地震地貌分析技术及其在哥伦比亚亚诺斯盆地的应用

Seismic geomorphology analysis and its application in Llanos Basin,Columbia

在哥伦比亚亚诺斯盆地X区块的地震层序研究过程中,笔者发现等时地震地层切片清晰的成像效果可以对孤立的切片影像中的古地貌及古沉积环境有很好的刻画.工区目的层的辫状河三角洲前缘、前三角洲等沉积特征在地震地层切片中清晰可见.更重要的是,在地质时间域内,通过连续的古地貌和古沉积环境分析,可以反推出地层的层序界面和体系域界面,甚至在体系域内还可以划分识别更小的地层单元及其界面,并在此基础上划分更高分辨率的地震层序.经钻井划分的沉积相与层序格架的校验,二者吻合程度高.这种逆向倒推的研究方法为更高精度的地震层序研究提供了借鉴,探索出了一条在无井和少井地区识别层序界面,建立地层层序格架的新思路.

Through the study on seismic sequences of X survey in Llanos Basin, Columbia, the authors found the clear images in strata slices can make the paleo-geomorphology and paleo-sedimentary environment be characterized distinctively. In the target interval of the study area, sedimentary characteristics of delta front and prodelta were determined in the slices clearly. More importantly, within the geological time, the sequence boundaries could be figured out reversely though the continuous paleo-geomorphology and paleo-sedimentary environment analysis. Furthermore, we could even identify the boundaries of the smaller geology units and the seismic sequences with a higher resolution. These results have well matched the sedimentary facies and sequence framework constructed by the wells. This back stepping method has provided a reference for the seismic sequence research at a higher resolution, especially in the areas that lacked the well data.