Simulation study on equilibrium sand partitioning of horizontal multi-cluster fracturing well based on CFD

ABSTRACT: Multi-cluster fracturing technology of horizontal wells is the main technical method for effective and economic development in shale reservoirs. In order to obtain effective propped clusters and improve the non-equilibrium sand partitioning between clusters, the Eulerian-Eulerian model was applied to stimulate the proppant transportation and settlement in the wellbore-cluster model. Before applying the numerical model to the wellbore-cluster system, we conducted indoor experimental results to validate the model. After the validation, the base case was carried out to analyze the proppant distribution law in the wellbore/cluster system. Then, sensitivity analysis of different pumping rates, fluid viscosities, proppant sizes, and proppant densities was performed to find out the proppant placement. It is found that all cases have a heel bias, and flow rates reduction and uneven distribution of proppant concentrations in the wellbore is the main reason for the un-equilibrium partitioning of the proppants among the clusters. The sensitivity analysis shows that the un-equilibrium partitioning of the proppants by optimizing the pumping rate, proppant sizes and densities. Our study results can provide us more insights into the optimization of the multi-cluster fracture technology.