JP6902484B2 - Resource exploration system and resource exploration method - Google Patents

Description

The present invention relates to a self-diagnosis method of a sensor used for seismic wave exploration of oil, gas, etc. existing underground.

In order to investigate the distribution of resources such as oil and gas existing underground, as a method of grasping the underground geological structure, elastic waves are captured using velocity sensors and acceleration sensors, and the geological structure is analyzed by analyzing the data. It is widely practiced to grasp. Large reservoirs (oil or gas reservoirs) that are easy to mine in oil and gas have already been discovered or developed and will require deeper and more complex geological exploration in the future. In order to realize them, it is important to increase the sensitivity of the sensor and high-density exploration, and in addition, the market demands low-cost operation.

One of the methods widely used in resource exploration is a method called geophysical exploration or reflection seismic exploration. In principle, elastic waves generated by artificial seismic sources (dynamite, oscillating wheels that vibrate the ground, etc.) are reflected at the interface of the stratum, such as the oil layer, gas layer, water, and rock layer, and are reflected on the surface of the earth. The returning reflected wave is detected as acceleration by a large number of sensors installed on the ground surface or in a well, and the reservoir image is constructed from the acceleration data.

Further, as a method of collecting data from a sensor, an example of a cable type system is disclosed in Patent Document 1. In this system, the sensor is always connected to the central control device, and the signal from the vibration sensor is collected each time during exploration. In this case, the control device acquires a signal from the vibration sensor, and it becomes easy to determine the failure status of the sensor. Therefore, it is not necessary to have a special self-diagnosis mode other than the process of collecting vibration.

There are currently two movements in the resource exploration system. One is the change of the device, and unlike the conventional coil type Geophone, a high-sensitivity sensor using MEMS (Micro Electro Mechanical Systems) technology including a semiconductor circuit and a mechanism is being put into practical use.

In addition, in order to increase the image resolution, the number of sensor terminals used in one system will increase from the current mainstream of tens of thousands to one million in the future. If one million sensors are connected by wire such as a cable or an optical fiber in this way, the cable length increases, making it difficult to install the cable and collect data. For this reason, blind nodal type terminals have appeared. In the blind nodal type terminal, acceleration data is stored in the memory inside the terminal during exploration, and when the exploration is completed and the terminal is returned to the observation vehicle, the data is collectively collected.

U.S. Patent Application Publication No. 2007/0258319 Japanese Unexamined Patent Publication No. 63-024184

Sensors manufactured by MEMS technology have the advantage of being small and capable of mass production, but because the manufacturing process is not mature enough, there are individual differences in performance for each element produced due to the process. May occur.

In addition, since the places where resources are buried are widely distributed in harsh environments such as deserts, jungles and tundra, individual deterioration is expected depending on the usage history of the device. Specifically, in addition to aging deterioration, the temperature, humidity and their change cycles at the exploration site, as well as vibration and storage conditions caused by transportation, cause damage or deterioration of the MEMS mechanical mechanism, deformation of chips and substrates. , The degree of vacuum of the package may decrease.

However, in seismic wave exploration using a blind nodal type terminal, it may take about one month for a large number of sensor terminals to be installed to measure vibration and to recover the sensors again. Meanwhile, the sensor terminal continues to receive and accumulate acceleration data.

Therefore, if the sensor terminal fails during measurement, the failure is found only after collection, and acceleration data for the period after the failure cannot be acquired. Therefore, if a failure occurs in a large number of sensor terminals, a large number of defects will occur in the acceleration data, and the accuracy of the image of the underground structure reproduced using the defects will be significantly reduced.

Patent Document 2 discloses an example in which a self-diagnosis of a sensor terminal is performed in order to discover a failure that occurs after the sensor terminal is installed in the field. In the example of Patent Document 2, after the sensor terminal is installed, the self-diagnosis monitoring device and the geophone are wirelessly connected, a test command for executing the self-test operation is transmitted, and the self-diagnosis monitoring device collects the diagnosis result. At that time, after the self-diagnosis of all the sensor terminals is completed, seismic waves are generated and vibrations are received.

In this method, seismic wave exploration cannot be performed until all the sensor terminals perform self-diagnosis and transmit the result to the monitoring device. Therefore, it becomes necessary to interrupt the seismic wave exploration every time the self-diagnosis is performed, and there is a problem that the period for exploring a certain area increases. Prolonged survey periods lead to increased exploration costs, including the costs of workers and equipment required for the survey.

Therefore, the present invention has been made in view of the above problems, and it is a seismic wave exploration system using a blind nodal type sensor terminal to detect that the sensor terminal is operating normally during the exploration period. The purpose.

The present invention is a resource exploration system in which a plurality of sensor terminals are arranged in a search target area, and the plurality of sensor terminals measure reflected waves of vibration oscillated from a vibration source. The sensor terminals are processors. A memory, a sensor, a signal processing unit that converts a value detected by the sensor into data and stores the value in the memory, and a communication unit. run the self-diagnosis to detect the presence or absence of abnormality, it sends a self-diagnosis result information, the plurality of sensor node, after starting the measurement of the reflected wave, at least one sensor terminal of the signal processing unit processing temporarily interrupted to return to the measurement of the reflected wave to transmit the self-diagnosis result from the communication unit to perform a self-diagnosis for diagnosing the presence or absence of the own sensor abnormality after the self-diagnosis is completed, The sensor includes an acceleration sensor to which MEMS technology is applied, the signal processing unit converts the acceleration detected by the acceleration sensor into acceleration data and stores it in the memory, and the acceleration sensor applies the applied acceleration. It has a movable portion that is displaced accordingly, a first electrode is provided on the movable portion, a second electrode is provided at a position facing the movable portion, and the electrostatic capacitances of the first electrode and the second electrode are provided. In the self-diagnosis, the processor measures a Q value indicating the strength of resonance of the movable part, and if the measurement result of the Q value is less than a predetermined threshold value, the sensor terminal is used. The self-diagnosis result is determined to be faulty, the self-diagnosis result is transmitted, and the optimum value of the voltage applied to the DC servo capacitance to cancel the gravitational acceleration applied to the moving part when the sensor terminal is activated is detected. Then, in the self-diagnosis, by applying a voltage pulse to the DC servo capacitance, resonance is generated in the moving portion to measure the Q value, and before returning from the self-diagnosis to the vibration measurement, the self-diagnosis is performed. The optimum value of the voltage applied to the DC servo capacitance for canceling the gravitational acceleration applied to the moving part is detected again and the calibration is performed .

