Investigation of geochemical anomalies associated with oilfields using matching magnetometric data and satellite images, case study: Moghan plain

In recent years, exploration methods based on studies of alterations due to hydrocarbon leakags from reservoir to the surface have been considered. Since these leaks occur as vertical chemnies upon the oil traps, these seeps have a relative adaptation to the position of hydrocarbon reservoirs. The purpose of this study was to process and interpret the geological, remote sensing, surface geochemical exploration data of Moghan sedimentary basin and then match the results of these data with possible hydrocarbon rich areas. In remote sensing studies, band ratio methods, RGB color composition and principal component analysis were used to identify ferrous iron, carbonate replacement by gypsum and clay minerals alterations. Also, surface magnetic anomalies were identified by applying analytical signal analysis, first derivative and continues highpass filter on ground magnetic data. Adaptation of concentration of positive geochemical anomalies first to the anticline layer and then to the combined faults and anticline layer showed that alteration of carbonate minerals and illite were the most significant altered zone observed upon the anticlines, and Ferrous iron and the surface magnetic anomalies are the least of them. Also, the concentration of positive geochemical anomalies on the anticline is higher than the area without anticline and if the faults are used, this concentration will almost double. It proves the possible leakage of hydrocarbons from the reservoirs to the surface and the creation of geochemical anomalies above them. This finding can help to locate the approximate location of underground reservoirs and significantly reduce the cost of drilling operations.