松辽盆地徐家围子断陷沙河子组地震相研究

STUDY ON THE SEISMIC FACIES OF THE SHAHEZI FORMATION IN XUJIAWEIZI FAULT DEPRESSION IN SONGLIAO BASIN

松辽盆地徐家围子断陷沙河子组处于断陷早期,受断陷影响较大.针对研究区的实际情况,根据地震反射终止关系,将沙河子组划分出了5个地震层序,即Sq1～Sq5.利用地震反射的内部结构和外部几何形态,结合地震同相轴等各类参数,在目的层内识别出楔状发散、席状平行、席状披盖、丘状前积、丘状空白和丘形乱岗状6种地震相,并描述其特征.通过综合解释,把地震相转换为沉积相.结果表明,沙河子组主要发育有辫状河三角洲、扇三角洲、湖泊和湖底扇等沉积体系.

The Shahezi Formation in the Xujiaweizi Depression in Songliao Basin,formed in the early stage of depression,is largely influenced by the depression.For the situation of less drilling and uneven distribution,based on the seismic reflection termination relationship,the Shahezi Formation is divided into five seismic sequences from Sq1 to Sq5.According to the internal reflection texture and external geometric configuration and in combination with parameters,six seismic facies are identified in the target sequences of the study area,including wedge shaped,parallel sheet,overlap,mound shape,blank and hummocky seismic facies,with detail descriptions of their characteristics.The seismic facies are transformed into sedimentary facies through a comprehensive interpretation.The results show that the target sequences develop the sedimentary systems of braided river delta,fan delta,lake and sublacustrine fan.