Test 1 Flashcards
Source
rock in which organic material is stored and is converted to hydrocarbons
Reservoir
porous and permeable rock capable of storing fluids such as natural gas and oil
Seals
impermeable rock that prevents fluid flow and is low in porosity and permeability
Trap
method of placing the seal on a reservoir
Maturation
thermal history of hydrocarbons
Migration
Path from source to reservoir
Timing
the migration must be of the right timing and the organic matter must have enough time and heat to effectively convert to hydrocarbons
Hunt, Andrews, and Cram all addressed which of the seven key elements of sedimentary basins
Trap
What did Cram suggest that was different from Andrews and Hunt
Stratigraphic Traps
Hydrocarbon
a molecule that contains only carbon and hydrogen atoms
nC21: Structure=?, Carbon Atoms=?
Structure: normal paraffin
Carbon Atoms: 21
Living organisms prefer even or odd numbers of carbons
odd numbers of carbons
Carbon Preference Index (CPI) for organisms: ? Hydrocarbons:?
Organisms: 4-5; Hydrocarbons: ~=1
Name of Structure, General Chemical Formula, H/C, and Saturated?

Naphthene, CnH2n, H/C=2, Saturated
Which major hydrocarbon structure has the highest H/C ratio?
Normal or Iso-Paraffin
What is the one stable aromatic?
Benzene
What type of water productivity will preserve the most organic material?
High water productivity
What kind of sediment grain size will preserve the most organic material
small (clay)
What type of sediment mineralogy will preserve the most organic material?
clay
What kind of energy EOD will preserve the most organic material?
low energy
What amount of oxygen will preserve the most organic material?
an anaerobic environment
90% of the organic matter preserved in sediments is insoluble _____.
Kerogen
10% of the organic matter preserved in sediments is soluble _____.
Bitumen
A sample of organic matter is mostly carbohydrates, proteins, and lignin. Is this material soluble or is it insoluble in organic solvents such as benzene or methanol?
Insoluble
How does dissolved organic matter become incorporated into sediments?
Winnowed organic material is adsorbed by clays.
Of the three forms of organic matter that are found in ocean water, which is most abundant
Dissolved
Briefly define TOC
Total organic Carbon: the percent of original organic carbon in a substance
Fragmental reservoir rocks are aggregates of one or more of the following components:
a. Grains
b. Matrix
c. Cement
Composition or Mineralogy (how many?) of Fragmental Reservoir Rocks vs. Chemical Reservoir Rocks
Fragmental Reservoir Rocks: more than one
Chemical Reservoir Rocks: micro-mineralization
Texture of Fragmental Reservoir Rocks vs. Chemical Reservoir Rocks
Fragmental Reservoir Rocks: Clastic/Fragmental
Chemical Reservoir Rocks: Crystalline
Primary porosity of Fragmental Reservoir Rocks vs. Chemical Reservoir Rocks
Fragmental Reservoir Rocks: yes
Chemical Reservoir Rocks: no
Example of a reservoir rock of Fragmental Reservoir Rocks vs. Chemical Reservoir Rocks
Fragmental Reservoir Rocks: Sandstone
Chemical Reservoir Rocks: Limestone
How are fragmental (clastic) rocks formed from sediments? Name the three different processes involved in lithification in the correct order.
- Burial
- Compactions
- Cementation
The name of a sandstone that has at least 25% matrix
Graywacke
Is the porosity of a limestone formed from the remains of micro-organisms primary or secondary porosity?
Primary
Is the porosity of a chert layer formed by natural fractures primary or secondary porosity?
Secondary Porosity
Name one process that causes the secondary porosity of a rock to be greater than the primary porosity.
Fracturing/Faulting
Name one process that cause the secondary porosity to be less than the primary porosity.
Recrystallization
Explain why the porosity of chemical reservoir rocks is enhanced just below an unconformity surface.
Just below and unconformity is where a lot of erosion happened so some rock may have been dissolved allowing greater porosity.
Explain the difference between elastic compaction and plastic compaction.
Elastic can retain its original form, plastic cannot
Describe on cause of fracturing that has nothing to do with either folding or faulting
Decompression
Why does pin-point porosity form?
Pin-point porosity forms where calcite replaces other minerals in limestone through the process of dolomitization.
What are the Reservoir Facies and Seal Facies of Meandering Streams?
Reservoir Facies: point bar deposits
Seal Facies: flood plain
What are the Reservoir Facies and Seal Facies of a Braided Stream?
Reservoir Facies: Channel bar deposits
Seal Facies: none
What are the Reservoir Facies and Seal Facies of Desert Ergs (Sand Seas)?
Reservoir Facie: dunes
Seal Facie: none
What are the Reservoir Facies and Seal Facies of Barrier Islands?
Reservoir Facie: shoreface
Seal Facie: lagoons
What are the Reservoir Facies and Seal Facies of Deltas?
Reservoir Facie: distributor mouth deposits
Seal Facie: delta plain
What are the Reservoir Facies and Seal facies of Tidal Flats?
Reservoir Facie: Subtidal
Seal Facie: Supratidal
What are the Reservoir Facies and Seal Facies of Deep Sea Fans?
Reservoir Facie: turbidity sands
Seal Facie: marine clays/shales
Give an example of a shoe-string sand deposit
Meandering Stream
Would you be able to distinguish between an upper delta plain deposit and a meandering stream deposit from subsurface cores?
No
Give an example of an environment of deposition where the vertical sequence lines upwards.
Braided Stream
Give an example of an environment of deposition where the vertical sequence coarsens upwards.
Deltaic, Barrier Island
What is the primary porosity of a limestone, and would secondary porosity be greater than or less than the primary porosity?
Primary porosity is when it was deposited (low?); greater
Name any one place on Earth where an eolian environment of deposition is locate
Desert (Sahara Desert)
Compare the energy conditions in the environment of deposition for a reservoir rock to the energy conditions in the environment of deposition for a source rock.
Energy for source rock: high
Energy for reservoir rock: low
Name one environment of deposition that has a linear trend parallel to the coastline.
Barrier Islands
Name one environment of deposition that has a linear trend perpendicular to the coastline.
Stream
Name one prominent landform that one might find in an eolian environment of deposition.
Dune
Of all the carbonate MINERALS, which is the most soluble in water?
Aragonite
What MINERAL is the most common cement?
Quartz