According to the present invention, in a system using a large number of blind nodal type sensor terminals equipped with sensors capable of mass production at a low price such as a MEMS sensor, it is being investigated that the sensor terminals are operating normally. The sensor can be calibrated if necessary. Therefore, the accuracy and reliability of the measured acceleration data can be improved. Further, since it is not necessary to provide a special time for all the sensor terminals to perform only self-diagnosis, the time required for exploration can be shortened and the exploration cost can be reduced. In addition, although the performance is excellent, it becomes possible to easily use a MEMS sensor that has just been put into practical use.

It is a figure which shows the Example of this invention and shows an example of the resource exploration system. It is a figure which shows the Example of this invention, and shows the work flow of resource exploration, and the example of the storage place of acceleration data. It is a block diagram which shows the Example of this invention and shows an example of a sensor terminal. It is a block diagram which shows the Example of this invention and shows an example of the management apparatus. It is a figure which shows Example 1 of this invention and shows an example of the laying layout of a sensor terminal. It is a figure which shows the Example of this invention and shows the 1st example of the timing of vibration measurement and self-diagnosis processing. It is sectional drawing of the MEMS acceleration element which shows the Example of this invention. An example of the present invention is shown, which is a cross-sectional view taken along the line AA'of a MEMS chip. An embodiment of the present invention is shown, and it is a top view of the MASS layer. It is a graph which shows the Example of this invention, shows an example of self-diagnosis processing, and shows the relationship between voltage, capacitance and time. It is a block diagram which shows the Example of this invention and shows the example of the electrical connection of a MEMS acceleration element and an acceleration signal processing part. It is a figure which shows the Example of this invention and shows the 2nd example of the laying layout of a sensor terminal. It is a figure which shows the Example of this invention and shows the 2nd example of the timing of vibration measurement and self-diagnosis processing. It is a figure which shows the Example of this invention and shows the 3rd example of the timing of vibration measurement of a sensor terminal, self-diagnosis processing. It is a figure which shows the Example of this invention and shows the 1st example of the timing of vibration measurement of a sensor terminal, self-diagnosis processing, and transmission of a diagnosis result. It is a figure which shows the Example of this invention and shows the 2nd example of the vibration measurement of a sensor terminal, self-diagnosis processing, and the timing of transmission of a diagnosis result. It is a figure which shows the Example of this invention and shows an example of the screen which receives and displays the self-diagnosis result. It is a figure which shows the Example of this invention and shows the example of switching from self-diagnosis processing to vibration measurement processing. It is a figure which shows the Example of this invention and shows the example which performed the calibration after the self-diagnosis process.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1A is a diagram showing an example of a resource exploration system. Although it is shown in a simplified configuration for explaining the points of the present invention, the sensor terminals and the vibration points are not necessarily arranged in an orderly manner as shown in the figure due to various factors in the field.

The earthquake simulation vehicle 100 constitutes one group consisting of one or a plurality of vehicles, becomes an earthquake simulation vehicle group 101a, moves to the earthquake simulation point 102, and causes vibration. The earthquake simulation vehicle group 101a may be composed of, for example, four earthquake simulation vehicles 100. In FIG. 1A, only one vibration point 102 is shown as the vibration point, but all the intersections of the grids (broken lines in the figure) shown in FIG. 1 may be the vibration points. Therefore, the earthquake simulation vehicle group 101a oscillates at the oscillating points, which are the intersections of the grids, while moving along the movement path 104a in a substantially straight line.

When the shaking vehicle group 101a moves to the shaking point 102 and shakes, it makes a U-turn and shakes while moving along the movement path 104b. In this way, by repeating the movement in a substantially straight line and the U-turn, the earthquake simulation vehicle group 101a is oscillated at a preset oscillating point, for example, all the intersections of the grid shown in FIG. 1A. The vibration points are set at predetermined fixed intervals such as 50 m. The position of the vibration point is specified by, for example, a GPS (Global Positioning System) signal from the satellite 105.

For example, 100,000 vibration points are set according to the area of the exploration target area. Since there are many vibration points, a plurality of vibration vehicle groups 101 including the vibration vehicle group 101a (when the vibration vehicle group 101a is not specified and the simulation vehicle group in FIG. 1A is shown, it is referred to as the vibration vehicle group 101. It is the same by dividing the exploration target area into multiple areas using (the same applies to the description of other codes), shifting the vibration timing so that there is no effect, and adding a code to the vibration waveform. You may explore at the time.

Further, the earthquake simulation vehicle group 101 may be a plurality of rows such as two rows. Depending on the area to be explored and the density of the vibration points, it may be preferable that the group 101 of the vibration vehicle group 101 has two rows of two vehicles rather than one row of four vehicles. Further, the earthquake simulation vehicle group 101 may have, for example, one earthquake simulation vehicle 100. Regardless of the configuration of the earthquake simulation vehicle group 101, the vibration energy of the earthquake simulation vehicle group 101 is measured and recorded in advance. The earthquake simulation vehicle group 101a repeats vibration and movement, and moves to the position of the earthquake simulation vehicle group 101b.

The vibration caused by the vibration of the oscillating vehicle group 101b is reflected at the interface between the stratum such as a rock layer and the reservoir 110 in which oil or gas is buried, becomes a reflected wave 112a, is detected by the sensor terminal 103, and accelerates. It is accumulated as waveform data. Although it is a vibration that is not necessary for exploration, there is also a surface wave 111a that propagates on the ground surface from the earthquake simulation vehicle group 101b to the sensor terminal 103.

The sensor terminal 103 detects the vibrations of the surface wave 111a and the reflected wave 112a as acceleration. In a known or well-known example, since the distance from the earthquake simulation vehicle group 101b to the sensor terminal 103 is shorter than the distance from the earthquake simulation vehicle group 101b to the sensor terminal 103 via the reservoir 110, the acceleration 111b due to the vibration of the surface wave 111a Is detected earlier than the acceleration 112b due to the vibration of the reflected wave 112a from the time of vibration, and has a larger value. Therefore, it is easy to extract only the reflected wave indicating underground information from the received signal.

FIG. 1B shows the relationship between the exploration work flow and the acceleration data storage device. In this example, the processing of the blind nodal type terminal is shown, and the acceleration data of the reflected wave detected during the exploration work is stored in the memory in the sensor terminal 103. When the number of sensor terminals increases to the level of 100,000 and the measurement accuracy of the sensor terminals 103 increases, the amount of data acquired by one sensor terminal 103 increases, so that the total amount of data becomes enormous. Therefore, it is difficult to send the data of all the sensor terminals 103 to the observation vehicle 106 during the exploration work due to the limitation of the wired or wireless communication capacity, so it is necessary to store the acceleration data in the sensor terminal 103.

