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New Insights into the "Diagenesis and Paragenesis of the Upper Cretaceous Eagle Ford Group" I am excited to announce the publication of two recently published papers in Marine and Petroleum Geology that delve into the complex diagenetic and paragenetic history of the Upper Cretaceous Eagle Ford Group! These studies offer fresh perspectives on one of the most prolific unconventional reservoirs, unraveling the intricate geological processes that have shaped its unique properties. Depositional environment and burial/thermal history are master diagenesis controls because they impact original grain assemblages, redox state, temperature, types, and content of organic matter. Paper 1: "Early mudstone diagenesis of the EFG in the San Marcos Arch area" Explore the detailed kerogen type variation and diagenetic alterations that have influenced the reservoir characteristics of the shallow-buried EFG. Paper 2: "Diagenetic processes and paragenetic sequence of the EFG" This study provides a thorough examination of the paragenetic sequence, highlighting the timing and conditions of mineral formation. Key findings include: • Insights into the thermal history and fluid evolution of the EFG. From San Marcos Arch toward the Maverick Basin, the amount of uplift and erosion increases and impacts the burial and thermal history of the EFG. Although the present-day burial depth is shallower in the La Salle County when compared to the EFG in the Karnes County, the thermal maturity of the EFG is higher and the EFG was buried deeper in the La Salle County area than that in the Karnes trough. Clay mineral diagenesis becomes significant in the La Salle County with increasing temperature due to burial depth. The precipitation of illite, I/S, interlayered kaolinite-Mg chlorite, and Mg- and Fe-chlorite fills the original pore spaces in the La Salle wells, increasing capillary pressure and tortuosity, and decrease permeability. • Illitization trends were not observed in depth. This is because most smectite forms from alteration of volcanic ashes and the volcanic origin of the disorientated smectite did not follow regular illitization kinetics. • The ratio of marcasite to pyrite is higher in the UEF (average = 0.35) than that in the LEF (average = 0.1) because sediments in the UEF were deposited under more oxidizing than the LEF. These papers are essential reading for geologists, petrophysicists, and energy industry professionals who are keen to deepen their understanding of the EFG's geological complexity and diageneis in unconventional reservoirs. co-authors: Bob Loucks, Harry Rowe, Rob Reed, Evan Sivil, Rieko Adriaens, Gilles Mertens Mudrock Systems Research Laboratory (MSRL) Bureau of Economic Geology in collaboration with Qmineral Analysis & Consulting special thanks to Kitty Milliken who has shared her extensive experiences and knowledge on diagenesis and sedimentary rock petrography https://lnkd.in/guxCRzYe