A suite of benchmark and challenge problems for enhanced geothermal systems

Study of mixed mode fracture toughness and fracture trajectories in gypsum interlayers in corrosive environment

“…It is also an inherent attribute of a material, independent of shape and loading conditions of the specimen. Most studies on the fracture toughness of rocks were focused on mode I because the opening mode failure is frequently encountered [1][2][3][4][5][6]. However, due to the randomly distributed cracks, faults, joints and natural weak plane, actual cracks in rock blocks are often subjected to combined loading, and occur not only in tension but also in shear.…”

Recent comprehensive review for extended finite element method (XFEM) based on hydraulic fracturing models for unconventional hydrocarbon reservoirs

“…Enhanced Geothermal System (EGS) or Hot Dry Rock (HDR) geothermal system as formerly known was pioneered at Los Alamos National Laboratory, New Mexico, USA in the 1970s (Barbier 2002;Xia et al 2017). In EGS, a pair of wells are drilled to a depth where rock temperatures approach 300C (White et al 2017). The wells are then hydraulically fractured, thus creating a connection between the wells.…”

“…In another method, the heated fluid exchanges heat with a working fluid, which will turn into vapour during the heat exchange process and it will drive the turbine. The cooled fluids are then re-injected into the thermal reservoir or cooled further in a secondary recovery system (White et al 2017).…”

Heat-capacity measurements of sandstone at high temperatures

“…Modeling of heat flow in the host rock requires accurate representation of thermal properties of the specific rock materials. The main goal of any geothermal energy production system (Teke and Yaşar 2018;White et al 2018) is to extract heat from the earth, and to extract it at a high enough temperature and rate that it can be used commercially to generate power or process heat. To evaluate the geothermal energy production technology (extraction of heat from hot dry rock) we must predict the amount of heat present and the rate at which it can be extracted.…”

“…Temperature is one of the most important factors affecting the heat capacity and other thermal properties of rock materials. There are number of other useful applications of the heat capacity of rocks such as: (1) Petroleum and natural gas geology (thermal methods enhanced oil and gas recovery technology; petroleum and natural gas economics; origin and accumulation of petroleum and natural gas; petroleum and natural gas geochemistry; reservoir engineering; thermodynamics and phase behavior in porous media, Boberg 1988;Burger et al 1986;Butler 1991) ; (2) utilization of hydrothermal energy (Waples 1994;Schön 1996;Č ermak and Rybach 1982;Teke and Yaşar 2018;White et al 2018) and underground thermal energy storage; (3) applications to geothermal problems, geothermal gradients and heat flux through the earth's crust (mathematical modeling), hydro-geological studies (rock mechanics/petrophysics, drilling and drilling fluids, well logging, testing and evaluation, fluid mechanics in porous media and multi-phase flow; reservoir simulation). All these processes are requiring accurately knowledge of the thermophysical properties (C P , k, q) data of dry and fluid-saturated porous rock materials as a function of temperature, pressure, and porosity.…”