Exercise Directional Drilling Tools
1. Describe what general well pattern (Build-and-hold, Build-hold-and-drop, Continuous build, or Build-hold-and-build) you would employ to reach and produce the following target intervals:
(a) a thin carbonate reservoir with low matrix permeability and an extensive vertical fracture network.
(b) an oil-producing sandstone at a vertical depth of 5000 ft, located 800 ft southwest of the surface rig location.
(c) an oil zone underlying a large salt dome; surface location lies to the west of the salt dome.
Solution
(a) In a thin carbonate reservoir with low matrix permeability and an extensive vertical fracture network, the objective would be to intersect the fractures. Therefore, a wellbore perpendicular to the fracture network would be the best choice. Select the build-hold-and-build (horizontal) pattern.
(b) The target zone is located at a moderate depth, with a significant but not extended horizontal departure. Although the surface casing point is not specified, a good first choice would be to begin deflection below the surface casing and gradually build angle to total depth. Select the build-and-hold pattern.
(c) The best course would be to avoid the salt dome if possible. Drill the well vertically past the salt dome, then initiate a deep deflection to reach the oil zone. Select the continuous build pattern.
Assessment Directional Drilling Tools
1. What information does the directional driller NOT need in order to reset the toolface and correct a well’s trajectory?
A .Present inclination and azimuth of the hole
B .True vertical depth of the well ✔
C .Required change in inclination or azimuth
D .Rate of change (dog-leg) that the deflecting tool can provide
2. Which of the following is NOT an MWD component?
A .Pulser module
B .Sensor module
C .Electronics module
D .Inertial guidance system ✔
3. Generally the _______ a well’s target diameter or radius, the higher the drilling cost.
A .larger
B .smaller ✔
C .Neither of the above; target radius is unrelated to drilling cost.
4. In what type of formation might you consider using a jet bits with orienting nozzles to initiate wellbore deflection?
A .Fractured limestone
B .Soft shale ✔
C .Medium-to-hard sandstone
5. In which of these bottomhole assembly configurations would you NOT place a stabilizer directly above the bit?
A .Angle-building assembly
B .Angle-dropping assembly ✔
C .Angle-holding (packed hole) assembly
6. Considerations that are unique to controlled directional drilling include:
A .Trajectory planning
B .Optimizing weight on bit
C .Optimizing hydraulics
D .Use of downhole motors
E .A and D ✔
F .B and C
7. Which of the following well trajectories is particularly well suited for salt dome drilling?
A .Build and hold
B .Continuous build ✔
C .Build, hold and drop
D .Build, hold and build
8. What advantage does a rotary steerable system offer over a mud motor working in the “sliding” mode?
A .Improved hydraulic performance
B .Reduced friction and drag
C .Better weight transfer
D .A, B and C ✔
E .A and B only
9. What type of survey tool would you run inside a cased hole?
A .Magnetic
B .Gyroscopic ✔
C .Either A or B
D .Cannot run survey tools in cased hole.
10. Which of the following is the most accurate method of describing the well trajectory?
A .Tangential method
B .Angle-averaging method
C .Radius of curvature method ✔
D .Balanced tangential method
11. Which of these developments has made it possible to advance from geometric to geologic steering of well trajectories?
A .Bent-housing mud motors
B .MWD tools
C .Real-time formation evaluation capabilities ✔
12. Which of these statements about downhole mud motors is FALSE?
A .The use of a downhole motor tends to increase the rig’s power requirements. ✔
B .Downhole motors are used both for directional drilling and for controlling deviation in crooked hole formations.
C .The rotor in a positive displacement motor is turned by the action of the circulating drilling fluid.
D .Turbine motors have narrower operating ranges than positive displacement motors.
13. When describing the well trajectory, the method that requires the use of a dog-leg severity ratio factor is the:
A .Tangential method
B .Minimum curvature method ✔
C .Radius of curvature method
D .Angle averaging method
14. A wireline steering system uses _________ to measure direction and hole angle.
A .magnetometers
B .accelerometers
C .A and B ✔
15. A mechanical drift indicator provides a measurement of _________.
A .inclination from vertical ✔
B .azimuth
C .A and B
16. Which of these directional parameters is measured in the vertical plane?
A .build rate angle ✔
B .turn rate angle
C .lead angle
17. What types of formations causes signal complications for EMWD systems?
A .Sandstones containing high-salinity water
B .Shales
C .Anhydrites ✔
D .A and B only
18. Conventional MWD and LWD systems work in what type(s) of drilling fluid(s)?
A .Incompressible (i.e., continuous liquid phase) ✔
B .Compressible (i.e., air, gas or foam)
C .A and B
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