Flat spot events are observed in post stack seismic data across a newly mapped structure at the Cretaceous Zubair Formation Top in Bihayth-Umm Neqa area, North Kuwait. Since Zubair sands are oil producers in the nearby Raudhatain field the flat events in the study area are interpreted to be DHI associated with oil-water contact (OWC). In order to validate the same prior to exploratory drilling, rock physics based AVA modeling is carried out. The challenges are non-availability of the required logs in the wells drilled in the study area. Therefore, we used well data of Raudhatain field to establish empirical relationship between elastic and petrophysical properties of Zubair sand and synthesized Vs and density logs in the flat spot location in the study area. Next, we applied the Biot-Gassmann fluid substitution technique to understand the fluid sensitivity of the Zubair sandstone. This model is also used for generating the synthetic AVA gather that is corroborating with the seismic angle gather. The AVA gather shows increasing amplitude with angle at the top of reservoir, probably indicating presence hydrocarbons. Therefore, flat spots in the post-stack data are indicating OWC in the reservoirs and the structure is a good candidate for Zubair exploration.


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