During conventional measuring while drilling (MWD) or logging while drilling (LWD) operations, signals are passed between a surface unit and the BHA to transmit, for example commands and information. Typical telemetry systems involve mud-pulse telemetry that uses the drill pipe as an acoustic conduit for mud pulse telemetry. With mud pulse telemetry, mud is passed from a surface mud pit and through the pipes to the bit. The mud exits the bit and is used to contain formation pressure, cool the bit, and lift drill cuttings from the borehole. This same mud flow is selectively altered to create pressure pulses at a frequency detectable at the surface and downhole. Typically, the operating frequency is in the order 1-3 bits/sec, but can fall within the range of 0.5 to 6 bits/sec.
In conventional drilling, a well is drilled to a selected depth with drill pipe, and then the wellbore is typically lined with a larger-diameter pipe, usually called casing. Casing typically includes casing sections connected end-to-end, similar to the way drill pipe is connected. To accomplish this, the drill string and the drill bit are removed from the borehole in a process called “tripping.” Once the drill string and bit are removed, the casing is lowered into the well and cemented in place. The casing protects the well from collapse and isolates the subterranean formations from each other. After the casing is in place, drilling may continue or the well may be completed depending on the situation.
Conventional drilling typically includes a series of drilling, tripping, casing and cementing, and then drilling again to deepen the borehole. This process is very time consuming and costly. Additionally, other problems are often encountered when tripping the drill string. For example, the drill string may get caught up in the borehole while it is being removed. These problems require additional time and expense to correct.
The term “casing drilling” refers to the use of a casing string in place of a drill string which uses drill pipe. Like the drill string, a chain of casing sections are connected end-to-end to form a casing string. The BHA and the drill bit are connected to the lower end of a casing string, and the well is drilled using the casing string to transmit drilling fluid, as well as axial and rotational forces, to the drill bit. Upon completion of drilling, the casing string may then be cemented in place to form the casing for the wellbore. Casing drilling enables the well to be simultaneously drilled and cased.
Existing casing drilling systems that employ directional MWD and/or LWD assemblies have several drawbacks. A downhole drilling motor is typically used due to rotational limitations of the casing and provides power for rotation of the BHA, including the bit to drill the pilot hole and the under-reamer to enlarge the hole for the casing to pass. The downhole drilling motor typically includes a positive displacement mud motor (PDM) or turbodrill. In a directional/logging BHA for casing drilling, high speed mud pulse telemetry is seriously degraded and attenuated due to the operation of the drilling motor. Accordingly, there remains a need in the art for improved bottom hole assemblies (BHAs) for casing drilling systems.
A casing drilling bottom hole assembly (BHA) may include a modulator and turbine power generation system, a wireless power and data connection, and a rotary steerable system (RSS). The modulator and turbine power generation system is coupled to a casing. The wireless power and data connection is coupled to a downhole end of the high speed modulator and turbine power generation system for providing power and data connectivity between the high speed modulator and turbine power generation system and a drilling motor. The RSS is coupled to the drilling motor for receiving power from and communicating with the high speed modulator and turbine power generation system via the wireless power and data connection and the drilling motor.
This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.
In the Figures, like reference numerals refer to like parts throughout the various views unless otherwise indicated. For reference numerals with letter character designations such as “102A” or “102B”, the letter character designations may differentiate two like parts or elements present in the same figure. Letter character designations for reference numerals may be omitted when it is intended that a reference numeral to encompass parts having the same reference numeral in figures.
The system described below mentions how power and/or communications may flow from an Measurement While Drilling (MWD) power system through a positive displacement motor to a rotary steerable system (“RSS”) and/or Logging While Drilling systems. One of ordinary skill in the art recognizes that communications may easily flow in the other direction—from the RSS and/or LWD equipment to the MWD system.
