Fracture Diagnostics Research at the GRI/DOE Multi-Site Project: Overview of the Concept and Results

The Multi-Site Hydraulic Fracture Diagnostic Project was initiated to develop independent diagnostic technologies and methodologies that will result in increased accuracy in measuring hydraulic fracture dimensions. Through a series of field experiments, the project has provided key insights into the time-dependent growth and total dimensions of hydraulic fractures. Wireline-retrievable and cemented-in triaxial accelerometer arrays provide the basis for plan and profile maps of microseismic events associated with the hydraulic fracture. A vertical inclinometer array provides data on the earth's mechanical response to fracture opening and closure. A directionally drilled wellbore remotely intersected the hydraulic fracture interval, verified the accuracy of microseismically imaged hydraulic fracture azimuth, and provided ground-truth observations on the far-field character of hydraulic fractures. Although eleven far-field hydraulic fractures were observed, it cannot be definitively determined if they are the result of multiple injections. Collectively, data resulting from M-Site research indicate that hydraulic fracture wings are not always symmetrical, rapidly attain their full length extent with only limited fracture height growth, and that hydraulic fractures propagated only with fluid retain their width for a long time period. Although these results apply to the zones being tested at the M-Site, they should also transfer to other zones with comparable thickness and stress contrast.