Reservoir Characterization Flashcards
7 cards from real SPE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Reservoir Characterization flashcards as text
Which petrophysical parameter is defined as the ratio of pore volume to total bulk volume of a rock sample?
Answer: Porosity
Porosity is the ratio of pore volume to bulk volume, expressed as a fraction or percentage.
In a water-wet reservoir, where does water preferentially reside?
Answer: Contact with grain surfaces
In water-wet systems, water coats grain surfaces and occupies smaller pore spaces due to its affinity for the rock.
What does the term 'irreducible water saturation' (Swi) represent in reservoir engineering?
Answer: The minimum water saturation that cannot be displaced by hydrocarbons
Irreducible water saturation is the minimum water held by capillary and adsorptive forces that cannot be displaced by oil or gas.
Which log is most commonly used to identify lithology changes and correlate stratigraphic units across wells?
Answer: Gamma ray log
The gamma ray log measures natural radioactivity, distinguishing shales (high GR) from clean sands or carbonates (low GR) for lithology and correlation.
What is the primary purpose of a repeat formation tester (RFT) or modular dynamic tester (MDT) in well logging?
Answer: Obtain downhole fluid samples and pressure measurements at discrete depths
RFT/MDT tools set packers to seal off intervals, measure formation pressure, and collect representative fluid samples at multiple depths.
In reservoir characterization, what does 'facies' refer to?
Answer: A body of rock with defined characteristics reflecting its depositional environment
A facies is a distinctive rock unit defined by its lithology, texture, fossils, or sedimentary structures that reflects a specific depositional environment.
Which method uses the relationship between capillary pressure and fluid saturation to estimate reservoir rock quality and pore structure?
Answer: Mercury injection capillary pressure (MICP) analysis
MICP forces mercury into core plugs at increasing pressures, revealing pore throat size distribution and capillary entry pressures.