Referring initially to
The controller 106 further includes a display 147 for conveying alerts 110A and status information 115A that are produced by an alerts module 110B and a status module 115B. The controller 106 in some instances may communicate directly with the drilling system 104 as indicated by dashed line 99 or the controller 106 may communicate indirectly with the drilling system 104 using the communications network 142
The controller 106 and the drilling system 104 may be coupled to the communications network 142 via communication links 103. Many of the system elements illustrated in
A drill string 12 is suspended within the borehole 11 and has a bottom hole assembly (“BHA”) 100 which includes a drill bit 105 at its lower end. The surface system includes platform and derrick assembly 10 positioned over the borehole 11, the assembly 10 including a rotary table 16, kelly 17, hook 18 and rotary swivel 19. The drill string 12 is rotated by the rotary table 16, energized by means not shown, which engages the kelly 17 at the upper end of the drill string. The drill string 12 is suspended from a hook 18, attached to a traveling block (also not shown), through the kelly 17 and a rotary swivel 19 which permits rotation of the drill string 12 relative to the hook 18. As is known to one of ordinary skill in the art, a top drive system could alternatively be used instead of the kelly 17 and rotary table 16 to rotate the drill string 12 from the surface. The drill string 12 may be assembled from a plurality of segments 125 of pipe and/or collars threadedly joined end to end.
In the embodiment of
The BHA 100 of the illustrated embodiment may include a logging-while-drilling (“LWD”) module 120, a measuring-while-drilling (“MWD”) module 130, a roto-steerable system (“RSS”) and motor 150 (also illustrated as 280 in
The LWD module 120 is housed in a special type of drill collar, as is known to one of ordinary skill in the art, and can contain one or a plurality of known types of logging tools. It will also be understood that more than one LWD 120 and/or MWD module 130 can be employed, e.g. as represented at 120A. (References, throughout, to a module at the position of 120A can alternatively mean a module at the position of 120B as well.) The LWD module 120 includes capabilities for measuring, processing, and storing information, as well as for communicating with the surface equipment. In the present embodiment, the LWD module 120 includes a directional resistivity measuring device.
The MWD module 130 is also housed in a special type of drill collar, as is known to one of ordinary skill in the art, and can contain one or more devices for measuring characteristics of the drill string 12 and drill bit 105. The MWD module 130 may further include an apparatus (not shown) for generating electrical power to the BHA 100.
This apparatus may include a mud turbine generator powered by the flow of the drilling fluid 26, it being understood by one of ordinary skill in the art that other power and/or battery systems may be employed. In the embodiment, the MWD module 130 includes one or more of the following types of measuring devices: a weight-on-bit measuring device, a torque measuring device, a vibration measuring device, a shock measuring device, a stick slip measuring device, a direction measuring device, and an inclination measuring device.
The foregoing examples of wireline and drill string conveyance of a well logging instrument are not to be construed as a limitation on the types of conveyance that may be used for the well logging instrument. Any other conveyance known to one of ordinary skill in the art may be used, including without limitation, slickline (solid wire cable), coiled tubing, well tractor and production tubing.
The casing drilling system 200 may include casing 404 that couples with a BHA 100 via a drilling latch assembly (“DLA”) 406. The DLA 406 may coupled with an under-reamer 412 that is also attached to a drill bit 105. The under-reamer 412 may form the reamed hole 418 which has a diameter which is greater than the diameter of the pilot hole 416 for by the drill bit 105.
The casing drilling system 200 may further include conductor pipe 491 which may surround and protect the casing 404 near the Earth's surface. The casing drilling system 200 may further include casing slips 444, a casing drive head/assembly 441, draw works 442, and a guide rail and top drive/block dolly 443 as understood by one of ordinary skill the art. Further details of a modified BHA 100 having wireless power and data connections 402 for the casing drilling system 200 will be described below in connection with
k=M/√{square root over (L1L2)} (1)
While a conventional inductive coupler has k≈1, weakly coupled coils may have a value for k less than 1 such as, for example, less than or equal to about 0.9. To compensate for weak coupling, the primary and secondary coils in the various embodiments are resonated at the same frequency. The resonance frequency is calculated as:
At resonance, the reactance due to L1 is cancelled by the reactance due to C1. Similarly, the reactance due to L2 is cancelled by the reactance due to C2. Efficient power transfer may occur at the resonance frequency, f0=ω0/2π. In addition, both coils may be associated with high quality factors, defined as:
The quality factors, Q, may be greater than or equal to about 10 and in some embodiments greater than or equal to about 100. As is understood by one of ordinary skill in the art, the quality factor of a coil is a dimensionless parameter that characterizes the coil's bandwidth relative to its center frequency and, as such, a higher Q value may thus indicate a lower rate of energy loss as compared to coils with lower Q values.
