A general experimental system for the development of acoustic logging tools

Tan

et al. 2021

Sensors

To obtain qualified logging while drilling (LWD) data, a new acoustic LWD tool was designed. Its overall design is introduced here, including the physical construction, electronic structure, and operation flowchart. Thereafter, core technologies adopted in this tool are presented, such as dominant exciting wave bands of dipole source, a sine wave pulse excitation circuit, broadband impedance matching, and an intellectualized active reception transducer. Lastly, we tested this tool in the azimuthal anisotropy module well, calibration well, and normal well, working in the model of the cable, sliding eye, and logging while drilling. Experiments showed that the core technologies achieved ideal results and that the LWD tool obtained qualified data.

Section: Experiments Of the Acoustic Lwd Toolmentioning

confidence: 99%

Design of a New Acoustic Logging While Drilling Tool

Tan

et al. 2021

Sensors

“…Simultaneously, the logging tool works in the downhole high-temperature environment, and the effect of different temperatures on the piezoelectric vibrator must also be considered. Experimental tests are an important method to study the performance of transducers [ 25 , 26 , 27 , 28 ]. The existing experimental research only considered the underwater acoustic characteristics of the transducer and did not pay attention to the temperature effects on the transducer [ 16 , 17 , 20 , 24 ].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on the Azimuthal-Transmitting Transducer of Acoustic Logging

Men

Che

2023

Sensors

Azimuthal acoustic logging can survey the downhole formation more accurately, and the acoustic source is the crucial component of the downhole acoustic logging tool with azimuthal resolution characteristics. To realize downhole azimuthal detection, assembling multiple transmitting piezoelectric vibrators in the circumferential direction is necessary, and the performance of azimuthal-transmitting piezoelectric vibrators needs attention. However, effective heating test and matching methods are not yet developed for downhole multi-azimuth transmitting transducers. Therefore, this paper proposes an experimental method to comprehensively evaluate downhole azimuthal transmitters; furthermore, we analyze the azimuthal-transmitting piezoelectric vibrator parameters. This paper presents a heating test apparatus and studies the admittance and driving responses of the vibrator at different temperatures. The transmitting piezoelectric vibrators showing a good consistency in the heating test were selected, and an underwater acoustic experiment was performed. The main lobe angle of the radiation beam, horizontal directivity, and radiation energy of the azimuthal vibrators and azimuthal subarray are measured. The peak-to-peak amplitude radiated from the azimuthal vibrator and the static capacitance increase with an increase in temperature. The resonant frequency first increases and then decreases slightly with an increase in temperature. After cooling to room temperature, the parameters of the vibrator are consistent with those before heating. Hence, this experimental study can provide a foundation for the design and matching selection of azimuthal-transmitting piezoelectric vibrators.

Journal of Geophysics and Engineering

Formation resistivity measurement based on a transient electromagnetic field excited by an acoustic probe in an open-hole

Sheng

Shen

2019

The monopole probe commonly used in acoustic logging can generate vibrations in its natural frequency under the excitation of the pulse signal, and excite transient electromagnetic (TEM) signals of the same frequency. The acoustic probe receives both acoustic and TEM field signals. The TEM field propagates and attenuates in conductive well fluid and formations, carrying formation resistivity information that could be used for formation evaluation. Based on the axisymmetry of the TEM field in an open-hole, theoretical calculation of the TEM field components in an open-hole model was performed. The results revealed that TEM response signals decay rapidly with time, and electric field intensity along the well axis Ez is approximately linear with formation resistivity. On this basis, we proposed a new method for measuring formation resistivity in an open-hole, which could supplement conventional logging methods. Also, it does not affect signal processing of acoustic logging and only applies the TEM signal to determine formation resistivity. The new method could accomplish a more comprehensive petroleum formation evaluation, which is of great significance to the integrated design of the well logging instrument.