RESERVOIR Flashcards
What is a porous and permeble rock unit capable of storing and containing hydrocarbons coming from the source rock?
Reservoir Rock
What rocks can act as reservoir?
Any rock as long as it is porous and permeable
What are the most abundant reservoir rocks?
Sandstones
Carbonates
Porosity of a reservoir rock?
20-50%
Permeability of a reservoir rock?
K=10mD to >1000mD
Most productive reservoir
Carbonates
Porosity of Sandstone
25-40%
Porosity of carbonate
10-50%
Pores that communicate with other by more than one throat passage
Caternary Pore
Pores that have only one throat passage
Cul de Sac Pore
Pore with no throat passage
Closed Pore
Primary vs Secondary Porosity
Primary refers to pores formed during rock formation during deposition and sedimentation
Secondary refers to pores formed after deposition
Porosity as a function of sorting
The more well sorted, the higher the porosity since there will be more grain contacts that grain filling
Refers to the SPACING or DENSITY PATTERNS of GRAINS in a sed rocks and is a function of GRAIN SIZE, GRAIN SHAPE and DEGREE OF COMPACTION
Grain Packing
Which grain arrangement will give the least porosity?
Rhombohedral
Which grain packing will give the most porisity?
Cubic
Units of permeability
Millidarcy (for reservoirs)
Permeability as a function of Grain Size
As grain size decreases, permeability decreases (Direct)
permeability as a function of sorting
The more poorly sorted a rock is the lower its permeability
Which is more permeable sandstones in Pontbars, beaches, or dunes?
Pointbars
Beaches
dunes
Type of reservoir created by folding of thich compacted reservoir rocks with accumulation under an anticline or some trap and hrdrocarbons would better separated due to lower temperature and pressure
Shallow Reservoir
A reservoir created by servere faulting in which hydrocarbons would be less separated with more gas in solution and oil of reduced viscoity because of higher temp. Often reduced porosity and permeability
Deep reservoir
Well sorted sandstones
Clean sands
Poorly sorted sandstones because of significant amount of silt and clay sized particles
Dirty Sands
Areas of Sandstone Accumulation
River Channels
Deltas
Beaches
Lakes
Submarine Fans
Porosity type of carbonates when pores are larger than grains
Vuggy
Pores between grains
Intergranular
Pores within grains
Cellular
Latitude of Carbonate formation
low latitudes 30 deg N and S of equator
Diagenetic processes which enhances secondary poroisty
Dolomitization
Facturing
Dissolution
Recrystallization
Country which has granite as reservoir
Vietnam
Enhancement of unconventional reservoir by injecting HCL thus dissolvig cement of the reservoir
Acidization
A method which liquid with sand is driven off into the reservoir under high pressure
Hydraulic Fracturing
Fracking
