Experimental study of the azimuthal performance of 3D acoustic transmitter stations

Abstract

Better well logging techniques for geologic investigations are urgently needed to identify and evaluate complex reservoirs. We describe a new type of 3D transmitter station with corresponding circuits and bodies. They can be used in a promising new technique of acoustic reflection well logging, that features better azimuthal detection capabilities, as well as better investigation depth. The transmitter stations consist of three-level subarrays that can radiate acoustic energy in any required azimuth of 3D space by circularly exciting various combinations at different levels. We tested the 3D acoustic transmitter stations and obtained laboratory directivity measurements with the 3D acoustic transmitter stations for the first time. The results show that the 3-dB beam width in the horizontal plane ranges from 59°to 67°as a result of phase-delayed excitation. The main beam is steered in the vertical plane at a deflection angle that ranges from 0°to 16°when the delay time of the excitation pulse between each pair of adjacent arc arrays is gradually adjusted. The 3-dB beam width is equal to 11°, whereas the deflection angle in the vertical plane is equal to 14°. Each of the four third-level subarrays in the same circumferential direction display consistent horizontal and vertical directivities, thus satisfying the requirements of azimuthal acoustic reflection logging.

Design of a New Acoustic Logging While Drilling Tool

“…Currently, most acoustic well logging transmitting transducers are fired by single-pulse excitation circuits, whose advantage is their simple structure and wide frequency band [ 28 , 29 , 30 , 31 ]. Meanwhile, the acoustic signal frequencies excited by these circuits is not adjustable, and the excited transducers only work at their resonance frequencies, no matter the impulse width of the excitation signals [ 32 , 33 , 34 ].…”

Design of a New Seismoelectric Logging Instrument

“…The amplitude of the received signal in seismoelectric logging is small, so it is necessary to improve the intensity of transmitted signal using an appropriate technology. According to the literature [30][31][32][33][34][35], a phased array acoustic logging radiator can improve the radiated sound field, the signal-to-noise ratio of received signal and the detection depth. Therefore, a phased array radiator is also included into this instrument.…”