Patent Application
20240414660
The present invention is directed to a method. The method comprises determining a theoretical optimum capacitance value for an antenna frequency, performing a series of measurements at an antenna transmitting at the antenna frequency, determining an actual optimum capacitance value for the antenna frequency using the measurements, and storing the actual optimum capacitance value in a memory. Each of the series of measurements is taken with the actual capacitance of the antenna at a value between a first and second boundary capacitance value. The first boundary capacitance is less than the theoretical optimum capacitance value and the second boundary capacitance is more than the theoretical optimum capacitance value.
The invention is also directed to a system. The system comprises an antenna coil, a microprocessor, and a capacitor bank. The antenna coil is configured to transmit a signal at a frequency. The capacitor bank is in electromagnetic communication with the antenna coil and the microprocessor. The microprocessor is configured to perform iterative steps. The iterative steps are adjusting a capacitance of the capacitor bank and detecting a characteristic of the antenna and storing the characteristic in an array.
The invention is also directed to a beacon optimization system. The beacon optimization system comprises an antenna coil, a tunable capacitor bank, a power source, and a microprocessor. The antenna coil is configured to emit a locator signal. The capacitor bank is coupled to the antenna coil. The microprocessor is configured to iteratively modify the capacitance of the tunable capacitor bank to optimize the magnitude of the locator signal at a given frequency and iteratively modify the power supplied by the power source to optimize the current supplied to the antenna coil.
With reference to
Continuing with
An above-ground tracker 36, operated by a tracker operator 38, is used to detect and analyze the beacon signal 32 in order to determine the downhole position of the beacon. The beacon signal 32 includes information about the beacon as well as the downhole conditions, such as the downhole temperature and fluid pressure. In operation, the tracker operator 38 walks along the planned borepath tracking the beacon signal 32 with the tracker 36.
Beacons 40 may use an autotuning process to help maximize the amplitude of the signal these beacons transmit. The beacons 40 have bulk capacitance that is switched into a series resonant circuit with the antenna (an inductor). This bulk capacitance is intended to be close to the calculated capacitance needed to resonate at the given frequency. After this bulk capacitance has been switched into the circuit, there is a bank of smaller capacitors that can be individually switched in to help peak the tuning for this circuit. This is referred to as “autotuning.” This autotuning can be very slow and must happen each time the beacon is powered on at a given frequency. While it helps give the beacon better efficiency it may cause calibration and regulation times to be very slow. These types of beacons typically have a maximum of four different frequencies at which to emit the beacon signal 32.
It may be preferable for a beacon 40 to provide thirty-two or more different frequencies at which to emit the beacon signal 32. However, more frequencies mean that the calibration and tuning times must be reduced. The present invention uses a binary search capacitor configuration to achieve a broad tuning range that can support thirty-two frequencies. This capacitor configuration lends itself to being able to optimize the beacon to whatever downhole tool 30 or environment is being used. The capacitor configuration is shown in
The method for beacon optimization may comprise four separate methods, each of which is designed to improve the performance of the beacon. The first is a tuning optimization. The second is power optimization. Preferably, the power optimization comprises two separate optimization steps—one for normal power and one for high-power.
These processes are described below.
A user may further optimize the beacon by determining the capabilities of the beacon's battery prior to operation. A process for determining the capabilities of the beacon's battery is described below. Finally, during operation, the power supplied to the beacon may be reduced or eliminated while the beacon detects movement.
Tuning optimization is intended to maximize efficiency and signal output level for a given frequency in a given housing. Each downhole tool housing 30 has a slightly different effect on the tuning capacitance it takes to peak the signal coming out of the beacon.
With reference to
The capacitor bank 54 comprises a plurality of capacitors, given designations between Co and C16. Capacitor Co has a bulk value and is always a part of the system. Each of capacitors C1 through C16 is arranged in parallel, and each of these capacitors may be toggled by an associated switch S1 through S16 disposed in a switch control group 56. As shown, the microcontroller 52 controls the switch control group 56.
While various values may be provided, in one embodiment, the capacitors C1 through C16 have capacitance values which are arranged for binary switching. For example, a first of the capacitors may have a value x. The second of the capacitors has a value 2x, the third a value 4x, and so on, such that each discrete arrangement of the switch group 56 results in a different capacitance value provided by the capacitor bank 54. Such an arrangement provides a large range of discrete capacitance values from which to choose.
With reference to
At step 104, a maximum and minimum test capacitance value are determined. In one embodiment, the minimum test capacitance is 10% less than the theoretical optimum capacitance value. Likewise, the maximum test capacitance is 10% more than the theoretical optimum capacitance value. The range may be larger or smaller depending upon the application.
At step 106, the capacitor bank 54 is set to one of the values between the maximum and minimum test value. This may be, but does not have to be, the maximum or minimum value. At step 108, the beacon is energized with the antenna 50 transmitting at the transmission frequency. At 110, a characteristic of the system is recorded and stored in an array, and associated with the particular arrangement of the capacitor bank 54.
The characteristic used at 110 may be feedback voltage, or the current draw from the battery. Other characteristics may be utilized. In any case, the characteristic is indicative of the signal magnitude from the antenna 52, and is stored in a storage.
