PETE 4088. Homework II. From Bassiouni text.

1. A gas well in the Muddy Ridge field, Wind River Basin, Wyoming, produces from a tertiary sand formation characterized by the following data.

Depth = 2122 feet

Porosity = 21%

Resistivity = 43 ohm-m

Rw (from a water sample) = 3.28 ohm-m at 68 degrees F

Formation temperature = 90 degrees F

Qv (from core samples) = .3 meq/ml

Estimate the gas saturation assuming clean sand

Estimate the gas saturation using the Waxman Smits equation

2. X-ray diffraction analysis of a sandstone core sample shows that it contains 18% clay by weight. The clay consists of 10% smectite and 8 % illite. The sandstone has a total porosity of 14%. Calculate the Qv.

3. Describe in one paragraph why sandstones containing clay have a higher conductivity than clean sands.

4. What is the term B related to in the Waxman Smits model? How would you determine it to use in a log analysis?