任意各向异性介质方位旅行时正演

Azimuth travel time forward modeling in arbitrary anisotropic media.

在研究任意各向异性介质中的旅行时正演方法时,针对含气裂隙和含水裂隙模型,本文给出了各向异性介质中射线追踪计算方法。计算结果表明:①在垂直裂隙情况下,纵波反射时间随炮检距、方位角变化,含气裂隙纵波反射时间的方位差异和炮检距差异更为明显;②在相同炮检距时,随着方位角变化反射波旅行时间呈近似椭圆规律变化,含气裂隙介质反射时间的方位差异比含水裂隙差异明显;③在不同裂隙面倾角情况下,反射波旅行时间的方位差异在裂隙面垂直时最为明显,然后随裂隙倾角的减小而减小,当裂隙面水平时变成方位各向同性介质;④在不同方位的测线中,以垂直裂隙走向测线的.纵波反射时间与平行于裂隙走向测线的纵波反射时间差异最大。

Faced at gas-bearing fractured model and oil-bearing fractured model, the paper presented ray-tracing computational method in anisotropic media when studying travel time forward modeling method in arbitrary anisotropic media. The computed results showed that ①in a scenario of vertical fracture-P-wave reflected times changed with offsets and azimuths and the azimuth difference and difference of offsets of P-wave reflected times in gas-bearing fractures are more distinct: ②in a condition of equal offsets, the travel times of reflections is approximately elliptic change with azimuths and the azimuth difference of reflected times in gas-bearing fractures is more distinct than in water-bearing fractures ;③in a scenario of different dips of fractured planes,the azimuth difference of travel times of reflections is the most distinct when the fractured planes is vertical and decreases with decreasing the dip of fractured plane and becomes azimuth isotropic media when the fractured planes is horizontal; ④on the lines with different orientation, the biggest time difference of P-wave reflections between the lines vertical and parallel to the fractured orientation exists.