Experimental Design in reservoir simulation: an integrated solution for uncertainty analysis, a case study

Quantification of uncertain parameters in oil reservoirs is one of the major issues of concern. In underdeveloped reservoirs, there are many uncertain parameters affecting production forecast which plays a main role in reservoir management and decision making in development plan. To study the effect of uncertain parameters on the behavior of a reservoir and to forecast the probabilistic production of the reservoir, the simulator has to be run too many times with different entries for uncertain parameters. To avoid this heavy and time-consuming process, Experimental Design methodology is used which chooses the values of uncertain parameters from their ranges in a way that the total uncertainty in the system is captured with the least number of simulator runs. In this study, Experimental Design methodology is used to observe the effect of uncertain parameters on the production of an underdeveloped oil reservoir, which is subjected to immiscible gas injection method, and to estimate the probabilistic production of the reservoir; therefore, the proper and unbiased decisions for oil reservoir development can be made. Experimental Design methodology, as a powerful and trusted method, makes it possible to choose simulator runs so as to obtain accurate probabilistic production diagrams using the least number of runs as well as to study the impact of uncertain parameters on the oil reservoir production profile, quickly.