“…Experiments with heated shale indicate that fracture initiation on the microscale starts from small preexisting flaws that promote stress concentration, such as elliptic pores or kerogen patches in shale (e.g., Figueroa Pilz et al, 2017;Kobchenko et al, 2011;Panahi et al, 2019). Similar fracture initiation mechanisms were observed in analogue experiments using brittle, elastic gelatin-yeast mixtures, where a drainage fracture network developed from elliptic gas bubbles (Kobchenko et al, 2014;Vega et al, 2018). Fracture propagation is thought to be driven by continuous liquid and gas production, and several factors may influence the propagation direction: (1) initial orientation of kerogen flakes or thin pores, for example, due to sedimentary lamination, (2) external stress field configuration, and (3) internal stress interactions (Kobchenko et al, 2011;Panahi et al, 2018;Vega & Kovscek, 2019;Vernik, 1994).…”