Transcript File

Helium PBL
What is Helium, where is it made,
and where can we find it?
What is Helium?
• The atomic number of
helium is 2, meaning each
atom of helium has two
protons.
• Helium has the lowest
melting point and boiling
point of the elements, so
it only exists as a gas
except under extreme
conditions.
• Helium is the secondlightest element.
More on helium
• Helium is also the second-most abundant
element in the universe, though it is much less
common on Earth.
• Helium is colorless, odorless, tasteless, nontoxic, and inert.
• Helium is the second-least reactive noble gas
(after neon).
• Thinking of these facts, why is it so difficult to
store helium when it is found?
Where is helium made?
• Helium is made by
fusion (In Stars)
• Helium is made by
fission (decay) Earth
What elements produce helium?
• Helium is known to be produced by the decay of
various radioactive elements, principally;
• Uranium
• Thorium
• Radium
• With Uranium being the highest production rate of
2.75X10-5 [g/(year)(mm3)]
• Argon and Radon are by-products of the radioactive
disintegration of potassium and radium, respectively,
and are believed to have an origin similar to that of
helium.
Facts about Argon and Radon
• Helium has economic significance, is inert and
safer then hydrogen.
• Argon and Radon do not have economic
significance
• However Radon is considered an
environmental hazard, because inhalation can
cause cancer.
• Radon hazards are higher in areas of
basement, and granites in particular.
Where is helium found on Earth?
• Most helium is obtained by extracting it from natural
gas
• Helium is a common minor accessory in many natural
gases
• Helium occurs in the atmosphere at 5 ppm and has
also been recorded in mines, hot springs and fumaroles
• It has been found in oil field gases in amounts up to 8%
• In North America helium-enriched natural gases occur
in the Four corners area and Texas panhandle of the
United States
More areas of helium production
• In Canada the major concentrations along
areas of crustal tension, such as the Peace
River and Sweetwater arches
• It is also found in the foothills of the Rocky
Mountains
How much and where
• Between 282 to 1.06 billion cubic feet of helium
is generated from the decay of various
radioactive elements
• Based on this data the helium found in natural
gas is widely believed to have emanated from
deep-seated basement rocks, especially granite
• Although the actual rate of production is slow
and steady, the expulsion of gas into the overlying
sediments cover may occur rapidly when the
basement is subjected to thermal activity or
fracturing by crustal arching.
Continued
• The correlation between basement rocks and
helium production is difficult to establish
because helium tends to occur in deep, rather
than shallow wells, and there is seldom
sufficient well control to map the geology of
the basement.
• Helium also occurs from the breakdown of
uranium ore bodies within sedimentary
sequences (Castlegate, Central Utah)
The Texas Fields
• The major source of helium in the United
States is the Panhandle Hugoton field in Texas
• This field locally contains up to 1.86% helium
• This field is significant because it produces
helium from sediments pinching out over a
major granitic fault block
Panhandle Hugoton field in Texas
Geologic cross section
Walther’s Law
• A law stating that lithologies that
conformably overlie one another must
have accumulated in adjacent
depositional environments.
• Another way of thinking of this is the
ability to predict what the rock units will
look like if the depositional environment
changes.
Here is the castlegate sandstone in Utah,
does this cross-section look familiar?
How could yourself or your team use
Walther’s Law to find deposits or storage
sites?
• Take 3 minutes to brainstorm with you team
members and come up with at least two ways
in which this law will help your team solve the
problem.
If Yellowstone Could Talk, It Might
Squeak. Blame The Helium
A huge amount of ancient helium is rising up from the
rocks beneath Yellowstone National Park — about
enough to fill up a Goodyear blimp every week.
The gas comes from a vast store of helium that's
accumulated in the Earth's crust for hundreds of millions
of years, scientists report in the journal Nature this week.
The helium is being released because in the past couple
of million years — very recently, in geologic time — that
old part of the crust has been feeling the heat from a
huge volcano that is now sleeping underneath the park.
If Yellowstone Could Talk, It Might
Squeak. Blame The Helium
Usually, volcanoes form at the edges of the tectonic
plates that make up the Earth's crust. "It's a part of the
crust that formed a very long time ago, billions of years
ago, and it's basically been stable since that time,“. A
plume of molten rock from deep within the Earth has
been pushing up into these old rocks.“ They've had this
boring, peaceful existence and now suddenly they're put
on the front burner, They're really getting cooked. "All
that cooking is driving out helium that's been trapped
inside the rock for a long time. The finding came as a
surprise to scientists who look for clues about what's
happening beneath Yellowstone by collecting the gases
that bubble up.
If Yellowstone Could Talk, It Might
Squeak. Blame The Helium
We had sort of an 'Aha' moment where we realized, wow, that
there's a lot of crustal helium coming out of Yellowstone — far
more than we would have predicted," referring to a type of
helium produced by the radioactive decay of elements in the
Earth's crust. As the researchers report in Nature, the amount
being released by the rocks below Yellowstone is prodigious.
"It's kind of an interesting thought to us, how these rocks
behave," Evans says, "because it's very rare on the face of the
Earth to have vulcanism come into rocks that have been that
stable for that long.“
Even if Yellowstone weren't a protected national park, it
wouldn't be economically practical to try to collect the gas —
so don't expect to someday be blowing up party balloons with
helium from Yellowstone