what is natural gas?
Natural gas is a gaseous fossil fuel consisting primarily of methane but including significant quantities of ethane, propane, butane, and pentane—heavier hydrocarbons removed prior to use as a consumer fuel —as well as carbon dioxide, nitrogen, helium and hydrogen sulfide. Fossil natural gas is found in oil fields (associated) either dissolved or isolated in natural gas fields (non-associated), and in coal beds (as coalbed methane).
Natural gas is often informally referred to as simply gas, especially when compared to other energy sources such as electricity. Before natural gas can be used as a fuel, it must undergo extensive processing to remove almost all materials other than methane. The by-products of that processing include ethane, propane, butanes, pentanes and higher molecular weight hydrocarbons, elemental sulfur, and sometimes helium and nitrogen. –http://en.wikipedia.org/wiki/Natural_gas
Recently, individuals and companies with a financial stake in natural gas production have been engaged in an effort to re-brand natural gas as an ‘alternative’ fuel. Since in English the word ‘alternative’ describes any option that isn’t the standard or default, and natural gas is not the standard fuel for, say, cars and trucks, no one can write them a ticket for their highly elastic use of the word and concept. However, by the definition of the term as it has been used for decades, natural gas is not an alternative fuel. “Alternative fuels, also known as non-conventional fuels, are any materials or substances that can be used as a fuel, other than conventional fuels. Conventional fuels include: fossil fuels (petroleum (oil), coal, propane, and natural gas), and nuclear materials such as uranium. Some well known alternative fuels include biodiesel, bioalcohol (methanol, ethanol, butanol), chemically stored electricity (batteries and fuel cells), hydrogen, non-fossil methane, non-fossil natural gas, vegetable oil and other biomass sources.” – http://en.wikipedia.org/wiki/Alternative_fuel
In fact, natural gas is just another highly polluting hydrocarbon and conventional – that is, non-alternative – fuel like oil, to which it is closely related and with which it is frequently found. Further, extracting natural gas and transporting it to markets takes huge amounts of, you guessed it, (imported) oil.
what’s hydraulic fracturing?
Hydraulic fracturing, as used for natural gas extraction, is the process by which water, frequently mixed with proppants and chemicals, is forced down a well bore at extremely high pressure in order to create or expand fractures to release gas from the rock formation in which it is trapped. Proppants are small particles such as sand or synthetic beads, that hold open the newly-created fractures so that released gas can flow towards the well. The process is also known as fracking, hydrofracking, or any of several other variants.
With the creation or restoration of fractures, the surface area of the formation exposed to the borehole is increased and the fracture provides a conductive path connecting the now-freed gas to the well. Thus, hydraulic fracturing effectively increases the rate that fluids can be produced from the reservoir formations.
This process has made it economically viable to extract natural gas from formations in which the gas is trapped so tightly in very small bubbles or pores that very little would naturally flow to the well. “In order to retrieve gas at a commercially profitable rate, most tight-gas reservoirs need to be fractured.”
The main industrial use of hydraulic fracturing, and the purpose for which the technique was developed, is in stimulating production from oil and gas wells. Hydraulic fracturing is also applied to stimulating groundwater wells, preconditioning rock for caving or inducing rock to cave in mining, as a means of enhancing waste remediation processes (usually hydrocarbon waste or spills), to dispose of waste by injection into suitable deep rock formations, and as a method to measure the stress in the earth.
Various forms of hydraulic fracturing have been developed for differing circumstances. The one now causing intense concern here in New York is known as ‘high-volume hydraulic fracturing’ (HVHF), and ‘slick water fracturing.’ In this method, millions of gallons of initially clean water per well are intentionally contaminated with the addition of a wide range and large volume of very toxic chemical additives. This technique combines “water with a friction-reducing chemical additive which allows the water to be pumped faster into the formation. Water fracs don’t use any polymers to thicken and the amount of proppant used is significantly less than that of gels. Slick water fracs work very well in low-permeability reservoirs, and they have been the primary instrument that has opened up unconventional plays like the Texas Barnett Shale. In addition to the cost advantage, water fracs require less cleanup and provide longer fractures…In order to effectively select the right combination and concentrations of frac fluid and propping agents, geologists must know a lot about a reservoir. To create the right approach to a frac job, geologists gather information from well logs about a variety of factors such as porosity, permeability, saturation levels, pressure and temperature gradients. Using this information, geologists run scenarios through 2D or 3D reservoir models to predict the outcomes of various approaches.” – http://www.enermaxinc.com/hydraulic-fracturing/
Despite these precautions, the process doesn’t always go according to intention. Regarding a subsurface trespass case before the Supreme Court of Texas, the Fort Worth Business Press reported the following: “The problem is, however, that fracture stimulation isn’t a precise science…in some ways, cracking the shale [predictably] could be thought of as trying to hammer a dinner plate into equal pieces…’You may plan a fracture that will go 1,000 feet and it might go 2,000 feet or 400 feet, ‘ said John S. Lowe, a professor of energy law at Southern Methodist University’s Dedman School of Law.”…’How do you prove any fracing was correct or incorrect in an area that is not precise to begin with?’ asked [John] Holden [a partner at Dallas-based Jackson Walker LLP]…’Either side has to prove what’s going on down below, and that’s hard for both sides.’…Lowe said, ‘You can bring the scientific evidence, the scientific testing to see whether or not a trespass has occurred but I’m not sure you can rely on it 100 percent.’” Fort Worth Business Press, July 7, 2008
This uncertainty about how exactly to plan and carry out a fracturing job according to the often obscure details about the site geology as well as that of the surrounding area is one reason to be skeptical about the appropriateness of the technique. Not only do underground formations respectively contain or separate ‘good’ and ‘bad’ groundwater, they also obviously harbor many naturally-occurring toxic substances, such as those routinely found in association with oil and gas. In the US alone, there are thousands of instances of groundwater contamination from hydraulic fracturing operations over a wide range of geological and reservoir conditions; to most of us, common sense suggests that any technology that could exploit existing weaknesses in formations or is known or theorized to have unpredictable results, with demonstrable adverse consequences, should be examined with a high degree of scientific skepticism.
