase and a binder material, the particulate phase
comprising ferromagnetic particles; and wherein the drill bit body
is magnetically coupled to the electromagnet.
6. The system of claim 1, wherein the drill bit body is a matrix
drill bit body, and wherein the matrix drill bit body comprises: a
particulate phase and a binder material, the particulate phase
comprising particles of rare earth magnet.
7. The system of claim 6, wherein the rare earth magnet is selected
from the group consisting of AlNiCo, a neodymium magnet, and a
samarium-cobalt magnet.
8. The system of claim 1 wherein the drilling fluid is a
water-based drilling fluid, and wherein the regenerative materials
are functionalized for dissolution in water.
9. The system of claim 1 wherein the drilling fluid is an oil-based
drilling fluid, and wherein the regenerative materials are
functionalized for dissolution in oil.
10. A method of preserving a drill bit surface, the method
comprising: providing a drill bit having a magnetized drill bit
body that generates a magnetic field extending to an exterior of
the drill bit body; operating the drill bit to form a wellbore; and
circulating a fluid over a surface of the drill bit body to
regenerate a surface of the drill bit body, the fluid comprising
regenerative materials that are magnetically attracted to the
magnetized drill bit body.
11. The method of claim 10, wherein the regenerative materials
comprise iron oxide nanoparticles.
12. The method of claim 10, wherein the regenerative materials
comprise superparamagnetic particles.
13. The method of claim 10, wherein the drill bit comprises a
matrix drill bit body having a particulate phase component, a
binder material, the particulate phase including tungsten carbide,
and the magnetic particles.
14. The method of claim 13, further comprising activating an
electromagnet, wherein the magnetic particles comprise a
ferromagnetic material that becomes magnetized in response to
activation of the electromagnet.
15. The method of claim 10, wherein the magnetic particles comprise
particles of rare earth magnet selected from the group consisting
of AlNiCo, neodymium magnet, and samarium-cobalt magnet.
16. The method of claim 10, further comprising forming a protective
film of the regenerative materials at a surface of the drill bit
body by magnetically attracting the regenerative materials to the
surface of the drill bit body.
17. A method of manufacturing a drill bit body comprising: placing
a particulate phase and a binder material into a mold, the
particulate phase including tungsten carbide and magnetizable
particles; and sintering the particulate phase and the binder to
form a drill bit body.
18. The method of claim 17, further comprising cooling the drill
bit body following the step of sintering the particulate phase and
the binder to form the drill bit body; and, while cooling the drill
bit body, applying a magnetic field to the drill bit body.
19. The method of claim 18, wherein applying the magnetic field to
the drill bit body comprises applying a magnetic field to the drill
bit body when the magnetizable particles are at the Curie
temperature.
20. The method of claim 17, wherein the magnetizable particles
comprise particles of rare earth magnet selected from the group
consisting of AlNiCo magnet, a neodymium, and samarium-cobalt.
Description
1. TECHNICAL FIELD
[0001] The present disclosure relates to drill bits, drill bit
materials, and related methods of use.
2. DESCRIPTION OF RELATED ART
[0002] Wells are drilled to access and produce oil, gas, minerals,
and other naturally-occurring deposits from subterranean geological
formations. The drilling of a well typically is accomplished with a
drill bit that is rotated to advance the wellbore by removing
topsoil, sand, clay, limestone, calcites, dolomites, or other
materials from a formation. Pieces of such materials removed from
the formation by the drill bit are generally referred to as
"cuttings" or "drill cuttings."
[0003] A drill bit is typically classified as either a fixed cutter
drill bit or a rotary cone drill bit, which may also be referred to
as a roller cone drill bit. Generally, a rotary cone drill bit
includes a drill bit assembly having multiple rotating cones (i.e.,
"roller cones") with cutting elements. The roller cones rotate
relative to the drill bit assembly as the drill bit is rotated
downhole. In contrast, a fixed cutter drill bit includes a drill
bit body having cutting elements at fixed locations on the exterior
of the drill bit body. The cutting elements remain at their fixed
locations relative to the bit body as the drill bit is rotated
downhole.
[0004] During drilling, the drill bit experiences some of the most
intense strains and pressures of any component in the drill string.
