- Slides: 44
Fossil Sedimentary rocks record environmental information
Continental Shelf 10 -15 K feet of compacted sand mud
Lithification: Compaction and cementation At depth, Si. O 2 and Ca. CO 3 go into solution, water is driven out (dewatering). This solution permeates throughout open pore spaces, forming a cement.
Cemented Sandstone Si. O 2 cement
Cemented Limestone Ca. CO 3 cement
Classification of Sedimentary Rocks
Clastics Increasing water energy
Clastic Sedimentary Rock
Fast Stream Fast moving water does not allow clay-sized particles to accumulate. They stay in suspension. Larger particles, like pebbles, drop through the water column and accumulate.
Biogenic rocks - Limestone Accumulation of dead critters. Shallow, warm, marine environment.
Limestone Thin Section Fossils cemented together by Ca. CO 3 cement.
Biogenic rocks - Coal Accumulation of organic material in a swampy environment. Anaerobic, dark, murky water.
Lagoon Care for a swim?
Chemical rocks - Evaporite - Salt What happens when salty water evaporates?
Salt Flat Wet in the spring and early summer Water evaporates in late summer and fall
Chemical rocks - Chert Microcrystalline silica Deep water ocean environment, too cold for Ca. CO 3 precipitation.
Sea level facies change
Mud Sand North Carolina
Offshore Oil Rig
Oil Traps Oil & gas are less dense, so they migrate toward the surface.
Salt Dome Salt is very impermeable Salt is also less dense than the country rock, so it too is migrating toward the surface.
Maturation Given many thousands of years, a stack of mud and organic remains many kilometers thick may pile up on the sea floor, especially in nutrient-rich waters. Given enough time, the overlying sediments that are constantly being deposited will bury these organic remains and mud so deeply that they will eventually be turned into solid rock. It is believed that high heat and intense pressure help along various chemical reactions, transforming the soft parts of ancient organisms found in the deep-sea sludge into oil and natural gas. At this point, this ooze at the bottom of the ocean turns into source rock.
Reservoir Rock High porosity Low porosity Oil must be allowed to move between pore spaces: permeability
Stratigraphic Trap Oil migrates into ‘traps’
Oil rig: Gulf of Mexico
Gulf of Mexico 130 active drilling rigs 4, 489 producing oil wells 3, 813 producing gas wells
Worldwide Offshore Oil Rigs North Sea: 88 Gulf of Mexico 215 S. Asia: 25 Far East: 23 Latin America 109 Pacific Rim: 42 West Africa: 42 November 2001 Middle East: 33
Known Oil Reserves
Oil Consumption United States: 19. 6 million barrels per day. 25% of world total. World: 75 million barrels daily and rapidly increasing. How much is left? Forecasted at 40 years (2 K billion barrels).
World Oil Consumption
What A Barrel Of Crude Oil Makes (42 gallons) Product Gallons per barrel gasoline 19. 5 distillate fuel oil 9. 2 (Includes both home heating oil and diesel fuel) kerosene-type jet fuel 4. 1 residual fuel oil (Heavy oils used as fuels in industry, marine transportation and for electric power generation) 2. 3 liquefied refinery gasses 1. 9 still gas 1. 9 coke 1. 8 asphalt and road oil 1. 3 petrochemical feedstocks 1. 2 lubricants 0. 5 kerosene 0. 2 other 0. 3
Oil makes gas, right? Well… saccharine (artificial sweetener) roofing paper aspirin hair coloring heart valves crayons parachutes telephones bras transparent tape antiseptics purses deodorant panty hose air conditioners shower curtains shoes volleyballs electrician's tape floor wax lipstick sweaters running shoes bubble gum car bodies petroleum jelly tires lip balm house paint antihistamines hair dryers golf balls guitar strings dice pens insulation ammonia glycerin eyeglasses typewriter/ contacts computer life jackets ribbons insect repellent trash bags fertilizers rubber cement hair coloring cold cream movie film umbrellas ice chests ink of all types loudspeakers wax paper basketballs paint brushes footballs hearing aids combs/brushes compact discs linoleum mops fishing rods bandages rubber boots artificial turf water pipes cameras vitamin capsules glue motorcycle helmets shoe polish fishing lures caulking tape recorders stereos plywood adhesives TV cabinets toilet seats car batteries candles refrigerator seals carpet cortisone vaporizers solvents nail polish denture adhesives balloons boats dresses shirts (non-cotton) perfumes toothpaste roller-skate wheels plastic forks tennis rackets hair curlers Sorry, this is only a partial list… plastic cups electric blankets oil filters floor wax ping pong paddles cassette tapes dishwashing liquid water skis upholstery chewing gum thermos bottles plastic chairs transparencies plastic wrap rubber bands computers gasoline diesel fuel kerosene heating oil asphalt motor oil jet fuel marine diesel butane