Estimating permeability from hydraulic fracturing induced microseismicity

Hydraulic fracturing is often performed to enhance the permeability of hydrocarbon bearing shales and tight sands. The microseismic event clouds accompanying the fracturing operations have been used for permeability estimation by attributing the triggering front observed in the distance versus time plots to pore pressure diffusion. We show that in low-permeability hydrocarbon reservoirs like shales and tight sands, the growth rate of hydraulic fracture can be much faster than that of the pore pressure diffusion front. Therefore, the observed triggering front in such cases may be attributed to crack tip propagation. Moreover, equating the triggering front to the diffusion front yields highly overestimated diffusivity values. We propose to use the width, instead of the length, of the microseismic cloud to get a better diffusivity estimate. Presentation Date: Tuesday, September 17, 2019 Session Start Time: 8:30 AM Presentation Start Time: 11:25 AM Location: 303B Presentation Type: Oral