If the coils are loosely coupled such that k<1, then efficient power transfer may be achieved provided the figure of merit, U, is larger than one such as, for example, greater than or equal to about 3:
U=k√{square root over (Q1Q2)}>>1. (4)
The primary and secondary circuits are coupled together via:
V
1
=jωL
1
I
1
+jωMI
2 and V2=jωL2I2+jωMI1, (5)
where V1 is the voltage across the transmitting coil. Note that the current is defined as clockwise in the primary circuit and counterclockwise in the secondary circuit. The power delivered to the load resistance is:
while the maximum theoretical power output from the fixed voltage source VS into a load is:
The power efficiency is defined as the power delivered to the load divided by the maximum possible power output from the source,
In order to optimize the power efficiency, η, the source resistance may be matched to the impedance of the rest of the circuitry. Referring to
When ω=ω0, Z1 is purely resistive and may equal RS for maximum efficiency.
Similarly, the impedance seen by the load looking back toward the source is
When ω=ω0, Z2 is purely resistive and RL should equal Z2 for maximum efficiency
The power delivered to the load is then:
and the power efficiency is the power delivered to the load divided by the maximum possible power output,
The optimum values for RL and RL may be obtained by simultaneously solving
with the result that:
R
S
=R
1√{square root over (1+k2Q1Q2)} and RL=R2√{square root over (1+k2Q1Q2)}. (16)
If the source and load resistances do not satisfy equations (16), then it is envisioned that standard methods may be used to transform the impedances. For example, as shown in the
Turning now to
Returning to
The receiving coil 232 may be free to move in the axial (z) direction or in the transverse direction (x) with respect to the transmitting coil 234. In addition, the receiving coil 232 may be able to rotate on axis with respect to the transmitting coil 234. The region between the two coils 232, 234 may be filled with air, fresh water, salt water, oil, natural gas, drilling fluid (known as “mud”), or any other liquid or gas. The transmitting coil 234 may also be mounted inside a metal tube, with minimal affect on the power efficiency because the magnetic flux may be captured by, and returned through, the ferrite shell 238 of the transmitting coil 234.
The operating frequency for these coils 232, 234 may vary according to the particular embodiment, but, for the
The variation in k versus axial displacement of the receiving coil 232 when x=0 may be relatively small, as illustrated by the graph 250 in
The power efficiency may also be calculated for displacements from the center in the z direction in mm (as illustrated by the graph 254 in
Referring now to
It is also envisioned that power may be transmitted from the inner coil to the outer coil of particular embodiments, interchanging the roles of transmitter and receiver. It is envisioned that the same power efficiency would be realized in both cases.
Referring to
Turning to
In lieu of, or in addition to, passing power, data signals may be transferred from one coil to the other in certain embodiments by a variety of means. In the above example, power is transferred using an about 100.0 kHz oscillating magnetic field. It is envisioned that this oscillating signal may also be used as a carrier frequency with amplitude modulation, phase modulation, or frequency modulation used to transfer data from the transmitting coil to the receiving coil. Such would provide a one-way data transfer.