Some of the focus in bit design is to strengthen and increase the
durability of drill bits. In some cases, material selection drives
the durability of the drill bit, and steel bits and tungsten
carbide bits have become popular because of their durability.
[0005] Fixed cutter and roller cone bit bodies are often formed of
matrix materials, and each may be referred to, accordingly, as a
matrix bit body. The materials used to form a matrix bit body may
include a powder, which is typically a hard and durable material,
and a binder material that holds the powder together to form the
bit. Since the resulting matrix in many cases does not chemically
bond the powder component and the binder together, the matrix drill
bit may be susceptible to fracturing or other types of damage if it
experiences sufficient chipping or other types of wear.
[0006] During drilling operations, the drill bit itself is perhaps
under more stress than any other part of a drill string. In
addition, damage to the drill bit may cause damage to other parts
of the drill string, including the collar that couples the drill
bit to the drill string and corresponding drive system. Small chips
and cracks resulting from wear on the drill bit are a common source
of such damage. The small chips in the structure of the drill bit
may lead to bigger gaps forming, which may eventually lead to the
complete destruction of the drill bit.
[0007] When the cost of down time for the well and drill string is
considered, the cost of repairing a drill bit having minor damage
may be significant.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Illustrative embodiments of the present disclosure are
described in detail below with reference to the attached drawing
figures, which are incorporated by reference herein and
wherein:
[0009] FIG. 1 illustrates a perspective view of one embodiment of a
roller cone drill bit;
[0010] FIG. 2 illustrates an elevation view of the roller cone bit
of FIG. 1 deployed in a drilling environment;
[0011] FIG. 3 illustrates a cross-section of one embodiment of a
roller cone and spindle of a drill bit, as indicated by the section
line A-A' of FIG. 1, wherein the roller cone includes magnetic
material and surrounding nanoparticles;
[0012] FIG. 4 illustrates a cross-section view of the roller cone
of FIG. 3 in which the roller cone is regenerating a portion of its
surface;
[0013] FIG. 5 illustrates a cross-section of a portion of a fixed
cutter drill bit that includes magnetic material and surrounding
nanoparticles;
[0014] FIG. 6 illustrates a cross-section view of the portion of
the fixed cutter drill bit of FIG. 5 in which a portion of the
surface of the drill bit is regenerating;
[0015] FIG. 7 is a schematic, cross-section view of a portion of a
drill string that includes a drill bit that is magnetically coupled
to an electromagnet; and
[0016] FIG. 8 is a block diagram of a drilling system that includes
a drill bit that is magnetically coupled to an electromagnet.
[0017] The illustrated figures are only exemplary and are not
intended to assert or imply any limitation with regard to the
environment, architecture, design, or process in which different
embodiments may be implemented.
DETAILED DESCRIPTION
[0018] In the following detailed description of the illustrative
embodiments, reference is made to the accompanying drawings that
form a part hereof. These embodiments are described in sufficient
detail to enable those skilled in the art to practice the disclosed
systems, devices, and methods. It is understood that other
embodiments may be utilized and that logical structural,
mechanical, electrical, and chemical changes may be made without
departing from the spirit or scope of the disclosure. To avoid
detail not necessary to enable those skilled in the art to practice
the embodiments described herein, the description may omit certain
information known to those skilled in the art. The following
detailed description, therefore, is not to be taken in a limiting
sense; and the scope of the illustrative embodiments is defined
only by the appended claims.
[0019] The embodiments described herein relate to drill bits that
use magnetic forces to attract and magnetically join regenerative
nanoparticles to improve the strength and durability of a drill bit
by regenerating damaged surfaces of the drill bit's body and
growing a protective nanofilm that protects the surface of the
drill bit body. Regenerating materials, such as superparamagnetic
iron oxide nanoparticles, are introduced into the drilling fluid
and are magnetically attracted by magnetic particles in the bit
body. The magnetic attraction between the regenerating materials
and magnetic particles results in the regenerating materials being
attracted to and attaching to surface of the drill bit body to fill
small chips and other surface damage to the drill bit body, and may
thereby "regenerate" the surface of the drill bit body. While the
iron oxide particles described herein are generally contemplated as
being superparamagnetic and sized on the nanoscale, it is noted
that such particles may, in other embodiments, be paramagnetic and
be sized on the microscale.
