碳酸盐岩储层叠前逆时偏移及GPU/CPU异构计算方案研究

针对碳酸盐岩储层地质构造的特点,提出采用基于声波方程的叠前逆时偏移算法对其进行成像,并在偏移过程中引入优化差分系数和完全匹配层(PML)边界条件来提高波场的数值模拟精度,同时利用GPU/CPU异构并行加速技术对算法进行优化,从而显著提升偏移的计算效率。模型测试表明,与传统差分系数相比,同阶的优化差分系数具有更高精度,压制频散效果明显;PML边界条件能够有效的吸收边界反射,减少边界反射对有效波场的干扰;叠前逆时偏移方法可有效识别碳酸盐岩模型中的小尺寸孔洞和裂缝,归为准确,刻画清晰,对碳酸盐岩储层成像具有显著优势;GPU/CPU异构并行加速技术可明显提高偏移的计算效率,与传统CPU算法相比,加速比可达60倍,对于实际推广应用具有重要意义。

Carbonate Reservoir Pre-stack Reverse-time Migration and GPU/CPU Heterogeneous Computing Research

Theprestack reverse-time migration based on acoustic wave equationwasadopted in imaging carbonate reservoir. In the process of migration, optimized differential coefficient and perfectly matched layer （PML） boundary conditionwereusedto improve the accuracy of numerical simulation, and GPU/CPU heterogeneous parallel acceleration technologywasalso used to improve calculation efficiency. Model tests indicate that,comparedwith the traditional differential coefficient, the optimized coefficient with the same order has higher accuracy,and dispersion is suppressed obviously; PML boundary conditioncanabsorbboundary reflection effectively and reduceinterference effectively. Prestack reverse-time migration can identify small carbonate holes and cracks in the model, depict them clearly and accurately, it has significant advantage in imaging carbonate reservoir;GPU/CPU heterogeneous parallel technique can obviously improve the migration computation efficiency, compared with the traditional CPU algorithm, speed ratio can reach 60 times, is of great significance for actual application.