苏丹Muglad盆地Fula坳陷白垩系Abu Gabra组地震相研究

Seismic facies of the Cretaceous Abu Gabra Formation in Fula Depression,Muglad Basin,Sudan

李德江 朱筱敏 杨俊生

Li Dejiang Zhu Xiaomin Yang Junsheng

研究认为,Fula坳陷白垩系Abu Gabra组可划分为7个三级层序。根据地震反射参数,从内部反射结构和外部几何形态出发,在Abu Gabra组的地震反射剖面上识别出杂乱相、平行亚平行席状相、前积楔状相、前积(楔状)充填相、上超充填相。根据连续性和振幅等辅助参数可以将上述地震相进行细分,共计有主要地震相9种,分别为强振幅-好连续平行席状相,中、强振幅-中、好连续-平行-席状相,中振幅-中、差连续-亚平行席状相,中振幅-中、好连续-亚平行席状相,中、强振幅-中连续-楔状-充填相,中振幅-中、差连续-楔状-充填相,中振幅-中、差连续-上超-充填相,中振幅-中等连续-前积-楔状相,中振幅-差连续-杂乱相。这些地震相在平面上分布部位明确,纵向上具有继承性和差异性。地震相在空间上的分布与凹陷结构及构造演化有良好的对应性。

The Cretaceous Gabra Formation in the Fula Depression,Muglad basin,Sudan,can be classified into seven three-order sequences.Based on the seismic reflection parameters,internal reflection configuration and external shape,five types of seismic facies are identified on the seismic reflection profiles of the Abu Gabra Formation.They are chaotic facies,paralleling and sub-paralleling sheet facies,foreset wedge facies,foreset(wedge)-filling faceis,and onlap-filling faceis.These facies may be further subdivided into nine classes in terms of their amplitudes and continuities,i.e.(1)parallel sheet facies with strong amplitude and high continuity,(2)parallel sheet facies with medium-strong amplitude and moderate-high continuity(3)sub-parallel sheet facies with me-dium amplitude and moderate-poor continuity,(4)sub-parallel sheet facies with medium amplitude and moderate-high continuity,(5)wedge-filling facies with medium-strong amplitude and moderate continuity,(6)wedge-fil-ling facies with medium amplitude and moderate-poor continuity,(7)onlap-filling facies with medium amplitude and moderate-poor continuity,(8)foreset-wedge facies with medium amplitude and moderate continuity,and(9)chaotic facies with medium amplitude and poor continuity.These seismic facies distinguish from one another ho-rizontally but show hereditability and differentiation over vertical sections.The spacial distribution of the seismic facies corresponds well with the structure and tectonic evolution of Fula depression.

10.11743/ogg20070107