An alternative embodiment includes additional secondary coils to transmit and receive data in parallel with any power transmissions occurring between the other coils described above, as illustrated in
The secondary data coils 266, 268 may be orthogonal to the power coils 232, 234, as illustrated in
Moreover, it is envisioned that the data coils 266, 268 may be wound on a non-magnetic dielectric material in some embodiments. Using a magnetic core for the data coils 266, 268 might result in the data coils' cores being saturated by the strong magnetic fields used for power transmission. Also, the data coils 266, 268 may be configured to operate at a substantially different frequency than the power transmission frequency. For example, if the power is transmitted at about 100.0 kHz in a certain embodiment, then the data may be transmitted at a frequency of about 1.0 MHz or higher. In such an embodiment, high pass filters on the data coils 266, 268 may prevent the about 100.0 kHz signal from corrupting the data signal. In still other embodiments, the data coils 266, 268 may simply be located away from the power coils 232, 234 to minimize any interference from the power transmission. It is further envisioned that some embodiments may use any combination of these methods to mitigate or eliminate adverse effects on the data coils 266, 268 from the power transmission of the power coils 232, 234.
The BHA 100 includes drilling latch assembly (“DLA”) 406 for coupling the BHA 100 to a casing 404. The BHA 100 further includes a casing drilling modulator and turbine power system 408, a wireless power and data connection 402, a drilling motor 410, an under-reamer 412, an RSS/MWD/LWD assembly 414 (see also LWD 120 and MWD 130 of
The casing drilling modulator and turbine power system 408 is located below the drilling latch assembly (“DLA”) 406 with a downhole end connected to the drilling motor 410. As understood by one of ordinary skill the art, the DLA 406 allows the turbine power system 408 and remaining equipment downward through the drill bit 105 to be retrieved and withdrawn through the casing 404 when the appropriate depth has been reached. Specifically, the diameter of the drill bit 105 is smaller than the inner diameter of the casing 404. In this way, the casing 404 generally remains in place after drilling operations have ceased such that equipment from the turbine power system 408 may be retrieved upward and through the casing 404. The DLA 406 also forms a fluid tight seal between the turbine power system 408 and the casing 404 so that fluid, such as mud, does not leak between the casing 404 in the turbine power system 408.
Power and data pass through the wireless power and data connection 402 between the modulator and turbine power system 408 and the drilling motor 410. The under-reamer 412, the RSS/MWD/LWD assembly 414, and the drill assembly 105 may be located below the drilling motor 410. As understood by one of ordinary skill in the art, positioning units requiring power and/or communications below a drilling motor 410 has not been possible previously because of the need for power generation with these units, such as the MWD module 130 and LWD module 120.
The under-reamer 412 may include a wired, collapsible under-reamer. The RSS/MWD/LWD assembly 414 generally includes a rotary steerable system (RSS) 150, the MWD module 130, and the LWD module 120. The wireless power and data connection 402 may include a wireless, tuned-inductive coupler mechanism for passing both power and data communications to downhole components of the BHA 100. It should be appreciated that separate coils may be used for power and communication transmissions. The wireless power and data connection 402 may allow the RSS module 414 to receive power from the turbine power system 408. Meanwhile, in conventional BHA assemblies, RSS modules 414 may have their own internal power source. The RSS modules 414 of the BHA 100 of this disclosure may have their own power source but also have the option of being powered by the turbine power system 408 through the wireless power and data connection 402.
The wireless power and data connection 402 allows relative motion between the modulator and turbine power system 408 (which is coupled to an external housing of the drilling motor 410) and a rotor of the drilling motor 410 (which is wired and coupled to the under-reamer 412, the RSS/MWD/LWD assembly 414, and the drill bit assembly 105), allowing power and data transfer throughout the entire BHA 100.
Power and data wiring exits the downhole end of the modulator and turbine power system 408 and is coupled to a stationary coil 502 of the wireless power and data connection 402 located in the drilling motor 410 external housing. Power and data is transmitted between the stationary coil 502 and a rotating coil 504 via tuned-inductive methods, as described above and illustrated in
The power system 408 and stationary coil 502 track whatever movement may exist with the casing 404. In some instances, the casing 404 may have some slight rotation at low revolutions per minute (“RPM”) relative to the borehole and therefore, the stationary coil 502 may follow this rotational movement of the casing 404. Meanwhile, the rotating coil 404 rotates with the drilling motor 410, and specifically the wired rotor 506, which rotates at significantly higher RPMs in order to rotate the drill assembly 105 as understood by one of ordinary skill in the art.
