Chapter 4 Flashcards
What is the difference between resources and reserves?
Resources
Known or hypothetical concentrations that can now or in the future be developed as energy sources.
Reserves
Estimated quantities that engineering or geological analysis demonstrate to be producible under current economic operating conditions.
What are fossil fuels and how are they form
Fossil fuels (oil, gas, coal) are hydrocarbons formed from ancient organisms. Oil and gas are from micro-organisms, while coal is from plants. They require rapid burial in low oxygen, compaction, and heat to form.
What is a source rock in petroleum geology?
A source rock is an organic-rich rock, mainly mud that has transformed into shale (oil shale), where oil and gas form through heat and pressure.
What is kerogen and how does it relate to petroleum?
Kerogen is a complex solid formed from organic matter in shale. With increasing temperature and depth, it matures into oil and gas.
How do oil and gas molecules differ?
Gas molecules are small chains (1–4 carbon atoms). Oil molecules are larger chains (15–60 carbon atoms) or rings, making them more complex.
What is primary migration in petroleum systems?
Primary migration is the movement of petroleum from the source rock to a porous and permeable reservoir rock.
Define porosity and permeability.
Porosity is the amount of empty space in a rock. Permeability is the connectivity of those spaces that allows fluids to move through.
What are structural and stratigraphic traps?
Structural traps are formed by tectonic activity (folds, faults). Stratigraphic traps form by erosion or changes in rock types (pinch-outs, unconformities).
How is coal formed from peat?
Peat is buried, compacted, and heated over time, losing moisture and volatiles, transforming into coal.
What’s the difference between coal rank and coal grade?
Rank measures heat content based on %carbon (BTU). Grade measures purity, focusing on sulfur and ash content.
Name 5 types of renewable energy sources.
Geothermal, Tidal, Hydropower, Wind, and Solar energy.
How is geothermal energy generated?
In volcanic or radioactive regions, groundwater is heated to steam by subsurface heat and used to power generators.
What is an aquifer and water table?
An aquifer is a porous rock layer that stores groundwater. The water table is the top level where all pore spaces are filled with water.
What is the difference between confined and unconfined aquifers?
Unconfined aquifers can rise and fall freely with recharge. Confined aquifers are trapped under impermeable layers controlling the water level.
Why is solar energy challenging to use?
Solar energy is only available during the day. Systems must store energy or use backups for night use.
What is the percentage of renewable energy used?
7%
