AIR MOTOR ASSEMBLY
An air motor apparatus for air drilling includes a filter assembly at an uphole end that receives compressed air and diverts a constant pressure portion through a filter to a vane motor and a remaining portion to an air hammer at a downhole end via bypass conduits. The apparatus includes one or more sensors for measuring drilling conditions, the sensors being connected to a communication device capable of transmitting the sensor data to the surface. The sensors and their wiring are shielded from high air speeds by bypass conduits and components of the filter assembly.
This application is a continuation of U.S. Nonprovisional patent application Ser. No. 19/084,298, filed on Mar. 19, 2025, which claims priority to U.S. Provisional Patent Application No. 63/567,575, filed on Mar. 20, 2024, entitled “AIR MOTOR ASSEMBLY,” the disclosure of which is herein incorporated by reference in its entirety.
TECHNICAL FIELDThe present disclosure relates to an air motor for air drilling and other borehole operations, such as wellbore cleanout. More particularly, the disclosure provides an air motor that may be used with an air hammer, the air motor configured to protect sensitive electrical components and allow for real time monitoring of a borehole operation.
BACKGROUNDUnderground directional drilling has been largely limited to drilling with roller cone or polycrystalline diamond compound (PDC) type bits with mud or air-mist rotary drilling motors utilizing rotor-stator or similar technologies. These technologies use liquid-based drilling fluids, which are not conducive to wireless telemetry for real time monitoring of the drilling operation. Portions of the drilling industry use air hammer drilling tools, also known as drill hammers, for conventional straight-hole drilling that strictly use air as the drilling medium. However, rotor-stator technology is not suitable for air hammer drilling tools. Consequently, the air hammer drilling industry has had limited access to the benefits of directional drilling.
Embodiments of the subject matter are disclosed with reference to the accompanying drawings and are for illustrative purposes only. The subject matter is not limited in its application to the details of construction, or the arrangement of the components illustrated in the drawings. Like reference numerals are used to indicate like components, unless otherwise indicated.
The following descriptions are provided to explain and illustrate embodiments of the present disclosure. The described examples and embodiments should not be construed to limit the present disclosure.
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In operation, the compressed air stream flows to the filter canister 112 and initially impacts a filter cone 112a. In some embodiments, the filter canister 112 includes cyclone generating features 112b to rotate and accelerate the compressed air. The features 112b may include spiral vanes or grooves configured to generate a cyclone. The effect of the features 112b is to spin the air stream, thereby ejecting particulate matter within the air stream outward and away from the air inlet ports 112c leading to the filter 113. This action reduces the buildup of grit on the filter 113, extending its life.
The filter canister 112, which is shown in isolation in
An enlarged view of the communication hub 117 according to an embodiment is shown in
Referring again to
In some embodiments, the filter assembly housing 119 or the regulator sub 118 may include one or more jet ports 119b upstream of the motor assembly 120 to allow for additional air volume and pressure to be transmitted down the drill pipe and be exhausted into the borehole above the hammer and motor assembly 120 for better bore hole cleaning. Most air drilling rigs operate air compression systems at 350 psi or less, and 1250 cfm or less. When encountering fluids in the well bore, many drillers will increase their air volume and pressure with air boosters in order to help clean out the hole. This increase will often exceed the recommended air flow and pressure requirements for the air hammer causing damage to the hammer and bit. Jet ports 119b, in the form of built-in pressure relief valves set at 350 psi, may be built into the top sub apparatus 100. The jet ports 119b will only open when the air pressure inside the drill pipe exceeds the set pressure of the valves. This allows most of the additional air, provided by the booster, to be exhausted above the motor. This exhausted air will bypass the air hammer yet still provide for the additional hole cleaning.
In some embodiments, the filter assembly 110 may include one or more sensors 1102 in communication with the communication hub 117. The sensors 1102 may include accelerometers and/or inclinometers or other low power sensors such as a Micro Electromechanical System (MEMs) gyroscope placed to measure tilt and roll of the apparatus 100. The sensors 1102 can be fixed at a precise tilt angle and oriented with the adjustable bent sub assembly 130 so the face direction of the apparatus 100 will always be known relative to the drill string orientation. This is particularly useful during the initial kickoff phase of the drilling, so the bit direction at the bottom of the hole can be accurately oriented. The sensors 1102 may also measure the rotation of the entire bottom assembly both for RPM and smoothness of the rotation when the driller is rotating the entire drill string. This is particularly useful when the drill string is long and the driller is unable to sense these parameters.