As shown in FIG. 1A, a plurality of sensor terminals 103 are arranged in the exploration target area. Similar to the vibration point, for example, 100,000 sensor terminals 103 are arranged according to the area of the exploration target area and the like. The sensor terminal 103 may be arranged in an area that overlaps with the movement path 104 of the earthquake simulation vehicle group 101, or the sensor terminal 103 may be arranged in an area that does not overlap with the movement path 104 of the earthquake simulation vehicle group 101. The exploration target area may be a desert or an urban area.

FIG. 1B is a diagram showing a work flow of resource exploration and an example of a storage location of acceleration data. The sensor terminal 103 is arranged before the earthquake simulation vehicle group 101 starts the first vibration (T0), the earthquake simulation vehicle group 101 continues to be arranged during movement or vibration, and the earthquake simulation vehicle group 101 continues to be arranged. It is collected when the final vibration is completed (T2). Alternatively, in order to expand the exploration area, vibration is generated by the earthquake simulation vehicle group 101 and measurement is performed by the sensor terminal 103 while sequentially replacing the sensor terminals 103 (T1). Therefore, the sensor terminal 103 may be placed in a harsh environment for a long time.

As shown in FIG. 1B, when the sensor terminal 103 is collected by the observation vehicle 106, the acceleration data in the memory is transferred to the storage device of the management device installed in the observation vehicle 106 (T3), and then analyzed. Will be done.

FIG. 2A is a block diagram showing an example of the configuration of the sensor terminal 103. The MEMS (Micro Electro Mechanical System) acceleration element 201 is an acceleration element formed by MEMS technology, and detects vibration applied to a sensor terminal 103 such as a surface wave 111a or a reflected wave 112a as an acceleration and converts it into an electric signal. The MEMS technology is a technology for mounting a mechanical element (sensor or actuator) and an electronic circuit on one substrate (printed circuit board or the like).

Although the MEMS acceleration element 201 has high sensitivity, it has a fine structure and the hard material vibrates mechanically, so that it is not only subjected to strong impacts such as external influences, but also in sudden temperature cycles and high and low temperatures. There is a possibility of deterioration or damage due to the operation of.

The MEMS acceleration element 201 has a fixed portion to which external vibration is transmitted and a movable portion connected via an elastic body, and captures acceleration from, for example, a change in capacitance value between the fixed portion and the movable portion due to external vibration.

Due to these factors and problems such as the material characteristics and packaging of the MEMS acceleration element 201, the MEMS acceleration element 201 may have a possibility that, for example, the degree of vacuum between the fixed portion and the movable portion decreases, and the elastic identification of the elastic body changes. There is. Then, there is a possibility of deterioration such as an increase in the minimum width of the detectable vibration, an increased minimum width exceeding a predetermined threshold value, or damage in which the vibration cannot be detected at all.

The MEMS acceleration element 201 is not limited to the capacitance detection type acceleration sensor, and may have another structure, but factors added from the outside may be different.

The acceleration signal processing unit 202 amplifies the electric signal of the acceleration converted by the MEMS acceleration element 201, converts the amplified analog electric signal into the acceleration data of the digital electric signal, and digitally according to the detection characteristics of the MEMS acceleration element 201. Correct the electrical signal. That is, the MEMS acceleration element 201 and the acceleration signal processing unit 202 are combined to form an acceleration sensor.

Further, the acceleration signal processing unit 202 may be an ASIC (Application Specific Integrated Circuit). The acceleration data converted by the acceleration signal processing unit 202 is stored in the memory 205.

The external I / F (Interface) 203 is an interface for communicating with the outside of the sensor terminal 103, and may be a wireless communication interface, a wired communication interface, or a wireless communication and a wired communication. It may be both interfaces. The external I / F 203 transmits the self-diagnosis result information described later to the management device 10 of the observation vehicle 106 during the exploration work.

When the sensor terminal 103 is collected by the observation vehicle 106, the acceleration data stored in the memory 205 is installed in the observation vehicle and transferred to the storage device of the observation vehicle. Further, the external I / F 203 may transmit the value detected by the environment sensor 207, may transmit the information input from the processor 204, and may output the received information to the processor 204. In FIG. 2A, the environment sensor 207 is mounted on the sensor terminal 103, but equivalent data may be acquired in other mounting modes.

The processor 204 controls each part in the sensor terminal 103 according to a program stored in the non-volatile storage unit (not shown) in advance. The processor 204 may transfer acceleration data from the acceleration signal processing unit 202 to the external I / F 203, transfer values from the environment sensor 207 to the external I / F 203, and memory for these transfers. The value may be stored in 205.

Further, when it is necessary to set predetermined parameters to the acceleration signal processing unit 202, the external I / F 203, the GPS receiving unit 206, and the environment sensor 207, the processor 204 may set the parameters according to the program.

Processor 204 may include one or more timers. The timer may count the time from a preset time. The preset time may be the time when the sensor terminal 103 including the processor 204 is manufactured, the time when the MEMS acceleration element 201 is manufactured, or a specific standard time. The counting period may be counted without stopping, may be counted only during the energization period, or may be started and stopped based on preset conditions.

The memory 205 may store a program for the processor 204, or may store data necessary for the processor 204 to execute the program. The memory 205 may store the values output by the acceleration signal processing unit 202, the GPS receiving unit 206, and the environment sensor 207.

Further, the memory 205 may store the sensor ID as information for identifying the MEMS acceleration element 201. Further, the memory 205 may store the frequency characteristics of the sensitivity of the MEMS acceleration element 201 as a mathematical formula, a table, a model, or the like. Alternatively, as a storage location of information, the sensor ID or the like is linked to a local database or cloud of a manufacturer of the MEMS acceleration element 201 or the sensor terminal 103, a company that owns the sensor terminal 103, a company that performs analysis and interpretation, an oil company, or the like. However, the data may be retained.

When the sensor terminal 103 includes a plurality of MEMS acceleration elements 201, the number of stored sensor IDs may be a plurality. The sensor ID may be information for identifying the sensor terminal 103, not information for identifying the MEMS acceleration element 201.

Further, the processor 204 is a so-called microcomputer, and the processor 204 has a built-in memory, and programs and data stored in the memory 205 may be stored in the memory built in the processor 204.

The GPS receiving unit 206 receives the GPS signal and outputs the position information of the sensor terminal 103. The processor 204 may store the position information output by the GPS receiving unit 206 in the memory 205 together with the values output by the acceleration signal processing unit 202 and the environment sensor 207, or may transmit the position information by the external I / F 203. ..

