1Fossil Fuel ResourcesExam next TuesdayFebruary 14Bring Scantron and Review QuestionsSedimentary rocksAbout 75% of all rock outcrops on the continentsImportant to reconstruct much of Earth's historySediment is derived from weatheringWeatheringTwo kinds of weathering • Mechanical• ChemicalMechanical WeatheringChemical weathering• Chemical changes of minerals• Removing or adding elements • Most important agent is water Rates of weatheringImportant factors• Rock characteristics• Climate2Sedimentary RocksTwo main types• Clastic (or detrital) —Deposition of particles• Chemical—Precipitation from water (includes rocks formed by organisms)Types of Clastic Rocks• Shale (most abundant)• Sandstone• ConglomerateShale• Most common type of clastic rock• Very fine grained sediment• Usually gray• Tendency to split along planes (fissile)Shale with plant fossilsSandstone• Composed of sand-size particles• Environments include•Beach •River •Shallow sea•DunesSandstone3Conglomerate• Particles larger than 2 mm• Usually rock fragmentsConglomerateChemical rocksDissolved material precipitates to form sedimentary rock•Physical processes•Life processes (biochemical origin) Chemical rocks• Limestone– calcium carbonate– 90% precipitated by organisms• Most common type of chemical rockCoquina Close up of coquina4Fossiliferous limestoneChalkChemical rocksDirect precipitation from water• Chert, flint, jasper, opal or agate• Evaporites—Salt, Gypsum• Hotspring depositsRock saltFeatures of sedimentary rocks• Bedding and bedding planes• Size, shape and distribution of grain sizes• Fossils • Porosity• PermeabilityEconomic importance•Coal•Petroleum and natural gas • Sources of iron and aluminum5Petroleum Requirements• Source• Cooking• Reservoir•TrapHydrocarbon System• http://www.priweb.org/ed/pgws/systems/systems_home.htmlSOURCES• Shale with organic material• Gooey sludge on ocean floorDiatoms• Planktonicorganisms• Probable source of petroleumhttp://www.priweb.org/ed/pgws/systems/energy_capture/capture.htmlhttp://www.priweb.org/ed/pgws/systems/source/source.htmlCOOKING• Just right temperature• Just right pressure• Just right timeRESERVOIR• Permeable • Porous• Usually a sedimentary rock6PERMEABLE• Permits fluid throughflow• Nylon scrubbiePOROUS• Has open space• SpongeRESERVOIR• Permeable • and Poroushttp://www.priweb.org/ed/pgws/systems/reservoir/reservoir.htmlTRAP• Impermeable• Shale, commonly• (Usually not source shale)TrapAlmost no permeability or pore spacehttp://www.priweb.org/ed/pgws/systems/seal/seal.htmlSTYLES OF TRAPS• Structural• Stratigraphic7STRUCTURAL TRAPS• Anticline• Fault•Overthrust•Salt DomeANTICLINE TRAP• Reservoir sand• Capping shale • Arched foldPlummer, McGeary Physical Geology, 2nd, Wm. C. Brown Co., 1979FAULT TRAP• Reservoir exists• Fault creates trapPlummer, McGeary Physical Geology, 2nd, Wm. C. Brown Co., 1979OVERTHRUST TRAP• Reverse fault• Both fold and fault trapsPlummer, McGeary Physical Geology, 2nd, Wm. C. Brown Co., 1979SALT DOME TRAPPlummer, McGeary Physical Geology, 2nd, Wm. C. Brown Co., 1979SALT DOME TRAP• Rising dome deforms beds• Salt and shale impermeablePlummer, McGeary Physical Geology, 2nd, Wm. C. Brown Co., 19798STRATIGRAPHIC TRAPS• Sand pinch• Lens• Unconformity• ReefSAND PINCH TRAP• Deposition of sand • Shale deposited above sand–Deltas– Invading seasPlummer, McGeary Physical Geology, 2nd, Wm. C. Brown Co., 1979Ganges Deltahttp://eol.jsc.nasa.gov/debrief/STS066/rep2.htmSAND LENS TRAP• Channel sand• Shifting channel of river• Shale abovePlummer, McGeary Physical Geology, 2nd, Wm. C. Brown Co., 1979Sand lensTraps frommeanderingstreamshttp://www.priweb.org/ed/pgws/systems/traps/strat/strat_traps.htmlUNCONFORMITY TRAP• Reservoir rock tilted and eroded• Impermeable rock deposited above erosion surfacePlummer, McGeary Physical Geology, 2nd, Wm. C. Brown Co., 19799REEF TRAP• Porous reef core• Flanks also porous• Impermeable shale capPlummer, McGeary Physical Geology, 2nd, Wm. C. Brown Co., 1979Alberta Reef depositLOCATIONS OF FUELS• Middle East• North AmericaAmerican Oil FieldsMAJOR OIL FIELDS IN NORTH AMERICAPlummer, McGeary Physical Geology, 2nd, Wm. C. Brown Co., 1979TITUSVILLE, PA• Oil Creek Valley in the 1860s• Phillips well (rt) 4000 bbl/day• Woodford well (lt) 1500 bbl/dayhttp://www.priweb.org/ed/pgws/history/pennsylvania/tarr_farm.htmlOrigin of Pennsylvania Oil• Delta deposits of gooky mud with organics• Overlain by river sand• Sea invades and covers all with shale• Pennsylvanian Period• http://www.priweb.org/ed/pgws/backyard/pennsylvania/pennsylvania_oil.html10Texas Oil• Lucas Gusher, 1901• Initial production 100,000 bbl/day• Salt dome trapshttp://www.priweb.org/ed/pgws/history/spindletop/spindletop.htmlBoiler AvenueOn Spindletopsalt dome at Beaumont, Texashttp://www.priweb.org/ed/pgws/history/spindletop/spindletop.htmlSignal Hill, Long Beach, CA1932http://www.priweb.org/ed/pgws/history/signal_hill/signal_hill2.htmlDrilling on the North SlopePlummer, McGeary Physical Geology, 2nd, Wm. C. Brown Co., 1979Drilling in the North SeaRocks and Fossils, Busbey, Doenraads, Willis and Roots, Fog City Press, 1997Top 10 Countries—Oil Statistics• Reserves• http://www.nationmaster.com/graph-T/ene_oil_res&int=10• Comsumption•
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