Abstract: A calibration method under a near-bit wireless short-transmission ground environment includes the following steps: placing an emitter and a receiver, which are connected across a screw, in a container containing a solution, connecting the emitter with the receiver through a copper wire to form a loop of an electric field signal, connecting the emitter with a transmitting circuit to achieve signal transmission, connecting the receiver with a receiving circuit to achieve signal reception, and calibrating an optimal transmitting power and a receiving gain by measuring an amplitude relationship between a transmitted signal and a received signal in a case where resistivity values of solutions are different.

Abstract: In an apparatus for multi-pole acoustic logging while drilling, a N-cycle sinusoidal wave signal is generated by utilizing a signal processor, and amplified into a high-voltage sinusoidal excitation signal by utilizing a power amplifier, and output to a transmitting transducer. The signal processor simultaneously generates an enable signal. The enable signal includes a transient discharge enable signal. The power amplifier is connected with a transient discharge circuit. After the signal processor generates N cycles of a sinusoidal wave, the transient discharge enable signal enables the transient discharge circuit to discharge to release an energy storage current of a power transformer so as to eliminate a high-voltage ringing effect and improve an excitation efficiency of the transducer.

Abstract: A calibration method under a near-bit wireless short-transmission ground environment includes the following steps: placing an emitter and a receiver, which are connected across a screw, in a container containing a solution, connecting the emitter with the receiver through a copper wire to form a loop of an electric field signal, connecting the emitter with a transmitting circuit to achieve signal transmission, connecting the receiver with a receiving circuit to achieve signal reception, and calibrating an optimal transmitting power and a receiving gain by measuring an amplitude relationship between a transmitted signal and a received signal in a case where resistivity values of solutions are different.

Abstract: A magnetic field based micro-vibration measurement device and a measuring therefore are provided, which are applied in a micro-vibration measurement technical field. Fluxgate sensors and a control processing circuit are included. Each of the fluxgate sensors is disposed with an excitation coil and an induction coil that are mutually corresponding; the control processing circuit includes: an excitation signal generating module, a frequency-selective amplifying module, a phase-sensitive rectifying module, a smooth filtering module an ambient magnetic field acquisition module, and a vibration data statistics module. Excitation coils generate excitation magnetic field signals according to the excitation signal sent from the excitation signal generating module the induction coils are for generating induced current signals according to the receive excitation magnetic field signal and the ambient magnetic field signal.

Abstract: An electronic magnetometer and a method for measuring a magnetic field are provided. A Gunn diode with magnetic shielding and a Gunn diode without magnetic shielding generate different induced high-frequency oscillating currents in various environments. The high-frequency oscillating current of the Gunn diode with magnetic shielding and the high-frequency oscillating current of the Gunn diode without magnetic shielding are processed by circuits and subsequently compared. The difference of frequencies in the two currents is proportional to the magnitude of magnetic field, and the magnitude of magnetic field is obtained.

Abstract: A distributed electromagnetic method synchronization system and method involving a satellite communication and navigation system. The method includes the following steps: the transmitter and the receiver establish connection with the satellite respectively to realize the position and time synchronization; the transmitter and the receiver acquire the second-pulse-signal, and according to the second-pulse-signal to adjust their own temperature compensation crystal, so that the frequency reaches the preset value; in the field of operation, the transmitter and receiver through the satellite mutual communication, timely adjustment of the operation process. In the above-mentioned way, the communication function can be set in one place to facilitate the timely adjustment of the data acquisition process so as to ensure the quality of the collected data and improve the efficiency of the field operation.

Abstract: An apparatus for receiving signals in azimuthally acoustic LWD includes a drill collar body, a circuit mounting frame, a receiving transducer, a sealing connector, a preposed processing circuit module, a first receiving signal processing circuit for processing a signal from the transducer, distance detecting sensors, at least one set of plugging assemblies, an electrical connector and a second receiving signal processing circuit for processing signals from the distance detecting sensors. The circuit mounting frame is located inside the drill collar body and connected with the drill collar body. The receiving apparatus integrates a borehole diameter measurement system and an azimuthally acoustic while drilling receiving system on one drill collar.