If the position information of the sensor terminal 103 is specified by another device when the sensor terminal 103 is arranged, the GPS receiving unit 206 may not be provided. Further, the GPS receiving unit 206 may be configured to receive a GPS signal and synchronize the time.

The environment sensor 207 includes, for example, a temperature sensor that detects the temperature of the MEMS acceleration element 201 or the temperature outside the sensor terminal 103. The environment sensor 207 may include a humidity sensor and may include an acceleration sensor in addition to the MEMS acceleration element 201. Another accelerometer may be an accelerometer manufactured at the same time or different time as the MEMS accelerometer 201, or in the same lot or a different lot, or an accelerometer having a structure different from that of the MEMS accelerometer 201. There may be.

The processor 204 compares the value output by the acceleration signal processing unit 202 or the environment sensor 207 with a preset threshold value, and if it is determined that the output value exceeds the threshold value, the acceleration signal processing unit 202 and the environment sensor 207 The value output from the GPS receiving unit 206 may be stored in the memory 205 together with the counted value of the timer, or may be transmitted from the external I / F 203.

Further, when the timer count reaches the value of the preset interval, the processor 204 stores the value output from the timer in the memory 205 together with the counted value of the timer, or transmits the value from the external I / F 203. You may. The battery 208 supplies power to each circuit in the sensor terminal.

FIG. 2B is a block diagram showing an example of the management device 10 arranged in the observation vehicle 106. The management device 10 manages the sensor terminal 103 arranged in the exploration target area.

The management device 10 is a computer including a processor 11, a memory 20, a storage device 30, an external I / F 12, an input device 13, and a display device 14.

The external I / F 12 is an interface that communicates with the outside of the management device 10, and may be an interface for wireless communication, an interface for wired communication, or an interface for both wireless communication and wired communication. There may be. The external I / F 12 receives the self-diagnosis result information from the sensor terminal 103 during the exploration work. The external I / F 12 may receive position information (GPS information) and environmental information (measurement data of the environmental sensor 207) from the sensor terminal 103.

The input device 13 is composed of a keyboard, a mouse, or a touch panel, and accepts operations by the user of the management device 10. The display device 14 is composed of a display or the like, and displays the processing result of the processor 11.

The sensor terminal management unit 21 is loaded into the memory 20 as a program and executed by the processor 11. As will be described later, the sensor terminal management unit 21 manages the operating state of each sensor terminal 103 based on the self-diagnosis result information received by the sensor terminal 103. The sensor terminal management unit 21 stores the received self-diagnosis result information in the storage device 30, and updates the sensor operation data 31 indicating the operation state of each sensor terminal 103.

The processor 11 operates as a functional unit that provides a predetermined function by processing according to the program of each functional unit. For example, the processor 11 functions as the sensor terminal management unit 21 by processing according to the sensor terminal management program. The same applies to other programs. Further, the processor 11 also operates as a functional unit that provides each function of a plurality of processes executed by each program. A computer and a computer system are devices and systems including these functional parts.

FIG. 3A is a diagram showing an example of an image in which the sensor terminal 103 is laid in the exploration field SF. In exploration, the exploration service company designs an exploration plan according to the sensor terminal 103 and the earthquake simulation vehicle 100 owned by the exploration area and time pointed out by the client such as an oil company. That is, it is a specification of when and in what layout the sensor terminal 103 is laid and at what vibration point 102 the sensor terminal 103 is laid. At this time, when the number of sensor terminals 103 is insufficient, such as in a large-scale exploration, it is widely practiced to cover a predetermined exploration area by sequentially replacing the sensor terminals 103.

In the form called blind nodal of the present invention, the sensor terminal 103 itself has a battery 208 and a memory 205, and acceleration data is stored during the exploration period, and the data is stored in the management device 10 when the sensor terminal 103 is collected. Transfer to. The blind nodal form is used in a location where cable connection is difficult, for example, when there is a river, or when the number of sensor terminals 103 is huge and the handling of the cable becomes complicated.

FIG. 3B is a diagram showing a first example of timing of vibration measurement and self-diagnosis processing of the sensor terminal 103. The earthquake simulation vehicle group 101 moves on the movement path 104, stops sequentially from each vibration point # (1,1) to # (M, N) near the sensor terminal 103, and performs vibration (S in the figure). , The sensor terminal 103 arranged at these points measures the acceleration of the reflected wave 112a (Receive).

In this embodiment, when the vibration is performed at the point # (1,1) at the time t1, the self-diagnosis process (QC in the figure) is performed by the sensor terminal 103 located at the point # (1,1). Subsequently, at time t2, when the earthquake simulation vehicle 100 excites at points # (1, 2), the sensor terminal 103 located at # (1, 2) performs self-diagnosis processing. This is repeated until the point # (M, N).

In this way, during the measurement of vibration, one sensor terminal 103 temporarily interrupts the measurement and sequentially performs the self-diagnosis process, so that a large number of blind nodal type sensor terminals 103 operate normally. The presence can be detected during exploration, and the reliability of the measured data can be maintained. Further, since all the sensor terminals 103 do not have time to perform only the self-diagnosis process, the time required for exploration can be shortened and the exploration cost can be reduced.

In the first example, the time when the sensor terminal 103 starts the self-diagnosis process is set to be staggered, so that the period of the self-diagnosis process of the sensor terminal 103 is the period of the self-diagnosis process of the other sensor terminal 103. Prevents duplication with, but is not limited to this. For example, the management device 10 may instruct the sensor terminal 103 to start the self-diagnosis process, and can sequentially shift the start time of the self-diagnosis process so that the periods of the self-diagnosis process do not overlap. ..

4A to 4D are a structural diagram of the MEMS acceleration element 201 and a diagram showing an example of self-diagnosis processing.

FIG. 4A shows a cross-sectional view of the MEMS acceleration element 201. The MEMS chip 401, which is formed by laminating a material such as Si inside a package made of ceramic or plastic, is adhered with silver paste or the like. Although not shown in the figure, the electrode terminals on the MEMS chip 401 are electrically connected to the electrode terminals of the package by wire bonding or unwiring in the package. The MEMS acceleration element 201 may be equipped with an acceleration signal processing unit 202.

FIG. 4B shows a cross-sectional view of the MEMS chip 401. This figure is a cross-sectional view taken along the line AA'shown in FIG. 4C. In this embodiment, an example composed of a three-layer Si chip of a base layer (BASE), a weight layer (MASS), and a cap layer (CAP) is shown. The movable weight formed in the MASS layer is conductive and forms a capacitance with the counter electrode formed in the CAP layer.

