Natural Gas Technology
Over the past thirty years, the oil and natural gas industry has transformed into one of the most technologically advanced industries in the United States. New innovations have reshaped the industry into a technology leader, in all segments of the industry. This section will discuss the role of technology in the evolution of the natural gas industry, focusing on technologies in the exploration and production sector, as well as a few select innovations that have had a profound effect on the potential for natural gas.
In recent years, the demand for natural gas has grown substantially. However, as the natural gas industry in the United States becomes more mature, domestically available resources become harder to find and produce. As large, conventional natural gas deposits are extracted, the natural gas left in the ground is commonly found in less conventional deposits, which are harder to discover and produce than has historically been the case. However, the natural gas industry has been able to keep pace with demand and produce greater amounts of natural gas despite the increasingly unconventional and elusive nature. The ability of the industry to increase production in this manner has been a direct result of technological innovations. Below is a brief list of some of the major technological advancements that have been made recently:
Advances in the Exploration and Production Sector
Technological innovation in the exploration and production sector has equipped the industry with the equipment and practices necessary to continually increase the production of natural gas to meet rising demand. These technologies serve to make the exploration and production of natural gas more efficient, safe, and environmentally friendly. Despite the fact that natural gas deposits are continually being found deeper in the ground, in remote, inhospitable areas that provide a challenging environment in which to produce natural gas, the exploration and production industry has not only kept up its production pace but in fact, has improved the general nature of its operations. Some highlights of technological development in the exploration and production sector include:
- 22,000 fewer wells are needed on an annual basis to develop the same amount of oil and gas reserves as were developed in 1985.
- Had technology remained constant since 1985, it would take two wells to produce the same amount of oil and natural gas as one 1985 well. However, advances in technology mean that one well today can produce two times as much as a single 1985 well.
- Drilling wastes have decreased by as much as 148 million barrels due to increased well productivity and fewer wells.
- The drilling footprint of well pads has decreased by as much as 70 percent due to advanced drilling technology, which is extremely useful for drilling in sensitive areas.
- By using modular drilling rigs and slim hole drilling, the size and weight of drilling rigs can be reduced by up to 75 percent over traditional drilling rigs, reducing their surface impact.
- Had technology, and thus drilling footprints, remained at 1985 levels, today’s drilling footprints would take up an additional 17,000 acres of land.
- New exploration techniques and vibrational sources mean less reliance on explosives, reducing the impact of exploration on the environment.
Some of the major recent technological innovations in the exploration and production sector include:
3-D and 4-D Seismic Imaging – The development of seismic imaging in three dimensions greatly changed the nature of natural gas exploration. This technology uses traditional seismic imaging techniques, combined with powerful computers and processors, to create a three-dimensional model of the subsurface layers. 4-D seismology expands on this, by adding time as a dimension, allowing exploration teams to observe how subsurface characteristics change over time. Exploration teams can now identify natural gas prospects more easily, place wells more effectively, reduce the number of dry holes drilled, reduce drilling costs, and cut exploration time. This leads to both economic and environmental benefits.
- CO2-Sand Fracturing – Fracturing techniques have been used since the 1970s to help increase the flow rate of natural gas and oil from underground formations. CO2-Sand fracturing involves using a mixture of sand proppants and liquid CO2 to fracture formations, creating and enlarging cracks through which oil and natural gas may flow more freely. The CO2 then vaporizes, leaving only sand in the formation, holding the newly enlarged cracks open. Because there are no other substances used in this type of fracturing, there are no ‘leftovers’ from the fracturing process that must be removed. This means that, while this type of fracturing effectively opens the formation and allows for increased recovery of oil and natural gas, it does not damage the deposit, generates no below ground wastes, and protects groundwater resources.
- Coiled Tubing – Coiled tubing technologies replace the traditional rigid, jointed drill pipe with a long, flexible coiled pipe string. This greatly reduces the cost of drilling, as well as providing a smaller drilling footprint, requiring less drilling mud, faster rig set up, and reducing the time normally needed to make drill pipe connections. Coiled tubing can also be used in combination with slim hole drilling to provide very economical drilling conditions and less impact on the environment.
- Measurement While Drilling – Measurement-While-Drilling (MWD) systems allow for the collection of data from the bottom of a well as it is being drilled. This allows engineers and drilling teams access to up to the second information on the exact nature of the rock formations being encountered by the drill bit. This improves drilling efficiency and accuracy in the drilling process, allows better formation evaluation as the drill bit encounters the underground formation, and reduces the chance of formation damage and blowouts.
- Slim Hole Drilling – Slimhole drilling is exactly as it sounds; drilling a slimmer hole in the ground to get to natural gas and oil deposits. In order to be considered slim hole drilling, at least 90 percent of a well must be drilled with a drill bit less than six inches in diameter (whereas conventional wells typically use drill bits as large as 12.25 inches in diameter). Slim hole drilling can significantly improve the efficiency of drilling operations, as well as decrease its environmental impact. In fact, shorter drilling times and smaller drilling crews can translate into a 50 percent reduction in drilling costs, while reducing the drilling footprint by as much as 75 percent. Because of its low-cost profile and reduced environmental impact, slim hole drilling provides a method of economically drilling exploratory wells in new areas, drilling deeper wells in existing fields, and providing an efficient means for extracting more natural gas and oil from undepleted fields.
