Numerical Simulation and Parametric Analysis of Cross-Dipole Acoustic Logging Responses in HTI Formations
Abstract
However, the response of four-component dispersion curves to γ remains insufficiently understood, limiting the quantitative use of dispersion data in anisotropy-parameter inversion. To investigate this response, cross-dipole excitation along the X and Y directions was simulated using a velocity–stress staggered-grid finite-difference method with convolutional perfectly matched layers, yielding XX, XY, YX, and
YY array waveforms. With other model conditions fixed, γ was varied from 0.05 to 0.30. Dispersion curves were extracted using weighted
spectral semblance, and the response mechanism was examined in terms of elastic-stiffness variations and borehole-wave propagation. The
results show that increasing γ shifts the principal XX and YX flexural-wave dispersion curves toward lower slowness, with larger slowness
shifts at low to intermediate frequencies, whereas the YY component changes only slightly. γ affects the X-polarized flexural-wave velocity primarily by changing c66. The high-slowness trajectories in the XY component are attributed mainly to Stoneley waves. These results
clarify the relationship between γ and the four-component dispersion responses and provide a numerical basis for anisotropy-parameter
identification in HTI formations.
Keywords
Full Text:
PDFReferences
[1] THOMSEN L. Weak elastic anisotropy[J]. Geophysics, 1986, 51(10): 1954-1966.
[2] WU X G, JI F L, LI D C. Application status and research progress of dipole acoustic logging technology[J]. Progress in Geophysics,
2016, 31(1): 380-389 (in Chinese).
[3] ALFORD R M. Shear data in the presence of azimuthal anisotropy: Dilley, Texas[C]//SEG Technical Program Expanded Abstracts 1986.
Houston: Society of Exploration Geophysicists, 1986: 476-479.
[4] SINHA B K, NORRIS A N, CHANG S K. Borehole flexural modes in anisotropic formations[J]. Geophysics, 1994, 59(7): 1037-1052.
[5] CHENG N, CHENG C H, TOKSÖZ M N. Borehole wave propagation in three dimensions[J]. The Journal of the Acoustical Society of
America, 1995, 97(6): 3483-3493.
[6] WANG R J, QIAO W X, JU X D, et al. Experimental study of acoustic fields excited by dipole sources with different polarization directions in a borehole penetrating an HTI formation[J]. Chinese Journal of Geophysics, 2013, 56(2): 707-717 (in Chinese).
[7] KOMATITSCH D, MARTIN R. An unsplit convolutional perfectly matched layer improved at grazing incidence for the seismic wave
equation[J]. Geophysics, 2007, 72(5): SM155-SM167.
[8] VIRIEUX J. P-SV wave propagation in heterogeneous media: Velocity-stress finite-difference method[J]. Geophysics, 1986, 51(4): 889-901.
[9] MOCZO P, KRISTEK J, VAVRYÄŒUK V, et al. 3D heterogeneous staggered-grid finite-difference modeling of seismic motion with
volume harmonic and arithmetic averaging of elastic moduli and densities[J]. Bulletin of the Seismological Society of America, 2002,
92(8): 3042-3066.
[10] KIMBALL C V, MARZETTA T L. Semblance processing of borehole acoustic array data[J]. Geophysics, 1984, 49(3): 274-281.
DOI: http://dx.doi.org/10.70711/frim.v4i9.10221
Refbacks
- There are currently no refbacks.