Abstract: An azimuthally acoustic while drilling signal receiving transducer encapsulating apparatus includes a drill collar, a receiving transducer, a preposed signal processing circuit and a master control electronics housing. The receiving transducer and the preposed signal processing circuit are encapsulated on a drill collar body individually. The receiving transducer and the signal processing circuit are electrically connected by a sealing electrical connector. The preposed signal processing circuit and the master control electronic housing are electrically connected. The signal processing circuit is preposed in terms of signal processing, and encapsulated on the drill collar, so that signal receiving and processing cable length is shortened and noise interference is reduced.

Abstract: A receiving apparatus for downhole near-bit wireless transmission emission includes an electrical isolation drill collar and an internal electrical isolation short tube. The insulating subs are serially connected and disposed in the middle of the electrical isolation drill collar and the internal electrical isolation sub to realize electric isolation. The electrical isolation drill collar is electrically coupled with the internal electrical isolation short tube through a lantern stabilizer. The receiving apparatus further includes a wireless transmission receiving unit. The electrical isolation drill collar and the internal electrical isolation short tube of the receiving apparatus both have an electrical isolation function. The insulating subs in the electrical isolation drill collar and the internal electrical isolation short tube are non-detachable, and can meet downhole requirements for high torsion and high-pressure sealing property.

Abstract: A wear-leveling NandFlash memory reading/writing method can identify a bad block, avoid the bad block, and equalize writing operations to ensure that all the blocks are identical in number of the writing operations so as to guarantee wear-leveling NandFlash memory reading and writing of the entire memory. This method has characteristics of low computational and small RAM cost, is suitable for the application scenario like operating a single file for a long time with an imbedded system with low cost and poor hardware resource, and can provide a complete file system solution.

Abstract: A apparatus for downhole near-bit wireless transmission includes a bit connecting housing, a mud motor connecting housing, an insulating sub made of an insulating material. The insulating sub is serially connected between the bit connecting housing and the mud motor connecting housing to electrical insulate the bit connecting housing and the mud motor connecting housing from each other. The bit connecting housing and the mud motor connecting housing respectively form an electromagnetic transmitting positive pole and an electromagnetic transmitting negative pole. The mechanical apparatus further includes measurement units, which are configured to acquire parameters measured near the bit and a data transmitting unit, which is configured to realize wireless transmission; and the data transmitting unit is configured to receive and transmit the parameters measured near the bit.

Abstract: A receiving apparatus for downhole near-bit wireless transmission emission includes an electrical isolation drill collar and an internal electrical isolation short tube. The insulating subs are serially connected and disposed in the middle of the electrical isolation drill collar and the internal electrical isolation sub to realize electric isolation. The electrical isolation drill collar is electrically coupled with the internal electrical isolation short tube through a lantern stabilizer. The receiving apparatus further includes a wireless transmission receiving unit. The electrical isolation drill collar and the internal electrical isolation short tube of the receiving apparatus both have an electrical isolation function. The insulating subs in the electrical isolation drill collar and the internal electrical isolation short tube are non-detachable, and can meet downhole requirements for high torsion and high-pressure sealing property.

Abstract: A near-bit tool attitude MWD apparatus includes measurement sensors and a measurement circuit. The measurement sensors transmit measured signals to the measurement circuit, and the measurement circuit processes and calculates the signals to obtain attitude data. The measurement sensors include a triaxial accelerometer, a triaxial gyroscope, a triaxial magnetic sensor and a temperature sensor, the measured data of the triaxial accelerometer, the triaxial gyroscope and the triaxial magnetic sensor are respectively corrected using the measured data of the temperature sensor, a first attitude angle is calculated using the corrected measured data of the triaxial accelerometer and the triaxial magnetic sensor. Quaternions are initialized using the first attitude angle, and the initialized quaternions are subjected to time updating according to the measured data of the triaxial gyroscope, and further an attitude angle is calculated utilizing the updated quaternions.