- Offshore Drilling Technology – The offshore oil and gas production sector is sometimes referred to as ‘NASA of the Sea’, due to the monumental achievements in deepwater drilling that have been facilitated by state of the art technology. Natural gas and oil deposits are being found at locations that are deeper and deeper underwater. Whereas offshore drilling operations used to be some of the riskiest and dangerous undertakings, new technology, including improved offshore drilling rigs, dynamic positioning devices, and sophisticated navigation systems are allowing safe, efficient offshore drilling in waters more than 10,000 feet deep.
The above technological advancements provide only a snapshot of the increasingly sophisticated technology being developed and put into practice in the exploration and production of natural gas and oil. New technologies and applications are being developed constantly, and serve to improve the economics of producing natural gas, allow for the production of deposits formerly considered too unconventional or uneconomic to develop, and ensure that the supply of natural gas keeps up with steadily increasing demand. Sufficient domestic natural gas resources exist to help fuel the U.S. for a significant period of time, and technology is playing a huge role in providing low-cost, environmentally sound methods of extracting these resources.
Two other technologies that are revolutionizing the natural gas industry include the increased use of liquefied natural gas, and natural gas fuel cells. These technologies are discussed below.
Liquefied Natural Gas
Cooling natural gas to about -260°F at normal pressure results in the condensation of the gas into liquid form, known as Liquefied Natural Gas (LNG). LNG can be very useful, particularly for the transportation of natural gas, since LNG takes up about one six hundredths the volume of gaseous natural gas. While LNG is reasonably costly to produce, advances in technology are reducing the costs associated with the liquefaction and regasification of LNG. Because it is easy to transport, LNG can serve to make economical those stranded natural gas deposits for which the construction of pipelines is uneconomical.
LNG, when vaporized to gaseous form, will only burn in concentrations of between 5 and 15 percent mixed with air. In addition, LNG, or any vapor associated with LNG, will not explode in an unconfined environment. Thus, in the unlikely event of an LNG spill, natural gas has little chance of igniting an explosion. Liquification also has the advantage of removing oxygen, carbon dioxide, sulfur, and water from the natural gas, resulting in LNG that is almost pure methane.
LNG is typically transported by specialized tanker with insulated walls and is kept in liquid form by autorefrigeration, a process in which the LNG is kept at its boiling point so that any heat additions are countered by the energy lost from LNG vapor that is vented out of storage and used to power the vessel.
The increased use of LNG is allowing for the production and marketing of natural gas deposits that were previously economically unrecoverable. Although it currently accounts for only about 1 percent of natural gas used in the United States, it is expected that LNG imports will provide a steady, dependable source of natural gas for U.S. consumption.
Natural Gas Fuel Cells
Fuel cells powered by natural gas are an extremely exciting and promising new technology for the clean and efficient generation of electricity. Fuel cells have the ability to generate electricity using electrochemical reactions as opposed to the combustion of fossil fuels to generate electricity. Essentially, a fuel cell works by passing streams of fuel (usually hydrogen) and oxidants over electrodes that are separated by an electrolyte. This produces a chemical reaction that generates electricity without requiring the combustion of fuel, or the addition of heat as is common in the traditional generation of electricity. When pure hydrogen is used as fuel, and pure oxygen is used as the oxidant, the reaction that takes place within a fuel cell produces only water, heat, and electricity. In practice, fuel cells result in very low emission of harmful pollutants, and the generation of high-quality, reliable electricity. The use of natural gas-powered fuel cells has a number of benefits, including:
Clean Electricity – Fuel cells provide the cleanest method of producing electricity from fossil fuels. While pure hydrogen, pure oxygen fuel cell produces only water, electricity, and heat, fuel cells in practice emit only trace amounts of sulfur compounds and very low levels of carbon dioxide. However, the carbon dioxide produced by fuel cell use is concentrated and can be readily recaptured, as opposed to being emitted into the atmosphere.
- Distributed Generation – Fuel cells can come in extremely compact sizes, allowing for their placement wherever electricity is needed. This includes residential, commercial, industrial, and even transportation settings.
- Dependability – Fuel cells are completely enclosed units, with no moving parts or complicated machinery. This translates into a dependable source of electricity, capable of operating for thousands of hours. In addition, they are very quiet and safe sources of electricity. Fuel cells also do not have electricity surges, meaning they can be used where a constant, dependable source of electricity is needed.
- Efficiency – Fuel cells convert the energy stored within fossil fuels into electricity much more efficiently than the traditional generation of electricity using combustion. This means that less fuel is required to produce the same amount of electricity. The National Energy Technology Laboratory estimates that used in combination with natural gas turbines, fuel cell generation facilities can be produced that will operate in the 1 to 20 Megawatt range at 70 percent efficiency, which is much higher than the efficiencies that can be reached by traditional generation methods within that output range.
The generation of electricity has traditionally been a very polluting, inefficient process. However, with new fuel cell technology, the future of electricity generation is expected to change dramatically in the next ten to twenty years. Research and development into fuel cell technology are ongoing, to ensure that the technology is refined to a level where it is cost-effective for all varieties of electric generation requirements.
Natural Gas Technology Resources
The natural gas industry is joined by government agencies and laboratories, private research and development firms, and environmental technology groups in coming up with new technologies that may improve the efficiency, cost-effectiveness, and environmental soundness of the natural gas industry. Below are links to a number of resources that provide information on new technological developments in the oil and natural gas industry:
- The Department of Energy’s Office of Fossil Energy R&D Program
- The National Energy Technology Laboratory
- The Natural Gas & Oil Technology Partnership
- The Oil and Gas Journal