Natural Gas Properties Natural gas in its native state is colorless and odorless. Mercaptan is the harmless, non-toxic chemical that is added to natural gas to make it easier to detect in case of a leak. The most important thing to know about mercaptan is that it stinks. Some people compare it to the smell of rotten eggs. In a concentrated form, the smell is almost unbearable. It takes only a few parts per million of mercaptan to give natural gas a smell. That is precisely why we add it to natural gas. If we did not add mercaptan, it would be hard for you to know that unlit natural gas was coming from your stove after you left the valve turned on. Leaks from furnaces and hot water heaters would be nearly impossible to detect without expensive equipment. Mercaptans contain sulfur. That's what makes them smell. It blends well with natural gas and, in a gaseous state, has much the same properties as natural gas, so it will also rise and dissipate with natural gas.
Formed by same basic processes as oil. Can be found alone in reservoirs (non- associated gas) or in the same reservoirs as crude oil (associated gas). Also can be found in coal beds. (more later) Much of what we know about finding reserves we learned from searching for oil. Natural Gas Properties
Discovery Some scholars speculate that people living in the Middle East discovered natural gas between 6000 and 2000 BC when lightning strikes ignited natural gas seeping from the ground. The Chinese burned natural gas as early as 211 BC to dry rock salt found in limestone rock. They also drilled the first known natural gas wells, using bamboo poles and primitive bits, but they were only able to reach depths of 500 feet. Bio-gas Natural gas is not the only source of methane. Methane can also be obtained by fermenting organic matter, such as manure, in low levels of oxygen. In such conditions, bacteria will use the nutrients in manure as a food source and will release methane and carbon dioxide as waste products. This methane, known as bio-gas, can be collected and used as a fuel source.
The first well was drilled in 1821. Before the industry could expand, we had to build a pipeline system to deliver the gas to customers. Natural Gas After WWII, a high pressure pipeline network was constructed to serve the entire US. (over 1,000,000 miles of pipe.)
U.S. Natural Gas Pipeline Network More than 210 natural gas pipeline systems. 300,000 miles of interstate and intrastate transmission pipelines More than 1,400 compressor stations that maintain pressure on the natural gas pipeline network and assure continuous forward movement of supplies More than 11,000 delivery points, 5,000 receipt points, and 1,400 interconnection points that provide for the transfer of natural gas throughout the United States. 29 hubs or market centers that provide additional interconnections 394 underground natural gas storage facilities 55 locations where natural gas can be imported/exported via pipeline 5 LNG (liquefied natural gas) import facilities and 100 LNG peaking facilities.
Units Gases are usually measured in volume units. In the US, this would be in cubic feet. Gas companies like to measure in units of 1 therm = 100 cubic feet 1 therm = 100 000 BTU 1.14 therm = energy content of gallon of gasoline
Exploration Much of what we know comes from searching for oil. Possible Deep earth mechanism for production. Could signify a large (but deep) supply. Potential to generate methane from biological processes.
Costs of Crude Oil and Natural Gas Wells Drilled
CBM accounts for 10% of all domestic natural gas reserves and, In 2004, CBM accounted for nine percent of U.S. dry gas production. The Powder River Basin in northeast Wyoming has become a major supplier of coal bed methane. Since 2001, CBM production in the Basin has increased 200 percent to 332 billion cubic feet and now comprises almost 20 percent of U.S. annual CBM production. Coalbed Methane Proved Reserves and Production (Billion Cubic Feet)
Environmental Problems with CBM Discharge water at up to 100 gallon per minute per well. (15,000-20,000 wells) Discharge water is more “salty” than normal and can cause significant soil damage. New roads and power lines to get to the wells Large loud compressors.