At the bottom of the rotor 506, the wire is terminated at a connection 508 to the rotating BHA. The connection may include a threaded rotary shouldered joint and a sealed electrical connector mechanically and electrically coupling the rotating mechanism of the drilling motor 410 to the downhole components of the rotating BHA 100 (e.g., under-reamer 412, RSS 150, LWD module 120, MWD module 130, drill bit 105).
Furthermore, turbine power is not available when pumps are off, so a battery would be used to power the D&I sensor package 477 along with logic using other parts of the system to detect when pumps are turned off. The embodiment illustrated in
The power system 408 may also include a battery 488 that utilizes the wireless power and data connection 402. The battery 488 may be used in conjunction with a modulator and turbine power system. Alternatively, the battery 488 may include the sole or primary power source for the power system 408.
In an embodiment, as illustrated in
The power and telemetry system 408 may include a stator 483, a rotor 487, and a turbine 485. Stator 483 and rotor 487 are the modulator for producing the telemetry. Stator 483 is static (non-moving) while rotor 487 rotates to create modulation for the telemetry using mudflow.
Mudflow through the power system 408 rotates these elements in order to produce power and the telemetry signals. As noted previously, the power system 408 may include a battery 488 which could be used as a substitute for the turbine 485. Alternate combinations of power generation (i.e. mechanical or electrical/chemical, etc.) for the power system 408 are included within the scope of this disclosure as understood by one of ordinary skill the art. This power and telemetry system 408 may generate negative mud pulse signals as well as positive mud pulse signals. EM telemetry pulse signals from coils (using the data coils 266, 268 of
Referring now to
The equation illustrated in table 1900 of
This lower rate of attenuation with the intrinsically high data rate of a rotary mud pulse telemetry system, enable greater bandwidth of real-time data than has been possible with existing directional practice and drill-pipe conveyed MWD systems. The viscosity and bulk modulus of the mud are strongly dependent on type of mud, temperature and pressure and will therefore be functions of total depth, vertical depth, water depth, geographical area, etc.
The equation in graph 1900 of
The positive impact of the larger diameter (such as 7.0 inch or 17.8 cm diameter) in casing drilling compared to standard drill pipe drilling (such as 5.0 inch or 12.7 cm diameter) is very apparent in the graph 2005 illustrated in
Graph 2005 shows that with a larger internal diameter of casing (see line with point 2015), telemetry rates in the range of about 12 bit/sec may be possible to depths of approximately 20,000.0 feet or 6.01 km (point 2015) as compared to a smaller drill pipe diameter of about 5.0 inches or 12.7 cm (see line with point 2010) where about a 12 bit/sec data rate is limited to approximately 13,000 feet or 3.96 km. Line 2020 defines a minimum threshold of about 1.0 psi for detecting a signal using mud pulse signaling/modulation.
Further benefits and advantages of the BHA 100 are shown with reference to graph 2105 of
There may also be an approximately four-fold increase in signal amplitude with casing drilling as compared to standard drill-pipe drilling for about a 1 Hz telemetry in mud pulse signaling. Based on the data in graph 2105, the maximum depth at which a signal may still be detected using casing drilling with 1 Hz telemetry may fall within the range of between about 40,000 to about 50,000 feet (about 12.19 km to about 15.24 km).
It should be appreciated that the above-described configurations for the casing drilling BHA 100 may be integrated with accompanying computer programs for configuring, operating, or otherwise interacting with the real-time measurement and control functionalities enabled by the corresponding BHA configurations. The computer programs may be implemented in control module(s) 101 and/or alert module(s) 110, which include logic for instructing CPU(s) in the controller 106 to execute corresponding methods.
