| 摘要: |
| 推导基于二维交错网格的二阶和四阶频率域弹性波有限差分算子,并结合最优化差分系数和质量加权平均方法压制数值各向异性。基于均匀各向同性介质比较不同差分算子的模拟精度和频散关系,并详细比较二阶算子和四阶算子的精度和误差量级。结果表明,当采用交错网格最优化四阶差分算子,单位横波波长内含3个及以上网格点时,可将模拟误差控制在2％以内。同时,相对于常规网格,基于交错网格的差分算子可用于对含流体介质模型的模拟。 |
| 关键词: 频率域 交错网格 有限差分算子 数值各向异性 |
| DOI：10.3969/j.issn.1673-5005.2014.05.007 |
| 分类号::P 631.4 |
| 基金项目:国家“973”重点基础研究发展计划(2013CB228605);国家自然科学基金项目(41374141) |
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| Accuracy comparison and improvement strategy in numerical modeling of elastic wave in frequency-domain by high-order finite-difference scheme |
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MA Chao1, SHEN Jinsong1,2,3, LI Xining1
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(1.College of Geophysics and Information Engineering in China University of Petroleum, Beijing 102249, China;2.State Key Laboratory of Petroleum Resources and Prospecting in China University of Petroleum, Beijing 102249, China;3.CNPC Key Lab of Geophysical Exploration in China University of Petroleum, Beijing 102249, China)
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| Abstract: |
| D finite-difference operators in second-order as well as fourth-order accuracy based on staggered grid in frequency-domain are derived. By combining optimal difference coefficients with lumped mass methods with a weighted average, numerical anisotropy can be suppressed, which enables accurate dispersion comparisons among these difference operators. Using a homogeneous isotropic medium, simulation precisions of different operators are compared to contrast the accuracy and error magnitude between second-order and fourth-order operators. It appears that the resulting error is smaller than 2％ if the number of grid points required per smallest shear wavelength increases to 3. Meanwhile, in contrast to those based on conventional grid, difference operators based on staggered grid can be conducted in model simulations in fluids. |
| Key words: frequency-domain staggered-grid finite-difference operator numerical anisotropy |
