Mechanical and Civil Engineering Seminar: Special Seminar

Mechanical and Civil Engineering Seminar Series: Special Seminar

Abstract:

Hydraulic fractures are tensile fractures driven by pressurized fluid in a solid initially under compressive stresses. Examples of anthropogenic and natural occurrences in the upper earth crust abound from the stimulation of oil and gas wells to magmatic fissure eruptions. Under both normal and strike-slip stress regimes, they propagate vertically and their vertical extent is of prime importance in numerous cases (the presence of upper aquifers or the possibility of eruption are just two examples). In-situ stress & properties contrast between rock formations have been long recognized as the primary causes for their vertical containment at depth. In this talk, I will investigate additional effects. First, I will discuss the impact of the transverse isotropy of rocks on hydraulic fracturing growth combining theoretical modeling and laboratory experiments. Homogeneous transverse isotropic properties promote vertical containment, but such a containment is function of the ratio between the energies dissipated in fluid viscous flow versus fracture surfaces creation. In a second part, I will clarify the importance of the buoyancy contrast between the solid and fracturing fluid on the propagation of three-dimensional hydraulic fractures in a homogeneous material. How material properties and in-situ stress contrast can stop the vertical growth of an otherwise self-buoyant hydraulic fracture will then be quantified in the light of fully coupled numerical simulations.

Bio: Professor Brice Lecampion is the head of the Geo-Energy Lab – Gaznat chair at Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland. His research aims at understanding the interplay between the growth of localized discontinuities (in the form of fractures and faults) and fluid flow in geomaterials with applications in the field of environmental, geothermal, civil engineering, seismology and tectonophysics. Brice previously worked for Schlumberger Ltd from 2006 to 2015, holding a number of different positions in research and development from project manager to principal scientist both in Europe and the United States, working notably on CO2 geological storage integrity and well stimulation technologies. Dr Lecampion received his PhD in mechanics from Ecole Polytechnique, France in 2002 and worked as a research scientist in the hydraulic fracturing research group of CSIRO division of Petroleum resources (Melbourne, Australia) from 2003 to 2006.

NOTE: At this time, in-person Mechanical and Civil Engineering Lectures are open to all Caltech students/staff/faculty/visitors.