A Model Oil Well

Objective:

To demonstrate how a fluid such as oil or water can flow out of an underground reservoir and up to the surface. To discover the characteristics of a reservoir (porosity/permeability) and the important characteristics of a seal. To investigate removal of fluids using a well. Background Information:
The Theory and Principles Clastic sedimentary rocks are normally filled with fluid. At the time of deposition, water associated with the sediment grains is trapped within the clastics. Burial and subsequent induration will seal much of the water within the sediment. Generation and the migration of hydrocarbons will often displace the water where porosity and permeability permits. Movement of fluids within a sediment layer which possesses permeability is primarily controlled by pressure. Fluids will flow upward (toward lower pressure) until they reach an impermeable layer (seal).

The construction of the model will help explain the concepts of porosity and permeability, seals, and aquifers (reservoirs). The experiment will reveal the need for the fluid to have a pathway provided by the spaces between the sand grains which will permit its movement. The porosity that is in evidence in the sand is sharply contrasted with the students' perception of permeability in the Plasticine layer. The role of hydrostatic head and pressure differential may be explored. The obvious link is that with increased pressure there will be increased flow. The concept of pumping of the oil and natural gas should be explored.

Materials: a clear container preferably 12-15 cm (minimum) across the bottom (large beaker);
large, clear, plastic pop bottle, small aquarium
2 glass tubes or drinking straws
a funnel
a piece of plastic (rubber) tubing which will fit both
the tubing (straws) and the funnel
aquarium gravel
sand
Plasticine or "Play Dough" to simulate clay
water (food colouring may be added)
Procedure: Fit one tube (straw) with the rubber tubing and funnel. Place the tubes at opposite sides of the container, next to the outside so the fluid may be observed. Place the aquarium gravel (coarse sand) in the bottom of the container and fill to a height of 8-10 cm. Carefully pack a layer of "clay" (1 cm is sufficient) on top of the gravel and seal around each piece of tubing and against the side of the container. Add a layer of sand (6-8 cm) on top of the "clay" layer.

Fill the funnel with water while holding the funnel below the level of the gravel. Slowly raise the funnel and observe the flow of water. Add more water as needed and continue to raise the funnel. Observe the results. Using your mouth force air into the funnel and observe what happens. Blow harder and observe.

Questions | Expected Answers

Last Modified: 2004-12-10