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Filtered air from the filter outlet 115 passes to a regulator 1204. The regulator 1204 can be set to a desired pressure, e.g., about 90 psi, and thereby provides a constant pressure to the vane motor 1210 via a manifold 1205, which can in turn provide steady rotation speed to the air hammer regardless of the incoming compressed air pressure (though inlet 111). Power generated by the motor 1210 is transferred to the gear assembly 1216 (e.g., a planetary gear assembly) which in turn drives an output 1212 (e.g., a square drive or universal joint) that is linked to the adjustable bent sub assembly 130.
Rotation speed for pneumatic hammer operations may be capped between 30 to 50 RPM. Maximum rotational speed is pre-determined by the regulator 1204 setting inside the motor assembly 120 and the initial vane motor 1210 and gear assembly 1216 configuration. This rotation is independent of fluctuations in air volume or pressure (from inlet 111). Only a small, fixed portion of the air that flows down the drill pipe is required for the power section of the vane motor 1210, while the remaining air is bypassed down to the hammer and bit via bypass tubes 1208, which are in communication with filter bypass 114 of the filter assembly 110. The bypass tubes 1208 are further in communication with motor bypass 1214, which guides the air stream to the adjustable bent sub assembly 130 (and eventually to the hammer).
Operation of the apparatus 100 is distinct from positive displacement motors (PDMs), which will speed up or slow down their rotation speed with increases or decreases of air pressure and air volume. This is because all of the air that flows down the drill pipe and through the bit flows through the power section of the PDM. High air flows will cause high rotation speeds that can cause excessive damage or damage to drill bits and can wear out or damage the elastomer inside the PDM. When a PDM stalls on the bottom of a hole, air flow is halted, and air pressure increases inside the drill string. A rapid and excessive runaway rotation can occur when the tool is lifted off the bottom. This can cause damage to the assembly. More damage can occur when the motor touches back down on the bottom of the hole when the motor is rotating excessively. The motor 1210 of the present disclosure will rotate gradually up to speed to its set maximum rotation speed (e.g., approximately 30 RPM) when lifting off the bottom after a stall. Any air flow increase due to the release of pressurized air inside the drill string during a stall passes through to the hammer and aids in hole cleaning which is a positive result.
The motor assembly 120 may include one or more sensors for monitoring drilling conditions. For example, a speed sensor 1220 may be positioned downhole of the motor 1210 (e.g., between the motor 1210 and the gear assembly 1216) to monitor the rotational speed of the motor 1210. Wiring 117g may connect the speed sensor 1220 to the communication hub 117 and may utilize spaces between the bypass tubes 1208 to protect the wiring 117g from the air stream. That is, bypass tubes 1208 send the high velocity air past the vane motor chamber 1210a. The design provides for additional space for sensors and wiring to be located inside the vane motor chamber 1210a so that they are protected from the violent compressed air stream flowing down to the hammer. Sensors that measure air pressure, temperature, shock and vibration, and motor rotation speed can be placed within this chamber 1210a or adjacent to the chamber 1210a. These sensors will provide the driller with instantaneous critical information regarding the motor performance.
For example, in some embodiments, one or more pressure and/or temperature sensors may be positioned within the motor assembly 120 and in communication with the communication hub 117, e.g., via wiring 117g or via wireless communication. For example, a pressure sensor 1224 can be positioned within the motor housing 1202 to measure a borehole pressure or an ambient pressure and a pressure sensor 1222 can be positioned within the air stream bypassing the filter 113 (i.e., the air pressure to be delivered to the air hammer). The communication hub 117 can relay information from the sensors 1220, 1222, 1224 to the surface to provide real time monitoring of the drilling operation, and the data transmitted may be accurately time stamped. Should a failure occur, the moment of failure can be accurately noted with the sensor data. This can greatly aid both the driller and manufacturer with the ability to diagnose the failure and take corrective steps to either continue on with drilling, or to modify future components to mitigate future failures.
