An acousto-electric effect logging detector in boreholes

Well logging is performed in oil and gas exploration wells to obtain the physical characteristics of underground formations. Thereafter, these wells are cased. Through-casing logging is important in mature fields and for wells that are cased without logging due to borehole stability issues. Acoustic through-casing logging is a challenging issue due to the strong interference of casing waves in formation waves, especially when the casing and formation are poorly bonded. An acoustic tool with dual-source transmitters is developed, in which an additional transducer is added to suppress casing waves. First, the operation principle and the overall design of the tool are carried out, including the span distance between the two transmitting transducers and the spacing distance between the transmitting transducer and the receiving transducers. Thereafter, a dual-source transmitting circuit is designed to send out two excitation signals of opposite polarities. These signals possess good consistency, high emission power, and precise signal adjustment. Lastly, the tool is tested in cased exploration wells in China. The experiment endings show that about 90% of the casing waves are canceled. By suppressing the casing wave amplitude, the cased-hole acoustic logging can be used commercially to obtain trustworthy formation information.

Section: Overall Design Of the Acoustic Lwd Toolmentioning

confidence: 99%

Design of an Acoustic Through-Casing Logging Tool

Zhang

et al. 2022

“…Electrodes received a large interference signal at the zero moment, which was incidental to the work of the transmitting acoustic system. When logging, the interface acoustoelectric conversion wave arrives early, about 10 µs [11]. At this time, the amplitude of the interference is considerably larger than the interface acoustoelectric conversion wave, which causes it to be drowned.…”

Section: Introductionmentioning

confidence: 99%

Electrical Interference Simulation and Prediction Model for Acoustoelectric Logging Detector

Chen

Lü

et al. 2023

Self Cite

Acoustic logging instruments generate high voltages in the order of thousands of volts. Electrical interferences are thus induced by high-voltage pulses that affect the logging tool and make it inoperable owing to damaged components in severe cases. High-voltage pulses from the acoustoelectric logging detector interfere with the electrode measurement loop through capacitive coupling, which has seriously affected the acoustoelectric signal measurements. In this paper, we simulate high voltage pulses, capacitive coupling and electrode measurement loops based on qualitative analysis of the causes of electrical interference. Based on the structure of the acoustoelectric logging detector and the logging environment, an electrical interference simulation and prediction model was developed to quantify the characteristics of the electrical interference signal.

“…The whole detector was connected to the Eilog system during the field testing, and ideal results were obtained [23]. The China University of Petroleum developed a new generation of seismoelectric logging detectors, which are currently undergoing laboratory and field tests [24][25][26]. Guan et al proposed a method to invert permeability from seismoelectric logs in fluid-saturated porous formations, which has a guiding effect on actual data processing [27,28].…”

Section: Introductionmentioning

confidence: 99%

Design of a New Seismoelectric Logging Instrument

Zhang

Lü

et al. 2021

Self Cite

To increase the accuracy of reservoir evaluation, a new type of seismoelectric logging instrument was designed. The designed tool comprises the invented sonde-structured array complex. The tool includes several modules, including a signal excitation module, data acquisition module, phased array transmitting module, impedance matching module and a main system control circuit, which are interconnected through high-speed tool bus to form a distributed architecture. UC/OS-II was used for the real-time system control. After constructing the experimental measurement system prototype of the seismoelectric logging detector, its performance was verified in the laboratory. The obtained results showed that the consistency between the multi-channel received waveform amplitude and benchmark spectrum was more than 97%. The binary phased linear array transmitting module of the instrument can realize 0° to 20° deflection and directional radiation. In the end, a field test was conducted to verify the tool’s performance in downhole conditions. The results of this test proved the effectiveness of the developed seismoelectric logging tool.