Offset-continuation trajectory stack

Abstract

We introduce a data-driven stacking technique that transforms 2D/2.5D prestack multicoverage data into a commonoffset (CO) section. We refer to this new process, which is based on the offset-continuation operation (OCO), as offsetcontinuation trajectory stacking or briefly OCT stack. Similarly to the CMP and CRS stacks, this new method does not rely on an a-priori velocity model but provides velocity information itself. The original offset-continuation-operation (OCO) method is a seismic configuration transform designed to simulate a seismic section as if obtained with a certain source-receiver offset using the data measured with another offset. Since an OCO depends on the velocity model used in the process, it can be combined with stacking techniques for a set of models, thus allowing for the extraction of velocity information. The algorithm is based on so-called OCO trajectories, which are related to the concepts of image waves and velocity rays. We theoretically derive the OCO trajectories from the kinematic properties of OCO image waves that describe the continuous transformation of the common-offset reflection event from one offset to another. Based on OCO trajectories, we then formulate a horizon-based velocity-analysis method, where root mean square (RMS) velocities and local event slopes are determined by stacking along event horizons. A numerical example demonstrates the feasibility of the method.