Page 273 - Geology of Carbonate Reservoirs

254 SUMMARY: GEOLOGY OF CARBONATE RESERVOIRS

REVIEW QUESTIONS

8.1. Which wireline logs are most useful for determining facies characteristics in

carbonates? Explain.

8.2. Are lithological logs based on examination of cuttings just as useful as “ lith
logs ” based on cores? Explain.
8.3. How much and what kind of information is necessary to identify any one of

the seven standard depositional successions?
8.4. Porosity and permeability commonly exhibit a linear relationship on semilog

plots. Is that always true in carbonate reservoirs? Explain.

8.5. What did Focke and Munn ( 1987 ) discover about the relationship between
carbonate pore types and petrophysical characteristics?
8.6. Would regional, field, or reservoir scale data be most helpful for developing

sequence - stratigraphic models of carbonate depositional systems?

8.7. Which of the seven standard depositional successions are most likely to be
depositional reservoirs?

8.8. Assume that a porous and permeable depositional reservoir trend extends

along a depositional strike for many miles. Would you expect the entire trend
to be productive? If not, how would you choose exploration targets within the
trend?
8.9. A productive oolite grainstone facies with characteristics like those of the

slope - break standard succession was found in an outer - ramp environment
otherwise dominated by mudstones and wackestones. How do you explain the
presence of the grainstone succession?

8.10. Porosity in the oolite grainstone from Question 8.9 was found to be a solu-

tion - enhanced intergranular hybrid (Type IA). What possible depositional and
burial history could lead to the formation of this type of porosity in an outer -
ramp environment?

8.11. What conditions are necessary to create and preserve high values of interpar-

ticle porosity in chalks?

8.12. What clues in carbonate reservoir rocks might indicate that diagenesis took

place in or near a paleo water table?

8.13. What is a “ slice map ” and what purpose does it serve?

8.14. When more than one episode of fracturing has occurred and several sets of

fractures can be identified by image logs, which are the fractures most likely
to influence production and why?