Enhancing Geophysical Signals Through the Use of Savitzky-Golay filtering method

ResumenEn la cuenca de Sidi Chennane en Marruecos, existen inclusiones estériles de caliche que dificultan la extracción de las rocas fosfatadas y que son difíciles de detectar. La resistividad de los caliches excede un valor de 200 Ω-m contra 150 Ω-m para la roca fosfatada. Se realizó un trabajo de prospección eléctrica de tipo Schlumberger en una zona de 50 ha en la cuenca de fosfatos de Oulad Abdoun. Se obtuvieron modelos del perfil geológico mediante el filtro de Savitzky-Golay, y se logró localizar las inclusiones de caliche y las estimaciones de cálculo de las reservas de los fosfatos se encuentran muy circunscritas.

In the Sidi Chennane basin exploitation inclusions of sterile hardpan—so-called “derangements” — are hard to detect and interfere with phosphate extraction. A Schlumberger resistivity survey over an area of 50 hectares was carried out. The Savitzky-Golay filtering method was used as a tool for denoising the data.Savitzky-Golay (S-G) filters are one of the filters which can smoothen out the signal without much destroying its original properties. Despite their exceptional features, they were rarely used so far in the geophysical signal processing. The aim of this paper is the investigation of their properties in detail from the geoelectrical signal processing aspect. The experimental results indicate that S-G filter is better for denoising geoelectrical signal. Models of the geology were successfully obtained from Savitzky-Golay filtering method, which help mapping the phosphate deposit inclusions and the estimations of phosphate reserves were improved and better constrained.