[0020] According to an illustrative embodiment, a wellbore
formation system includes a drill bit having at least one cutting
element and a drill bit body comprising a magnetized material that
generates a magnetic field extending to and beyond an exterior
surface of the drill bit body. The system further includes a
drilling fluid that is populated with magnetizable, regenerative
particles and a fluid flow path that guides the drilling fluid
through a drill string and over a surface of the drill bit. The
regenerative particles may be superparamagnetic nanoparticles, such
as iron oxide. The drill bit body may be a matrix drill bit body
that is formed from a particulate phase and a binder material. The
particulate phase includes magnetic particles, such as
ferromagnetic particles or particles of a rare earth magnet. In an
embodiment in which the magnetic particles are ferromagnetic
particles, the drill bit may include or be coupled to electromagnet
that magnetizes the ferromagnetic particles. In another embodiment,
the magnetic particles are particles of rare earth magnet, such as
AlNiCo, neodymium, and samarium-cobalt, as described in more detail
below. The drilling fluid may be a water-based drilling fluid or an
oil-based drilling fluid. In an embodiment in which the drilling
fluid is a water-based drilling fluid, the regenerative particles
are functionalized for dissolution or suspension in water. In an
embodiment in which the drilling fluid is an oil-based drilling
fluid, the regenerative particles are functionalized for
dissolution or suspension in oil.
[0021] Unless otherwise specified, any use of any form of the terms
"connect," "engage," "couple," "attach," or any other term
describing an interaction between elements is not meant to limit
the interaction to direct interaction between the elements and may
also include indirect interaction between the elements described.
In the following discussion and in the claims, the terms
"including" and "comprising" are used in an open-ended fashion and,
thus, should be interpreted to mean "including, but not limited
to." Unless otherwise indicated, as used throughout this document,
"or" does not require mutual exclusivity.
[0022] In an illustrative embodiment, the regenerative particles
are nanoparticles having superparamagnetic properties. As
referenced herein, superparamagneticism is a type of magnetism
exhibited by ferromagnetic or ferrimagnetic particles composed of a
single magnetic domain that become magnetized in the presence of a
magnetic field. Such particles may be nanoparticles having
dimensions of, for example, between 3 nanometers and 50 nanometers
(nm), or any other suitable size. The nanoparticles may be iron
oxide or other suitable types of materials. The two main forms of
iron oxide are magnetite (Fe3O4) and its oxidized form maghemite
(.gamma.-Fe2O3). Iron oxide nanoparticles in the size range of 1 nm
to 100 nm may exhibit superparamagneticism. When such nanoparticles
are magnetized, the magnetization is considered a single magnetic
moment that is the sum of all of the individual magnetic moments
carried by the atoms of the nanoparticle. The nanoparticles are
small, and may easily migrate through a drill string to a drill bit
when deployed into a drilling fluid.
[0023] In some embodiments, the regenerative material is
functionalized or processed to effectively dissolve or form a
suspension in the drilling fluid. For example, a regenerative
material such as superparamagnetic iron oxide may be functionalized
with a polar or ionic compound to make it easily dissolvable in
water or other polar solvents that serve as drilling fluid. In
embodiments in which the drilling fluid is oil based, the
regenerative materials may be functionalized or processed with
non-polar molecules to facilitate dissolution or suspension in
oil.
[0024] In an embodiment, the regenerating drill bit is a matrix
drill bit that includes a magnetic material. In general, a matrix
drill bit body is understood to be a drill bit body formed by
placing a rigid powder or particulate phase material, typically in
powder form, in a mold with a binder material, and heating the
materials to cause the binder particles to grow together and bind
the particulate phase material in the structure of the drill bit
body. A typical particulate phase material for use on a drill bit
body is tungsten carbide, and typical binder materials include
copper and cobalt. The magnetic material included in the matrix
drill bit may be in the form of particles of rare earth magnets
that are added to the powder component or particulate phase of the
matrix drill bit body. Alternatively, magnetic particles may be
formed as the matrix drill bit is constructed by heating the matrix
drill bit to the Curie temperature for the material used while
applying a magnetic field. Other types of drill bits may also be
used in which magnetic particles are incorporated in the drill bit
body.
