Shaly Sands Theory

Question 1

Sand, silt and clay are not lithologies! They are size parameters. What are their grain sizes?

Answer 1

Sand: >62 microns
Silt: 4-62 microns
Clay: <4 microns

Question 2

The mineral make-up of a shale depends on its …

Answer 2

source

Question 3

The grain size distribution of a shale depends on …

Answer 3

the distance from the river mouth

Question 4

What equation describes thickness of CBW?

Note: this equation is used to correct for CBW in Hg-Air cap curve

Answer 4

Hill-Shirley-Klein

Question 5

Give the range of CEC values by clay type

Answer 5

Kaolinite: 3-15 meq/100g
Chlorite: 1-30 meq/100g
Illite: 10-40 meq/100g
Smectite: 80-150 meq/100g

dependent on exchange capacity of cations (Mg, Al)

Question 6

What did Juhasz assume in his model?

Answer 6

• clay type doesn’t vary (same in shales as in sands)

- shale is 100% water-bearing

Question 7

What does Qv depend on and what relationship does Qv have with it?

Answer 7

Qv decreases with increasing porosity (less surface area to volume ratio)