FIG. 4C shows a plan view of the MASS layer in the MEMS chip 401. In the MASS layer, the movable weight 402 is connected to the anchor portion 404 by releasing the spring 403. The anchor portion 404 is joined and fixed to the base layer and the cap layer. The illustration of the joint is omitted.

The movable weight 402 and the spring 403 are not joined to other layers. In the cross-sectional view of FIG. 4B, when acceleration is applied from the outside in the direction from top to bottom, the right side portion of the weight layer (MASS layer) in the figure is heavier than the left side portion with respect to the spring 403, so that the right side is It is displaced downwards and the left side is displaced upwards.

In the figure, the patterns of the six fixed electrodes arranged on the cap layer facing the MASS layer are shown by dotted lines. Of the paired acceleration detection capacities, the left and right capacities are CSL and CSR, respectively. Similarly, the DC servo capacitances CDR and CDR and the AC servo capacitances CAL and CAR are formed.

When the above acceleration is applied, the capacitance CSL, CDR, CAL increase and the capacitance CSR, CDR, CAR decrease. Acceleration is measured by measuring these capacitance changes during vibration measurement.

FIG. 4D shows an example of self-diagnosis processing, and is a graph showing the relationship between voltage, capacitance and time. The voltage VDC applied to the DC servo capacitance CDR terminal (DR) is shown on the vertical axis. A voltage VL is applied to the movable electrode (MASS layer) side, and a voltage VH is applied to the DC servo capacitance CDR terminal (DR) (however, VH> VL).

Then, a voltage of VH-VL is applied between the movable electrode and the CDR terminal, and both are attracted by an electrostatic force to reduce the distance between the movable electrode and the fixed electrode. Therefore, the acceleration detection capacitance CSR increases from C0 in the steady state to C1.

Here, when the voltage VDC is instantly returned to VL, the electrostatic force applied to the weight (movable electrode) becomes zero, so that the movable weight (MASS layer) moves away from the fixed electrode (CAP layer) and at the resonance frequency f0. Start vibrating. That is, the movable weight (MASS layer) is resonated by applying a voltage pulse that becomes a voltage VL to the DC servo capacitance CDR terminal (DR).

The capacitance change at this time is shown at the bottom of FIG. 4D. Assuming that the time until the capacitance change ΔC becomes 1 / e is τ, the Q value indicating the resonance strength is calculated by Q = π ・ τ ・ f0. Will be the value to be.

The larger the Q value, the smaller the self-noise of the sensor, and the higher the performance as a sensor. In the MEMS sensor used for the resource exploration of this embodiment, the pressure of the gas around the movable layer is often lowered in order to lower the resistance between the movable weight (MASS layer) and the gas around it and increase the Q value. ..

Therefore, a process of evacuating the inside of the cavity is used during the production of the MEMS chip 401 or the production of the package. However, the degree of vacuum may decrease due to deterioration when the MEMS sensor is used in a harsh environment such as high temperature and high humidity for a long period of time, and the Q value may decrease. By measuring the Q value with this method and comparing the magnitude with the specified value, it is possible to diagnose the failure of the MEMS acceleration element 201. For example, if the measured Q value is less than the specified value (threshold value), the processor 204 can determine that the sensor terminal 103 has a failure.

FIG. 5 shows a block diagram of the MEMS acceleration element 201 and the acceleration signal processing unit 202 that controls the MEMS acceleration element 201.

In the MEMS acceleration element 201, the movable electrode (MASS layer) is electrically divided into an output electrode 1 (O1) and an output electrode 2 (O2), and six capacitances are provided between these and the fixed electrode (CAP layer). Capacitance (CSL to CAR) is formed.

The left and right acceleration detection capacitances CSL and CSR are formed between the input terminals SL, SR and O1. The DC servo capacitances CDR and CDR are formed between the input terminals DL, DR and O2. The AC servo capacitances CAL and CAR are also formed between the input terminals AL, AR and O2. The output terminal O1 is connected to the input terminal of the operational amplifier in the ASIC, and the output terminal O2 is connected to the DC bias voltage VB3.

Complementary modulation clocks are input to the input terminals SL and SR. A control voltage from the DC servo control unit is applied to the input terminals DL and DR. The output voltage of the 1-bit D / A converter is applied to the input terminals AL and AR.

In the acceleration signal processing unit 202 composed of the ASIC, the amount of charge proportional to the acceleration input from the MEMS acceleration element 201 is amplified by the charge amplifier formed by the operational amplifier, the feedback resistance RF, and the capacitance CF at the first stage of the input. .. This is further processed by an amplifier and an analog filter, and then digitized by an A / D converter. This is input to the demodulator, processed by the AC servo control circuit, density-modulated by the 1-bit quantizer and the 1-bit D / A converter, and applied to the input terminals AL and AR.

When this feedback voltage is applied to the DC servo capacitance, a force that cancels the input acceleration is generated in the movable electrode (MASS layer), and the movable electrode (MASS layer) is feedback-controlled so as to operate while being substantially stationary. Further, the output of the 1-bit quantizer is input to the digital filter and output as acceleration data.

FIG. 6A is a diagram showing a second example of an image in which the sensor terminal 103 is laid in the exploration field. Here, the exploration field is divided into two regions, SF1 and SF2. FIG. 6B is a diagram showing a second example of the timing of the vibration measurement of the sensor terminal 103 and the self-diagnosis process.

The earthquake simulation vehicle group 101 first moves in the movement path 104 in the exploration field SF1, stops sequentially from each vibration point # (1, 1) to # (M, N) near the sensor terminal 103, and excites. (S in the figure) is performed. After that, in the exploration field SF2, the movement path 104 is similarly moved, and the vibrations (S in the figure) are sequentially stopped from the vibration points # (1, 1) to # (M, N) near the terminal. Do. The sensor terminals 103 arranged in the exploration fields SF1 and SF2 measure the acceleration of the reflected wave (Receive).

In this second example, at time t1, when the vibration is performed at the points # (1, 1) in the exploration field SF1, the sensor terminals arranged at the points # (1, 1) in the exploration fields SF1 and SF2. The self-diagnosis process (QC) is performed at 103. Subsequently, at time t2, when the earthquake simulation vehicle excites at the point # (1, 2) in SF1, self-diagnosis is performed by the sensor terminal 103 arranged at # (1, 2) in SF1 and SF2. Perform processing. This is repeated until the SF1 point # (M, N).

