Introduction to

Gas Transportation

By Puput Aryanto Risanto

22 December 2016

Oil & Gas Industry

Upstream Midstream Downstream

Finding, lifting, and

processing oil & gas

from subsurface into

surface and ready for

transportation. Also

known as Exploration

and Production (E&P).

Transportation and

storage of crude oil

and natural gas from

E&P plant for further

processing by

pipeline, railway, road,

or tanker.

Processing of crude oil

and natural gas into

useful final product or

raw material for other

industry. Also known as

Refining & Marketing

(R&M)

Gas Dilemma

• In the early history of oil industry, natural gas in

considered by-product (waste) during drilling

attempt for searching oil. Only gas found during

drilling is considered failure since gas is flammable

and cannot be processed & stored. and cannot be processed & stored.

• Gas can only be contained in a pipe and burnt

immediately in a safe place, either for heating,

boiling water, or burnt for nothing, known as flare.

Oil in Alberta on 1950 Canadian postage stamp,

showing two drilling derricks, storage tanks, and

flaring of "waste" gas,1914 - 1918 era.

Gas Problem

• Not like crude oil which is liquid in room temperature (25oC

/ 77oF) & atmospheric pressure (1 atm / 101,325 Pascal /

14.7 psi), natural gas is gaseous state in room temperature

& atmospheric pressure.

• Gas has lower density than oil, meaning in a same volume,

gas has lower mass & energy density.gas has lower mass & energy density.

• In room temperature & atmospheric pressure, gas will

occupy very large space, hence it’s not practical &

economic to store gas in this state.

• Since can’t be stored naturally, gas must be used or

transported immediately if required in other place.

• Gas delivery must match requirement, excess gas can only

be flared (burnt) or vented (released to atmosphere).

Ideal Gas Equation

• Behaviour of gas in many condition can be

described in Ideal Gas Equation

pV = nRT or V = (nRT) / p

• Where p = pressure, V = volume, n = gas • Where p = pressure, V = volume, n = gas

amount (number of mole), R = ideal gas

constant, and T = temperature.

• It means to reduce Volume, we must

reduce Temperature or increase Pressure

(or both) since n is given and R is constant.

Gas Value

• Despite all known problems, gas has several advantages

over oil or coal, i.e. :

– Cleaner fuel (less emission) for power plant & vehicle

– Cheaper than oil-based fuel, i.e. gasoline

– Can be used as a feed stock / raw material of – Can be used as a feed stock / raw material of

petrochemical industry like fertilizer

• With all above advantages, gas demand slowly grows and

oil company start thinking to monetize its gas reserve.

• Gas must be transported from the wellhead to the

customer to bring value to the producer.

• Gas company shall regulate the volume to match

customer requirement while minimizing wasted gas.

Gas Monetization

• To bring the optimum value of gas, method of gas

transportation & storage becomes very critical.

• Remember, as per ideal gas equation, gas must be

compressed and/or cooled to reduce the volume.

• Gas can also be converted into another form and

transported in the new form.transported in the new form.

• The technology used to reduce the gas volume or convert

into another form will depend mainly on the gas delivery

volume and distance from gas producer to gas consumer.

• However, it will also depend on the price, consumer

requirement, and technology maturation.

Gas Transportation Technology

Technology Vol Reduction

Pipelines 70-100

CNG 250-300

LNG 600

Hydrated 150-200Hydrated 150-200

CNG : Compressed Natural Gas

LNG : Liquefied Natural Gas

GTL : Gas To Liquid

GTW : Gas To Wire

Technology Selection

GTL LNG and/or GTL

• Pipeline is the

traditional, well proven

method and the most

economic for short

distance

• LNG is used for large

volume gas in a very volume gas in a very

long distance

• CNG is used when the

volume is not economic

enough for LNG

• GTL is the most

advance method to

convert low value gas

into high value liquid,

hence small volume can

be made economic

Pipeline

• Pipeline is a long pipe for conveying fluid (oil, gas,

water, etc) over long distance.

• Gas must be compressed by a gas compressor in

order to be able to receiving point.

• Pipeline is only for gas transporting, even tough • Pipeline is only for gas transporting, even tough

sometimes it is used as “gas temporary storage.”

• Gas compression ratio in a pipeline depends on

the gas volume delivery, distance, inlet pressure

and required pressure on the receiving point.

Gas Booster Station

• If the distance is very long, a gas compressor

might be placed between pipeline section known

as booster compressor

Multi-stage booster pump, use the same principle like booster compressor

Compressed Natural Gas (CNG)

• Gas is compressed up to 20-25 Mega (million)

Pascal / 2900-3600 psi and stored in a hard tank,

normally in cylindrical or spherical shape, known

as CNG (Compressed Natural Gas). CNG only

occupy less than 1% of space compare to volume occupy less than 1% of space compare to volume

in atmospheric pressure.

• CNG can be transported via road & sea, and can

be easily used by reducing its pressure.

• However, for large quantity over long distance,

CNG is considered not economical.

CNG transportation

CNG transportation

concept vessel

(enersea.com)

CNG distribution CNG distribution

truck

Liquefied Natural Gas (LNG)

• In this method, gas is cooled down to -161oC / -

256oF at atmospheric pressure till condenses to a

clear, colorless, and odorless, liquid know as LNG.

