Geothermal Energy Resources from an Oil & Gas Perspective

For those more familiar with conventional oil & gas resources, it is convenient to make a comparison showing similarities and differences:

Oil & GasGeothermal Energy
– Source Rock – fine-grained sediments with sufficient amounts of organic matter, which generate and release hydrocarbons able to migrate upwards;Fluids – hydrocarbon oil & gas and water;Reservoirs – accumulations of hydrocarbons contained in porous or fractured rock formations (i.e. sandstone, limestone);Trap/Seals –structural or stratigraphic traps with cap rock seals preventing further hydrocarbon migration;Surface Indicators – oil & gas seeps / releases, acoustic plumes;Exploration – Geophysical (Gravity, 3D Seismic), Wells.  – Heat Source – volcanic/magmatic sources along plate boundaries; abnormally high heat flow from thinner crust areas; or granitic igneous intrusions;Fluids – mineralised water / brines or surface injected fluids;Reservoirs – Permeable Hydrothermal (wet, able to be produced and reinjected) or Fractured Rock (dry, natural or induced, able to have surface fluids injected and circulated);Traps/Seals – Thermal seals including impermeable rock;Surface Indicators – thermal gradients, hydrothermal features;Evaluation – Geophysical (AMT, Gravity, some Seismic), Wells.