Seismic Q estimation by combinations of frequency statistics attributes
Zhao Ning1, Cao Siyuan1,5, Wang Zongjun2, Zhu Lianfeng3, Bai Lina4, Hu Yanfang1, Zhang Haoran1
1. State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum Beijing),Beijing 102249,China;
2. CNOOC Research Institute,Beijing 100027,China;
3. China Petroleum Greatwall Drilling Company(GWDC
Abstract：The quality factor Q is a main parameter of the characterization of the stratum absorption and attenuation characteristics.The accuracy value of Q has practical significance function to predict concealed lithological gas.We propose a Q estimation approach by combinations of statistical frequency attributes.Considering the amplitude attenuation law in frequency domain,exponential decay term is obtained with Taylor approximate expansion.Then a new method for calculating Q with N-order approximation based on frequency attributes is proposed.According to model tests,2-order approximation offers a high accuracy while there is a certain error with 1-order approximation.Based on the error factor analysis,multi interval fitting formula is proposed as a newer method to improve precision of Q.Due to the stability of the statistical properties,the method based on attribute combination for extracting the Q value is more stable than other methods.Our further study finds that the centroid frequency shift method is an approximate of 1-order approximation attribute combination.
