Acoustic logging-while-drilling device of variable-diameter sound insulation structure

Abstract

The invention belongs to the field of applied geophysical exploration / acoustic logging, and particularly relates to an acoustic logging-while-drilling device of a variable-diameter sound insulation structure. The acoustic logging-while-drilling device of the variable-diameter sound insulation structure comprises drill collars, a sound wave transmitting device and a sound wave receiving device are arranged outside the drill collars, and the acoustic logging-while-drilling device is characterized in that a variable-diameter sound insulator is arranged between the sound wave transmitting device and the sound wave receiving device, and the drill collars comprise a drill collar with a first inner diameter and a first length, a drill collar with a second inner diameter and a second length, a drill collar with a third inner diameter and a third length and a drill collar with a fourth inner diameter and a fourth length from the transmitting device to the receiving device. The acoustic logging-while-drilling device lowers processing difficulty and cost, and meanwhile enhances the mechanical strength of the drill collars. Energy transfer between an energy converter and the drill collars is structurally obstructed, and the variable-diameter sound insulator is combined to further eliminate the interference of the drill collars to stratum signals.

Description

technical field [0001] The invention belongs to the field of application of geophysical exploration / acoustic logging, and in particular relates to a logging-while-drilling acoustic logging device with a variable-diameter sound-insulation structure. Background technique [0002] Compared with wireline logging, acoustic logging while drilling has the advantages of real-time measurement of formation compressional and shear wave velocities, real-time prediction of formation pressure, and little influence from mud invasion. At present, in horizontal wells, highly deviated wells and deep sea drilling, due to the high cost and high risk of wireline logging, acoustic logging while drilling has a tendency to replace wireline acoustic logging. [0003] So far, most of the sonic logging while drilling tools use a large number of grooves periodically or quasi-periodically carved on the inside and outside of the drill collar between the transmitting transducer and the receiving transduce...

AI Technical Summary

Problems solved by technology

The cost of research and development and processing of this kind of sound insulator structure is high, coupled with its damage to the strength of the drill collar and maintenance during use, the cost of acoustic logging while drilling is relatively high, which is not conducive to the development of acoustic logging while drilling promotion and use

In addition, existing quadrupole shear wave logging tools while drilling are greatly interfered by drill collar mode instrument mode waves in soft formations, and quadrupole wave dispersion is very serious in hard formations, resulting in inaccurate measurement of quadrupole shear wave velocity

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