[0025] Referring now to the figures, FIG. 1 shows a perspective
view of a roller cone drill bit, which is a common type of drill
bit used in wellbore drilling. The roller cone drill bit 100,
however, is merely an example of a commonly used type of drill bit,
and the techniques described herein may be used in a variety of
drill bits. Other suitable types of drill bits include fixed cutter
drill bits, which are further described below. In an embodiment of
a roller cone drill bit 100, rotating cones 102 have teeth 104 on
their outer surface that function as cutting elements, and each
rotating cone 102 is mounted on an arm 106 of the drill bit 100.
The roller cone drill bit 100 may include a magnetic material
embedded within the bit bodies of the roller cones 102.
[0026] FIG. 2 shows an elevation view, in partial cross-section, of
a drilling rig that includes the roller cone drill bit 100 of FIG.
1. As illustrated in FIG. 2, a drill rig 208 uses sections of pipe
210 to transfer rotational force to a drill bit 200. A pump 212 is
coupled to the pipe 210 and a drilling fluid source to circulate
drilling fluid 214 (illustrated as flow arrows A) to the bottom of
the wellbore through the sections of pipe 210 and through the drill
bit 200 during drilling. As the drill bit 200 rotates, the applied
weight-on bit ("WOB") forces the downward pointing teeth of the
rotating cones into the formation being drilled. The points of the
teeth apply a compressive stress that exceeds the yield stress of
the formation and induces fracturing in the formation. This
fracturing produces cuttings that are removed from the formation to
form the wellbore. The cuttings, however, may contact and induce
frictional forces on the body of the drill bit, and may thereby
cause damage to the bit body in the form of chipping, cracking, and
other types of wear. In an embodiment, the drilling fluid 214
contains regenerative nanoparticles and the drill bit 200 includes
magnetic particles. As described in more detail below, the magnetic
particles attract the regenerative nanoparticles to the surface of
the drill bit to regenerate damaged surfaces of the drill bit 200
and mitigate the effects of chipping, galling, cracking, and other
wear.
[0027] FIG. 3 illustrates a cross-section of one embodiment of a
roller cone of the roller cone drill bit of FIG. 1, as indicated by
the section line A-A' of FIG. 1. The roller cone drill bit 300
includes a roller cone 304 and a support arm 308. The roller cone
304 is supported on bearings 334 and a spindle 336. The roller cone
304, which may also be referred to as a bit body or a roller cone
bit body, includes magnetic material 345 and surrounding
regenerative material 350 that includes nanoparticles. In an
embodiment, the roller cone 304 may be composed of a primarily
tungsten carbide particulate phase, a binder (cobalt), and magnetic
particles 345, which may be included with the particulate phase. In
another embodiment, the roller cone 304 may be composed of casted
steel and embedded magnetic particles 345.
[0028] According to an illustrative embodiment, in operation, the
drilling fluid surrounding the roller cone bit includes
regenerative materials 350. The particles of regenerative material
350 may be nanoparticles. More particularly, in many, the
regenerative materials 350 may be superparamagnetic iron oxide
nanoparticles. For illustrative purposes, the roller cone 304
includes a chip 360 and a crack 365, which serve as examples of
damage to the roller cone 304 that may occur during drilling
operations. The chip 360 and crack 365 expose areas of the roller
cone 304 that include rough, damaged surfaces that may be subject
to additional frictional wear, or galling, as cuttings from the
wellbore are circulated over the surface of the roller cone 304. To
regenerate damaged areas and protect the surface of the roller cone
304 during drilling operations, regenerative materials 350
suspended in drilling fluid may be constantly drawn to the magnetic
materials 345 of the roller cone 304 to fill voids and form a
protective film over the surface of the roller cone 304.
[0029] The regenerative materials 350 may not, however, permanently
stick to the outer surface of the roller cone 304. In an
embodiment, the regenerative materials 350 are scraped away from
the surface of the roller cone 304 by shear forces of fluid and
cuttings that flow over the surface of the roller cone 304 during
drilling. Nonetheless, in an embodiment, constant magnetic
attraction of the regenerative materials 350 to magnetic materials
345 may increase the longevity of the roller cone 304 by forming a
transient, protective film of attracted regenerative material 350
at the surface of the bit body. Longevity of the bit body may also
be increased by filling cracks and other voids in the bit body with
regenerative materials 350. In the case of chip 360 or crack 365,
for example, regenerative material 350 fills the chip 360 and crack
345, and bonding may occur at roughened, damaged surfaces resulting
from, for example, the non-smooth crack 365 or chip 360. The
magnetic bonding of the magnetic materials 340 to the regenerative
materials 350 causes nanoparticles in the regenerative materials
350 to fill the chip 360 and crack 365, enabling the surface of the
bit body to better resist frictional forces and wearing away for a
longer period of time. Filling of cracks 365 and chips 360 with
regenerative materials 350 may also insulate the roller cone 304
from further damage by forming a protective nanofilm of the
nanoparticles at the surface of the drill bit 300 that prevents
damaging particles from entering the damaged areas.
[0030] FIG. 4 illustrates a cross-section of the roller cone 304 of
FIG. 3, showing the migration of regenerative materials 350 from a
circulating drilling fluid into the chip 360 and crack 365. Here,
the magnetic particles 345 attract regenerative materials 350, and
regenerative materials 350A fill into chip 360 and crack 365 to
regenerate and repair the drill bit. This process may occur
repeatedly during the drilling process to form a regenerative drill
bit. Recalling that the regenerative materials 350 may be
magnetized nanoparticles, it is noted that chip 360 and crack 365
are not illustrated to scale, and in operation will likely be much
smaller, having dimensions that are more appropriately measured on
the microscale (in micrometers) or nanoscale (in nanometers).
[0031] In an embodiment, the roller cone 304 is formed according to
known sintering techniques. A particulate phase including a powder
such as tungsten carbide and rare earth magnets that form the
magnetic material 340 may be mixed with binder material to form the
body of the drill bit 300. This mixture is placed in a mold for
sintering and heated to form the drill bit body. Possible rare
earth magnets that may be used in the drill bit body 304 include,
but are not limited to, AlNiCo, NdFeB, and SmCo. As referenced
herein, "AlNiCo" refers to iron alloys having a composition of
8-12% aluminum, 15-26% nickel, 5-24% Cobalt, up to 6% copper, up to
1% titanium, and iron; "NdFeB" refers to a neodymium magnet having
a composition Nd2Fe14B in a tetragonal crystalline structure; and
"SmCo" refers to samarium-cobalt magnets having a typical
composition of SmCo5. It is important to consider the temperature
ranges these rare earth magnets can sustain since the drill bit is
heated during the sintering process and during the drilling
process. The working temperature ranges for the aforementioned
materials are: from 350.degree. C. to 550.degree. C. for AlNiCo;
below 200.degree. C. for NdFeB; and from 250.degree. C. to
350.degree. C. for SmCo. The maximum temperature that the bit needs
to reach during fabrication and the maximum likely temperature of
the bit during drilling, therefore, may be considered in selecting
the appropriate rare earth magnet to use in a particular drill bit
body. In a formation that is expected to be at 350.degree. C., for
example, AlNiCo may be the appropriate rare earth magnet for use in
the bit body.
[0032] Referring now to FIG. 5a cross-sectional diagram of a
portion of a fixed cutter drill bit 500 is shown. The drill bit
body 504 of the drill bit 500 is a matrix drill bit body that
includes magnetic particles 545. The fixed cutter drill bit 500 may
be composed of, for example, a particulate phase of tungsten
carbide and magnetic particles 545, and a binder material, like the
roller cone drill bit body described previously.
