Quality Assurance of Spatial Sampling for DMO

One of the goals in planning and designing seismic surveys is to provide adequate spatial sampling. Spatial sampling has an Influence on many aspects of data processing and Interpretation. Since DMO and wave processes like DMO have become almost universal data processing procedures, the Interplay of spatial sampling and these wave-equation processes Is Important! Poor spatial sampling is often observed to affect waveequation processes such as DMO and migration. Inadequate spatial sampling can result for a variety of reasons. Offshore, irregularities are caused by obstructions, cable feathering, and the acquisition environment; on shore, obstructions and the inability to occupy desired stations are problems. However, a more fundamental problem occurs when the acquisition design itself is deficient. Conventional survey-design specifications such as CMP fold and offset distribution are aimed at achieving a uniform stack of the data. Here I develop similar attributes for evaluation of survey geometries that are based on the application of DMO and stack to the data. These new attributes can be anatyzed-as offset, fold, and azimuth now are in current practice. Both the survey design and acquisition quality control phases of seismic surveys can use these attributes to optimize the resulting DMO; stack, and migration. My method is based on previous work on DMO equalization (Beasley and Klotz, 1992). Uke conventional methods, the analysts requires only the survey geometry. It provides an accurate and practical means of assessing the suitability of the spatial sampling of a seismic survey for wave-equation processing.