基于TK能量的峰值频率在沉积旋回划分中的应用

Sedimentary cycle division using peak frequency of time-frequency Teager-Kaiser energy

沉积旋回分析在地层学理论研究和石油勘探开发中起着重要的作用。依据测井曲线的形态定性划分是常规的沉积旋回划分方法,在井点位置处这种旋回划分较为准确,但在无井之处的沉积旋回划分则主要依靠地质认识,具有较强的主观性。地震资料中蕴含了丰富的与沉积旋回有关的信息,利用其时频属性曲线可以进行沉积旋回划分。本文选用具有较好时频分辨能力的广义S变换方法计算时频属性曲线,并将该方法应用于正旋回、反旋回、正反旋回以及反正旋回四种沉积旋回模型,模型的旋回划分结果验证了时频谱峰值频率属性进行沉积旋回划分的有效性;但在实际地震资料应用中,时频谱的时间分辨率不高。基于时频谱的Teager-Kaiser能量谱,提高了时频分析结果的时间定位性和聚焦性,基于Teager-Kaiser能量谱属性的沉积旋回划分可以更好刻画地质结构的变化和薄互层结构。将该方法应用于新疆某油田侏罗系的沉积旋回划分,其划分结果与井资料的沉积旋回划分结果吻合较好,验证了方法的可靠性。

Sedimentary cycle analysis plays an important role in stratigraphic theory research and petroleum exploration and development.Qualitative division of logging curves is a conventional method for dividing sedimentary cycles,which is more accurate at wellbore locations,but the division of sedimentary cycles in non-wellbore locations mainly depends on geological knowledge and has strong subjectivity.Seismic data contain abundant information related to sedimentary cycles.Sedimentaiy cycles can be divided by using time-frequency attribute curves.In this paper,the generalized S-transform method with better time-frequency resolution is used to calculate the time-frequency attribute curve,and the method is applied to four sedimentary cycle models:normal cycle,inverse cycle,normal-inverse cycle and inverse-normal cycle.The results of cycles division of the model validate the validity of the peak frequency attributes of timefrequency spectrum in the division of sedimentary cycles;However,in the practical application of seismic data,the time resolution of time-frequency spectrum is not high.Teager-Kaiser energy spectrum based on time-frequency spectrum improves the time positioning and focusing of time-frequency analysis results.The division of sedimentary cycles based on Teager-Kaiser energy spectrum attributes can better-depict the changes of geological structure and thin inter-bedded structure.The method is applied to the Jurassic sedimentary cycle division of an oil field in Xinjiang.The results of the division are in good agreement with those of the well data,which verifies the reliability of the method.