1. Petroleum Geology and the Permian Basin
Andrew McCarthy
Concho Resources

2. Petroleum System Source: organic-rich mudrock Heat (burial) and time
Reservoir: porous rock
Seal: low-permeability rock
Trap

3. Source 3,850,000 EJ burial Sol (our sun) Fusion (of hydrogen
and helium)
burial
3,000 EJ
Earth
3,850,000 exajoules per year – Solar radiation
3,000 exajoules per year – captured by plant life
500 exajoules per year – total human use (fossil, nuclear, etc.)

4. + Source Shale: high organic material Gas (methane, ethane, propane)
H2S
CO2 N2 +
Kerogen
Heat and pressure
Kerogen: geo-plastic or geo-chocolate.
Lipids, proteins, carbohydrates
Texas tea
(light, sweet crude)

5. How much heat? Low temps yield nothing: <60 C
High temps yield oil: 60C-120+C
Higher temps yield gas: 120+C

6. 100% natural and organic Oil is 100% natural and organic
Yummy!
Oil is 100% natural and organic
95%++ of all oil ever generated has been naturally leaked to the surface
Millions of natural oil seeps exist around the planet, many under the oceans
Natural
Oil seeps
(BP not
Involved)
Not
Iced
tea

7. An oil reservoir at the surface
Oil reservoirs are exposed and eroded away. The light oil is biodegraded, tar remains.

8. OK. So far we have: Source Heat and time
Now we need a reservoir, a seal, and maybe a trap

9. Reservoir The first key to a reservoir rock is porosity intergranular
fracture

10. Got porosity?

11. Reservoir
The second key to a reservoir rock is permeability

12. Seal We need something to slow the upward migration of oil and gas.
A seal will do: it’s a layer of very low permeability.
Microscopic view of clay layers
Imagine if this were clay…

13. Traps
Required for conventional reservoirs…

14. A very conventional petroleum system:
Concho
oil
sealing shale
sand
organic shale

15. Today: Unconventional plays
Tight carbonate (seal/frac barrier)
Organic mudstone, silty shale, with varying carbonate and silica content
1 source
2 reservoir
3 seal
Tight carbonate (seal/frac barrier)

16. “Shale” plays What is shale? Silt vs. clay
Mudrocks (silt, clay, organics, carbonate)
Needs help: must be fracture-stimulated (poor natural permeability)
Shale rocks can serve as
Source
Reservoir
Seal

17. The Permian Basin

18. Geologic Time

19. Today
Active petroleum systems

20. Basins basin Low areas; tend to fill with sediment
Typically covered with water (ocean, sea or lake)
Nature’s landfill
Rivers
Coral reefs
Wind blown
Pelagic
rain
basin
deep basin
slope
shelf

21. Before the Permian Basin
Shales: Devonian Mississippian Barnett
Before 370 Ma (Devonian)
Ron Blakey, Colorado Plateau Geosystems, Inc.

22. Early Permian Basin 315 Ma Late Miss/Early Penn time Shale deposition
Ron Blakey, Colorado Plateau Geosystems, Inc.

23. Late Permian 255 Ma Carbonates (shallow marine carb factory)
Later, evaporites
Ron Blakey, Colorado Plateau Geosystems, Inc.

24. Sources
Organic-rich shales

25. Reservoirs
*Just about everything!
carbonates
sands
Shale/silt

26. What does a geologist do?
Exploration very little data!
Seismic, basin geochem, remote sensing
Everything changes with the first well
Development increasing amounts of data!
Well logs, core, production data
Operations
Day-to-day drilling
When do we have “the answer”?

27. Thank you.