【作者】 张欣；

【导师】 杨国权；

【作者基本信息】 中国石油大学(华东) ， 地质资源与地质工程， 2017， 硕士

【摘要】 随着各大油田的发展以及对地下油气探测的难度的增加,对地下构造的探测目标从常规构造油气藏逐渐发展到对非常规油气藏以及岩性油气藏的探测。针对这些油气藏的成像需利用叠前深度偏移技术,而速度的准确度是正确成像的前提。现阶段在实际生产中应用很广的是层析速度反演方法,然而随着对油气藏勘探方法的要求越来越高,传统的反射波层析速度反演的弊端逐渐显露出来。本文在层析速度反演的框架内,针对传统成像域走时层析的不足,提出了成像域立体层析反演方法。首先,针对传统反射层析在低信噪比数据中同相轴拾取困难这一问题,重新定义了层析反演的数据空间和模型空间,即利用地震波走时,炮、检点位置以及炮、检点处射线出射方向同时约束速度模型来增强反演的稳定性和精度。第二,由于数据空间拾取的准确性是影响反演效果的最重要因素之一,因此本文提出在初始的成像域道集中进行剩余曲率与构造倾角的拾取,并运用特定的修正公式修正得到更为准确的立体层析数据空间。第三,根据射线扰动理论以及射线传播矩阵的性质,本文推导出成像域的立体层析核函数,使核函数在对地质体的覆盖效果更好的前提下,使反问题的求解具有更强的稳定性,从而获得更精确的速度反演结果。最后,利用对模型和实际资料的测试,证明了在成像域中进行立体层析速度反演,可以达到较高的反演精度。最后,在本文的最后一章中,通过对两种(数据域、成像域)立体层析反演方法的对比,以及成像域立体层析反演与成熟的成像域走时层析反演方法的对比,验证了成像域立体层析的优势,并说明了立体层析在解决实际问题时与实际地下情况的契合性与优越性。更多还原

【Abstract】 With the development of major oil fields and the difficulty of detecting the underground oil and gas.The exploration target for underground structure gradually developed from the conventional tectonic oil and gas reservoirs to the exploration of unconventional oil-gas reservoirs and lithologic oil-gas reservoir reservoirs.For the imaging of these reservoirs,the prestack depth migration technique is required,and the accuracy of the velocity is the premise of correct imaging.At this stage,the tomographic velocity inversion is widely used in the actual production.However,with the increasing demand for the exploration methods,the shortcomings of the traditional reflection tomography velocity inversion are gradually revealed.In this paper,the author proposed a method of stereo-tomography inversion to improve the shortcomings of traditional reflection tomography.Firstly,this method is proposed to solve the problem that it is difficult to pick events in low signal-to-noise ratio data with the traditional reflective tomography method.This method redefines the data space and model space of the tomography inversion,that is,utilizing the seismic travel time,source location,receiver location,and the ray direction of source and receiver simultaneously to constraint the velocity model to enhance the stability and accuracy of inversion.Secondly,the accuracy of the data space picking is one of the most important factors that affect the inversion effect.Therefore,this paper proposes a stereo-tomography velocity inversion method in image domain.We perform the pickup of the residual curvature and structural dip on initial gathers in imaging domain,and use specific correction formula to obtain a more accurate stereo-tomography data space.Thirdly,based on the theory of ray perturbation and the properties of propagation matrix,this paper derives the kernel function of stereo tomography in imaging domain,which makes equation solving process more stable under the premise of better coverage on geological body,and thus obtains more accurate speed inversion results.And,through test on model and actual data,we prove that performing stereo tomographic velocity inversion in imaging domain can achieve high inversion accuracy.Finally,in the last chapter of this paper,through the comparison of two methods of stereo tomographic method(data domain and imaging domain),as well as stereo tomographic method in imaging domain and mature travel time tomographic inversion in imaging domain,we prove the advantages of stereo tomographic method in imaging domain,and demonstrate the superiority and correspondence of stereo tomographic method in solving the practical problems.更多还原