Reflecting on Seismic Inversion: An integrated case study of using inversion products for reservoir description

Summary This paper discusses an Egypt offshore development comprising 5 gas & condensate reservoirs, one of which includes a Miocene-age turbidite gas field. Seismic inversion products were used to estimate the reservoir section net-to-gross (NtG) and net sand thickness. Due to the limited number of well penetrations and associated dynamic data, seismic is the main tool in accounting for well bias in the prediction of NtG at fieldwide scale for GIIP estimation and at local scale for development well target selection. Qualitative, and quantitative assessment of the seismic products hold great value for the reservoir description. The ‘One Dimensional Stochastic Inversion’ (ODiSI) workflow was used to estimate a series of reservoir properties along with their uncertainty products, using the best lithology projection. A series of geological and seismic scenarios were tested to capture potential subsurface cases using the uncertainty products. The primary objective was to understand the NtG and net sand thickness distribution away from the well control points. A secondary objective was to use the ODiSI output products as an input to build multiple models and test the impact of seismic data on the simulation model prediction.