Further, at time tMN + 1, when the earthquake simulation vehicle group 101 excites at the points # (1, 1) in the exploration field SF2, they are arranged at the points # (1, 1) in the exploration fields SF1 and SF2. The sensor terminal 103 performs a self-diagnosis process (QC). Subsequently, at time tMN + 2, when the earthquake simulation vehicle group 101 excites at the point # (1, 2) in the exploration field SF2, it is arranged at the # (1, 2) in the exploration fields SF1 and SF2. The sensor terminal 103 performs a self-diagnosis process. This is repeated until the point # (M, N) of the exploration field SF2.

In this way, during the vibration measurement, the sensor terminal 103 temporarily interrupts the measurement every time a predetermined time elapses and sequentially performs the self-diagnosis process, so that a large number of blind nodal type sensor terminals 103 can be obtained. It can be detected during the exploration of the reflected wave 112a that it is operating normally, and the reliability of the measured acceleration data can be maintained.

Further, since all the sensor terminals 103 do not have time to perform only the self-diagnosis process, the time required for exploration can be shortened and the exploration cost can be reduced. Further, in the second example, the frequency of self-diagnosis within the entire measurement period can be doubled as in the first example, so that the reliability of the measured acceleration data can be further improved.

In the second example above, by setting the time when the sensor terminal 103 starts the self-diagnosis process in the two exploration fields SF1 and SF2 at different times, the period of the self-diagnosis process of the sensor terminal 103 can be set to another. It is possible to prevent the period of the self-diagnosis process of the sensor terminal 103 from overlapping, but the period is not limited to this. Similar to the first example, the management device 10 may instruct the sensor terminal 103 to start the self-diagnosis process, and the start time of the self-diagnosis process is sequentially shifted so that the periods of the self-diagnosis process do not overlap. Can be ordered.

FIG. 7 is a diagram showing a third example of the timing of the vibration measurement of the sensor terminal 103 and the self-diagnosis process. The arrangement of the sensor terminal 103 and the movement of the earthquake simulation vehicle group 101 in the exploration field are the same as those in FIG. 6A.

The earthquake simulation vehicle group 101 first moves in the movement path 104 in the exploration field SF1, stops sequentially from each vibration point # (1, 1) to # (M, N) near the sensor terminal 103, and excites. (S in the figure) is performed. After that, the earthquake simulation vehicle group 101 moves along the movement path 104 in the exploration field SF2 in the same manner, and sequentially stops at each vibration point # (1, 1) to # (M, N) near the sensor terminal 103. , Vibration (S in the figure) is performed. The sensor terminals 103 arranged in the exploration fields SF1 and SF2 measure the acceleration of the reflected wave 112a (Receive).

In this third example, when the earthquake simulation vehicle group 101 excites at the point # (1, 1) in the exploration field SF1 at time t1, it is arranged at the point # (1, 1) in the exploration field SF1. Self-diagnosis processing (QC) is performed on the sensor terminal 103.

Subsequently, at time t2, when the earthquake simulation vehicle group 101 excites at the point # (1, 2) in SF1, self-diagnosis is performed by the sensor terminal 103 arranged at # (1, 1) in SF2. Perform processing. At time t3, when the earthquake simulation vehicle group 101 excites at the point # (1, 3) in the exploration field SF1, the sensor terminal 103 arranged at the point # (1, 2) in the exploration field SF1 Perform self-diagnosis processing (QC).

Subsequently, at time t4, when the earthquake simulation vehicle group 101 excites at the point # (1, 4) in SF1, the sensor terminal 103 arranged at # (1, 2) in the exploration field SF2 Perform self-diagnosis processing. At time t2MN-1, when the earthquake simulation vehicle group 101 excites at the point # (M, N) in the exploration field SF2, the sensor terminal 103 located at the point # (M, N) in the exploration field SF1. Performs self-diagnosis processing (QC) at.

Subsequently, at time t2MN, when the earthquake simulation vehicle group 101 excites at the point # (M, N) in the exploration field SF2, the sensor terminal arranged at the # (M, N) in the exploration field SF2. Perform self-diagnosis processing with. That is, the sensor terminals 103 in the exploration fields SF1 and SF2 alternately perform self-diagnosis from points # (1, 1) to # (M, N).

By sequentially performing the self-diagnosis process during the vibration measurement in this way, it is possible to detect during the exploration that a large number of blind nodal type sensor terminals 103 are operating normally, and it is possible to detect the measured acceleration data. Reliability can be maintained. Further, since all the sensor terminals 103 do not have time to perform only the self-diagnosis process, the time required for exploration can be shortened and the exploration cost can be reduced.

Further, the sensor terminal 103 that performs the self-diagnosis process cannot measure the acceleration data, and the acceleration data is lost. However, in the third example, since the terminals that continuously perform the self-diagnosis process are not adjacent to each other, the missing data is lost. It has the advantage of being spatially dispersed and reducing the degradation of data quality.

In the third example, the time for the sensor terminal 103 to start the self-diagnosis process is set to be staggered between the two exploration fields SF1 and SF2, so that the period for the self-diagnosis process of the sensor terminal 103 can be set to another. It is possible to prevent the period of the self-diagnosis process of the sensor terminal 103 from overlapping, but the period is not limited to this. Similar to the first example, the management device 10 may instruct the sensor terminals 103 of the two exploration fields SF1 and SF2 to start the self-diagnosis process, and the self-diagnosis process period is not overlapped. The start time of the diagnostic process can be sequentially shifted and commanded.

FIG. 8 shows the timing of transmitting the self-diagnosis result information from the sensor terminal 103 to the management device 10 of the observation vehicle 106 in the first example of the vibration measurement and self-diagnosis processing of the sensor terminal 103 shown in FIG. 3B. This is an example. In this first example, after the sensor terminal 103 performs the self-diagnosis processing QC, the corresponding signal (self-diagnosis result information) is transmitted regardless of whether the failure is OK or the failure is NG. The self-diagnosis result information includes the identifier of the sensor terminal 103.

In the first example, when the processor 204 of the sensor terminal 103 is out of order, neither the OK / NG signal is transmitted, so that the management device 10 of the observation vehicle 106 has the sensor terminal 103 caused by the processor 204. There is an advantage that the failure can be grasped. The self-diagnosis result information transmitted by the sensor terminal 103 includes the identifier of the sensor terminal 103.

On the other hand, FIG. 9 shows the timing of transmitting the self-diagnosis result from the sensor terminal 103 to the management device 10 of the observation vehicle 106 in the first example of the vibration measurement and self-diagnosis process of the sensor terminal 103 shown in FIG. 3B. Is an example of.

