VTI各向异性地层偶极横波测井及其应用

油气勘探开发中常利用测井声波(如斯通利波)数据评价慢速地层的横向各向同性(TI)特征,利用偶极弯曲波测量快速地层VTI各向异性。相对于单极斯通利波,快速地层中的偶极弯曲波对VTI各向异性有较高的灵敏度,用以反演地层的VTI各向异性参数,由此计算VTI地层的水平应力大小。将计算结果与由斯通利波得到的结果进行比较表明:在快速VTI地层中,利用新方法得到的地层弹性参数和各向异性大小更加准确,计算得到的水平地应力也更加可靠。

Using Dipole-shear Wave Logging to Characterize VTI Property and Its Application to Stress Estimation in VTI Formations

The Vertically Transverse Isotropy (VTI) property of hydrocarbon reservoir has traditionally been determined from borehole monopole Stoneley-wave measurements.We use flexural waves from dipole acoustic logging to estimate the VTI parameters.Compared to the Stoneley wave, the flexural wave has higher sensitivity to the VTI parameters in fast formations.Based on the sensitivity analysis, we use flexural waves to invert formation VTI parameters and use the inversion results to calculate horizontal stresses in fast VTI formations.The calculation results from field dipole data are compared with those from the monopole Stoneley wave data.The results show that the elastic parameters and VTI anisotropy from the flexural-wave inversion are more accurate and reliable.