地震沉积学探讨

The Discussion of Seismic Sedimentology

地震沉积学是用地震手段研究沉积岩及其形成过程的学科,其研究手段主要有90°相位转换和地层切片技术等。90°相位转换使地震相位具有了岩性地层意义,可以用于高频层序地层的解释;地层切片是指对某一层位内进行等比例内插切片之后用来研究各个等时地层单元的沉积体系(相)的平面展布。文章认为:①由于受地震分辨率的限制,地震沉积学目前主要应用于研究宏观的地层、岩石、沉积史和沉积体系,还没有达到全面研究沉积岩及其形成过程的程度,因此,目前的地震沉积学是利用地震手段结合井资料研究宏观的地层、岩石、沉积史和沉积体系的一门学科,它还需要进一步的发展才有可能继地震地层学、层序地层学之后真正成为一门研究沉积岩及其形成过程的新学科;②相位转换技术中转换的角度并不一定局限于90,°可以是其它角度的相位转换,这要根据层位标定的具体情况而定;③地层切片比时间切片和沿层切片更加合理,但是目前的地层切片技术还没有考虑地层的沉积速率随时间的变化,因此,地层切片还不是严格意义上等时的。

Seismic sedimentology is the use of seismic data in the study of sedimentary rocks and the processes by which they were formed. The key technology includes ： ninety-degree phasing of seismic data and stratal slicing etc. The technology of ninety-degree phasing of seismic data gives lithological meaning to seismic phase and can be used in high frequency sequence interpretation ; the technology of stratal slicing can be used to study the planar distribution of isochronal depositional systems by using a kind of slice named ＂stratal slice＂. To make the stratal slice, a series of surfaces are firstly inserted between two isochronal depositional surfaces and then slices are made along each of them. Ideas in this paper is that ： （ 1 ） At present , seismic sedimentology is only used in the research of macroscopic formation, rock, depositional history and depositional systerm because of the limit of seismic resolution. It still can not reach the research of sedimemtory rocks and the process in which they were formed. Therefore, seismic sedimentology at present is a subject to study macroscopic formation, rocks, depositional history and depositional systerm with seismic and well logging data using the geophysical technologies. It still needs a further development to be a new subject like seismic stratigraphy and sequence stratigraphy which are used to study the sedimentary rocks and sedimentary process. （2） In the use of the phasing technology, the phase-adjust angle shouldt be limited to 90 degrees and it should be determined in the well log-seismic data calibration. （3） Strata slice is more perfect than time slice and horizontal slice, but at present, the alteration of deposition rate versus time is ignored in the strata slice technology. Therefore, strata slice is not strictiy along the isochronal surfaces.