In this second example, after the sensor terminal 103 performs the self-diagnosis processing QC, the NG signal is transmitted to the management device 10 only when there is a failure and the NG is performed. In the second example, when the processor 204 of the sensor terminal 103 is out of order, the failure can not be detected, but the transmission power can be reduced and the life of the battery 208 can be extended. Further, the processor 204 is a pure electronic circuit as compared with the MEMS acceleration element 201, and the failure probability is considered to be small.

FIG. 10 shows a screen in which the management device 10 of the observation vehicle 106 receives an OK / NG signal (self-diagnosis result information) from the sensor terminal 103 and then displays the result.

In the window 1001 on the display device 14 (display), an area 1002 showing the layout of the sensor terminal 103 and an area 1004 showing the list of failed terminals are arranged.

The sensor terminal management unit 21 of the management device 10 generates sensor operation data 31 based on the self-diagnosis result information and position information received from the sensor terminal 103, generates a window 1001 from the sensor operation data 31, and displays the display device 14. indicate.

The position information may be acquired in advance from the GPS signal of the sensor terminal 103, or may be acquired in advance from another device. The sensor terminal management unit 21 of the management device 10 may store the identifier of the sensor terminal 103, the position information, the self-diagnosis result information, the time stamp, and the like.

In the area 1002 for displaying the layout (arrangement status) of the sensor terminal 103, the positions from # (1, 1) to # (I, J) and the icon 1003 indicating the sensor terminal 103 at that location are arranged. In the illustrated example, I = J = 4, and the sensor terminal 103 at # (1, 4) has failed, and a cross is added on the icon 1003 of the terminal and a list of failed terminals is displayed. # (1, 4) is displayed in the area 1004.

In this way, the management device 10 can intuitively understand the position of the failed terminal by displaying the failed sensor terminal 103 on the window 1001 of the display device 14 in the layout of the sensor terminal 103 and the list of failed terminals. Become.

When the failed terminal is found, the user of the management device 10 may replace the corresponding sensor terminal 103 immediately, or search as it is while the number of failed terminals is small and the influence on the measurement result is considered to be small. It may be continued and replaced when the number of failed terminals exceeds a certain value.

FIG. 11 is a diagram showing an example of processing performed at the time of starting, receiving, and self-diagnosis of the sensor terminal 103.

When the sensor terminal 103 is activated, the acceleration signal processing unit 202 (ASIC) adjusts the voltage VDC for the DC servo. Since the MEMS acceleration element 201 is placed in the exploration field and receives the gravitational acceleration of the earth, the heavy side (right side of the MASS layer) of the weight shown in FIG. 4C is tilted about the spring.

When a minute acceleration is measured in this state, the non-linearity of the measured value is large, so DC servo voltages VDC and VDC are applied to both ends of the DC servo capacitance CDR and CDR, and the weight (MASS layer) is almost applied by electrostatic force. Control horizontally. In this embodiment, an example in which only the DC servo voltage VDC is applied is shown, but the acceleration signal processing unit 202 (ASIC) increases or decreases the DC servo voltage VDC, and the acceleration detection capacitances CSL and CSR are equal at a constant value C0. Feedback control is performed so as to determine the optimum value V0 of the DC servo voltage VDC, and this optimum value V0 is stored in the memory 205.

When the sensor terminal 103 performs vibration reception processing, the DC servo voltage VDC is set to V0, and the gravitational acceleration is maintained in a canceled state.

On the other hand, during the self-diagnosis process shown in FIG. 4D, as described above, the value of the DC servo voltage VDC is once raised to VH and then lowered to VL in a short time to cause the resonance frequency of the weight (MASS layer). Add vibration with. At this time, the acceleration detection capacitance CSR vibrates at the resonance frequency f0 as shown in FIG. The processor 11 measures the Q value of resonance by calculating the damping constant of this vibration, and determines the presence or absence of a failure.

When the MEMS acceleration element 201 returns to the reception state after the self-diagnosis process is completed, the value of V0 stored in the memory 205 is read out and applied as the DC servo voltage VDC. As a result, it is not necessary to perform the optimization process of the DC servo voltage VDC, so that the return process can be performed in a short time.

FIG. 12 shows an example of processing at the time of starting, receiving, self-diagnosis, and calibration of the sensor terminal 103. When the sensor terminal 103 is used in a harsh environment, the characteristics of the MEMS acceleration element 201 may change over time.

For example, the high temperature may cause the weight (MASS layer) to warp, resulting in an imbalance of the paired capacitances. In such a case, it is effective to adjust the DC servo again and calibrate it before returning from the self-diagnosis to the reception process. The calibration method is not limited to the method described in this embodiment. By using this method, even if the characteristics of the MEMS acceleration element 201 change during work in the exploration field, this can be corrected and highly accurate acceleration data can be acquired.

As described above, according to the present embodiment, in the resource exploration system in which the reflected wave 112a of the vibration given to the ground surface by the oscillator 100 is measured by the plurality of sensor terminals 103, at least among the sensor terminals 103 in the exploration target area. One executes the self-diagnosis process, and the other sensor terminal 103 continues the measurement of the reflected wave 112a. Then, the sensor terminal 103 transmits the self-diagnosis result information including at least the failure as a result of the self-diagnosis to the management device 10. The management device 10 can update the sensor operation data 31 from the position information of the sensor terminal 103 acquired in advance and the received self-diagnosis result information, and output the window 1001 including the failure terminal list.

Exploration that the sensor terminal 103 is operating normally in a resource exploration system using a large number of blind nodal type sensor terminals 103 equipped with a MEMS acceleration element 201 that can be mass-produced at a low price like a MEMS sensor. It can be determined inside and the sensor can be calibrated if necessary.

Therefore, the accuracy and reliability of the measured acceleration data can be improved. Further, since it is not necessary to provide a special time for all the sensor terminals 103 to perform only self-diagnosis, the time required for exploration can be shortened and the exploration cost can be reduced. In addition, although the performance is excellent, it becomes possible to easily use a MEMS sensor that has just been put into practical use.

<Summary>
In the above embodiment, an example is shown in which the movable weight 402 is resonated and the Q value indicating the strength of resonance is measured from the change in capacitance, but the present invention is not limited to this, and the displacement of the movable weight 402 is not limited to this. As long as it can measure, for example, the displacement may be measured by a change in the magnetic field, a distance measurement by a laser beam, or the like.

In the above embodiment, an example in which the earthquake simulation vehicle 100 is used as the vibration source is shown, but the present invention is not limited to this, and an explosive or the like can be used.

The present invention is not limited to the above-described examples, and includes various modifications. For example, the above-described embodiment is described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to the one including all the configurations described. Further, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Further, for a part of the configurations of each embodiment, any of addition, deletion, or replacement of other configurations can be applied alone or in combination.

