Understanding the Basics of Gas Exploration and Production And some of the career opportunities created by the industry Eric K. Albert, PhD Our economy runs on energy! In 2009: Energy Information Administration Natural Gas A non-renewable energy resource Used in a variety of ways: Energy Information Administration, 2005 As an energy source: Natural gas burns more cleanly than other fossil fuels BUT Still results in CO2 emissions! And unburned natural gas (methane) is considered a greenhouse gas… 2008 US Natural Gas Total Production 21,200 Billion Cubic Feet (BCF) Consumption 23,200 BCF Imports 3,984 BCF Exports 1,006 BCF Wellhead price $7.96 / thousand cubic feet Avg. City Gate price $9.18 / thousand cubic feet Top US Gas Producing State 7,760 BCF: Texas Energy Information Administration How much energy? A BTU is the heat required to raise the temperature of one pound of water 1 degree Fahrenheit One cubic foot of natural gas (volume) contains about 1031 BTU One candy bar has about 1000 BTU! One cubic foot of gasoline contains about 961,000 BTU! [about 7.6 gallons] Equivalent Energy Cost January 2011* Natural Gas price is $4.48 / Million BTU (MMBTU) compared to today’s price of $3.19/gallon of gasoline the equivalent energy price of 1 gallon of gasoline is $25.23 MMBTU Put another way, at current prices, the same energy from Natural Gas is about 1/6 the cost! *NYMEX How is Natural Gas formed? Trapped organic matter decomposing under pressure and heat… In time, depending on conditions, we get: Coal beds Oil fields Natural gas Think: even landfills are recovering methane from decomposing trash How is it found? Geologists use a variety of means to locate possible sources… Knowing where it has been found already Historical geological setting Specific site location typically uses Seismic methods Historical Oil and Gas Production Oil: green Gas: red Oil & Gas: yellow USGS Main Phases of Gas Development Exploration Land identification for sites Location of deposits Environmental concerns Proving potential reserves Drilling Land leasing, right of ways Permits Pad development Roads and water infrastructure Production Pipeline construction Monitoring and compliance Pumping and storage Well maintenance Post-production Capping / sealing wells Water quality monitoring Other compliance issues Site reclamation EXPLORATION Seismic Survey An array of geophones Data collection equipment A “noise” source – Vibrating trucks Explosives The reflected sound waves are collected and analyzed with computers to form structural images Seismic Surveys Resolution Resources Marcellus Shale Gas deposit known since the 1930’s Technology for recovery not available Price of gas too low for cost of drilling 6,000’ -7,000’ underground, maybe more PA gas wells: 35,000+ already in place Estimates 4,000 per year may be added Traps Pore spaces filled Pore spaces don’t communicate Both of these types of rocks are impermeable, meaning that they do not allow liquids or gasses to move through them! Geology.com Drilling DTE Energy Horizontal drilling is employed to connect to the largest reservoir space The drill string does not turn…but is steered to a horizontal line… This is accomplished through a steerable drill (Mud Motor) and a follow-behind probe (Measure While Drilling) What does a borehole look like? Side View Top View Note: the casing system seals off higher elevations of rocks in the well so that only the production area is eventually connected. Well Logging Gamma Ray Neutron After the well is drilled, a log is made… Gamma ray = natural radiation in the rocks Neutron = higher reading means more hydrogen* This along with other data collected in the log helps to indentify if this will be a productive hole… *Natural gas is a hydrocarbon! Final Steps After the production area is reached: The casing is sealed to this area The production area casing is perforated by blasting The rocks surrounding the production area are fractured (hydraulic fracturing) PRODUCTION Deal or No Deal? Even so, after all this, the well might not be productive! Non-productive wells are plugged with cement and operations cease. Hydraulic Fracturing might be repeated in one well several times to attempt to increase pressure and recovery Higher pressure = higher flow rate = more valuable well Transport A producing well is then connected to a pipeline for transport Also, to buffer the effects of seasonal demand, underground gas storage reservoirs are used. In PA there are at least 88 active reservoirs Well Maintenance Well production is monitored both remotely and by on-site inspections Routine maintenance of the site is necessary to confirm safety and integrity of the well Water quality monitoring of nearby drinking water sources, as well as natural sites may be needed (looking for leakage of gas into sources…) POSTPRODUCTION Well Life A well might produce for 5, 10, even 20 years Production rates decline with time… Eventually the rate may be deemed too low to be useful, or non-economic Wells are disconnected, sealed (capped) with cement, and a surface vent pipe is installed. Where are the jobs? Exploration Land identification for sites Surveyors, Civil engineers, etc. Location of deposits Geologists Environmental concerns Environmental techs, biologists, forest technology, chemists Proving potential reserves Geologists, Drilling Petroleum & NG Engineers Drilling Land leasing, right of ways Paralegals, title search, lawyers, land agents Permits Hydrologists, civil engineers, land planners Pad development Commercial drivers, riggers, drill operators, diesel power generation, construction, welding, electrical, heavy equipment Roads and water infrastructure Similar to “Pad development” Production Pipeline construction Heavy equipment operators, diesel techs, welders, riggers, surveyors Monitoring and compliance Electronics, computer networking, communications / satellite techs, biologists, hydrologists, chemists Pumping and storage Well maintenance Post-production Capping / sealing wells Construction, welders, general maintenance Water quality monitoring Other compliance issues Site reclamation Heavy equipment operators, forest / reclamation technology How it all got started… Drake Well Museum Sam Kier, 1840’s… Questions?