• This liquefaction reduce the volume by 600 times,

makes it very economic for large volume makes it very economic for large volume

transportation over very long distance.

• Natural gas must be purified to contain only

methane and ethane (or 100% methane) before

supercooled to form LNG.

• LNG will be converted back to a gas form in the

receiving facility, known as regasification terminal.

LNG process diagram

LNG process diagram at PT Badak NGL, Bontang, Indonesia

LNG value chain

Gas To Liquid (GTL)

• Many confusion the difference between GTL and

LNG since both contain “Liquid & Gas” term.

• While LNG is a physical reaction to convert natural

gas (methane) in a gas form to a liquid form, GTL

is a chemical reaction to convert natural gas is a chemical reaction to convert natural gas

(methane) in a gas form to a different, more

complex, and valuable substance in a liquid form.

• GTL process is much more complex and costly,

hence not much GTL plant in the world compare to

LNG plant.

GTL definition & history

• A chemical process to convert natural gas into

synthetic liquid (can be crude oil, diesel fuel,

aviation fuel, or gasoline) through Fischer-Tropsch

(FT) process.

• Originally invented in early 1920 by German • Originally invented in early 1920 by German

chemist Franz Fischer and Hans Tropsch in

Germany which later on used by the Germany

during World War II.

• Highly exothermic (produce a lot of heat) which

can be used to generate steam or power.

GTL process

• Major steps in GTL process :

� Remove impurities such as mercury & hydrogen sulphide

� Produce synthesis gas from Natural Gas and Air / Oxygen.

� FT synthesis to convert synthesis gas to long chain, heavy

paraffinic liquid. Paraffin is a mixture of high-molecular-

weight alkanes (i.e., saturated hydrocarbons with the

general formula CnH2n+2, where n is an integer).

• Byproducts is large amount of water and small amount of

CO2, olefins, oxygenates, and alcohol.

Simplified GTL block diagram

GTL can

convert

natural gas

into more

valuable liquid

like kerosene,

gasoline, and

LPG.

Conversion

ratio is about

10 thousand

of cubic feet

(mcf) raw gas

into 1 barrel

liquid product.

Gas To Wire (GTW)

• GTW is a term of converting gas into electricity in a location

close to (or even on top of) a gas field and transfer the

electric power to the customer via transmission and

distribution lines.

• Gas is used as a fuel of gas turbine (or gas engine in a

small scale) driving a power generator.small scale) driving a power generator.

• In a large scale, waste heat from a gas turbine can be used

to convert water into steam to turn steam turbine connected

to other or same power generator. This configuration is

known as Combined Cycle Gas Turbine Power Plant.

• Technical-commercial evaluation must be carefully

conducted whether building power plant close to gas field

(GTW) or transfer gas to power plant close to consumer.

Combined Cycle Gas Turbine

1. Air is compressed

in a compressor,

then mixed with the

gas fuel

2. Combustor ignites

air-gas mix, then

turn the gas turbine

3. Hot excess gas 3. Hot excess gas

convert water into

steam in a Heat

Recovery Steam

Generator (HRSG)

4. Steam turns steam

turbine

5. Both gas & steam

turbine drive single

generator to

produce electricity

Simplified CCGT Power Plant block diagram

Methane Hydrate

• Methane hydrate / gas hydrate / methane ice / fire ice /

methane clathrate is a solid clathrate (chemical substance

consisting of a lattice that trap molecules) in which large

amount of methane (the biggest portion of natural gas) is

trapped within crystal structure of water, forming a solid

similar to ice. similar to ice.

• It is found naturally under sediments on the ocean floor.

• Method to transfer natural gas in the form of methane

hydrate is still under experiment, yet to commercialized.

Gas Sales Agreement (GSA)

• Due to high investment of gas production facility, long term

gas sales agreement must be established first prior to gas

field development.

• Normally, agreement must exist for at least 10 years.

• The most critical factor is gas price calculation.

• Gas price depends on field complexity, gas delivery • Gas price depends on field complexity, gas delivery

volume, sales period, seller economic criteria, buyer

capability, and local law & regulation.

• Gas price may be fixed over sales period, but normally it is

a function of oil price with floor (min) price to protect seller

and ceiling (max) price to protect buyer.

• That’s why, not like oil price which is same for similar oil

quality, gas price can vary even for the similar gas quality.

Thank You Thank You Thank You Thank You –––– TerimaTerimaTerimaTerima KasihKasihKasihKasih

Petronas FLNG Satu (PFLNG Satu)

The world first Floating LNG on stream

About the Author

Puput Aryanto Risanto, PMP is a Project Management Professional certified Sr. Project Engineer with 12+ years experience in oil & gas industry. Currently he is working for Premier Oil Natuna Sea B.V. in Jakarta, Indonesia. Previously he worked for PetronasCarigali Sdn. Bhd. in KL, Malaysia, Premier Oil Carigali Sdn. Bhd. in KL, Malaysia, Premier Oil Natuna Sea B.V. in Jakarta and Total E&P Indonesie in Balikpapan, Indonesia.

His expertise includes project engineering & management,

joint venture management, engineering & construction

management, & electrical engineering-construction-

inspection. He can be contacted at email

aryantorisanto@yahoo.com or linkedin Puput Aryanto Risanto.