多子波分解技术在T2屏蔽下薄砂岩储层预测中的应用  

Application of Multi-wavelet Decomposition Technique to Thin Sandstone Reservoirs Prediction under T2 Shielding

作　　者：徐立显[1] Xu Lixian(Research Institute of Petroleum Exploration and Development,Daqing Oilfield Co.,Ltd.,Daqing Heilongjiang 163712)

机构地区：[1]大庆油田勘探开发研究院,黑龙江大庆163712

出　　处：《中外能源》2021年第12期43-47,共5页Sino-Global Energy

摘　　要：松辽盆地北部泉四段F11油层组泥岩与上覆青山口组一段泥岩存在巨大的波阻抗差,导致扶余油层顶面的地震反射同相轴(T2)表现为低频的强振幅特征。受此影响,扶余油层上部F11油层组内砂岩的地震反射特征完全被掩盖在T2强轴里,应用常规地震属性预测砂岩难度大。目前常规地震资料处理中所用的方法都是假设地震波不会随着传播距离的变化而变化,但这种假设与真实情况差别较大,有时还会出现造成储层预测的失误。为提高储层钻井的成功率,须从根本上改进这种单一子波假设的地震模型,因此产生了基于多子波地震道模型的子波分解与重构技术。本文通过正演模型和松辽盆地三肇地区扶余油层实例研究认为,多子波分解与重构技术克服了T2屏蔽的影响,能够较好地预测F11油层组内的薄砂岩储层的分布,使F11油层组内砂岩预测的符合率由60%提高到80%,大大提高了钻井成功率。因此,地震子波分解与重构技术能够为强屏蔽下的薄砂岩储层预测提供一种有效的手段。There is a huge impedance difference between the mudstones of F11 oil layer of K1q4 and the mudstones of overlying K1qn1 in the north of Songliao Basin,which leads to the seismic reflection event(T2)on the top surface of Fuyu reservoir showing the characteristics of low frequency and strong amplitude.Influ-enced by this,the seismic reflection characteristics of sandstones in F11 oil layer in the upper part of Fuyu reservoir are completely covered in T2 strong reflection,and it is difficult to predict sandstone distribution by using conventional seismic attributes.At present,the conventional seismic data processing methods assume that the seismic wave will not change with the change of propagation distance,but this assumption is quite different from the real situation,sometimes leading to reservoir prediction errors.If we want to improve the success rate of reservoir drilling,we must fundamentally improve the seismic model based on single wavelet assumption.Therefore,seismic wavelet decomposition and reconstruction technique based on multi-wavelet seismic trace model is adopted.Based on the forward modeling and the case study of Fuyu reservoir in Sanzhao area of Songliao Basin,this paper considers that the multi-wavelet decomposition and reconstruction technique over-comes the influence of T2 shielding,and can better predict the distribution of thin sandstone reservoirs in F11 oil layer,so that the coincidence rate of sandstone prediction in F11 oil layer increased from 60% to 80% and the success rate of drilling is greatly improved.Therefore,the seismic wavelet decomposition and reconstruction technique can provide an effective means for thin sandstone reservoir prediction under strong shielding.

关 键 词：多子波分解 不同主频 子波重构 T2屏蔽 薄砂岩 

分 类 号：P618.13[天文地球—矿床学]