CHEMOSTRATIGRAPHIC PROFILE OF A RESERVOIR IN WELL “X” OF FIELD “Y” OFFSHORE SOUTHERN GABON

Abstract

Chemostratigraphy is a useful way to link sedimentary layers based on how the amounts of major, minor, and trace elements change over time. The chemical analysis of a cross-section of a reservoir from the offshore Gabon well "X." From ditch cuttings at depths between 2720m and 2947m, 14 samples of sandstones, siltstones, conglomerate, silty shale, and shales were taken. Eleven (11) of these samples were chosen for X-ray diffraction (XRD) and Xray fluorescence (XRF) testing (XRF). The deeper series, which was made up of older deposits, was mostly made up of shale. The shallower part was made of sandstone, and volcanic poufs could be seen when they were looked at under a microscope. The analytical results showed the presence of minerals, which can be seen in the XRD profiles of the minerals and elements, which show how they change along the cross section of the reservoir. Elements like K, written as K2O, and Mg were not found in samples taken from a shallower depth range of 2720m to 2850m. But the amount of all other elements in samples taken between 2,850 and 2,947 meters deep went up with depth. The fact that volcanic turfs were found at an altitude of 2910 meters showed that volcanic materials were released because of a tectonic event. Between 2720 and 2880 meters deep, where the volcanic event happened, the sandstone may have been heavier because of the gases that came out of it. The K2O and Mg content of the cross-variable section of the reservoir is used to tell the difference between the paleoclimate and weathering. The section between 2720m and 2850m deep doesn't have any Mg and K2O, but the samples from deeper down do. Compare this to things like aluminum and other elements that are heavier. K2O and Mg are very mobile elements that could have been eroded away much earlier, leaving only Al and heavier elements behind. It is possible that these sandstones were exposed to chemical weathering in a warm and humid environment, which is ideal for chemical weathering.