With reference to
An additional view of the motor canister 1230 is shown in
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In any embodiment, additional sensors can be placed within the motor housing 1202 and be in communication with the communication hub 117. Any combination of the sensors and sensor positioning described in
The various sensors disclosed herein in combination with the communication hub 117 can provide critical information to drillers allowing them to understand downhole conditions in real time and to optimize drilling. This sensor capability can enhance the drilling efficiency and warn of potential motor failure conditions before a failure occurs. Some sensors can also detect borehole conditions and serve as early warnings when dangerous gas is encountered. Several components of the apparatus 100 disclosed herein serve a dual function, being a component for the motor 1210 to function and as a location for the placement of sensors and other electronics. Sensors measuring motor rotation, air pressure both inside and outside the motor, temperature both inside and outside the motor, and shock and vibration may be placed within the apparatus 100.
The apparatus 100 comprises a gear and vane driven motor 1210 that rotates nearly vibration free. PDMs combined with air hammers can cause excessive vibration on the downhole assemblies. Excessive vibration also leads to the failure of the electrical components for many types of downhole measurement devices such as EM and GR tools. The design of the apparatus 100 provides low vibration while also shielding electrical components from compressed air, thereby enabling reliable, real time monitoring of drilling operations.
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In one or more embodiments, the apparatus 100 of the present disclosure may have an outer diameter of about 3″, about 4″, about 6″, about 8″, about 10″, about 12″, between about 4″ and about 8″, between about 3″ and about 10″, or between about 3″ and about 12″. Any other suitable size may be employed and the apparatus 100 may be appropriately scaled. In some embodiments, the apparatus 100 is configured to fit within a 5.5″ cased well (e.g., a 4″ outer diameter). In some embodiments, the apparatus 100 may be used for cleanout operations, such as well cleanout. In this regard, one of the main reasons for low productivity over time from older wells is the buildup of very hard scale inside the casing. Operators need to clean out this scale to increase or restore productivity. Coiled tubing units are typically employed for this task. The PDC and PDM combination used with coiled tubing can often breach the casing since significant weight on the bit must be applied in order to cut through the hard scale. Unfortunately, PDC bits can drill into and possibly through the wall of the softer casing when this bit weight is applied. The loss of the well is possible when this happens. Since the air hammer and air motor combination described herein requires very little weight on the bit for effective drilling, the drilling action can be confined inside the casing and not breach the casing. Also, down the hole (DTH) hammers are very effective in hard formations. Consequently, the air motor and air hammer combination has the ability to drill out this hard scale while not breaching the casing.
Additionally, the apparatus 100 disclosed herein may provide for low rotational and makeup torque and may have a short length. The short tool length allows for the apparatus 100 to be made up within short tower conventional rigs and small horizontal directional drilling (HDD) rigs. Large fleets of small top drive rigs routinely and exclusively drill with air hammers. The short length apparatus 100 allow small rigs to drill deviated and horizontal holes with conventional air hammers. Further, drill rigs may not need high torque makeup tools to employ the apparatus 100 of the present disclosure. The bottom hole assembly can be made up with the equivalent torque that is routinely applied during drill string makeup. That torque is typically generated by the top drive for most pull down rigs. High rotational torque is not required for DTH pneumatic hammers to operate. The cutting action for the DTH bit is supplied by the impact of the buttons of the bit on the formation and not by a scraping mechanism employed by PDC bits. Rotational torque for DTH hammers is only necessary to ensure the buttons on the bit are striking in new spots on the bottom of the hole. The short length and low rotational and makeup torque in combination with the low weight on the bit make the apparatus 100 ideal for small HDD rigs, particularly in very hard rock drilling situations.
The apparatus 100 may also be used in high temperature drilling (e.g., geothermal) because the components thereof can withstand or be insulated from high borehole temperatures. This ability allows for the use of the apparatus in high temperature geothermal drilling applications. On the other hand, PDMs have temperature limitations due to the elastomers used in the power section of the motor.
Although mechanical valves have been disclosed herein, any one or more of the valves of the apparatus 100 may be a remotely controlled valve (e.g., a solenoid valve). The sensors and telemetry system disclosed may be used to communicate with and control such valves.
Although the present disclosure has been described using preferred embodiments and optional features, modification and variation of the embodiments herein disclosed can be foreseen by those of ordinary skill in the art, and such modifications and variations are considered to be within the scope of the present disclosure. It is also to be understood that the above description is intended to be illustrative and not restrictive. Many alternative embodiments will be apparent to those of ordinary skill in the art upon reviewing the above description. Additionally, the terms and expressions employed herein have been used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the future shown and described or any portion thereof, and it is recognized that various modifications are possible within the scope of the disclosure.