Further, each of the above configurations, functions, processing units, processing means and the like may be realized by hardware by designing a part or all of them by, for example, an integrated circuit. Further, each of the above configurations, functions, and the like may be realized by software by the processor interpreting and executing a program that realizes each function. Information such as programs, tables, and files that realize each function can be stored in a memory, a hard disk, a recording device such as an SSD (Solid State Drive), or a recording medium such as an IC card, an SD card, or a DVD.

In addition, the control lines and information lines indicate those that are considered necessary for explanation, and do not necessarily indicate all the control lines and information lines in the product. In practice, it can be considered that almost all configurations are interconnected.

10 Management device 100 Earthquake simulation vehicle 101 Earthquake simulation vehicle group 102 Earthquake simulation point 103 Sensor terminal 104 Movement path 105 Satellite 106 Observation vehicle 201 MEMS Acceleration element 202 Acceleration signal processing unit 203 External I / F
204 Processor 205 Memory 206 GPS receiver 207 Environmental sensor 208 Battery 401 MEMS chip 402 Movable weight 403 Spring 404 Anchor CSL, CSR Acceleration detection capacity CDR, CDR DC servo capacity CAL, CAR AC servo capacity SL, SR detection input Terminal DL, DR DC Servo Input Terminal AL, AR AC Servo Input Terminal VDC DC Servo Voltage 1001 Window 1002 Terminal Layout Area 1003 Terminal Icon 1004 Failure Terminal List

Claims (7)

A resource exploration system in which a plurality of sensor terminals are arranged in an exploration target area, and the plurality of sensor terminals measure the reflected wave of vibration oscillated from a vibration source.
The sensor terminal is
With the processor
With memory
With the sensor
A signal processing unit that converts the value detected by the sensor into data and stores it in the memory.
Has a communication unit,
The processor
At a predetermined timing, a self-diagnosis is executed to detect the presence or absence of an abnormality in the sensor, and self-diagnosis result information is transmitted.
The plurality of sensor terminals are
After starting the measurement of the reflected wave, the communication unit by executing the self-diagnosis for diagnosing the presence or absence of the own sensor abnormality at least one sensor terminal is temporarily suspends processing of the signal processing unit After the self-diagnosis result is transmitted and the self-diagnosis is completed, the measurement of the reflected wave is restored.
The sensor is
Including accelerometers applying MEMS technology
The signal processing unit
The acceleration detected by the acceleration sensor is converted into acceleration data and stored in the memory.
The acceleration sensor is
It has a movable portion that displaces according to the applied acceleration, a first electrode is provided on the movable portion, a second electrode is provided at a position facing the movable portion, and the first electrode and the second electrode are provided. The capacitance of the electrode is defined as the DC servo capacitance.
The processor
In the self-diagnosis, a Q value indicating the strength of resonance of the moving part is measured, and if the measurement result of the Q value is less than a predetermined threshold value, the self-diagnosis result of the sensor terminal is determined to have a failure. The self-diagnosis result is transmitted, and when the sensor terminal is activated, the optimum value of the voltage applied to the DC servo capacitance in order to cancel the gravitational acceleration applied to the moving part is detected. In the self-diagnosis, the DC servo is detected. By applying a voltage pulse to the capacitance, resonance is generated in the movable part to measure the Q value, and before returning to the measurement of vibration from the self-diagnosis, the gravitational acceleration applied to the movable part is canceled. A resource exploration system characterized in that the optimum value of the voltage applied to the DC servo capacitance of is detected again and calibration is performed. The resource exploration system according to claim 1.
The plurality of sensor terminals are spatially divided into a plurality of groups, and the plurality of sensor terminals are spatially divided into a plurality of groups.
The feature is that at least one of the sensor terminals included in each group performs self-diagnosis for diagnosing the presence or absence of its own abnormality while the plurality of sensor terminals are measuring the reflected wave. Resource exploration system. The resource exploration system according to claim 1.
The plurality of sensor terminals are included in a first group and a second group that are spatially divided.
Of the sensor terminals included in the first group and the sensor terminals included in the second group during the period when the plurality of sensor terminals are measuring the reflected wave. A resource exploration system characterized in that at least one sensor terminal alternately performs self-diagnosis. The resource exploration system according to claim 1.
The sensor terminal is
A resource exploration system characterized in that the self-diagnosis result is transmitted regardless of whether or not the sensor is out of order as a result of the self-diagnosis. The resource exploration system according to claim 1.
The sensor terminal is
A resource exploration system characterized in that when the sensor has a failure as a result of the self-diagnosis, the self-diagnosis result is transmitted. The resource exploration system according to claim 1.
It further has a second processor, a second memory, a communication device, and a management device including a display device.
The management device is
A first area indicating the arrangement status of the sensor terminal is generated from the position information of the sensor terminal acquired in advance.
Upon receiving the self-diagnosis result from the sensor terminal, the self-diagnosis result generates a second region containing a list of failed sensor terminals.
A resource exploration system characterized by outputting a screen including the first region and the second region to the display device. A resource exploration method in which a plurality of sensor terminals are arranged in an exploration target area, and the plurality of sensor terminals measure the reflected wave of vibration oscillated from a vibration source.
A first measurement in which the sensor terminal converts a value detected by a sensor including an acceleration sensor having a movable part that displaces according to an applied acceleration by applying MEMS technology into acceleration data and stores it in a memory. Steps and
After starting the measurement of the reflected wave, at least one sensor terminal temporarily interrupts the measurement and executes a self-diagnosis for diagnosing the presence or absence of an abnormality in its own sensor. The second step of measuring the Q value indicating the strength of resonance, and if the measurement result of the Q value is less than a predetermined threshold value, determining the self-diagnosis result of the sensor terminal as having a failure and transmitting the self-diagnosis result. When,
When the sensor terminal completes the self-diagnosis, the third step of converting the value detected by the sensor into data and returning to the measurement stored in the memory, and
Including
The acceleration sensor is
A first electrode is provided on the movable portion, a second electrode is provided at a position facing the movable portion, and the capacitances of the first electrode and the second electrode are defined as DC servo capacitances.
The first step is
When the sensor terminal is activated, the optimum value of the voltage applied to the DC servo capacitance in order to cancel the gravitational acceleration applied to the moving part is detected.
The second step is
By applying a voltage pulse to the DC servo capacitance, resonance is generated in the moving part and the Q value is measured.
The third step is
A resource characterized by re-detecting the optimum value of the voltage applied to the DC servo capacitance for canceling the gravitational acceleration applied to the moving part and performing calibration before returning to the vibration measurement from the self-diagnosis. Exploration method.

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