Talk:Natural gas

Chemistry/Physical Properties

This page definitely needs some technical specifics, such as the methane, propane, etc. pages have. For instance what is the composition by percentage (ranges)? Is this before processing or what is piped to consumers (perhaps removal of propane, etc.)? Why is it used vs. methane or propane? What is the cost vs. methane, ethane, etc? What temperatures does it produce when burned in air? What about when burned in oxygen?

NG is specified by its bulk heating value, not chemical composition. This is done by the Wobbe index and as such, nearly any light HC species (C3 and under) can be diluted to match methane as long as it does not condense at the pipeline pressure. For example, LPG can be dilluted 60/40 with air to make synthetic natural gas, used for peak demand times. Because of this fungability, prices for LPG track NG. Ethane is typically more valuable as a feedstock for petrochemical industry.

The reason propane and butane are removed from commercial pipelines is pressures typical of these lines (30 Bar) would cause these heavier components to condense. NG pipelines cannot tolerate liquids (two phases in any pipeline cause "slugging") so these condensing species are removed. I think that we should stick with renewable energy.

It would be helpful if the natural gas page contained more information on the byproducts of natural gas combustion: CO2? Lethal or hazardous components? 76.105.140.218 19:03, 25 October 2007 (UTC)

Why is there no discussion of the chemical formulae for different kinds of natural gas?

Is natural gas always a fossil fuel? If some natural gas is not fossil fuel, what natural processes are involved in that production?

What about the existence of natural gas or the prospect of it on other planets, planetoids or moons? I saw a television show (The Universe? maybe) recently that claimed one of the moons of the outer planets in our solar system had oceans of natural gas. How did it get there as there was obviously no biological basis (fossil fuels) as is the case on Earth. That was the question that sent me here looking for some basic answers. —Preceding unsigned comment added by 76.105.118.110 (talk) 02:41, 26 April 2009 (UTC)

Gas reserves in the North Field

You may be mistaken about gas reserves in the North Field. My info comes from a geologist who's been working on the field in Qatar for a decade or so. 22:09, 17 July 2007 (UTC)

We have to go with what we can source, however. I'm just working with what references I have found (Wikipedia articles cannot be used to reference other Wikipedia articles, unless there is a solid citation available - the ones you linked to list the larger amount but have nothing to prove it, whereas the smaller amount is sourced from third-party sites.) --Ckatz^chat_spy 22:11, 17 July 2007 (UTC)

Is there any chance your contact can point the way to published sources confirming the larger number? It would be great to have that information if such a source is available. (And a good find on your part!) --Ckatz^chat_spy 22:18, 17 July 2007 (UTC)

The figures given for Russia and Qatar fields are written in a slightly different way, so they are not very comparable- plus I don't understand the difference between gas fields and proven reserves. IceDragon64 (talk) 14:25, 20 July 2009 (UTC)

Odour

Is the odour addition thing US-specific? Whilst I wouldn't call the gas I get in the UK odourless, it certainly isn't foul-smelling and the smell is a distinctly 'gas' smell... something that I don't associate with anything else.

LaFoiblesse 2008-07-27 14h56 (GMT)

The natural gas I have at my house here in the U.S. smells about the same as the gas cooker we used to have in Norway when I was a kid (on camping trips). It isn't outright "foul" smelling except in large doses or up-close. My guess is that different jurisdictions or gas companies choose their own methods and for the sake of safety typically choose something unsettling. —Preceding unsigned comment added by 71.71.206.136 (talk) 02:23, 15 October 2008 (UTC)

I know NW Natural Adds A "Rotten Egg" smell they even had a commercial about it and how they could add any smell they want but add "Rotten Eggs" for safety Speer320 (talk) 02:43, 15 October 2008 (UTC)

Storage and transport

Storage Most natural gas is NOT stored in caverns i.e. holes in the rock. See: The Basics of Underground Natural Gas Storage http://www.eia.doe.gov/pub/oil_gas/natural_gas/analysis_publications/storagebasics/storagebasics.html

Natural gas may be stored in a number of different ways. It is most commonly held in inventory underground under pressure in three types of facilities. These are: (1) depleted reservoirs in oil and/or gas fields, (2) aquifers, and (3) salt cavern formations. Each storage type has its own physical characteristics (porosity, permeability, retention capability) and economics Most existing gas storage in the United States is in depleted natural gas or oil fields that are close to consumption centers. Depleted oil and gas reservoirs are the most commonly used underground storage sites because of their wide availability. In some areas, most notably the Midwestern United States, natural aquifers have been converted to gas storage reservoirs. An aquifer is suitable for gas storage if the water bearing sedimentary rock formation is overlaid with an impermeable cap rock Salt caverns provide very high withdrawal and injection rates relative to their working gas capacity. The large majority of salt cavern storage facilities have been developed in salt dome formations located in the Gulf Coast states. Salt caverns have also been leached from bedded salt formations in Northeastern, Midwestern, and Southwestern states.

