Petroleum Engineering 406

1. Petroleum Engineering 406 Lesson 21 Wellbore Trajectory Control

2. Lesson 18 - Wellbore Trajectory Control • Bent Motor and Bent Sub • Examples • Directional Drilling Measurements • Single Shot and Multishot • Magnetic and Gyro • Steering Tools • MWD tools

3. Homework READ: “Applied Drilling Engineering”, Ch. 8 (to page 390)

4. Nonmagnetic Drill Collar Orienting Sub Hole Bent Sub Mud Motor Bent Sub Angle Bit Fig. 8.39: Bent sub unconstrained and constrained in a wellbore. b is not necessarily equal to the bent sub angle, but it may be close in (a) above

5. Problem 1 • Determine the effective bent sub response for a 1 1/2o bent sub in a motor run where at 6,357’, a = 1o and e is S85E and at 6,382, aN = 1o and eN is S20E; the tool face is 160o right of high side.

6. Solution to Problem 1 • Calculate b from Eq. 8.53: • Dogleg severity:

7. Solution to Problem 1 - cont’d • If the mud motor length is 25 ft from the bit face to the bent sub, the maximum angle change that could be reached if there are no restrictions is: • The lower rate of build implies that the formation resisted the maximum rate of build by a factor of: An efficiency factor?

8. b = Bent Sub Angle? • Since the value of b for any given run may differ from the bent sub angle, it should not surprise us if Depredicted = Demeasured • Let us look at some examples.

9. Fig. 8.40: Example of three jetting stops while trying to kick off and set the wellbore lead.

10. Jetted 7’ 1745-52’ Surv 1722’: S32W 2.25o Nozzle Orientation g = -122o Orient S90E Final 1799’: S30E 2.75o

11. g = -80o Jetted 12’ 1850-62’ Surv 1814’ S20E 3.0o Orient N80E Final 1877’ S36E 3.25o

12. g = -74o Jetted 6’ 1925-31’ Surv 1877’ S36E 3.25o Orient N70E Final 1940’ S66E 4.75o

13. Directional Drilling Measurements • The trajectory of a wellbore is determined by the measurement of: • inclination q, a, I • direction f, e, A • measured depth DMD, DL, L

14. Directional Drilling Measurements - cont’d • A tool-face measurement is required to orient: • a whipstock • the large nozzle on a jetting bit • a bent sub or bent housing

15. Directional Drilling Measurements - cont’d • Tools available • single-shot magnetic or gyroscopic • multi-shot magnetic or gyroscopic • magnetometers, accelerometers, MWD tools

16. Magnetic Single-Shot Instrument • Records • inclination • direction • tool face position on sensitized paper or photographic film • Inclination may be determined by • a float on a liquid • a pendulum

17. Magnetic Single-Shot Instrument • Unit may be triggered by: • clock timer. • inertial timer (after stop). • Unit may be dropped (pumped down) and later retrieved by wireline or the drillpipe.

18. Magnetic Single-Shot Instrument • Single-shot instruments are used: • to monitor progress of directional-control well. • to monitor progress of deviation-control well. • to help orient tool face for trajectory change.

19. Magnetic Single-Shot Instrument - cont’d • Procedure: • load film into instrument • activate timer (activate stopwatch) • make up the tool • drop the tool • retrieve tool (wireline or drillpipe)

20. Light Housing Center Post Float Fluid Reference Mark Main Frame Photographic Disc B. 0-70o Angle-Compass Unit A. 0-20o Angle-Compass Unit Fig. 8.41: Schematic diagrams of magnetic single-shot angle-compass unit (courtesy Kuster Co.).

21. 1. Pendulum 2. Circular Glass 3. Compass 4. Pressure equalization 5. Cover glass Fig. 8.43: Pendulum suspended inclinometer and compass unit for a 0 to 17oo singe-shot unit. Indicated inclination 5o. Direction of inclination N 45 degrees 0’ or azimuth 45 degrees.

