三角网格参数化在反射地震走时层析成像中的应用

Application of Triangle Cell Parameterization in Travel-time Tomography of Reflection Seismic Data

矩形网格参数化是反射地震走时层析成像中的传统参数化方式,然而这种参数化方式本身的缺点(如剖分的灵活性差,对速度界面的描述精度差)却在层析成像的正反演过程中产生了很多不利因素:正演模拟和层析反演时存储量大、计算量大、计算耗时久,层析反演的方程性态差、求解难度高等。鉴于矩形网格参数化层析成像的上述缺点,将三角网格参数化应用到反射地震走时层析成像中,研究发现三角网格参数化本身的优点(如剖分的灵活性强,对速度界面的描述精度高)在层析成像的正反演过程中产生了诸多有利因素,大大减少了网格的数目,在正演模拟和层析反演时大大减少了存储量、计算量和计算时间,并改善了层析反演的方程性态,降低了求解难度。因此,三角网格参数化与矩形网格参数化相比在反射地震走时层析成像中更有优越性,模型试验表明两种参数化方式得到的层析反演结果具有可比性。

The rectangle cell parameterization is a traditional cell parameterization style in travel-time tomography of reflection seismic data, which show many shortcomings, such as poor dividing flexibility and low accuracy in describing the reflection interface, It can cause large storage and calculation amount, long calculation time , poor equation status and increased difficulty in solving the equation to use this method in modeling and inversion process. The triangle cell parameterization has many merits compared to rectangle cell parameterization. It shows strong dividing flexibility, high accuracy in describing the reflection interface and decreased amount of cells, and can reduce storage and calculation amount, shorten calculation time in modeling and inversion process, and modified equation status and decreased solving difficulty in inversion process. Thus the triangle cell parameterization is better than the rectangle cell parameterization for travel-time tomography of reflection seismic data. Model test shows that the results obtained by two parameterization styles are comparable.