Xinjiang Petroleum Geology ›› 2020, Vol. 41 ›› Issue (4): 471-476.doi: 10.7657/XJPG20200413

• APPLICATION OF TECHNOLOGY • Previous Articles     Next Articles

Decomposition and Application of Constrained Sparse Inversion Spectrum Based on ISTA Algorithm

GAO Qiuju1a(), ZHANG Yunyin1b, QU Zhipeng1a, XU Yankai2(), WANG Zongjia1a, WANG Qianjun1b   

  1. 1. Sinopec Shengli Oilfield Company, a.Institute of Geophysics; b.Research Institute of Exploration and Development, Dongying, Shandong 257000, China;
    2. School of Geosciences and Information Engineering, China University of Petroleum, Beijing 102249, China
  • Received:2019-04-15 Revised:2019-10-31 Online:2020-08-01 Published:2020-08-05
  • Contact: XU Yankai E-mail:527266669@qq.com;xuyk163@163.com

Abstract:

The resolution of conventional spectral decomposition can’t meet the needs of seismic interpretation, which can be well solved by the spectral decomposition of constrained sparse inversion. In this method, seismic signal is regarded as the convolution of known wavelet matrix library and pseudo-reflection coefficient, then the spectral decomposition is transformed into an inverse problem which focuses on how to obtain an optimum solution. The L2 norm regularized by L1 norm is used as the objective function for the constrained sparse inversion spectrum decomposition, then the iterative threshold algorithm is used to obtain the solution of the inverse problem. In order to improve the calculation speed of spectral decomposition, a new kind of operator is established on the basis of Ricker wavelet and the optimal solution can be obtained by ISTA algorithm. Based on which, the spectral decomposition of constrained sparse inversion is applied into numerical modeling and the results are compared with those of conventional spectral decomposition. The results show that the spectral decomposition of constrained sparse inversion has high time-frequency resolution. The actual application of the algorithm in the Wellblock Yi176 of Bonan sag in Jiyang depression indicates that the processing result is sensitive to oil and gas, which can be used to identify oil and gas reservoirs.

Key words: ISTA algorithm, constrained sparse inversion, spectral decomposition, continuous wavelet transform, hydrocarbon detection, L1 norm regularization, Ricker wavelet, low-frequency shadow

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