Inferring hydraulic connectivity of induced fractures in the near-wellbore region using distributed acoustic sensing-recorded tube waves excited by perforation shots

Abstract

We have developed a novel use of tube waves excited by perforation (or “perf”) shots and recorded on distributed acoustic sensing (DAS) to infer and compare the hydraulic connectivity of induced fractures near the wellbore on a stage-by-stage basis. Evaluating the fracture connectivity near the wellbore is critical because it controls the flow of the hydrocarbons from the formation to the wellbore. Currently, there are no established methods used to assess this property. However, we discuss how tube-wave decay rates can be used to infer relative differences in fracture connectivity between stages and, through field observations on DAS, demonstrate the correlation between decay rates and frac effectiveness. In addition, we consider other potential uses of these data in unconventional wells such as assessing plug integrity and constraining fracture geometry with Krauklis waves. DAS data are commonly acquired during the perf shots but primarily for fiber depth calibration purposes and have not been well studied. Our work illustrates the untapped potential of these data and how it can be easily repurposed to bring new insights about fracture characteristics in the near-wellbore region.