鄂尔多斯盆地高家河地区上古生界地震沉积学研究

综合利用地震岩性学理论、地震反射同相轴非频变特征、地震数值模拟和时频分析等方法对鄂尔多斯盆地高家河三维地震工区上古生界地层进行了地震沉积学研究。研究表明:①基于在上古生界建立的5个参考等时地震反射界面,通过线性内插,在90°相位地震数据体中形成311层具有等时意义的地层切片;②在地震薄层(<λ/4,λ为通过砂岩的地震波波长)的情况下,90°相位地震数据的极性与岩性具有对应关系,零相位和90°相位地震剖面具有相同的纵向分辨率;③利用振幅信息进行岩性(沉积体系)解释时,频率并不是越高越好；最佳频率是使目的层内最厚砂岩达到调谐振幅的频率(调谐频率);④90°相位地震数据的时频谱不能反映由薄砂层到厚砂层的连续变化特征,所以利用90°相位地震资料地层切片预测岩性时,必须将地震主频调整为最厚砂层的调谐频率。将上述认识应用到工区上古生界山西组二段最下部(P1S23)的地层研究,揭示了该时期主要水道的分布特征。

Seismic sedimentology study was carried out on the Upper Paleozoic of 3D seismic survey area at Gaojiahe Area in Erdos Basin using the frequency-independent event characteristic,seismic litholgoy theory,seismic numerical simulation and time-frequency analysis.The results indicate:①the five reference isochronous seismic reflection interfaces,established in Upper Paleozoic,have formed 311 strata slices with isochronous meaning in 90° phase seismic data volume by linear interpolation;②when the layer is thin (<λ/4，λ means seismic wavelet length),the polarity of 90° phase seismic data corresponds with lithology,and the seismic sections of zero-phase and 90° phase own the same longitudinal resolution;③when the amplitude is utilized for lithology (sedimentary system) interpretation,the optimal frequency is the tuning frequency which makes the thickest sandstone reaching tuning amplitude;④the time-frequency spectrum of 90° phase seismic data cannot reflect the continuous variation characteristics from thin sandstone to thick sandstone.The above recognitions are applied on P1S23 formation of the Upper Paleozoic at Gaojiahe Area  in Erdos Basin,and the distribution of the main channels was revealed.

国家自然科学基金(41372118)及陕西省科技计划(2014K10-12)项目资助。