Discrete element-based multi-cluster hydraulic fracture extension study with temporary plugging and fracturing in horizontal wells

Abstract

In this paper, a two dimensional-discrete element method complex fracture extension model was developed to simulate the fracture extension behavior in reservoirs during multi-cluster perforation fracturing of horizontal wells by particulate flow and considering temporary plugging conditions. The effect of particle inhomogeneity on the extension of multi-cluster fractures, the change of fracture extending characteristics before and after temporary plugging, and the effect of geological and construction parameters on the extension of multi-cluster fractures under the consideration of temporary plugging conditions are investigated in this model. The results show that: (1) the middle cluster is more difficult to extend than the outermost cluster due to interstitial stress interference; the increased nonuniformity of particles aggravates interstitial stress interference and favors shear fracture extension. (2) Fractures expand substantially when the fracturing fluid reaches 3/4 of the total fluid volume; after temporary plugging, it can promote the uniform extension of fractures and increase the total length of fractures, but the fractures formed in the middle are easy to be captured by the fractures at the two ends and expand along it, and it is not easy to form complex fractures; the timing of plugging is based on the percentage of perforation clusters with fractures already formed, with fracture extension being preferred. (3) The horizontal principal stress difference mainly affects the direction of fracture extension; the number of clusters mainly affects the uniformity of fracture extension; and the fluid flow mainly affects the length of fracture extension.