Claims
1. An apparatus comprising:
- a tubular housing comprising an inlet at an uphole end configured to receive pressurized air and an outlet at a downhole end;
- a filter housing within the tubular housing;
- a filter positioned within the filter housing and configured to receive a first portion of the pressurized air via a filter inlet of the filter housing;
- a communication device within the filter housing;
- a vane motor downhole of the filter and configured to receive the first portion of the pressurized air from the filter;
- an air bypass conduit positioned about the vane motor and configured to direct a second portion of the pressurized air past the vane motor;
- a sensor positioned downhole of the filter; and
- wiring connecting the sensor to the communication device, wherein the wiring is isolated from the second portion of the pressurized air by the air bypass conduit.
2. The apparatus of claim 1, further comprising a motor canister positioned about the vane motor;
- wherein the air bypass conduit is formed between the tubular housing and the motor canister; and
- wherein the wiring is disposed at least partially within the motor canister.
3. The apparatus of claim 2, wherein the motor canister comprises a valve configured to exhaust air from the vane motor out of the tubular housing.
4. The apparatus of claim 1, wherein the air bypass conduit comprises a plurality of tubes and wherein the wiring is disposed at least partially within interstices between the plurality of tubes.
5. The apparatus of claim 1, wherein the communication device is a wireless communication device.
6. The apparatus of claim 5, wherein an upstream end of the filter housing comprises a material through which a signal from the wireless communication device can pass.
7. The apparatus of claim 5, wherein the wireless communication device comprises a microwave transmitter and an upstream end of the filter housing comprises a material that is transparent to microwaves.
8. The apparatus of claim 1, wherein the sensor is a gyroscope.
9. The apparatus of claim 1, wherein the sensor is a pressure sensor.
10. The apparatus of claim 1, further comprising a gas detection system comprising a gas sampling chamber and a gas sensor within the gas sampling chamber;
- wherein the tubular housing comprises a port in fluid communication with the gas detection system, the port being configured to introduce a sample gas from an exterior of the tubular housing into the gas sampling chamber;
- wherein the gas sensor is in communication with the communication device; and
- wherein the gas detection system is at least partially isolated from the second portion of the pressurized air by the air bypass conduit.
11. The apparatus of claim 10, wherein the gas sensor is configured to detect combustible gases, H2S gas, or a combination thereof.
12. The apparatus of claim 10, wherein the gas detection system comprises a venturi nozzle configured receive air from the first portion of the pressurized air and create a vacuum to draw the sample gas through the port and into the gas sampling chamber.
13. A system comprising:
- the apparatus of claim 1,
- an air compressor configured to generate and deliver the pressurized air to the inlet of the apparatus; and
- an air hammer connected to the outlet of the apparatus; and
- wherein the apparatus is configured to direct the second portion of the pressurized air to the air hammer.
14. The system of claim 13, wherein the second portion of the pressurized air drives an axial motion of the air hammer, and the first portion of the pressurized air drives a rotational motion of the air hammer via the vane motor.
15. The system of claim 14, wherein the apparatus comprises a regulator configured to maintain a constant pressure of the first portion of the pressurized air.
16. The system of claim 13, further comprising a drill string connected to the uphole end of the apparatus.
17. A method, comprising:
- directing pressurized air to an apparatus positioned within a borehole;
- driving a vane motor with a first portion of the pressurized air;
- using a sensor, measuring an operational parameter of the apparatus;
- transmitting data related to the operational parameter from the sensor to a communication device positioned uphole of the sensor; and
- using the communication device, wirelessly transmitting the data to a receiver positioned uphole of the communication device.
18. The method of claim 17, further comprising:
- diverting a second portion of the pressurized air through an air bypass conduit past the vane motor;
- wherein transmitting the data comprises using wiring connecting the sensor to the communication device; and
- wherein the wiring is isolated from the second portion of the pressurized air via the air bypass conduit.
19. The method of claim 17, wherein the sensor comprises a speed sensor, a gas sensor, or a gyroscope.
20. The method of claim 18, further comprising:
- directing the second portion of the pressurized air to an air hammer downhole of the vane motor;
- driving an axial motion of the air hammer with the second portion of the pressurized air; and
- driving a rotational motion of the air hammer via the vane motor.
Type: Application
Filed: Jul 29, 2025
Publication Date: Nov 20, 2025
Inventors: Michael P. Sanders (Lexington, KY), Michael K. Smith (Midland, TX)
Application Number: 19/284,136