Clumped isotope record of individual limestone fabrics: A potential method to constrain the timing of oil migration

This study applied clumped isotope analyses to investigate how different limestone components (larger skeletal grains and enclosing matrix) cements may have varying degrees of susceptibility recrystallization during progressive burial. The results also provide new constraints on the temperatures cementation, nature waters involved, timing diagenetic events, effect oil emplacement inhibiting processes. We used measurements from core samples in two giant oilfields, together with petrography well-constrained thermal histories, reactivity fabrics whether displacement pore water by affected recognize seafloor micritization, as distinct indicate that record burial 60 °C to72°C coarse-blocky calcite 85 86 °C. Oxygen isotopes suggest both processes involve high water/rock ratios. Burial histories carbonate Δ47 values are estimate recrystallized 99 70 Ma formed at around 54 Ma. By contrast, matrix shows 68 90 °C, consistent continuous low ratios 50 large thus tend recrystallize early, but less reactive subsequent because larger crystal size, whereas more finely crystalline faithfully records maximum conditions. lower temperature recorded relative present reservoir is interpreted reflecting stoppage or inhibition emplacement.