Dynamics of cementation in response to oil charge: Evidence from a Cretaceous carbonate field, U.A.E.

Unlike the oil leg cements, the final zone in the water leg occludes nearly all remaining pore space. The δ18OVPDB of bulk micrite from the water leg shows an average of −7.4‰ (n = 9) compared to −6.2‰ (n = 10) from the oil leg, suggesting the precipitation of further micrite cement at greater burial depths. We infer that burial cementation slowed in the presence of oil due to a reduction of potential nucleation sites as well as porewater and solute movement within weakly oil-wet pores, whereas continued flow and solute movement through all pores including the micropores (< 10 μm diameter) enabled extensive cementation in the water leg.