Measurement of the shear slowness of slow formations from monopole logging-while-drilling sonic logs

Su, Yuanda1; Fang, Xinding2; Tang, Xiaoming1

2020

10.1190/GEO2019-0236.1

GEOPHYSICS   影响因子和分区

0016-8033

1942-2156

Acoustic logging-while-drilling (LWD) is used to measure formation velocity/slowness during drilling. In a fast formation, in which the S-wave velocity is higher than the bore-holefluid velocity, monopole logging can be used to obtain P-and S-wave velocities by measuring the corresponding refracted waves. In a slow formation, in which the S-wave velocity is less than the borehole-fluid velocity, because the fully refracted S-wave is missing, quadrupole logging has been developed and used for S-wave slowness measurement. A recent study based on numerical modeling implies that monopole LWD can generate a detectable transmitted S-wave in a slow formation. This nondispersive transmitted S-wave propagates at the formation S-wave velocity and thus can be used for measuring the S-wave slowness of a slow formation. We evaluate a field example to demonstrate the applicability of monopole LWD in determining the S-wave slowness of slow formations. We compare the S-wave slowness extracted from a monopole LWD data set acquired in a slow formation and the result derived from the quadrupole data recorded in the same logging run. The results indicated that the S-wave slowness can be reliably determined from monopole LWD sonic data in fairly slow formations. However, we found that the monopole approach is not applicable to very slow formations because the transmitted S-wave becomes too weak to detect when the formation S-wave slowness is much higher than the bore-holefluid slowness.

SCI ; EI

英语

通讯

National Natural Science Foundation of China[41704112] ; National Natural Science Foundation of China[41774138]

Geochemistry & Geophysics

Geochemistry & Geophysics

WOS:000506219100009

SOC EXPLORATION GEOPHYSICISTS

20213510840731

Acoustic logging ; Acoustic wave velocity ; Acoustics ; Boreholes ; Infill drilling ; Shear waves ; Wave propagation

Oil Field Production Operations:511.1 ; Acoustics, Noise. Sound:751 ; Mechanics:931.1

GEOSCIENCES

Web of Science

1.China Univ Petr, Sch Geosci, Qingdao 266555, Peoples R China
2.Southern Univ Sci & Technol, Dept Earth & Space Sci, Shenzhen 518055, Peoples R China

Su, Yuanda,Fang, Xinding,Tang, Xiaoming. Measurement of the shear slowness of slow formations from monopole logging-while-drilling sonic logs[J]. GEOPHYSICS,2020,85(1):D45-D52.

Su, Yuanda,Fang, Xinding,&Tang, Xiaoming.(2020).Measurement of the shear slowness of slow formations from monopole logging-while-drilling sonic logs.GEOPHYSICS,85(1),D45-D52.

Su, Yuanda,et al."Measurement of the shear slowness of slow formations from monopole logging-while-drilling sonic logs".GEOPHYSICS 85.1(2020):D45-D52.