Planet Earth Course (GEOL 110) - Chapter 4: Earth's Natural Resources PDF

Planet Earth Course (GEOL 110)- BLT form Chapter 4: Earth’s Natural Resources Delivery method: face-to-face Dr. Dalal Alshamsi Geology Department, College of Science United Arab Emirates University Session 1 Resources Known or hypothetical concentrations that can now or in the fut...

Planet Earth Course (GEOL 110)- BLT form Chapter 4: Earth’s Natural Resources Delivery method: face-to-face Dr. Dalal Alshamsi Geology Department, College of Science United Arab Emirates University Session 1 Resources Known or hypothetical concentrations that can now or in the future be developed as energy sources. Reserves Estimated quantities that engineering or geological analysis demonstrate to be producible under current economic operating conditions Energy sources for electricity generation in the world in 2018 Source: Statistical Review of World Energy 2019; https://www.renewable-ei.org/en/statistics/international/ Trends in Electricity Generation 1985-2018 Source: Statistical Review of World Energy 2019 Non-renewable Energy Sources Fossil fuels: Oil, gas and coal Oil, gas and coal are fossil fuels! Oil, gas and coal are called fossil fuels because they formed from once living organisms. Fossil fuels are also called hydrocarbons because they are composed mainly of hydrogen and carbon. Most of oil and gas are formed from micro-organisms, however, coal is formed mainly from plants. The floating micro-organisms are called plankton. They can be either plants (phyto-planktons) or animals (zoo-planktons). http://geologylearn.blogspot.com/ How did fossil fuels form? 1. Accumulation of sufficient These processes take place in the quantity of organic matter. (Source Rock). Organic matter-bearing rock where 2. Rapid burial of organic formation of gas and oil takes place matter in poor oxygen is known as source rock. environment like mud The source rock is mainly which keeps the organic composed of mud. This mud lithify to form organic shale (oil shale). matter preserved. You can read more: 3. Compaction https://opentextbc.ca/geology/chapter/20-3-fossil-fuels/ 4. Temperature and pressure. Source rock Oil Shales Organic matter before transformation to petroleum (oil and gas) As the source rock buried, the organic matter transforms to solid, black, complex material which is called Kerogen. As temperature and depth increases the kerogen is transformed to oil and gas. The process of oil generation from Kerogen kerogen is called maturation of organic matter. 1- Oil and gas (petroleum) source rock The change of organic matter in source rock with respect to temperature and depth: Temperature Depth Production maturation (C) (km) 0-50 260 >6 Dead carbon Over mature (graphite)  Comparison between oil and gas Gas Oil Gas molecules are Oil molecules are much much smaller than bigger and more complex than gas molecules. oil molecules. Oil molecules are in two Gas is found only in forms: chain forms. A I. A chain includes 15 to 60 carbon atoms. chain includes 1 to II. Rings of carbon atoms. 4 carbon atoms. What does happen after petroleum maturation? The source rock goes under great pressure during petroleum generation, organic matter expansion, continuous compaction, clay dehydration and overburden pressure. These factors will produce huge pressure resulting in micro-fracturing in the source rock. The petroleum will escape through these The micro-fractures! movement of petroleum from the source rock to a permeable carrier bed is called: Primary migration. The carrier bed characteristics 1. Porous (has high porosity). 2. Permeable (has high What is porosity? permeability). Porosity is the void spaces volume What is permeability? with respect to the rock volume Permeability is the connected void spaces that ease the fluids movement in the rock. Bottjer, R. J., Sterling, R., Grau, A., & Dea, P. (2011). Stratigraphic relationships and reservoir quality at the Three Forks–Bakken http://www.dartmouth.edu/ Unconformity, Williston Basin, North Dakota. Carrier bed = Reservoir The carrier bed is also called Reservoir Reservoir is the storage of petroleum Reservoir might be sandstone or limestone. When does petroleum migration stops? A secondary migration might occur through the carrier beds, only if no barrier (Trap) stops petroleum from movement. So migration stops only if trap exists. Trap is non-permeable formation that will not permit petroleum to pass through.  Traps A trap is a place where oil and gas The traps are divided into two main types: accumulates. 