[0033] In an embodiment, drilling fluid surrounding the fixed
cutter drill bit 500 includes regenerative materials 550 including
nanoparticles and, alternatively, other regenerative materials. The
regenerative materials 550 may be superparamagnetic iron oxide
nanoparticles. As shown, regenerative nanoparticles 550 are
responsive to and attracted to magnetic particles 545 embedded in
the fixed cutter drill bit body 504. During drilling operations,
chip 560 or crack 565 may occur in the fixed cutter drill bit body
504. The chip 560 or crack 565 exposes an area that includes a
rough surface at the location of the crack 565 or chip 560. During
drilling operations, regenerative materials 550 may be constantly
drawn to the surface of the fixed cutter drill bit 500 by drilling
fluid circulated in the drill string and wellbore. The regenerative
materials 550, however, may not stick to the fixed cutter drill bit
body 504 permanently due to the frictional forces created by
circulation of the drilling fluid and movement of the bit relative
to the wellbore and cuttings in the drilling fluid. Nonetheless,
constant magnetic attraction of the regenerative materials 550 to
the magnetic particles 545 may increase the longevity of the fixed
cutter drill bit 500 by forming a protective nanofilm that
insulates the surface of the drill bit body as described above with
regard to the roller cone 304 of FIG. 3. In the case of a chip 560
or crack 565 that is filled by regenerative materials 550, it is
noted that increased bonding may occur due to the roughened surface
of the bit body 504 resulting from the non-smooth crack 545 or chip
560 in the material. Regenerative materials 550 that are
magnetically attracted to areas such as chip 560 or crack 565 may
thereby provide a more complete filling of chip 560 or crack 565.
Also, the filling of such areas with regenerative materials 550 and
formation of a protective nanofilm will further insulate and
protect the surface of the fixed cutter bit 500 by preventing
damaging particles from entering the areas of the crack 565 and
chip 560.
[0034] FIG. 6 illustrates a cross-section of the fixed cutter drill
bit 500 of FIG. 5 and shows the migration of regenerative materials
550 into the chip 560 and crack 565 in the manner described above
with regard to FIGS. 3 and 4. The magnetic particles 545 attract
the regenerative materials 550 so that regenerative nanoparticles
550A are attracted into the chip 560 and crack 565 to form a
repaired drill bit 500. This process may occur continuously and
repeatedly during drilling.
[0035] As described above in relation to the roller cone bit body
304 of FIGS. 3 and 4, the fixed cutter bit body 500 may be formed
according to known sintering, casting, and other suitable
fabrication techniques. For example, a particulate phase including
a powder such as tungsten carbide and rare earth magnets that form
the magnetic material 540 may be mixed with binder material to form
the body of the drill bit 500. This mixture may be placed in a mold
for sintering and heated to form the drill bit body.
[0036] In an embodiment, magnetic particles of the types described
previously are formed or magnetized in situ in a drill bit body by
heating a magnetizable material above its Curie temperature,
putting the heated material in an electromagnetic field, and then
cooling. This may be performed during the infiltration of binder
material into a particulate phase that includes a hard material
powder and magnetizable material during, for example, a sintering
fabrication process. In an embodiment, the sintering fabrication
process is used to heat the magnetizable material to or above its
Curie temperature. Magnetization may be achieved by applying a
magnetic field to the magnetizable material at the Curie
temperature as the bit body is being cooled. In an embodiment, the
material is magnetized during the cooling process instead of at a
prior time during the fabrication process to minimize the effects
of material migration that may occur if the binder has increased
permeability at higher temperatures. To magnetize the magnetic
particles, an electromagnetic field is applied to the drill bit
when the material is at the Curie temperature for the material to
be magnetized. Examples of some relevant Curie temperatures for
suitable magnetic materials are: FE 770.degree. C. for iron; Co
1130.degree. C. for cobalt; Ni 358.degree. C. for nickel; and
622.degree. C. for iron oxide.
[0037] In another embodiment, magnetizable materials such as
superparamagnetic nanoparticles in the drilling fluid may be used
to identify leak-off zones in a wellbore using magnetic resonance
imaging (MRI) or nuclear magnetic resonance imaging (NMR) in a
logging while drilling (LWD) process. Since the superparamagnetic
nanoparticles will be circulated throughout the drill string and
wellbore in the drilling fluid, and because such nanoparticles
carry a very strong magnetic charge with a single pole, the
nanoparticles are easily detectable by such imaging systems. In
some embodiments, leaching drilling fluid may be detected via
MRI/NMR systems that detect the superparamagnetic nanoparticles in
the drilling fluid.
