对数谱根式法Q值反演  

Seismic Q estimation with logarithmic spectrum equation root

作　　者：曹思远[1] 谭佳 高明 袁殿 杨金浩 张浩然[1] 

机构地区：[1]中国石油大学北京CNPC物探重点实验室,北京102249 [2]I中国石油新疆油田分公司勘探开发研究院地球物理研究所,新疆乌鲁木齐830013

出　　处：《石油地球物理勘探》2014年第1期161-166,共6页Oil Geophysical Prospecting

基　　金：国家重大专项子课题(2011ZX05024-001-01);国家自然科学基金项目(41140033)联合资助

摘　　要：品质因子Q值是表征地下介质对地震波吸收衰减特性的一个重要参量,不仅反映介质的内部本质特征,同时也是油气识别的重要指示因子,因此准确估算Q值对储层预测具有一定的意义。一般地,频率域提取Q值的方法较稳定,常用的有谱比法和质心频移法。谱比法具有较高的理论精度,但受信噪比影响较大,稳定性低;质心频移法的抗噪性较好,但存在理论近似,误差分析较困难。综合上述两种方法的优点,根据子波振幅对数谱上的衰减规律,提出了一种基于对数谱统计量组合的Q值反演法——统计属性组合法。在此基础上,通过对频率的积分提出了积分方程根式法。模型资料试算表明,统计属性组合法的理论计算精度较高,规避了质心法对震源谱的假设;积分方程根式法融合了谱比法和质心法的优点,其精度和抗噪性均比后二者高。Quality factor Qis an important parameter, one of characteristics of subsurface medium absorption of seismic wave.Qdescribes internal essential characteristics of the media,and is also an indication factor of oil and gas recognition.Therefore the accurate determination of seismic Q has certain significance to reservoir prediction.In general,it is stable to extract Qin the frequency domain,and the commonly used methods include spectral ratio and centroid frequency shift.Although the spectral ratio method has a higher theoretical precision,but it is vulnerable by the influence of SNR and has lack of stability.On the contrary,the centroid frequency shift method has higher robustness.But this method needs to do theoretical approximations,and it is difficult to do error analysis.So we present in this paper an inversion method based on statistical combination oflogarithmic spectrum to calculate Q according to natural logarithmic spectrum of the wavelet amplitude attenuation law in the strata.Based on this combination method of statistical properties,we propose logarithmic spectrum equation root method by integral for frequency.According to computations on model data,the combination of statistical properties has higher theoretical precision,and avoids the assumption of source spectrum using in the centroid frequency method;the logarithmic spectrum equation root method combines the advantages of the spectral ratio method and the centroid frequency method;and the accuracy and denoise are much higher than spectral ratio and centroid frequency.

关 键 词：品质因子Q 属性组合 根式法 抗噪性 

分 类 号：P631[天文地球—地质矿产勘探]