The Simulation Study of Fracture Vertical Propagation in 3D Model

How to control fracture propagation in vertically is still hot topic but difficult issue in hydraulic fracturing. The technology of controlling fracture height should be optimized for adapting to the different geological conditions. Although a great amount of research have been conducted to study the mechanism of fracture propagation vertically, there are mainly qualitative or half quantitative analysis that can not guide treatment designing directly. This paper focused on establishing new simulation methods including large scale physical experiment and fully 3D numerical model that can simulate fracture propagation from lab scale to field scale. The multiple factor sensitivity analysis on fracture height will also be discussed. In this paper, a new poly-axial experimental technology for hydraulic fracturing is innovated to load three-layers horizontal stresses independently. With the theory of similarity, the experiments have been conducted to investigate the effect of layered stress differences on fracture height. Then a more advanced 3D numerical model based on Displacement Discontinuity Method (DDM) is optimized. The numerical simulation results are proved well by comparison with the experimental results. According to the simulation, the effect of the difference between layered horizontal stresses, the difference between layered Young Modulus and the pumping rate on fracture propagation vertically are investigated quantitatively.