粘声介质最小二乘逆时偏移及全波形反演研究

随着勘探程度的不断深入，油气勘探目标日趋复杂，高精度成像和建模方法面临更严峻挑战，如何实现复杂介质高精度成像、构建速度以及品质因子Q模型是亟待解决的科学难题。由于实际地下介质普遍存在粘滞性，地震波在传播过程中能量被介质吸收而发生衰减和频散，表现为频带变窄、主频降低、能量变弱，严重影响成像分辨率和地下参数反演建模。本项目基于分数阶拉普拉斯算子粘声波方程，研究粘声介质地震波传播特性，并以此作为理论基础，进一步研究高精度最小二乘逆时偏移成像，提高成像分辨率，准确定位地下构造；研究多目标多尺度粘声全波形反演构建速度-Q模型方法，降低其强非线性，提高双参数反演精度；拟将研究方法应用于大庆油田实际地震数据复杂目标成像以及速度-Q初始模型构建。本项目研究将有力推动地震偏移成像和速度-Q建模技术的发展进步，更好地服务于油田地震勘探，保障国家能源安全，具有重要的理论价值、应用前景和战略意义。

With the deepening of exploration degree, oil and gas exploration target is becoming more and more complex, high-precision imaging and modeling methods are facing more serious challenges, how to realize high-precision imaging for complex structure, building velocity model and quality factor Q model are urgent scientific problems to be solved. Due to the widespread viscosity of the actual subsurface medium, the energy of the seismic wave is absorbed by the medium during the propagation, leading to the attenuation and dispersion, which is characterized by the narrowing of the frequency band, the decrease of the main frequency and the weakening of the energy, which seriously affects the imaging resolution and the inversion modeling of the subsurface parameters. Based on the fractional Laplacians viscoacoustic wave equation, the project studies the characteristics of seismic waves propagation in viscous media, and takes this as the theoretical basis to further study the deep-layer imaging of high precision least squares reverse time migration, improve the imaging resolution and locate the underground structure accurately. The project also studies the method of constructing velocity-Q model for multi-objective and multi-scale viscoacoustic full waveform inversion to decrease its strong nonlinearity and improve the accuracy of two parameters inversion. Additionally, the research method is proposed to be applied to the complex target imaging of field data in Daqing oilfield and the initial model construction of velocity-Q. The research of this project will effectively promote the development of seismic migration imaging and velocity-Q modeling technology, better serve the seismic exploration of oilfields, and ensure national energy security, which has important theoretical value, application prospect and strategic significance.