Depth prediction by using various velocity models of Khasib Reservoir in East Baghdad field, Iraq

In this study, the variance seismic attribute was used to track fault geomorphology, which interpreted in time. To convert these fault surfaces and isochron maps to depth, the velocity model was prepared. Therefore, 14 velocity models for depth conversion were built by using different equations in East Baghdad Field, central Iraq to depth conversion assessment and select a precise model from many candidates of velocity models to generate an accurate depth map. All the velocity models are divided into two main velocity layers. The upper-velocity layer represents the tertiary sequences, while the lower-velocity layer represents the Upper Cretaceous sequences. Three criteria are made in this study (mis-tie value, standard deviation analysis, and blind well test) to select the best depth map. The results reveal the velocity model-7 is better to use because the depth map of the Khasib Reservoir, which produced from model-7 shows less mis-tie between estimated and real depth, less standard deviation values, and lower errors at EB 24 and 26 well locations. The corrected depth map of Khasib Reservoir shows three structure noses. Two of them opened toward the NW direction, while the southern structural nose opened toward the SW direction with a minor enclosure.