Estimating the distance from the hydraulic fracture tip to the monitor well can be useful for characterizing fractures, optimizing well spacing, and preventing parent/child well interference. A heart-shaped signal is referred to as the extensional precursor of a fracture hit recorded by cross-well strain measurements and can serve as a vital tool for such estimation.
This study incorporates the 3D displacement discontinuity method to understand the effect of fracture geometry and monitor-well offset on the heart-shaped signal’s characteristics. Results from numerical simulation and analytical solutions reveal a strong linear correlation between the spatial extent of the heart-shaped signal and the fracture tip distance.
This relationship was further developed to predict tip distance using field data from the Hydraulic Fracture Test Site 2. A reasonable approximation result from field data further validates the methodology. In addition, it is worth noting that the estimation accuracy depends on the ratio between fracture dimension and tip distance.
The findings of this study offer a novel approach for real-time monitoring and characterizing of hydraulic fracture propagation, which can be further used for well spacing optimization in unconventional and enhanced geothermal system reservoir development, as well as caprock integrity monitoring for carbon sequestration projects.
This abstract is taken from paper SPE 223631 by P. Li and G. Jin, Colorado School of Mines and National Energy Technology Laboratory; R. Hammack and C. Kohnke, National Energy Technology Laboratory; and K. Wu, Texas A&M University. The paper has been peer reviewed and is available as Open Access in SPE Journal on OnePetro.