Utilization of percolation approach to evaluate reservoir connectivity and effective permeability: A case study on North Pars gas field

Reservoir characterization, especially during early stages of reservoir life, is very uncertain, due to the scarcity of data. Reservoir connectivity and permeability evaluation is of great importance in reservoir characterization. The conventional approach to addressing this is computationally very expensive and time consuming. Therefore, there is a great incentive to produce much simpler alternative methods. In this paper, we use a statistical approach called the percolation theory, which considers a hypothesis wherein the reservoir can be split into either permeable (i.e. sand/fracture) or impermeable flow units (i.e. shale/matrix), and assumes that the connectivity of permeability contrasts controls the flow. We developed master curves for the reservoir connectivity and its associated uncertainty, as well as the effective permeability and its associate uncertainty curves. To validate the approach, we have used the data set of the North Pars gas field located at the North of the South Pars field in the Persian Gulf. We have shown that the percolation approach gives reliable predictions when compared with results from a conventional reservoir modeling approach. Moreover, the first approach, as obtained from algebraic manipulation, is very fast, whereas the latter is very costly and time consuming.