Spectral inversion algorithm based on compressive sensing and its applications while drilling

In the process of deep water drilling, the key strata, especially weak layers (formation with low tensile strength) under ultra-high temperature and pressure environment are big problems. What's more, the lack of accurate and rapid identified technology against offshore ultra-high temperature and pressure weak layers has led to frequent drilling accidents, which is an important problem to be solved in offshore ultra-high temperature and pressure oil and gas exploration and development. The application of high-precision seismic data, as a real-time monitoring basic data while drilling, can effectively provide detailed geological structure information ahead of the bit. Based on the spectral inversion technology to enhance resolution, this paper proposes a spectral inversion algorithm via compressive sensing L0 norm algorithm, and form a complete technical process workflow to enhance resolution. This method can realize effective extension frequency of seismic data with relative amplitude preservation and fidelity, in order to identify weak layers and realize comprehensive prediction of high precision key layers by seismic data processing and analysis while drilling. Application of actual data in the deep layer of the West South China Sea oilfield, this method effectively identifies key information such as weak layers, key formations, and reservoir depth ahead of the bit. The results were consistent with the logging data after drilling, which verified the effectiveness of the method and provided a basis for the risk assessment of ultra-high temperature and pressure drilling in the western South China Sea oilfield.