ES Chapter 12/13

ENERGY

The capacity to do work.

BIOMASS

The amount of organic material in a specified volume.

FUEL

A substance that can be used to produce energy.

HYDROCARBON

A chain-like or ring-like molecule made of hydrogen and carbon atoms; petroleum and natural gas are these.

ENERGY DENSITY

The amount of energy contained by a unit volume of material.

SOURCE ROCK

A rock (organic-rich shale) containing the raw materials from which hydrocarbons eventually form.

KEROGEN

The waxy molecules into which the organic material in shale transforms on reaching about 100°C. At higher temperatures, it transforms into oil.

HYDROCARBON GENERATION

A process in which oil shale warms to temperatures of greater than about 90°C so kerogen molecules transform into oil and natural gas molecules.

OIL WINDOW

The narrow range of temperatures under which oil can form in a source rock.

HYDROCARBON RESERVE

A known supply of oil and gas held underground.

CONVENTIONAL RESERVE

A volume of oil or gas in a reservoir rock within a trap; it can be pumped relatively easily from the reservoir rock.

UNCONVENTIONAL RESERVE

A supply of oil or gas that cannot be easily pumped; it includes forms of hydrocarbons that are too viscous to pump, or occur in impermeable rock; examples include tar sand, oil shale, shale oil, and shale gas.

RESERVOIR ROCK

Rock with high porosity and permeability, so it can contain an abundant amount of easily accessible oil.

POROSITY

The total volume of empty space (pore space) in a material, usually expressed as a percentage.

PORE

A small, open space within sediment or rock.

PERMEABILITY

The degree to which a material allows fluids to pass through it via an interconnected network of pores and cracks.

OIL SEEP

A location where oil bubbles out of the ground on its own, without pumping.

SEAL ROCK

A relatively impermeable rock, such as shale, salt, or unfractured limestone, that lies above a reservoir rock and stops the oil from rising further.

SALT DOME

A rising bulbous dome of salt that bends up the adjacent layers of sedimentary rock.

SEISMIC-REFLECTION PROFILE

A cross-sectional view of the crust made by measuring the reflection of artificial seismic waves off boundaries between different layers of rock in the crust.

DRILLING MUD

A slurry of water mixed with clay that oil drillers use to cool a drill bit and flush rock cuttings up and out of the hole.

DIRECTIONAL DRILLING

The process of controlling the trajectory of a drill bit to make sure that the drill hole goes exactly where desired.

HYDROFRACTURING (FRACKING)

A process by which drillers generate new fractures or open pre-existing ones underground, by pumping a high-pressure fluid into a portion of the drill hole, in order to increase the permeability of surrounding hydrocarbon-bearing rocks.

DISTILLATION COLUMN

A vertical pipe in which crude oil is separated into several components.

SHALE OIL

Oil extracted directly from a source rock.

SHALE GAS

Gas extracted directly from a source rock.

TAR SAND

Sandstone reservoir rock in which less viscous oil and gas molecules have either escaped or been eaten by microbes, so that only tar remains.

OIL SHALE

An organic shale containing abundant kerogen.

COAL

A black, organic rock consisting of greater than 50% carbon; it forms from the buried and altered remains of plant material.

PEAT

Compacted and partially decayed vegetation accumulating beneath a swamp.

COAL RANK

A measurement of the carbon content of coal; higher-rank coal forms at higher temperatures.

COAL RESERVE

The quantities of discovered, but not yet mined, coal in sedimentary rock of the continents.

COAL GASIFICATION

The process of producing relatively clean-burning gases from solid coal.

NUCLEAR REACTOR

The part of a nuclear power plant where the fission reactions occur.

CHAIN REACTION

A self-perpetuating process in a nuclear reaction, whereby neutrons released during the fission trigger more fission.

MELTDOWN

The melting of the fuel rods in a nuclear reactor that occurs if the rate of fission becomes too fast and the fuel rods become too hot.

NUCLEAR WASTE

The radioactive material produced as a by-product in a nuclear plant that must be disposed of carefully due to its dangerous radioactivity.

BIOFUEL

Gas or liquid fuel made from plant material (biomass). Examples of biofuel include alcohol from fermented sugar, biodiesel from vegetable oil, and wood.

PHOTOVOLTAIC CELL

A device capable of transforming solar energy directly into electricity.

OIL AGE

The period of human history, including our own, so named because the economy depends on oil.

HUBBERT'S PEAK

The high point on a graph of production vs. time; the concept that we can define Hubbert's Peak for a resource emphasizes that supplies of resources are limited.

BLOWOUT

A deep, bowl-like depression scoured out of desert terrain by a turbulent vortex of wind.

ACID RAIN

Precipitation in which air pollutants have reacted with water to make a weak acid.

MINERAL RESOURCE

An economically valuable accumulation of a useful rock.

METAL

A solid composed almost entirely of atoms of metallic elements; it is generally opaque, shiny, smooth, malleable, and can conduct electricity.

ORE MINERALS

Minerals that have metal in high concentrations and in a form that can be easily extracted.

ORE

Rock containing native metals or a concentrated accumulation of ore minerals.

GRADE (OF AN ORE)

The concentration of a useful metal in an ore—the higher the concentration, the higher the grade.

ORE DEPOSIT

An economically significant accumulation of ore.

BANDED-IRON FORMATION (BIF)

Iron-rich sedimentary layers consisting of alternating gray beds of iron oxide and red beds of iron-rich chert.

MANGANESE NODULES

Lumpy accumulations of manganese-oxide minerals precipitated onto the seafloor.

DIMENSION STONE

An intact block of granite or marble to be used for architectural purposes.

CEMENT

Mineral material that precipitates from water and fills the spaces between grains, holding the grains together.

PORTLAND CEMENT

Cement made by mechanically mixing limestone, sandstone, and shale in just the right proportions, before heating in a kiln, to provide the correct chemical makeup of cement.

STRATEGIC MINERAL

A mineral containing elements, typically metals, of strategic importance to technology.