松辽盆地梨树断陷苏家屯地区火石岭组—营城组地震相与沉积相

Seismic facies and sedimentary facies of Huoshiling Formation-Yingcheng Formation in Sujiatun Region,Lishu Fault Depression,Songliao Basin

根据岩心观察、测井、录井、三维地震资料及地震沉积学分析,研究梨树断陷苏家屯地区火石岭组—营城组层序地层、地震相特征及其沉积解释。结果表明:研究区火石岭组—营城组可划分为SQ1—SQ5五个三级层序;沉积相类型主要有扇三角洲、正常三角洲、湖泊和火山岩沉积;火石岭组—营城组地震相外部可划分为前积地震相、杂乱地震相、席状平行—亚平行地震相、发散地震相及条带状地震相五大类,可细分为十一小类;根据剖面地震相—沉积相分析,并结合平面地震相、均方根振幅属性,研究区SQ1时期主要发育火山岩沉积,SQ2、SQ3时期扇三角洲广泛分布,主要发育在东部断阶带和西部断阶带的缓坡区,以及桑树台断裂和曲家断裂的陡坡区,湖泊相主要分布在中央深断带内。随着盆地扩张,SQ4、SQ5时期主要发育正常三角洲,湖泊相范围扩大。该结果可为研究区火石岭组—营城组油气勘探提供地质依据。

According to core observation,well logging,3D seismic data and seismic sedimentology analysis,the sequence stratigraphy,seismic facies and sedimentary interpretation of the Huoshiling Formation-Yingcheng Formation in Sujiatun Region,Lishu Fault Depression are studied.The results show that the Huoshiling Formation-Yingcheng Formation can be divided into 5 third-order sequences,SQ1 SQ5,and its sedimentary facies mainly include fan delta,normal fan delta,lacustrine deposits and volcanic deposits.Five types of seismic facies,including foreset pattern,chaotic pattern,sheet parallel-subparallel pattern,divergent pattern and banded reflection pattern,were recognized according to the external and internal reflection configurations.Some categories can be further divided into eleven subtypes by different parameters.Moreover,according to the sedimentary interpretation of seismic profiles and the comprehensive analysis of the horizontal distributions of seismic facies and RMS amplitude,it is believed that the study area mainly develops volcanic deposits in SQ1;fan delta is widely developed in gentle slope of the eastern and western step-fault zone and steep slope of Sangshutai Fault and Qujia Fault,lacustrine facies is locally distributed in the deep faulted belt in SQ2 and SQ3;with the expansion of the basin,the study area is gradually dominated by normal fan delta and lacustrine facies is further expanded in SQ4 and SQ5.These research results provide a geological basis for exploration of Huoshiling Formation-Yingcheng Formation in the study area.