Unconventional Resources from Exploration to Production

Abstract In this chapter we present an overview of unconventional resource evaluation and development. While different definitions have been proposed to classify unconventional resources, we consider here the subsurface hydrocarbon resources that are not conventionally developed to be unconventional reservoirs. These geological formations include tight gas sandstones, oil or tar sands, heavy oil, gas shales, coalbed methane, oil shales, gas hydrates, and other low-permeability tight formations. Among them, gas and oil shales and coalbed methane are typically source-rock reservoirs. We discuss general methodologies that may be more suitable to these source-rock reservoirs, but many of the workflows and development strategies apply to other reservoirs as well. A full development cycle of natural resources includes exploration, evaluation, drilling, completion, and production. We discuss methods and processes used in these development stages, as well as integrated workflows and pitfalls when evaluating and developing unconventional resources.

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