浊积砂岩透镜体的地震判据和定量解释

在地震资料宽高频保持振幅处理的基础上,对穿过王50浊积砂岩透镜体地震剖面所进行的地震地层解释表明,与三角洲沉积伴生的浊积砂岩透镜体,位于三角洲前积斜反射的倾没部位,在该部位变得平缓的局部短反射段,是浊积砂岩透镜体的直接反映。结合钻井资料,对浊积砂岩透镜体再进行地震模型研究,根据地震模型给出的波形特征可定性圈定出砂岩体的边界。利用地震模型制作的定量解释图板,对地震剖面上的振幅进行定量解释,最后可编制出砂岩透镜体等厚图。但是,在对振幅定量解释之前,应从过井剖面出发,对所有地震剖面做空间振幅归一化处理。另外,由于王50浊积砂岩透镜体与嵌入泥岩中的典型楔形砂岩体不同,所以在定量解释图板中四分之一波长厚度上没有出现调谐引起的振幅极大化现象。

The seismic criteria of turbidite sand Lens and the quantitative interpretation

The stratigraphic interpretation of the seismic sections across Wang 50 turbidite lens，which were processed by relative amplitude preservation in high wide band, draws a conclusion that the turbidite sand lens associated with delta lies at the plunging part of oblique reflections from delta front，and is characterized by short gentle sloping reflections, The turbidite sand lens can be analysed by integrating the seismic modeling with drilling data.The boundary of the lens can be qualitatively located using the waveform characters shown by seismic modeling, Finally, the isopach map of the turbidite lens can be plotted by quantitatively interpreting the amplitudes on seismic sections using quantitative interpretation template made from seismic modeling, However, before the quantitative amplitude interpretation, the amplitude normalization of all seismic sections should be made starting from the section across well, Wang 50 turbidite sand lens is different from atypical sand wedge embeded in mudstone; therefore, no amplitude maximizing due to ‘tuning' occurs at 1/4 wavelength thickness on the quantitative interpretation template.