Quiz: Geological Traps and Reservoirs

What is the primary role of seals in petroleum geology?

• Enhancing reservoir pressure

• Facilitating hydrocarbon extraction

• Preventing vertical migration of hydrocarbons

• Creating structural traps

Answer explanation

Seals in petroleum geology primarily prevent vertical migration of hydrocarbons by acting as impermeable barriers, trapping the hydrocarbons in the reservoir rock.

Which of the following is NOT a key characteristic of a good seal?

• High Permeability

• Regional Continuity

• Good ductility

• Low Permeability

Answer explanation

High permeability is NOT a key characteristic of a good seal because it allows for the passage of fluids or gases, which is undesirable in a seal.

Capillary entry pressure is essential for evaluating a seal's:

• Thickness

• Color

• Sealing capability

• Porosity

Answer explanation

Capillary entry pressure is essential for evaluating a seal's sealing capability, as it determines the ability of the seal to prevent fluid or gas from passing through.

Juxtaposition seals are formed by the juxtaposition of different lithologies, creating:

• Permeable barrier

• Impermeable barrier

• Vertical migration

• Hydrocarbon accumulation

Answer explanation

Juxtaposition seals are formed by the juxtaposition of different lithologies, creating an impermeable barrier, which is the correct choice.

Porosity refers to the:

• Rock's ability to transmit fluids

• Percentage of pore space in a rock

• Force required for fluid entry

• Thickness of the seal

Answer explanation

Porosity refers to the percentage of pore space in a rock, making it the correct choice.

Which diagenetic process involves the dissolution of minerals at contact points under pressure?

• Compaction

• Pressure solution

• Cementation

• Dissolution

Answer explanation

Pressure solution involves the dissolution of minerals at contact points under pressure, making it the correct choice.

What is the common range of permeability for sandstones?

• 0.0001 - 0.1 mD

• 0.1 - 1,000 mD

• 1 - 10,000 mD

• 5% - 30%

Answer explanation

The common range of permeability for sandstones is 1 - 10,000 mD, which is the correct answer choice.

What impact does cementation have on permeability?

• Increases permeability

• Decreases permeability

• No impact on permeability

• Increases porosity

Answer explanation

Cementation decreases permeability by filling in the pore spaces, reducing the ability of fluids to flow through the rock or sediment.

Darcy's Law is used to calculate:

• Capillary entry pressure

• Porosity

• Permeability

• Compaction

Answer explanation

Darcy's Law is used to calculate permeability, which is the ability of a porous material to allow fluids to pass through it.

What are the two main classification of traps in petroleum geology?

• Structural traps and sedimentary traps

• Stratigraphic traps and diagenetic traps

• Anticlines and fault traps

• Structural traps and stratigraphic traps

Answer explanation

The two main classifications of traps in petroleum geology are structural traps and stratigraphic traps.