Quantifying the differences of estimated parameters from 3d fracture network upscaling methods

The fractures in rock matrix are the fundamental units for calculations of flow and contaminant transport in fractured formations. Due to the complex networks and relative small volumes, it is difficult to account suitable simulation domain for such small units for simulations of flow and transport in large-scale problems, how to upscale modeling becomes one of a serious problem. There are two methods to decide a suitable simulation domain, one is employee Monte Carlo simulation to determine a hydraulic connected model and second method is generate an ECPM with discrete fracture method. Both of two methods cost many computational resources until recently, how to compute effectively becomes one of important issues in upscaling problems. To solve this problem, we use field data to evaluate the probability of hydraulic connectivity as the basis of representative simulation domain and analyze the sensitive of hydraulic connectivity with synthetic fractures networks. In addition, we also constructed a numerical model with previous observed data to estimate influences of each upscaling parameters. The results of this study show that varied fracture statistical parameters can quantify the probability of hydraulic connectivity and also proposes fracture intensity to be the base size of modeling domain. Moreover, our results also show that we can distinguish two different upscaling method between different sizes of grid from using field data: Oda method is availed when the block grid is smaller than the fracture mesh and Block method is suitable when the block grid is bigger than fracture mesh. Base on the research results in this study, an opportune grid size can be determined in the future upscaling researches.