Comparison Of Methodologies To Evaluate The Risk Of Petroleum Fields

A risk analysis process can be applied to several phases of a petroleum field. The methodologies required in the decision-making process depend on the level of uncertainties, which vary according to the field phase. This work is focused on the development phase and the decision process is based on probabilistic procedure to represent all possible scenarios of the reservoir. The uncertain attributes can be combined through derivative tree or Monte Carlo technique. The risk can be evaluated by the Net Present Value, which depends on the reservoir performance. The reservoir production prediction can be obtained through numerical simulation or response surface. Most of works consider only the application of these procedures and comparisons of these techniques are not well evaluated. The goal of this work is to apply the alternative combinations of these techniques to petroleum fields and compare them to determine the result reliabilities. The combination of Monte Carlo and numerical simulation is not viable, in some cases, due to the great number of simulations. The attribute combination by derivative tree can be an alternative, but can also yield a high number of simulation runs. Alternatives to speedup the process are to reduce the number of attributes and their discretization levels or substitute the conventional reservoir modeling by faster ones, such as the response surface, which is suited to evaluate the impact of uncertainty on production forecasts. The contributions of this work are to: (1) to determine if the response surface can substitute the reservoir simulator, (2) to evaluate the capability of the response surface to substitute the reservoir simulator in order to obtain the risk curves, (3) to provide a guide to select an adequate combination of techniques according to the desired precision and (4) to determine if it is possible to reduce the number of simulation runs, maintaining the precision. Copyright 2007, Society of Petroleum Engineers.210161023Box, G.E.P., Behnken, D.W., Some New Three Level Designs for the Study of Quantitative Variables (1960) Technometrics, 2, pp. 455-475Costa, A.P.A., Schiozer, D. J.: Aceleração do Processo de Análise de Risco Aplicada no Desenvolvimento de Campos de Petróleo, XXV CILAMCE, Recife, Brazil, 2004Damsleth, E., Hage, A., Hydro, N., Volden, R., Maximum Information at Minimum Cost - A North Sea Field Development Study using Experimental Design (1991) Offshore Europe Conference, , SPE 23139, ScotlandDemirmen, F., Subsurface Appraisal: The Road from Reservoir Uncertainty to Better Economics (2001) SPE Hydrocarbon Economics and Evaluation Symposium, , SPE 68603, Dallas, USALigero, E.L., Madeira, M.G., Schiozer, D.J., Comparison of Techniques for Risk Analysis Applied to Petroleum Field Development (2005) SPE Latin American and Caribbean Petroleum Engineering Conference, , SPE 94806, Rio de Janeiro, BrazilLigero, E.L., Schiozer, D.J., Risk Analysis Applied to Petroleum Field Development: Automated Methodology and Parallel Computing to Speedup the Process (2002) Second Meeting on Reservoir Simulation, , Buenos Aires, ArgentinaLigero, E.L., Maschio, C., Schiozer, D.J., Quantifying the Impact of Grid Size, Up scaling and Streamline in the Risk Analysis Applied to Petroleum Field (2003) SPE Reservoir Simulation Symposium, , SPE 79677, Houston, USA, FebruaryNewendorp, P., Schuyler, J., (2000) Decision Analysis for Petroleum Exploration, , Planning Press, 606pp. Colorado, USAMadeira, M.G., Comparação de Técnicas de Análise de Risco Aplicadas ao Desenvolvimento de Campos de Petróleo (2005), Msc Thesis, 133pp, UNICAMP, Campinas, BrazilMontgomery, D.C., (1997) Design and Analysis of Experiments, , John Wiley & Sons, Fourth Edition, EUARisso, F.V.A., Risso, V.F., Schiozer, D.J., Aplicação de Planejamento Estatístico e Meta-Modelos na Análise de Risco de Campos de Petróleo (2006) Rio Oil & Gas Expo and Conference, , Rio de Janeiro, BrazilRose, P., Risk Analysis and Management of Petroleum Exploration Ventures (2001) AAPG Methods in Exploration Series, 12. , No, Tulsa, Oklahoma, USASchiozer, D.J., Ligero, E.L., Suslick, S.B., Costa, A.P.A., Santos, J.A.M., Use of Representative Models in the Integration of Risk Analysis and Production Strategy Definition (2004), 44, pp. n1-n2. , JPSE, ppl31-141Schuyler, J., (2001) Risk and Decision Analysis in Projects, , Project Management Institute Inc, Second Edition, USASteagall, D.E., Schiozer, D.J., Uncertainty Analysis in Reservoir Production Forecast during the Appraisal and Pilot Production Phases (2001) SPE Reservoir Simulation Symposium, , SPE 66399, February, Dallas, US