[0038] In some embodiments, if a non-matrix drill bit is used, then
small amounts of magnetic material may still be included in
portions of the drill bit. In the case of drill bits made of steel,
for example, the composition of the steel may be adjusted to
include iron that may be magnetically charged by applying a
magnetic field during formation at Curie temperatures as described
above. Rare earth magnets might also be used, but their magnetic
properties may be destroyed during the high temperatures used to
form steel. In such embodiments, permanent magnets or other
suitable magnets may be used to attract the regenerative
materials.
[0039] In another embodiment, as shown in the schematic drawing of
FIG. 7, a drill bit 604 may include or be coupled to an
electromagnet 606 that is deployed adjacent the drill bit 604 in a
drill string 608. The electromagnet 606 may be an assembly that is
integral to the assembly of the drill bit 604, or included within a
collar or other member of the drill sting 602 that is proximate to
the drill bit 604. In either case, the electromagnet is
magnetically coupled to the drill bit and operable to induce a
magnetic polarity in magnetic materials included in the drill bit
604, thereby causing the magnetic materials of the drill bit to
transmit a magnetic field. In an embodiment in which the drill
string 604 is also operable to detect leaching of drilling fluid by
monitoring the movement of superparamagnetic particles or other
magnetic particles in a drilling fluid, the drill string 602 also
includes a LWD module 610, which may be a MRI or NMR module that
may track or detect the presence of magnetic or superparamagnetic
particles at locations in the wellbore in which the module 610 is
deployed.
[0040] FIG. 8 is a block diagram showing elements of a portion of
the system described with regard to FIG. 7. As shown in FIG. 8, in
an illustrative embodiment, the electromagnet 706 includes an
electromagnet, which may be, for example, a conductive coil 714.
The electromagnet is magnetically coupled to the drill bit 704 to
apply a magnetic field that extends to (and beyond) the exterior of
the body of the drill bit, with sufficient magnitude to interact
with the regenerative nanoparticles in the drilling fluid flowing
over the surface of the drill bit. The amount of current and
voltage supplied to the conductive coil 714 is controlled by a
controller 704, which is in turn coupled to a power source 710. The
controller 704 may also be coupled to a transceiver 712, which may
be any suitable wired or wireless transceiver that communicatively
couples the controller 708 with a surface based controller for the
purposes of receiving an actuation signal that results in the
activation and deactivation of the electromagnet 714, and
optionally to control the magnitude of the magnetic field generated
by the electromagnet. The electromagnet 714 thus enables selective
magnetization of the drill bit body. The magnetic field may be
generated with sufficient magnitude to attract regenerative
nanoparticles and cause the regenerative nanoparticles to attach to
the surface of the drill bit body when the electromagnet is
operational. The selective magnetization may include selectively
reducing or deactivating the magnetic field, enabling the drill bit
to release the regenerative nanoparticles that had previously been
attached to the surface of the drill bit body so that the drill bit
and surrounding area may be flushed out when desired.
[0041] Applying the foregoing concepts, systems, and methods, it is
again noted that the duration of time a drill bit, such as a fixed
cutter drill bit, roller cone drill bit, or other type of drill
bit, will last without becoming heavily damaged is an important
factor in being able to continuously perform drilling operations.
By providing a drill bit that may regenerate or form a protective
film in the presence of regenerative materials (such as
regenerative nanoparticles circulated in drilling fluid), the
window for continuously performing drilling operations may be
expanded. This disclosure therefore describes systems, tools, and
methods for providing a regenerating drill bit that is capable of
attracting regenerative nanoparticles to repair and insulate the
surface of the drill bit body using magnetic materials embedded in
the drill bit body. In addition to the embodiments described above,
many examples of specific combinations are within the scope of the
disclosure, some of which are detailed in the following
examples:
Example 1
[0042] A wellbore formation system comprising: [0043] a drill bit
having at least one cutting element and a drill bit body comprising
a magnetized material that generates a magnetic field extending to
an exterior of the drill bit body; [0044] a drilling fluid
comprising magnetizable regenerative particles; and [0045] a fluid
flow path that guides the drilling fluid through a drill string and
over a surface of the drill bit.
