Qiangqiang Kang ¹ Jiagen Hou ^1* Xun Hu ^1* Yuming Liu ¹ Quan Ren ² Mingqiu Hou ³ Yanshu Yin ⁴

• ¹ College of Geosciences, China University of Petroleum, Beijing, China
• ² SINOPEC Geophysical Research Institute Co., Ltd, Nanjing, Nanjing, China
• ³ Research Institute of Petroleum Exploration and Development (PetroChina), Beijing,, Beijing, China
• ⁴ Yangtze University, Hubei, Wuhan, Wuhan, China

Iterative geostatistical seismic inversion is a vital technique for estimating subsurface properties.However, a conventional single-scale strategy faces challenges in preserving large-scale geological features due to the limited restoration of the type of data template, and conventional multiscale strategies face the challenge in that it is easy to lose the large-scale structure that was previously preserved. This paper introduces a novel smoothed multiscale strategy aimed at overcoming these limitations, which comprises two components: Simulated annealing at the coarsest scale and smooth conversation between two scale grids. This approach offers a smoother way to simultaneously retain large-scale and small-scale structures, improving the overall accuracy of the subsurface property estimations. To validate the effectiveness of our approach, we apply it to both synthetic and real examples. The results show that the simulated annealing strategy at the coarsest scale grid explores the prior space and finds the best large structures to avoid the generated models trapping in the local minimal. Meanwhile, and the smooth conversation strategy between two scale grids helps us avoid the damage of the coarser structure.It can be explained that a large weight is assigned to the coarse structure at the beginning of the conversation of two grid scale, reducing the likelihood of the replacing proposed local small-scale geological patterns, which prone to be accepted in the conventional multiscale strategies. The combination of the two strategies used in the proposed smoothed multiscale strategy displays a significant improvement in subsurface property estimation accuracy compared to traditional multiscale strategies. This innovation can have far-reaching implications, benefiting a wide range of geophysical applications and contributing to more accurate and informed decisionmaking in geological and hydrogeological assessments.