Volume 20, Issue 1 (March 1997)
Influence of Intersection Angle at Single-Well Flow Tests in Fracture-Wellbore Systems
The intersection angle between a hydraulically effective fracture and an active wellbore influences the response observed in single-well tests. An experimental study was launched to investigate the ability of a semi-analytical model proposed to account for this influence. The setup designed for this purpose includes three distinct fracture-wellbore system models with 90°, 20°, and 10° intersection angles, each assembled into a steel box frame to provide a constant fracture aperture during testing. The laboratory program involved testing each of these models for three different fracture apertures under steady, constant-flux, injection, and pumping conditions. The overall experimental setup successfully simulated the conceptual testing environment in which the mathematical model is expected to reproduce. Analysis of the test results confirmed the effectiveness of the conceptual model in refining the predictions of single-well tests. Important applications include the determination of anisotropic rock-mass permeability in a single, arbitrarily oriented wellbore by isolating fractures of different sets and of optimum wellbore orientation and spacing for maximum efficiency of producing wells.