ResGeo 202 Reservoir Geomechanics, Spring 2015, OpenEdX Homework 1 – Calculating Overburden Stress SOLUTIONS Click the right tab on the top of the page to download the solutions data
Part 1: Compute the overburden stress and overburden gradients a. Plot density vs. depth for each dataset . b. Divide the density profiles into 5 blocks. blocks.
c. Calculate the overburden stress.
d. Calculate the overburden gradient (overburden stress divided by depth).
Part 2: Compute porosity from density logs
a. Compute porosity assuming complete saturation and hydrostatic pore pressure. b. Plot porosity vs. depth for each dataset .
Part 3: Answers to Homework 1 Questions
Question 1: Density Profiles a. What is the logged density in the Barnett Shale well at 6000 ft depth in g/cc? = 2.7291 +/- 0.01 b. What is the logged density in the Gulf of Mexico well at 6000 ft depth in g/cc? = 2.22 +/- 0.01
Question 2: Overburden Stress Profiles a. What is the overburden stress in the Barnett Sha le well at 6000 ft depth in PSI? = 6606.1947 +/- 660.21223 b. What is the pore pressure in the Barnett Shale well at 6000 ft depth in PSI? = 2652.4502 +/- 265.24502 c. What is the overburden stress in the Gulf of Mexico well at 6000 ft depth in PSI? = 4740.8571+/- 474.08571 d. What is the pore pressure in the Gulf of Mexico well at 6000 ft depth in PSI? = 2652.4502 +/- 265.24502 Question 3: Overburden Stress Gradient Profiles a. What is the overburden stress gradient in the Barnett Shale well at 6000 ft depth in PSI/ft? = 1.101 +/- 0.11004 b. What is the overburden stress gradient in the Gulf of Mexico well at 6000 ft depth in PSI/ft? = 0.79014 +/- 0.079014
Question 4: Porosity Profiles a. What is the porosity in the Barnett Shale well at 5750 ft depth (as a unitless decimal, not as a percentage)? = 0.14382 +/- 0.01 b. What is the porosity in the Gulf of Mexico well at 5750 ft depth (as a unitless decimal, not as a percentage)? = 0.29765 +/- 0.01
