![]() ![]() ![]() 2019, 2021), such as imaging rough surfaces or complex media (Krebs et al. Recently, the least-squares reverse time migration (LSRTM) has been widely used in the field of seismic migration due to its ability to reduce the acquisition footprint and suppress imaging artifacts of reverse time migration (RTM) based on the two-way wave equation (Dai et al. 2016 Schwarz & Gajewski 2017 Bakhtiari Rad et al. The common reflection surface method, which uses multiple adjacent common-mid-points to realize multi-parameter stacking based on the paraxial ray theory, is another common method for separating and imaging diffraction waves in post-stack and pre-stack fields (Dell & Gajewski 2011 Huang et al. ( 1987), Claerbout ( 1992) and Fomel ( 2002) proposed an improved plane-wave destruction (PWD) filters and applied them to separate diffractions in dip angle gathers and synthesize plane-wave gathers (Taner et al. Kinematic differences between diffracted and reflected waves in a specific gather make it possible to separate diffracted waves. ![]() To overcome this problem, several methods have been proposed for separating and imaging diffraction waves. However, these small-scale diffractors carry key information about discontinuous structures in the subsurface, making the separation of diffracted waves crucial for characterizing diffracted targets. In traditional seismic data processing based on reflection waves, diffraction waves have low energy and amplitude that is one to two orders of magnitude weaker than reflection waves, and thus are difficult to use in imaging, resulting in their suppression as interference (Khaidukov et al. Conventional seismic processing techniques usuaptlly target reflection events, but seismic responses from small-scale diffractors, such as faults, cracks and caves, are usually represented as diffracted waves (Landa & Keydar 1998 Khaidukov et al. Seismic data are composed of reflected and diffracted information. Plane-wave least-squares migration, short-time ssa, diffraction wave separation, diffraction wave imaging 1. The tests with the Sigsbee2A model and noisy seismic data have shown that our method can effectively improve the resolution of diffraction wave imaging and that the constraint of STSSA increases the robustness to noisy data. We use STSSA as a constraint for PLSRTM, which greatly improves the imaging quality for diffraction waves. As there is no clear boundary between reflected and diffracted waves, the energy loss during separation leads to a slow convergence rate of the diffraction wave imaging technique. By establishing the Hanning window and the energy compensation function, it also compensates for the shortcomings of SSA in local dip processing and convergence of linear signals. The proposed STSSA algorithm exploits the properties of singular spectral analysis (SSA) to separate linear signals. To realize the separation of diffraction and imaging, a least-squares reverse time migration method of plane waves (PLSRTM) optimized with short-time singular spectrum analysis (STSSA) was developed in this work. Therefore, the separation of diffracted and reflected waves is a crucial step in identifying these small-scale diffractors. These are often superimposed by strong reflections so that they are not visible on the image, leading to misinterpretation and incorrect localization of the scatterers. Diffractions are seismic waves generated by small-scale heterogeneities in the subsurface. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |