Mixing oil and water: Reinforcing groundwater concepts through comparisons with petroleum migration

Lawrence D. Lemke
Wayne State University
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A guided brainstorming exercise for discovering similarities and differences between groundwater flow and oil migration. It provides an opportunity for students to make connections between hydrogeology and petroleum geology applications and to consider controls on single and multiphase flow fluid behavior in porous media.

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Upper division undergraduate course in hydrogeology, petroleum geology, or economic geology. Upper division undergraduate or graduate level courses in single and multiphase subsurface flow and transport.

Skills and concepts that students must have mastered

Students should have mastered:

  • concepts of porosity and permeability
  • Darcy's law
Students should have been exposed to concepts of:
  • confined and unconfined aquifers
  • fluid saturation
  • water table or oil water contacts
  • wetting and nonwetting fluids

How the activity is situated in the course

This activity can be used as part of a lecture or as an introductory activity during a lab. It requires active student participation and can therefore be used to breakup the pace of a lecture. The activity also provides the opportunity for professors to learn from their students.


Content/concepts goals for this activity

- single and multiphase flow
- relative permeability
- driving forces for fluid flow

Higher order thinking skills goals for this activity

- knowledge: exposure to applications outside groundwater hydrology
- application: using concepts and information in new situations
- synthesis: relating knowledge from several areas

Other skills goals for this activity

- discussion
- brainstorming
- hydrogeologic intuition development

Description of the activity/assignment

In this exercise, students use their intuition to enumerate similarities and differences between groundwater flow and oil migration. The activity is divided into two parts: (1) brainstorming of ideas, and (2) an expanded discussion of selected topics. The instructor begins by briefly reviewing the Rules of Brainstorming and then soliciting answers to a question such as: "How is the flow of groundwater in an aquifer similar to or different from the movement of oil in a petroleum reservoir?" The instructor records the similarities and differences suggested by students in two lists. After a sufficient quantity of responses has been gathered, the instructor chooses certain ideas for closer examination and discussion. (The instructor may decide on target topics in advance, or may choose to 'go with the flow' to explore interesting ideas that emerge from the students.) The activity gives students the opportunity to connect the disciplines of hydrogeology and petroleum geology, with particular emphasis on the concepts of multiphase flow, relative permeability, and saturation distributions at the water table and oil-water contacts.

Determining whether students have met the goals

Evaluation of student learning can be accomplished using true/false or short answer questions on subsequent quizzes or exams. Example questions:

1. State two ways in which an oil reservoir is similar to a confined aquifer:
- upward movement of fluid out of the reservoir/aquifer is impeded by a confining layer
- fluid pressures contribute to head values that exceed the elevation of the top of the reservoir/aquifer

2. State two ways in which an oil reservoir is similar to an unconfined aquifer:
- there is a free fluid surface at the top/base of the aquifer/reservoir
- transitional saturations occur above the capillary fringe and oil-water contact.

3. The relative permeability of oil and water is generally less than 1.0 when oil and water share the interconnected pore spaces in a rock. (true)

4. Density-driven fluid movement is generally downward in aquifers and upward in petroleum reservoirs. (true)

More information about assessment tools and techniques.

Teaching materials and tips

Other Materials

Supporting references/URLs

Craft, B.C. and M. Hawkins, 1991, Applied Reservoir Engineering, 2nd ed., revised by R.E. Terry, Prentice-Hall, Inc., Englewood Cliffs, New Jersey, 431 pp.

Dickey, P.A., 1979, Petroleum Development Geology, PPC Books, Tulsa, Oklahoma, 398 pp.

Selley, R.C., 1998, Elements of Petroleum Geology, Academic Press, San Diego, California, 470 pp.

Online glossaries of oil reservoir terminology: