Hydraulic Fracture Stimulation in a Fluid-filled Borehole via a TBEM Approach

In this paper, the Traction Boundary Element Method (TBEM) and the Boundary Element Method (BEM) are combined so as to evaluate the 3D wave field generated by 2D fluid-filled boreholes with a connecting hydraulic fracture. The problem is formulated in the frequency domain. The hydraulic fracture may exhibit arbitrary orientation and may present a very small thickness. The proposed formulation avoids the thin-body difficulty posed by the classical BEM formulation. All singular and hypersingular integrals are evaluated analytically, which overcomes one of the drawbacks of this formulation. Different source types such as 3D monopoles and dipoles loads may excite the borehole. The proposed model is first verified using a cylindrical circular fluid-filled borehole, for which analytical responses are known. Complex frequencies are used to avoid the aliasing phenomena in the time domain. The numerical results are analysed and a selection of spectra and animation plots from different hydraulic fracture configurations are presented. This allows the illustration of the significant scattered wave field modifications generated by a hydraulic fracture connected to the borehole.