The Influence of Data Processing Parameters on Seismic Quality Attributes: A Synthetic Data Study
Authors: Brice Tim , Armstrong Phil 
Published: October 2008

This paper investigates the effect of processing parameters on the behavior of certain seismic data quality attributes such as borehole match power, resolution factor and bandwidth. A number of ID and 2D models were constructed and diagnostic plots using different processing parameters and quality attributes were used to evaluate and compare the attributes. The 2D models were used to investigate how lateral structural variations affect borehole match power and how correction for dip might be made in the vicinity of the borehole.

It is suggested that quality attributes might be used to:Control the quality of data during acquisition;Guide the processor towards an optimum processing flow by maximising some or all of the attributes, andQuantify the quality of the final processed data.

This could reduce the cost and turnaround time of seismic data whilst improving their quality.

Borehole match power ratio is a measure of the degree of similarity between two traces, in this case a modelled zero offset VSP reference trace and a modelled surface seismic trace. Other attributes describe the statistically generated wavelet from a single surface seismic trace. Borehole match power was found to be an excellent tool for gauging the qualityof the seismic trace as it was very sensitive to variations in model structure and to the presence or absence of multiples. It can be used to pick the optimum processing parameters for multiple suppression and for the best quality stacked trace. In the 2D models constructed it was possible to apply a dip correction to the VSP data. It is therefore possible to use the method in areas of some structural complexity with unmigrated data.

The statistically derived quality attributes mirror borehole match power to differing degrees, resolution factor being the most effective, and might be used in the absence of borehole data. Therefore selection of processing parameters mightultimately be guided by a combination of quality attributes with or without borehole data.

Introduction

The use of seismic quality attributes or "quality indicators" allows the quantification of the quality of seismic data. In the past the quality of both unprocessed field data and processed seismic data has been subjectively assessed by visualinspection. The calculation and plotting of quality attributes allows objective assessment of data and may be used to improve its quality by optimizing acquisition and processing parameters. Quality attributes may also be used to prove that the survey has met its predefined objectives.

Both statistical and deterministic methods are used:Statistical attributes are generated from surface seismic data both before and after processing, and;Deterministic attributes are generated through the matching of borehole data with surface seismic data.

One of the main features we wish to quantify is the resolution of seismic data. The optimum wavelet shape for resolution may vary depending on our objectives and the designing of a single quantity for resolving power may be anover simplification (see Berkhout1).