Title: Transient Pressure Surge in a Fluid-Filled Fracture

Presenter: Assistant Professor Yingcai ZHENG

Institution: Department of Earth and Atmospheric Sciences, University of Houston

Time: 20180430-15:00:00

Location: Room 2829, No. 2 Science Building.

Abstract: Weak dynamic seismic stress waves from distant earthquakes can abruptly change the fluid permeability of a hydrologic system, trigger seismicity, or cause liquefaction. Many proposed mechanisms to explain these phenomena require a large fluid pressure gradient to induce fluid flow during the passage of the waves, yet the exact mechanism as to how the fluid pressure can change is unclear. Using full-waveform numerical modeling, we found that the transient seismic-wave pressure in a fluid-filled fracture could increase more than 2 orders of magnitude relative to the incident pressure. We call this transient pressure surge (PS). This pressure increase could be much more pronounced for low - frequency transient waves than for high frequencies and could develop a large pressure gradient to drive the fluid to flow. This PS phenomenon may be important for understanding many natural phenomena in fluid‐fracture systems.

Biography: Yingcai Zheng is an Assistant Professor in seismic imaging and reservoir characterization, in the Department of Earth and Atmospheric Sciences, at University of Houston. He also holds a joint faculty appointment in the Department of Physics, UH. Prior to his joining University of Houston in 2014, he was a Postdoctoral Fellow and Research Scientist at Earth Resources Laboratory at Massachusetts Institute of Technology. He got his Ph.D. in Geophysics from University of California Santa Cruz in 2007 and B.S. degree (2001) from Peking University, Beijing. He is a recipient of the SEG's 2015 Karcher Award for his contribution in exploration geophysics.

Reference: Zheng Y. Transient Pressure Surge in a Fluid-filled Fracture[J]. Bulletin of the Seismological Society of America, 2018.