Analysis of Factors Affecting Residual Moveout Picking and Solutions

Abstract

Reflection tomography on the base of common image gathers (CIGs) in offset domain or angle domain is the powerful and mostly used tool for velocity inversion. There are many factors that affect the accuracy and resolution of reflection tomography, in which RMO picking is a quite important one that can’t be ignored. Residual moveout Auto Picking on common image gathers is the most important step in tomography velocity inversion, the reliability of residual moveout picking decides the accuracy of tomography velocity inversion. Based on a case study of field data, the paper give a full discussions and experiences analysis of factors such as grid step, input data quality, geological structure, picking parameter, which affect residual moveout picking greatly. Furthermore, the paper also put forward corresponding suggestions and solutions to reduce or eliminate the impact of these factors on residual moveout picking. At last we implement a structure controlled residual moveout picking method with horizon constraint to a field data residual moveout picking. The proposed picking method refines the global picking though utilizing horizon constraint in vertical orientation and structure subdividing in lateral orientation. It effectively improves residual moveout quality and enhances inversion reliability, and also helps tomography inversion to update a velocity model with high resolution. The final prestack depth migration shows a good imaging of complex structures and faults, which demonstrates how important of the role that the fine residual moveout picking method plays in tomography inversion.