Experimental study on the relationship between sound velocity and energy anisotropy in limestone longitudinal and transverse waves
As oil and gas exploration and development gradually penetrate into complex unconventional reservoirs such as thin layers and tight formations,the issue of high input and low output caused by vertical well extraction methods becomes increasingly prominent.To address this problem,horizontal well technology has gained widespread application.However,horizontal wells are often surrounded by non-uniform formations,resulting in significant anisotropy in the formation adjacent to the wellbore.As a result,the measured acoustic properties of the reservoirs differ significantly from the actual conditions,impacting the accuracy of reservoir evaluation.Based on the theory of acoustic propagation,this study prepared five square limestone cores with distinct non-uniform layers for anisotropy measurement experiments.The influence of these non-uniform layers on longitudinal and shear wave velocities and energy was analyzed.The anisotropic relationship between acoustic velocity and energy was calculated and explored.The results indicate that the acoustic velocity anisotropy coefficient of the 5 cores ranges from 0.855 to 0.894,and the acoustic energy anisotropy coefficient ranges from 0.6208 to 0.8134,indicating pronounced anisotropic characteristics that align with the observed features of the cores.Furthermore,each sample exhibited approximately equal anisotropy coefficients of longitudinal and shear wave velocities,and a strong linear correlation was found between the anisotropy coefficient of longitudinal and shear wave velocity and the anisotropy coefficient of longitudinal and shear wave energy.These research findings provide valuable guidance and serve as a reference for further studies on anisotropy correction methods and reservoir evaluation techniques in horizontal well acoustic logging.
Acoustic waveAnisotropyAcoustic wave energyAcoustic wave velocityHorizontal well
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NSTL
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