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Unformatted text preview: p rock): A relatively impermeable rock that forms a barrier, cap or seal above and around reservoir rock so that fluids cannot migrate beyond the reservoir. The permeability of a cap rock must equal zero. Some examples are Shales, Evaporites such as Anhydrite & Salt, & Zero-porosity Carbonates. 5‐Traps: It is configuration of rocks suitable for containing hydrocarbons and sealed by a relatively impermeable formation through which hydrocarbons will not migrate. Types of Traps: A-Structural Traps: It is formed where the space of petroleum is limited by a structural feature • Anticline traps: trap whose closure is Fault trap Anticline trap controlled by the presence of an anticline. • Fault trap: in which closure is controlled by the presence of at least one fault surface. B‐Salt domes traps: Salt domes traps are caused when plastic salt is forced upwards through layers C‐Stratigraphic traps: It is the trap created by the limits of reservoir rock itself, without any structural control. It is formed by changes in rock type or pinch-outs, unconformities, or sedimentary features such as reefs. • Pinch-out trap: The termination by thinning or tapering out ("pinching out") of a reservoir against a nonporous sealing rock creates a favorable geometry to trap hydrocarbons. • Unconformity trap: trap whose closure is controlled by the presence of an unconformity. • Reef trap: sedimentary rock, most commonly produced by organisms that secrete shells such as corals. Because the rocks that surround reefs can differ in composition and permeability, porous reefs can form stratigraphic traps for hydrocarbons. D‐Combination Traps: It is a combination trap is where two (or more) trapping mechanisms come together to create the trap. Unconformity Pinch‐out Salt dome Reef 31 Geology & Geophysics in Oil Exploration Mahmoud Sroor Geology & Geophysics in Oil Exploration Ch5: Seismic Survey Seismic surveys use reflected sound waves to produce a scanning of the Earth’s subsurface. Seismic surveys can help locate ground water, are used to investigate locati...
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This note was uploaded on 01/05/2011 for the course GEOL 1 taught by Professor Jenniferalford during the Spring '10 term at Indian Institute of Technology, Roorkee.
- Spring '10