Petroleum Geology (Introduction to Reservoir Properties) Final Examination

reservoir rock

a place that oil migrates to and is held underground.

• Sandstones

• Limestone and /or Carbonate rocks

Examples of reservoir rocks includes:

Coring

processes used to recover formation samples from petroleum reservoirs.

the capacity and ability of the reservoir rock to store and conduct petroleum fluids through the matrix

Physical sample of reservoir rock core is essential to evaluate the two most significant characteristics:

1. Framework

2. Matrix

3. Cement

4. Pores

Four major components of sandstone

3 to 7

90

Core diameters are typically from _ to *_* inches and are usually about ___ feet long

Sidewall Sampling Gun/Tool

can be used to obtain small plugs from the formation.

Sidewall Sampling Gun/Tool

The tool is run on a wireline after the hole has been drilled.

Sidewall cores

useful for identifying hydrocarbons zones, when viewed under UV light.

Whole Core

Provides larger samples

Whole Core

Better and more consistent representation of formation

Whole Core

Better for heterogeneous rocks or for more complex lithologies

Plugs or Sidewall Cores

Smaller samples

Plugs or Sidewall Cores

Less representative of heterogeneous formations

Plugs or Sidewall Cores

Within 1 to 2% of whole cores for medium-to highporosity formation

Plugs or Sidewall Cores

In low-porosity formations, Φ from core plugs tends to be much greater than Φ from whole cores

Plugs or Sidewall Cores

Scalar effects in fractured reservoirs

• Porosity

• Horizontal permeability to air

• Grain density

INFORMATION FROM CORES

Standard Analysis

• Vertical permeability to air

• Relative permeability

• Capillary pressure

• Cementation exponent (m) and saturation exponent (n)

INFORMATION FROM CORES

Special Core Analysis