370 likes | 757 Views
Read. Well Control ManualChapter 9Homework 2 Due Feb. 3, 1999. Content. Development of Abnormal PressureProperties of Normally Pressured FormationsProperties of Abnormally Pressured FormationsCasing Seat Selection. Knowledge of Pore and Fracture Pressures Leads to:. More effective well planningMaximize penetration rates with balanced drillingSafer and more economical selection of casing pointsMinimize trouble due to lost circulation and kicks.
E N D
1. Petroleum Engineering 406 Lesson 4
Well Control
2. Read Well Control Manual
Chapter 9
Homework 2 Due Feb. 3, 1999
3. Content Development of Abnormal Pressure
Properties of Normally Pressured Formations
Properties of Abnormally Pressured Formations
Casing Seat Selection
4. Knowledge of Pore and Fracture Pressures Leads to: More effective well planning
Maximize penetration rates with balanced drilling
Safer and more economical selection of casing points
Minimize trouble due to lost circulation and kicks
5. Knowledge of Pore and Fracture Pressures Leads to: Better engineered production and test equipment
Better understanding of local geology and drilling hazards
More accurate analysis of drilling data and electric logs
6. Normally Pressured Formation
7. Abnormal Formation Pressures Due to:
Incomplete compaction
Diagenesis
Differential Density in Dipping Formations
Fluid Migration
Tectonic Movement
Aquifers
Thermal Effects
8. Incomplete compaction
9. Diagenesis At 200oF to 300oF Clays undergo chemical alteration. Montmorillonite clays dehydrate and release some of the bound water into the space already occupied by free water, increasing pressure
10. Differential Density in Dipping Formations
11. Fluid Migration
12. Tectonic Movement - Uplifting
13. Tectonic Movement - Faulting
14. Aquifers
15. Thermal Effects Theories
Increased temperature with depth and chemical reactions cause increased pressures
Increased pressures caused increased temperatures
16. Salt Formations
17. Shale Properties used to Predict Pore Pressures Shales are used because:
Most pressure transition zones occur in relatively thick shales
Properties of clean shales are fairly homogeneous at any depth, and can be predicted with some degree of accuracy.
18. Shale Properties used to Predict Pore Pressures Shales are used because:
A deviation from the expected can be interpreted as a change in pressure gradient
Detecting these deviations in low permeability shales gives an early warning prior to drilling into pressured permeable formations, thus avoiding kicks.
19. Normally Pressured Shales Porosity - Decreases with depth
Density - Increases with depth
Conductivity - Decreases with depth
Resistivity - Increases with depth
Sonic travel time - Decreases with depth
Temp. gradient - Relatively constant
20. Abnormally Pressured Shales Porosity - Higher than expected
Density - Lower than expected
Conductivity - Higher than expected
Resistivity - Lower than expected
Sonic travel time - Higher than expected
Temp gradient - Increases
21. Porosity Density Conductivity Sonic
22. Temperature gradient - Increases
23. Pore Pressure Prediction Occurs: Prior to drilling
During drilling
After drilling
24. Before Drilling Offset mud records, drilling reports, bit records, well tests
Geological Correlation
25. Before Drilling Open Hole Logs from offset wells
26. Before Drilling Seismic data
27. During Drilling Kick - SIDPP and HSP in DP can give accurate measurement of formation pore pressure
LOT - gives accurate measurement of fracture pressure
28. During Drilling Correlation of penetration rate to offset logs
Changes in shale penetration rate
29. During Drilling Shale density Change
Mercury pump
Mud balance
Fill mud balance with clean shale until it balances at 8.33 ppg
Fill the balance cup with water and determine total weight
Calculate shale bulk density:
SBD=8.33/(16.66-Total Weight)
30. During Drilling Shale density Change - Density column
31. During Drilling Mud gas content change
32. During drilling Shale cutting change
33. During Drilling Mud chloride change
Increase in fill on bottom
Increase in drag or torque
Contaminated mud
Temperature change
34. During Drilling Abnormal trip fill-up behavior
Periodic logging runs
Drill-stem tests
MWD or LWD tools
Paleontology
35. During Drilling dc-exponent
P=K*(W/D)d*Ne
P=penetration rate of shale
K=formation drillability
W=weight on bit
D=bit diameter
N=rotary speed
d=bit weight exponent
e=rotary speed exponent
36. During Drilling
37. During Drilling
38. After Drilling Log evaluation
Flow tests
BHP surveys
Shut-in pressure tests
Analysis of mud reports, drilling reports, and bit records