Chinese Academy of Sciences

Yuntao Sun

Wenxiu Zhang

Wenxuan Chen

Jian Zheng

Qingyun Di

Yongyou Yang

Zili Wang

Fuqiang Wei

Jianguang Liu

Xin Fu

Changchun Yang

Yang Gou

A noise reduction measurement method of acoustic while drilling data based on signal synchronization is provided. The method performs pre-sampling before effective excitation of a low-frequency pulser, then extracts center frequency and phase information of noise of the low-frequency pulser by fast Fourier transform, and adjusts the excitation and sampling time of the acoustic signal according to the center frequency and phase information of the noise of the low-frequency pulser. Accordingly, the coincidence of the acoustic signal excited by the acoustic instrument and the acoustic signal generated by operation excitation of the pulser can be actively avoided, and the signal-to-noise ratio of the received signal of the acoustic instrument can be effectively improved.

Noise reduction measurement method of acoustic while drilling data based on signal synchronization

An acoustic while drilling receiving transducer array adopts a full-digital structure and a non-oil-filled rubber encapsulation arrangement mode, and the full-digital device of the acoustic while drilling receiving transducer array includes first modules, configured to carry out acoustic-to-electric conversion on weakly received acoustic signals of strata; second modules, configured to carry out amplification, filtering, gain control and digital-to-analog conversion on the weakly received acoustic signals; and a third module, configured to control interfaces of the device and convert external input and output signals.

Full digital device of receiving transducer array of acoustic logging while drilling instrument

An electrode-type near-bit wireless short-distance transmission modulation method includes the steps of by a near-bit measuring tool, measuring parameters, and acquiring parameter information, and packing the parameter information into a data packet, and transmitting the data packet to a transmission processor part; by the transmission processor part, performing binary frequency shift keying modulation on the data packet, and according to a set transmission power and driving source power, passing the modulated data packet through an amplifying circuit and a driving circuit, and then loading the modulated data packet to positive and negative electrodes of a transmitter; and by the positive and negative electrodes of the transmitter, transmitting the modulated data packet passed through the amplifying circuit and the driving circuit to a receiver, so as to realize electrode-type wireless short-distance transmission modulation.

Electrode type near bit wireless short distance transmission modulation method and apparatus

In a method for acquiring data of azimuthal acoustic LWD, when an acoustic LWD instrument rotates with a drilling tool at a certain depth, data is acquired by adopting an azimuthal equal-interval mode: a well circumference is divided into m sectors by azimuthal intervals &#x394;&#x3b8;, when a toolface angle of the acoustic LWD instrument is located in the ksector, an acoustic transmitting source is controlled to transmit an acoustic signal, and an acoustic receiver measures the acoustic signal, digitizes it and then stores it as data in the ksector; and the data is acquired for each sector in turn, and after the data is acquired in each sector for N times, the data acquisition at the current depth is completed. Meanwhile, as the drilling tool rotates and drills, the instrument acquires acoustic data at different depths and processes it to achieve azimuthal acoustic imaging.

Method for acquiring data of azimuthal acoustic logging while drilling

A sonic logging broadband impedance matching transformer modular design method and a module are related to sonic logging. The method includes the steps: obtaining component values of a multimodal equivalent circuit of a piezoelectric transducer by fitting actual impedance data of the piezoelectric transducer through a nonlinear regression method; selecting a T-type network structure composed of a matching capacitor and a matching inductor as a piezoelectric transducer impedance matching network structure; and presetting a to-be-matched frequency band and a reflection coefficient, and taking the multimodal equivalent circuit of the transducer as an artificial circuit load to optimize parameters of the piezoelectric transducer impedance matching network structure and a boosting transformer together so as to obtain final optimized parameters of the piezoelectric transducer impedance matching network structure and the transformer.

Sonic logging broadband impedance matching transformer modular design method and module

An apparatus for measuring gravity acceleration of a drilling tool comprises sensors and a measurement circuit. The sensor comprises a three-axis gravity accelerometer, a reference measurement sensor and a temperature sensor. The three-axis gravity accelerometer measures acceleration component signals in three mutually orthogonal directions, and the reference measurement sensor generates a signal that varies with rotation and is not affected by vibration or shock to serve as a reference signal. The temperature sensor measures the temperature in the apparatus to compensate the temperature effect of the gravity accelerometers. The measurement circuit acquires output signals of the sensors and performs cross-correlation processing on the accelerometer components using the reference signal to extract gravity acceleration signals so as to eliminate centrifugal acceleration, vibration, shock and other interferences generated by rotation. The non-interference gravity acceleration signals is used for calculating an inclination angle and a toolface angle of a drilling tool in the rotating state.

Gravity acceleration measurement apparatus and extraction method in a rotating state

A near-bit wireless constant current short-distance transmission device has an emission part and a receiving part. The emission part modulates a signal and then wirelessly transmits the modulated signal to the receiving part. The emission part transmits an emission signal into a stratum according to a set rated emission constant current value, and dynamically monitors and adjusts the rated emission constant current value of the emission signal to obtain stable emission power.

