REMINDER: October 13th, 2022 DGS Luncheon Presentation – Dr. Ge Jin

Complex Hydraulic Fracture Propagation Behavior Revealed by Cross-well Strain Measurement

Dr. Ge Jin, Colorado School of Mines

Abstract:

Understanding the propagation of hydraulic fractures is critical for low porosity, low permeability unconventional reservoir development. In this study, we use cross-well strain measurement based low-frequency distributed acoustic sensing (LF-DAS) to monitor the hydraulic fracturing operations in the Chalk Bluff field in the Denver-Julesburg (DJ) Basin, Colorado. The interpretations of fracture-hit signals at monitor wells yield insights into the fracture geometry and propagation across and within two targeted formations: Niobrara and Codell. We observe significant differences in hydraulic fracture propagation between the two formations; the half length of hydraulic fractures in the Codell formation is much longer than that in the Niobrara. In addition, hydraulic fracture propagates significantly faster in Codell than in Niobrara under the same pumping rate. The differences could be explained by higher natural fracture density and potentially lower stress anisotropy in the Niobrara formation. We also observed different fracture orientations between the two formations and inconsistent fracture orientations within Niobrara. Hydraulic fractures observed in Codell orient at 100 degrees consistently, while two groups of hydraulic fracture azimuths (110 and 240 degrees)  can be observed in Niobrara. The difference in fracture orientations in Niobrara and Codell indicates stress regime changes between the formations. The inconsistency of fracture azimuth within Niobrara may be caused by the zipper fracturing sequence. Strong cross-formation fracture connections between the two formations can also be observed, with LF-DAS signal signatures indicating high fracture connectivity between wells. Later analysis of production data indicates substantial cross-formation interference, which is consistent with cross-well strain interpretations. These observations help us better understand the complex fracture behavior in the DJ Basin and provide critical constraints on optimizing the unconventional reservoir development, including well spacing and completion designs.

Dr. Ge Jin is Assistant Professor of Geophysics and co-director of Reservoir Characterization Project (rcp.mines.edu) at Colorado School of Mines. His research mainly focuses on Distributed Fiber-Optic Sensing (DFOS) applications in Geophysics. He has been working on DFOS-related research projects since 2014 and has authored dozens of publications and patents in this field. He is also interested in machine-learning applications and seismic imaging. He currently leads a research group focusing on hydraulic fracturing monitoring and reservoir characterization using DFOS measurements. Dr. Jin obtained his Ph.D. in Geophysics from Columbia University in the City of New York, and dual B.S. in Geophysics and Computer Science from Peking University. He worked as a research geophysicist in the oil industry for five years before joining the university in 2019.