应用高分辨率地震技术识别下切谷--松辽盆地杏树岗泉头组解释实例

Application of high resolution seismic technique in recognizing incised valley,an interpretation case study for Quantou Formation in Xinshugang area,Songliao Basin

下切谷的下切与沉积作用通常造成与下伏地层呈不整合接触关系,且形成独特的几何外形和充填特征。基于宽频带高分辨率三维地震资料,本文在松辽盆地北部杏树岗地区泉头组地层中识别出下切谷,在探讨典型下切谷地震反射的几何结构特征和频率振幅特征基础上,通过井震对比、三维地震精细解释及三维可视化分析,预测了泉头组下切谷发育带,为该区确定层序界面及其性质提供了依据。该区下切谷沉积层为低位域晚期碎屑沉积物,其内部河道砂储层较发育;下切谷不整合面是油气横向运移的有利通道,其中河道砂是油气运移和聚集的重要场所。

The incision and deposition of the incised valley often cause unconformity contact with the underlying strata,forming a unique geometric shape and filling characteristics.Based on the 3D seismic data with wide frequency band and high-resolution,the incised valley of the Quantou Formation in Xingshugang area in the Northern Songliao Basin was recognized in this paper,after discussing the geometrical structure and frequency amplitude characteristics of the seismic reflection from the typical incised valley,the incised valley development zone in the Quantou Formation was predicted through well-seismic correlation,3D seismic fine interpretation and 3D visualization analysis,providing foundation for determining sequence boundary and their properties.The study results showed that the incised valley sediments are the clastic sediments at low-stand and late period The channel sand reservoir inside the incised valley are relatively developed,and the unconformity surface of the incised valley is the favorable pathway for oil and gas migration,so the channel sands inside the incised valley are the main place for the migration and accumulation of oil and gas.