With the system described above, power and/or communications may be efficiently passed from a tool located above the mud motor to the rotor via two coils. One coil may be annular and located in the ID of the drill collar. The other coil is attached to the rotor and is located within the first coil. The coils are high Q and resonated at the same frequency. The impedance of the power source is matched to the impedance looking toward the transmitting coil. The impedance of the load is matched to the impedance looking back toward the source.
Advantages of the inventive method and system include, but are not limited to, the second coil of the two coils being able to rotate and to move in the axial and radial directions without loss of efficiency. According to the inventive method and system, room exists for mud to flow through the two coils. Further, power may be transmitted from the tool above the motor to the bit by passing the wires through the rotor.
Various sensors of the inventive system and method may be located at the bit, powered by the tool located above the mud motor. Measurements at the bit may include, but are not limited to, resistivity, gamma-ray, borehole pressure, bit RPM, temperature, shock, vibration, weight on bit, or torque on bit.
Another advantage of the inventive method and system is that two way communications may be made through the mud motor by adding a second set of coils. Additionally, resistivity measurements at the bit may be made by using two coils as receivers, as powered by this inventive system and method.
The inventive method and system may provide for efficient power transfer. According to one aspect, power may be transmitted between two coils where the two coils do not have to be in close proximity (see equation 1 discussed above) in which k may be less than (<1) or equal to one. Another potential distinguishing aspect of the inventive method and system includes resonating the power transmitting coil with a high quality factor (see equation 3 discussed above) in which Q may be greater than (>) or equal to about 10. Another distinguishing aspect of the system and method may include resonating the power transmitting coil with series capacitance (see equation 2 listed above).
Other unique aspects of the inventive method and system may include resonating the power transmitting coil with parallel capacitance and resonating the power receiving coil with a high quality factor Q (see equation 3) in which Q is greater than (>) or equal to 10. Other unique features of the inventive method and system may include resonating the power receiving coil with series capacitance (see equation 2 discussed above) as well as resonating the power receiving coil with parallel capacitance.
Another unique feature of the inventive method and system may include resonating the transmitting coil and the receiving coil at similar frequencies (see equation 2 described above) as well as matching the impedance of the power supply to the impedance looking toward the transmitting coil (see equation 10 described above). Another distinguishing feature of the inventive method and system may include matching the impedance of the load to the impedance looking back toward the receiving coil (see equation 12 described above).
An additional distinguishing aspect of the inventive method and system may include using magnetic material to increase the coupling efficiency between the transmitting and the receiving coils. Further, the inventive method and system may include a power receiving coil that includes wire wrapped around a ferrite core (for example, see
Although a few embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the embodiments without materially departing from this disclosure. Accordingly, such modifications are intended to be included within the scope of this disclosure as defined in the following claims. In the above discussion of the casing drilling BHA 100, both LWD and RSS equipment are located below the downhole drilling motor 410. However, the RSS could run without the LWD equipment, or the LWD equipment could be run without the RSS. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures. It is the express intention of the applicant not to invoke 35 U.S.C. §112, sixth paragraph for any limitations of any of the claims herein, except for those in which the claim expressly uses the words ‘means for’ together with an associated function.
This application claims the benefit of and priority to U.S. Provisional Patent Application Ser. No. 61/704,630, entitled “Casing Drilling Bore Hole Assembly With A Wireless Power and Data Connection,” and filed on Sep. 24, 2012, U.S. Provisional Patent Application Ser. No. 61/704,805, entitled “System And Method For Wireless Power And Data Transmission In A Mud Motor,” and filed on Sep. 24, 2012, and U.S. Provisional Patent Application Ser. No. 61/704,758, entitled “Positive Displacement Motor Rotary Steerable System And Apparatus,” and filed on Sep. 24, 2012, the disclosures of which are hereby incorporated by reference in their entireties.
Number | Date | Country | |
---|---|---|---|
61704630 | Sep 2012 | US | |
61704805 | Sep 2012 | US | |
61704758 | Sep 2012 | US |