Abstract The timing of petroleum migration in samples of fractured Cretaceous reservoir limestones from Oman and the United Arab Emirates is determined from observations of hydrocarbon fluid inclusions in calcite cements. Petrography and geohistory analyses of four wells that were variably affected by formation of the Oman Foredeep reveal five stages of diagenesis, fracturing, and fluid migration. (1) Quiet shelf deposition: early cementation associated with regional unconformities: (2) pre-orogenic shelf emergence: fractures cutting Stage 1 cements are healed by very cloudy, cleaved, and twinned calcite containing microfractures with yellow-white Hourescent, hydrocarbon fluid inclusions; (3) initial foredeep downwarp: fractures cross cutting Stage 2 fractures are healed with cloudy, cleaved, and sometimes twinned calcite containing dull-blue fluorescent, hydrocarbon fluid inclusions; (4) rapid subsidence and filling of foredeep with sediments including flysch. exotic blocks, and thrust toes: burial and tectonic stylolites crosscut Stage 2 and 3 fractures; and (5) uplift of the Oman Mountains: fractures cross cutting all diagenetic features are filled with clear, untwinned and uncleaved calcite containing only non-fluorescent, aqueous fluid inclusions. By correlating stylolite formation with overburden of approximately 2500 ft. (750 m), the hydrocarbon inclusions in Stage 2 fractures must predate all of Stage 4 and most of Stage 3. In the deepest portions of the foredeep, close to the Oman Mountain front, this correlation limits the presence of oil in fracture porosity to late TUronian-early Campanian time. Farther to the west, in the shallower parts of the foredeep. the timing constraint relaxes, and oil migration occurred as late as early Tertiary.