Abstract

Shale gas is an unconventional fossil energy resource that is already having a profound impact on US energy independence and is projected to last for at least 100 years. Production of methane and other hydrocarbons from low permeability shale involves hydrofracturing of rock, establishing fracture connectivity, and multiphase fluid-flow and reaction processes all of which are poorly understood. The result is inefficient extraction with many environmental concerns. This work uses innovative high-pressure microfluidic and triaxial core flood experiments on shale to explore fracture-permeability relations and the extraction of hydrocarbon. These data are integrated with simulations including lattice Boltzmann modeling of pore-scale processes, finiteelement/ discrete element models of fracture development in the near-well environment, and discrete-fracture network modeling of the reservoir. The ultimate goal is to make the necessary measurements to develop models that can be used to determine the reservoir operating conditions necessary to gain a degree of control over fracture generation and fluid flow.

1. INTRODUCTION

Shale gas is an unconventional fossil energy resource that is already having a profound impact on US energy sector, with reserves projected to last for nearly 100 years [1]. The increased availability of shale gas (i.e., methane), which produces 50% less CO2 than coal, is primarily responsible for US emissions in 2011 dropping to their lowest levels in 20 years [2]. Production of methane and other hydrocarbons from low permeability shale involves hydrofracturing of rock, establishing fracture connectivity, and multiphase fluid-flow and reaction processes, all of which are poorly understood. The result is inefficient extraction with many environmental concerns [3,4]. Industry is motivated to reduce the 70 to 140 billion gallon per year water demand because there are droughts in the west, a lack of deep injection wells in the east, and possible forthcoming regulations [3]. Our goal is to use unique Los Alamos National Laboratory (LANL) microfluidic and triaxial core flood experiments integrated with stateof- the-art numerical simulation to reveal the fundamental dynamics of fracture-fluid interactions to transform fracking from an ad hoc tool to a safe and predictable approach based on solid scientific understanding. The goal is to develop CO2-based fracturing fluids and fracturing techniques to enhance production, reduce waste-water, while simultaneously sequestering CO2 [4].

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