Azimuthally acoustic logging tool to evaluate cementing quality

Self Cite

A logging-while-drilling (LWD) caliper is a tool used for the real-time measurement of a borehole diameter in oil drilling engineering. This study introduces the mechanical structure and working principle of a new LWD caliper based on ultrasonic distance measurement (UDM). The detection range is a major performance index of a UDM system. This index is determined by the blind zone length and remote reflecting interface detection capability of the system. To reduce the blind zone length and detect near the reflecting interface, a full bridge acoustic emission technique based on bootstrap gate driver (BGD) and metal-oxide-semiconductor field effect transistor (MOSFET) is designed by analyzing the working principle and impedance characteristics of a given piezoelectric transducer. To detect the remote reflecting interface and reduce the dynamic range of the received echo signals, the relationships between the echo amplitude and propagation distance of ultrasonic waves are determined. A signal compensation technique based on time-varying amplification theory, which can automatically change the gain according to the echo arrival time is designed. Lastly, the aforementioned techniques and corresponding circuits are experimentally verified. Results show that the blind zone length in the UDM system of the LWD caliper is significantly reduced and the capability to detect the remote reflecting interface is considerably improved.

Section: Echo Signal Compensation Techniquementioning

confidence: 99%

Acoustic Emission and Echo Signal Compensation Techniques Applied to an Ultrasonic Logging-While-Drilling Caliper

Yao

et al. 2017

Self Cite

“…A linear array changes the vertical directivity of an acoustic beam, while an arc array affects the horizontal directivity. The arc-array source has been combined with an azimuth-array receiver to evaluate the cementing quality azimuthally in a cased hole [ 18 ]. However, owing to the limited tool space, the energy from the arc-array source is too small to be widely used in borehole acoustic reflection imaging.…”

Section: Introductionmentioning

confidence: 99%

A Plasma Transmitting Source for Borehole Acoustic Reflection Imaging

Hao

Zhou

Shang

et al. 2022

The detection depth of current borehole acoustic reflection imaging is only tens of meters without high resolution. This considerably limits its wide application in the identification and fine description of unconventional reservoirs and in the optimization of drilling trajectories. Increasing the directional energy from the transmitter to a geological structure is an excellent way to solve this issue. In this study, a plasma source with a parabolic reflector was introduced during borehole acoustic reflection imaging. First, an experimental system was built for testing the plasma source. Next, the acoustic-electrical characteristics and directional radiation of the source were studied using experiments and a numerical simulation. Finally, the advantages, disadvantages, and feasibility of the plasma-transmitting source were analyzed; some suggestions for further work on the source and its logging application were proposed. The experimental and simulation results show that the use of a plasma source with a parabolic reflector can increase the detection depth of borehole acoustic reflection imaging to hundreds of meters with high resolution. This is crucial in imaging the geological structures near boreholes and enhancing oil–gas exploration and development.

“…Acoustic logging adopts transmitting transducers to transform electric signals into acoustic signals, which then propagate into the deep underground layer, and are finally collected by receiving transducers. These signals are stored and analyzed for oil and gas exploration and exploitation [ 1 ]. Traditional acoustic logging proceeds after drilling and cementing; however, acoustic logging while drilling (LWD) not only rapidly obtains traditional acoustic logging messages, but also predicts the reservoir pressure to improve drilling security, and obtains formation messages to guide the drilling orientation [ 2 , 3 ].…”

Section: Introductionmentioning

confidence: 99%

Design of a New Acoustic Logging While Drilling Tool

Zhang

Tan

Zhang

et al. 2021

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.