Introduction to the thematic collection: Naturally Fractured Reservoirs
Naturally fractured reservoirs not only contain a significant share of the world’s hydrocarbon resources, they are also important to support the transition to a low carbon energy future, for example when producing low- and high-enthalpy geothermal heat or sequestering CO2. At the same time, these reservoirs present some of the most daunting challenges the energy industry is faced with. With a few exceptions, the rock matrix is generally responsible for the storage capacity of a reservoir whilst existing layer-bound and cross-layer fracture sets/corridors across a wide range of length scales define the characteristics of hydraulic connectivity (Ramsay & Huber 1987). In other words, flow in the reservoir (hydrocarbons, brine, or CO2), the ability to recover crude oil and gas (or geothermal heat), CO2 migration pathways, production profiles from wells, and the risk of bypassing oil and heat are greatly affected by the fracture network (Zimmerman & Bodvarsson 1996; Gale et al 2014).