Azimuthal Prestack Seismic Inversion for Fracture Parameters Based on L1–2 Norm Regularization

The inversion of fracture parameters, using the variation in prestack seismic amplitude with incident angle and azimuth (AVAZ), is a primary method for predicting subsurface fractures. However, the inversion for fracture parameter is inherently ill-posed, necessitating the integration of regularization constraints, such as the L1–2 norm, to enhance inversion accuracy. In this article, we hypothesize that the fractured reservoir exhibits horizontal transverse isotropy (HTI) and model it accordingly. Under this premise, we convolve the PP-wave reflection coefficient in HTI media, characterized by fracture parameters, with the seismic wavelet to establish a forward model. Subsequently, leveraging the Bayesian framework and assuming seismic noise follows a Gaussian distribution, and we introduce the L1–2 norm as a prior distribution model to constrain azimuthal prestack seismic inversion. To address the issue of insufficient lateral continuity in the inversion, we incorporate low-frequency information as a constraint in objective function formulation. Finally, we use the alternating direction method of multipliers (ADMM) to efficiently solve the objective function. The proposed method is validated through both synthetic and real datasets, demonstrating its efficacy in mitigating ill-posedness of fracture parameter inversion and enhancing inversion accuracy.