Dominant wavelength: a tool for morphological simplification of stylolites

Abstract

Stylolites are intergranular dissolution structures commonly found in carbonate petroleum reservoirs and have a complex geometry characterized by multiple wavelengths. A classical and natural approach to simplifying the morphology of a stylolite is to focus on its dominant wavelength (DWL), but the advantages and disadvantages of this simplification are poorly understood. We propose a new analysis procedure for testing the dominant wavelengths as a tool for the morphological simplification of stylolites. Hundreds of stylolite samples from carbonate rocks of the Água Clara Formation at the Rio Bonito Quarry (RBQ), Brazil, had their dominant wavelengths extracted and selected through the Fast Fourier Transform and Bandpass Filters. Two types of DWL results were obtained: (i) numerical DWL, a quantitative result that shows a strong correlation with stylolite amplitude and length, with R values between 0.47 and 0.84; (ii) graphic DWL, a qualitative result showing the simplification of the main stylolites features, which is more easily applied to stylolites with wavy teeth. Based on the DWL results, it is possible to state that there is a directly proportional relationship between the scale of a stylolite and its dominant wavelength, corroborating the self-affine nature of the analyzed stylolites. In addition to standard geometric analysis, the DWL method emerges as a novel tool for characterizing and visualizing the undulatory components of stylolites, simplifying their morphology, and contributing to the modeling of oil and gas reservoirs.