Near bit wireless constant current short distance transmission method and device

In a method for synchronizing acoustic asynchronous serial signals while drilling, communication and high-voltage signal isolation between a transmitting terminal and a receiving master control board are realized in an asynchronous serial communication way. The receiving master control board serving as a master control terminal configures parameters for the transmitting terminal in the asynchronous serial communication way and controls the excitation of a sound source. The transmitting terminal is a synchronous sound source excitation signal initiator; signal synchronization is realized under an asynchronous communication condition due to the coordination of the transmitting terminal and the receiving master control board; the transmitting terminal includes a plurality of transmitting boards, and asynchronous serial communication between each of the transmitting boards and the receiving master control board is realized through two data lines R+ and R.

Method for synchronizing acoustic asynchronous serial signals while drilling

The disclosure relates to the field of drilling tool attitude measurement, and particularly to a dynamic testing device suitable for a drilling tool attitude measurement module. The dynamic testing device may comprise a test fixture for attitude measurement module, an azimuth rotation device for adjusting an azimuth angle, an inclination angle swing device for adjusting an inclination angle, and a toolface angle rotation device for driving the test fixture for attitude measurement module to rotate, and a rotation speed measurement device for measuring a rotation speed and a self-rotation angle of the test fixture for attitude measurement module in a rotating state. The testing device has characteristics of large bearing weight, high rotation speed which is measurable and controllable, convenient for mounting and fixing a tested module, etc. It can simulate conditions of downhole rotation of a drilling tool, and be used for dynamic testing of the attitude measurement module.

Dynamic testing device suitable for drilling tool attitude measurement module

A near-bit constant-power wireless short-distance transmission apparatus includes a transmitting portion and a receiving portion. The transmitting portion is connected to a near-bit measurement sub while the receiving portion is connected to a measurement while drilling system. The transmitting portion processes data received by the bit measurement sub and then transmits it to the receiving portion. The receiving portion further processes the information and then transmits it to the measurement while drilling system. An insulating sub is inserted in the transmitting portion and separates the transmitting portion into a transmitting positive pole and a transmitting negative pole, which become electrically isolated from each other. Another insulating sub is inserted in the receiving portion and separates the receiving portion into a receiving positive pole and a receiving negative pole, which become electrically isolated from each other.

Near-bit constant-power wireless short-distance transmission method and apparatus

An azimuthal acoustic LWD apparatus is sequentially provided with a centralizer, a transmitting circuit, transmitting transducers, an acoustic insulator, a receiving transducer array, ultrasonic transducers and a receiving circuit on a drill collar. The azimuthal acoustic LWD apparatus is capable of operating in a dipole mode or a unipole mode, to cover all the sectors around a wellbore by adopting a fixed time interval measurement mode or an alternating time interval measurement mode according to a relationship of an interval between measurement times and a rotation speed of the apparatus, thereby achieving azimuthal acoustic LWD. This apparatus overcomes problems that the fixed time interval measurement mode may not cover all the sectors and further may not achieve azimuthal acoustic imaging in a case where the rotation speed and the interval between measurement times are under certain conditions.

Azimuthal acoustic logging while drilling apparatus and measurement method

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.

Sinusoidal excitation method and apparatus for multi-pole acoustic logging while drilling

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.

Apparatus for downhole near-bit wireless transmission

The present disclosure relates to the technical field of acoustic logging while drilling, and provides an integral packaging device for acoustic receiving transducers while drilling, wherein, the receiving transducers are directly arranged in a signal processing circuit, which is installed in an internal supporting frame fitted in a rectangular bellow; one side of the bellow has a deformable surface that is of a corrugated structure, and oil is filled in the bellow; the receiving transducers are arranged on the side that has a deformable surface; a shock absorbing rubber piece is of a U-shaped structure; one end of a connecting unit is connected to the signal processing circuit, and the other end of the connecting unit is connected to a main control circuit in a logging while drilling instrument. The present disclosure employs an integral packaging structure, which is easy to install structurally.

Integral packaging device for acoustic receiving transducers while drilling

An azimuthally acoustic imaging logging while drilling (LWD) apparatus employs two sets of transmitting transducers to excite multipole mode waves. One set is high-frequency monopole and polarized pole transmitting transducers, and the other set is low-frequency dipole and quadrupole transmitting transducers. Separation of a high-frequency transmitting state from a low-frequency transmitting state is realized by using a dual-row transmission solution. Each set of transmitting transducers operates at transducer resonance points through a matching circuit, thereby greatly increasing the transmitted energy. An operation mode of the azimuthally acoustic imaging LWD apparatus includes four kinds of transmitting modes of monopole, dipole, quadrupole and polarized pole; in terms of a sound insulator, a combined sound insulation mode of inner notch groove and inner reducers and tungsten rods is adopted; and signal reception may be realized by employing a high-sensitivity receiving transducer, which can effectively realize the signal reception.

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Beijing, China

Yuntao Sun