Paper Summary
The Lower Zubair sand reservoirs have produced or shown oil in several but not all of the wells drilled in western and southeastern Kuwait. Evidence from the available core and log data analysis suggests that the Lower Zubair sand distribution consists of NESW trending estuarine channel fill. Thin due to their stratistructural nature, these Zubair sands are present at some places and absent at others. The tectonic activity in the area has resulted in faults and fractures in the interval comprising not only the Lower Zubair sands but the Middle and Upper Zubair sands as well. In general, the impedance contrast between these thin Zubair sands and the underlying Ratawi shale is poor. Therefore, the challenge is to identify not only the spatial variability of these Lower Zubair sands but also crosscutting faults and fractures. We address these challenges by first enhancing the bandwidth of the available seismic data using spectral inversion to estimate thin bed reflectivity, followed by relative acoustic impedance to map the reservoir heterogeneity, and that in turn followed by coherence and curvature attributes to detect minor faults and fractures.