Example 2
[0046] The system of example 1 wherein, the regenerative particles
comprise superparamagnetic nanoparticles.
Example 3
[0047] The system of example 2, wherein the superparamagnetic
nanoparticles comprise iron oxide.
Example 4
[0048] The system of example 1, wherein the drill bit body is a
matrix drill bit body, and wherein the matrix drill bit body
comprises: [0049] a particulate phase and a binder material, the
particulate phase comprising magnetic particles.
Example 5
[0050] The system of example 1, further comprising an
electromagnet, wherein the drill bit body is a matrix drill bit
body, and wherein the matrix drill bit body comprises: [0051] a
particulate phase and a binder material, the particulate phase
comprising ferromagnetic particles; and [0052] wherein the drill
bit is magnetically coupled to the electromagnet.
Example 6
[0053] The system of example 1, further comprising an
electromagnet, wherein the drill bit body is a matrix drill bit
body, and wherein the matrix drill bit body comprises: [0054] a
particulate phase and a binder material, the particulate phase
comprising particles of rare earth magnet.
Example 7
[0055] The system of example 6, wherein the rare earth magnet is
selected from the group consisting of AlNiCo, a neodymium magnet,
and a samarium-cobalt magnet.
Example 8
[0056] The system of example 1 wherein the drilling fluid is a
water-based drilling fluid, and wherein the regenerative materials
are functionalized for dissolution in water.
Example 9
[0057] The system of example 1 wherein the drilling fluid is an
oil-based drilling fluid, and wherein the regenerative materials
are functionalized for dissolution in oil.
Example 10
[0058] A method of preserving a drill bit surface, the method
comprising: [0059] providing a drill bit having a magnetized drill
bit body that generates a magnetic field extending to an exterior
of the drill bit body; [0060] operating the drill bit to form a
wellbore, the drill bit comprising the drill bit body; and [0061]
circulating a fluid over a surface of the drill bit body to
regenerate a surface of the drill bit body, the fluid comprising
regenerative materials that are magnetically attracted to the
magnetized drill bit body.
Example 11
[0062] The method of example 10, wherein the regenerative materials
comprise iron oxide nanoparticles.
Example 12
[0063] The method of example 10, wherein the regenerative materials
comprise superparamagnetic particles.
Example 13
[0064] The method of example 10, wherein the drill bit comprises a
matrix drill bit body having a particulate phase component, a
binder material, the particulate phase including tungsten carbide,
and the magnetic particles.
Example 14
[0065] The method of example 13, further comprising activating an
electromagnet, wherein the magnetic particles comprise a
ferromagnetic material that becomes magnetized in response to
activation of the electromagnet.
Example 15
[0066] The method of example 10, wherein the magnetic particles
comprise particles of rare earth magnet selected from the group
consisting of AlNiCo, neodymium magnet, and samarium-cobalt
magnet.
Example 16
[0067] The method of example 10, further comprising forming a
protective film of the regenerative materials at a surface of the
drill bit body by magnetically attracting the regenerative
materials to the surface of the drill bit body.
Example 17
[0068] A method of manufacturing a drill bit body comprising:
[0069] placing a particulate phase and a binder material into a
mold, the particulate phase including tungsten carbide and
magnetizable particles; and [0070] sintering the particulate phase
and the binder to form a drill bit body.
Example 18
[0071] The method of example 17, further comprising cooling the
drill bit body following the step of sintering the particulate
phase and the binder to form the drill bit body; and, while cooling
the drill bit body, applying a magnetic field to the drill bit
body.
Example 19
[0072] The method of example 18, wherein applying the magnetic
field to the drill bit body comprises applying a magnetic field to
the drill bit body when the magnetizable particles are at the Curie
temperature.
Example 20
[0073] The method of example 17, wherein the magnetizable particles
comprise particles of rare earth magnet selected from the group
consisting of AlNiCo magnet, a neodymium, and samarium-cobalt.
[0074] It should be apparent from the foregoing that embodiments
having significant advantages have been provided. While the
embodiments are shown in only a few forms, the embodiments are not
limited, but are susceptible to various changes and modifications
without departing from the spirit thereof.
* * * * *