At 112, the system checks to see if all applicable capacitance values between the maximum and minimum test values have been measured. If no, the capacitor bank 54 is tuned to the next value at 114 and the measurement and storage step at 110 is repeated. It may be preferred to start at the minimum test value and increase the capacitance, stepwise, until the maximum test value is reached, though other methods of testing each capacitor arrangement in the range may be used.
If all available capacitance values in the range have been measured, the system proceeds to step 116. At step 116, the optimum characteristic value is determined, and an actual optimum capacitance value associated with that characteristic value is selected. At step 118, the capacitor bank 54 configuration associated with the actual optimum capacitance value is stored, and associated with the frequency f selected. The method ends at 120.
The method of
The method shown in
After the test range is swept, the optimum characteristic value is determined at step 116. For example, this may be the maximum feedback voltage value. The actual optimum capacitance value associated with that characteristic is then stored in a storage at 118. The beacon 40 now has a stored optimum capacitance value for 29 kHz.
This procedure is repeated for each pre-set frequency value, and the optimum capacitance stored. Thus, when the beacon 40 is later set for use at any of its pre-set frequencies, the capacitor bank 54 may be automatically set to the configuration associated with the optimum capacitance value.
After tuning optimization has been completed, power optimization begins using the newly established tuning values. The method of optimizing power levels is disclosed in
Power optimization sets the power draw consumed by the system at a given power level. This benefits the user by helping provide the specified battery life over all the frequencies and power levels. Power optimization is achieved by ramping up the output signal while monitoring the power pulled from the battery (current*voltage).
The method starts at step 200. A table of acceptable power consumption rates is referenced at 202 to determine a starting power level. The beacon 40 is tuned to the optimum capacitance for the chosen frequency at 204. The beacon is then driven by a digital to analog converter to the starting power level at 206.
Battery current and voltage are then measured at 208 to determine an actual measured power level. If the measured power is greater than or equal to the target power level at 210, the value of the digital to analog converter is set and stored in a storage at 212. If the measured power is less than the target power at 210, the value of the digital to analog converter is increased at 214 and step 208 is repeated. The method ends for a discrete target power level and frequency at 216.
This method may occur for multiple power levels. For example, the beacon may provide a normal and high-power level.
In operation, the user can select if they want to run the beacon optimization or use a default (non-optimized) set of tuning and feedback values. Once the beacon optimization and power optimization are complete, the values stored may be re-used until calibration is required.
Traditionally, a locating beacon 40 is always on, sending the beacon signal 32 to the tracker 36. However, in borepath planning and mapping techniques occur at regular intervals, not continuously. The location of the downhole tool is typically only recorded when the beacon is stationary, such as when an additional pipe segment 28 is being added to the drill string 14. Thus, any power consumed by the beacon 40 while the downhole tool 30 and drill bit 24 are in motion is wasted.
In one embodiment, the beacon signal 32 is shut down, or placed into a lower power state, when a motion sensor 60 disposed in the downhole tool 30 indicates that the beacon 40 is not stationary. When the beacon becomes stationary, the beacon signal 32 renews and data is sent to the tracker.
Sensors that are capable of detecting motion are low power, and accuracy is not critical in such a motion sensor. Therefore, the power draw from such sensors is negligible. This method will therefore increase battery life in the beacon 40 without sacrificing depth performance or the strength of the beacon signal 32.
In one embodiment, the mode in which the beacon 40 is set may be configured via a Bluetooth command. For example, an operator may direct the beacon 40 to operate in a mode in which it is always broadcasting the beacon signal, or, optionally, to operate in the mode described above, where the beacon signal 32 is only broadcast when the beacon 40 is stationary.
Alternatively, the operator may selectively choose whether the beacon signal 32 is being broadcast, such that the beacon signal 32 is only being broadcast when tracking operations at the surface are active.
As the capability of beacons, such as beacon 40, continue to expand, higher power density batteries are used. Operators, however, will continue to use whatever batteries are available. As a result, it is advantageous for a beacon 40 to distinguish between different types of batteries so that the beacon 40 can be configured to operate within the constraints of the particular battery that is being used.
A method for battery chemistry detection is shown in
At 310, the battery impedance can be approximated by taking the difference between the two load voltages and dividing by the difference between the two load currents. The difference between impedances measured using light load and heavy load is a good approximation of battery source impedance. At 312, the approximate impedance may be compared to the initial unloaded voltage to determine the battery chemistry. A table may show the source impedances vs. unloaded voltages.
Once the battery chemistry is known, assumptions about battery life and battery capability may be made at 314. For example, power consumption and rated battery life may be used to give a user a battery hour life expectancy instead of just a percentage based on battery voltage. A user can also use different settings in the beacon to limit power levels or frequencies that can be used with a given battery. This method also helps overcome Lithium Thionyl Chloride cell passivation. The method ends at 316.
While the above processes are described with reference to a horizontal
5 directional drilling system, the processes may also be used in other operations or industries where beacons are used.
Changes may be made in the construction, operation and arrangement of the various parts, elements, steps, and procedures described herein without departing from the spirit and scope of the invention as described in the following claims.
| Number | Date | Country | |
|---|---|---|---|
| 63117133 | Nov 2020 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 17531901 | Nov 2021 | US |
| Child | 18807381 | US |
