ABSTRACT: The greatest technical breakthrough in oil and gas production in the United States over the past 20 years was the successful exploitation of unconventional (shale) reservoirs with horizontal wells and hydraulic fracturing. One way to derive insight into how best to create effective surface area for production in the reservoir is through laboratory fracture experiments and numerical fracture modeling. I will review some of the lessons learned in my research group about hydraulic fracture - natural fracture interactions from small-scale hydraulic fracture injection experiments in synthetic rock and from tensile crack propagation experiments in Marcellus shale. The work focuses on how cemented natural fractures can divert natural fractures and cause hydraulic fracture network complexity. I will also describe our computationally efficient numerical modeling approach to simulate complex hydraulic fracture network development from horizontal wells. Our goal is to put just enough physics into the model to get reasonably accurate results but to also incorporate enough simplifications such that the model can be efficiently run. Fast computation allows us to employ our model using optimization techniques that require 10’s or 100’s of simulation iterations. Preliminary optimization results on perforation cluster spacing are consistent with work by others suggesting irregular spacing can produce greater created surface area in the reservoir. Other optimization results suggest adjusting rate can improve results, as well as indicating an optimal number of clusters per stage to maximize created surface area.

Bio: Dr. Jon E. Olson is a professor and the department chair of the Hildebrand Department of Petroleum and Geosystems Engineering at The University of Texas at Austin. Dr. Olson has been at UT-Austin for more than 25 years, before which he spent 6 years working on hydraulic fracturing and reservoir geomechanics for Mobil Research and Development Corporation at their Dallas Research Lab. He has BS degrees in civil engineering and geology from the University of Notre Dame, and a PhD in structural geology and geomechanics from Stanford University. He has published on fracture and geomechanics related topics in both structural geology and petroleum engineering. He has been a Distinguished Lecturer for both AAPG and SPE, and is a Distinguished Member of SPE. As department chair, his current focus is on how to successfully adapt an oil and gas oriented academic program to excel in the coming energy transition, and to promote technologies that supply sustainable, reliable and abundant energy to the world.

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