松辽盆地北部石炭—二叠纪地层厚度：来自深反射地震的证据

在松Ⅰ～松Ⅵ6条深反射地震剖面上依据震相特征并结合地质演化过程分析识别石炭—二叠系,分析其层位反射特征及同相轴特征,建立松辽盆地北部地区石炭—二叠系地震震相特征识别标志。主要震相特征为中—强反射能量,局部存在高值,整体同相轴连续—较连续,由南到北、由西向东规律变化。利用已有的钻遇石炭—二叠系的探井资料和地震波传播速度,得到研究区时间-深度转换关系。由研究区石炭—二叠系相位追踪对比后的反射时间分布,计算石炭—二叠纪地层顶界面与底界面在深反射地震时间剖面上的走时之差,通过时深转换得出研究区基底石炭—二叠纪地层厚度和分布。全区地层分布不很均匀,主要在中央隆起带以东地区及西部断陷区出现2个厚度高值区;地层整体由浅到深大致可分为上、中、下3层,且地震震相特征互不相同。松辽盆地北部石炭—二叠系分布对东北地区主力油层之下的深层油气勘探提供了有价值的依据。

Carboniferous-Permian stratigraphic thickness in northern Songliao Basin: Evidence from deep reflection seismic data

Based on the characteristics of the seismic phase on the section including the horizon reflection characteristics and the inphase axis characteristics and combined with the geological evolution process analysis, the authors established the seismic identification characteristics of the Carboniferous-Permian strata in the northern Songliao Basin. The Carboniferous-Permian strata were identified on six deep reflection seismic profiles of Song I-Song VI based on seismic phase characteristics. The main phase characteristics are medium-strong reflection energy, existence of local high values and the continuous overall in-phase axis changing from south to north and from west to east. The time-depth conversion relationship of the study area was obtained by collecting the exploration data of the existing Carboniferous-Permian strata and the seismic wave propagation velocity. Based on the reflection time distribution of the Carboniferous-Permian phase tracing correlation in the study area, the authors calculated the travel time difference between the top and bottom interfaces of the Carboniferous-Permian strata on the deep reflection seismic time profile, and gave the thickness and distribution of the Carboniferous-Permian strata in the study area by time-depth conversion. The distribution of the whole area is not extremely uniform. There are mainly two areas with high thickness, namely, the eastern part of the central uplift zone and the western part of the fault depression zone. The whole strata can be divided into upper, middle and lower layers from shallow part to deep part, and the seismic phase characteristics are different from each other. The distribution of Carboniferous-Permian strata in the northern Songliao Basin provides a valuable basis for deep oil and gas exploration under the main oil layers in Northeast China.