Test 2

Question 1

List the four major functions of a drilling fluid

Answer 1

a. Clean bit and hole
b. Hydrostatic overbalance
c. Keep hole open
d. Cool & lubricate bit and drillstring

Question 2

List three advantages of water base mud (WBM)

Answer 2

Water Base Mud (WBM): Cheaper, environmental friendly, higher safety, better for logging, reduce the risk lost returns

Question 3

List three advantages of oil base mud (OBM)

Answer 3

Oil Base Mud (OBM): Stable at high temperature, higher ROP, better lubrication of bit, non-reactive with shales, reduce the risk of stuck pipe

Question 4

Which of the following kinds of solids “react” with the water in a water-base mud and are therefore considered active? (Circle letter in front of type of solid that is “active.”)

Answer 4

a. Barite
b. Bentonite - Active
c. Lost circulation materials (e.g. cellophane, pecan hulls)
d. Sand (drilled solids = cuttings)
e. Shale (drilled solids = cuttings) - Active
f. Limestone (drilled solids = cuttings)

Question 5

List two important properties of drilling fluids that will be used extensively in calculations for this class and in drilling engineering in general.

Answer 5

Density

Viscosity

Question 6

When ______3_____ at the __________5______ minus _______2_______ is higher than the highest ______4__________ plus _______1_______ for the rest of the hole.

Answer 6

Fracture EMW
Surface casing show
kick margin
Formation Pore EMW
Trip margin

Question 7

List the four major causes of abnormal formation pressures:

Answer 7

a. Compaction effects
b. Differential density effects
c. Diagenetic effects
d. Fluid migration effects

Question 8

Write a paragraph using complete sentences to explain why a pore pressure interpretation based on porosity might not give an accurate prediction of the pressure in a given permeable formation within the section where the interpretation was performed. (Think about the causes of abnormal pressure before writing.)

Answer 8

A pore pressure interpretation based on porosity is accurate for abnormal pressure caused by compaction effects. Therefore the interpretation would be inaccurate in differential density, fluid migration, and or diagenetic effects where present and significant.

Question 9

List four parameters that could potentially be measured during seismic, drilling or logging operations that can be used to indicate formation pressures in shales.

Answer 9

(a) _Any Porosity Dependent parameter__
(b) Resistivity, Conductivity, and sonic travel time (c) Neutron or Density log porosity, cuttings density (d) Seismic interval velocity, rate of penetration