Patent Application
20150267472
The present disclosure relates to drill bits, drill bit materials, and related methods of use.
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.”
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.
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.
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.
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.
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.
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:
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.
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.
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.
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.
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.
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 (γ-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.
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.
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.
Referring now to the figures,
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.
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.
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° C. to 550° C. for AlNiCo; below 200° C. for NdFeB; and from 250° C. to 350° 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° C., for example, AlNiCo may be the appropriate rare earth magnet for use in the bit body.
Referring now to
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
As described above in relation to the roller cone bit body 304 of
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° C. for iron; Co 1130° C. for cobalt; Ni 358° C. for nickel; and 622° C. for iron oxide.
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.
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.
In another embodiment, as shown in the schematic drawing of
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:
A wellbore formation system comprising:
The system of example 1 wherein, the regenerative particles comprise superparamagnetic nanoparticles.
The system of example 2, wherein the superparamagnetic nanoparticles comprise iron oxide.
The system of example 1, wherein the drill bit body is a matrix drill bit body, and wherein the matrix drill bit body comprises:
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:
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:
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.
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.
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.
A method of preserving a drill bit surface, the method comprising:
The method of example 10, wherein the regenerative materials comprise iron oxide nanoparticles.
The method of example 10, wherein the regenerative materials comprise superparamagnetic particles.
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.
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.
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.
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.
A method of manufacturing a drill bit body comprising:
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.
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.
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.
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.
