【作者】 单刚义；

【导师】 韩立国；

【作者基本信息】 吉林大学 ， 地球探测与信息技术， 2011， 博士

【摘要】 随着国民经济的快速发展,国内对能源的需求也越来越紧张。为了加大对能源的储备,地震勘探的重心从东部平原地区向中西部山地、高原地区转移。在这些地区,蕴藏着丰富的石油天然气,相继发现了克拉玛依油田、塔里木油田、吐哈油田等一些大的能源基地。但是在这些地区,沙漠、山地、高原等复杂的地形构成了不同于东部地区的复杂地质结构,因此,基于共中心点(CMP)的野外采集方式已经不适合复杂的地质条件。对于新的探区,野外地震勘探投资大,风险高,为了提高经济效益,迫切需要一种技术手段能够对新探区的采集参数进行模拟和研究分析,通过参数论证和应用研究,优化野外采集的观测系统,提高对勘探目标的勘探精度,为寻找新的隐伏油气藏提供理论指导和技术支持。限差分算子,并且进一步研究了其稳定性、收敛性和频散关系。在地震勘探中,人工激发的地震波在岩石中传播,地震波遇到介质会发生反射、透射等波的运动形式,通过这种介质的机械振动研究岩石的物理特性。岩在野外地震勘探初期,地震采集方式可以通过模拟地质构造进行参数论证,对地震覆盖次数、偏移距、道距等采集参数进行室内模拟,因此,通过模拟获得的结论进行勘探目标的验证,进而修改采集参数,提高勘探效益。常规的建模技术是建立在水平层状介质的基础上,这种建模方式简单,对我国东部平原地区比较适合,但是对中西部高原地区由于复杂的地质结构进行模拟变得非常困难。本文在研究常规建模的基础上引入了点、断、面的二维建模方法,通过模拟西部复杂的逆掩断层等地质结构取得了较好效果。波动方程正演方法不同于野外地震勘探,由于计算机硬件的限制,因此造成了人为的边界问题,同时由于是室内模拟也产生了对震源问题的研究。为了对波的传播这种连续问题离散化,国内外学者都在研究过程中获得了许多成果。在边界问题的研究中先后推导出了像完全吸收边界等一些效果明显的边界解决方法。通过对野外震源特性的研究分析,先后研究出了许多子波函数表达式,结合地震勘探的特点,其中一种能够模拟野外震源的雷克子波在波场模拟中得到了广泛运用,这种子波具有分辨率高、频带宽的特点。在研究地震波传播的波场特征时,正演模拟是一种不可缺少的手段。地震波数值模拟主要分为几何射线法和波动方程法两大类。几何射线法是在高频近似的前提下模拟波的传播过程的,它主要反映波的运动学特征,而波动方程法在模拟波的传播过程时不但能提供波的运动学特征还能反映波在介质中的动力学参数,因此,波动方程法正演模拟得到了更广泛的应用。随着计算机软件、硬件的飞速发展,数值模拟技术在各个领域得到了迅速应用。在数值模拟技术发展中研究出了许多波动方程模拟方法,主要有有限元法、伪谱法和有限差分法,其中有限差分法编程简单,能够模拟各种地质结构,在地震波数值模拟中得到了广泛应用。由于对连续问题离散化,从简单的声波方程出发推导出了波动方程的有石圈中普遍存在各向异性介质即横向各向同性介质,从广义的胡克定律出发,根据描述弹性介质运动的微分方程建立了有限差分公式,以有限差分算子为基础进行地震照明模拟,通过对纵波和横波(本文主要指转换横波SV波)的模拟照明,得出了有意义的结论,对提高野外勘探效益有一定的指导意义。地震照明能够模拟野外地震勘探采集方式,优化采集观测系统的设计,降低投资风险,提高经济效益,因此,经常作为一种评价野外采集的方法手段。地震勘探采集参数(激发震源的药量、排列的接收方式、道距、偏移距等)以及地下地质构造是影响地震照明的因素。最先用于对地震照明研究的方法是射线追踪,这种方法在基于水平层状结构的地质模型中能够很好的反映地震波在介质中的照明度。随着地震勘探的目标区越来越复杂,由于射线追踪法本身的缺陷已经不能适应复杂的地质模型,经常在模拟过程中得出不合理的结论。由于波动方程能够适应复杂的地质条件,能够提供更多的波场信息,有助于研究介质的物性参数。通过建立复杂的地质模型,模拟地下隐伏的含油气蕴藏环境,对不同的地质模型通过变换多种采集参数得到不同的照明结果进行分析,可以对勘探目标的采集方式进行优化,提高勘探精度,使在基于共反射点的观测系统的设计上进一步提高采集参数的优化,真正实现基于勘探目标的野外采集方式,为提高经济效益提供理论指导和技术支持。地震资料去噪技术是地震勘探过程的一个重要环节,如何把采集的资料经过处理达到真正反映地下地质结构的成果,去噪技术发挥了重要作用,特别是在复杂的地质条件影响下,解决长波长、短波长校正量问题也是一个重要研究课题。通过对复杂地质条件下的地质构造进行地震照明和地震资料处理,得到了较好的成果,对进一步研究复杂地质构造积累了经验。更多还原

