(520a) Enhancing Hydraulic Fracturing Productivity Via Model-Based Feedback Control

The term shale oil refers to natural oil trapped in rock formations of ultra-low permeability. Because of the low permeability of the shale formations, if a well were to be drilled into such a rock, it would take an extremely long time to reach an economically viable amount of production. What has made the recovery of shale oil economically viable, leading to the shale boom in the U.S. is the extensive use of two crucial technologies: hydraulic fracturing and directional drilling. Research on the relationship between proppant (i.e., propping agent) distribution and well performance indicates that uniformity of proppant bank height and suspended proppant concentration across the fracture at the end of pumping significantly affect the fluid conductivity, which is essentially the productivity, of fractured wells Specifically, in certain oil reservoirs, 10% difference in the propped fracture length from the desired value may cause 50% less oil production rate. However, no efforts have been made in improving the well performance via the regulation of the uniformity of proppant bank heights and suspended proppant concentration inside the fracture via real-time model-based feedback control of hydraulic fracturing, because of (a) large computational requirements due to the dynamic simulation of highly-coupled parabolic partial differential equations defined over time-dependent spatial domains, (b) spatial heterogeneity in rock mechanical properties such as the Young’s modulus, and (c) limited availability of real-time measurements and presence of uncertainties in the measurement data. Motivated by these considerations, in this talk, I will introduce a systematic, computational modeling and control framework for real-time model-based feedback control of hydraulic fracturing.