Oil & Gas Unit 8: Natural Gas

What is the main component of natural gas?

Methane

What is conventional gas?

primarily methane found in a reservoir that does not extensive treatment for gas to flow to the surface

What is uncoventional gas?

Gas found in reservoirs such as shale or tight sand

What are examples of unconventional gas?

shallow (biogenically derived gas), deep gas, geopressurized gas (high pressure reservoir), coalbed methane (CBM), tight gas, shale gas, gas hydrates

What are sources of natural gas?

Gas fields, oilfields, coalbed methane (CBM), gas hydrates

What does CBM stand for?

Coal Bed Methane

What is Coal Bed Methane?

Methane that is adosrbed onto the solid coal matrix

Carbon from gas hydrates is conservatively estimated to total _____ the amount of carbon to be found in all known _________ on earth

twice, fossil fuels

Conventional natural gas production relies on the adequate ________ of the source rock

permeability

Unconventional natural gas is located in fields that were previously not _______, often with ____ permeability

accessible, low

What is tight gas?

A natural gas reservoir with low permeability

What does hydraulic fracturing (fracing) consist of?

Injecting a fluid made of water, a proppant (fine

-grained solid) and various chemicals into the formation at very high pressure

What is shale gas?

Natural gas in a shale reservoir

Why will shale not readily release gas?

The permeability of the shale is so low

What must be removed from natural gas before pipelining and use?

water and hydrogen sulfide

What kind of reaction is the scrubbing of hydrogen sulfide?

Acid-base reaction

What are the typical bases used in the scrubbing of hydrogen sulfide

alkanoamines

What kind of reaction removes Carbon Dioxide?

Acid-base reaction

What are the two-steps in the process of sweetening?

1) Gases dissolves in the liquid

2)Dissolved gas (weak acid) reacts with amines (weak base)

Hydrogen sulfide reacts via direct _____ transfer

proton

Why is water removed from natural gas?

low temp water can freeze is piping or form hydrates (methane hydrates), liquid water could condense

What is commonly used to absorb/adsorb water in the dehydration process?

glycols

What is the Claus Process used for?

To recover elemental sulfur from gaseous H₂S

What happens in the first step of the Clause Process and what is the reaction?

1/3 of the H₂S is partially oxidized

_{2H2S + 3O2 → 2SO2 + H2O}

What is the second step of the Claus Process and what is the reaction?

The remaining H2S is reacted with the SO2 formed in the first step over a catalyst

2H2S + SO2 ←> 3S + 2H2O + heat

What is the net reaction of the Claus Process?

H2S + ½ O2 → S + H2O

What process used methane to obtain hydrogen?

Steam Reforming

What happens in the first reaction of steam reforming and what is the reaction equation?

Methane is reformed with steam

H2O + CH4 → CO + 3H2

What is the reaction equation of the second reaction in the steam reforming process? What is this reaction called?

CO + H2O → CO2 + H2

Water Gas Shift Reaction

What is the net reaction of the steam reforming process?

CH4 + 2H2O → CO2 + 4H2

What does WGSR stand for?

Water gas shift reaction

What does WGR stand for?

Water Gas Reaction

What does LNG stand for?

Liquified Natural Gas

What is LNG?

Methane that has been processed to remove impurities and heavier components