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The What, Where and How of Shale Gas

RATIONAL MIDDLE ENERGY SERIES VISUAL CAPITALIST The What, Where and How of Shale Gas PART 1 NATURAL GAS has the potential to bridge the gap between the current oil-dominated energy mix and sustainable renewables. It's cheap, abundant, and the cleanest fossil fuel in the world. In fact, at today's consumption rates, estimated U.S. natural gas resources could be used to supply domestic electricity generation Recoverable resource: 482 trillion cu. ft oJ2 yealS Consumption: 25.18 billion cu. ft per day for electricity 1 barrel of oil = 464 lbs bitumous coal = 5,800 ft³ of natural gas CO2 Emissions (Ibs) 200 400 600 800 1000 1400 Shale gas is trapped deep underground. How do we extract it and what does the process look like? About an acre of land Between 890-1340 truckloads are required over the life of a typical well. is cleared. TOP SOIL AQUIFER Each drill hole is typically a series of three casings made from layers of concrete and steel. -1000ft O SURFACE CASING Protects aquifers, soil and groundwater near the surface of the well. -2000ft The top of a well has the protection of all three sets of casings as it is the area most at risk of contamination by leaking hydrocarbons or salt water. -3000ft Underground aquifers are vital: 95% of rural US and 35% of cities depend on aquifers for fresh water 2 INTERMEDIATE CASING -4000ft Further protects the well against subsurface hazards including pressure zones or salt-water deposits. 3 PRODUCTION CASING -1 MILE Runs along the length of the entire well. In shale gas wells, this casing also runs laterally along the shale resource (horizontal drilling) to maximize production. -6000ft What is Shale? Shale is incredibly dense sedimentary rock with hydrocarbons trapped inside. Shale has low permeability and gas does not flow through it easily. -7000ft SHALE FORMATION -8000ft What is Fracking? Hydraulic fracturing (fracking) is the process of creating microfractures in shale resources to free hydrocarbons. Combined with horizontal drilling technology, fracking allows companies to economically extract shale gas. Once the drilling is complete, a perforation gun is low- ered to the bottom of the well and blasts holes through the production casing. Hydraulic fracturing fluid is pumped down the well and into the resource via the holes made by the perforation guns. This creates microfractures in the shale. Sisl52f2826 Pressure Proppant holds the fractures open while natural gas flows into the well, then up to the surface. Hydraulic Fracturing Fluid The exact breakdown of fracturing fluid can vary from well to well and depends on local geology and the specific rock properties. 9% 90% 1% Proppant Water Chemicals 5 Million Gallons The exact amount and makeup of chemicals used in hydraulic fracking fluid can differ from well to well, though are often harmful. In fact: Proppant is made of sand and other silica or ceramic pieces. Once the fracking fluid recedes, it remains behind and props open fractures which allows gas to flow into the well and up to the surface. 87% Skin irritants 68% Respiratory irritants 72% Harmful if swallowed 9% Carcinogens (incl. suspected) How Much Water Does A Shale Gas Well Use? Here's an Olympic sized swimming pool 82 ft x 164 ft x 6 ft 7in - 660,000 gallons Shale Gas Well Annual Golf Course Irrigation 5 million gallons (Over the lifespan of the well) 114 million gallons Estimated number of active shale gas wells in America: Estimated number of golf courses in America: 40,000 20,000 VATION Hydraulic fracturing fluid and wastewater have contaminated aquifers and groundwater in the past. The United States Environmental Protection Agency has confirmed that all instances were a result of: A Casing failures Blowouts Surface spills There is concern that this fluid will work its way upward from the shale and contaminate drinking water. Fortunately, the water is not only trapped in relatively impermeable shale but also separated by thousands of feet of rock - this provides the necessary buffer to stop this from happening. | 1454 ft In fact, hydraulic fracturing fluid actually poses a greater threat to groundwater when it returns to the surface as wastewater. Fracking Waste Water In addition to chemicals, fracking wastewater can contain formation water. Formation water is salty water that was already present in the shale before fracking, and it can contain harmful levels of: 10-30% of fracking water comes back up the well as "flowback fluid" On average, this is enough water to fill an Olympic- sized swimming pool. Heavy metals Naturally occurring radioactive materials Volatile organic compounds The rest of the water remains in the cracks created by fracking and is thousands of feet below the surface. Total dissolved solids If this wastewater is spilled or improperly stored at the surface, it can leak out and contaminate drinking water aquifers from above. Disposal Options 3. Injection Wells Storage / Reuse Treatment Closed Tank Open Pit The waste water remains in storage until it can be used in subsequent fracking projects. If practical, existing water processing plants can be up- graded to handle and remove the harmful components of fracking wastewater. A well is drilled and cased in a very similar way to the actual natural gas well - but this time the target is a porous layer of earth beneath impermeable beds that confines the wastewater far beneath the surface. There are two primary waste water storage methods: Open pit, and closed tank. The latter is preferred as leaks are much easier to spot and fix. Pro Creates value from an otherwise waste material. Pro Injection wells are the only dis- posal option that fully prevents groundwater contamínation. Pro Less freshwater is required for future fracks and less strain is put on local water supplies. Con Existing water processing plants often need to be upgraded before they are capable of dealing with the harmful chemicals found in waste water. Con Using higher amounts of water and pressure, these wells can create small earthquakes in certain geological formations. Part of the responsibility of cre- ating a proper injection is choos- ing a location that will not cause seismic activity. Con Presents opportunity for surface spills and leaks. This varies depending on the type of storage used. METHANE The point at which gas extraction creates greenhouse gases equal to coal. The major component of natural gas. It is 25x more potent than carbon dioxide as a greenhouse gas. % of leakage in U.S. Natural G Small amounts of methane leak into the atmosphere throughout the natural gas consumption cycle. Natural gas power plants are only 'cleaner' than coal power plants as long as total methane leakage is below 3.2% of the source well's production levels. The EPA is 95% confident total leakage falls within this range EPA Estimate of total U.S. natural gas production leakage More work needs to be done to determine actual leakage amounts with certainty, as too much leakage could mean natural gas is not as clean as currently touted. Methane CH4 There are risks involved with extracting natural gas. The good news is that these risks are all well understood and manageable. The necessary technology needed to safely drill and frack already exists. With proper regulation and risk management, natural gas drilling and fracking will be a worthwhile step towards a renewable energy future. NOW THAT YOU'VE READ THIS OVERVIEW ON SHALE GAS, LET'S TALK ABOUT IT. Don't miss the Rational Middle video series. 0:00 / 5:03 Visual Capitalist is committed to providing independent and non-biased content for educational purposes. Visual Capitalist received no direct funding from third-party companies or organizations to produce this infographic. VISUAL CAPITALIST Educating a new generation of investors on resource investing and managment VISUAL CAPITALIST IIIIII. In association with

The What, Where and How of Shale Gas

shared by visualcap on Aug 23
Natural gas has the potential to bridge the gap between the current oil dominated energy mix and sustainable renewables. It’s cheap, abundant, and the cleanest fossil fuel in the world. In fact, at ...


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