The Impact of Hydrothermal Fluids on Porosity Enhancement and Hydrocarbon Migration in Qamchuqa Formation, Lower Cretaceous, Kirkuk Oil Company

The Lower Cretaceous reservoir core samples from the upper part of Qamchuqa Formation, Baba Dome, Kirkuk Oil Company, show evidence for multistage episodes dolomitization and a complex diagenetic history. Optical microscope reveals muti-phase diagenesis: an early stage diagenesis its alteration, later, by evaporated seawater under near-surface setting conditions, followed different event dolomitization. stylolite microstructures postdate anhydrite matrix dolomite crystals (DI) predated coarse rhombohedral (DII) saddle (SD), which were formed deep burial realm. High-resolution data stable isotopes integrated with intensive optical observation, ImageJ software, litho-log are utilized to establish qualified methods mapping better image hydrothermal subsurface conditions. These revealed types dolomites, mostly focused on fractures void spaces, paragenetic sequence shows history carbonate rocks hosted in limestone Formation. is started older younger as follow: Micritization, mineral formation, dolomite, stylolization, crystals. phase usually corroded hydrocarbon phase, and, geometrically, overgrown dolomite. Therefore, dolomitizing fluids enhanced porosity system had positive impact movement. This formation associated first groups δ18OVPDB δ13CVPDB data, narrow range oxygen values, inverse Js Lohmann curve fits towards shallow settings. Detailed supportive oxygen-carbon confirm presence hot condition. latter supported light constant heavy δ13CVPDB, indicates fluid possibly circulated this channeled along fracture pore consistent migration. spaces influenced leaching migrations sitting However, remarkable pristine microfacies host was preserved. In summary, study will add new understanding insight into origin, genesis, timing these dolomites their direct connection exploration development most oil rocks, exposed fluids. Additionally, adds whereas previous reported work has rock.