Our Speakers:

Dr. Ge Jin
Associate Professor,
Colorado School of Mines

Abstract:

This presentation highlights new insights gained through Distributed Fiber Optic Sensing (DFOS). Acting as a “subsurface nervous system,” fiber-optic cables installed in offset monitoring wells simultaneously record high-frequency microseismic signals and high-resolution strain changes. These measurements enable imaging of pre-existing fractures and direct observation of their reactivation during hydraulic stimulation.

Using field examples from unconventional oil and gas reservoirs and Enhanced Geothermal Systems (EGS), we demonstrate how local geology can significantly influence fracture growth and behavior. Key observations include:

• Hydraulic fracture deflection by natural fracture networks
• Large-scale shear reactivation along clay-rich horizontal bedding planes
• Fracture redirection caused by pre-existing geological features

These high-resolution DFOS measurements provide unprecedented insight into the relationship between geology and fracture mechanics. The results offer valuable opportunities to:

• Optimize stimulation efficiency
• Improve fracture network characterization
• Reduce operational risk and enhance well integrity
• Better understand and manage induced seismicity

By revealing how hydraulic fractures interact with existing subsurface structures, DFOS is transforming our ability to characterize reservoirs and improve stimulation design.