CPG Petroleum Geology & Reservoir Characterization 4

Question 1

In a delta system, which depositional environment typically produces the best reservoir quality sand due to high-energy reworking?

Accepted Answer

Distributary mouth bar

Answer

Distributary mouth bars are reworked by wave and current energy as river sediment enters the basin, producing well-sorted, clean sands with excellent reservoir quality.

Question 2

The concept of 'effective porosity' differs from 'total porosity' in that it excludes:

Accepted Answer

Clay-bound water and isolated pores

Answer

Effective porosity excludes clay-bound water and isolated (non-connected) pore space, representing only the porosity available for fluid flow.

Question 3

Which tectonic setting is MOST favorable for the formation of foreland basin petroleum systems?

Accepted Answer

Continental collision and thrust belt systems

Answer

Foreland basins form in front of thrust belts during continental collision, providing thick sedimentary sequences with good source, reservoir, and seal combinations.

Question 4

What does a negative acoustic impedance contrast at a reservoir boundary indicate on a seismic section?

Accepted Answer

Velocity and/or density decrease downward across the boundary

Answer

A negative acoustic impedance contrast means the product of velocity and density decreases across the boundary downward, producing a phase reversal in the reflected seismic wavelet.

Question 5

The Laramide Orogeny is important for Rocky Mountain petroleum geology because it:

Accepted Answer

Formed structural traps through basement-involved reverse faulting and folding

Answer

The Laramide Orogeny created basement-cored uplifts and adjacent basins through thick-skinned reverse faulting, forming the structural traps that host many Rocky Mountain oil and gas fields.

(CPG) Certified Petroleum Geologist Practice Test

(CPG) Certified Petroleum Geologist Practice Test

CPG Petroleum Geology & Reservoir Characterization 4