Determination of seismic resolution: Some practical aspects from land seismic data

Reflection seismics is the most common geophysical method for obtaining structural images of the subsurface. It can image subsurface structures over large areas and depth ranges at high resolution. In order to make a reliable assessment of seismic imaging results, e.g. to quantify uncertainties, it is important to understand the concepts of seismic resolution. At brief, seismic resolution is the ability to distinguish between two seismic features from one another and resolve them separately.

Theoretical considerations to seismic resolution criteria and their implications for seismic imaging are discussed in many textbooks, but the practical use in interpretation is often difficult to achieve. This is, because the underlying parameters, e.g. the bandwidth and the velocity of the seismic signal, are not explicitly visible on the final stacked image, especially if the sections are depth converted.

However, the measure for vertical resolution is the dominant wavelength and the resolution criteria is expressed as a fraction of it, e.g. λ/4 criterion, whereas a measure of the lateral resolution is the Fresnel zone. Both of which can be computed by common functions that are available in most interpretation systems. As a result, seismic sections showing the spatial variability of both vertical and horizontal resolution are obtained that can be blended into the stacked seismic section. This gives a tool at hand – just like a seismic attribute – to estimate the limits of seismic resolution and access uncertainties in the final seismic image.