东营凹陷盐膏层的重震联合解释技术

A method to inverse salt-gypsum strata by jointing gravity-magnetic and seismic data in Dongying sag

用单一的物探方法难以探测沉积盆地中的盐膏层,为此提出了基于重力'剥皮'的变密度多界面重磁震联合解释技术.首先利用地震、钻井确定的第三系深度和重力反演的中生界、奥陶系、太古界深度,采用重力'剥皮'技术获得由盐膏层引起的剩余异常,据此反演得到了东营凹陷的盐膏层的顶面深度和等效厚度.反演结果表明,东营凹陷盐膏层主要由10个规模较大的盐膏体组成,呈北东向的扇状展布,顶面深度在1 700～3700 m,北部埋深较大,南部埋深较小.与钻遇盐膏层的25口钻井资料对比,反演误差仅为2.96%,说明利用重磁震联合解释技术反演盐膏层是一项可行的技术.

It is difficult to inverse salt-gypsum strata in deposit basin only using one geophysical method. Based on gravity “barking method”, a method of jointing gravity-magnetic and seismic data was presented for variational density multi-interfaces inversion. First based on the depth of Tertiary getting from seismic and bores and the depth of Mesozoil, Ordovician system and Archean by gravity inversion, the residual anomaly of salt-gypsum strata was calculated by gravity “barking method”. Then the depth and equivalent thickness were inversed. The results show the salt-gypsum strata in Dongying sag are mainly made up of ten big salt-gypsum bodies, which are fan-shaped tend to northeast （NE）. The depth range of saltgypsum strata is from 1700 to 3700 m. It is deeper on the north and shallower on the south. The inverse error is only 2.96% compared with the data of 25 bores drilling through salt-gypsum strata. It is shown that the interpretation method by jointing gravity-magnetic and seismic data is effective to inverse salt-gypsum stratum.