Here’s an example of an Oil reservoir with a Gas cap
Gas
Oil
Water
Why do you suppose the gas is on top?
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How do we find the oil reservoirs?
(For example, we know that present day garbage dumps give off methane gas)
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What else do we know about oil and gas?
Oil in it’s natural state can be thick
Exploring and Drilling for Oil and Gas
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What are Oil and Gas?
• Oil and Gas are substances found within the earth’s crust. • They are thought to come from decomposed plant and animal matter. • Scientists believe the plants and animals died long ago, and were slowly buried by thick layers of sediments. Over a long period of time, and with pressure and temperature, the organic materials were converted into the oil and gas which are found today.
That’s enough gas in a single barrel of oil to
fill your whole house!
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Where can we find Oil and Gas?
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Some people think that oil is in big pools underground.
Drill ships and semi-submersible rigs are for drilling in water depths from 100 to 5000+ ft.
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What’s a drilling rig ?
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So, how do we find oil-bearing rocks?
• Oil and gas are found in natural traps within the earth. • These traps consist of domes or faults. Impermeable rock above the trap prevents the oil and gas from migrating up to surface. An “impermeable” rock is one that fluid cannot pass through. • without traps, the oil and gas could migrate all the way to the surface and evaporate.
The drill string is turned at surface, which turns the bit at the bottom of the hole.
Drilling mud is pumped down the inside of the drill pipe, through jet nozzles in the bit, and into the “annulus”. This is the space between the sides of the hole and the drill pipe.
A Drilling Rig is:
A package of special equipment put together to enable us to
drill into the earth.
• A drilling rig has many different parts: a derrick, a substructure, hoisting equipment, engines for power, drill pipe, steel tanks, pumps, solids control equipment, and many other pieces.
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Here’s an example of a Gas reservoir.
Gas Water Again, note the impermeable layer of rock preventing the gas from escaping.
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Jackup Rig Land Rig For drilling in water depths from 15 ft to +/- 350 ft.
For drilling on land.
Inland Barge
Drill Ship
Semi-Sub`mersible Rig For drilling in water depths from 8 to 30 ft.
• Did you know that some drilling rigs can drill as deep as 6 miles? That’s as deep as Mt. Everest is tall!
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This picture shows the hoisting equipment on a rig.
The teeth on the drill bit grind the rock into fragments, or “cuttings”.
The mud lifts the cuttings and circulates them back to surface where they are removed.
• Geophysicists find reservoirs by bouncing sound waves off them, and timing how
long it takes for the sound to come back
• Computers process the data to construct pictures of what the earth looks like
Actually, most oil is trapped in the tiny pore spaces between
grains of rock or sand. Most of these pores are too small to be seen with the naked eye.
Prepared by Tom Sheeran
or thin, black or light colored.
When oil is refined, many products
can be obtained:
Many other materials also come
• • • • • Energy for power Gasoline for cars `Diesel fuel for trucks and trains Hi-`octane fuels for planes Heating oil for houses from pe`troleum: • Plastics • Materials for clothes (example: poly`ester fabrics) • Chemicals for everyday use • Paints
This equipment is used to raise or lower the drill string, which is picked up in 30 foot long segments, or “joints”, of drill pipe.
The hoisting equipment consists of: a crown block, a traveling block, drilling line, and a drawworks to pull the drilling line up or down. substructure Drill string Drill bit spare drill pipe
carbon dioxide which is put inside of pop to give it its fizz.
A barrel of oil may contain anywhere from
1 cubic ft of gas, to over 10,000 cubic ft, depending on the type of reservoir.
underground.
source t = 1 sec
t = 1.2 sec
t = 1.42 sec
receivers
Gas Oil
Prepared by Tom Sheeran