Coal and Petroleum (L23) Flashcards
the process in which coal is formed is a straightforward process of ______
pressing and gentle cooking of organic matter
where does the organic matter used to make coal come from?
land plants in a low-energy environment (like a swamp)
what slows down the further decay of the organic matter used to create coal?
an oxygen-free environment
what is peat?
a material made from the accumulation of organic matter
what type of coal is produced under diff levels of cooking?
little bit of cooking - a low-grade coal called Lignite
more cooking and pressing - Bituminous Coal (more compact black coal)
highest temp and pressure - Anthracite (high grade coal)
How was coal produced in the Paleozoic?
failed rift was produced from the Atlantic Ocean opening up and being bordered by swamps
What is Petroleum? and what is derived from?
petroleum is oil and natural gas derived from the remains of plankton
What are the oil and natural gases products of?
products of the chemical breakdown of the remains of various hydrocarbon compounds through absence of oxygen in organic rich-mud
what does this organic rich mud lithify into?
shale
What is Cracking?
the large complex molecules of oil and gas are broken down into smaller and shorter ones dominated by hydrogen and carbon due to conditions of increasing temperature with increasing depth
What is the oil window?
the temperature range in which most oil is produced between (60-120 degrees celcius)
what does wet gas refer to?
stuff that is liquid underground but a gas at the surface
What is dry gas?
more or less pure methane, gas both underground and at surface
What happens when oil and gas is unimpeded by an impermeable rock unit and why is it not good?
the oil and gas will continue to rise and emerge at the surface
not good, b/c it ends up being eaten up by microbes and oxidized
What is an Oil Trap?
a geologic environment that allows for economically significant amounts of oil and gas to accumulate underground
where are oil and gas contained in?
A reservoir
What is the key factor in oil traps forming?
it has to have a permeable reservoir unit that is overlain by an impermeable rock
Where do the fluids occur?
in all the individual pores and fractures within the reservoir rock
from bottom to top, the fluids always occur in this order:
water, overlain by oil, overlain by gas
What are stratigraphic traps?
traps whose characteristics are controlled by how the reservoir unit was deposited
What happens when the cap rock is punctured by drilling?
the oil and natural gas, under pressure, migrate from the pore spaces of the reservoir rock to the drill hole
before methods were developed to control the upward flow of oil in wells, what dangerous methods were used?
Blowouts (pressure explosions) and gushers (uncontrolled escape of oil)
What is Coke?
A spongy substance that is created from coal being heated in the absence of oxygen to remove gases
Where is coke burned in and why?
blast furnaces b/c it provides extremely high temps required for smelting process