The predominate physical factor is the porosity of a formation. In one underground storage field the porosity of the sedimentary rock was 18%--looked like a soft rock. But, in a cubic foot section of such a formation, as an example, 10 to 15 scf of gas may be stored at typical operating pressures. The permeability, closure of the structure, and impermeability of the capping formation are also important. Old abandoned wells, improperly plugged create problems. In one case that I experienced, old oilfield drilling equipment was dropped down the well bore, sealing it again the low depleted formation pressure. Some 13 months and several million dollars were spent in fishing for, and removing the junk, to allow a proper high pressure plug.

There are many more stories about over-pressuring a formation resulting in leaks, domestic water contamination, fires from water wells and in houses (1952-53, Herscher, IL). Failure to anticipate the the minimal CO2 in natural gas, in the presence of water, forms an acid, which over time corrodes the inner wall of a pipe, creating leaks and/or explosions.

Transport==Ocean pipelines do exist: See: "Natural Gas Pipeline Connections Between Algeria And Europe1 Transmed:The 670-mile, 2.32-Bcf/d Trans-Mediterranean (Transmed) line runs from Tunisia and Sicily, to mainland Italy. Completed in 1983 and doubled in 1994, there are plans to construct an additional compressor station along the Transmed that could increase capacity to 3.48-Bcf/d. MEG: An international consortium, led by Spain's Enagas, Morocco's SNPP, and Sonatrach, operates the 1,000-mile, 820-Mmcf/d Maghreb-Europe Gas, MEG, completed in 1996, connects Hassi R'mel with Cordoba, Spain via Morocco. In August 2001, Sonatrach awarded ABB a $93 million contract to build a natural gas compressor station on the MEG line in order to increase the line's capacity to 1.78 Bcf/d. Medgaz: In July 2001, a consortium led by Spain's Cepsa and Algeria's Sonatrach agreed to build a natural gas pipeline linking Algeria and Europe: Medgaz. The 120-mile Medgaz will link Algeria to Spain, with an eventual extension to France. In September 2002, the consortium completed a study of the line's feasibility, and initial construction on the project should begin around June 2007. The $1.2 billion Medgaz, which should be completed by 2009, will have an initial capacity of 390 Mmcf/d, increasing to a maximum of 1.55 Bcf/d. There are also plans to run a parallel power cable. In November 2002, Cepsa said that it had signed a letter of intent to purchase 35 Bcf/y of natural gas via Medgaz, and in 2004, Iberdrola also agreed to purchase 35 Bcf/y from the line. Galsi Pipeline In 2002, Sonatrach signed a deal with Italy's Enel and Germany's Wintershall to form Galsi, a consortium to build a natural gas pipeline from Algeria to Italy. The pipeline will run from Gassi R'Mel to El Kal, Algeria, then an underwater section to Cagliari, Sardinia. This is to be followed by an onshore section to Olbia, Sardinia, then a final, offshore pipeline to C.D. Pescaia, Italy. The Galsi pipeline, which is currently under construction, will have initial capacity of 770-990 Mmcf/d, and, as with Medgaz, there are plans for a parallel power cable. The Galsi project could be completed by late 2009. 1/ A synopsis of information from EIA, Energy Information Administration, found @http://www.eia.doe.gov/emeu/cabs/Algeria/NaturalGas.html"

OTHER COMMENTS Existing gas pipeline systems, including transmission compressor station platforms, in the Gulf of Mexico and the North Sea, as examples, demonstrate the feasibility of ocean pipelines. The frictional loss of pressure and thus throughput, dictate the need for periodic compressor stations along any long-distance pipeline. The feasibility of such platforms in the mid-Atlantic limits the current economic justification of such ocean pipelines, balancing cost with transmission capacity. International relations projections over the life of the project are also factors. For the future, subterranean electric compressor modules? Intercontinental super-conducting power cables tapped for the compressor modules? Electric power for the compressors from subterranean ocean current powered turbine-generators? Given the technological progress if the last 100 years, who can say it can’t be done. —Preceding unsigned comment added by Oldgaspipeliner (talk • contribs) 15:06, 26 March 2009 (UTC)

Marsh Gas

this should have its own page, where things like wil-0 the wisp and historic references would be, along with anything else to do with the gas from that source. IceDragon64 (talk) 14:27, 20 July 2009 (UTC)

Same to Town Gas erroneously listed as a source of natural gas. Clearly not.--BBird (talk) 17:01, 11 November 2009 (UTC)

Letdown station

Do we have an article on letdown stations where the high pressure gas goes to low pressure gas ? Mion (talk) 09:36, 5 November 2009 (UTC)