东营凹陷盐膏层的重震联合解释技术

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1 700~3 700 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。

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

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 salt-gypsum 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.