1. Structural: formed by tectonics In general it is an area where porous Examples: reservoir rocks are covered by Fold (anticline fold: in the shape of small letter n). impermeable rocks which act as a Fault seal. 2. Stratigraphic: formed by erosion and diverse types of rocks. A hydrocarbon trap is required in Examples: order to exploit the oil and gas Pinch out reservoir. Unconformity Traps Structural trap examples https://www.e-education.psu.edu/png301/node/8 http://www.geologyin.com/2014/12/hydrocarbon-traps.html Traps Stratigraphic trap example: Stratigraphic trap example: pinch out unconformity https://petgeo.weebly.com/stratigraphic-trap.html Petroleum system components Component Function 1. Source rock (oil shale) Generation of petroleum 2. Reservoir rock (carrier Storage of petroleum porous bed) 3. Trap (seal, cap rock) Accumulation of petroleum in certain location and preventing further migration Petroleum and Gas Exploration 1. Field studies: collecting rock samples from the outcrops and studying them. 2. Aerial photography: photos taken from an aero-plane. 3. Remote sensing: satellite images are used in understanding the regional geology of large area. 4. Topographic maps: elevation maps. 5. Data compilation: collecting data from the previous four steps on a map. 2- Coal Coal is a sedimentary rock which derived from plants texture. There are different plant textures that might form coal. If these textures were with sufficient quantity, buried and preserved, subjected to enough temperature and pressure then coal would form. 2- Coal Different amount of heat will result in different amount of carbon content in the resulted coal and this will affect coal quality. Also impurities in coal will affect coal quality. Therefore, coal quality is evaluated depending on heat content and impurities! There are two ways to measure coal quality: coal rank & coal grade. Coal rank Coal rank is a measure of the heat content of the coal. This is related to % Carbon. Carbon rank is measured by a unit named: British Thermal Unit (BTU). Some plant textures capture more heat than the others and so contain more %carbon. For example peat texture contains 20% carbon whereas anthracite contains 94% carbon. As heat content increase, the % carbon increases and so the BTU increases and the coal quality is considered better. Coal grade Coal Grade: is a measure of the https://www.britannica.com/science/acid-rain purity of the coal. Coal grade assessment is focusing mainly on two parameters: sulfur content and ash content. Sulfur is not preferable in coal, because it raises to the atmosphere as SO2 while burning coal, and causes acid rain. Acid Branches from a tree in Germany's Black Forest rain would damage vegetations, show needle loss and yellowed boughs caused by acid rain. wild life and aqua life. Coal grade Ash is also not preferable in coal and lowers the air quality. Ash is the non-combustible material in coal. The ash content lowers the heat content of the coal because this material does not burn. It also causes disposal problems. These materials may have been deposited with the coal, or mixed with the coal when it was mined. Session 2 Renewable Energy Sources Renewable energy sources Examples: 1. Solar energy 2. Wind energy 3. Tidal energy 4. Geothermal energy 5. Hydropower (water energy) We will focus as geologist on the last two energies! Geothermal energy Geothermal energy is found in: 1. Geologically active areas (usually actively volcanic) where heat from near- surface magmas can reach the surface through the thin overlying rocks. Groundwater in these areas is heated to steam. The steam can be used to power electrical generators. Example: Japan 2. Radioactive areas where heat is produced through the decay of radioactive isotopes. Example: Mubazzara area in Hafit Mountain, Al https://www.energy.gov/eere/articles/geothermal-energy-glance-back-and-leap-forward Ain (Saibi et al., 2018). Hydropower (Water energy) Energy may be collected from surface waters as they flow from high to low areas. https://www.statkraft.com/energy-sources/hydropower/the-glaciers-inner-energy/ For example: Rivers are commonly faster flowing in their headwaters. https://www.studentenergy.org/topics/hydro-power Glaciers melting from the mountain areas of ice. Hydropower In Norway, numerous http://www.opusenergyblog.com/dam-impressive-norway-leads-europe-for-hydropower/ hydropower plants benefit from the glaciers melting. Hydropower covers nearly all of Norway’s energy needs. Glaciers today cover about 1 % of Norway’s land area while fresh water covers 5 %. Reference: https://www.statkraft.com/energy-sources/hydr opower/the-glaciers-inner-energy/ Water system in nature Most of the fresh water on Earth occurs in the subsurface (groundwater). https://study.com/academy/lesson/what-is-an-aquifer-lesson-for-kids.html Water storage: The water reservoir is called aquifer. Aquifer input: The aquifer is recharged usually by precipitation. Aquifer output: The aquifer might The level at which all pores are fully loose water through evaporation, saturated of water is called Water Table. springs and other intersections with So the water table is the starting line of an surface. aquifer. The zone above the water table is saturated with air and water, and it is called vadose zone or aeration zone. = Aquifer End of Chapter 4