【Abstract】 Domestic demand for energy is more and more tensely along with the rapid development of the national economy.In order to increase the energy reserves, the strategic center of the sei-smic exploration has been moved from the eastern plain areas to the Midwest mountain and pl-ateau regions. Some big oilfields have been successively found in these areas, rich in oil and gas. such as Kelamayi oilfield、Talim oilfield and Tuha oil field. But in these areas, it is different from the eastern regions with the complex geological structure. Therefore, the acquisition methods based on CMP are not suitable for complicated geological conditions. Seismic exploration has large investment risk for the new exploraion areas.In order to improve the economic benefit,some new exploration techologies will be used to study and analysis the collection parameters in desperate need, which will optimize the field collection observation system and improve the accuracy of exploration targets and provide theoretical guidance and technical support for searching the new concealed reservoirs.In the field seismic exploration early.it can be simulated for the geological structure parameters of argumentation,such as seismic folds、offset and recevers indoor simulation.Therefore, it can modify the gathering parameters and increase the exploration benefit by the conclusion obtained in exploration simulation.It is simple to establish the layered media on the basis of the conventional modeling technology and it is suitable for the eastern plain area but not for the Midwest plateau due to the complicated geological structure.In this thesis, it will be introduced a new two-dimensional modeling method by studying the conventional modeling.its basic elements are dot、broken and surface. The new modeling method is successful in the sim-ulation of the overthrust fault in the western complex geological structure.Because the computer hardware restrictions and the man-made boundary issue.the wave equation modeling algorithm is different from the wild seismic exploration. At the same time,we must study the source in the indoor simulation. In order to discrete the continuous problem, scholars at home and abroad have received many achievements in the process of studying the wave propagation. There are some good effect in the studying boundary problem.such as fully absorting boundary. Many wavelet function have been successively developed by the research and analysis of the source characteristics. One of the famous wavelets is Ricker wavelet, and it has been widely used in the wave field sim-ulation with the high resolution wade frequency characteristics.The forward modeling is a useful tool in the study of the wave field characteristic. There are two methods to simulate the seismic wave propagation.geometric ray method and wave equation method. Geometric ray method simulate the seismic wave propagation on the base of the high frequency approximation, it mainly reflects the wave of kinematic features, and wave equation method can not only provide the wave of kinematic features but also reflects the wave of the kinetic parameters. Therefore,the wave equation method has been applied extensiveely in the forward modeling. Along with the rapid development of the computer software and hardware, the numerical simulation technology has been used in many fields. In the wave equation simulation technology,there are three numerical simulation methods, including finite element method、the method of pseudo-spectral and finite difference method. Because of the simple and simulating various geological structure,the finite difference method has been used widely. In the process of studing the wave propagation with the discretization problem, the finite difference operators has been deduced, at the same time, its stability、convergence and frequency dispersion relationnship have been studied too. In the seismic exploration, the physical properties of the rocks are studied by the artificial mechanical vibration of the medium when the seismic wave propagats. The anisotropic medium namely transverse isotropic media exists widely in the lithosphere. The finite difference formula,describing the movement of the elastic medium, has been established from the broad Hooker law.and the seismic illumination simulation with finite difference operators began laterly.ln this text,it is concluded that it is very helpful to improve the field exploration by simulating the illumination of the compress waves and shear waves (it refers to convert sv waves here).The seismic illumination can simulate the field seismic exploration collecting methods, optimize the designation of the system, so it can reduce the risk of investment and improve the economic benefit. Therefore, it are used as a kind of evaluation methods of field collection usually. The seismic illumination are influenced by the seismic exploration gathering parameters.such as the source、the arrangement of receiving mode、the distance between the recevers and the subsurface geologic structure.Firstly,the ray tracing was used in the seismic research method for the illumination.and this kind of method works well in the horizontal layer structure of geological model, but does bad in the complicated geological model due to the defects of ray tracing law itself. Because of adapting to the complicated geological model, the wave equation method can provide more information to study of the medium physical parameter in the wave field. By establishing the complicated geological model and underground concealed deposits of oil and gas with differrent geological environment, we can obtain the conclusion of the illumination, optimizing the acquisition method, increasing explorat-ion precision.So we can establish the optimizated acquisition system based on exploration targets truly,with which to improve the economic benefit with theoretical guidance and technical support.The seismic denoising technology is important in the process of the seismic exploration, it plays an important role to obtain the true imaging underground geologic structure, especially in the complicated geological conditions,the influence of the long wavelength and the short wavelength statics problem is important in the process of the seismic data.In this thesis,I have gotten the achievements in studing the seismic illumination and processing the seismic data under the complex geological conditions and the experience to study of the complex ge-ological region.更多还原