Chapter 18

Question 1

manufactured gas

Answer 1

aka Coal Gas, Town Gas. form of gaseous fuel derived mostly from coal. origin of natural gas. was a good way to provide lighting through dedicated pipes and also directly to consumers, back in the day. lighting then –> to electricity b/c cheaper and safer

Question 2

methane (CH4)

Answer 2

the lightest of hydrocarbons

natural gas tends to form in higher pressure and temp. ranges, resulting in a complete conversion of the organic matter into lighter hydrocarbons (methane)

Question 3

associated gas

Answer 3

natural gas that is found in conjunction with oil deposits

Question 4

flaring

Answer 4

burning of methane in flare stock, this must be dealt with for safety concerns – to avoid explosion or health consequences to oilfield workers

Question 5

therms

Answer 5

Therms = 100,000 BTUs (British Thermal Units)

measuring natural gas can be measured through energy content or by physical volume.

measuring nat gas often uses BTUs – the amount of energy needed to raise 1 pound of water by 1 degree F at a pressure of 1 atmosphere.

Question 6

unconventional gas

Answer 6

conventional = nat gas from associated and non-associated deposits.

unconventional = nat. gas trapped in geological formations like coal seams and shale rocks.

require advanced tech or non-traditional extraction methods to access

1. tight gas
2. shale gas
3. coal-bed methane

Question 7

tight gas

Answer 7

type of gas that is trapped in low permeability source rock deep underground. Gas is not freely flowing, see need well stimulation to break up gas from rock (hydraulic fracturing)

Question 8

hydraulic fracturing

Answer 8

using high-pressure water injection to break up source rock

a well-stimulation technique in which rock is fractured by a pressurized liquid. The process involves the high-pressure injection of ‘fracking fluid’ (primarily water, containing sand or other proppants suspended with the aid of thickening agents) into a wellbore to create cracks in the deep-rock formations through which natural gas, petroleum, and brine will flow more freely

Question 9

shale gas

Answer 9

natural gas trapped in even deeper/denser source rock and getting commercial quantities of nat gas requires more fracking + directional and/or horizontal drilling.

these wells usually have high initial production rates that drop off quickly w/o well stimulation

Question 10

horizontal drilling

Answer 10

drilling laterally across the source rock

as opposed to directional drilling, drilling at angles to follow hydrocarbon deposits

Question 11

coal-bed methane

Answer 11

shallower source of nat gas that is co-located with coal deposits. also coal-seam methane – stays trapped in the coal due to the presence of large amounts of water, creating pressure that prevents the gas from escaping upward through the rock.

extracting nat gas from these coal seams = usu. just removing the water – which allows pressure in reservoir to drop and then gas to escape

Question 12

initial production (IP)

Answer 12

This is the average amount of oil and/or gas produced over a specific time frame from a well.

The IP rate generally refers to the first 24 hours of the well, while the 90-day IP rate relates to the first 90 days.

Question 13

landfill gas

Answer 13

methane that’s captured from the decomposition of material in waste landfills.

trash deposit into landfills decomposes – creates substantial amounts of methane. this can be captured, purified, and injected into local nat. gas delivery infrastructure for distribution to homes/businesses

Question 14

biogas

Answer 14

created by breaking organic matter down with anaerobic bacteria in a digester – resulting in methane that can be used for thermal energy

most easily produced from agri. waste, unused plant material, or other farm/forest waste

Question 15

digester

Answer 15

a container in which substances are treated with heat, enzymes, or a solvent in order to promote decomposition or extract essential components.

biogas digester = biogas is created by breaking down organic matter with anaerobic bacteria in a digester. Result = methane that can be used for thermal energy

Question 16

Gas Initially in Place (GIIP)

Answer 16

estimates the total amount of gas in the reservoir based on seismic data and exploratory well experience

Question 17

recovery factor

Answer 17

% of the GIIP ultimately obtainable.

Question 18

casing

Answer 18

cement liners used to protect against the contamination of the surrounding soil and water – part of responsible drilling practices for natural gas

Question 19

produced water

Answer 19

water extracted from well

responsible drilling practices:

1. construct well pad/drill work site
2. set up drilling equipment
3. drill the wells
4. line the wells w/ casing
5. perforate casing in deposit zone to allow gas to flow into well
6. connect off-take equipment
7. remove waste material from site like produced water
8. remediate well site to conditions agreed to w/ resource owner

Question 20

raw gas

Answer 20

the gas that comes out of a well.

includes a number of hydrocarbons and other contaminants along with methane – must be removed to make pipeline-quality nat. gas (97% pure methane)

Question 21

pipeline quality natural gas

Answer 21

(97% pure methane) – low amounts of CO2 and other sulfides that would corrode pipeline infrastructure or present health risks to workers

Question 22

wet gas

Answer 22

liquid-rich gas that has a high concentration of NGLs (nat. gas liquids = ethane, pentane, butane) and condensate

As a result, has a rel. high energy content per volume.

Question 23

dry gas

Answer 23

has low concentrations of other hydrocarbons, requires less processing in order to bring it up to pipeline-quality natural gas

sometimes, the presence of high-value NGLs can help to improve the economics of nat. gas production, they are sold to help recover the cost of the production process

Question 24

compressed natural gas (CNG)

Answer 24

pipelines are usually used to transport oil and are effective at moving gas fro one place to another BECAUSE pipeline utilizes pipeline capacity effectively to achieve economies of scale by increasing flow rates through modest increases in the diamater of the pipes….

HOWEVER, moving gas through other methods like compressed in tanks or trucks as CNG is $$$$ and only economically useful for small volumes

Question 25

city gate

Answer 25

transmission of nat gas typically ENDS at the point it enters to distribution infrastructure – this is called the CITY GATE.

city gate prices = price paid at this point of entry into the distribution network, often used as a proxy for the delivered wholesale nat gas from the transmission system to very specific geography but BEFORE distribution charges and differential customer pricing takes over

Question 26

Federal Energy Regulatory Commission (FERC)

Answer 26

operating nat gas pipelines is subject to federal oversight – most of this authority belongs to FERC.

Once interstate pipeline is built, FERC regulates the operation and sets the max pricing of transmission svs to ensure fair and reasonable

Question 27

Local Distribution Companies (LDC)

Answer 27

nat gas has distribution characteristics of being a natural monopoly (like electricity).
LDCs manage the distribution service of nat gas.

similar to electricity system, there is investor-owned LDCs and publicly-owned municipal LDCs

Question 28

Fugitive emissions

Answer 28

emissions from the process of nat gas drilling and production processes

VOCs (volatile organic compounds)
methane (GWP of 86X that of CO2 over 20 years)

Fugitive emissions are emissions of gases or vapors from pressurized equipment due to leaks and other unintended or irregular releases of gases, mostly from industrial activities