what about alternatives to water usage, such as fracturing with propane?
“A few “eco-friendly” fracturing schemes are out and about, but they all come with some issues.
“Propane is a gas at ordinary pressures, but can be fairly easily liquefied with pressure. It is, of course, a fossil fuel itself. Using propane would get around using millions of gallons of water, but would not deal with some real technological challenges. First, in order to suspend sand or other proppants, liquid propane needs to be thickened, typically by foaming agents like peroxide. Using peroxide requires the addition of even more corrosion inhibitors than when water is used, and biocides are still required to control microbe growth. (I’ve heard misinformation that fracking with propane requires no chemical additives; that’s just not true.)
“The use of propane introduces new problems with controlling a pressurized liquid that quickly turns to a gas when the pressure is released. It’s not easy or cheap, and a lot of gas escapes into the atmosphere. This is a greenhouse gas, though not as potent as carbon dioxide (another [so-called] “green” fracking fluid candidate) or methane.
“And none of these exotic “fluids under pressure” help with the toxicity of the deep brines that still flow out of gas well bores. These brines continue to be among the greatest waste problems faced by the industry.” – Ron Bishop
- The only benefit of fracturing with propane and other gases would be the apparent elimination of water usage for the hydraulic fracturing phase of well development.
- Water would still be required for parts of the drilling phase.
- Frequently, one of the key problems caused by gas extraction, groundwater contamination, takes place during the drilling phase, prior to fracking. There are multiple opportunities for groundwater contamination to occur during the drilling phase, starting with the very first stage, which necessarily takes place with no casing in place yet, as lengths of casing can only be inserted after sections of the borehole are drilled out.
- Regardless of the method used to complete (or ‘frack’) a well, the overall footprint of industrial impacts on the landscape, and on future options for land use, remain the same: the same number of pipeyards/chemical storage sites, access roads, well pads, compressor stations, pipelines, and gas processing units.
So merely reducing the amount of water hauled to the site for fracturing would leave in place most of the major problems associated with petro-methane extraction.
how about horizontal drilling?
Horizontal drilling, or directional drilling, is promoted as a way to avoid intensive surface disturbance such as that which was common in earlier hydrocarbon booms. (See picture at left.) While this is a desirable goal, horizontal drilling is not without its own impacts. These impacts are compounded dramatically when horizontal drilling is combined with hydraulic fracturing.
First, multiple wells drilled from a common pad, as is expected with horizontal drilling, require a much larger drill pad, as acknowledged in the draft scope of the DEC’s Supplemental Generic Environmental Impact Statement (dsSGEIS), section 2.1.4. Larger drill pads disturb more contiguous surface area and result in more surface runoff from one location. Second, it is horizontal drilling in tight shale that at least in part creates the distinction between conventional hydraulic fracturing and high-volume hydraulic fracturing (HVHF) because of the vastly greater quantities of water used to drill and fracture the vastly greater length of very resistant rock.
Though proponents claim that horizontal drilling will reduce the number of wells that must be drilled to access a given area in the target formation, in fact, New York State regulations continue to allow for wells to be spaced only 40 acres apart, which translates to 16 wells per square mile.
Horizontal drilling also makes it possible for drillers to remove gas from the property of a landowner who does not want to sell her or his gas reserves, even though the landowner denies the drillers access to the surface of his property. This is done through a DEC-mediated form of eminent domain called “compulsory integration.” (See below.)