摘要
准噶尔盆地侏罗系Ⅲ层序底界面结构主要有发育底砾岩的不整合型、发育风化壳的假整合型和具明显沉积型式变化的整合型等 3类。在侏罗系Ⅲ层序底界面上、下延 4 0ms的波形地震相中 ,1～ 2类高频波形对应砂泥岩互层沉积 ;5～ 6类低频波形对应大套砂岩沉积 ;3～ 4类波形介于二者之间。地震波的振幅与界面上的岩石组合有关 ,中强振幅对应于砂、泥岩组合以及砾岩、粉砂岩组合 ,弱振幅对应于大套砂岩组合 ,中振幅介于二者之间。另外 ,低频波和中强振幅与地震前积反射有较好的对应关系。通过波形地震相、振幅以及反射结构的综合分析 ,认为玛湖西北斜坡和腹部的石南 -莫北地区有大面积的砂体分布 ,其中 ,车 -拐水下扇、玛湖辫状三角洲、中拐曲流河三角洲及石南 -夏盐曲流河三角洲等砂体发育区是有利的非构造圈闭发育区 。
The bottom boundary (interface) of Ⅲ sequence of Jurassic in Junggar basin could be chiefly divided into following three types in structure:(1).unconformity with basal conglomerate;(2).pseudo-conformity with weathered layer;(3).conformity with apparent variation in sedimentary type etc.In the waveform seismic phase of 40ms extension upwards and downwards in the bottom boundary of Ⅲ sequence of Jurassic,high frequency of waveform seismic type I-Ⅱ corresponds to sediments of sandstone layered with mudstone;Low frequency of type V-VI is in correspondence with large complete set of sandstone sediments while type Ⅲ-IV waveform is in between above two types.The amplitude of seismic wave is connected with rock assemblage on the bottom boundary,the medium stronger amplitude corresponds to the sand-mudstone assemblage as well as to the assemblages of conglomerate and silt rock,the weaker amplitude is in correspondence with the large complete set of sandstone assemblage while the medium intensity of amplitude is in between above two assemblages.Moreover,the low frequency seismic wave and the medium-stronger amplitude have a good correspondence with the progradational reflection of seismic.It is believed that,by a comprehensive analysis of waveform seismic phase,the amplitude and the reflection structure,the widespread of sandbodies in large area of northwestern slopes of Mahu Lake and Shinan-Mobei region in the central part,of which sandbodies of underwater fan of Che-Guai,Mahu braided delta,delta of Zhongguai meandering river and Shinan-Xiayan meandering river delta are well-developed and are favorable for forming nonstructural traps and have good potential for prospecting hydrocarbon.
出处
《石油与天然气地质》
EI
CAS
CSCD
北大核心
2002年第2期145-149,共5页
Oil & Gas Geology
关键词
Ⅲ层序
坡折带
地震相
砂体预测
有利区评价
sequence
topographic break zone
seismic phase
sandbody
prediction
evaluation
