【作者】 陈辉；

【导师】 李录明； 罗省贤；

【作者基本信息】 成都理工大学 ， 地球探测与信息技术， 2009， 博士

【摘要】 随着油气勘探的不断深入,所面临的勘探对象和开发条件也越来越复杂,为了有效解决复杂地表地区或复杂油气藏的勘探、开发问题,就必须发展新的、适用于复杂介质的偏移成像算法,并利用其获取精确的偏移速度。基于此,本文系统地研究了波动方程叠前深度偏移及偏移速度分析中的几个关键问题,这对复杂介质波动方程偏移和偏移速度分析具有较好的应用价值和实际意义。本文研究工作主要集中在以下几个方面:(1)系统地研究了常规偏移算子与保幅偏移算子,论证了保幅偏移算子的优越性。通过对理论模型叠后正演和偏移,总结分析了各种偏移算子的适应性问题,为实际应用提供参考。(2)利用单程波叠前正演波场模拟客观的评价了偏移算法,避免了双程波正演的不足。通过对比水平地表和起伏地表两种情况下的波场特征,分析了由于复杂地表引起的波形畸变,为正确认识复杂地质条件下的波场特征提供了研究基础。(3)实现了单平方根与双平方根叠前深度偏移算法。虽然两类偏移算法理论上是等价的,但是在具体应用中存在着较大差异。本文详细对比了两类偏移算法的异同点,并指出双平方根偏移的计算效率更高,更有利于为偏移速度分析和AVO/AVA分析输出偏移距域共成像点道集或角度域共成像点道集。(4)将双平方根保幅偏移算子应用于共成像点道集的抽取,保证了共成像点道集的振幅能量特征。系统地研究了各种共成像点道集对多射线路径的适应性。在此基础上,采用剩余曲率分析法和深度聚焦分析法,分析了各种共成像点道集对偏移速度的敏感性,论证了射线参数域共成像点道集应用于偏移速度分析的可行性,为偏移速度建模提供了研究基础。(5)本文基于MPI并行技术,将偏移及共成像点道集分析串行算法并行化,取得了较好的并行效率和并行加速比。为了适应多核技术的发展和应用,提出了MPI+OpenMP多层次并行偏移和速度分析技术,该技术在考虑负载均衡的前提下,充分发挥了多核性能,在实际生产中具有广阔的应用前景。(6)在理论研究的基础上,对我国海上某勘探区块的实际资料进行处理。首先对实际资料进行了交互偏移速度分析,求取了较高精度的层速度模型,将其应用于叠前深度偏移,成像效果良好。通过偏移得到的共成像点道集也验证了层速度模型的正确性。更多还原

【Abstract】 With the development of oil and gas exploration, exploration targets and conditions have become more and more complex, in order to effectively solve the exploration of complex surface area or complex oil and gas reservoir, it is necessary to develop the new migration imaging algorithms, applicable to the complex medium, and obtain precise migration velocity. Based on the above described, the thesis studies some key issues in the wave equation prestack depth migration and migration velocity analysis, and has better applied value and practical significance for wave equation migration and migration velocity analysis in complex areas. The studies in this thesis mainly focus on the following aspects:(1) The thesis studies common migration operator and amplitude-preserved migration operator, and verifies advantages of the amplitude-preserved migration operator. Through post-stack forward and migration based on theoretical models, the thesis makes a summary about adaptability of various migration operators, and provids the references for practical application.(2) The thesis evaluates migration algorithms using one-way wave pre-stack forward wave-field simulation, avoiding the weakness of two way wave, and analysises the waveform distortion caused by complex surface through comparing wave field characteristics of horizontal surface and relief surface, and provides the basis for understand correctly wave-field characteristics in complex geologic condition.(3) The thesis realizes the pre-stack depth migration algorithms based on single square root and double square root, although the two algorithms are equivalent theoretically, but have larger differences in pratical applications. The thesis compares the similarities and differences between two algorithms, and verified that double square root migration is more efficient, and is more better to output the offset domain common image gathers or angle domain common image gathers for migration velocity estimation and AVO/AVA analysis.(4) The amplitude-preserved migration operator based on double square root is applied to common image gathers extraction for the first time, and ensure the correctness of amplitude energy features. The adaptability of common image gathers for multi-ray paths has been studied. On this basis, the thesis analysises the sensitivity of various common image gathers for migration velocity through the residual curvature analysis and depth-focusing analysis, and proves the feasibility of applying common image gathers to migration velocity analysis, and provides the study foundation for migration velocity modeling.(5) The thesis realizes migration and common image gathers analysis by replacing the serial algorithms with parallel algorithms based on MPI parallel technology, and achieves high parallel efficiency and speedup. In order to adapt to the development and application of multi-core technology, multi-level parallel method of migration and velocity analysis based on MPI and OpenMP is proposed, the method gives full play to multi-core performance considering load balancing, and has broad application prospects.(6) The thesis processes practical data about some exploratory area on sea in our country. After the interactive migration velocity analysis for practical data, the higher accuracy level velocity model has been obtained, and it is applied to pre-stack depth migration, the migration imaging result is better. Common image gathers obtainted by migration verifies the correctness of level velocity model.更多还原