Brazilian Pre-Salt Gross-Rock Volume Uncertainties: Integration Between Velocity Model and Seismic Resolution
M. Paes, C. Pereira, V. Pinto, A. Maul, M. Gonzalez, T. Meneguim, G. Gonzalez, R. Sundt Meyer and S. Lervik Furland
Event name: 81st EAGE Conference and Exhibition 2019
Session: Poster: Risk and Uncertainty
Publication date: 03 June 2019
Info: Extended abstract, PDF ( 884.35Kb )
Price: € 20
The reservoir characterisation and project development in Pre-Salt reservoirs in Santos Basin, Brazil, represent big challenges to the geoscientists. This is mainly due to the lack of well information, its quality and resolution support related to the seismic data, generating depth uncertainties regarding velocity modelling. Aiming to analyze and quantify the impact of parameter uncertainties in the structural model, two different approaches to build velocity models were applied. The first scenario utilizes a constant velocity value of 4,500 m/s in all salt section. The second scenario considers different velocities of the stratified salts to build the velocity model. For each scenario, a set of 300 realizations was created, to account for the uncertainties in the structural modelling and were analyzed based on their Gross Rock Volume (GRV). The differences between the pessimistic and optimistic realizations were close to 1.6% and 2%, for scenarios 1 and 2, respectively. These differences represent considerable GRV volumes variation of approximately 3.109 m3. Additional parameters such as Net-to-Gross (NTG), porosity and oil saturation, can also influence oil reserve calculations, and should be included in future uncertainty studies.