Tuesday  |  Phipps  |  02:20 PM–02:40 PM

#13741, Use of Full-field Strain Measurements to Determine Mechanical Properties of Shale Under Repeated Cyclic Loading

Stimulation of unconventional hydrocarbon reservoirs in the form of shale deposits through hydraulic fracturing is a considerable resource to produce oil and gas. Consequently, it is important to understand the properties of shale, especially when subjected to repeated cyclic loading. This is because during drilling and hydraulic fracturing construction, surrounding rock are exposed to cyclic stresses which encompass micro-cracks, and their behavior affects mechanical response and failure, which in turn influence the hydraulic fracture process. In this study, Woodford shale materials obtained from Anadarko basin in Oklahoma are tested to determine the mechanical properties, post failure behavior, and the failure strength of shale. These properties are quantified under cyclic loading conditions using full-field strain measurements from digital image correlation (DIC) in conjunction with analytical expressions of the stress fields. Tests are carried out by loading perpendicular to the bedding planes. It is found that shale materials display significant anisotropy in material response and are also influenced by tensile or compressive loading conditions. This has important implication on the use of shale properties to predict hydraulic fracturing parameters that will lead to optimum yield.

Achyuth Thumbalam Guthai   Oklahoma State University
Ali Fahem   Oklahoma State University
Raman Singh   Oklahoma State University