川东大猫坪地区长兴组生物礁储集层预测

Prediction of Reef Reservoir in Changxing Formation of Damaoping Area,Eastern Sichuan Basin

四川盆地东部大猫坪地区上二叠统长兴组生物礁呈环带状分布,单个生物礁规模小且埋藏深,纵向上多期次叠置,其储集层非均质性强,预测难度较大。针对生物礁储集层内部地震波同相轴振幅偏弱、反射空白和杂乱的特点,在井震标定和正演模型建立生物礁地震响应特征基础之上,通过聚类分析对礁体敏感的多种地震属性融合波形,预测生物礁分布,以过生物礁的等时地震振幅切片为约束,利用基于S变换的频谱分解振幅切片识别生物礁边界。分频与波形聚类组合方法识别的生物礁边界更为准确,得到的生物礁内部特征更加精细,与研究区钻井结果符合程度高。

The reefs of the Upper Permian Changxing formation in the Damaoping area of the eastern Sichuan basin are distributed in the shape of ring and strip.Individual reefs are characterized by small scale,deep burial depth,multiple periods of vertical superimposition and strong heterogeneity,leading to difficulties in reef prediction.Regarding the characteristics of weak amplitude of in phase axis,blank and disordered reflections within the reef reservoir,and based on the logging seismic calibration and forward models to establish seismic re sponse characteristics of the reef,clustering analysis is performed to fuse multiple seismic attributes which are sensitive to reef,and the reef distribution is predicted.Constrained by isochronal seismic amplitude slice through reefs,S transformation based spectrum decomposi tion amplitude slices are used to identify reef boundary.The combined method of fractional frequency and waveform clustering can get more accurate reef boundary and more detailed characteristics of the reef,which are highly consistent with the actual drilling results in the study area.