22. A/C Units Plumb-Bob Units Incl. Only Units Fig. 8.42: Single-shot film disks (courtesy of Kuster Co.). • Inclination • Direction • Tool Face Angle

23. Fig. 8.12: Pendulum assembly: a) plumb-bob angle unit b) drift arc inclinometer Pendulum Glass ring Piston (a) (b)

24. Hole direction with reference to Magnetic North Fig. 8.13: Schematic drawing of magnetic single and multi-shot instruments. N35oW I = 5.5o

25. Compass Inclination Scale Fig. 8.44: Cardan suspended compass and inclinometer for a single-shot 5o to 90o unit.

26. Wire Line Socket Rope Socket Overshot Swivel Stabilizer Stabilizer Fingers Fig. 8.45: Typical magnetic single-shottool with landing sub. Protective Case Orienting Anchor & Plug Mule ShoeMandrel Bottom Hole Orienting Sub Bottom Landing Assembly Takes time. Rig time is costly. Temperature limitation. May have to pump down.

27. Free Falling to Bottom Ready to be Dropped Tool seated Retrieve single shot Fig. 8.46: Typical single-shot operation.

28. Timer On 3 min. Single Shot Ready to be Dropped Compass Unit *Single Shot Instruments are run on slickline if there is a mule shoe sub in the hole Single Shot Free Falling in Mud to Bottom Fig. 8.46: Typical single-shot operation. Non Magnetic Drill Collar Orienting Sub Sleeve

29. 3 min. Fig. 8.46: Typical single-shot operation. Wireline unit to retrieve single shot 10 min. Overshot Used to Fish Single Shot Tool seated in orienting sleeve or at stop taking picture

30. Fishing Neck Top View Non Magnetic Collar Direction of Tool Face Via Bent Sub Single Shot Mule Shoe Orienting Sub Orienting Sleeve Lined up with Bent Sub Bent Sub Mud Motor Mule Shoe Key Position Fig. 8.47: Arrangement of the mule shoe for orienting a mud motor. Existing Centerline New Centerline

31. Magnetic Multishot Instruments • Are capable of taking numerous survey records in one run. • May be dropped down the drillpipe or run on wireline in open hole. • The unit contains a watch that is spring wound and uses the power of the spring to operate a timer cam.

32. Non-Magnetic Drill Collar(s) Compass Position Fig. 8.48: Typical arrangement for landing a multi-shot instrument. Multi-shot Instrument Landing Plate

33. Bottom Landing Fig. 8.49: Drop multi-shot survey instrument Rope Socket Stabilizer with Rubber Pins Battery Case Battery Connector Connector Shock Absorber Protective Instrument Barrel Watch Assembly Angle Unit Barrel Lower Ball Plug Aluminum Spacer Bar Bottom Shock AbsorberAssembly

34. Light Switch Lever Geneva Gear Watch Section Motor Knife SwitchTerminal Geneva Drive Wheel Assembly WindingStem Motor Lever Switch Watch Switch Film Sprocket Supply Film Spool Takeup FilmSpool Time Cycle Cam Fig. 8.50: Views of the watch and camera unit of atypical multi-shot tool.

35. Magnetic Multishot - cont’d • The multishot tool is usually dropped down the drillpipe and landed in the nonmagnetic drill collar. • During the trip out, a survey is taken every 90 ft, i.e. every stand.

36. Magnetic Multishot - cont’d • More closely spaced stations could be obtained by stopping the pipe more often, and waiting for a picture. • A stopwatch at the surface is synchronized with the instrument watch.

37. Fig. 8.51: Use of the surface watch while running a magnetic multi-shot operation. Synchronize with instrument watch by starting at the instant camera lights go on.

38. Time Intervals: A. 10 seconds - Lights are on, exposing film B. 15 seconds - Delay before moving. This is an allowance for instrument watch lag during survey.

39. Time Intervals - cont’d C. 20 seconds - Instrument is idle allowing movement of drill string without affecting picture. Most moves require sufficient time for taking one or more shots while moving D. 15 seconds - Minimum time for plumb bob and compass to settle for good picture, plus allowance for instrument gain during survey.

40. Fig. 8.52b: Projection of one survey frame for determining inclination and direction.

41. Steering Tools Standard Measuring Cable • Used with mud motors and bent sub • Can either pull every stand or use a side entry sub for continuous drilling Monel DC Probe Mule Shoe Bent Sub Mud Motor

42. MWD Tools

43. MWD Tools

44. Gyroscopic Tools • Non-magnetic drill collars used to prevent magnetic interference from drillstring • Gyros used if magnetic interference is from non drillstring source